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Cerri DH, Albaugh DL, Walton LR, Katz B, Wang TW, Chao THH, Zhang W, Nonneman RJ, Jiang J, Lee SH, Etkin A, Hall CN, Stuber GD, Shih YYI. Distinct neurochemical influences on fMRI response polarity in the striatum. Nat Commun 2024; 15:1916. [PMID: 38429266 PMCID: PMC10907631 DOI: 10.1038/s41467-024-46088-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 02/13/2024] [Indexed: 03/03/2024] Open
Abstract
The striatum, known as the input nucleus of the basal ganglia, is extensively studied for its diverse behavioral roles. However, the relationship between its neuronal and vascular activity, vital for interpreting functional magnetic resonance imaging (fMRI) signals, has not received comprehensive examination within the striatum. Here, we demonstrate that optogenetic stimulation of dorsal striatal neurons or their afferents from various cortical and subcortical regions induces negative striatal fMRI responses in rats, manifesting as vasoconstriction. These responses occur even with heightened striatal neuronal activity, confirmed by electrophysiology and fiber-photometry. In parallel, midbrain dopaminergic neuron optogenetic modulation, coupled with electrochemical measurements, establishes a link between striatal vasodilation and dopamine release. Intriguingly, in vivo intra-striatal pharmacological manipulations during optogenetic stimulation highlight a critical role of opioidergic signaling in generating striatal vasoconstriction. This observation is substantiated by detecting striatal vasoconstriction in brain slices after synthetic opioid application. In humans, manipulations aimed at increasing striatal neuronal activity likewise elicit negative striatal fMRI responses. Our results emphasize the necessity of considering vasoactive neurotransmission alongside neuronal activity when interpreting fMRI signal.
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Affiliation(s)
- Domenic H Cerri
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Daniel L Albaugh
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Lindsay R Walton
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Brittany Katz
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Wen Wang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Tzu-Hao Harry Chao
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Weiting Zhang
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Randal J Nonneman
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Jing Jiang
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Department of Pediatrics, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Department of Psychiatry, University of Iowa Carver College of Medicine, Iowa City, IA, USA
- Iowa Neuroscience Institute, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Sung-Ho Lee
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Amit Etkin
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Wu Tsai Neurosciences Institute, Stanford University, Stanford, CA, USA
- Alto Neuroscience, Los Altos, CA, USA
| | - Catherine N Hall
- Sussex Neuroscience, University of Sussex, Falmer, United Kingdom
- School of Psychology, University of Sussex, Falmer, United Kingdom
| | - Garret D Stuber
- Center for Neurobiology of Addiction, Pain, and Emotion, University of Washington, Seattle, WA, USA
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, USA
- Department of Pharmacology, University of Washington, Seattle, WA, USA
| | - Yen-Yu Ian Shih
- Center for Animal MRI, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Biomedical Research Imaging Center, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- Department of Neurology, the University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
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2
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Wakid M, Almeida D, Aouabed Z, Rahimian R, Davoli MA, Yerko V, Leonova-Erko E, Richard V, Zahedi R, Borchers C, Turecki G, Mechawar N. Universal method for the isolation of microvessels from frozen brain tissue: A proof-of-concept multiomic investigation of the neurovasculature. Brain Behav Immun Health 2023; 34:100684. [PMID: 37822873 PMCID: PMC10562768 DOI: 10.1016/j.bbih.2023.100684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 10/13/2023] Open
Abstract
The neurovascular unit, comprised of vascular cell types that collectively regulate cerebral blood flow to meet the needs of coupled neurons, is paramount for the proper function of the central nervous system. The neurovascular unit gatekeeps blood-brain barrier properties, which experiences impairment in several central nervous system diseases associated with neuroinflammation and contributes to pathogenesis. To better understand function and dysfunction at the neurovascular unit and how it may confer inflammatory processes within the brain, isolation and characterization of the neurovascular unit is needed. Here, we describe a singular, standardized protocol to enrich and isolate microvessels from archived snap-frozen human and frozen mouse cerebral cortex using mechanical homogenization and centrifugation-separation that preserves the structural integrity and multicellular composition of microvessel fragments. For the first time, microvessels are isolated from postmortem ventromedial prefrontal cortex tissue and are comprehensively investigated as a structural unit using both RNA sequencing and Liquid Chromatography with tandem mass spectrometry (LC-MS/MS). Both the transcriptome and proteome are obtained and compared, demonstrating that the isolated brain microvessel is a robust model for the NVU and can be used to generate highly informative datasets in both physiological and disease contexts.
