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Acland BT, Palanca BJA, Bijsterbosch J, Snyder LH. Gamma-burst cortical activity in awake behaving macaques. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.09.26.559594. [PMID: 37808642 PMCID: PMC10557640 DOI: 10.1101/2023.09.26.559594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/10/2023]
Abstract
Electrophysiological recordings during ketamine anesthesia have revealed a slow alternating pattern of high- and low-frequency activity (a "gamma-burst" pattern) that develops along with the onset of general anesthesia. We examine the role of NMDA receptor antagonism in generating the gamma-burst pattern and the link between gamma-bursts and dissociative anesthesia by comparing the effects of ketamine with those of the highly selective NMDA receptor antagonist CGS 19755 on multi-site intracranial electrophysiology and behavior in rhesus macaques. The data show NMDA antagonism alone drives gamma-burst activity, and that it can do so without causing anesthesia. This supports the expanding consensus that ketamine's anesthetic properties are mediated by mechanisms other than NMDA receptor inhibition.
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2
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Zhong X, Liang Y, Wang X, Lan H, Bai X, Jin L, Guan BO. Free-moving-state microscopic imaging of cerebral oxygenation and hemodynamics with a photoacoustic fiberscope. LIGHT, SCIENCE & APPLICATIONS 2024; 13:5. [PMID: 38163847 PMCID: PMC10758391 DOI: 10.1038/s41377-023-01348-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 11/22/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024]
Abstract
We report the development of a head-mounted photoacoustic fiberscope for cerebral imaging in a freely behaving mouse. The 4.5-gram imaging probe has a 9-µm lateral resolution and 0.2-Hz frame rate over a 1.2-mm wide area. The probe can continuously monitor cerebral oxygenation and hemodynamic responses at single-vessel resolution, showing significantly different cerebrovascular responses to external stimuli under anesthesia and in the freely moving state. For example, when subjected to high-concentration CO2 respiration, enhanced oxygenation to compensate for hypercapnia can be visualized due to cerebral regulation in the freely moving state. Comparative studies exhibit significantly weakened compensation capabilities in obese rodents. This new imaging modality can be used for investigating both normal and pathological cerebrovascular functions and shows great promise for studying cerebral activity, disorders and their treatments.
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Affiliation(s)
- Xiaoxuan Zhong
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Yizhi Liang
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Xiaoyu Wang
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Haoying Lan
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Xue Bai
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China
| | - Long Jin
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.
| | - Bai-Ou Guan
- Guangdong Provincial Key Laboratory of Optical Fiber Sensing and Communications, Institute of Photonics Technology, Jinan University, Guangzhou, 510632, China.
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3
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Saez I, Gu X. Invasive Computational Psychiatry. Biol Psychiatry 2023; 93:661-670. [PMID: 36641365 PMCID: PMC10038930 DOI: 10.1016/j.biopsych.2022.09.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/25/2022] [Accepted: 09/27/2022] [Indexed: 01/16/2023]
Abstract
Computational psychiatry, a relatively new yet prolific field that aims to understand psychiatric disorders with formal theories about the brain, has seen tremendous growth in the past decade. Despite initial excitement, actual progress made by computational psychiatry seems stagnant. Meanwhile, understanding of the human brain has benefited tremendously from recent progress in intracranial neuroscience. Specifically, invasive techniques such as stereotactic electroencephalography, electrocorticography, and deep brain stimulation have provided a unique opportunity to precisely measure and causally modulate neurophysiological activity in the living human brain. In this review, we summarize progress and drawbacks in both computational psychiatry and invasive electrophysiology and propose that their combination presents a highly promising new direction-invasive computational psychiatry. The value of this approach is at least twofold. First, it advances our mechanistic understanding of the neural computations of mental states by providing a spatiotemporally precise depiction of neural activity that is traditionally unattainable using noninvasive techniques with human subjects. Second, it offers a direct and immediate way to modulate brain states through stimulation of algorithmically defined neural regions and circuits (i.e., algorithmic targeting), thus providing both causal and therapeutic insights. We then present depression as a use case where the combination of computational and invasive approaches has already shown initial success. We conclude by outlining future directions as a road map for this exciting new field as well as presenting cautions about issues such as ethical concerns and generalizability of findings.
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Affiliation(s)
- Ignacio Saez
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.
| | - Xiaosi Gu
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, New York; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, New York.
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4
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Dietsch AM, Westemeyer RM, Schultz DH. Brain activity associated with taste stimulation: A mechanism for neuroplastic change? Brain Behav 2023; 13:e2928. [PMID: 36860129 PMCID: PMC10097078 DOI: 10.1002/brb3.2928] [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: 08/04/2022] [Revised: 01/21/2023] [Accepted: 02/08/2023] [Indexed: 03/03/2023] Open
Abstract
PURPOSE Neuroplasticity may be enhanced by increasing brain activation and bloodflow in neural regions relevant to the target behavior. We administered precisely formulated and dosed taste stimuli to determine whether the associated brain activity patterns included areas that underlie swallowing control. METHODS Five taste stimuli (unflavored, sour, sweet-sour, lemon, and orange suspensions) were administered in timing-regulated and temperature-controlled 3 mL doses via a customized pump/tubing system to 21 healthy adults during functional magnetic resonance imaging (fMRI). Whole-brain analyses of fMRI data assessed main effects of taste stimulation as well as differential effects of taste profile. RESULTS Differences in brain activity associated with taste stimulation overall as well as specific stimulus type were observed in key taste and swallowing regions including the orbitofrontal cortex, insula, cingulate, and pre- and postcentral gyri. Overall, taste stimulation elicited increased activation in swallowing-related brain regions compared to unflavored trials. Different patterns of blood oxygen level-dependent (BOLD) signal were noted by taste profile. For most areas, sweet-sour and sour trials elicited increases in BOLD compared to unflavored trials within that region, whereas lemon and orange trials yielded reductions in BOLD. This was despite identical concentrations of citric acid and sweetener in the lemon, orange, and sweet-sour solutions. CONCLUSIONS These results suggest that neural activity in swallowing-relevant regions can be amplified with taste stimuli and may be differentially affected by specific properties within very similar taste profiles. These findings provide critical foundational information for interpreting disparities in previous studies of taste effects on brain activity and swallowing function, defining optimal stimuli to increase brain activity in swallowing-relevant regions, and harnessing taste to enhance neuroplasticity and recovery for persons with swallowing disorders.
