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Nair VV, Kish BR, Oshima H, Wright AM, Wen Q, Schwichtenberg AJ, Tong Y. Amplitude fluctuations of cerebrovascular oscillations and CSF movement desynchronize during NREM3 sleep. J Cereb Blood Flow Metab 2025:271678X251337637. [PMID: 40370321 DOI: 10.1177/0271678x251337637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 05/16/2025]
Abstract
Fluctuations in cerebral blood volume (CBV) are a dominant mechanism aiding cerebrospinal fluid (CSF) movement in the brain during wakefulness and non-rapid eye movement (NREM) sleep. However, it is unclear if the amplitudes of CBV oscillations also change in proportion to the changes in amplitude of CSF movement across specific NREM sleep states. It is also not known if the coupling strength between them varies between NREM sleep states. To investigate these relationships, we measured cerebral hemodynamics and craniad CSF movement at the fourth ventricle simultaneously during wakefulness and NREM sleep states using concurrent Electroencephalography and functional Magnetic Resonance Imaging. We found that the amplitude fluctuations of cerebral hemodynamics and CSF oscillations desynchronize from one another only during deep NREM3 state, despite the strong mechanical coupling between CBV changes and CSF movement, which was consistent across all states. This suggests the existence of a different mechanism, linked to the cortical interstitial volume/resistance change, that regulates the NREM3 CSF inflow into the brain.
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Affiliation(s)
- Vidhya V Nair
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Brianna R Kish
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
| | - Hideyuki Oshima
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- Graduate School of Engineering and Science, Shibaura Institute of Technology, Japan
| | - Adam M Wright
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Qiuting Wen
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - A J Schwichtenberg
- Department of Human Development and Family Science, College of Health and Human Sciences, Purdue University, West Lafayette, IN, USA
| | - Yunjie Tong
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA
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2
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Kozberg MG, Munting LP, Hanlin LH, Auger CA, van den Berg ML, Denis de Senneville B, Hirschler L, Warnking JM, Barbier EL, Farrar CT, Greenberg SM, Bacskai BJ, van Veluw SJ. Vasomotion loss precedes impaired cerebrovascular reactivity and microbleeds in cerebral amyloid angiopathy. Brain Commun 2025; 7:fcaf186. [PMID: 40406166 PMCID: PMC12096159 DOI: 10.1093/braincomms/fcaf186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 04/11/2025] [Accepted: 05/12/2025] [Indexed: 05/26/2025] Open
Abstract
Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease in which amyloid-β accumulates in vessel walls. CAA is a leading cause of symptomatic lobar intracerebral haemorrhage and an important contributor to age-related cognitive decline. Recent work has suggested that vascular dysfunction may precede symptomatic stages of CAA, and that spontaneous slow oscillations in arteriolar diameter (termed vasomotion), important for amyloid-β clearance, may be impaired in CAA. To systematically study the progression of vascular dysfunction in CAA, we used the APP23 mouse model of amyloidosis, which is known to develop spontaneous cerebral microbleeds mimicking human CAA. Using in vivo 2-photon microscopy, we longitudinally imaged unanesthetized APP23 transgenic mice and wildtype (WT) littermates from 7 to 14 months of age, tracking amyloid-β accumulation and vasomotion in individual pial arterioles over time. MRI was used in separate groups of 12-, 18- and 24-month-old APP23 transgenic mice and WT littermates to detect microbleeds and to assess cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) with pseudo-continuous arterial spin labelling. We observed a significant decline in vasomotion with age in APP23 mice, while vasomotion remained unchanged in WT mice with age. This decline corresponded in timing to initial vascular amyloid-β deposition (∼8-10 months of age), although it was more strongly correlated with age than with vascular amyloid-β burden in individual arterioles. Declines in vasomotion preceded the development of MRI-visible microbleeds and the loss of smooth muscle actin in arterioles, both of which were observed in the majority of APP23 mice by 18 months of age. Additionally, CBF and evoked CVR were intact in APP23 mice at 12 months of age, but significantly lower in APP23 mice by 24 months of age. Our findings suggest that a decline in spontaneous vasomotion is an early, potentially pre-symptomatic, manifestation of CAA and vascular dysfunction, and a possible future treatment target.
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Affiliation(s)
- Mariel G Kozberg
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Leon P Munting
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Lee H Hanlin
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Corinne A Auger
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | | | | | - Lydiane Hirschler
- Department of Radiology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Jan M Warnking
- Univ. Grenoble Alpes, Inserm, Grenoble Institut Neurosciences, U1216, Grenoble 38000, France
| | - Emmanuel L Barbier
- Univ. Grenoble Alpes, Inserm, Grenoble Institut Neurosciences, U1216, Grenoble 38000, France
| | - Christian T Farrar
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Brian J Bacskai
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Susanne J van Veluw
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA
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3
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Lucey BP. Sleep Alterations and Cognitive Decline. Semin Neurol 2025. [PMID: 40081821 DOI: 10.1055/a-2557-8422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2025]
Abstract
Sleep disturbances and cognitive decline are intricately connected, and both are prevalent in aging populations and individuals with neurodegenerative disorders such as Alzheimer's disease (AD) and other dementias. Sleep is vital for cognitive functions including memory consolidation, executive function, and attention. Disruption in these processes is associated with cognitive decline, although causal evidence is mixed. This review delves into the bidirectional relationship between alterations in sleep and cognitive impairment, exploring key mechanisms such as amyloid-β accumulation, tau pathology, synaptic homeostasis, neurotransmitter dysregulation, oxidative stress, and vascular contributions. Evidence from both experimental research and population-based studies underscores the necessity of early interventions targeting sleep to mitigate risks of neurodegenerative diseases. A deeper understanding of the interplay between sleep and cognitive health may pave the way for innovative strategies to prevent or reduce cognitive decline through improved sleep management.
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Affiliation(s)
- Brendan P Lucey
- Department of Neurology, Washington University School of Medicine, St Louis, Missouri
- Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, Missouri
- Center On Biological Rhythms and Sleep, Washington University School of Medicine, St Louis, Missouri
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4
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Mirg S, Samanta K, Chen H, Jiang J, Turner KL, Salehi F, Ramiah KM, Drew PJ, Kothapalli SR. Integrated Ultrasound Neuromodulation and Optical Neuroimaging in Awake Mice using a Transparent Ultrasound Transducer Cranial Window. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.19.638722. [PMID: 40060492 PMCID: PMC11888234 DOI: 10.1101/2025.02.19.638722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 03/17/2025]
Abstract
Ultrasound neuromodulation is a rapidly advancing, non-invasive technique with significant therapeutic potential for treating various neurological disorders. Although extensive in vitro and in vivo studies have provided valuable insights into its modulatory effects, the underlying mechanisms remain poorly understood, limiting its clinical translation. Optical neuroimaging techniques can help investigate these mechanisms; however, the opacity and bulkiness of conventional ultrasound transducers pose significant challenges for their integration with in vivo ultrasound neuromodulation studies, particularly in awake rodents. To address these limitations, we propose a straightforward solution: a miniaturized lithium niobate-based transparent ultrasound transducer (TUT) integrated as a thinned-skull cranial window for ultrasound stimulation while facilitating multimodal optical neuroimaging in awake mice brain. Using laser speckle contrast imaging and intrinsic optical signal imaging, we studied changes in brain hemodynamics in response to various ultrasound stimulation sequences. Our experiments demonstrated that TUT cranial window can robustly induce neuromodulatory effects with observed increase in both cerebral blood flow and total hemoglobin, with peak and cumulative hemodynamic changes directionally correlated with ultrasound stimulation duration and intensity. Overall, these findings highlight that TUT cranial window can seamlessly integrate ultrasound stimulation and optical neuroimaging in awake mouse brain models, offering promising prospects for uncovering the underlying mechanisms of ultrasound neuromodulation.
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Affiliation(s)
- Shubham Mirg
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
- Center for Neural Engineering, Pennsylvania State University, PA 16802,USA
| | - Krishnendu Samanta
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
| | - Haoyang Chen
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
- Center for Neural Engineering, Pennsylvania State University, PA 16802,USA
| | - Jin Jiang
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
| | - Kevin L Turner
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
| | - Fatemeh Salehi
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
| | - Kathiravan M Ramiah
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
| | - Patrick J Drew
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
- Center for Neural Engineering, Pennsylvania State University, PA 16802,USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA 16802, USA
| | - Sri-Rajasekhar Kothapalli
- Department of Biomedical Engineering, Pennsylvania State University, PA 16802, USA
- Center for Neural Engineering, Pennsylvania State University, PA 16802,USA
- Penn State Cancer Institute, Hershey, PA, 17033, USA
- Graduate Program in Acoustics, Pennsylvania State University, PA 16802, USA
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5
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Zhang X, Tao L, Nygaard AH, Dong Y, Groves T, Hong X, Goddard CM, He C, Postnov D, Allodi I, Lauritzen MJ, Cai C. Aging alters calcium signaling in vascular mural cells and drives remodeling of neurovascular coupling in the awake brain. J Cereb Blood Flow Metab 2025:271678X251320455. [PMID: 39947907 PMCID: PMC11826828 DOI: 10.1177/0271678x251320455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2024] [Revised: 11/11/2024] [Accepted: 01/26/2025] [Indexed: 02/16/2025]
Abstract
Brain aging leads to reduced cerebral blood flow and cognitive decline, but how normal aging affects neurovascular coupling (NVC) in the awake brain is unclear. Here, we investigated NVC in relation to calcium changes in vascular mural cells (VMCs) in awake adult and aged mice. We show that NVC responses are reduced and prolonged in the aged brain and that this is more pronounced at the capillary level than in arterioles. However, the overall NVC response, measured as the time integral of vasodilation, is the same in the two age groups. In adult, but not in aged mice, the NVC response correlated with Ca2+ signaling in VMCs, while the overall Ca2+ kinetics were slower in aged than in adult mice. In particular, the rate of Ca2+ transport, and the Ca2+ sensitivity of VMCs were reduced in aged mice, explaining the reduced and prolonged vasodilation. Spontaneous locomotion was less frequent and reduced in aged mice as compared to young adult mice, and this was reflected in the 'slow but prolonged' NVC and vascular Ca2+ responses. Taken together, our data characterize the NVC in the aged, awake brain as slow but prolonged, highlighting the remodeling processes associated with aging.
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Affiliation(s)
- Xiao Zhang
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Lechan Tao
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Amalie H Nygaard
- Novo Nordisk Foundation Center for Stem Cell Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Yiqiu Dong
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Copenhagen, Denmark
| | - Teddy Groves
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Copenhagen, Denmark
| | - Xiaoqi Hong
- Department of Anatomy and Physiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Carolyn M Goddard
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Chen He
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Dmitry Postnov
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Copenhagen, Denmark
| | - Ilary Allodi
- Neural Circuits of Disease Laboratory, School of Psychology and Neuroscience, University of St Andrews, St Andrews, UK
| | - Martin J Lauritzen
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Changsi Cai
- Department of Neuroscience, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
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6
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Turner KL, Brockway DF, Hossain MS, Griffith KR, Greenawalt DI, Zhang Q, Gheres KW, Crowley NA, Drew PJ. Type-I nNOS neurons orchestrate cortical neural activity and vasomotion. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.01.21.634042. [PMID: 39896560 PMCID: PMC11785022 DOI: 10.1101/2025.01.21.634042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2025]
Abstract
It is unknown how the brain orchestrates coordination of global neural and vascular dynamics. We sought to uncover the role of a sparse but unusual population of genetically-distinct interneurons known as type-I nNOS neurons, using a novel pharmacological strategic to unilaterally ablate these neurons from the somatosensory cortex of mice. Region-specific ablation produced changes in both neural activity and vascular dynamics, decreased power in the delta-band of the local field potential, reduced sustained vascular responses to prolonged sensory stimulation, and abolished the post-stimulus undershoot in cerebral blood volume. Coherence between the left and right somatosensory cortex gamma-band power envelope and blood volume at ultra-low frequencies was decreased, suggesting type-1 nNOS neurons integrate long-range coordination of brain signals. Lastly, we observed decreases in the amplitude of resting-state blood volume oscillations and decreased vasomotion following the ablation of type-I nNOS neurons. This demonstrates that a small population of nNOS-positive neurons are indispensable for regulating both neural and vascular dynamics in the whole brain and implicates disruption of these neurons in diseases ranging from neurodegeneration to sleep disturbances.