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Affiliation(s)
- Marina Wakid
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Daniel Almeida
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
| | - Zahia Aouabed
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
| | - Reza Rahimian
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
| | | | - Volodymyr Yerko
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
| | - Elena Leonova-Erko
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
| | - Vincent Richard
- Segal Cancer Proteomics Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, Quebec, Canada
| | - René Zahedi
- Segal Cancer Proteomics Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, Quebec, Canada
| | - Christoph Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute for Medical Research, Jewish General Hospital, McGill University, Montréal, Quebec, Canada
| | - Gustavo Turecki
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
- Department of Psychiatry, McGill University, Montréal, Quebec, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Research Centre, Montréal, Quebec, Canada
- Integrated Program in Neuroscience, McGill University, Montréal, Quebec, Canada
- Department of Psychiatry, McGill University, Montréal, Quebec, Canada
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3
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Katz BM, Walton LR, Houston KM, Cerri DH, Shih YYI. Putative neurochemical and cell type contributions to hemodynamic activity in the rodent caudate putamen. J Cereb Blood Flow Metab 2023; 43:481-498. [PMID: 36448509 PMCID: PMC10063835 DOI: 10.1177/0271678x221142533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/28/2022] [Accepted: 10/21/2022] [Indexed: 12/02/2022]
Abstract
Functional magnetic resonance imaging (fMRI) is widely used by researchers to noninvasively monitor brain-wide activity. The traditional assumption of a uniform relationship between neuronal and hemodynamic activity throughout the brain has been increasingly challenged. This relationship is now believed to be impacted by heterogeneously distributed cell types and neurochemical signaling. To date, most cell-type- and neurotransmitter-specific influences on hemodynamics have been examined within the cortex and hippocampus of rodent models, where glutamatergic signaling is prominent. However, neurochemical influences on hemodynamics are relatively unknown in largely GABAergic brain regions such as the rodent caudate putamen (CPu). Given the extensive contribution of CPu function and dysfunction to behavior, and the increasing focus on this region in fMRI studies, improved understanding of CPu hemodynamics could have broad impacts. Here we discuss existing findings on neurochemical contributions to hemodynamics as they may relate to the CPu with special consideration for how these contributions could originate from various cell types and circuits. We hope this review can help inform the direction of future studies as well as interpretation of fMRI findings in the CPu.
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Affiliation(s)
- Brittany M Katz
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Lindsay R Walton
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Kaiulani M Houston
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, USA
| | - Domenic H Cerri
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yen-Yu Ian Shih
- Neuroscience Curriculum, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Center for Animal MRI, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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4
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Modulation of Visual Responses and Ocular Dominance by Contralateral Inhibitory Activation in the Mouse Visual Cortex. Int J Mol Sci 2023; 24:ijms24065750. [PMID: 36982823 PMCID: PMC10058019 DOI: 10.3390/ijms24065750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/12/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
Both hemispheres connect with each other by excitatory callosal projections, and whether inhibitory interneurons, usually believed to have local innervation, engage in transcallosal activity modulation is unknown. Here, we used optogenetics in combination with cell-type-specific channelrhodopsin-2 expression to activate different inhibitory neuron subpopulations in the visual cortex and recorded the response of the entire visual cortex using intrinsic signal optical imaging. We found that optogenetic stimulation of inhibitory neurons reduced spontaneous activity (increase in the reflection of illumination) in the binocular area of the contralateral hemisphere, although these stimulations had different local effects ipsilaterally. The activation of contralateral interneurons differentially affected both eye responses to visual stimuli and, thus, changed ocular dominance. Optogenetic silencing of excitatory neurons affects the ipsilateral eye response and ocular dominance in the contralateral cortex to a lesser extent. Our results revealed a transcallosal effect of interneuron activation in the mouse visual cortex.
