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Whitaker AA, Waghmare S, Montgomery RN, Aaron SE, Eickmeyer SM, Vidoni ED, Billinger SA. Lower middle cerebral artery blood velocity during low-volume high-intensity interval exercise in chronic stroke. J Cereb Blood Flow Metab 2024; 44:627-640. [PMID: 37708242 DOI: 10.1177/0271678x231201472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
High-intensity interval training (HIIE) may present unique challenges to the cerebrovascular system in individuals post-stroke. We hypothesized lower middle cerebral artery blood velocity (MCAv) in individuals post-stroke: 1) during 10 minutes of HIIE, 2) immediately following HIIE, and 3) 30 minutes after HIIE, compared to age- and sex-matched controls (CON). We used a recumbent stepper submaximal exercise test to determine workloads for high-intensity and active recovery. Our low volume HIIE protocol consisted of 1-minute intervals for 10 minutes. During HIIE, we measured MCAv, mean arterial pressure (MAP), heart rate (HR), and end tidal carbon dioxide (PETCO2). We assessed carotid-femoral pulse wave velocity as a measure of arterial stiffness. Fifty participants completed the study (25 post-stroke, 76% ischemic, 32% moderate disability). Individuals post-stroke had lower MCAv during HIIE compared to CON (p = 0.03), which remained 30 minutes after HIIE. Individuals post-stroke had greater arterial stiffness (p = 0.01) which was moderately associated with a smaller MCAv responsiveness during HIIE (r = -0.44). No differences were found for MAP, HR, and PETCO2. This study suggests individuals post-stroke had a lower MCAv during HIIE compared to their peers, which remained during recovery up to 30 minutes. Arterial stiffness may contribute to the lower cerebrovascular responsiveness post-stroke.
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Affiliation(s)
- Alicen A Whitaker
- Department of Physical Therapy, Rehabilitation Science, and Athletic Training, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin, Milwaukee, WI, USA
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Saniya Waghmare
- Department of Physical Therapy, Rehabilitation Science, and Athletic Training, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Robert N Montgomery
- Department of Biostatistics & Data Science, University of Kansas Medical Center, Kansas City, KS, USA
| | - Stacey E Aaron
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Sarah M Eickmeyer
- Department of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
| | - Eric D Vidoni
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
- University of Kansas Alzheimer's Disease Research Center, Fairway, KS, USA
| | - Sandra A Billinger
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS, USA
- Department of Physical Medicine and Rehabilitation, University of Kansas Medical Center, Kansas City, KS, USA
- University of Kansas Alzheimer's Disease Research Center, Fairway, KS, USA
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS, USA
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Chen S, Chen H, Duan J, Cui L, Liu R, Xing Y. Impaired Dynamic Cerebral Autoregulation in Patients With Cerebral Venous Sinus Thrombosis: Evaluation Using Transcranial Doppler and Silent Reading Stimulation. Ultrasound Med Biol 2023; 49:2221-2226. [PMID: 37532632 DOI: 10.1016/j.ultrasmedbio.2023.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 06/21/2023] [Accepted: 07/11/2023] [Indexed: 08/04/2023]
Abstract
OBJECTIVE Cerebral venous sinus thrombosis (CVST) may impair dynamic cerebral autoregulation (dCA) of the middle cerebral artery (MCA). However, most studies have focused on dCA of the MCA; a few studies are based on the posterior cerebral artery (PCA) during silent reading and neurovascular coupling (NVC). This study explored the effects of CVST on dCA of the MCA and PCA during silent reading and NVC. METHODS From January 2021 to August 2022, 60 CVST patients and 30 controls were enrolled in this study. Non-invasive continuous beat-to-beat blood pressure, cerebral blood flow velocity and other associated information on the MCA and PCA during silent reading were collected using a transcranial Doppler. NVC assessment was performed by opening and closing the eyes periodically based on voice prompts, and eye-opening visual stimulation was achieved by silently reading Chinese tourism materials. Visual stimulation signals can selectively activate Brodmann's areas 17, 18, and 19 of the occipital when reading silently with open eyes, prompting them to release neurotransmitters and dilate PCA. dCA was determined by transfer function analysis. RESULTS In dCA of the PCA during silent reading, the CVST group's very low frequency phase was lower than that of the control group (p = 0.047). In NVC, the difference in the indexes of the cerebrovascular conductance and visually evoked flow response of the CVST group were lower than those of the control group (p = 0.017 and p = 0.019, respectively). CONCLUSION Compared with the control group, dCA and NVC of the PCA during silent reading were impaired in CVST patients.
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Affiliation(s)
- Songwei Chen
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Hongxiu Chen
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Jiangang Duan
- Department of Emergency, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Liuping Cui
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Ran Liu
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
| | - Yingqi Xing
- Department of Vascular Ultrasonography, Xuanwu Hospital, Capital Medical University, Beijing, China; Beijing Diagnostic Center of Vascular Ultrasound, Beijing, China; Center of Vascular Ultrasonography, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
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Abstract
Astrocyte endfeet enwrap the entire vascular tree within the central nervous system, where they perform important functions in regulating the blood-brain barrier (BBB), cerebral blood flow, nutrient uptake, and waste clearance. Accordingly, astrocyte endfeet contain specialized organelles and proteins, including local protein translation machinery and highly organized scaffold proteins, which anchor channels, transporters, receptors, and enzymes critical for astrocyte-vascular interactions. Many neurological diseases are characterized by the loss of polarization of specific endfoot proteins, vascular dysregulation, BBB disruption, altered waste clearance, or, in extreme cases, loss of endfoot coverage. A role for astrocyte endfeet has been demonstrated or postulated in many of these conditions. This review provides an overview of the development, composition, function, and pathological changes of astrocyte endfeet and highlights the gaps in our knowledge that future research should address.
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Affiliation(s)
- Blanca Díaz-Castro
- UK Dementia Research Institute and Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK;
| | - Stefanie Robel
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA;
| | - Anusha Mishra
- Department of Neurology Jungers Center for Neurosciences Research and Knight Cardiovascular Institute, Oregon Health & Science University, Portland, Oregon, USA;
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Staehr C, Giblin JT, Gutiérrez‐Jiménez E, Guldbrandsen HØ, Tang J, Sandow SL, Boas DA, Matchkov VV. Neurovascular Uncoupling Is Linked to Microcirculatory Dysfunction in Regions Outside the Ischemic Core Following Ischemic Stroke. J Am Heart Assoc 2023; 12:e029527. [PMID: 37232244 PMCID: PMC10381981 DOI: 10.1161/jaha.123.029527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 04/19/2023] [Indexed: 05/27/2023]
Abstract
Background Normal brain function depends on the ability of the vasculature to increase blood flow to regions with high metabolic demands. Impaired neurovascular coupling, such as the local hyperemic response to neuronal activity, may contribute to poor neurological outcome after stroke despite successful recanalization, that is, futile recanalization. Methods and Results Mice implanted with chronic cranial windows were trained for awake head-fixation before experiments. One-hour occlusion of the anterior middle cerebral artery branch was induced using single-vessel photothrombosis. Cerebral perfusion and neurovascular coupling were assessed by optical coherence tomography and laser speckle contrast imaging. Capillaries and pericytes were studied in perfusion-fixed tissue by labeling lectin and platelet-derived growth factor receptor β. Arterial occlusion induced multiple spreading depolarizations over 1 hour associated with substantially reduced blood flow in the peri-ischemic cortex. Approximately half of the capillaries in the peri-ischemic area were no longer perfused at the 3- and 24-hour follow-up (45% [95% CI, 33%-58%] and 53% [95% CI, 39%-66%] reduction, respectively; P<0.0001), which was associated with contraction of an equivalent proportion of peri-ischemic capillary pericytes. The capillaries in the peri-ischemic cortex that remained perfused showed increased point prevalence of dynamic flow stalling (0.5% [95% CI, 0.2%-0.7%] at baseline, 5.1% [95% CI, 3.2%-6.5%] and 3.2% [95% CI, 1.1%-5.3%] at 3- and 24-hour follow-up, respectively; P=0.001). Whisker stimulation at the 3- and 24-hour follow-up led to reduced neurovascular coupling responses in the sensory cortex corresponding to the peri-ischemic region compared with that observed at baseline. Conclusions Arterial occlusion led to contraction of capillary pericytes and capillary flow stalling in the peri-ischemic cortex. Capillary dysfunction was associated with neurovascular uncoupling. Neurovascular coupling impairment associated with capillary dysfunction may be a mechanism that contributes to futile recanalization. Hence, the results from this study suggest a novel treatment target to improve neurological outcome after stroke.