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Affiliation(s)
- Angela M Dietsch
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, Nebraska.,Center for Brain, Biology, and Behavior, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Ross M Westemeyer
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, Nebraska
| | - Douglas H Schultz
- Center for Brain, Biology, and Behavior, University of Nebraska-Lincoln, Lincoln, Nebraska.,Department of Psychology, University of Nebraska-Lincoln, Lincoln, Nebraska
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5
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Aksenov DP, Rutila K, Li L, Miller MJ, Gascoigne DA, Serdyukova NA, Doubovikov ED, Linsenmeier RA, Drobyshevsky A. Brain Tissue Oxygen and BOLD fMRI Under Different Levels of Neuronal Activity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1438:3-8. [PMID: 37845431 DOI: 10.1007/978-3-031-42003-0_1] [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: 10/18/2023]
Abstract
Localized increases in neuronal activity are supported by the hemodynamic response, which delivers oxygen to the brain tissue to support synaptic functions, action potentials and other neuronal processes. However, it remains unknown if changes in baseline neuronal activity, which are expected to reflect neuronal metabolic demand, alter the relationship between the local hemodynamic and oxygen behaviour. In order to better characterize this system, we examine here the relationship between brain tissue oxygen (PO2) and hemodynamic responses (BOLD functional MRI) under different levels of neuronal activity. By comparing the stimulus-evoked responses during different levels of baseline neuronal activity, the awake state vs isoflurane anesthesia, we were able to measure how a known change in neuronal demand affected tissue PO2 as well as the hemodynamic response to stimulation. We observed a high correlation between stimulus-evoked PO2 and BOLD responses in the awake state. Moreover, we found that the evoked PO2 and BOLD responses were still present despite the elevated tissue oxygen baseline and decreased baseline of neuronal activity under low concentration isoflurane, and that the magnitudes of these responses decreased by similar proportions but the relationship between these signals was distorted. Our findings point to distortion of the BOLD-PO2 relationship due to anesthesia. The feedback mechanism to adjust the level of brain tissue oxygen, as well as the correlation between BOLD and PO2 responses, are impaired even by a small dose of anesthetics.
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Affiliation(s)
- D P Aksenov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA.
- Department of Anesthesiology, NorthShore University HealthSystem, Evanston, IL, USA.
- University of Chicago, Pritzker School of Medicine, Chicago, IL, USA.
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
| | - K Rutila
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
| | - L Li
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA
| | - M J Miller
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA
| | - D A Gascoigne
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA
| | - N A Serdyukova
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - E D Doubovikov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA
| | - R A Linsenmeier
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - A Drobyshevsky
- University of Chicago, Pritzker School of Medicine, Chicago, IL, USA
- Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, USA
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6
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Harauzov AK, Ivanova LE, Vasiliev PP, Podvigina DN. fMRI Studies of Opponent Interregional Interactions in the Macaca mulatta Brain. J EVOL BIOCHEM PHYS+ 2022. [DOI: 10.1134/s0022093022040068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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7
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Ros T, Michela A, Mayer A, Bellmann A, Vuadens P, Zermatten V, Saj A, Vuilleumier P. Disruption of large-scale electrophysiological networks in stroke patients with visuospatial neglect. Netw Neurosci 2022; 6:69-89. [PMID: 35356193 PMCID: PMC8959119 DOI: 10.1162/netn_a_00210] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Accepted: 09/17/2021] [Indexed: 11/29/2022] Open
Abstract
Stroke frequently produces attentional dysfunctions including symptoms of hemispatial neglect, which is characterized by a breakdown of awareness for the contralesional hemispace. Recent studies with functional MRI (fMRI) suggest that hemineglect patients display abnormal intra- and interhemispheric functional connectivity. However, since stroke is a vascular disorder and fMRI signals remain sensitive to nonneuronal (i.e., vascular) coupling, more direct demonstrations of neural network dysfunction in hemispatial neglect are warranted. Here, we utilize electroencephalogram (EEG) source imaging to uncover differences in resting-state network organization between patients with right hemispheric stroke (N = 15) and age-matched, healthy controls (N = 27), and determine the relationship between hemineglect symptoms and brain network organization. We estimated intra- and interregional differences in cortical communication by calculating the spectral power and amplitude envelope correlations of narrow-band EEG oscillations. We first observed focal frequency-slowing within the right posterior cortical regions, reflected in relative delta/theta power increases and alpha/beta/gamma decreases. Secondly, nodes within the right temporal and parietal cortex consistently displayed anomalous intra- and interhemispheric coupling, stronger in delta and gamma bands, and weaker in theta, alpha, and beta bands. Finally, a significant association was observed between the severity of left-hemispace search deficits (e.g., cancellation test omissions) and reduced functional connectivity within the alpha and beta bands. In sum, our novel results validate the hypothesis of large-scale cortical network disruption following stroke and reinforce the proposal that abnormal brain oscillations may be intimately involved in the pathophysiology of visuospatial neglect. Stroke patients often exhibit a disabling deficit of visual awareness in the hemifield opposite to their brain lesion, known as hemineglect. Recent studies with functional MRI (fMRI) suggest that hemineglect patients display abnormal functional coupling (i.e., connectivity) within and between brain hemispheres. However, since stroke is a vascular disorder and fMRI measures nonneuronal (i.e., vascular) coupling, we here provide direct evidence of neural network dysfunction in hemineglect by using electroencephalogram (EEG) source imaging, which measures the electrical fluctuations of large neuronal populations. Overall, we observed a breakdown of interhemispheric network connectivity within alpha/beta rhythms, which specifically correlated with the degree of patients’ hemispatial errors. The high temporal resolution and frequency content of EEG signals could lead to more sensitive markers and targeted rehabilitation approaches of hemineglect.