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Affiliation(s)
- Kevin L. Turner
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Dakota F. Brockway
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Md Shakhawat Hossain
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Keith R. Griffith
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Denver I. Greenawalt
- Graduate Program in Molecular Cellular and Integrative Biosciences, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
- Department of Physiology, Michigan State University, East Lansing, MI 48824
| | - Kyle W. Gheres
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Nicole A. Crowley
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Biology, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
| | - Patrick J. Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA 16802
- Penn State Neuroscience Institute, The Pennsylvania State University, University Park, PA 16802
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7
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Hauglund NL, Andersen M, Tokarska K, Radovanovic T, Kjaerby C, Sørensen FL, Bojarowska Z, Untiet V, Ballestero SB, Kolmos MG, Weikop P, Hirase H, Nedergaard M. Norepinephrine-mediated slow vasomotion drives glymphatic clearance during sleep. Cell 2025; 188:606-622.e17. [PMID: 39788123 DOI: 10.1016/j.cell.2024.11.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 08/29/2024] [Accepted: 11/18/2024] [Indexed: 01/12/2025]
Abstract
As the brain transitions from wakefulness to sleep, processing of external information diminishes while restorative processes, such as glymphatic removal of waste products, are activated. Yet, it is not known what drives brain clearance during sleep. We here employed an array of technologies and identified tightly synchronized oscillations in norepinephrine, cerebral blood volume, and cerebrospinal fluid (CSF) as the strongest predictors of glymphatic clearance during NREM sleep. Optogenetic stimulation of the locus coeruleus induced anti-correlated changes in vasomotion and CSF signal. Furthermore, stimulation of arterial oscillations enhanced CSF inflow, demonstrating that vasomotion acts as a pump driving CSF into the brain. On the contrary, the sleep aid zolpidem suppressed norepinephrine oscillations and glymphatic flow, highlighting the critical role of norepinephrine-driven vascular dynamics in brain clearance. Thus, the micro-architectural organization of NREM sleep, driven by norepinephrine fluctuations and vascular dynamics, is a key determinant for glymphatic clearance.
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Affiliation(s)
- Natalie L Hauglund
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark; Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK; Danish Center for Sleep Medicine, Department of Clinical Neurophysiology, Rigshospitalet, 2600 Glostrup, Denmark
| | - Mie Andersen
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Klaudia Tokarska
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Tessa Radovanovic
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Celia Kjaerby
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Frederikke L Sørensen
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Zuzanna Bojarowska
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Verena Untiet
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Sheyla B Ballestero
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Mie G Kolmos
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Pia Weikop
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Hajime Hirase
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen N, Denmark; Center for Translational Neuromedicine, University of Rochester, Rochester, NY 14627, USA.
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8
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Garborg CS, Ghitti B, Zhang Q, Ricotta JM, Frank N, Mueller SJ, Greenawalt DI, Turner KL, Kedarasetti RT, Mostafa M, Lee H, Costanzo F, Drew PJ. Gut-Brain Hydraulics: Brain motion and CSF circulation is driven by mechanical coupling with the abdomen. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.01.30.635779. [PMID: 39974937 PMCID: PMC11838368 DOI: 10.1101/2025.01.30.635779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2025]
Abstract
The brain moves within the skull, but the drivers and function of this motion are not understood. We visualized brain motion relative to the skull in awake head-fixed mice using high-speed, multi-plane two-photon microscopy. Brain motion was primarily rostrally and laterally directed, and was tightly correlated with locomotion, but not with respiration or the cardiac cycle. Electromyography recordings in abdominal muscles and microCT reconstructions of the trunk and spinal vasculature showed that brain motion was driven by abdominal muscle contractions that activate a hydraulic-like vascular connection between the nervous system and the abdominal cavity. Externally-applied abdominal pressure generated brain motion similar to those seen during abdominal muscle contractions. Simulations showed that brain motion drives substantial volumes of interstitial fluid through and out of the brain (at volumetric rates several times higher than production) into the subarachnoid space, in the opposite direction of fluid flow seen during sleep. The brain is hydraulically linked to the abdominal compartment, and fluid flow in the brain is coupled to body movements, providing a mechanism by which the mechanics of the viscera directly impact brain health.
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9
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Sun YR, Lv QK, Liu JY, Wang F, Liu CF. New perspectives on the glymphatic system and the relationship between glymphatic system and neurodegenerative diseases. Neurobiol Dis 2025; 205:106791. [PMID: 39778750 DOI: 10.1016/j.nbd.2025.106791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2024] [Revised: 01/03/2025] [Accepted: 01/03/2025] [Indexed: 01/11/2025] Open
Abstract
Neurodegenerative diseases (ND) are characterized by the accumulation of aggregated proteins. The glymphatic system, through its rapid exchange mechanisms between cerebrospinal fluid (CSF) and interstitial fluid (ISF), facilitates the movement of metabolic substances within the brain, serving functions akin to those of the peripheral lymphatic system. This emerging waste clearance mechanism offers a novel perspective on the removal of pathological substances in ND. This article elucidates recent discoveries regarding the glymphatic system and updates relevant concepts within its model. It discusses the potential roles of the glymphatic system in ND, including Alzheimer's disease (AD), Parkinson's disease (PD), and multiple system atrophy (MSA), and proposes the glymphatic system as a novel therapeutic target for these conditions.
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Affiliation(s)
- Yan-Rui Sun
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China; Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou 215123, China
| | - Qian-Kun Lv
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China; Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou 215123, China
| | - Jun-Yi Liu
- Department of Neurology, Dushu Lake hospital affilicated to Soochow University, Suzhou, China
| | - Fen Wang
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China; Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou 215123, China.
| | - Chun-Feng Liu
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou 215004, China; Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou 215123, China.
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10
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Meyer-Baese L, Jaeger D, Keilholz S. Neurovascular coupling: a review of spontaneous neocortical dynamics linking neuronal activity to hemodynamics and what we have learned from the rodent brain. J Neurophysiol 2025; 133:644-660. [PMID: 39819035 DOI: 10.1152/jn.00418.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2024] [Revised: 11/18/2024] [Accepted: 01/02/2025] [Indexed: 01/19/2025] Open
Abstract
The brain is a complex neural network whose functional dynamics offer valuable insights into behavioral performance and health. Advances in fMRI have provided a unique window into studying human brain networks, providing us with a powerful tool for clinical research. Yet many questions about the underlying correlates between spontaneous fMRI and neural activity remain poorly understood, limiting the impact of this research. Cross-species studies have proven essential in deepening our understanding of how neuronal activity is coupled to increases in local cerebral blood flow, changes in blood oxygenation, and the measured fMRI signal. In this article, we review some fundamental mechanisms implicated in neurovascular coupling. We then examine neurovascular coupling within the context of spontaneous cortical functional networks and their dynamics, summarizing key findings from mechanistic studies in rodents. In doing so, we highlight the nuances of the neurovascular coupling that ultimately influences the interpretation of derived hemodynamic functional networks, their dynamics, and the neural underpinnings they represent.
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Affiliation(s)
- Lisa Meyer-Baese
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
- Department of Biology, Emory University, Atlanta, Georgia, United States
| | - Dieter Jaeger
- Department of Biology, Emory University, Atlanta, Georgia, United States
| | - Shella Keilholz
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, Georgia, United States
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11
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Bisht A, Peringod G, Yu L, Cheng N, Gordon GR, Murari K. Tetherless miniaturized point detector device for monitoring cortical surface hemodynamics in mice. JOURNAL OF BIOMEDICAL OPTICS 2025; 30:S23904. [PMID: 40110227 PMCID: PMC11922257 DOI: 10.1117/1.jbo.30.s2.s23904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2024] [Revised: 02/11/2025] [Accepted: 02/17/2025] [Indexed: 03/22/2025]
Abstract
Significance Several miniaturized optical neuroimaging devices for preclinical studies mimicking benchtop instrumentation have been proposed in the past. However, they are generally relatively large, complex, and power-hungry, limiting their usability for long-term measurements in freely moving animals. Further, there is limited research in the development of algorithms to analyze long-term signals. Aim We aim to develop a cost-effective, easy-to-use miniaturized intrinsic optical monitoring system (TinyIOMS) that can be reliably used to record spontaneous and stimulus-evoked hemodynamic changes and further cluster brain states based on hemodynamic features. Approach We present the design and fabrication of TinyIOMS ( 8 mm × 13 mm × 9 mm 3 , 1.2 g with battery). A standard camera-based widefield system (WFIOS) is used to validate the TinyIOMS signals. Next, TinyIOMS is used to continuously record stimulus-evoked activity and spontaneous activity for 7 h in chronically implanted mice. We further show up to 2 days of intermittent recording from an animal. An unsupervised machine learning algorithm is used to analyze the TinyIOMS signals. Results We observed that the TinyIOMS data is comparable to the WFIOS data. Stimulus-evoked activity recorded using the TinyIOMS was distinguishable based on stimulus magnitude. Using TinyIOMS, we successfully achieved 7 h of continuous recording and up to 2 days of intermittent recording in its home cage placed in the animal housing facility, i.e., outside a controlled lab environment. Using an unsupervised machine learning algorithm ( k -means clustering), we observed the grouping of data into two clusters representing asleep and awake states with an accuracy of ∼ 91 % . The same algorithm was then applied to the 2-day-long dataset, where similar clusters emerged. Conclusions TinyIOMS can be used for long-term hemodynamic monitoring applications in mice. Results indicate that the device is suitable for measurements in freely moving mice during behavioral studies synchronized with behavioral video monitoring and external stimuli.
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Affiliation(s)
- Anupam Bisht
- University of Calgary, Department of Biomedical Engineering, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
| | - Govind Peringod
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- University of Calgary, Cumming School of Medicine, Department of Physiology and Pharmacology, Calgary, Alberta, Canada
| | - Linhui Yu
- University of Calgary, Electrical and Software Engineering, Calgary, Alberta, Canada
| | - Ning Cheng
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- University of Calgary, Faculty of Veterinary Medicine, Calgary, Alberta, Canada
- Owerko Centre and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada
| | - Grant R. Gordon
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- University of Calgary, Cumming School of Medicine, Department of Physiology and Pharmacology, Calgary, Alberta, Canada
| | - Kartikeya Murari
- University of Calgary, Department of Biomedical Engineering, Calgary, Alberta, Canada
- University of Calgary, Hotchkiss Brain Institute, Calgary, Alberta, Canada
- University of Calgary, Electrical and Software Engineering, Calgary, Alberta, Canada
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12
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Jacob MS, Roach BJ, Mathalon DH, Ford JM. Noncanonical EEG-BOLD coupling by default and in schizophrenia. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2025:2025.01.14.25320216. [PMID: 39867401 PMCID: PMC11759611 DOI: 10.1101/2025.01.14.25320216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/28/2025]
Abstract
Neuroimaging methods rely on models of neurovascular coupling that assume hemodynamic responses evolve seconds after changes in neural activity. However, emerging evidence reveals noncanonical BOLD (blood oxygen level dependent) responses that are delayed under stress and aberrant in neuropsychiatric conditions. To investigate BOLD coupling to resting-state fluctuations in neural activity, we simultaneously recorded EEG and fMRI in people with schizophrenia and psychiatrically unaffected participants. We focus on alpha band power to examine voxelwise, time-lagged BOLD correlations. Principally, we find diversity in the temporal profile of alpha-BOLD coupling within regions of the default mode network (DMN). This includes early coupling (0-2 seconds BOLD lag) for more posterior regions, thalamus and brainstem. Anterior regions of the DMN show coupling at canonical lags (4-6 seconds), with greater lag scores associated with self-reported measures of stress and greater lag scores in participants with schizophrenia. Overall, noncanonical alpha-BOLD coupling is widespread across the DMN and other non-cortical regions, and is delayed in people with schizophrenia. These findings are consistent with a "hemo-neural" hypothesis, that blood flow and/or metabolism can regulate ongoing neural activity, and further, that the hemo-neural lag may be associated with subjective arousal or stress. Our work highlights the need for more studies of neurovascular coupling in psychiatric conditions.
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Affiliation(s)
- Michael S Jacob
- San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA, 94121, United States
- University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA, 94143, United States
| | - Brian J Roach
- San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA, 94121, United States
| | - Daniel H Mathalon
- San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA, 94121, United States
- University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA, 94143, United States
| | - Judith M Ford
- San Francisco VA Medical Center, 4150 Clement St, San Francisco, CA, 94121, United States
- University of California, San Francisco, 505 Parnassus Ave, San Francisco, CA, 94143, United States
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13
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Meinhold L, Gennari AG, Baumann-Vogel H, Werth E, Schreiner SJ, Ineichen C, Baumann CR, O’Gorman Tuura R. T2 MRI visible perivascular spaces in Parkinson's disease: clinical significance and association with polysomnography measured sleep. Sleep 2025; 48:zsae233. [PMID: 39377177 PMCID: PMC11725513 DOI: 10.1093/sleep/zsae233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Revised: 09/26/2024] [Indexed: 10/09/2024] Open
Abstract
Poor sleep quality might contribute to the risk and progression of neurodegenerative disorders via deficient cerebral waste clearance functions during sleep. In this retrospective cross-sectional study, we explore the link between enlarged perivascular spaces (PVS), a putative marker of sleep-dependent glymphatic clearance, with sleep quality and motor symptoms in patients with Parkinson's disease (PD). T2-weighted magnetic resonance imaging (MRI) images of 20 patients and 17 healthy control participants were estimated visually for PVS in the basal ganglia (BG) and centrum semiovale (CSO). The patient group additionally underwent a single-night polysomnography. Readouts included polysomnographic sleep features and slow-wave activity (SWA), a quantitative EEG marker of sleep depth. Associations between PVS counts, PD symptoms (MDS-UPDRS scores), and sleep parameters were evaluated using correlation and regression analyses. Intra- and inter-rater reproducibility was assessed with weighted Cohen`s kappa coefficient. BG and CSO PVS counts in both patients and controls did not differ significantly between groups. In patients, PVS in both brain regions was negatively associated with SWA (1-2 Hz; BG: r(15) = -.58, padj = .015 and CSO: r(15) = -.6, padj = .015). Basal ganglia PVS counts were positively associated with motor symptoms of daily living (IRR = 1.05, CI [1.01, 1.09], p = .007, padj = .026) and antidepressant use (IRR = 1.37, CI [1.05, 1.80], p = .021, padj = .043) after controlling for age. Centrum Semiovale PVS counts in patients were positively associated with a diagnosis of REM sleep behavior disorder (IRR = 1.39, CI [1.06, 1.84], p = .018, padj = .11). These results add to evidence that sleep deterioration may play a role in impairing glymphatic clearance via altered perivascular function, potentially contributing to disease severity in PD patients.