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Affiliation(s)
- Christian Staehr
- Department of BiomedicineAarhus UniversityAarhusDenmark
- Neurophotonics Center, Department of Biomedical EngineeringBoston UniversityBostonMAUSA
| | - John T. Giblin
- Neurophotonics Center, Department of Biomedical EngineeringBoston UniversityBostonMAUSA
| | - Eugenio Gutiérrez‐Jiménez
- Center of Functionally Integrative Neuroscience, Institute for Clinical MedicineAarhus UniversityAarhusDenmark
| | | | - Jianbo Tang
- Neurophotonics Center, Department of Biomedical EngineeringBoston UniversityBostonMAUSA
- Department of Biomedical EngineeringSouthern University of Science and TechnologyShenzhenChina
| | - Shaun L. Sandow
- Biomedical Science, School of HealthUniversity of the Sunshine CoastSippy DownsAustralia
- Centre for Clinical Research, Faculty of MedicineThe University of QueenslandBrisbaneAustralia
| | - David A. Boas
- Neurophotonics Center, Department of Biomedical EngineeringBoston UniversityBostonMAUSA
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Lia A, Di Spiezio A, Speggiorin M, Zonta M. Two decades of astrocytes in neurovascular coupling. Front Netw Physiol 2023; 3:1162757. [PMID: 37078069 PMCID: PMC10106690 DOI: 10.3389/fnetp.2023.1162757] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 03/23/2023] [Indexed: 04/05/2023]
Abstract
The brain is a highly energy demanding organ, which accounts in humans for the 20% of total energy consumption at resting state although comprising only 2% of the body mass. The necessary delivery of nutrients to brain parenchyma is ensured by the cerebral circulatory system, through the exchange of glucose and oxygen (O2) at the capillary level. Notably, a tight spatial and temporal correlation exists between local increases in neuronal activity and the subsequent changes in regional cerebral blood flow. The recognized concept of neurovascular coupling (NVC), also named functional hyperemia, expresses this close relationship and stands at the basis of the modern functional brain imaging techniques. Different cellular and molecular mechanisms have been proposed to mediate this tight coupling. In this context, astrocytes are ideally positioned to act as relay elements that sense neuronal activity through their perisynaptic processes and release vasodilator agents at their endfeet in contact with brain parenchymal vessels. Two decades after the astrocyte involvement in neurovascular coupling has been proposed, we here review the experimental evidence that contributed to unraveling the molecular and cellular mechanisms underlying cerebral blood flow regulation. While traveling through the different controversies that moved the research in this field, we keep a peculiar focus on those exploring the role of astrocytes in neurovascular coupling and conclude with two sections related to methodological aspects in neurovascular research and to some pathological conditions resulting in altered neurovascular coupling.
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Affiliation(s)
- Annamaria Lia
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
| | - Alessandro Di Spiezio
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | | | - Micaela Zonta
- Neuroscience Institute, National Research Council (CNR), Padua, Italy
- *Correspondence: Micaela Zonta,
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Wu C, Zou P, Feng S, Zhu L, Li F, Liu TCY, Duan R, Yang L. Molecular Hydrogen: an Emerging Therapeutic Medical Gas for Brain Disorders. Mol Neurobiol 2023; 60:1749-1765. [PMID: 36567361 DOI: 10.1007/s12035-022-03175-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 12/14/2022] [Indexed: 12/27/2022]
Abstract
Oxidative stress and neuroinflammation are the main physiopathological changes involved in the initiation and progression of various neurodegenerative disorders or brain injuries. Since the landmark finding reported in 2007 found that hydrogen reduced the levels of peroxynitrite anions and hydroxyl free radicals in ischemic stroke, molecular hydrogen's antioxidative and anti-inflammatory effects have aroused widespread interest. Due to its excellent antioxidant and anti-inflammatory properties, hydrogen therapy via different routes of administration exhibits great therapeutic potential for a wide range of brain disorders, including Alzheimer's disease, neonatal hypoxic-ischemic encephalopathy, depression, anxiety, traumatic brain injury, ischemic stroke, Parkinson's disease, and multiple sclerosis. This paper reviews the routes for hydrogen administration, the effects of hydrogen on the previously mentioned brain disorders, and the primary mechanism underlying hydrogen's neuroprotection. Finally, we discuss hydrogen therapy's remaining issues and challenges in brain disorders. We conclude that understanding the exact molecular target, finding novel routes, and determining the optimal dosage for hydrogen administration is critical for future studies and applications.
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Affiliation(s)
- Chongyun Wu
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Peibin Zou
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Shu Feng
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Ling Zhu
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Fanghui Li
- School of Sports Science, Nanjing Normal University, Nanjing, 210046, China
| | - Timon Cheng-Yi Liu
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Rui Duan
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China
| | - Luodan Yang
- Laboratory of Exercise and Neurobiology, School of Physical Education and Sports Science, South China Normal University, Guangzhou, 510006, China.
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7
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Burma JS, Rattana S, Johnson NE, Smirl JD. Do mean values tell the full story? Cardiac cycle and biological sex comparisons in temporally derived neurovascular coupling metrics. J Appl Physiol (1985) 2023; 134:426-443. [PMID: 36603050 DOI: 10.1152/japplphysiol.00170.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Previous reports have noted cerebrovascular regulation differs across the cardiac cycle, with greater regulation occurring within systole. However, this methodological notion has not been meticulously scrutinized during temporally deduced neurovascular coupling (NVC) metrics with additional respect to biological sex. Analyses of 111 healthy individuals (40 females/71 males) were performed where participants engaged in the "Where's Waldo?" paradigm. All NVC parameters were quantified in the posterior and middle cerebral arteries at 310 unique timepoints. Several individuals completed repeat testing which enabled for between-day (3 timepoints) and within-day (7 timepoints) reliability comparisons in 17 and 11 individuals, respectively. One-way analysis of variance compared NVC metrics between diastole, mean, and systole values, as well as differences between biological sexes. Greater absolute cerebral blood velocity (CBv; baseline and peak) and total activation (area under the curve) were noted within systole for both posterior cerebral artery (PCA; P < 0.001) and middle cerebral artery (MCA; P < 0.001) values; however, the relative percent increase in CBv was greater within diastole (P < 0.001). Females had an elevated diastolic and mean CBv and a greater diastolic cerebrovascular conductance (P < 0.050). No sex differences were present for systolic CBv measures and within parameters quantifying the NVC response (area under the curve/relative CBv increase) across the cardiac cycle (P > 0.072). Future investigations seeking to differentiate cerebral regulatory mechanisms between clinical populations may benefit by performing their analyses across the cardiac cycle, as certain pathogenesis may affect one aspect of the cardiac cycle independently. Minimal differences were noted between females and males for metrics characterizing the NVC response across the cardiac cycle.NEW & NOTEWORTHY Neurovascular coupling (NVC) studies commonly assess the mean cerebral hemodynamic response with little consideration for diastole, systole, and biological sex. Greater total activation expressed as the area under the curve was seen within systole compared with mean and diastole. Resting cerebral blood velocity sex differences were more prevalent during diastole when the cerebrovasculature was pressure-passive. Future studies should assess the NVC response across the cardiac cycle as it may help delineate the underlying pathophysiology of various clinical populations.