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Affiliation(s)
- Tomas Ros
- Department of Neuroscience, University of Geneva, Geneva, Switzerland
- CIBM Center for Biomedical Imaging, Geneva University Hospitals, Geneva, Switzerland
| | - Abele Michela
- Department of Neuroscience, University of Geneva, Geneva, Switzerland
| | - Anaïs Mayer
- Romand Clinic of Readaptation, SUVA, Sion, Switzerland
| | - Anne Bellmann
- Romand Clinic of Readaptation, SUVA, Sion, Switzerland
| | | | | | - Arnaud Saj
- Department of Neuroscience, University of Geneva, Geneva, Switzerland
- Department of Neurology, Geneva University Hospital, Geneva, Switzerland
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8
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Ibarra-Lecue I, Haegens S, Harris AZ. Breaking Down a Rhythm: Dissecting the Mechanisms Underlying Task-Related Neural Oscillations. Front Neural Circuits 2022; 16:846905. [PMID: 35310550 PMCID: PMC8931663 DOI: 10.3389/fncir.2022.846905] [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: 12/31/2021] [Accepted: 02/10/2022] [Indexed: 11/13/2022] Open
Abstract
A century worth of research has linked multiple cognitive, perceptual and behavioral states to various brain oscillations. However, the mechanistic roles and circuit underpinnings of these oscillations remain an area of active study. In this review, we argue that the advent of optogenetic and related systems neuroscience techniques has shifted the field from correlational to causal observations regarding the role of oscillations in brain function. As a result, studying brain rhythms associated with behavior can provide insight at different levels, such as decoding task-relevant information, mapping relevant circuits or determining key proteins involved in rhythmicity. We summarize recent advances in this field, highlighting the methods that are being used for this purpose, and discussing their relative strengths and limitations. We conclude with promising future approaches that will help unravel the functional role of brain rhythms in orchestrating the repertoire of complex behavior.
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Affiliation(s)
- Inés Ibarra-Lecue
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,New York State Psychiatric Institute, New York, NY, United States
| | - Saskia Haegens
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,New York State Psychiatric Institute, New York, NY, United States.,Donders Centre for Cognitive Neuroimaging, Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, Netherlands
| | - Alexander Z Harris
- Department of Psychiatry, College of Physicians and Surgeons, Columbia University, New York, NY, United States.,New York State Psychiatric Institute, New York, NY, United States
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9
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Li JM, Acland BT, Brenner AS, Bentley WJ, Snyder LH. Relationships between correlated spikes, oxygen and LFP in the resting-state primate. Neuroimage 2021; 247:118728. [PMID: 34923136 DOI: 10.1016/j.neuroimage.2021.118728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 11/28/2022] Open
Abstract
Resting-state functional MRI (rsfMRI) provides a view of human brain organization based on correlation patterns of blood oxygen level dependent (BOLD) signals recorded across the whole brain. The neural basis of resting-state BOLD fluctuations and their correlation remains poorly understood. We simultaneously recorded oxygen level, spikes, and local field potential (LFP) at multiple sites in awake, resting monkeys. Following a spike, the average local oxygen and LFP voltage responses each resemble a task-driven BOLD response, with LFP preceding oxygen by 0.5 s. Between sites, features of the long-range correlation patterns of oxygen, LFP, and spikes are similar to features seen in rsfMRI. Most of the variance shared between sites lies in the infraslow frequency band (0.01-0.1 Hz) and in the infraslow envelope of higher-frequency bands (e.g. gamma LFP). While gamma LFP and infraslow LFP are both strong correlates of local oxygen, infraslow LFP explains significantly more of the variance shared between correlated oxygen signals than any other electrophysiological signal. Together these findings are consistent with a causal relationship between infraslow LFP and long-range oxygen correlations in the resting state.
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Affiliation(s)
- Jingfeng M Li
- Department of Neuroscience, Washington University School of Medicine, 660 S Euclid Ave, Box 8108, St Louis, MO 63110, USA
| | - Benjamin T Acland
- Department of Neuroscience, Washington University School of Medicine, 660 S Euclid Ave, Box 8108, St Louis, MO 63110, USA
| | - Alexander S Brenner
- Department of Biomedical Engineering, Washington University, St Louis, MO 63130, USA
| | - William J Bentley
- Department of Neuroscience, Washington University School of Medicine, 660 S Euclid Ave, Box 8108, St Louis, MO 63110, USA
| | - Lawrence H Snyder
- Department of Neuroscience, Washington University School of Medicine, 660 S Euclid Ave, Box 8108, St Louis, MO 63110, USA; Department of Biomedical Engineering, Washington University, St Louis, MO 63130, USA.
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10
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Bijsterbosch JD, Valk SL, Wang D, Glasser MF. Recent developments in representations of the connectome. Neuroimage 2021; 243:118533. [PMID: 34469814 PMCID: PMC8842504 DOI: 10.1016/j.neuroimage.2021.118533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 07/16/2021] [Accepted: 08/28/2021] [Indexed: 02/03/2023] Open
Abstract
Research into the human connectome (i.e., all connections in the human brain) with the use of resting state functional MRI has rapidly increased in popularity in recent years, especially with the growing availability of large-scale neuroimaging datasets. The goal of this review article is to describe innovations in functional connectome representations that have come about in the past 8 years, since the 2013 NeuroImage special issue on 'Mapping the Connectome'. In the period, research has shifted from group-level brain parcellations towards the characterization of the individualized connectome and of relationships between individual connectomic differences and behavioral/clinical variation. Achieving subject-specific accuracy in parcel boundaries while retaining cross-subject correspondence is challenging, and a variety of different approaches are being developed to meet this challenge, including improved alignment, improved noise reduction, and robust group-to-subject mapping approaches. Beyond the interest in the individualized connectome, new representations of the data are being studied to complement the traditional parcellated connectome representation (i.e., pairwise connections between distinct brain regions), such as methods that capture overlapping and smoothly varying patterns of connectivity ('gradients'). These different connectome representations offer complimentary insights into the inherent functional organization of the brain, but challenges for functional connectome research remain. Interpretability will be improved by future research towards gaining insights into the neural mechanisms underlying connectome observations obtained from functional MRI. Validation studies comparing different connectome representations are also needed to build consensus and confidence to proceed with clinical trials that may produce meaningful clinical translation of connectome insights.