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Affiliation(s)
- Lena Meinhold
- Center for MR Research, University Children’s Hospital, Zurich, Switzerland
- University of Zurich Sleep & Health Competence Center, Zurich, Switzerland
| | - Antonio G Gennari
- Center for MR Research, University Children’s Hospital, Zurich, Switzerland
| | - Heide Baumann-Vogel
- Zentrum für Soziale Psychiatrie, Psychiatric University Hospital Zurich, Zurich, Switzerland
| | - Esther Werth
- University of Zurich Sleep & Health Competence Center, Zurich, Switzerland
- Department of Neurology, University Hospital, Zurich, Switzerland
| | - Simon J Schreiner
- University of Zurich Sleep & Health Competence Center, Zurich, Switzerland
- Department of Neurology, University Hospital, Zurich, Switzerland
| | | | - Christian R Baumann
- University of Zurich Sleep & Health Competence Center, Zurich, Switzerland
- Department of Neurology, University Hospital, Zurich, Switzerland
| | - Ruth O’Gorman Tuura
- Center for MR Research, University Children’s Hospital, Zurich, Switzerland
- University of Zurich Sleep & Health Competence Center, Zurich, Switzerland
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14
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Eyre B, Shaw K, Drew D, Rayson A, Shabir O, Lee L, Francis S, Berwick J, Howarth C. Characterizing vascular function in mouse models of Alzheimer's disease, atherosclerosis, and mixed Alzheimer's and atherosclerosis. NEUROPHOTONICS 2025; 12:S14610. [PMID: 40405889 PMCID: PMC12094910 DOI: 10.1117/1.nph.12.s1.s14610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/29/2024] [Revised: 02/27/2025] [Accepted: 04/08/2025] [Indexed: 05/26/2025]
Abstract
Significance Alzheimer's disease does not occur in isolation, and there are many comorbidities associated with the disease, especially diseases of the vasculature. Atherosclerosis is a known risk factor for the subsequent development of Alzheimer's disease; therefore, understanding how both diseases interact will provide a greater understanding of co-morbid disease progression and aid the development of potential new treatments. Aim We characterize hemodynamic responses and cognitive performance in APP/PS1 Alzheimer's mice, atherosclerosis mice, and a mixed disease group (APP/PS1 and atherosclerosis) between the ages of 9 and 12 months. Approach Whisker-evoked hemodynamic responses and recognition memory were assessed in awake mice, immunohistochemistry to assess amyloid pathology, and histology to characterize atherosclerotic plaque load. Results We observed hemodynamic deficits in atherosclerosis mice (versus Alzheimer's, mixed disease, or wild-type mice), with reduced short-duration stimulus-evoked hemodynamic responses occurring when there was no concurrent locomotion during the stimulation period. Mixed Alzheimer's and atherosclerosis models did not show differences in amyloid beta coverage in the cortex or hippocampus or atherosclerotic plaque burden in the aortic arch vs relevant Alzheimer's or atherosclerosis controls. Consistent with the subtle vascular deficits and no pathology differences, we also observed no difference in performance on the object recognition task across groups. Conclusions These results emphasize the importance of experimental design for characterizing vascular function across disease groups, as locomotion and stimulus duration impacted the ability to detect differences between groups. Although atherosclerosis did reduce hemodynamic responses, these were recovered in the presence of co-occurring Alzheimer's disease, which may provide targets for future studies to explore the potentially contrasting vasodilatory mechanisms these diseases impact.
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Affiliation(s)
- Beth Eyre
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
- Massachusetts General Hospital, Harvard Medical School, Department of Neurology, Boston, Massachusetts, United States
| | - Kira Shaw
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
| | - Dave Drew
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
| | - Alexandra Rayson
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
- University of Sheffield, School of Medicine and Population Health, Sheffield, United Kingdom
| | - Osman Shabir
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
- University of Sheffield, School of Medicine and Population Health, Sheffield, United Kingdom
| | - Llywelyn Lee
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
| | - Sheila Francis
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
- University of Sheffield, School of Medicine and Population Health, Sheffield, United Kingdom
| | - Jason Berwick
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
| | - Clare Howarth
- University of Sheffield, Department of Psychology, Sheffield Neurovascular Group, Sheffield, United Kingdom
- University of Sheffield, Neuroscience Institute, Sheffield, United Kingdom
- University of Sheffield, Healthy Lifespan Institute, Sheffield, United Kingdom
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15
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Yang L, Zhao W, Kan Y, Ren C, Ji X. From Mechanisms to Medicine: Neurovascular Coupling in the Diagnosis and Treatment of Cerebrovascular Disorders: A Narrative Review. Cells 2024; 14:16. [PMID: 39791717 PMCID: PMC11719775 DOI: 10.3390/cells14010016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2024] [Revised: 12/20/2024] [Accepted: 12/24/2024] [Indexed: 01/12/2025] Open
Abstract
Neurovascular coupling (NVC) refers to the process of local changes in cerebral blood flow (CBF) after neuronal activity, which ensures the timely and adequate supply of oxygen, glucose, and substrates to the active regions of the brain. Recent clinical imaging and experimental technology advancements have deepened our understanding of the cellular mechanisms underlying NVC. Pathological conditions such as stroke, subarachnoid hemorrhage, cerebral small vascular disease, and vascular cognitive impairment can disrupt NVC even before clinical symptoms appear. However, the complexity of the underlying mechanism remains unclear. This review discusses basic and clinical experimental evidence on how neural activity sensitively communicates with the vasculature to cause spatial changes in blood flow in cerebrovascular diseases. A deeper understanding of how neurovascular unit-related cells participate in NVC regulation is necessary to better understand blood flow and nerve activity recovery in cerebrovascular diseases.
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Affiliation(s)
- Lu Yang
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; (L.Y.); (W.Z.); (Y.K.)
| | - Wenbo Zhao
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; (L.Y.); (W.Z.); (Y.K.)
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100054, China
| | - Yuan Kan
- Department of Neurology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China; (L.Y.); (W.Z.); (Y.K.)
| | - Changhong Ren
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100054, China
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
| | - Xunming Ji
- Beijing Institute of Brain Disorders, Capital Medical University, Beijing 100054, China
- Beijing Key Laboratory of Hypoxic Conditioning Translational Medicine, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100053, China
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16
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Han F, Liu X, Yang Y, Liu X. Sex-specific age-related differences in cerebrospinal fluid clearance assessed by resting-state functional magnetic resonance imaging. Neuroimage 2024; 302:120905. [PMID: 39461604 DOI: 10.1016/j.neuroimage.2024.120905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Revised: 10/22/2024] [Accepted: 10/23/2024] [Indexed: 10/29/2024] Open
Abstract
Cerebrospinal fluid (CSF) flow may assist the clearance of brain wastes, such as amyloid-β (Aβ) and tau, and thus play an important role in aging and dementias. However, a lack of non-invasive tools to assess the CSF dynamics-related clearance in humans hindered the understanding of the relevant changes in healthy aging. The global infra-slow (<0.1 Hz) brain activity measured by the global mean resting-state fMRI signal (gBOLD) was recently found to be coupled by large CSF movements. This coupling has been found to correlate with various pathologies of Alzheimer's disease (AD), particularly Aβ pathology, linking it to waste clearance. Using resting-state fMRI data from a group of 719 healthy aging participants, we examined the sex-specific differences of the gBOLD-CSF coupling over a wide age range between 36-100 years of age. We found that this coupling index remains stable before around age 55 and then starts to decline afterward, particularly in females. Menopause may contribute to the accelerated decline in females.
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Affiliation(s)
- Feng Han
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Xufu Liu
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Yifan Yang
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Xiao Liu
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA; Institute for Computational and Data Sciences, The Pennsylvania State University, PA, USA.
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17
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Chen X, Cramer SR, Chan DC, Han X, Zhang N. Sequential Deactivation Across the Hippocampus-Thalamus-mPFC Pathway During Loss of Consciousness. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2406320. [PMID: 39248326 PMCID: PMC11558098 DOI: 10.1002/advs.202406320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2024] [Revised: 08/12/2024] [Indexed: 09/10/2024]
Abstract
How consciousness is lost in states such as sleep or anesthesia remains a mystery. To gain insight into this phenomenon, concurrent recordings of electrophysiology signals in the anterior cingulate cortex and whole-brain functional magnetic resonance imaging (fMRI) are conducted in rats exposed to graded propofol, undergoing the transition from consciousness to unconsciousness. The results reveal that upon the loss of consciousness (LOC), there is a sharp increase in low-frequency power of the electrophysiological signal. Additionally, fMRI signals exhibit a cascade of deactivation across a pathway including the hippocampus, thalamus, and medial prefrontal cortex (mPFC) surrounding the moment of LOC, followed by a broader increase in brain activity across the cortex during sustained unconsciousness. Furthermore, sliding window analysis demonstrates a temporary increase in synchrony of fMRI signals across the hippocampus-thalamus-mPFC pathway preceding LOC. These data suggest that LOC may be triggered by sequential activities in the hippocampus, thalamus, and mPFC, while wide-spread activity increases in other cortical regions commonly observed during anesthesia-induced unconsciousness may be a consequence, rather than a cause of LOC. Taken together, the study identifies a cascade of neural events unfolding as the brain transitions into unconsciousness, offering insight into the systems-level neural mechanisms underpinning LOC.
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Affiliation(s)
- Xiaoai Chen
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Samuel R. Cramer
- The Neuroscience Graduate ProgramThe Huck Institutes of the Life SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Dennis C.Y. Chan
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Xu Han
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
| | - Nanyin Zhang
- Department of Biomedical EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
- The Neuroscience Graduate ProgramThe Huck Institutes of the Life SciencesThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neurotechnology in Mental Health ResearchThe Pennsylvania State UniversityUniversity ParkPA16802USA
- Center for Neural EngineeringThe Pennsylvania State UniversityUniversity ParkPA16802USA
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18
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Wang X, Padawer-Curry JA, Bice AR, Kim B, Rosenthal ZP, Lee JM, Goyal MS, Macauley SL, Bauer AQ. Spatiotemporal relationships between neuronal, metabolic, and hemodynamic signals in the awake and anesthetized mouse brain. Cell Rep 2024; 43:114723. [PMID: 39277861 PMCID: PMC11523563 DOI: 10.1016/j.celrep.2024.114723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 07/08/2024] [Accepted: 08/21/2024] [Indexed: 09/17/2024] Open
Abstract
Neurovascular coupling (NVC) and neurometabolic coupling (NMC) provide the basis for functional magnetic resonance imaging and positron emission tomography to map brain neurophysiology. While increases in neuronal activity are often accompanied by increases in blood oxygen delivery and oxidative metabolism, these observations are not the rule. This decoupling is important when interpreting brain network organization (e.g., resting-state functional connectivity [RSFC]) because it is unclear whether changes in NMC/NVC affect RSFC measures. We leverage wide-field optical imaging in Thy1-jRGECO1a mice to map cortical calcium activity in pyramidal neurons, flavoprotein autofluorescence (representing oxidative metabolism), and hemodynamic activity during wake and ketamine/xylazine anesthesia. Spontaneous dynamics of all contrasts exhibit patterns consistent with RSFC. NMC/NVC relative to excitatory activity varies over the cortex. Ketamine/xylazine profoundly alters NVC but not NMC. Compared to awake RSFC, ketamine/xylazine affects metabolic-based connectomes moreso than hemodynamic-based measures of RSFC. Anesthesia-related differences in NMC/NVC timing do not appreciably alter RSFC structure.