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5
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Aksenov DP, Li L, Serdyukova NA, Gascoigne DA, Doubovikov ED, Drobyshevsky A. Functional Deficiency of Interneurons and Negative BOLD fMRI Response. Cells 2023; 12:cells12050811. [PMID: 36899947 PMCID: PMC10000915 DOI: 10.3390/cells12050811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/20/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
The functional deficiency of the inhibitory system typically appears during development and can progress to psychiatric disorders or epilepsy, depending on its severity, in later years. It is known that interneurons, the major source of GABAergic inhibition in the cerebral cortex, can make direct connections with arterioles and participate in the regulation of vasomotion. The goal of this study was to mimic the functional deficiency of interneurons through the use of localized microinjections of the GABA antagonist, picrotoxin, in such a concentration that it did not elicit epileptiform neuronal activity. First, we recorded the dynamics of resting-state neuronal activity in response to picrotoxin injections in the somatosensory cortex of an awake rabbit; second, we assessed the altered neuronal and hemodynamic responses to whisker stimulation using BOLD fMRI and electrophysiology recordings; third, we evaluated brain tissue oxygen levels before and after picrotoxin injection. Our results showed that neuronal activity typically increased after picrotoxin administration, the BOLD responses to stimulation became negative, and the oxygen response was nearly abolished. Vasoconstriction during the resting baseline was not observed. These results indicate that picrotoxin provoked imbalanced hemodynamics either due to increased neuronal activity, decreased vascular response, or a combination of both.
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Affiliation(s)
- Daniil P. Aksenov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
- Department of Anesthesiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Correspondence:
| | - Limin Li
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Natalya A. Serdyukova
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - David A. Gascoigne
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Evan D. Doubovikov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL 60201, USA
| | - Alexander Drobyshevsky
- Pritzker School of Medicine, University of Chicago, Chicago, IL 60637, USA
- Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL 60201, USA
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6
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Aksenov DP, Gascoigne DA, Duan J, Drobyshevsky A. Function and development of interneurons involved in brain tissue oxygen regulation. Front Mol Neurosci 2022; 15:1069496. [PMID: 36504684 PMCID: PMC9729339 DOI: 10.3389/fnmol.2022.1069496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/09/2022] [Indexed: 11/25/2022] Open
Abstract
The regulation of oxygen in brain tissue is one of the most important fundamental questions in neuroscience and medicine. The brain is a metabolically demanding organ, and its health directly depends on maintaining oxygen concentrations within a relatively narrow range that is both sufficiently high to prevent hypoxia, and low enough to restrict the overproduction of oxygen species. Neurovascular interactions, which are responsible for oxygen delivery, consist of neuronal and glial components. GABAergic interneurons play a particularly important role in neurovascular interactions. The involvement of interneurons extends beyond the perspective of inhibition, which prevents excessive neuronal activity and oxygen consumption, and includes direct modulation of the microvasculature depending upon their sub-type. Namely, nitric oxide synthase-expressing (NOS), vasoactive intestinal peptide-expressing (VIP), and somatostatin-expressing (SST) interneurons have shown modulatory effects on microvessels. VIP interneurons are known to elicit vasodilation, SST interneurons typically cause vasoconstriction, and NOS interneurons have to propensity to induce both effects. Given the importance and heterogeneity of interneurons in regulating local brain tissue oxygen concentrations, we review their differing functions and developmental trajectories. Importantly, VIP and SST interneurons display key developmental milestones in adolescence, while NOS interneurons mature much earlier. The implications of these findings point to different periods of critical development of the interneuron-mediated oxygen regulatory systems. Such that interference with normal maturation processes early in development may effect NOS interneuron neurovascular interactions to a greater degree, while insults later in development may be more targeted toward VIP- and SST-mediated mechanisms of oxygen regulation.
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Affiliation(s)
- Daniil P. Aksenov
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States,Department of Anesthesiology, NorthShore University HealthSystem, Evanston, IL, United States,Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,*Correspondence: Daniil P. Aksenov,
| | - David A. Gascoigne
- Department of Radiology, NorthShore University HealthSystem, Evanston, IL, United States
| | - Jubao Duan
- Center for Psychiatric Genetics, NorthShore University HealthSystem, Evanston, IL, United States,Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, IL, United States
| | - Alexander Drobyshevsky
- Pritzker School of Medicine, University of Chicago, Chicago, IL, United States,Department of Pediatrics, NorthShore University HealthSystem, Evanston, IL, United States
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Shaul D, Grieb B, Lev‐Cohain N, Sosna J, Gomori JM, Katz‐Brull R. Accumulation of 3-aminopropylphosphonate in the ex vivo brain observed by phosphorus-31 nuclear magnetic resonance. NMR IN BIOMEDICINE 2022; 35:e4721. [PMID: 35229366 PMCID: PMC9540894 DOI: 10.1002/nbm.4721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 06/14/2023]
Abstract
3-aminopropylphosphonate (3-APP) is known for its use as an exogenous indicator of extracellular volume and pH in phosphorus-31 nuclear magnetic resonance (31 P NMR) studies. We used 3-APP for estimating the extracellular volume in NMR studies of several ex vivo preparations including retrograde perfused mouse heart (n = 4), mouse liver slices (n = 2), xenograft breast cancer tumors (n = 7, MCF7), and rat brain slices (n = 4). In the former three preparations, the 3-APP signal was stable in lineshape and intensity for hours and the chemical shift of the signal in the presence of the biological sample was the same as in the perfusion medium without the biological sample. However, in studies of brain slices, the 3-APP signal appeared split into two, with an upfield component (0.7 ± 0.1 ppm to the left) increasing with time and showing a wider linewidth (66.7 ± 12.6 vs. 39.1 ± 7.6 Hz, the latter is of the perfusion medium signal). This finding suggests that 3-APP inadvertently accumulated in brain slices, most likely as a membrane bound form. This observation limits the use of 3-APP as an inert biochemical indicator in brain preparations and should be taken into account when using 3-APP in vivo.