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Affiliation(s)
- Janine D Bijsterbosch
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA.
| | - Sofie L Valk
- Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; INM-7, Forschungszentrum Jülich, Jülich, Germany
| | - Danhong Wang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA
| | - Matthew F Glasser
- Department of Radiology, Washington University School of Medicine, Saint Louis, MO, 63110, USA; Department of Neuroscience, Washington University School of Medicine, Saint Louis, Missouri, 63110, USA
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11
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Contribution of animal models toward understanding resting state functional connectivity. Neuroimage 2021; 245:118630. [PMID: 34644593 DOI: 10.1016/j.neuroimage.2021.118630] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 08/06/2021] [Accepted: 09/29/2021] [Indexed: 12/27/2022] Open
Abstract
Functional connectivity, which reflects the spatial and temporal organization of intrinsic activity throughout the brain, is one of the most studied measures in human neuroimaging research. The noninvasive acquisition of resting state functional magnetic resonance imaging (rs-fMRI) allows the characterization of features designated as functional networks, functional connectivity gradients, and time-varying activity patterns that provide insight into the intrinsic functional organization of the brain and potential alterations related to brain dysfunction. Functional connectivity, hence, captures dimensions of the brain's activity that have enormous potential for both clinical and preclinical research. However, the mechanisms underlying functional connectivity have yet to be fully characterized, hindering interpretation of rs-fMRI studies. As in other branches of neuroscience, the identification of the neurophysiological processes that contribute to functional connectivity largely depends on research conducted on laboratory animals, which provide a platform where specific, multi-dimensional investigations that involve invasive measurements can be carried out. These highly controlled experiments facilitate the interpretation of the temporal correlations observed across the brain. Indeed, information obtained from animal experimentation to date is the basis for our current understanding of the underlying basis for functional brain connectivity. This review presents a compendium of some of the most critical advances in the field based on the efforts made by the animal neuroimaging community.
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12
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Zhang Q, Gheres KW, Drew PJ. Origins of 1/f-like tissue oxygenation fluctuations in the murine cortex. PLoS Biol 2021; 19:e3001298. [PMID: 34264930 PMCID: PMC8282088 DOI: 10.1371/journal.pbio.3001298] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 05/24/2021] [Indexed: 01/07/2023] Open
Abstract
The concentration of oxygen in the brain spontaneously fluctuates, and the distribution of power in these fluctuations has a 1/f-like spectra, where the power present at low frequencies of the power spectrum is orders of magnitude higher than at higher frequencies. Though these oscillations have been interpreted as being driven by neural activity, the origin of these 1/f-like oscillations is not well understood. Here, to gain insight of the origin of the 1/f-like oxygen fluctuations, we investigated the dynamics of tissue oxygenation and neural activity in awake behaving mice. We found that oxygen signal recorded from the cortex of mice had 1/f-like spectra. However, band-limited power in the local field potential did not show corresponding 1/f-like fluctuations. When local neural activity was suppressed, the 1/f-like fluctuations in oxygen concentration persisted. Two-photon measurements of erythrocyte spacing fluctuations and mathematical modeling show that stochastic fluctuations in erythrocyte flow could underlie 1/f-like dynamics in oxygenation. These results suggest that the discrete nature of erythrocytes and their irregular flow, rather than fluctuations in neural activity, could drive 1/f-like fluctuations in tissue oxygenation.
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Affiliation(s)
- Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
| | - Kyle W. Gheres
- Graduate Program in Molecular Cellular and Integrative Biosciences, The Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Patrick J. Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Neurosurgery, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail: (QZ); (PJD)
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13
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Dissociations between glucose metabolism and blood oxygenation in the human default mode network revealed by simultaneous PET-fMRI. Proc Natl Acad Sci U S A 2021; 118:2021913118. [PMID: 34193521 PMCID: PMC8271663 DOI: 10.1073/pnas.2021913118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A consistent finding from functional MRI (fMRI) of externally focused cognitive control is negative signal change in the brain’s default mode network (DMN), but it is unknown whether this reflects an increase of synaptic activity during rest periods or active suppression during task. Using hybrid PET-MRI, we show that task-positive fMRI responses align with increasing glucose metabolism during cognitive control, but task-negative fMRI responses in DMN are not accompanied by corresponding decreases in metabolism. The results are incompatible with an interpretation of task-negative fMRI signal in DMN as a relative metabolic increase during a resting baseline condition. The present results open up avenues for understanding abnormal fMRI activity patterns in DMN in aging and psychiatric disease. The finding of reduced functional MRI (fMRI) activity in the default mode network (DMN) during externally focused cognitive control has been highly influential to our understanding of human brain function. However, these negative fMRI responses, measured as relative decreases in the blood-oxygenation-level–dependent (BOLD) response between rest and task, have also prompted major questions of interpretation. Using hybrid functional positron emission tomography (PET)-MRI, this study shows that task-positive and -negative BOLD responses do not reflect antagonistic patterns of synaptic metabolism. Task-positive BOLD responses in attention and control networks were accompanied by concomitant increases in glucose metabolism during cognitive control, but metabolism in widespread DMN remained high during rest and task despite negative BOLD responses. Dissociations between glucose metabolism and the BOLD response specific to the DMN reveal functional heterogeneity in this network and demonstrate that negative BOLD responses during cognitive control should not be interpreted to reflect relative increases in metabolic activity during rest. Rather, neurovascular coupling underlying BOLD response patterns during rest and task in DMN appears fundamentally different from BOLD responses in other association networks during cognitive control.
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14
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Das A, Murphy K, Drew PJ. Rude mechanicals in brain haemodynamics: non-neural actors that influence blood flow. Philos Trans R Soc Lond B Biol Sci 2020; 376:20190635. [PMID: 33190603 DOI: 10.1098/rstb.2019.0635] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Fluctuations in blood oxygenation and flow are widely used to infer brain activity during resting-state functional magnetic resonance imaging (fMRI). However, there are strong systemic and vascular contributions to resting-state signals that are unrelated to ongoing neural activity. Importantly, these non-neural contributions to haemodynamic signals (or 'rude mechanicals') can be as large as or larger than the neurally evoked components. Here, we review the two broad classes of drivers of these signals. One is systemic and is tied to fluctuations in external drivers such as heart rate and breathing, and the robust autoregulatory mechanisms that try to maintain a constant milieu in the brain. The other class comprises local, active fluctuations that appear to be intrinsic to vascular tissue and are likely similar to active local fluctuations seen in vasculature all over the body. In this review, we describe these non-neural fluctuations and some of the tools developed to correct for them when interpreting fMRI recordings. However, we also emphasize the links between these vascular fluctuations and brain physiology and point to ways in which fMRI measurements can be used to exploit such links to gain valuable information about neurovascular health and about internal brain states. This article is part of the theme issue 'Key relationships between non-invasive functional neuroimaging and the underlying neuronal activity'.