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Affiliation(s)
- Xiaodan Wang
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | - Jonah A Padawer-Curry
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Imaging Sciences Program, Washington University in Saint Louis, St. Louis, MO 63130, USA
| | - Annie R Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Byungchan Kim
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Zachary P Rosenthal
- Department of Psychiatry, University of Pennsylvania Health System Penn Medicine, Philadelphia, PA 19104, USA
| | - Jin-Moo Lee
- Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA; Department of Neurology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Manu S Goyal
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Shannon L Macauley
- Department of Physiology, University of Kentucky, Lexington, KY 40508, USA
| | - Adam Q Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University in Saint Louis, St. Louis, MO 63130, USA; Imaging Sciences Program, Washington University in Saint Louis, St. Louis, MO 63130, USA.
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19
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Lewis CM, Hoffmann A, Helmchen F. Linking brain activity across scales with simultaneous opto- and electrophysiology. NEUROPHOTONICS 2024; 11:033403. [PMID: 37662552 PMCID: PMC10472193 DOI: 10.1117/1.nph.11.3.033403] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 07/19/2023] [Accepted: 07/24/2023] [Indexed: 09/05/2023]
Abstract
The brain enables adaptive behavior via the dynamic coordination of diverse neuronal signals across spatial and temporal scales: from fast action potential patterns in microcircuits to slower patterns of distributed activity in brain-wide networks. Understanding principles of multiscale dynamics requires simultaneous monitoring of signals in multiple, distributed network nodes. Combining optical and electrical recordings of brain activity is promising for collecting data across multiple scales and can reveal aspects of coordinated dynamics invisible to standard, single-modality approaches. We review recent progress in combining opto- and electrophysiology, focusing on mouse studies that shed new light on the function of single neurons by embedding their activity in the context of brain-wide activity patterns. Optical and electrical readouts can be tailored to desired scales to tackle specific questions. For example, fast dynamics in single cells or local populations recorded with multi-electrode arrays can be related to simultaneously acquired optical signals that report activity in specified subpopulations of neurons, in non-neuronal cells, or in neuromodulatory pathways. Conversely, two-photon imaging can be used to densely monitor activity in local circuits while sampling electrical activity in distant brain areas at the same time. The refinement of combined approaches will continue to reveal previously inaccessible and under-appreciated aspects of coordinated brain activity.
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Affiliation(s)
| | - Adrian Hoffmann
- University of Zurich, Brain Research Institute, Zurich, Switzerland
- University of Zurich, Neuroscience Center Zurich, Zurich, Switzerland
| | - Fritjof Helmchen
- University of Zurich, Brain Research Institute, Zurich, Switzerland
- University of Zurich, Neuroscience Center Zurich, Zurich, Switzerland
- University of Zurich, University Research Priority Program, Adaptive Brain Circuits in Development and Learning, Zurich, Switzerland
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20
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Deng S, Hu Y, Chen S, Xue Y, Yao D, Sun Q, Nedergaard M, Wang W, Ding F. Chronic sleep fragmentation impairs brain interstitial clearance in young wildtype mice. J Cereb Blood Flow Metab 2024; 44:1515-1531. [PMID: 38639025 PMCID: PMC11418708 DOI: 10.1177/0271678x241230188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/06/2023] [Accepted: 12/27/2023] [Indexed: 04/20/2024]
Abstract
Accumulating evidence shows that most chronic neurological diseases have a link with sleep disturbances, and that patients with chronically poor sleep undergo an accelerated cognitive decline. Indeed, a single-night of sleep deprivation may increase metabolic waste levels in cerebrospinal fluid. However, it remains unknown how chronic sleep disturbances in isolation from an underlying neurological disease may affect the glymphatic system. Clearance of brain interstitial waste by the glymphatic system occurs primarily during sleep, driven by multiple oscillators including arterial pulsatility, and vasomotion. Herein, we induced sleep fragmentation in young wildtype mice and assessed the effects on glymphatic activity and cognitive functions. Chronic sleep fragmentation reduced glymphatic function and impaired cognitive functions in healthy mice. A mechanistic analysis showed that the chronic sleep fragmentation suppressed slow vasomotion, without altering cardiac-driven pulsations. Taken together, results of this study document that chronic sleep fragmentation suppresses brain metabolite clearance and impairs cognition, even in the absence of disease.
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Affiliation(s)
- Saiyue Deng
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yusi Hu
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Simiao Chen
- Department of Rehabilitation Medicine, First Affiliated Hospital, Zhejiang University, Hangzhou, 310003, China
| | - Yang Xue
- Department of Neurology, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Di Yao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qian Sun
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Department of Neurology, University of Rochester Medical Center, Rochester, NY, 14642, United States
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Copenhagen, Copenhagen 2200, Denmark
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Fengfei Ding
- Department of Pharmacology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
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21
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Ge GR, Song W, Giannetto MJ, Rolland JP, Nedergaard M, Parker KJ. Mouse brain elastography changes with sleep/wake cycles, aging, and Alzheimer's disease. Neuroimage 2024; 295:120662. [PMID: 38823503 PMCID: PMC11409907 DOI: 10.1016/j.neuroimage.2024.120662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/05/2024] [Accepted: 05/30/2024] [Indexed: 06/03/2024] Open
Abstract
Understanding the physiological processes in aging and how neurodegenerative disorders affect cognitive function is a high priority for advancing human health. One specific area of recently enabled research is the in vivo biomechanical state of the brain. This study utilized reverberant optical coherence elastography, a high-resolution elasticity imaging method, to investigate stiffness changes during the sleep/wake cycle, aging, and Alzheimer's disease in murine models. Four-dimensional scans of 44 wildtype mice, 13 mice with deletion of aquaporin-4 water channel, and 12 mice with Alzheimer-related pathology (APP/PS1) demonstrated that (1) cortical tissue became softer (on the order of a 10% decrease in shear wave speed) when young wildtype mice transitioned from wake to anesthetized, yet this effect was lost in aging and with mice overexpressing amyloid-β or lacking the water channel AQP4. (2) Cortical stiffness increased with age in all mice lines, but wildtype mice exhibited the most prominent changes as a function of aging. The study provides novel insight into the brain's biomechanics, the constraints of fluid flow, and how the state of brain activity affects basic properties of cortical tissues.
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Affiliation(s)
- Gary R Ge
- The Institute of Optics, University of Rochester, 480 Intercampus Drive, Rochester, NY 14627, USA
| | - Wei Song
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
| | - Jannick P Rolland
- The Institute of Optics, University of Rochester, 480 Intercampus Drive, Rochester, NY 14627, USA; Department of Biomedical Engineering, University of Rochester, 204 Robert B. Goergen Hall, Rochester, NY 14627, USA; Center for Visual Science, University of Rochester, 361 Meliora Hall, Rochester, NY 14627, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA; Center for Translational Neuromedicine, University of Copenhagen, Blegdamsvej 3B, 2200-N, Denmark.
| | - Kevin J Parker
- Department of Biomedical Engineering, University of Rochester, 204 Robert B. Goergen Hall, Rochester, NY 14627, USA; Department of Electrical and Computer Engineering, University of Rochester, 500 Computer Studies Building, Rochester, NY 14627, USA; Department of Imaging Sciences (Radiology), University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
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Sharon O, Ben Simon E, Shah VD, Desel T, Walker MP. The new science of sleep: From cells to large-scale societies. PLoS Biol 2024; 22:e3002684. [PMID: 38976664 PMCID: PMC11230563 DOI: 10.1371/journal.pbio.3002684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2024] Open
Abstract
In the past 20 years, more remarkable revelations about sleep and its varied functions have arguably been made than in the previous 200. Building on this swell of recent findings, this essay provides a broad sampling of selected research highlights across genetic, molecular, cellular, and physiological systems within the body, networks within the brain, and large-scale social dynamics. Based on this raft of exciting new discoveries, we have come to realize that sleep, in this moment of its evolution, is very much polyfunctional (rather than monofunctional), yet polyfunctional for reasons we had never previously considered. Moreover, these new polyfunctional insights powerfully reaffirm sleep as a critical biological, and thus health-sustaining, requisite. Indeed, perhaps the only thing more impressive than the unanticipated nature of these newly emerging sleep functions is their striking divergence, from operations of molecular mechanisms inside cells to entire group societal dynamics.
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Affiliation(s)
- Omer Sharon
- Department of Psychology, University of California, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Eti Ben Simon
- Department of Psychology, University of California, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Vyoma D. Shah
- Department of Psychology, University of California, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Tenzin Desel
- Department of Psychology, University of California, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
| | - Matthew P. Walker
- Department of Psychology, University of California, Berkeley, California, United States of America
- Helen Wills Neuroscience Institute, University of California, Berkeley, California, United States of America
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Chen X, Cramer SR, Chan DCY, Han X, Zhang N. Sequential deactivation across the thalamus-hippocampus-mPFC pathway during loss of consciousness. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.594986. [PMID: 38826282 PMCID: PMC11142108 DOI: 10.1101/2024.05.20.594986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
How consciousness is lost in states such as sleep or anesthesia remains a mystery. To gain insight into this phenomenon, we conducted concurrent recordings of electrophysiology signals in the anterior cingulate cortex and whole-brain functional magnetic resonance imaging (fMRI) in rats exposed to graded propofol, undergoing the transition from consciousness to unconsciousness. Our results reveal that upon the loss of consciousness (LOC), as indicated by the loss of righting reflex, there is a sharp increase in low-frequency power of the electrophysiological signal. Additionally, simultaneously measured fMRI signals exhibit a cascade of deactivation across a pathway including the hippocampus, thalamus, and medial prefrontal cortex (mPFC) surrounding the moment of LOC, followed by a broader increase in brain activity across the cortex during sustained unconsciousness. Furthermore, sliding window analysis demonstrates a temporary increase in synchrony of fMRI signals across the hippocampus-thalamus-mPFC pathway preceding LOC. These data suggest that LOC might be triggered by sequential activities in the hippocampus, thalamus and mPFC, while wide-spread activity increases in other cortical regions commonly observed during anesthesia-induced unconsciousness might be a consequence, rather than a cause of LOC. Taken together, our study identifies a cascade of neural events unfolding as the brain transitions into unconsciousness, offering critical insight into the systems-level neural mechanisms underpinning LOC.
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24
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Kozberg MG, Munting LP, Maresco LH, Auger CA, van den Berg ML, Denis de Senneville B, Hirschler L, Warnking JM, Barbier EL, Farrar CT, Greenberg SM, Bacskai BJ, van Veluw SJ. Loss of spontaneous vasomotion precedes impaired cerebrovascular reactivity and microbleeds in a mouse model of cerebral amyloid angiopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.26.591414. [PMID: 38746419 PMCID: PMC11092483 DOI: 10.1101/2024.04.26.591414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Background Cerebral amyloid angiopathy (CAA) is a cerebral small vessel disease in which amyloid-β accumulates in vessel walls. CAA is a leading cause of symptomatic lobar intracerebral hemorrhage and an important contributor to age-related cognitive decline. Recent work has suggested that vascular dysfunction may precede symptomatic stages of CAA, and that spontaneous slow oscillations in arteriolar diameter (termed vasomotion), important for amyloid-β clearance, may be impaired in CAA. Methods To systematically study the progression of vascular dysfunction in CAA, we used the APP23 mouse model of amyloidosis, which is known to develop spontaneous cerebral microbleeds mimicking human CAA. Using in vivo 2-photon microscopy, we longitudinally imaged unanesthetized APP23 transgenic mice and wildtype littermates from 7 to 14 months of age, tracking amyloid-β accumulation and vasomotion in individual pial arterioles over time. MRI was used in separate groups of 12-, 18-, and 24-month-old APP23 transgenic mice and wildtype littermates to detect microbleeds and to assess cerebral blood flow and cerebrovascular reactivity with pseudo-continuous arterial spin labeling. Results We observed a significant decline in vasomotion with age in APP23 mice, while vasomotion remained unchanged in wildtype mice with age. This decline corresponded in timing to initial vascular amyloid-β deposition (∼8-10 months of age), although was more strongly correlated with age than with vascular amyloid-β burden in individual arterioles. Declines in vasomotion preceded the development of MRI-visible microbleeds and the loss of smooth muscle actin in arterioles, both of which were observed in APP23 mice by 18 months of age. Additionally, evoked cerebrovascular reactivity was intact in APP23 mice at 12 months of age, but significantly lower in APP23 mice by 24 months of age. Conclusions Our findings suggest that a decline in spontaneous vasomotion is an early, potentially pre-symptomatic, manifestation of CAA and vascular dysfunction, and a possible future treatment target.