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Affiliation(s)
- David Shaul
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
- The Wohl Institute for Translational MedicineJerusalemIsrael
| | - Benjamin Grieb
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
- Department of Psychiatry and Psychotherapie I (Weissenau), ZfP SuedwuerttembergUlm UniversityRavensburgGermany
| | - Naama Lev‐Cohain
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
| | - Jacob Sosna
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
| | - J. Moshe Gomori
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
| | - Rachel Katz‐Brull
- Department of Radiology, Hadassah Medical CenterHebrew University of Jerusalem, The Faculty of MedicineJerusalemIsrael
- The Wohl Institute for Translational MedicineJerusalemIsrael
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8
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Reeson P, Schager B, Van Sprengel M, Brown CE. Behavioral and Neural Activity-Dependent Recanalization of Plugged Capillaries in the Brain of Adult and Aged Mice. Front Cell Neurosci 2022; 16:876746. [PMID: 35722620 PMCID: PMC9204343 DOI: 10.3389/fncel.2022.876746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
The capillaries of the brain, owing to their small diameter and low perfusion pressure, are vulnerable to interruptions in blood flow. These tiny occlusions can have outsized consequences on angioarchitecture and brain function; especially when exacerbated by disease states or accumulate with aging. A distinctive feature of the brain’s microvasculature is the ability for active neurons to recruit local blood flow. The coupling of neural activity to blood flow could play an important role in recanalizing obstructed capillaries. To investigate this idea, we experimentally induced capillary obstructions in mice by injecting fluorescent microspheres and then manipulated neural activity levels though behavioral or pharmacologic approaches. We show that engaging adult and aged mice with 12 h exposure to an enriched environment (group housing, novel objects, exercise wheels) was sufficient to significantly reduce the density of obstructed capillaries throughout the forebrain. In order to more directly manipulate neural activity, we pharmacologically suppressed or increased neuronal activity in the somatosensory cortex. When we suppressed cortical activity, recanalization was impaired given the density of obstructed capillaries was significantly increased. Conversely, increasing cortical activity improved capillary recanalization. Since systemic cardiovascular factors (changes in heart rate, blood pressure) could explain these effects on recanalization, we demonstrate that unilateral manipulations of neural activity through whisker trimming or injection of muscimol, still had significant and hemisphere specific effects on recanalization, even in mice exposed to enrichment where cardiovascular effects would be evident in both hemispheres. In summary, our studies reveal that neural activity bi-directionally regulates the recanalization of obstructed capillaries. Further, we show that stimulating brain activity through behavioral engagement (i.e., environmental enrichment) can promote vascular health throughout the lifespan.