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Affiliation(s)
- Aniruddha Das
- Department of Neuroscience, Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Kevin Murphy
- Cardiff University Brain Research Imaging Centre (CUBRIC), School of Physics and Astronomy, Cardiff University, Cardiff CF24 4HQ, UK
| | - Patrick J Drew
- Departments of Engineering Science and Mechanics, Neurosurgery, and Biomedical Engineering, The Pennsylvania State University, University Park, PA 16802, USA
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15
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Bijsterbosch J, Harrison SJ, Jbabdi S, Woolrich M, Beckmann C, Smith S, Duff EP. Challenges and future directions for representations of functional brain organization. Nat Neurosci 2020; 23:1484-1495. [PMID: 33106677 DOI: 10.1038/s41593-020-00726-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/16/2020] [Indexed: 12/12/2022]
Abstract
A key principle of brain organization is the functional integration of brain regions into interconnected networks. Functional MRI scans acquired at rest offer insights into functional integration via patterns of coherent fluctuations in spontaneous activity, known as functional connectivity. These patterns have been studied intensively and have been linked to cognition and disease. However, the field is fractionated. Diverging analysis approaches have segregated the community into research silos, limiting the replication and clinical translation of findings. A primary source of this fractionation is the diversity of approaches used to reduce complex brain data into a lower-dimensional set of features for analysis and interpretation, which we refer to as brain representations. In this Primer, we provide an overview of different brain representations, lay out the challenges that have led to the fractionation of the field and that continue to form obstacles for convergence, and propose concrete guidelines to unite the field.
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Affiliation(s)
- Janine Bijsterbosch
- Mallinckrodt Institute of Radiology, Washington University in St Louis, Saint Louis, MO, USA. .,Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford. John Radcliffe Hospital, Oxford, UK.
| | - Samuel J Harrison
- Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford. John Radcliffe Hospital, Oxford, UK.,Translational Neuromodeling Unit, University of Zurich & ETH Zurich, Zurich, Switzerland
| | - Saad Jbabdi
- Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford. John Radcliffe Hospital, Oxford, UK
| | - Mark Woolrich
- Oxford Centre for Human Brain Activity (OHBA), Wellcome Centre for Integrative Neuroimaging, Department of Psychiatry, University of Oxford, Warneford Hospital, Oxford, UK
| | - Christian Beckmann
- Donders Institute and Department of Cognitive Neurosciences, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Stephen Smith
- Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford. John Radcliffe Hospital, Oxford, UK
| | - Eugene P Duff
- Centre for Functional MRI of the Brain (FMRIB), Wellcome Centre for Integrative Neuroimaging, Nuffield Department of Clinical Neurosciences, University of Oxford. John Radcliffe Hospital, Oxford, UK. .,Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Oxford, UK.
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16
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Krishna V, Young NA, Sammartino F. Imaging: Patient Selection, Targeting, and Outcome Biomarkers. Stereotact Funct Neurosurg 2020. [DOI: 10.1007/978-3-030-34906-6_36] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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17
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Zhang Q, Roche M, Gheres KW, Chaigneau E, Kedarasetti RT, Haselden WD, Charpak S, Drew PJ. Cerebral oxygenation during locomotion is modulated by respiration. Nat Commun 2019; 10:5515. [PMID: 31797933 PMCID: PMC6893036 DOI: 10.1038/s41467-019-13523-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 11/12/2019] [Indexed: 12/17/2022] Open
Abstract
In the brain, increased neural activity is correlated with increases of cerebral blood flow and tissue oxygenation. However, how cerebral oxygen dynamics are controlled in the behaving animal remains unclear. We investigated to what extent cerebral oxygenation varies during locomotion. We measured oxygen levels in the cortex of awake, head-fixed mice during locomotion using polarography, spectroscopy, and two-photon phosphorescence lifetime measurements of oxygen sensors. We find that locomotion significantly and globally increases cerebral oxygenation, specifically in areas involved in locomotion, as well as in the frontal cortex and the olfactory bulb. The oxygenation increase persists when neural activity and functional hyperemia are blocked, occurred both in the tissue and in arteries feeding the brain, and is tightly correlated with respiration rate and the phase of respiration cycle. Thus, breathing rate is a key modulator of cerebral oxygenation and should be monitored during hemodynamic imaging, such as in BOLD fMRI.
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Affiliation(s)
- Qingguang Zhang
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Morgane Roche
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Kyle W Gheres
- Graduate Program in Molecular Cellular and Integrative Biosciences, The Pennsylvania State University, University Park, PA, USA
| | - Emmanuelle Chaigneau
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Ravi T Kedarasetti
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - William D Haselden
- Medical Scientist Training Program and Neuroscience Graduate Program, The Pennsylvania State University, University Park, PA, USA
| | - Serge Charpak
- Institut National de la Santé et de la Recherche Médicale, U1128, Paris, France.,Laboratory of Neurophysiology and New Microscopies, Université Paris Descartes, Paris, France
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA. .,Department of Neurosurgery and Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
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18
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BOLD signal physiology: Models and applications. Neuroimage 2019; 187:116-127. [DOI: 10.1016/j.neuroimage.2018.03.018] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 02/14/2018] [Accepted: 03/08/2018] [Indexed: 12/14/2022] Open
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19
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Oya H, Gander PE, Petkov CI, Adolphs R, Nourski KV, Kawasaki H, Howard MA, Griffiths TD. Neural phase locking predicts BOLD response in human auditory cortex. Neuroimage 2018; 169:286-301. [PMID: 29274745 PMCID: PMC6139034 DOI: 10.1016/j.neuroimage.2017.12.051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/22/2017] [Accepted: 12/16/2017] [Indexed: 11/16/2022] Open
Abstract
Natural environments elicit both phase-locked and non-phase-locked neural responses to the stimulus in the brain. The interpretation of the BOLD signal to date has been based on an association of the non-phase-locked power of high-frequency local field potentials (LFPs), or the related spiking activity in single neurons or groups of neurons. Previous studies have not examined the prediction of the BOLD signal by phase-locked responses. We examined the relationship between the BOLD response and LFPs in the same nine human subjects from multiple corresponding points in the auditory cortex, using amplitude modulated pure tone stimuli of a duration to allow an analysis of phase locking of the sustained time period without contamination from the onset response. The results demonstrate that both phase locking at the modulation frequency and its harmonics, and the oscillatory power in gamma/high-gamma bands are required to predict the BOLD response. Biophysical models of BOLD signal generation in auditory cortex therefore require revision and the incorporation of both phase locking to rhythmic sensory stimuli and power changes in the ensemble neural activity.