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Affiliation(s)
- Joel S Burma
- Faculty of Kinesiology, Cerebrovascular Concussion Lab, University of Calgary, Calgary, Alberta, Canada.,Faculty of Kinesiology, Sport Injury Prevention Research Centre, University of Calgary, Calgary, Alberta, Canada.,Faculty of Kinesiology, Human Performance Laboratory, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada
| | - Selina Rattana
- Faculty of Kinesiology, Cerebrovascular Concussion Lab, University of Calgary, Calgary, Alberta, Canada
| | - Nathan E Johnson
- Faculty of Kinesiology, Cerebrovascular Concussion Lab, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan D Smirl
- Faculty of Kinesiology, Cerebrovascular Concussion Lab, University of Calgary, Calgary, Alberta, Canada.,Faculty of Kinesiology, Sport Injury Prevention Research Centre, University of Calgary, Calgary, Alberta, Canada.,Faculty of Kinesiology, Human Performance Laboratory, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, Alberta, Canada
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8
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Burma JS, Van Roessel RK, Oni IK, Dunn JF, Smirl JD. Neurovascular coupling on trial: How the number of trials completed impacts the accuracy and precision of temporally derived neurovascular coupling estimates. J Cereb Blood Flow Metab 2022; 42:1478-1492. [PMID: 35209741 PMCID: PMC9274868 DOI: 10.1177/0271678x221084400] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Standard practices for quantifying neurovascular coupling (NVC) with transcranial Doppler ultrasound (TCD) require participants to complete one-to-ten repetitive trials. However, limited empirical evidence exists regarding how the number of trials completed influences the validity and reliability of temporally derived NVC metrics. Secondary analyses was performed on 60 young healthy participants (30 females/30 males) who completed eight cyclical eyes-closed (20-seconds), eyes-open (40-seconds) NVC trials, using the "Where's Waldo?" visual paradigm. TCD data was obtained in posterior and middle cerebral arteries (PCA and MCA, respectively). The within-day (n = 11) and between-day (n = 17) reliability were assessed at seven- and three-time points, respectively. Repeat testing from the reliability aims were also used for the concurrent validity analysis (n = 160). PCA metrics (i.e., baseline, peak, percent increase, and area-under-the-curve) demonstrated five trials produced excellent intraclass correlation coefficient (ICC) 95% confidence intervals for validity and within-day reliability (>0.900), whereas between-day reliability was good-to-excellent (>0.750). Likewise, 95% confidence intervals for coefficient of variation (CoV) measures ranged from acceptable (<20%) to excellent (<5%) with five-or-more trials. Employing fewer than five trials produced poor/unacceptable ICC and CoV metrics. Future NVC, TCD-based research should therefore have participants complete a minimum of five trials when quantifying the NVC response with TCD via a "Where's Waldo?" paradigm.
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Affiliation(s)
- Joel S Burma
- Cerebrovascular Concussion Lab, Faculty of Kinesiology, University of Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada
| | - Rowan K Van Roessel
- Cerebrovascular Concussion Lab, Faculty of Kinesiology, University of Calgary, Alberta, Canada
| | - Ibukunoluwa K Oni
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jeff F Dunn
- Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada.,Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.,Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jonathan D Smirl
- Cerebrovascular Concussion Lab, Faculty of Kinesiology, University of Calgary, Alberta, Canada.,Sport Injury Prevention Research Centre, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada.,Libin Cardiovascular Institute of Alberta, University of Calgary, Alberta, Canada.,Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.,Integrated Concussion Research Program, University of Calgary, Calgary, AB, Canada
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9
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Idesis S, Faskowitz J, Betzel RF, Corbetta M, Sporns O, Deco G. Edge-centric analysis of stroke patients: An alternative approach for biomarkers of lesion recovery. Neuroimage Clin 2022; 35:103055. [PMID: 35661469 PMCID: PMC9163596 DOI: 10.1016/j.nicl.2022.103055] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/17/2022]
Abstract
Most neuroimaging studies of post-stroke recovery rely on analyses derived from standard node-centric functional connectivity to map the distributed effects in stroke patients. Here, given the importance of nonlocal and diffuse damage, we use an edge-centric approach to functional connectivity in order to provide an alternative description of the effects of this disorder. These techniques allow for the rendering of metrics such as normalized entropy, which describes the diversity of edge communities at each node. Moreover, the approach enables the identification of high amplitude co-fluctuations in fMRI time series. We found that normalized entropy is associated with stroke lesion severity and continually increases across the time of patients' recovery. Furthermore, high amplitude co-fluctuations not only relate to the lesion severity but are also associated with patients' level of recovery. The current study is the first edge-centric application for a clinical population in a longitudinal dataset and demonstrates how a different perspective for functional data analysis can further characterize topographic modulations of brain dynamics.
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Affiliation(s)
- Sebastian Idesis
- Center for Brain and Cognition (CBC), Department of Information Technologies and Communications (DTIC), Pompeu Fabra University, Edifici Mercè Rodoreda, Carrer Trias i Fargas 25-27, 08005 Barcelona, Catalonia, Spain.
| | - Joshua Faskowitz
- Department of Psychological and Brain Science, Indiana University, Bloomington, IN 47405, United States; Program in Neuroscience, Indiana University, Bloomington, IN 47405, United States
| | - Richard F Betzel
- Department of Psychological and Brain Science, Indiana University, Bloomington, IN 47405, United States; Program in Neuroscience, Indiana University, Bloomington, IN 47405, United States; Cognitive Science Program, Indiana University, Bloomington, IN 47405, United States; Network Science Institute, Indiana University, Bloomington, IN 47405, United States
| | - Maurizio Corbetta
- Padova Neuroscience Center (PNC), University of Padova, via Orus 2/B, 35129 Padova, Italy; Department of Neuroscience (DNS), University of Padova, via Giustiniani 2, 35128 Padova, Italy; Department of Neurology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, United States; Department of Radiology, Washington University School of Medicine, 660 S. Euclid Ave, St. Louis, MO 63110, United States; VIMM, Venetian Institute of Molecular Medicine (VIMM), Biomedical Foundation, via Orus 2, 35129 Padova, Italy
| | - Olaf Sporns
- Department of Psychological and Brain Science, Indiana University, Bloomington, IN 47405, United States; Program in Neuroscience, Indiana University, Bloomington, IN 47405, United States; Cognitive Science Program, Indiana University, Bloomington, IN 47405, United States; Network Science Institute, Indiana University, Bloomington, IN 47405, United States
| | - Gustavo Deco
- Center for Brain and Cognition (CBC), Department of Information Technologies and Communications (DTIC), Pompeu Fabra University, Edifici Mercè Rodoreda, Carrer Trias i Fargas 25-27, 08005 Barcelona, Catalonia, Spain; Institució Catalana de Recerca I Estudis Avançats (ICREA), Passeig Lluis Companys 23, 08010 Barcelona, Catalonia, Spain
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10
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Li Z, McConnell HL, Stackhouse TL, Pike MM, Zhang W, Mishra A. Increased 20-HETE Signaling Suppresses Capillary Neurovascular Coupling After Ischemic Stroke in Regions Beyond the Infarct. Front Cell Neurosci 2021; 15:762843. [PMID: 34819839 PMCID: PMC8606525 DOI: 10.3389/fncel.2021.762843] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 10/06/2021] [Indexed: 12/23/2022] Open
Abstract
Neurovascular coupling, the process by which neuronal activity elicits increases in the local blood supply, is impaired in stroke patients in brain regions outside the infarct. Such impairment may contribute to neurological deterioration over time, but its mechanism is unknown. Using the middle cerebral artery occlusion (MCAO) model of stroke, we show that neuronal activity-evoked capillary dilation is reduced by ∼75% in the intact cortical tissue outside the infarct border. This decrease in capillary responsiveness was not explained by a decrease in local neuronal activity or a loss of vascular contractility. Inhibiting synthesis of the vasoconstrictive molecule 20-hydroxyeicosatetraenoic acid (20-HETE), either by inhibiting its synthetic enzyme CYP450 ω-hydroxylases or by increasing nitric oxide (NO), which is a natural inhibitor of ω-hydroxylases, rescued activity-evoked capillary dilation. The capillary dilation unmasked by inhibiting 20-HETE was dependent on PGE2 activation of endoperoxide 4 (EP4) receptors, a vasodilatory pathway previously identified in healthy animals. Cortical 20-HETE levels were increased following MCAO, in agreement with data from stroke patients. Inhibition of ω-hydroxylases normalized 20-HETE levels in vivo and increased cerebral blood flow in the peri-infarct cortex. These data identify 20-HETE-dependent vasoconstriction as a mechanism underlying capillary neurovascular coupling impairment after stroke. Our results suggest that the brain's energy supply may be significantly reduced after stroke in regions previously believed to be asymptomatic and that ω-hydroxylase inhibition may restore healthy neurovascular coupling post-stroke.