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Affiliation(s)
- Patrick Reeson
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | - Ben Schager
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
| | | | - Craig E. Brown
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada
- Department of Psychiatry, University of British Columbia, Vancouver, BC, Canada
- *Correspondence: Craig E. Brown,
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9
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Stokum JA, Shim B, Huang W, Kane M, Smith JA, Gerzanich V, Simard JM. A large portion of the astrocyte proteome is dedicated to perivascular endfeet, including critical components of the electron transport chain. J Cereb Blood Flow Metab 2021; 41:2546-2560. [PMID: 33818185 PMCID: PMC8504955 DOI: 10.1177/0271678x211004182] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The perivascular astrocyte endfoot is a specialized and diffusion-limited subcellular compartment that fully ensheathes the cerebral vasculature. Despite their ubiquitous presence, a detailed understanding of endfoot physiology remains elusive, in part due to a limited understanding of the proteins that distinguish the endfoot from the greater astrocyte body. Here, we developed a technique to isolate astrocyte endfeet from brain tissue, which was used to study the endfoot proteome in comparison to the astrocyte somata. In our approach, brain microvessels, which retain their endfoot processes, were isolated from mouse brain and dissociated, whereupon endfeet were recovered using an antibody-based column astrocyte isolation kit. Our findings expand the known set of proteins enriched at the endfoot from 10 to 516, which comprised more than 1/5th of the entire detected astrocyte proteome. Numerous critical electron transport chain proteins were expressed only at the endfeet, while enzymes involved in glycogen storage were distributed to the somata, indicating subcellular metabolic compartmentalization. The endfoot proteome also included numerous proteins that, while known to have important contributions to blood-brain barrier function, were not previously known to localize to the endfoot. Our findings highlight the importance of the endfoot and suggest new routes of investigation into endfoot function.
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Affiliation(s)
- Jesse A Stokum
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bosung Shim
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, USA
| | - Maureen Kane
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland, Baltimore, MD, USA
| | - Jesse A Smith
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA
| | - J Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Pathology, University of Maryland School of Medicine, Baltimore, MD, USA.,Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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10
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Baranowski BJ, Allen MD, Nyarko JN, Rector RS, Padilla J, Mousseau DD, Rau CD, Wang Y, Laughlin MH, Emter CA, MacPherson RE, Olver TD. Cerebrovascular insufficiency and amyloidogenic signaling in Ossabaw swine with cardiometabolic heart failure. JCI Insight 2021; 6:143141. [PMID: 34027891 PMCID: PMC8262360 DOI: 10.1172/jci.insight.143141] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 04/14/2021] [Indexed: 12/26/2022] Open
Abstract
Individuals with heart failure (HF) frequently present with comorbidities, including obesity, insulin resistance, hypertension, and dyslipidemia. Many patients with HF experience cardiogenic dementia, yet the pathophysiology of this disease remains poorly understood. Using a swine model of cardiometabolic HF (Western diet+aortic banding; WD-AB), we tested the hypothesis that WD-AB would promote a multidementia phenotype involving cerebrovascular dysfunction alongside evidence of Alzheimer’s disease (AD) pathology. The results provide evidence of cerebrovascular insufficiency coupled with neuroinflammation and amyloidosis in swine with experimental cardiometabolic HF. Although cardiac ejection fraction was normal, indices of arterial compliance and cerebral blood flow were reduced, and cerebrovascular regulation was impaired in the WD-AB group. Cerebrovascular dysfunction occurred concomitantly with increased MAPK signaling and amyloidogenic processing (i.e., increased APP, BACE1, CTF, and Aβ40 in the prefrontal cortex and hippocampus) in the WD-AB group. Transcriptomic profiles of the stellate ganglia revealed the WD-AB group displayed an enrichment of gene networks associated with MAPK/ERK signaling, AD, frontotemporal dementia, and a number of behavioral phenotypes implicated in cognitive impairment. These provide potentially novel evidence from a swine model that cerebrovascular and neuronal pathologies likely both contribute to the dementia profile in a setting of cardiometabolic HF.