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Affiliation(s)
- Hiroyuki Oya
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA.
| | - Phillip E Gander
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA
| | | | - Ralph Adolphs
- Division of the Humanities and Social Sciences, California Institute of Technology, Pasadena, CA 91125, USA
| | - Kirill V Nourski
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA
| | - Hiroto Kawasaki
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA
| | - Matthew A Howard
- Department of Neurosurgery, Human Brain Research Laboratory, University of Iowa, Iowa City, IA 52252, USA
| | - Timothy D Griffiths
- Wellcome Trust Centre for Neuroimaging, Institute of Neurology, University College London, UK
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20
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Moayedi M, Salomons TV, Atlas LY. Pain Neuroimaging in Humans: A Primer for Beginners and Non-Imagers. THE JOURNAL OF PAIN 2018; 19:961.e1-961.e21. [PMID: 29608974 PMCID: PMC6192705 DOI: 10.1016/j.jpain.2018.03.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 02/22/2018] [Accepted: 03/19/2018] [Indexed: 01/06/2023]
Abstract
Human pain neuroimaging has exploded in the past 2 decades. During this time, the broader neuroimaging community has continued to investigate and refine methods. Another key to progress is exchange with clinicians and pain scientists working with other model systems and approaches. These collaborative efforts require that non-imagers be able to evaluate and assess the evidence provided in these reports. Likewise, new trainees must design rigorous and reliable pain imaging experiments. In this article we provide a guideline for designing, reading, evaluating, analyzing, and reporting results of a pain neuroimaging experiment, with a focus on functional and structural magnetic resonance imaging. We focus in particular on considerations that are unique to neuroimaging studies of pain in humans, including study design and analysis, inferences that can be drawn from these studies, and the strengths and limitations of the approach.
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Affiliation(s)
- Massieh Moayedi
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada; University of Toronto Centre for the Study of Pain, University of Toronto, Toronto, Ontario, Canada; Department of Dentistry, Mount Sinai Hospital, Toronto, Ontario, Canada.
| | - Tim V Salomons
- School of Psychology and Clinical Language Science, University of Reading, Reading, UK; Centre for Integrated Neuroscience and Neurodynamics, University of Reading, Reading, UK
| | - Lauren Y Atlas
- National Center for Complementary and Integrative Health, National Institutes of Health, Bethesda, Maryland; National Institute on Drug Abuse, National Institutes of Health, Bethesda, Maryland
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21
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Abstract
The majority of meditation involves focusing attention on internal events or sensations and becoming aware of emotions. The insula cortex, through a functional connection with the prefrontal cortex and other brain regions, plays a key role in integrating external sensory information with internal bodily state signals and emotional awareness. The purpose of this exploratory study was to examine the resting-state functional connectivity of the insula with other brain regions in meditation practitioners and control subjects. Thirty-five Brain Wave Vibration meditation practitioners and 33 controls without meditation experience were included in this study. All subjects underwent 4.68-min resting-state functional scanning runs using magnetic resonance imaging. The anterior and posterior insulae were chosen as seed regions for the functional connectivity map. Meditation practitioners showed significantly greater insula-related functional connectivity in the thalamus, caudate, middle frontal gyrus, and superior temporal gyrus than did controls. Control subjects demonstrated greater functional connectivity with the posterior insula in the parahippocampal gyrus. Our findings suggest that the practice of Brain Wave Vibration meditation may be associated with functional differences in regions related to focused attention, executive control, and emotional awareness and regulation.
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22
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Abstract
The default mode network (DMN) is a collection of cortical brain regions that is active during states of rest or quiet wakefulness in humans and other mammalian species. A pertinent characteristic of the DMN is a suppression of local field potential gamma activity during cognitive task performance as well as during engagement with external sensory stimuli. Conversely, gamma activity is elevated in the DMN during rest. Here, we document that the rat basal forebrain (BF) exhibits the same pattern of responses, namely pronounced gamma oscillations during quiet wakefulness in the home cage and suppression of this activity during active exploration of an unfamiliar environment. We show that gamma oscillations are localized to the BF and that gamma-band activity in the BF has a directional influence on a hub of the rat DMN, the anterior cingulate cortex, during DMN-dominated brain states. The BF is well known as an ascending, activating, neuromodulatory system involved in wake-sleep regulation, memory formation, and regulation of sensory information processing. Our findings suggest a hitherto undocumented role of the BF as a subcortical node of the DMN, which we speculate may be important for switching between internally and externally directed brain states. We discuss potential BF projection circuits that could underlie its role in DMN regulation and highlight that certain BF nuclei may provide potential target regions for up- or down-regulation of DMN activity that might prove useful for treatment of DMN dysfunction in conditions such as epilepsy or major depressive disorder.