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25
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Ruff CF, Juarez Anaya F, Dienel SJ, Rakymzhan A, Altamirano-Espinoza A, Couey JJ, Fukuda M, Watson AM, Su A, Fish KN, Rubio ME, Hooks BM, Ross SE, Vazquez AL. Long-range inhibitory neurons mediate cortical neurovascular coupling. Cell Rep 2024; 43:113970. [PMID: 38512868 PMCID: PMC11168451 DOI: 10.1016/j.celrep.2024.113970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/29/2023] [Accepted: 02/29/2024] [Indexed: 03/23/2024] Open
Abstract
To meet the high energy demands of brain function, cerebral blood flow (CBF) parallels changes in neuronal activity by a mechanism known as neurovascular coupling (NVC). However, which neurons play a role in mediating NVC is not well understood. Here, we identify in mice and humans a specific population of cortical GABAergic neurons that co-express neuronal nitric oxide synthase and tachykinin receptor 1 (Tacr1). Through whole-tissue clearing, we demonstrate that Tacr1 neurons extend local and long-range projections across functionally connected cortical areas. We show that whisker stimulation elicited Tacr1 neuron activity in the barrel cortex through feedforward excitatory pathways. Additionally, through optogenetic experiments, we demonstrate that Tacr1 neurons are instrumental in mediating CBF through the relaxation of mural cells in a similar fashion to whisker stimulation. Finally, by electron microscopy, we observe that Tacr1 processes contact astrocytic endfeet. These findings suggest that Tacr1 neurons integrate cortical activity to mediate NVC.
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Affiliation(s)
- Catherine F Ruff
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Samuel J Dienel
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adiya Rakymzhan
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Jonathan J Couey
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alan M Watson
- Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aihua Su
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Kenneth N Fish
- Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Maria E Rubio
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Bryan M Hooks
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Sarah E Ross
- Department of Neurobiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Alberto L Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
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26
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Avilez-Avilez JJ, Medina-Flores MF, Gómez-Gonzalez B. Sleep loss impairs blood-brain barrier function: Cellular and molecular mechanisms. VITAMINS AND HORMONES 2024; 126:77-96. [PMID: 39029977 DOI: 10.1016/bs.vh.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
Sleep is a physiological process that preserves the integrity of the neuro-immune-endocrine network to maintain homeostasis. Sleep regulates the production and secretion of hormones, neurotransmitters, cytokines and other inflammatory mediators, both at the central nervous system (CNS) and at the periphery. Sleep promotes the removal of potentially toxic metabolites out of the brain through specialized systems such as the glymphatic system, as well as the expression of specific transporters in the blood-brain barrier. The blood-brain barrier maintains CNS homeostasis by selectively transporting metabolic substrates and nutrients into the brain, by regulating the efflux of metabolic waste products, and maintaining bidirectional communication between the periphery and the CNS. All those processes are disrupted during sleep loss. Brain endothelial cells express the blood-brain barrier phenotype, which arises after cell-to-cell interactions with mural cells, like pericytes, and after the release of soluble factors by astroglial endfeet. Astroglia, pericytes and brain endothelial cells respond differently to sleep loss; evidence has shown that sleep loss induces a chronic low-grade inflammatory state at the CNS, which is associated with blood-brain barrier dysfunction. In animal models, blood-brain barrier dysfunction is characterized by increased blood-brain barrier permeability, decreased tight junction protein expression and pericyte detachment from the capillary wall. Blood-brain barrier dysfunction may promote defects in brain clearance of potentially neurotoxic metabolites and byproducts of neural physiology, which may eventually contribute to neurodegenerative diseases. This chapter aims to describe the cellular and molecular mechanisms by which sleep loss modifies the function of the blood-brain barrier.
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Affiliation(s)
- Jessica Janeth Avilez-Avilez
- Graduate Program in Experimental Biology, Universidad Autónoma Metropolitana, Mexico City, Mexico; Area of Neurosciences, Department of Biology of Reproduction, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - María Fernanda Medina-Flores
- Graduate Program in Experimental Biology, Universidad Autónoma Metropolitana, Mexico City, Mexico; Area of Neurosciences, Department of Biology of Reproduction, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Beatriz Gómez-Gonzalez
- Area of Neurosciences, Department of Biology of Reproduction, Universidad Autónoma Metropolitana, Mexico City, Mexico.
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27
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White BR, Adepoju TE, Fisher HB, Shinohara RT, Vandekar S. Spatial nonstationarity of image noise in widefield optical imaging and its effects on cluster-based inference for resting-state functional connectivity. J Neurosci Methods 2024; 404:110076. [PMID: 38331258 PMCID: PMC10940215 DOI: 10.1016/j.jneumeth.2024.110076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2024] [Accepted: 02/04/2024] [Indexed: 02/10/2024]
Abstract
BACKGROUND Resting-state functional connectivity (RSFC) analysis with widefield optical imaging (WOI) is a potentially powerful tool to develop imaging biomarkers in mouse models of disease before translating them to human neuroimaging with functional magnetic resonance imaging (fMRI). The delineation of such biomarkers depends on rigorous statistical analysis. However, statistical understanding of WOI data is limited. In particular, cluster-based analysis of neuroimaging data depends on assumptions of spatial stationarity (i.e., that the distribution of cluster sizes under the null is equal at all brain locations). Whether actual data deviate from this assumption has not previously been examined in WOI. NEW METHOD In this manuscript, we characterize the effects of spatial nonstationarity in WOI RSFC data and adapt a "two-pass" technique from fMRI to correct cluster sizes and mitigate spatial bias, both parametrically and nonparametrically. These methods are tested on multi-institutional data. RESULTS AND COMPARISON WITH EXISTING METHODS We find that spatial nonstationarity has a substantial effect on inference in WOI RSFC data with false positives much more likely at some brain regions than others. This pattern of bias varies between imaging systems, contrasts, and mouse ages, all of which could affect experimental reproducibility if not accounted for. CONCLUSIONS Both parametric and nonparametric corrections for nonstationarity result in significant improvements in spatial bias. The proposed methods are simple to implement and will improve the robustness of inference in optical neuroimaging data.
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Affiliation(s)
- Brian R White
- Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Division of Cardiology, Department of Pediatrics, USA.
| | - Temilola E Adepoju
- Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Division of Cardiology, Department of Pediatrics, USA
| | - Hayden B Fisher
- Children's Hospital of Philadelphia, Perelman School of Medicine at the University of Pennsylvania, Division of Cardiology, Department of Pediatrics, USA
| | - Russell T Shinohara
- University of Pennsylvania, Perelman School of Medicine, Department of Biostatistics, Epidemiology, and Informatics, USA; University of Pennsylvania, Center for Biomedical Image Computing and Analysis, Department of Radiology, USA; University of Pennsylvania, Penn Statistics in Imaging and Visualization Endeavor, Department of Biostatistics, Epidemiology, and Informatics, USA
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28
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Beinlich FR, Asiminas A, Untiet V, Bojarowska Z, Plá V, Sigurdsson B, Timmel V, Gehrig L, Graber MH, Hirase H, Nedergaard M. Oxygen imaging of hypoxic pockets in the mouse cerebral cortex. Science 2024; 383:1471-1478. [PMID: 38547288 PMCID: PMC11251491 DOI: 10.1126/science.adn1011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 02/23/2024] [Indexed: 04/02/2024]
Abstract
Consciousness is lost within seconds upon cessation of cerebral blood flow. The brain cannot store oxygen, and interruption of oxidative phosphorylation is fatal within minutes. Yet only rudimentary knowledge exists regarding cortical partial oxygen tension (Po2) dynamics under physiological conditions. Here we introduce Green enhanced Nano-lantern (GeNL), a genetically encoded bioluminescent oxygen indicator for Po2 imaging. In awake behaving mice, we uncover the existence of spontaneous, spatially defined "hypoxic pockets" and demonstrate their linkage to the abrogation of local capillary flow. Exercise reduced the burden of hypoxic pockets by 52% compared with rest. The study provides insight into cortical oxygen dynamics in awake behaving animals and concurrently establishes a tool to delineate the importance of oxygen tension in physiological processes and neurological diseases.
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Affiliation(s)
- Felix R.M. Beinlich
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Antonios Asiminas
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Verena Untiet
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Zuzanna Bojarowska
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Virginia Plá
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Björn Sigurdsson
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
| | - Vincenzo Timmel
- School of Engineering, FHNW University of Applied Sciences and Arts Northwestern Switzerland; 5210 Windisch, Switzerland
| | - Lukas Gehrig
- School of Engineering, FHNW University of Applied Sciences and Arts Northwestern Switzerland; 5210 Windisch, Switzerland
| | - Michael H. Graber
- School of Engineering, FHNW University of Applied Sciences and Arts Northwestern Switzerland; 5210 Windisch, Switzerland
| | - Hajime Hirase
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center; Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen; 2200 Copenhagen, Denmark
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center; Rochester, NY 14642, USA
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29
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Tao MX, Meng L, Xie WY, Li HX, Zhang JR, Yan JH, Cheng XY, Wang F, Mao CJ, Shen Y, Liu CF. Slow-wave sleep and REM sleep without atonia predict motor progression in Parkinson's disease. Sleep Med 2024; 115:155-161. [PMID: 38367357 DOI: 10.1016/j.sleep.2024.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/01/2024] [Accepted: 02/01/2024] [Indexed: 02/19/2024]
Abstract
BACKGROUND Growing evidence supports the potential role of sleep in the motor progression of Parkinson's disease (PD). Slow-wave sleep (SWS) and rapid eye movement (REM) sleep without atonia (RWA) are important sleep parameters. The association between SWS and RWA with PD motor progression and their predictive value have not yet been elucidated. METHODS We retro-prospectively analyzed clinical and polysomnographic data of 136 patients with PD. The motor symptoms were assessed using Unified Parkinson's Disease Rating Scale Part III (UPDRS III) at baseline and follow-up to determine its progression. Partial correlation analysis was used to explore the cross-sectional associations between slow-wave energy (SWE), RWA and clinical symptoms. Longitudinal analyses were performed using Cox regression and linear mixed-effects models. RESULTS Among 136 PD participants, cross-sectional partial correlation analysis showed SWE decreased with the prolongation of the disease course (P = 0.046), RWA density was positively correlated with Hoehn & Yahr (H-Y) stage (tonic RWA, P < 0.001; phasic RWA, P = 0.002). Cox regression analysis confirmed that low SWE (HR = 1.739, 95% CI = 1.038-2.914; P = 0.036; FDR-P = 0.036) and high tonic RWA (HR = 0.575, 95% CI = 0.343-0.963; P = 0.032; FDR-P = 0.036) were predictors of motor symptom progression. Furthermore, we found that lower SWE predicted faster rate of axial motor progression (P < 0.001; FDR-P < 0.001) while higher tonic RWA density was associated with faster rate of rigidity progression (P = 0.006; FDR-P = 0.024) using linear mixed-effects models. CONCLUSIONS These findings suggest that SWS and RWA might represent markers of different motor subtypes progression in PD.
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Affiliation(s)
- Meng-Xing Tao
- Department of Neurology, Second Hospital Affiliated of Xinjiang Medical University, Ürümqi, 830063, Xinjiang, China; Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Lin Meng
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Wei-Ye Xie
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Han-Xing Li
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Jin-Ru Zhang
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Jia-Hui Yan
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Xiao-Yu Cheng
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Fen Wang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Cheng-Jie Mao
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Yun Shen
- Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China.
| | - Chun-Feng Liu
- Department of Neurology, Second Hospital Affiliated of Xinjiang Medical University, Ürümqi, 830063, Xinjiang, China; Department of Neurology and Clinical Research Center of Neurological Disease, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China; Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience, Soochow University, Suzhou, 215123, China.
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30
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Green TRF, Carey SD, Mannino G, Craig JA, Rowe RK, Zielinski MR. Sleep, inflammation, and hemodynamics in rodent models of traumatic brain injury. Front Neurosci 2024; 18:1361014. [PMID: 38426017 PMCID: PMC10903352 DOI: 10.3389/fnins.2024.1361014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 01/29/2024] [Indexed: 03/02/2024] Open
Abstract
Traumatic brain injury (TBI) can induce dysregulation of sleep. Sleep disturbances include hypersomnia and hyposomnia, sleep fragmentation, difficulty falling asleep, and altered electroencephalograms. TBI results in inflammation and altered hemodynamics, such as changes in blood brain barrier permeability and cerebral blood flow. Both inflammation and altered hemodynamics, which are known sleep regulators, contribute to sleep impairments post-TBI. TBIs are heterogenous in cause and biomechanics, which leads to different molecular and symptomatic outcomes. Animal models of TBI have been developed to model the heterogeneity of TBIs observed in the clinic. This review discusses the intricate relationship between sleep, inflammation, and hemodynamics in pre-clinical rodent models of TBI.