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Affiliation(s)
- Bradley J Baranowski
- Department of Health Sciences and.,Centre for Neuroscience, Brock University, St. Catharines, Ontario, Canada
| | - Matti D Allen
- Department of Physical Medicine and Rehabilitation, School of Medicine, Faculty of Health Sciences, Queen's University, Kingston, Ontario, Canada
| | - Jennifer Nk Nyarko
- Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - R Scott Rector
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, USA.,Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, Missouri, USA
| | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri, USA.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri, USA
| | - Darrell D Mousseau
- Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Christoph D Rau
- Department of Genetics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Yibin Wang
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA
| | - M Harold Laughlin
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Craig A Emter
- Department of Biomedical Sciences, University of Missouri, Columbia, Missouri, USA
| | - Rebecca Ek MacPherson
- Department of Health Sciences and.,Centre for Neuroscience, Brock University, St. Catharines, Ontario, Canada
| | - T Dylan Olver
- Department of Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
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11
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Lim HK, You N, Bae S, Kang BM, Shon YM, Kim SG, Suh M. Differential contribution of excitatory and inhibitory neurons in shaping neurovascular coupling in different epileptic neural states. J Cereb Blood Flow Metab 2021; 41:1145-1161. [PMID: 32669018 PMCID: PMC8054729 DOI: 10.1177/0271678x20934071] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Understanding the neurovascular coupling (NVC) underlying hemodynamic changes in epilepsy is crucial to properly interpreting functional brain imaging signals associated with epileptic events. However, how excitatory and inhibitory neurons affect vascular responses in different epileptic states remains unknown. We conducted real-time in vivo measurements of cerebral blood flow (CBF), vessel diameter, and excitatory and inhibitory neuronal calcium signals during recurrent focal seizures. During preictal states, decreases in CBF and arteriole diameter were closely related to decreased γ-band local field potential (LFP) power, which was linked to relatively elevated excitatory and reduced inhibitory neuronal activity levels. Notably, this preictal condition was followed by a strengthened ictal event. In particular, the preictal inhibitory activity level was positively correlated with coherent oscillating activity specific to inhibitory neurons. In contrast, ictal states were characterized by elevated synchrony in excitatory neurons. Given these findings, we suggest that excitatory and inhibitory neurons differentially contribute to shaping the ictal and preictal neural states, respectively. Moreover, the preictal vascular activity, alongside with the γ-band, may reflect the relative levels of excitatory and inhibitory neuronal activity, and upcoming ictal activity. Our findings provide useful insights into how perfusion signals of different epileptic states are related in terms of NVC.
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Affiliation(s)
- Hyun-Kyoung Lim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biological Sciences, Sungkyunkwan University, Suwon, South Korea
| | - Nayeon You
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Sungjun Bae
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Bok-Man Kang
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Young-Min Shon
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea
| | - Minah Suh
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon, South Korea.,Department of Biomedical Engineering, Sungkyunkwan University, Suwon, South Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, South Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon, South Korea
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12
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Cho I, Kim JM, Kim EJ, Kim SY, Kam EH, Cheong E, Suh M, Koo BN. Orthopedic surgery-induced cognitive dysfunction is mediated by CX3CL1/R1 signaling. J Neuroinflammation 2021; 18:93. [PMID: 33858422 PMCID: PMC8048361 DOI: 10.1186/s12974-021-02150-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/05/2021] [Indexed: 12/31/2022] Open
Abstract
Background Postoperative pain is a common phenomenon after surgery and is closely associated with the development of postoperative cognitive dysfunction (POCD). Persistent pain and systemic inflammation caused by surgery have been suggested as key factors for the development of POCD. Fractalkine (CX3CL1) and its receptor, the CX3C chemokine receptor 1 (CX3CR1), are known to play a key role in pain and inflammation signaling pathways. Recent studies have shown that the regulation of CX3CR1/L1 signaling influences the development of various diseases including neuronal diseases. We determined whether CX3CR1/L1 signaling is a putative therapeutic target for POCD in a mouse model. Methods Adult (9–11 weeks) male mice were treated with neutralizing antibody to block CX3CR1/L1 signaling both before and after surgery. Inflammatory and behavioral responses including pain were assessed postoperatively. Also, CX3CR1 mRNA level was assessed. Hippocampal astrocyte activation, Mao B expression, and GABA expression were assessed at 2 days after surgery following neutralizing antibody administration. Results The behavioral response indicated cognitive dysfunction and development of pain in the surgery group compared with the control group. Also, increased levels of pro-inflammatory cytokines and CX3CR1 mRNA were observed in the surgery group. In addition, increased levels of GABA and increased Mao B expression were observed in reactive astrocytes in the surgery group; these responses were attenuated by neutralizing antibody administration. Conclusions Increased CX3CR1 after surgery is both necessary and sufficient to induce cognitive dysfunction. CX3CR1 could be an important target for therapeutic strategies to prevent the development of POCD. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02150-x.
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Affiliation(s)
- Inja Cho
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jeong Min Kim
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Eun Jung Kim
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - So Yeon Kim
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Eun Hee Kam
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Eunji Cheong
- Department of Biotechnology, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Minah Suh
- Department of Biomedical Engineering, Sungkyunkwan University, 2066, Seobu-ro, Jangan-gu, Suwon-si, Gyeong gi-do, 16419, Republic of Korea.,Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Sungkyunkwan University, Suwon, Korea.,Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon, 16419, South Korea.,Samsung Advanced Institute for Health Sciences & Technology (SAIHST), Sungkyunkwan University, Suwon, 16419, South Korea
| | - Bon-Nyeo Koo
- Department of Anesthesiology and Pain Medicine, Yonsei University College of Medicine, 50-1, Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea. .,Anesthesia and Pain Research Institute, Yonsei University College of Medicine, Seoul, Korea.