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Affiliation(s)
- Zhenzhou Li
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
- Department of Anesthesiology, General Hospital of Ningxia Medical University, Ningxia, China
| | - Heather L. McConnell
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Teresa L. Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Martin M. Pike
- Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, United States
| | - Wenri Zhang
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
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11
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Bader TJ, Leacy JK, Keough JRG, Ciorogariu‐Ivan A, Donald JR, Marullo AL, O’Halloran KD, Jendzjowsky NG, Wilson RJA, Day TA. The effects of acute incremental hypocapnia on the magnitude of neurovascular coupling in healthy participants. Physiol Rep 2021; 9:e14952. [PMID: 34350726 PMCID: PMC8339533 DOI: 10.14814/phy2.14952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Accepted: 04/17/2021] [Indexed: 12/03/2022] Open
Abstract
The high metabolic demand of cerebral tissue requires that local perfusion is tightly coupled with local metabolic rate (neurovascular coupling; NVC). During chronic altitude exposure, where individuals are exposed to the antagonistic cerebrovascular effects of hypoxia and hypocapnia, pH is maintained through renal compensation and NVC remains stable. However, the potential independent effect of acute hypocapnia and respiratory alkalosis on NVC remains to be determined. We hypothesized that acute steady-state hypocapnia via voluntary hyperventilation would attenuate the magnitude of NVC. We recruited 17 healthy participants and insonated the posterior cerebral artery (PCA) with transcranial Doppler ultrasound. NVC was elicited using a standardized strobe light stimulus (6 Hz; 5 × 30 s on/off) where absolute delta responses from baseline (BL) in peak, mean, and total area under the curve (tAUC) were quantified. From a BL end-tidal (PET )CO2 level of 36.7 ± 3.2 Torr, participants were coached to hyperventilate to reach steady-state hypocapnic steps of Δ-5 Torr (31.6 ± 3.9) and Δ-10 Torr (26.0 ± 4.0; p < 0.001), which were maintained during the presentation of the visual stimuli. We observed a small but significant reduction in NVC peak (ΔPCAv) from BL during controlled hypocapnia at both Δ-5 (-1.58 cm/s) and Δ-10 (-1.37 cm/s), but no significant decrease in mean or tAUC NVC response was observed. These data demonstrate that acute respiratory alkalosis attenuates peak NVC magnitude at Δ-5 and Δ-10 Torr PET CO2 , equally. Although peak NVC magnitude was mildly attenuated, our data illustrate that mean and tAUC NVC are remarkably stable during acute respiratory alkalosis, suggesting multiple mechanisms underlying NVC.
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Affiliation(s)
- Taylor J. Bader
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | - Jack K. Leacy
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Joanna R. G. Keough
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | | | - Joshua R. Donald
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | - Anthony L. Marullo
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
| | - Ken D. O’Halloran
- Department of PhysiologySchool of MedicineCollege of Medicine and HealthUniversity College CorkCorkIreland
| | - Nicholas G. Jendzjowsky
- Division of Respiratory and Critical Care Physiology and MedicineThe Lundquist Institute for Biomedical Innovation at Harbor‐UCLA Medical CenterTorranceCAUSA
| | - Richard J. A. Wilson
- Department of Physiology and PharmacologyHotchkiss Brain InstituteCumming School of MedicineUniversity of CalgaryCalgaryABCanada
| | - Trevor A. Day
- Department of BiologyFaculty of Science and TechnologyMount Royal UniversityCalgaryABCanada
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12
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Abstract
Neurovascular coupling is a crucial mechanism that matches the high energy demand of the brain with a supply of energy substrates from the blood. Signaling within the neurovascular unit is responsible for activity-dependent changes in cerebral blood flow. The strength and reliability of neurovascular coupling form the basis of non-invasive human neuroimaging techniques, including blood oxygen level dependent (BOLD) functional magnetic resonance imaging. Interestingly, BOLD signals are negative in infants, indicating a mismatch between metabolism and blood flow upon neural activation; this response is the opposite of that observed in healthy adults where activity evokes a large oversupply of blood flow. Negative neurovascular coupling has also been observed in rodents at early postnatal stages, further implying that this is a process that matures during development. This rationale is consistent with the morphological maturation of the neurovascular unit, which occurs over a similar time frame. While neurons differentiate before birth, astrocytes differentiate postnatally in rodents and the maturation of their complex morphology during the first few weeks of life links them with synapses and the vasculature. The vascular network is also incomplete in neonates and matures in parallel with astrocytes. Here, we review the timeline of the structural maturation of the neurovascular unit with special emphasis on astrocytes and the vascular tree and what it implies for functional maturation of neurovascular coupling. We also discuss similarities between immature astrocytes during development and reactive astrocytes in disease, which are relevant to neurovascular coupling. Finally, we close by pointing out current gaps in knowledge that must be addressed to fully elucidate the mechanisms underlying neurovascular coupling maturation, with the expectation that this may also clarify astrocyte-dependent mechanisms of cerebrovascular impairment in neurodegenerative conditions in which reduced or negative neurovascular coupling is noted, such as stroke and Alzheimer’s disease.
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Affiliation(s)
- Teresa L Stackhouse
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health & Science University, Portland, OR, United States.,Knight Cardiovascular Institute, Oregon Health & Sciences University, Portland, OR, United States
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13
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Shekhar S, Liu Y, Wang S, Zhang H, Fang X, Zhang J, Fan L, Zheng B, Roman RJ, Wang Z, Fan F, Booz GW. Novel Mechanistic Insights and Potential Therapeutic Impact of TRPC6 in Neurovascular Coupling and Ischemic Stroke. Int J Mol Sci 2021; 22:2074. [PMID: 33669830 PMCID: PMC7922996 DOI: 10.3390/ijms22042074] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/12/2021] [Accepted: 02/17/2021] [Indexed: 12/13/2022] Open
Abstract
Ischemic stroke is one of the most disabling diseases and a leading cause of death globally. Despite advances in medical care, the global burden of stroke continues to grow, as no effective treatments to limit or reverse ischemic injury to the brain are available. However, recent preclinical findings have revealed the potential role of transient receptor potential cation 6 (TRPC6) channels as endogenous protectors of neuronal tissue. Activating TRPC6 in various cerebral ischemia models has been found to prevent neuronal death, whereas blocking TRPC6 enhances sensitivity to ischemia. Evidence has shown that Ca2+ influx through TRPC6 activates the cAMP (adenosine 3',5'-cyclic monophosphate) response element-binding protein (CREB), an important transcription factor linked to neuronal survival. Additionally, TRPC6 activation may counter excitotoxic damage resulting from glutamate release by attenuating the activity of N-methyl-d-aspartate (NMDA) receptors of neurons by posttranslational means. Unresolved though, are the roles of TRPC6 channels in non-neuronal cells, such as astrocytes and endothelial cells. Moreover, TRPC6 channels may have detrimental effects on the blood-brain barrier, although their exact role in neurovascular coupling requires further investigation. This review discusses evidence-based cell-specific aspects of TRPC6 in the brain to assess the potential targets for ischemic stroke management.
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Affiliation(s)
- Shashank Shekhar
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Jin Zhang
- School of Medicine, I.M. Sechenov First Moscow State Medical University, Moscow 119048, Russia
| | - Letao Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Baoying Zheng
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Richard J. Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216, USA;
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
| | - George W. Booz
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, MS 39216, USA; (Y.L.); (S.W.); (H.Z.); (X.F.); (J.Z.); (L.F.); (B.Z.); (R.J.R.); (F.F.); (G.W.B.)
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14
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Mehler DMA, Williams AN, Whittaker JR, Krause F, Lührs M, Kunas S, Wise RG, Shetty HGM, Turner DL, Linden DEJ. Graded fMRI Neurofeedback Training of Motor Imagery in Middle Cerebral Artery Stroke Patients: A Preregistered Proof-of-Concept Study. Front Hum Neurosci 2020; 14:226. [PMID: 32760259 PMCID: PMC7373077 DOI: 10.3389/fnhum.2020.00226] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 05/20/2020] [Indexed: 02/04/2023] Open
Abstract
Ischemic stroke of the middle cerebral artery (MCA), a major brain vessel that supplies the primary motor and premotor cortex, is one of the most common causes for severe upper limb impairment. Currently available motor rehabilitation training largely lacks satisfying efficacy with over 70% of stroke survivors showing residual upper limb dysfunction. Motor imagery-based functional magnetic resonance imaging neurofeedback (fMRI-NF) has been suggested as a potential therapeutic technique to improve motor impairment in stroke survivors. In this preregistered proof-of-concept study (https://osf.io/y69jc/), we translated graded fMRI-NF training, a new paradigm that we have previously studied in healthy participants, to first-time MCA stroke survivors with residual mild to severe impairment of upper limb motor function. Neurofeedback was provided from the supplementary motor area (SMA) targeting two different neurofeedback target levels (low and high). We hypothesized that MCA stroke survivors will show (1) sustained SMA-region of interest (ROI) activation and (2) a difference in SMA-ROI activation between low and high neurofeedback conditions during graded fMRI-NF training. At the group level, we found only anecdotal evidence for these preregistered hypotheses. At the individual level, we found anecdotal to moderate evidence for the absence of the hypothesized graded effect for most subjects. These null findings are relevant for future attempts to employ fMRI-NF training in stroke survivors. The study introduces a Bayesian sequential sampling plan, which incorporates prior knowledge, yielding higher sensitivity. The sampling plan was preregistered together with a priori hypotheses and all planned analysis before data collection to address potential publication/researcher biases. Unforeseen difficulties in the translation of our paradigm to a clinical setting required some deviations from the preregistered protocol. We explicitly detail these changes, discuss the accompanied additional challenges that can arise in clinical neurofeedback studies, and formulate recommendations for how these can be addressed. Taken together, this work provides new insights about the feasibility of motor imagery-based graded fMRI-NF training in MCA stroke survivors and serves as a first example for comprehensive study preregistration of an (fMRI) neurofeedback experiment.