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23
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Mash LE, Reiter MA, Linke AC, Townsend J, Müller RA. Multimodal approaches to functional connectivity in autism spectrum disorders: An integrative perspective. Dev Neurobiol 2017; 78:456-473. [PMID: 29266810 DOI: 10.1002/dneu.22570] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Revised: 12/18/2017] [Accepted: 12/18/2017] [Indexed: 12/22/2022]
Abstract
Atypical functional connectivity has been implicated in autism spectrum disorders (ASDs). However, the literature to date has been largely inconsistent, with mixed and conflicting reports of hypo- and hyper-connectivity. These discrepancies are partly due to differences between various neuroimaging modalities. Functional magnetic resonance imaging (fMRI), electroencephalography (EEG), and magnetoencephalography (MEG) measure distinct indices of functional connectivity (e.g., blood-oxygenation level-dependent [BOLD] signal vs. electrical activity). Furthermore, each method has unique benefits and disadvantages with respect to spatial and temporal resolution, vulnerability to specific artifacts, and practical implementation. Thus far, functional connectivity research on ASDs has remained almost exclusively unimodal; therefore, interpreting findings across modalities remains a challenge. Multimodal integration of fMRI, EEG, and MEG data is critical in resolving discrepancies in the literature, and working toward a unifying framework for interpreting past and future findings. This review aims to provide a theoretical foundation for future multimodal research on ASDs. First, we will discuss the merits and shortcomings of several popular theories in ASD functional connectivity research, using examples from the literature to date. Next, the neurophysiological relationships between imaging modalities, including their relationship with invasive neural recordings, will be reviewed. Finally, methodological approaches to multimodal data integration will be presented, and their future application to ASDs will be discussed. Analyses relating transient patterns of neural activity ("states") are particularly promising. This strategy provides a comparable measure across modalities, captures complex spatiotemporal patterns, and is a natural extension of recent dynamic fMRI research in ASDs. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 456-473, 2018.
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Affiliation(s)
- Lisa E Mash
- San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California.,Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Maya A Reiter
- San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, California.,Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Annika C Linke
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
| | - Jeanne Townsend
- Department of Neurosciences, University of California, San Diego, San Diego, California
| | - Ralph-Axel Müller
- Brain Development Imaging Laboratories, Department of Psychology, San Diego State University, San Diego, California
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24
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Wright PW, Brier LM, Bauer AQ, Baxter GA, Kraft AW, Reisman MD, Bice AR, Snyder AZ, Lee JM, Culver JP. Functional connectivity structure of cortical calcium dynamics in anesthetized and awake mice. PLoS One 2017; 12:e0185759. [PMID: 29049297 PMCID: PMC5648115 DOI: 10.1371/journal.pone.0185759] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 09/19/2017] [Indexed: 11/30/2022] Open
Abstract
The interplay between hemodynamic-based markers of cortical activity (e.g. fMRI and optical intrinsic signal imaging), which are an indirect and relatively slow report of neural activity, and underlying synaptic electrical and metabolic activity through neurovascular coupling is a topic of ongoing research and debate. As application of resting state functional connectivity measures is extended further into topics such as brain development, aging and disease, the importance of understanding the fundamental physiological basis for functional connectivity will grow. Here we extend functional connectivity analysis from hemodynamic- to calcium-based imaging. Transgenic mice (n = 7) expressing a fluorescent calcium indicator (GCaMP6) driven by the Thy1 promoter in glutamatergic neurons were imaged transcranially in both anesthetized (using ketamine/xylazine) and awake states. Sequential LED illumination (λ = 454, 523, 595, 640nm) enabled concurrent imaging of both GCaMP6 fluorescence emission (corrected for hemoglobin absorption) and hemodynamics. Functional connectivity network maps were constructed for infraslow (0.009–0.08Hz), intermediate (0.08–0.4Hz), and high (0.4–4.0Hz) frequency bands. At infraslow and intermediate frequencies, commonly used in BOLD fMRI and fcOIS studies of functional connectivity and implicated in neurovascular coupling mechanisms, GCaMP6 and HbO2 functional connectivity structures were in high agreement, both qualitatively and also quantitatively through a measure of spatial similarity. The spontaneous dynamics of both contrasts had the highest correlation when the GCaMP6 signal was delayed with a ~0.6–1.5s temporal offset. Within the higher-frequency delta band, sensitive to slow wave sleep oscillations in non-REM sleep and anesthesia, we evaluate the speed with which the connectivity analysis stabilized and found that the functional connectivity maps captured putative network structure within time window lengths as short as 30 seconds. Homotopic GCaMP6 functional connectivity maps at 0.4–4.0Hz in the anesthetized states show a striking correlated and anti-correlated structure along the anterior to posterior axis. This structure is potentially explained in part by observed propagation of delta-band activity from frontal somatomotor regions to visuoparietal areas. During awake imaging, this spatio-temporal quality is altered, and a more complex and detailed functional connectivity structure is observed. The combined calcium/hemoglobin imaging technique described here will enable the dissociation of changes in ionic and hemodynamic functional structure and neurovascular coupling and provide a framework for subsequent studies of neurological disease such as stroke.
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Affiliation(s)
- Patrick W. Wright
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lindsey M. Brier
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Adam Q. Bauer
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Grant A. Baxter
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andrew W. Kraft
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Matthew D. Reisman
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Physics, Washington University in St. Louis, St. Louis, Missouri, United States of America
| | - Annie R. Bice
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Abraham Z. Snyder
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Jin-Moo Lee
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department Neurology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Joseph P. Culver
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Neuroscience, Washington University in St. Louis, St. Louis, Missouri, United States of America
- * E-mail:
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25
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Sten S, Lundengård K, Witt S, Cedersund G, Elinder F, Engström M. Neural inhibition can explain negative BOLD responses: A mechanistic modelling and fMRI study. Neuroimage 2017; 158:219-231. [DOI: 10.1016/j.neuroimage.2017.07.002] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/03/2017] [Accepted: 07/02/2017] [Indexed: 12/13/2022] Open
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26
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Kim JH, Choi SH, Jang JH, Lee DH, Lee KJ, Lee WJ, Moon JY, Kim YC, Kang DH. Impaired insula functional connectivity associated with persistent pain perception in patients with complex regional pain syndrome. PLoS One 2017; 12:e0180479. [PMID: 28692702 PMCID: PMC5503260 DOI: 10.1371/journal.pone.0180479] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 06/15/2017] [Indexed: 11/18/2022] Open
Abstract
Given that the insula plays a contributory role in the perception of chronic pain, we examined the resting-state functional connectivity between the insular cortex and other brain regions to investigate neural underpinnings of persisting perception of background pain in patients with complex regional pain syndrome (CRPS). A total of 25 patients with CRPS and 25 matched healthy controls underwent functional magnetic resonance imaging at rest. With the anterior and posterior insular cortices as seed regions, we compared the strength of the resting-state functional connectivity between the two groups. Functional connectivity between the anterior and posterior insular cortices and the postcentral and inferior frontal gyri, cingulate cortices was reduced in patients with CRPS compared with controls. Additionally, greater reductions in functional connectivity between the anterior insula and right postcentral gyrus were associated with more severe sensory pain in patients with CRPS (short-form McGill Pain Questionnaire sensory subscores, r = -.517, P = .023). The present results imply a possible role of the insula in aberrant processing of pain information in patients with CRPS. The findings suggest that a functional derangement of the connection between one of the somatosensory cortical functions of perception and one of the insular functions of awareness can play a significant role in the persistent experience of regional pain that is not confined to a specific nerve territory.