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13
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Balan PF, Gerits A, Zhu Q, Kolster H, Orban GA, Wardak C, Vanduffel W. Fast Compensatory Functional Network Changes Caused by Reversible Inactivation of Monkey Parietal Cortex. Cereb Cortex 2020; 29:2588-2606. [PMID: 29901747 DOI: 10.1093/cercor/bhy128] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 04/30/2018] [Accepted: 05/09/2018] [Indexed: 11/13/2022] Open
Abstract
The brain has a remarkable capacity to recover after lesions. However, little is known about compensatory neural adaptations at the systems level. We addressed this question by investigating behavioral and (correlated) functional changes throughout the cortex that are induced by focal, reversible inactivations. Specifically, monkeys performed a demanding covert spatial attention task while the lateral intraparietal area (LIP) was inactivated with muscimol and whole-brain fMRI activity was recorded. The inactivation caused LIP-specific decreases in task-related fMRI activity. In addition, these local effects triggered large-scale network changes. Unlike most studies in which animals were mainly passive relative to the stimuli, we observed heterogeneous effects with more profound muscimol-induced increases of task-related fMRI activity in areas connected to LIP, especially FEF. Furthermore, in areas such as FEF and V4, muscimol-induced changes in fMRI activity correlated with changes in behavioral performance. Notably, the activity changes in remote areas did not correlate with the decreased activity at the site of the inactivation, suggesting that such changes arise via neuronal mechanisms lying in the intact portion of the functional task network, with FEF a likely key player. The excitation-inhibition dynamics unmasking existing excitatory connections across the functional network might initiate these rapid adaptive changes.
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Affiliation(s)
- Puiu F Balan
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Annelies Gerits
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium
| | - Qi Zhu
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium
| | - Hauke Kolster
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium
| | - Guy A Orban
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium.,Department of Medicine and Surgery, University of Parma, via Volturno, 39E Parma, Italy
| | - Claire Wardak
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium
| | - Wim Vanduffel
- Laboratorium voor Neuro- en Psychofysiologie, KU Leuven Medical School, Campus Gasthuisberg, Leuven, Belgium.,Leuven Brain Institute, Leuven, Belgium.,Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Harvard Medical School, Charlestown, MA, USA
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14
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Neurovascular Coupling under Chronic Stress Is Modified by Altered GABAergic Interneuron Activity. J Neurosci 2019; 39:10081-10095. [PMID: 31672788 PMCID: PMC6978951 DOI: 10.1523/jneurosci.1357-19.2019] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/10/2019] [Accepted: 10/15/2019] [Indexed: 12/15/2022] Open
Abstract
Neurovascular coupling (NVC), the interaction between neural activity and vascular response, ensures normal brain function by maintaining brain homeostasis. We previously reported altered cerebrovascular responses during functional hyperemia in chronically stressed animals. However, the underlying neuronal-level changes associated with those hemodynamic changes remained unclear. Here, using in vivo and ex vivo experiments, we investigate the neuronal origins of altered NVC dynamics under chronic stress conditions in adult male mice. Stimulus-evoked hemodynamic and neural responses, especially beta and gamma-band local field potential activity, were significantly lower in chronically stressed animals, and the NVC relationship, itself, had changed. Further, using acute brain slices, we discovered that the underlying cause of this change was dysfunction of neuronal nitric oxide synthase (nNOS)-mediated vascular responses. Using FISH to check the mRNA expression of several GABAergic subtypes, we confirmed that only nNOS mRNA was significantly decreased in chronically stressed mice. Ultimately, chronic stress impairs NVC by diminishing nNOS-mediated vasodilation responses to local neural activity. Overall, these findings provide useful information in understanding NVC dynamics in the healthy brain. More importantly, this study reveals that impaired nNOS-mediated NVC function may be a contributory factor in the progression of stress-related diseases. SIGNIFICANCE STATEMENT The correlation between neuronal activity and cerebral vascular dynamics is defined as neurovascular coupling (NVC), which plays an important role for meeting the metabolic demands of the brain. However, the impact of chronic stress, which is a contributory factor of many cerebrovascular diseases, on NVC is poorly understood. We therefore investigated the effects of chronic stress on impaired neurovascular response to sensory stimulation and their underlying mechanisms. Multimodal approaches, from in vivo hemodynamic imaging and electrophysiology to ex vivo vascular imaging with pharmacological treatment, patch-clamp recording, FISH, and immunohistochemistry revealed that chronic stress-induced dysfunction of nNOS-expressing interneurons contributes to NVC impairment. These findings will provide useful information to understand the role of nNOS interneurons in NVC in normal and pathological conditions.