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Affiliation(s)
- David M. A. Mehler
- School of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, United Kingdom
- Department of Psychiatry, University of Münster, Münster, Germany
| | - Angharad N. Williams
- School of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, United Kingdom
- Max Planck Adaptive Memory Research Group, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany
| | - Joseph R. Whittaker
- School of Physics and Astronomy, Cardiff University, Cardiff, United Kingdom
| | - Florian Krause
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Department of Cognitive Neuroscience, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, Netherlands
| | - Michael Lührs
- Department of Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands
- Research Department, Brain Innovation B.V., Maastricht, Netherlands
| | - Stefanie Kunas
- School of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, United Kingdom
- Department of Psychiatry and Psychotherapy, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Richard G. Wise
- School of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, United Kingdom
- Department of Neuroscience, Imaging and Clinical Sciences, Institute for Advanced Biomedical Technologies, D'Annunzio University of Chieti–Pescara, Chieti, Italy
| | | | - Duncan L. Turner
- School of Health, Sport and Bioscience, University of East London, London, United Kingdom
| | - David E. J. Linden
- School of Psychology, Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff, United Kingdom
- Faculty of Health, Medicine and Life Sciences, School for Mental Health and Neuroscience, Maastricht University, Maastricht, Netherlands
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15
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Salinet AS, Silva NC, Caldas J, de Azevedo DS, de-Lima-Oliveira M, Nogueira RC, Conforto AB, Texeira MJ, Robinson TG, Panerai RB, Bor-Seng-Shu E. Impaired cerebral autoregulation and neurovascular coupling in middle cerebral artery stroke: Influence of severity? J Cereb Blood Flow Metab 2019; 39:2277-2285. [PMID: 30117360 PMCID: PMC6827118 DOI: 10.1177/0271678x18794835] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We aimed to assess cerebral autoregulation (CA) and neurovascular coupling (NVC) in stroke patients of differing severity comparing responses to healthy controls and explore the association between CA and NVC with functional outcome. Patients admitted with middle cerebral artery (MCA) stroke and healthy controls were recruited. Stroke severity was defined by the National Institutes of Health Stroke Scale (NIHSS) scores: ≤4 mild, 5-15 moderate and ≥16 severe. Transcranial Doppler ultrasound and Finometer recorded MCA cerebral blood flow velocity (CBFv) and blood pressure, respectively, over 5 min baseline and 1 min passive movement of the elbow to calculate the autoregulation index (ARI) and CBFv amplitude responses to movement. All participants were followed up for three months. A total of 87 participants enrolled in the study, including 15 mild, 27 moderate and 13 severe stroke patients, and 32 control subjects. ARI was lower in the affected hemisphere (AH) of moderate and severe stroke groups. Decreased NVC was seen bilaterally in all stroke groups. CA and NVC correlated with stroke severity and functional outcome. CBFv regulation is significantly impaired in acute stroke, and further compromised with increasing stroke severity. Preserved CA and NVC in the acute period were associated with improved three-month functional outcome.
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Affiliation(s)
- Angela Sm Salinet
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Nathália Cc Silva
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Juliana Caldas
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Daniel S de Azevedo
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Marcelo de-Lima-Oliveira
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Ricardo C Nogueira
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
| | - Adriana B Conforto
- Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil.,Brain Institute, Albert Einstein Israelite Hospital, São Paulo, Brazil
| | - Manoel J Texeira
- Engineering, Modelling and Applied Social Sciences Centre, Federal ABC University, Sao Bernardo do Campo, Sao Paulo, Brazil
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, Cerebral Haemodynamics in Ageing and Stroke Medicine Research Group, University of Leicester, Leicester, UK.,NIHR Leicester Biomedical Research Centre, University of Leicester, Leicester, UK
| | - Edson Bor-Seng-Shu
- Neurosurgical Division, Neurology Department, School of Medicine, University of São Paulo, Hospital das Clinicas, São Paulo, Brazil
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16
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Iyer PC, Rosenberg A, Baynard T, Madhavan S. Influence of neurovascular mechanisms on response to tDCS: an exploratory study. Exp Brain Res 2019; 237:2829-2840. [PMID: 31455998 DOI: 10.1007/s00221-019-05626-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/08/2019] [Indexed: 10/26/2022]
Abstract
The beneficial effects of transcranial direct current stimulation (tDCS) for stroke rehabilitation are limited by the variability in changes in corticomotor excitability (CME) after tDCS. Neuronal activity is closely related to cerebral blood flow; however, the cerebral hemodynamics of neuromodulation in relation to neural effects have been less explored. In this study, we examined the effects of tDCS on cerebral blood velocity (CBv) in chronic stroke survivors using transcranial Doppler (TCD) ultrasound in relation to changes in CME and described the neurovascular characteristics of tDCS responders. Middle cerebral artery (MCA) CBv, cerebrovascular resistance (CVRi) and other cerebral hemodynamics-related variables were continuously measured before and after 15 min of 1 mA anodal tDCS to the lesioned lower limb M1. tDCS did not modulate CBv in the whole group and upon TMS-based stratification of responders and non-responders. However, at baseline, responders demonstrated lower CME levels, lower CBv and higher CVRi as compared to non-responders. These results indicate a possible difference in baseline CME and CBv in tDCS responders that may influence their response to neuromodulation. Future trials with a large sample size and repeated baseline measurements may help validate these findings and establish a relationship between neuromodulation and neurovascular mechanisms in stroke.
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Affiliation(s)
- Pooja C Iyer
- Graduate Program in Rehabilitation Science, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Alexander Rosenberg
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA.,Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Tracy Baynard
- Integrative Physiology Laboratory, College of Applied Health Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | - Sangeetha Madhavan
- Brain Plasticity Laboratory, Department of Physical Therapy, College of Applied Health Sciences, University of Illinois at Chicago, 1919 West Taylor Street, Chicago, IL, 60612, USA.
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17
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Jokumsen-Cabral A, Aires A, Ferreira S, Azevedo E, Castro P. Primary involvement of neurovascular coupling in cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy. J Neurol 2019; 266:1782-8. [PMID: 31028544 DOI: 10.1007/s00415-019-09331-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 04/14/2019] [Accepted: 04/21/2019] [Indexed: 01/24/2023]
Abstract
BACKGROUND Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most frequent monogenic cause of cerebral ischemia, but reliable biomarkers to monitor the disease are lacking. AIMS AND OBJECTIVES To evaluate cerebral autoregulation (CA), vasoreactivity (VR), and neurovascular coupling (NVC) in CADASIL patients through a battery of dynamic transcranial Doppler tests. METHODS We screened our database for all pre-dementia CADASIL cases. We monitored cerebral blood flow velocity (CBFV) with transcranial Doppler, blood pressure, and expiratory carbon dioxide (CO2) non-invasively. CA was assessed by transfer function from the spontaneous oscillations of blood pressure to CBFV, VR with inhalation of CO2 at 5%, and hyperventilation and NVC by the CBFV response to visual stimulation. RESULTS We included 27 CADASIL patients and 20 healthy controls with similar age and sexes. CA and VR were similar between groups. However, NVC was significantly affected in CADASIL patients, with lower magnitudes of CBFV upsurge (overshoot 19 ± 5 vs 26 ± 6%, p = 0.013; gain 12 ± 7 vs 17 ± 5%, p = 0.003) and altered time behavior during visual stimulation (natural frequency 0.18 ± 0.06 vs 0.24 ± 0.06 Hz, p = 0.005; rate time 0.7 ± 1.7 vs 2.7 ± 3.5 s, p = 0.025). CONCLUSION Our results express a primary and selective involvement of the neurovascular unit in CADASIL rather than a generalized cerebral vasomotor disturbance. Functional cerebrovascular testing could be useful in patient evaluation and monitoring.