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Affiliation(s)
- Tabitha R. F. Green
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States
| | - Sean D. Carey
- Veterans Affairs (VA) Boston Healthcare System, West Roxbury, MA, United States
- Department of Psychiatry, Harvard Medical School, West Roxbury, MA, United States
| | - Grant Mannino
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States
| | - John A. Craig
- Veterans Affairs (VA) Boston Healthcare System, West Roxbury, MA, United States
| | - Rachel K. Rowe
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States
| | - Mark R. Zielinski
- Veterans Affairs (VA) Boston Healthcare System, West Roxbury, MA, United States
- Department of Psychiatry, Harvard Medical School, West Roxbury, MA, United States
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31
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Ungurean G, Rattenborg NC. A mammal and bird's-eye-view of the pupil during sleep and wakefulness. Eur J Neurosci 2024; 59:584-594. [PMID: 37038095 DOI: 10.1111/ejn.15983] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/03/2023] [Accepted: 03/30/2023] [Indexed: 04/12/2023]
Abstract
Besides regulating the amount of light that reaches the retina, fluctuations in pupil size also occur in isoluminant conditions during accommodation, during movement and in relation to cognitive workload, attention and emotion. Recent studies in mammals and birds revealed that the pupils are also highly dynamic in the dark during sleep. However, despite exhibiting similar sleep states (rapid eye movement [REM] and non-REM [NREM] sleep), wake and sleep state-dependent changes in pupil size are opposite between mammals and birds, due in part to differences in the type (striated vs. smooth) and control of the iris muscles. Given the link between pupil dynamics and cognitive processes occurring during wakefulness, sleep-related changes in pupil size might indicate when related processes are occurring during sleep. Moreover, the divergent pupillary behaviour observed between mammals and birds raises the possibility that changes in pupil size in birds are a readout of processes not reflected in the mammalian pupil.
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Affiliation(s)
- Gianina Ungurean
- Max Planck Institute for Biological Intelligence, Seewiesen, Germany
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32
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Wang ZJ, Lee HC, Chuang CH, Hsiao FC, Lee SH, Hsu AL, Wu CW. Traces of EEG-fMRI coupling reveals neurovascular dynamics on sleep inertia. Sci Rep 2024; 14:1537. [PMID: 38233587 PMCID: PMC10794702 DOI: 10.1038/s41598-024-51694-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Accepted: 01/08/2024] [Indexed: 01/19/2024] Open
Abstract
Upon emergence from sleep, individuals experience temporary hypo-vigilance and grogginess known as sleep inertia. During the transient period of vigilance recovery from prior nocturnal sleep, the neurovascular coupling (NVC) may not be static and constant as assumed by previous neuroimaging studies. Stemming from this viewpoint of sleep inertia, this study aims to probe the NVC changes as awakening time prolongs using simultaneous EEG-fMRI. The time-lagged coupling between EEG features of vigilance and BOLD-fMRI signals, in selected regions of interest, was calculated with one pre-sleep and three consecutive post-awakening resting-state measures. We found marginal changes in EEG theta/beta ratio and spectral slope across post-awakening sessions, demonstrating alterations of vigilance during sleep inertia. Time-varying EEG-fMRI coupling as awakening prolonged was evidenced by the changing time lags of the peak correlation between EEG alpha-vigilance and fMRI-thalamus, as well as EEG spectral slope and fMRI-anterior cingulate cortex. This study provides the first evidence of potential dynamicity of NVC occurred in sleep inertia and opens new avenues for non-invasive neuroimaging investigations into the neurophysiological mechanisms underlying brain state transitions.
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Affiliation(s)
- Zhitong John Wang
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, 5 Floor, 301, Yuantong Rd., Zhonghe Dist, New Taipei, 235040, Taiwan
| | - Hsin-Chien Lee
- Department of Psychiatry, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Research Center of Sleep Medicine, Taipei Medical University Hospital, Taipei, Taiwan
| | - Chun-Hsiang Chuang
- Research Center for Education and Mind Sciences, College of Education, National Tsing Hua University, Hsinchu, Taiwan
| | - Fan-Chi Hsiao
- Department of Counseling, Clinical and Industrial/Organizational Psychology, Ming Chuan University, Taoyuan, Taiwan
| | - Shwu-Hua Lee
- Department of Psychiatry, Chang Gung Memorial Hospital at Linkou, 259, Wenhua 1St Rd., Guishan Dist., Taoyuan, 33302, Taiwan
- School of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ai-Ling Hsu
- Department of Psychiatry, Chang Gung Memorial Hospital at Linkou, 259, Wenhua 1St Rd., Guishan Dist., Taoyuan, 33302, Taiwan.
- Bachelor Program in Artificial Intelligence, Chang Gung University, Taoyuan, Taiwan.
| | - Changwei W Wu
- Graduate Institute of Mind, Brain and Consciousness, Taipei Medical University, 5 Floor, 301, Yuantong Rd., Zhonghe Dist, New Taipei, 235040, Taiwan.
- Research Center of Sleep Medicine, Taipei Medical University Hospital, Taipei, Taiwan.
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Miyakoshi LM, Stæger FF, Li Q, Pan C, Xie L, Kang H, Pavan C, Dang J, Sun Q, Ertürk A, Nedergaard M. The state of brain activity modulates cerebrospinal fluid transport. Prog Neurobiol 2023; 229:102512. [PMID: 37482196 DOI: 10.1016/j.pneurobio.2023.102512] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/13/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023]
Abstract
Earlier studies based on 2-photon imaging have shown that glymphatic cerebrospinal fluid (CSF) transport is regulated by the sleep-wake cycle. To examine this association, we used 3DISCO whole-body tissue clearing to map CSF tracer distribution in awake, sleeping and ketamine-xylazine anesthetized mice. The results of our analysis showed that CSF tracers entered the brain to a significantly larger extent in natural sleep or ketamine-xylazine anesthesia than in wakefulness. Furthermore, awake mice showed preferential transport of CSF tracers in the rostro-caudal direction towards the cervical and spinal cord lymphatic vessels, and hence to venous circulation and excretion by the kidneys. The study extends the current literature by showing that CSF dynamics on the whole-body scale is controlled by the state of brain activity.
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Affiliation(s)
- Leo M Miyakoshi
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Frederik F Stæger
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Qianliang Li
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Chenchen Pan
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center Munich, Neuherberg, Germany; Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians University Munich, Munich, Germany
| | - Lulu Xie
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hongyi Kang
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Chiara Pavan
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Juliana Dang
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Qian Sun
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Ali Ertürk
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center Munich, Neuherberg, Germany; Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians University Munich, Munich, Germany
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark; Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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Aframian K, Yousef Yengej D, Nwaobi S, Raman S, Faas GC, Charles A. Effects of chronic caffeine on patterns of brain blood flow and behavior throughout the sleep-wake cycle in freely behaving mice. PNAS NEXUS 2023; 2:pgad303. [PMID: 37780231 PMCID: PMC10538474 DOI: 10.1093/pnasnexus/pgad303] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/05/2023] [Indexed: 10/03/2023]
Abstract
Caffeine has significant effects on neurovascular activity and behavior throughout the sleep-wake cycle. We used a minimally invasive microchip/video system to continuously record effects of caffeine in the drinking water of freely behaving mice. Chronic caffeine shifted both rest and active phases by up to 2 h relative to the light-dark cycle in a dose-dependent fashion. There was a particular delay in the onset of rapid eye movement (REM) sleep as compared with non-REM sleep during the rest phase. Chronic caffeine increased wakefulness during the active phase and consolidated sleep during the rest phase; overall, there was no net change in the amount of time spent in the wake, sleep, or REM sleep states during caffeine administration. Despite these effects on wakefulness and sleep, chronic caffeine decreased mean cerebral blood volume (CBV) during the active phase and increased mean CBV during the rest phase. Chronic caffeine also increased heart rate variability in both the sleep and wake states. These results provide new insight into the effects of caffeine on the biology of the sleep-wake cycle. Increased blood flow during sleep caused by chronic caffeine may have implications for its potential neuroprotective effects through vascular mechanisms of brain waste clearance.
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Affiliation(s)
- Kimiya Aframian
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
| | - Dmitri Yousef Yengej
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
| | - Sinifunanya Nwaobi
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
| | - Shrayes Raman
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
| | - Guido C Faas
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
| | - Andrew Charles
- Department of Neurology, David Geffen School of Medicine at UCLA, 635 Charles Young Drive, Los Angeles, CA 90095, USA
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Andersen M, Tsopanidou A, Radovanovic T, Compere VN, Hauglund N, Nedergaard M, Kjaerby C. Using Fiber Photometry in Mice to Estimate Fluorescent Biosensor Levels During Sleep. Bio Protoc 2023; 13:e4734. [PMID: 37575397 PMCID: PMC10415158 DOI: 10.21769/bioprotoc.4734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/12/2023] [Accepted: 05/12/2023] [Indexed: 08/15/2023] Open
Abstract
Sleep is not homogenous but contains a highly diverse microstructural composition influenced by neuromodulators. Prior methods used to measure neuromodulator levels in vivo have been limited by low time resolution or technical difficulties in achieving recordings in a freely moving setting, which is essential for natural sleep. In this protocol, we demonstrate the combination of electroencephalographic (EEG)/electromyographic (EMG) recordings with fiber photometric measurements of fluorescent biosensors for neuromodulators in freely moving mice. This allows for real-time assessment of extracellular neuromodulator levels during distinct phases of sleep with a high temporal resolution.
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Affiliation(s)
- Mie Andersen
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
| | - Anastasia Tsopanidou
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
| | - Tessa Radovanovic
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
| | - Viviane Noelani Compere
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
| | - Natalie Hauglund
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, USA
| | - Celia Kjaerby
- Center for Translational Neuromedicine, University of Copenhagen, Noerre Alle 14, 2200 Copenhagen, Denmark
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Gheres KW, Ünsal HS, Han X, Zhang Q, Turner KL, Zhang N, Drew PJ. Arousal state transitions occlude sensory-evoked neurovascular coupling in neonatal mice. Commun Biol 2023; 6:738. [PMID: 37460780 PMCID: PMC10352318 DOI: 10.1038/s42003-023-05121-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 07/07/2023] [Indexed: 07/20/2023] Open
Abstract
In the adult sensory cortex, increases in neural activity elicited by sensory stimulation usually drive vasodilation mediated by neurovascular coupling. However, whether neurovascular coupling is the same in neonatal animals as adults is controversial, as both canonical and inverted responses have been observed. We investigated the nature of neurovascular coupling in unanesthetized neonatal mice using optical imaging, electrophysiology, and BOLD fMRI. We find in neonatal (postnatal day 15, P15) mice, sensory stimulation induces a small increase in blood volume/BOLD signal, often followed by a large decrease in blood volume. An examination of arousal state of the mice revealed that neonatal mice were asleep a substantial fraction of the time, and that stimulation caused the animal to awaken. As cortical blood volume is much higher during REM and NREM sleep than the awake state, awakening occludes any sensory-evoked neurovascular coupling. When neonatal mice are stimulated during an awake period, they showed relatively normal (but slowed) neurovascular coupling, showing that that the typically observed constriction is due to arousal state changes. These result show that sleep-related vascular changes dominate over any sensory-evoked changes, and hemodynamic measures need to be considered in the context of arousal state changes.
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Affiliation(s)
- Kyle W Gheres
- Molecular Cellular and Integrative Bioscience program, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Hayreddin S Ünsal
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Electrical and Electronics Engineering, Abdullah Gul University, Kayseri, Türkiye
| | - Xu Han
- Molecular Cellular and Integrative Bioscience program, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Kevin L Turner
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Nanyin Zhang
- Molecular Cellular and Integrative Bioscience program, The Pennsylvania State University, University Park, PA, 16802, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
- Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Patrick J Drew
- Molecular Cellular and Integrative Bioscience program, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park, PA, 16802, USA.
- Departments of Neurosurgery and Biology, The Pennsylvania State University, University Park, PA, 16802, USA.
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Ungurean G, Behroozi M, Böger L, Helluy X, Libourel PA, Güntürkün O, Rattenborg NC. Wide-spread brain activation and reduced CSF flow during avian REM sleep. Nat Commun 2023; 14:3259. [PMID: 37277328 DOI: 10.1038/s41467-023-38669-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 05/03/2023] [Indexed: 06/07/2023] Open
Abstract
Mammalian sleep has been implicated in maintaining a healthy extracellular environment in the brain. During wakefulness, neuronal activity leads to the accumulation of toxic proteins, which the glymphatic system is thought to clear by flushing cerebral spinal fluid (CSF) through the brain. In mice, this process occurs during non-rapid eye movement (NREM) sleep. In humans, ventricular CSF flow has also been shown to increase during NREM sleep, as visualized using functional magnetic resonance imaging (fMRI). The link between sleep and CSF flow has not been studied in birds before. Using fMRI of naturally sleeping pigeons, we show that REM sleep, a paradoxical state with wake-like brain activity, is accompanied by the activation of brain regions involved in processing visual information, including optic flow during flight. We further demonstrate that ventricular CSF flow increases during NREM sleep, relative to wakefulness, but drops sharply during REM sleep. Consequently, functions linked to brain activation during REM sleep might come at the expense of waste clearance during NREM sleep.