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Affiliation(s)
- Jae-Hun Kim
- Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Soo-Hee Choi
- Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Psychiatry and Institute of Human Behavioral Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Joon Hwan Jang
- Department of Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Do-Hyeong Lee
- Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Kyung-Jun Lee
- Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Won Joon Lee
- Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea
| | - Jee Youn Moon
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Yong Chul Kim
- Department of Anesthesiology and Pain Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Do-Hyung Kang
- Department of Psychiatry, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Psychiatry and Institute of Human Behavioral Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- * E-mail:
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27
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Abstract
Molecular oxygen (O2) is essential to brain function and mechanisms necessary to regulate variations in delivery or utilization of O2 are crucial to support normal brain homeostasis, physiology and energy metabolism. Any imbalance in cerebral tissue partial pressure of O2 (pO2) levels may lead to pathophysiological complications including increased reactive O2 species generation leading to oxidative stress when tissue O2 level is too high or too low. Accordingly, the need for oximetry methods, which assess cerebral pO2in vivo and in real time, is imperative to understand the role of O2 in various metabolic and disease states, including the effects of treatment and therapy options. In this review, we provide a brief overview of the common in vivo oximetry methodologies for measuring cerebral pO2. We discuss the advantages and limitations of oximetry methodologies to measure cerebral pO2in vivo followed by a more in-depth review of electron paramagnetic resonance oximetry spectroscopy and imaging using several examples of current electron paramagnetic resonance oximetry applications in the brain.
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Affiliation(s)
- John M Weaver
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ke Jian Liu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Center of Biomedical Research Excellence, College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.,Department of Neurology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
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28
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Palop JJ, Mucke L. Network abnormalities and interneuron dysfunction in Alzheimer disease. Nat Rev Neurosci 2016; 17:777-792. [PMID: 27829687 DOI: 10.1038/nrn.2016.141] [Citation(s) in RCA: 594] [Impact Index Per Article: 74.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The function of neural circuits and networks can be controlled, in part, by modulating the synchrony of their components' activities. Network hypersynchrony and altered oscillatory rhythmic activity may contribute to cognitive abnormalities in Alzheimer disease (AD). In this condition, network activities that support cognition are altered decades before clinical disease onset, and these alterations predict future pathology and brain atrophy. Although the precise causes and pathophysiological consequences of these network alterations remain to be defined, interneuron dysfunction and network abnormalities have emerged as potential mechanisms of cognitive dysfunction in AD and related disorders. Here, we explore the concept that modulating these mechanisms may help to improve brain function in these conditions.
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Affiliation(s)
- Jorge J Palop
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
| | - Lennart Mucke
- Gladstone Institute of Neurological Disease, 1650 Owens Street, San Francisco, California 94158, USA.,Department of Neurology, University of California, San Francisco, 1650 Owens Street, San Francisco, California 94158, USA
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29
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Konishi M, McLaren DG, Engen H, Smallwood J. Shaped by the Past: The Default Mode Network Supports Cognition that Is Independent of Immediate Perceptual Input. PLoS One 2015; 10:e0132209. [PMID: 26125559 PMCID: PMC4488375 DOI: 10.1371/journal.pone.0132209] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 06/12/2015] [Indexed: 12/15/2022] Open
Abstract
Although many different accounts of the functions of the default mode network (DMN) have been proposed, few can adequately account for the spectrum of different cognitive functions that utilize this network. The current study used functional magnetic resonance imaging (fMRI) to explore the hypothesis that the role of the DMN in higher order cognition is to allow cognition to be shaped by information from stored representations rather than information in the immediate environment. Using a novel task paradigm, we observed increased BOLD activity in regions of the medial prefrontal cortex and posterior cingulate cortex when individuals made decisions on the location of shapes from the prior trial and decreased BOLD activity when individuals made decisions on the location of shapes on the current trial. These data are inconsistent with views of the DMN as a task-negative system or one that is sensitive only to stimuli with strong personal or emotional ties. Instead the involvement of the DMN when people make decisions about where a shape was, rather than where it is now, supports the hypothesis that the core hubs of the DMN allow cognition to be guided by information other than the immediate perceptual input. We propose that a variety of different forms of higher order thought (such as imagining the future or considering the perspective of another person) engage the DMN because these more complex introspective forms of higher order thought all depend on the capacity for cognition to be shaped by representations that are not present in the external environment.
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Affiliation(s)
- Mahiko Konishi
- Department of Psychology & York Neuroimaging Centre, University of York, York, United Kingdom
| | - Donald George McLaren
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, United States of America
| | - Haakon Engen
- Department of Social Neuroscience, Max Plank Institute for Human Cognitive Brain Sciences, Leipzig, Germany
| | - Jonathan Smallwood
- Department of Psychology & York Neuroimaging Centre, University of York, York, United Kingdom
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Abstract
The mechanism underlying temporal correlations among blood oxygen level-dependent signals is unclear. We used oxygen polarography to better characterize oxygen fluctuations and their correlation and to gain insight into the driving mechanism. The power spectrum of local oxygen fluctuations is inversely proportional to frequency raised to a power (1/f) raised to the beta, with an additional positive band-limited component centered at 0.06 Hz. In contrast, the power of the correlated oxygen signal is band limited from ∼ 0.01 Hz to 0.4 Hz with a peak at 0.06 Hz. These results suggest that there is a band-limited mechanism (or mechanisms) driving interregional oxygen correlation that is distinct from the mechanism(s) driving local (1/f) oxygen fluctuations. Candidates for driving interregional oxygen correlation include rhythmic or pseudo-oscillatory mechanisms.
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