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18
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McConnell HL, Li Z, Woltjer RL, Mishra A. Astrocyte dysfunction and neurovascular impairment in neurological disorders: Correlation or causation? Neurochem Int 2019; 128:70-84. [PMID: 30986503 DOI: 10.1016/j.neuint.2019.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 04/08/2019] [Accepted: 04/09/2019] [Indexed: 12/14/2022]
Abstract
The neurovascular unit, consisting of neurons, astrocytes, and vascular cells, has become the focus of much discussion in the last two decades and emerging literature now suggests an association between neurovascular dysfunction and neurological disorders. In this review, we synthesize the known and suspected contributions of astrocytes to neurovascular dysfunction in disease. Throughout the brain, astrocytes are centrally positioned to dynamically mediate interactions between neurons and the cerebral vasculature, and play key roles in blood-brain barrier maintenance and neurovascular coupling. It is increasingly apparent that the changes in astrocytes in response to a variety of insults to brain tissue -collectively referred to as "reactive astrogliosis" - are not just an epiphenomenon restricted to morphological alterations, but comprise functional changes in astrocytes that contribute to the phenotype of neurological diseases with both beneficial and detrimental effects. In the context of the neurovascular unit, astrocyte dysfunction accompanies, and may contribute to, blood-brain barrier impairment and neurovascular dysregulation, highlighting the need to determine the exact nature of the relationship between astrocyte dysfunction and neurovascular impairments. Targeting astrocytes may represent a new strategy in combinatorial therapeutics for preventing the mismatch of energy supply and demand that often accompanies neurological disorders.
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Affiliation(s)
- Heather L McConnell
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States
| | - Zhenzhou Li
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States; Department of Anesthesiology, General Hospital of Ningxia Medical University, Yinchuan City, China
| | - Randall L Woltjer
- Department of Neuropathology, Oregon Health & Science University, Portland, OR, United States
| | - Anusha Mishra
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, United States.
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19
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Franzmeier N, Rubinski A, Neitzel J, Kim Y, Damm A, Na DL, Kim HJ, Lyoo CH, Cho H, Finsterwalder S, Duering M, Seo SW, Ewers M. Functional connectivity associated with tau levels in ageing, Alzheimer's, and small vessel disease. Brain 2019; 142:1093-1107. [PMID: 30770704 PMCID: PMC6439332 DOI: 10.1093/brain/awz026] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 11/27/2018] [Accepted: 12/21/2018] [Indexed: 12/14/2022] Open
Abstract
In Alzheimer's disease, tau pathology spreads hierarchically from the inferior temporal lobe throughout the cortex, ensuing cognitive decline and dementia. Similarly, circumscribed patterns of pathological tau have been observed in normal ageing and small vessel disease, suggesting a spatially ordered distribution of tau pathology across normal ageing and different diseases. In vitro findings suggest that pathological tau may spread 'prion-like' across neuronal connections in an activity-dependent manner. Supporting this notion, functional brain networks show a spatial correspondence to tau deposition patterns. However, it remains unclear whether higher network-connectivity facilitates tau propagation. To address this, we included 55 normal aged elderly (i.e. cognitively normal, amyloid-negative), 50 Alzheimer's disease patients (i.e. amyloid-positive) covering the preclinical to dementia spectrum, as well as 36 patients with pure (i.e. amyloid-negative) vascular cognitive impairment due to small vessel disease. All subjects were assessed with AV1451 tau-PET and resting-state functional MRI. Within each group, we computed atlas-based resting-state functional MRI functional connectivity across 400 regions of interest covering the entire neocortex. Using the same atlas, we also assessed within each group the covariance of tau-PET levels among the 400 regions of interest. We found that higher resting-state functional MRI assessed functional connectivity between any given region of interest pair was associated with higher covariance in tau-PET binding in corresponding regions of interest. This result was consistently found in normal ageing, Alzheimer's disease and vascular cognitive impairment. In particular, inferior temporal tau-hotspots, as defined by highest tau-PET uptake, showed high predictive value of tau-PET levels in functionally closely connected regions of interest. These associations between functional connectivity and tau-PET uptake were detected regardless of presence of dementia symptoms (mild cognitive impairment or dementia), amyloid deposition (as assessed by amyloid-PET) or small vessel disease. Our findings suggest that higher functional connectivity between brain regions is associated with shared tau-levels, supporting the view of prion-like tau spreading facilitated by neural activity.
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Affiliation(s)
- Nicolai Franzmeier
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Anna Rubinski
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Julia Neitzel
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Yeshin Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Department of Neurology, Kangwon National University Hospital, Kangwon National University College of Medicine, Chuncheon, Republic of Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Alexander Damm
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Duk L Na
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
- Department of Health Sciences and Technology, Samsung Advanced Institute of Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
| | - Hee Jin Kim
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
| | - Chul Hyoung Lyoo
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Hana Cho
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Sofia Finsterwalder
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Marco Duering
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
| | - Sang Won Seo
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea
- Neuroscience Center, Samsung Medical Center, Seoul, Korea
- Department of Clinical Research Design and Evaluation, Samsung Advanced Institute of Health Sciences and Technology, Sungkyunkwan University, Seoul, Korea
- Center for Imaging of Neurodegenerative Diseases, University of California, San Francisco
| | - Michael Ewers
- Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians-Universität LMU, Feodor-Lynen Straße 17, Munich, Germany
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Abstract
Comorbidities are a hallmark of stroke that both increase the incidence of stroke and worsen outcome. Hypertension is prevalent in the stroke population and the most important modifiable risk factor for stroke. Hypertensive disorders promote stroke through increased shear stress, endothelial dysfunction, and large artery stiffness that transmits pulsatile flow to the cerebral microcirculation. Hypertension also promotes cerebral small vessel disease through several mechanisms, including hypoperfusion, diminished autoregulatory capacity and localized increase in blood-brain barrier permeability. Preeclampsia, a hypertensive disorder of pregnancy, also increases the risk of stroke 4-5-fold compared to normal pregnancy that predisposes women to early-onset cognitive impairment. In this review, we highlight how comorbidities and concomitant disorders are not only risk factors for ischemic stroke, but alter the response to acute ischemia. We focus on hypertension as a comorbidity and its effects on the cerebral circulation that alters the pathophysiology of ischemic stroke and should be considered in guiding future therapeutic strategies.
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Affiliation(s)
- Marilyn J Cipolla
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - David S Liebeskind
- 2 Neurovascular Imaging Research Core and Stroke Center, Department of Neurology, University of California at Los Angeles, Los Angeles, CA, USA
| | - Siu-Lung Chan
- 1 Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
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Iyer PC, Madhavan S. Non-invasive brain stimulation in the modulation of cerebral blood flow after stroke: A systematic review of Transcranial Doppler studies. Clin Neurophysiol 2018; 129:2544-51. [PMID: 30384025 DOI: 10.1016/j.clinph.2018.09.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/13/2018] [Accepted: 09/18/2018] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Non-invasive brain stimulation (NIBS), such as repetitive TMS (rTMS) and transcranial direct current stimulation (tDCS), are promising neuromodulatory priming techniques to promote task-specific functional recovery after stroke. Despite promising results, clinical application of NIBS has been limited by high inter-individual variability. We propose that there is a possible influence of neuromodulation on cerebral blood flow (CBF), as neurons are spatially and temporally related to blood vessels. Transcranial Doppler (TCD), a clinically available non-invasive diagnostic tool, allows for evaluation of CBF velocity (CBFv). However, little is known about the role of neuromodulation on CBFv. METHODS A systematic review of literature to understand the effects of NIBS on CBFv using TCD in stroke was conducted. RESULTS Twelve studies fit our inclusion criteria and are included in this review. Our review suggested that CBFv and/or vasomotor reactivity maybe influenced by rTMS dosage (intensity and frequency) and the type of tDCS electrode montage. CONCLUSION There is limited evidence regarding the effects of NIBS on cerebral hemodynamics using TCD and the usefulness of TCD to capture changes in CBFv after NIBS is not evident from this review. We highlight the variability in the experimental protocols, differences in the applied neurostimulation protocols and discuss open questions that remain regarding CBF and neuromodulation. SIGNIFICANCE TCD, a clinically accessible tool, may potentially be useful to understand the interaction between cortical neuromodulation and CBFv.