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Affiliation(s)
- Gianina Ungurean
- Avian Sleep Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany.
| | - Mehdi Behroozi
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany.
| | - Leonard Böger
- Max-Planck Research Group Neural Information Flow, Max Planck Institute for the Neurobiology of Behavior - caesar, Bonn, Germany
- Max-Planck Research Group Genetics of Behaviour, Max Planck Institute for the Neurobiology of Behavior - caesar, Bonn, Germany
| | - Xavier Helluy
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
- Department of Neurophysiology, Medical Faculty, Ruhr-University Bochum, Bochum, Germany
| | - Paul-Antoine Libourel
- CRNL, SLEEP Team, UMR 5292 CNRS/U1028 INSERM, Université Claude Bernard Lyon 1, Lyon, Bron, France
| | - Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
- Research Center One Health Ruhr, Research Alliance Ruhr, Ruhr-University Bochum, Bochum, Germany
| | - Niels C Rattenborg
- Avian Sleep Group, Max Planck Institute for Biological Intelligence, Seewiesen, Germany
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Holstein-Rønsbo S, Gan Y, Giannetto MJ, Rasmussen MK, Sigurdsson B, Beinlich FRM, Rose L, Untiet V, Hablitz LM, Kelley DH, Nedergaard M. Glymphatic influx and clearance are accelerated by neurovascular coupling. Nat Neurosci 2023; 26:1042-1053. [PMID: 37264158 PMCID: PMC10500159 DOI: 10.1038/s41593-023-01327-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 47.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 04/12/2023] [Indexed: 06/03/2023]
Abstract
Functional hyperemia, also known as neurovascular coupling, is a phenomenon that occurs when neural activity increases local cerebral blood flow. Because all biological activity produces metabolic waste, we here sought to investigate the relationship between functional hyperemia and waste clearance via the glymphatic system. The analysis showed that whisker stimulation increased both glymphatic influx and clearance in the mouse somatosensory cortex with a 1.6-fold increase in periarterial cerebrospinal fluid (CSF) influx velocity in the activated hemisphere. Particle tracking velocimetry revealed a direct coupling between arterial dilation/constriction and periarterial CSF flow velocity. Optogenetic manipulation of vascular smooth muscle cells enhanced glymphatic influx in the absence of neural activation. We propose that impedance pumping allows arterial pulsatility to drive CSF in the same direction as blood flow, and we present a simulation that supports this idea. Thus, functional hyperemia boosts not only the supply of metabolites but also the removal of metabolic waste.
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Affiliation(s)
| | - Yiming Gan
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Michael J Giannetto
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Martin Kaag Rasmussen
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | | | - Laura Rose
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Verena Untiet
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester Medical Center, Rochester, NY, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, USA.
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Han F, Liu X, Yang Y, Liu X. Sex-specific age-related changes in glymphatic function assessed by resting-state functional magnetic resonance imaging. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.02.535258. [PMID: 37034667 PMCID: PMC10081329 DOI: 10.1101/2023.04.02.535258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
The glymphatic system that clears out brain wastes, such as amyloid-β (Aβ) and tau, through cerebrospinal fluid (CSF) flow may play an important role in aging and dementias. However, a lack of non-invasive tools to assess the glymphatic function in humans hindered the understanding of the glymphatic changes in healthy aging. The global infra-slow (<0.1 Hz) brain activity measured by the global mean resting-state fMRI signal (gBOLD) was recently found to be coupled by large CSF movements. This coupling has been used to measure the glymphatic process and found to correlate with various pathologies of Alzheimer's disease (AD), including Aβ pathology. Using resting-state fMRI data from a large group of 719 healthy aging participants, we examined the sex-specific changes of the gBOLD-CSF coupling, as a measure of glymphatic function, over a wide age range between 36-100 years old. We found that this coupling index remains stable before around age 55 and then starts to decline afterward, particularly in females. Menopause may contribute to the accelerated decline in females.
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Affiliation(s)
- Feng Han
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Xufu Liu
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Yifan Yang
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
| | - Xiao Liu
- Department of Biomedical Engineering, The Pennsylvania State University, PA, USA
- Institute for Computational and Data Sciences, The Pennsylvania State University, PA, USA
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Yu Y, Qiu Y, Li G, Zhang K, Bo B, Pei M, Ye J, Thompson GJ, Cang J, Fang F, Feng Y, Duan X, Tong C, Liang Z. Sleep fMRI with simultaneous electrophysiology at 9.4 T in male mice. Nat Commun 2023; 14:1651. [PMID: 36964161 PMCID: PMC10039056 DOI: 10.1038/s41467-023-37352-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/14/2023] [Indexed: 03/26/2023] Open
Abstract
Sleep is ubiquitous and essential, but its mechanisms remain unclear. Studies in animals and humans have provided insights of sleep at vastly different spatiotemporal scales. However, challenges remain to integrate local and global information of sleep. Therefore, we developed sleep fMRI based on simultaneous electrophysiology at 9.4 T in male mice. Optimized un-anesthetized mouse fMRI setup allowed manifestation of NREM and REM sleep, and a large sleep fMRI dataset was collected and openly accessible. State dependent global patterns were revealed, and state transitions were found to be global, asymmetrical and sequential, which can be predicted up to 17.8 s using LSTM models. Importantly, sleep fMRI with hippocampal recording revealed potentiated sharp-wave ripple triggered global patterns during NREM than awake state, potentially attributable to co-occurrence of spindle events. To conclude, we established mouse sleep fMRI with simultaneous electrophysiology, and demonstrated its capability by revealing global dynamics of state transitions and neural events.
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Affiliation(s)
- Yalin Yu
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yue Qiu
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Gen Li
- Department of Biomedical Engineering, College of Future Technology, Academy for Advanced Interdisciplinary Studies, National Biomedical Imaging Centre, Peking University, Beijing, China
| | - Kaiwei Zhang
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Binshi Bo
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Mengchao Pei
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Jingjing Ye
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | | | - Jing Cang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Fang Fang
- Department of Anesthesia, Zhongshan Hospital, Fudan University, Shanghai, China
- The Central Hospital of Xuhui District, Shanghai, China
| | - Yanqiu Feng
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China
| | - Xiaojie Duan
- Department of Biomedical Engineering, College of Future Technology, Academy for Advanced Interdisciplinary Studies, National Biomedical Imaging Centre, Peking University, Beijing, China.
| | - Chuanjun Tong
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
- School of Biomedical Engineering, Southern Medical University, Guangzhou, China.
| | - Zhifeng Liang
- Institute of Neuroscience, CAS Key Laboratory of Primate Neurobiology, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, China.
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Zhang Q, Cramer SR, Turner KL, Neuberger T, Drew PJ, Zhang N. High-frequency neuronal signal better explains multi-phase BOLD response. Neuroimage 2023; 268:119887. [PMID: 36681134 PMCID: PMC9962576 DOI: 10.1016/j.neuroimage.2023.119887] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/20/2023] Open
Abstract
Visual stimulation-evoked blood-oxygen-level dependent (BOLD) responses can exhibit more complex temporal dynamics than a simple monophasic response. For instance, BOLD responses sometimes include a phase of positive response followed by a phase of post-stimulus undershoot. Whether the BOLD response during these phases reflects the underlying neuronal signal fluctuations or is contributed by non-neuronal physiological factors remains elusive. When presenting blocks of sustained (i.e. DC) light ON-OFF stimulations to unanesthetized rats, we observed that the response following a decrease in illumination (i.e. OFF stimulation-evoked BOLD response) in the visual cortices displayed reproducible multiple phases, including an initial positive BOLD response, followed by an undershoot and then an overshoot before the next ON trial. This multi-phase BOLD response did not result from the entrainment of the periodic stimulation structure. When we measured the neural correlates of these responses, we found that the high-frequency band from the LFP power (300 - 3000 Hz, multi-unit activity (MUA)), but not the power in the gamma band (30 - 100 Hz) exhibited the same multiphasic dynamics as the BOLD signal. This study suggests that the post-stimulus phases of the BOLD response can be better explained by the high-frequency neuronal signal.
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Affiliation(s)
- Qingqing Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park 16802, USA
| | - Samuel R Cramer
- The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park 16802, USA
| | - Kevin L Turner
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park 16802, USA
| | - Thomas Neuberger
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA
| | - Patrick J Drew
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, USA; The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park 16802, USA; Departments of Engineering Science and Mechanics, Neurosurgery, and Biology, The Pennsylvania State University, University Park, USA
| | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, USA; The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, USA; Center for Neurotechnology in Mental Health Research, The Pennsylvania State University, University Park 16802, USA; Center for Neural Engineering, The Pennsylvania State University, University Park 16802, USA.
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Krishnan B, Tousseyn S, Wang ZI, Murakami H, Wu G, Burgess R, Iasemidis L, Najm I, Alexopoulos AV. Novel noninvasive identification of patient-specific epileptic networks in focal epilepsies: Linking single-photon emission computed tomography perfusion during seizures with resting-state magnetoencephalography dynamics. Hum Brain Mapp 2023; 44:1695-1710. [PMID: 36480260 PMCID: PMC9921232 DOI: 10.1002/hbm.26168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 08/31/2022] [Accepted: 11/18/2022] [Indexed: 12/13/2022] Open
Abstract
Single-photon emission computed tomography (SPECT) during seizures and magnetoencephalography (MEG) during the interictal state are noninvasive modalities employed in the localization of the epileptogenic zone in patients with drug-resistant focal epilepsy (DRFE). The present study aims to investigate whether there exists a preferentially high MEG functional connectivity (FC) among those regions of the brain that exhibit hyperperfusion or hypoperfusion during seizures. We studied MEG and SPECT data in 30 consecutive DRFE patients who had resective epilepsy surgery. We parcellated each ictal perfusion map into 200 regions of interest (ROIs) and generated ROI time series using source modeling of MEG data. FC between ROIs was quantified using coherence and phase-locking value. We defined a generalized linear model to relate the connectivity of each ROI, ictal perfusion z score, and distance between ROIs. We compared the coefficients relating perfusion z score to FC of each ROI and estimated the connectivity within and between resected and unresected ROIs. We found that perfusion z scores were strongly correlated with the FC of hyper-, and separately, hypoperfused ROIs across patients. High interictal connectivity was observed between hyperperfused brain regions inside and outside the resected area. High connectivity was also observed between regions of ictal hypoperfusion. Importantly, the ictally hypoperfused regions had a low interictal connectivity to regions that became hyperperfused during seizures. We conclude that brain regions exhibiting hyperperfusion during seizures highlight a preferentially connected interictal network, whereas regions of ictal hypoperfusion highlight a separate, discrete and interconnected, interictal network.
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Affiliation(s)
- Balu Krishnan
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
| | - Simon Tousseyn
- Academic Center for EpileptologyKempenhaeghe and Maastricht UMC+HeezeThe Netherlands
| | - Zhong Irene Wang
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
| | - Hiroatsu Murakami
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
| | - Guiyun Wu
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
| | - Richard Burgess
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
| | - Leonidas Iasemidis
- Department of Translational NeuroscienceBarrow Neurological InstituteScottsdaleArizonaUSA
- Department of NeurologyBarrow Neurological InstituteScottsdaleArizonaUSA
| | - Imad Najm
- Neurological InstituteEpilepsy Center, Cleveland ClinicClevelandOhioUSA
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Sleep cycle-dependent vascular dynamics in male mice and the predicted effects on perivascular cerebrospinal fluid flow and solute transport. Nat Commun 2023; 14:953. [PMID: 36806170 PMCID: PMC9941497 DOI: 10.1038/s41467-023-36643-5] [Citation(s) in RCA: 64] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 02/01/2023] [Indexed: 02/22/2023] Open
Abstract
Perivascular spaces are important highways for fluid and solute transport in the brain enabling efficient waste clearance during sleep. However, the underlying mechanisms augmenting perivascular flow in sleep are unknown. Using two-photon imaging of naturally sleeping male mice we demonstrate sleep cycle-dependent vascular dynamics of pial arteries and penetrating arterioles: slow, large-amplitude oscillations in NREM sleep, a vasodilation in REM sleep, and a vasoconstriction upon awakening at the end of a sleep cycle and microarousals in NREM and intermediate sleep. These vascular dynamics are mirrored by changes in the size of the perivascular spaces of the penetrating arterioles: slow fluctuations in NREM sleep, reduction in REM sleep and an enlargement upon awakening after REM sleep and during microarousals in NREM and intermediate sleep. By biomechanical modeling we demonstrate that these sleep cycle-dependent perivascular dynamics likely enhance fluid flow and solute transport in perivascular spaces to levels comparable to cardiac pulsation-driven oscillations.