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Love S, Miners JS. Small vessel disease, neurovascular regulation and cognitive impairment: post-mortem studies reveal a complex relationship, still poorly understood. Clin Sci (Lond) 2017; 131:1579-1589. [PMID: 28667060 DOI: 10.1042/cs20170148] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 11/08/2023]
Abstract
The contribution of vascular disease to cognitive impairment is under-recognized and the pathogenesis is poorly understood. This information gap has multiple causes, including a lack of post-mortem validation of clinical diagnoses of vascular cognitive impairment (VCI) or vascular dementia (VaD), the exclusion of cases with concomitant neurodegenerative disease when diagnosing VCI/VaD, and a lack of standardization of neuropathological assessment protocols for vascular disease. Other contributors include a focus on end-stage destructive lesions to the exclusion of more subtle types of diffuse brain injury, on structural abnormalities of arteries and arterioles to the exclusion of non-structural abnormalities and capillary damage, and the use of post-mortem sampling strategies that are biased towards the identification of neurodegenerative pathologies. Recent studies have demonstrated the value of detailed neuropathology in characterizing vascular contributions to cognitive impairment (e.g. in diabetes), and highlight the importance of diffuse white matter changes, capillary damage and vasoregulatory abnormalities in VCI/VaD. The use of standardized, evidence-based post-mortem assessment protocols and the inclusion of biochemical as well as morphological methods in neuropathological studies should improve the accuracy of determination of the contribution of vascular disease to cognitive impairment and clarify the relative contribution of different pathogenic processes to the tissue damage.
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Affiliation(s)
- Seth Love
- Dementia Research Group, School of Clinical Sciences, University of Bristol, Learning and Research Level 1, Southmead Hospital, Bristol BS10 5NB, U.K.
| | - J Scott Miners
- Dementia Research Group, School of Clinical Sciences, University of Bristol, Learning and Research Level 1, Southmead Hospital, Bristol BS10 5NB, U.K
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Berg RMG. Myogenic and metabolic feedback in cerebral autoregulation: Putative involvement of arachidonic acid-dependent pathways. Med Hypotheses 2016; 92:12-7. [PMID: 27241246 DOI: 10.1016/j.mehy.2016.04.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/09/2016] [Accepted: 04/13/2016] [Indexed: 01/20/2023]
Abstract
The present paper presents a mechanistic model of cerebral autoregulation, in which the dual effects of the arachidonic acid metabolites 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) on vascular smooth muscle mediate the cerebrovascular adjustments to a change in cerebral perfusion pressure (CPP). 20-HETE signalling in vascular smooth muscle mediates myogenic feedback to changes in vessel wall stretch, which may be modulated by metabolic feedback through EETs released from astrocytes and endothelial cells in response to changes in brain tissue oxygen tension. The metabolic feedback pathway is much faster than 20-HETE-dependent myogenic feedback, and the former thus initiates the cerebral autoregulatory response, while myogenic feedback comprises a relatively slower mechanism that functions to set the basal cerebrovascular tone. Therefore, assessments of dynamic cerebral autoregulation, which may provide information on the response time of the cerebrovasculature, may specifically be used to yield information on metabolic feedback mechanisms, while data based on assessments of static cerebral autoregulation represent the integrated functionality of myogenic and metabolic feedback.
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Affiliation(s)
- Ronan M G Berg
- Department of Clinical Physiology & Nuclear Medicine, Frederiksberg and Bispebjerg Hospitals, Frederiksberg, Denmark.
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Slack R, Boorman L, Patel P, Harris S, Bruyns-Haylett M, Kennerley A, Jones M, Berwick J. A novel method for classifying cortical state to identify the accompanying changes in cerebral hemodynamics. J Neurosci Methods 2016; 267:21-34. [PMID: 27063501 PMCID: PMC4896992 DOI: 10.1016/j.jneumeth.2016.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 03/29/2016] [Accepted: 04/06/2016] [Indexed: 11/27/2022]
Abstract
We classified brain state using a vector-based categorisation of neural frequencies. Changes in cerebral blood volume (CBV) were observed when brain state altered. During these state alterations, changes in blood oxygenation were also found. State dependent haemodynamic changes could affect blood based brain imaging.
Background Many brain imaging techniques interpret the haemodynamic response as an indirect indicator of underlying neural activity. However, a challenge when interpreting this blood based signal is how changes in brain state may affect both baseline and stimulus evoked haemodynamics. New method We developed an Automatic Brain State Classifier (ABSC), validated on data from anaesthetised rodents. It uses vectorised information obtained from the windowed spectral frequency power of the Local Field Potential. Current state is then classified by comparing this vectorised information against that calculated from state specific training datasets. Results The ABSC identified two user defined brain states (synchronised and desynchronised), with high accuracy (∼90%). Baseline haemodynamics were found to be significantly different in the two identified states. During state defined periods of elevated baseline haemodynamics we found significant decreases in evoked haemodynamic responses to somatosensory stimuli. Comparison to existing methods State classification – The ABSC (∼90%) demonstrated greater accuracy than clustering (∼66%) or ‘power threshold’ (∼64%) methods of comparison. Haemodynamic averaging – Our novel approach of selectively averaging stimulus evoked haemodynamic trials by brain state yields higher quality data than creating a single average from all trials. Conclusions The ABSC can account for some of the commonly observed trial-to-trial variability in haemodynamic responses which arises from changes in cortical state. This variability might otherwise be incorrectly attributed to alternative interpretations. A greater understanding of the effects of cortical state on haemodynamic changes could be used to inform techniques such as general linear modelling (GLM), commonly used in fMRI.
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Affiliation(s)
- R Slack
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - L Boorman
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - P Patel
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - S Harris
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - M Bruyns-Haylett
- Department of Systems Engineering, University of Reading, Whiteknights, Reading RG6 6AY, United Kingdom.
| | - A Kennerley
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - M Jones
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
| | - J Berwick
- Department of Psychology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom.
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Huneau C, Benali H, Chabriat H. Investigating Human Neurovascular Coupling Using Functional Neuroimaging: A Critical Review of Dynamic Models. Front Neurosci 2015; 9:467. [PMID: 26733782 PMCID: PMC4683196 DOI: 10.3389/fnins.2015.00467] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Accepted: 11/23/2015] [Indexed: 01/26/2023] Open
Abstract
The mechanisms that link a transient neural activity to the corresponding increase of cerebral blood flow (CBF) are termed neurovascular coupling (NVC). They are possibly impaired at early stages of small vessel or neurodegenerative diseases. Investigation of NVC in humans has been made possible with the development of various neuroimaging techniques based on variations of local hemodynamics during neural activity. Specific dynamic models are currently used for interpreting these data that can include biophysical parameters related to NVC. After a brief review of the current knowledge about possible mechanisms acting in NVC we selected seven models with explicit integration of NVC found in the literature. All these models were described using the same procedure. We compared their physiological assumptions, mathematical formalism, and validation. In particular, we pointed out their strong differences in terms of complexity. Finally, we discussed their validity and their potential applications. These models may provide key information to investigate various aspects of NVC in human pathology.
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Affiliation(s)
- Clément Huneau
- Laboratoire d'Imagerie Biomédicale, UPMC Paris 06, Centre National de la Recherche Scientifique U7371, Institut National de la Santé et de la Recherche Médicale U1146, Sorbonne UniversitésParis, France; Institut National de la Santé et de la Recherche Médicale U1161, Université Paris Diderot, Sorbonne Paris CitéParis, France
| | - Habib Benali
- Laboratoire d'Imagerie Biomédicale, UPMC Paris 06, Centre National de la Recherche Scientifique U7371, Institut National de la Santé et de la Recherche Médicale U1146, Sorbonne Universités Paris, France
| | - Hugues Chabriat
- Institut National de la Santé et de la Recherche Médicale U1161, Université Paris Diderot, Sorbonne Paris CitéParis, France; AP-HP, Hôpital Lariboisière, Service de Neurologie and DHU NeuroVascParis, France
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Abstract
SIGNIFICANCE The brain has high energetic requirements and is therefore highly dependent on adequate cerebral blood supply. To compensate for dangerous fluctuations in cerebral perfusion, the circulation of the brain has evolved intrinsic safeguarding measures. RECENT ADVANCES AND CRITICAL ISSUES The vascular network of the brain incorporates a high degree of redundancy, allowing the redirection and redistribution of blood flow in the event of vascular occlusion. Furthermore, active responses such as cerebral autoregulation, which acts to maintain constant cerebral blood flow in response to changing blood pressure, and functional hyperemia, which couples blood supply with synaptic activity, allow the brain to maintain adequate cerebral perfusion in the face of varying supply or demand. In the presence of stroke risk factors, such as hypertension and diabetes, these protective processes are impaired and the susceptibility of the brain to ischemic injury is increased. One potential mechanism for the increased injury is that collateral flow arising from the normally perfused brain and supplying blood flow to the ischemic region is suppressed, resulting in more severe ischemia. FUTURE DIRECTIONS Approaches to support collateral flow may ameliorate the outcome of focal cerebral ischemia by rescuing cerebral perfusion in potentially viable regions of the ischemic territory.
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Affiliation(s)
- Katherine Jackman
- Brain and Mind Research Institute, Weill Cornell Medical College , New York, New York
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Veldsman M, Cumming T, Brodtmann A. Beyond BOLD: optimizing functional imaging in stroke populations. Hum Brain Mapp 2014; 36:1620-36. [PMID: 25469481 DOI: 10.1002/hbm.22711] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 11/14/2014] [Accepted: 11/25/2014] [Indexed: 12/11/2022] Open
Abstract
Blood oxygenation level-dependent (BOLD) signal changes are often assumed to directly reflect neural activity changes. Yet the real relationship is indirect, reliant on numerous assumptions, and subject to several sources of noise. Deviations from the core assumptions of BOLD contrast functional magnetic resonance imaging (fMRI), and their implications, have been well characterized in healthy populations, but are frequently neglected in stroke populations. In addition to conspicuous local structural and vascular changes after stroke, there are many less obvious challenges in the imaging of stroke populations. Perilesional ischemic changes, remodeling in regions distant to lesion sites, and diffuse perfusion changes all complicate interpretation of BOLD signal changes in standard fMRI protocols. Most stroke patients are also older than the young populations on which assumptions of neurovascular coupling and the typical analysis pipelines are based. We present a review of the evidence to show that the basic assumption of neurovascular coupling on which BOLD-fMRI relies does not capture the complex changes arising from stroke, both pathological and recovery related. As a result, estimating neural activity using the canonical hemodynamic response function is inappropriate in a number of contexts. We review methods designed to better estimate neural activity in stroke populations. One promising alternative to event-related fMRI is a resting-state-derived functional connectivity approach. Resting-state fMRI is well suited to stroke populations because it makes no performance demands on patients and is capable of revealing network-based pathology beyond the lesion site.
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Affiliation(s)
- Michele Veldsman
- The Florey Institute for Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
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Martin C. Contributions and complexities from the use of in vivo animal models to improve understanding of human neuroimaging signals. Front Neurosci 2014; 8:211. [PMID: 25191214 PMCID: PMC4137227 DOI: 10.3389/fnins.2014.00211] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 07/01/2014] [Indexed: 01/18/2023] Open
Abstract
Many of the major advances in our understanding of how functional brain imaging signals relate to neuronal activity over the previous two decades have arisen from physiological research studies involving experimental animal models. This approach has been successful partly because it provides opportunities to measure both the hemodynamic changes that underpin many human functional brain imaging techniques and the neuronal activity about which we wish to make inferences. Although research into the coupling of neuronal and hemodynamic responses using animal models has provided a general validation of the correspondence of neuroimaging signals to specific types of neuronal activity, it is also highlighting the key complexities and uncertainties in estimating neural signals from hemodynamic markers. This review will detail how research in animal models is contributing to our rapidly evolving understanding of what human neuroimaging techniques tell us about neuronal activity. It will highlight emerging issues in the interpretation of neuroimaging data that arise from in vivo research studies, for example spatial and temporal constraints to neuroimaging signal interpretation, or the effects of disease and modulatory neurotransmitters upon neurovascular coupling. We will also give critical consideration to the limitations and possible complexities of translating data acquired in the typical animals models used in this area to the arena of human fMRI. These include the commonplace use of anesthesia in animal research studies and the fact that many neuropsychological questions that are being actively explored in humans have limited homologs within current animal models for neuroimaging research. Finally we will highlighting approaches, both in experimental animals models (e.g. imaging in conscious, behaving animals) and human studies (e.g. combined fMRI-EEG), that mitigate against these challenges.
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Affiliation(s)
- Chris Martin
- Department of Psychology, The University of Sheffield Sheffield, UK
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Salinet ASM, Robinson TG, Panerai RB. Cerebral blood flow response to neural activation after acute ischemic stroke: a failure of myogenic regulation? J Neurol 2013; 260:2588-95. [PMID: 23824356 DOI: 10.1007/s00415-013-7022-z] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/17/2013] [Accepted: 06/23/2013] [Indexed: 12/19/2022]
Abstract
We tested two hypotheses: (1) neurovascular coupling is impaired after acute ischemic stroke, (2) subcomponent analysis of cerebral blood flow velocity can reveal significant differences between acute ischemic stroke and healthy controls. This was explored through the comparison of nineteen acute ischemic stroke patients with healthy controls. Recordings of cerebral blood flow velocity, blood pressure and end-tidal CO2 were obtained during 60s of passive elbow flexion. Cerebral blood flow velocity changes were decomposed into standardized subcomponents describing the contributions of blood pressure (V BP), resistance area product (V RAP) and critical closing pressure (V CrCP). The passive paradigm led to a bilateral cerebral blood flow velocity increase in both groups, but in acute ischemic stroke the magnitude of change was significantly lower. Blood pressure increases were shown to be an important contributor to cerebral blood flow velocity response throughout the paradigm in both groups, with no significant difference between groups. The V CrCP contribution was not different between groups or hemispheres; its continuous rise during activation indicating a vasodilatory effect. On the other hand, the V RAP contribution showed significant differences (p = 0.03), thus suggesting myogenic impairment in acute ischemic stroke. Cerebral blood flow velocity responses to passive elbow flexion suggest an impairment of neurovascular coupling in acute ischemic stroke. Subcomponent analysis suggests an impairment of the myogenic pathways, giving a greater insight into the different mechanisms contributing to neurovascular coupling. Further research is needed to assess the clinical value of subcomponent analysis of neurovascular coupling and the natural history of such changes following acute ischemic stroke.
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Affiliation(s)
- Angela S M Salinet
- Department of Cardiovascular Sciences, University of Leicester, Trent Stroke Research Network Office, Victoria Building, Leicester Royal Infirmary, LE1 5WW, Leicester, UK,
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Kowiański P, Lietzau G, Steliga A, Waśkow M, Moryś J. The astrocytic contribution to neurovascular coupling – Still more questions than answers? Neurosci Res 2013; 75:171-83. [DOI: 10.1016/j.neures.2013.01.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 12/15/2012] [Accepted: 12/30/2012] [Indexed: 01/03/2023]
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Salinet ASM, Haunton VJ, Panerai RB, Robinson TG. A systematic review of cerebral hemodynamic responses to neural activation following stroke. J Neurol 2013; 260:2715-21. [DOI: 10.1007/s00415-013-6836-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
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Castro P, Santos R, Freitas J, Rosengarten B, Panerai R, Azevedo E. Adaptation of cerebral pressure-velocity hemodynamic changes of neurovascular coupling to orthostatic challenge. ACTA ACUST UNITED AC 2012. [DOI: 10.1016/j.permed.2012.02.052] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Fabjan A, Musizza B, Bajrović FF, Zaletel M, Strucl M. The effect of the cold pressor test on a visually evoked cerebral blood flow velocity response. Ultrasound Med Biol 2012; 38:13-20. [PMID: 22104537 DOI: 10.1016/j.ultrasmedbio.2011.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Revised: 08/17/2011] [Accepted: 10/12/2011] [Indexed: 05/31/2023]
Abstract
We investigated the hypothesis that during tonic pain stimulus, neurovascular coupling (NVC) decreases, measuring visually evoked cerebral blood flow velocity response (VEFR) during cold pressor test (CPT) in healthy human subjects as a test. VEFR was calculated as a relative increase in blood flow velocity in the posterior cerebral artery from average values during the last 5 s of the stimulus-OFF period to average values during the last 10 s of the stimulus-ON period. Three consecutive experimental phases were compared: basal, CPT and recovery. During CPT, end-diastolic and mean VEFR increased from 20.2 to 23.6% (p < 0.05) and from 17.5 to 20.0% (p < 0.05), respectively. In recovery phase, end-diastolic and mean VEFR decreased to 17.7% and 15.5%, respectively. Both values were statistically significantly different from CPT phase (p < 0.05). Compared with the basal phase, only end-diastolic VEFR was statistically significantly different in the recovery phase (p < 0.05). Our results are consistent with the assumption that there is a change in the activity of NVC during CPT because of the modulatory influence of subcortical structures activated during tonic pain. Contrary to our expectations, the combined effect of such influences increases rather than decreases NVC.
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Affiliation(s)
- Andrej Fabjan
- Institute of Physiology, Medical Faculty, University of Ljubljana, Ljubljana, Slovenia.
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