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Gheres KW, Ünsal HS, Han X, Zhang Q, Turner KL, Zhang N, Drew PJ. Arousal state transitions occlude sensory-evoked neurovascular coupling in neonatal mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.18.529057. [PMID: 36824895 PMCID: PMC9949139 DOI: 10.1101/2023.02.18.529057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Abstract
In the adult sensory cortex, increases in neural activity elicited by sensory stimulation usually drives vasodilation mediated by neurovascular coupling. However, whether neurovascular coupling is the same in neonatal animals as adults is controversial, as both canonical and inverted responses have been observed. We investigated the nature of neurovascular coupling in unanesthetized neonatal mice using optical imaging, electrophysiology, and BOLD fMRI. We find in neonatal (postnatal day 15, P15) mice, sensory stimulation induces a small increase in blood volume/BOLD signal, often followed by a large decrease in blood volume. An examination of arousal state of the mice revealed that neonatal mice were asleep a substantial fraction of the time, and that stimulation caused the animal to awaken. As cortical blood volume is much higher during REM and NREM sleep than the awake state, awakening occludes any sensory-evoked neurovascular coupling. When neonatal mice are stimulated during an awake period, they showed relatively normal (but slowed) neurovascular coupling, showing that that the typically observed constriction is due to arousal state changes. These result show that sleep-related vascular changes dominate over any sensory-evoked changes, and hemodynamic measures need to be considered in the context of arousal state changes. Significance Statement In the adult brain, increases in neural activity are often followed by vasodilation, allowing activity to be monitored using optical or magnetic resonance imaging. However, in neonates, sensory stimulation can drive vasoconstriction, whose origin was not understood. We used optical and magnetic resonance imaging approaches to investigate hemodynamics in neonatal mice. We found that sensory-induced vasoconstriction occurred when the mice were asleep, as sleep is associated with dilation of the vasculature of the brain relative to the awake state. The stimulus awakens the mice, causing a constriction due to the arousal state change. Our study shows the importance of monitoring arousal state, particularly when investigating subjects that may sleep, and the dominance arousal effects on brain hemodynamics.
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45
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Turner KL, Gheres KW, Drew PJ. Relating Pupil Diameter and Blinking to Cortical Activity and Hemodynamics across Arousal States. J Neurosci 2023; 43:949-964. [PMID: 36517240 PMCID: PMC9908322 DOI: 10.1523/jneurosci.1244-22.2022] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Arousal state affects neural activity and vascular dynamics in the cortex, with sleep associated with large changes in the local field potential and increases in cortical blood flow. We investigated the relationship between pupil diameter and blink rate with neural activity and blood volume in the somatosensory cortex in male and female unanesthetized, head-fixed mice. We monitored these variables while the mice were awake, during periods of rapid eye movement (REM), and non-rapid eye movement (NREM) sleep. Pupil diameter was smaller during sleep than in the awake state. Changes in pupil diameter were coherent with both gamma-band power and blood volume in the somatosensory cortex, but the strength and sign of this relationship varied with arousal state. We observed a strong negative correlation between pupil diameter and both gamma-band power and blood volume during periods of awake rest and NREM sleep, although the correlations between pupil diameter and these signals became positive during periods of alertness, active whisking, and REM. Blinking was associated with increases in arousal and decreases in blood volume when the mouse was asleep. Bilateral coherence in gamma-band power and in blood volume dropped following awake blinking, indicating a reset of neural and vascular activity. Using only eye metrics (pupil diameter and eye motion), we could determine the arousal state of the mouse ('Awake,' 'NREM,' 'REM') with >90% accuracy with a 5 s resolution. There is a strong relationship between pupil diameter and hemodynamics signals in mice, reflecting the pronounced effects of arousal on cerebrovascular dynamics.SIGNIFICANCE STATEMENT Determining arousal state is a critical component of any neuroscience experiment. Pupil diameter and blinking are influenced by arousal state, as are hemodynamics signals in the cortex. We investigated the relationship between cortical hemodynamics and pupil diameter and found that pupil diameter was strongly related to the blood volume in the cortex. Mice were more likely to be awake after blinking than before, and blinking resets neural activity. Pupil diameter and eye motion can be used as a reliable, noninvasive indicator of arousal state. As mice transition from wake to sleep and back again over a timescale of seconds, monitoring pupil diameter and eye motion permits the noninvasive detection of sleep events during behavioral or resting-state experiments.
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Affiliation(s)
- Kevin L Turner
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
| | - Kyle W Gheres
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Departments of Engineering Science and Mechanics
| | - Patrick J Drew
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Center for Neural Engineering, Pennsylvania State University, University Park, Pennsylvania 16802
- Departments of Engineering Science and Mechanics
- Biology and Neurosurgery, Pennsylvania State University, University Park, Pennsylvania 16802
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46
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Matei M, Bergel A, Pezet S, Tanter M. Global dissociation of the posterior amygdala from the rest of the brain during REM sleep. Commun Biol 2022; 5:1306. [PMID: 36443640 PMCID: PMC9705305 DOI: 10.1038/s42003-022-04257-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 11/14/2022] [Indexed: 11/29/2022] Open
Abstract
Rapid-eye-movement sleep (REMS) or paradoxical sleep is associated with intense neuronal activity, fluctuations in autonomic control, body paralysis and brain-wide hyperemia. The mechanisms and functions of these energy-demanding patterns remain elusive and a global picture of brain activation during REMS is currently missing. In the present work, we performed functional ultrasound imaging on rats over multiple coronal and sagittal brain sections during hundreds of spontaneous REMS episodes to provide the spatiotemporal dynamics of vascular activity in 259 brain regions spanning more than 2/3 of the total brain volume. We first demonstrate a dissociation between basal/midbrain and cortical structures, the first ones sustaining tonic activation during REMS while the others are activated in phasic bouts. Second, we isolated the vascular compartment in our recordings and identified arteries in the anterior part of the brain as strongly involved in the blood supply during REMS episodes. Finally, we report a peculiar activation pattern in the posterior amygdala, which is strikingly disconnected from the rest of the brain during most REMS episodes. This last finding suggests that the amygdala undergoes specific processing during REMS and may be linked to the regulation of emotions and the creation of dream content during this very state.
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Affiliation(s)
- Marta Matei
- grid.15736.360000 0001 1882 0021Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR 8063, Paris Sciences et Lettres research University, Paris, France
| | - Antoine Bergel
- grid.15736.360000 0001 1882 0021Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR 8063, Paris Sciences et Lettres research University, Paris, France
| | - Sophie Pezet
- grid.15736.360000 0001 1882 0021Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR 8063, Paris Sciences et Lettres research University, Paris, France
| | - Mickaël Tanter
- grid.15736.360000 0001 1882 0021Physics for Medicine Paris, Inserm U1273, ESPCI Paris, CNRS UMR 8063, Paris Sciences et Lettres research University, Paris, France
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47
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Zhang Q, Cramer SR, Ma Z, Turner KL, Gheres KW, Liu Y, Drew PJ, Zhang N. Brain-wide ongoing activity is responsible for significant cross-trial BOLD variability. Cereb Cortex 2022; 32:5311-5329. [PMID: 35179203 PMCID: PMC9712744 DOI: 10.1093/cercor/bhac016] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/09/2022] [Accepted: 01/11/2022] [Indexed: 12/27/2022] Open
Abstract
A notorious issue of task-based functional magnetic resonance imaging (fMRI) is its large cross-trial variability. To quantitatively characterize this variability, the blood oxygenation level-dependent (BOLD) signal can be modeled as a linear summation of a stimulation-relevant and an ongoing (i.e. stimulation-irrelevant) component. However, systematic investigation on the spatiotemporal features of the ongoing BOLD component and how these features affect the BOLD response is still lacking. Here we measured fMRI responses to light onsets and light offsets in awake rats. The neuronal response was simultaneously recorded with calcium-based fiber photometry. We established that between-region BOLD signals were highly correlated brain-wide at zero time lag, including regions that did not respond to visual stimulation, suggesting that the ongoing activity co-fluctuates across the brain. Removing this ongoing activity reduced cross-trial variability of the BOLD response by ~30% and increased its coherence with the Ca2+ signal. Additionally, the negative ongoing BOLD activity sometimes dominated over the stimulation-driven response and contributed to the post-stimulation BOLD undershoot. These results suggest that brain-wide ongoing activity is responsible for significant cross-trial BOLD variability, and this component can be reliably quantified and removed to improve the reliability of fMRI response. Importantly, this method can be generalized to virtually all fMRI experiments without changing stimulation paradigms.
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Affiliation(s)
- Qingqing Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
| | - Samuel R Cramer
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, United States
| | - Zilu Ma
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
| | - Kevin L Turner
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
| | - Kyle W Gheres
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Graduate Program in Molecular, Cellular, and Integrative Biosciences, The Pennsylvania State University, University Park, PA 16802, United States
| | - Yikang Liu
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
| | - Patrick J Drew
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, United States
- Graduate Program in Molecular, Cellular, and Integrative Biosciences, The Pennsylvania State University, University Park, PA 16802, United States
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA 16802, United States
- Department of Neurosurgery, The Pennsylvania State University, Hershey, PA 17033, United States
| | - Nanyin Zhang
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA 16802, United States
- The Neuroscience Graduate Program, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, PA 16802, United States
- Graduate Program in Molecular, Cellular, and Integrative Biosciences, The Pennsylvania State University, University Park, PA 16802, United States
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48
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Ge GR, Song W, Nedergaard M, Rolland JP, Parker KJ. Theory of sleep/wake cycles affecting brain elastography. Phys Med Biol 2022; 67:10.1088/1361-6560/ac9e40. [PMID: 36317278 PMCID: PMC9999375 DOI: 10.1088/1361-6560/ac9e40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 10/27/2022] [Indexed: 11/05/2022]
Abstract
As elastography of the brain finds increasing clinical applications, fundamental questions remain about baseline viscoelastic properties of the brainin vivo. Furthermore, the underlying mechanisms of how and why elastographic measures can change over time are still not well understood. To study these issues, reverberant shear wave elastography using an optical coherence tomography scanner is implemented on a mouse model, both under awake conditions and in a sleep state where there are known changes in the glymphatic fluid flow system in the brain. We find that shear wave speed, a measure of stiffness, changes by approximately 12% between the two states, sleep versus awake, in the entire cortical brain imaging volume. Our microchannel flow model of biphasic (fluid plus solid) tissue provides a plausible rheological model based on the fractal branching vascular and perivascular system, plus a second parallel system representing the finer scale glymphatic fluid microchannels. By adjusting the glymphatic system fluid volume proportional to the known sleep/wake changes, we are able to approximately predict the measured shear wave speeds and their change with the state of the glymphatic system. The advantages of this model are that its main parameters are derived from anatomical measures and are linked to other major derivations of branching fluid structures including Murray's Law. The implications for clinical studies are that elastography of the brain is strongly influenced by the regulation or dysregulation of the vascular, perivascular, and glymphatic systems.
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Affiliation(s)
- Gary R Ge
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Wei Song
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645, Rochester, NY 14642, United States of America
| | - Jannick P Rolland
- Institute of Optics, University of Rochester, 480 Intercampus Drive, Box 270186, Rochester, NY 14627, United States of America
| | - Kevin J Parker
- Department of Electrical and Computer Engineering, University of Rochester, 724 Computer Studies Building, Box 270231, Rochester, NY 14627, United States of America
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49
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Zhao L, Tannenbaum A, Bakker ENTP, Benveniste H. Physiology of Glymphatic Solute Transport and Waste Clearance from the Brain. Physiology (Bethesda) 2022; 37:0. [PMID: 35881783 PMCID: PMC9550574 DOI: 10.1152/physiol.00015.2022] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 07/12/2022] [Accepted: 07/20/2022] [Indexed: 12/25/2022] Open
Abstract
This review focuses on the physiology of glymphatic solute transport and waste clearance, using evidence from experimental animal models as well as from human studies. Specific topics addressed include the biophysical characteristics of fluid and solute transport in the central nervous system, glymphatic-lymphatic coupling, as well as the role of cerebrospinal fluid movement for brain waste clearance. We also discuss the current understanding of mechanisms underlying increased waste clearance during sleep.
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Affiliation(s)
- Lucy Zhao
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Allen Tannenbaum
- Departments of Computer Science and Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York City, New York
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Cardiovascular Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
- Department of Biomedical Engineering, Yale School of Medicine, New Haven, Connecticut
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50
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Drew PJ. Neurovascular coupling: motive unknown. Trends Neurosci 2022; 45:809-819. [PMID: 35995628 PMCID: PMC9768528 DOI: 10.1016/j.tins.2022.08.004] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/01/2022] [Accepted: 08/05/2022] [Indexed: 12/13/2022]
Abstract
In the brain, increases in neural activity drive changes in local blood flow via neurovascular coupling. The common explanation for increased blood flow (known as functional hyperemia) is that it supplies the metabolic needs of active neurons. However, there is a large body of evidence that is inconsistent with this idea. Baseline blood flow is adequate to supply oxygen needs even with elevated neural activity. Neurovascular coupling is irregular, absent, or inverted in many brain regions, behavioral states, and conditions. Increases in respiration can increase brain oxygenation without flow changes. Simulations show that given the architecture of the brain vasculature, areas of low blood flow are inescapable and cannot be removed by functional hyperemia. As discussed in this article, potential alternative functions of neurovascular coupling include supplying oxygen for neuromodulator synthesis, brain temperature regulation, signaling to neurons, stabilizing and optimizing the cerebral vascular structure, accommodating the non-Newtonian nature of blood, and driving the production and circulation of cerebrospinal fluid (CSF).
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Affiliation(s)
- Patrick J Drew
- Center for Neural Engineering, Departments of Engineering Science and Mechanics, Neurosurgery, Biology, and Biomedical Engineering, The Pennsylvania State University, W-317 Millennium Science Complex, University Park, PA 16802, USA.
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