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15
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Schneider J, Berndt N, Papageorgiou IE, Maurer J, Bulik S, Both M, Draguhn A, Holzhütter HG, Kann O. Local oxygen homeostasis during various neuronal network activity states in the mouse hippocampus. J Cereb Blood Flow Metab 2019; 39:859-873. [PMID: 29099662 PMCID: PMC6501513 DOI: 10.1177/0271678x17740091] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/02/2017] [Indexed: 12/14/2022]
Abstract
Cortical information processing comprises various activity states emerging from timed synaptic excitation and inhibition. However, the underlying energy metabolism is widely unknown. We determined the cerebral metabolic rate of oxygen (CMRO2) along a tissue depth of <0.3 mm in the hippocampal CA3 region during various network activities, including gamma oscillations and sharp wave-ripples that occur during wakefulness and sleep. These physiological states associate with sensory perception and memory formation, and critically depend on perisomatic GABA inhibition. Moreover, we modelled vascular oxygen delivery based on quantitative microvasculature analysis. (1) Local CMRO2 was highest during gamma oscillations (3.4 mM/min), medium during sharp wave-ripples, asynchronous activity and isoflurane application (2.0-1.6 mM/min), and lowest during tetrodotoxin application (1.4 mM/min). (2) Energy expenditure of axonal and synaptic signaling accounted for >50% during gamma oscillations. (3) CMRO2 positively correlated with number and synchronisation of activated synapses, and neural multi-unit activity. (4) The median capillary distance was 44 µm. (5) The vascular oxygen partial pressure of 33 mmHg was needed to sustain oxidative phosphorylation during gamma oscillations. We conclude that gamma oscillations featuring high energetics require a hemodynamic response to match oxygen consumption of respiring mitochondria, and that perisomatic inhibition significantly contributes to the brain energy budget.
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Affiliation(s)
- Justus Schneider
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Nikolaus Berndt
- Computational Systems Biochemistry, Institute of Biochemistry, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Ismini E Papageorgiou
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Jana Maurer
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Sascha Bulik
- Computational Systems Biochemistry, Institute of Biochemistry, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Martin Both
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Andreas Draguhn
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
| | - Hermann-Georg Holzhütter
- Computational Systems Biochemistry, Institute of Biochemistry, Charité–Universitätsmedizin Berlin, Berlin, Germany
| | - Oliver Kann
- Institute of Physiology and Pathophysiology, and Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
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16
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Todd N, Zhang Y, Power C, Becerra L, Borsook D, Livingstone M, McDannold N. Modulation of brain function by targeted delivery of GABA through the disrupted blood-brain barrier. Neuroimage 2019; 189:267-275. [PMID: 30659957 PMCID: PMC6422703 DOI: 10.1016/j.neuroimage.2019.01.037] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 11/29/2018] [Accepted: 01/14/2019] [Indexed: 12/11/2022] Open
Abstract
The technology of transcranial focused ultrasound (FUS) enables a novel approach to neuromodulation, a tool for selective manipulation of brain function to be used in neurobiology research and with potential applications in clinical treatment. The method uses transcranial focused ultrasound to non-invasively open the blood-brain barrier (BBB) in a localized region such that a systemically injected neurotransmitter chemical can be delivered to the targeted brain site. The approach modulates the chemical signaling that occurs in and between neurons, making it complimentary to most other neuromodulation techniques that affect the electrical properties of neuronal activity. Here, we report delivering the inhibitory neurotransmitter GABA to the right somatosensory cortex of the rat brain during bilateral hind paw electrical stimulation and measure the inhibition of activation using functional MRI (fMRI). In a 2 × 2 factorial design, we evaluated conditions of BBB Closed vs BBB Open and No GABA vs GABA. Results from fMRI measurements of the blood oxygen level-dependent (BOLD) signal show: 1) intravenous GABA injection without FUS-mediated BBB opening does not have an effect on the BOLD response; 2) FUS-mediated BBB opening alone significantly alters the BOLD signal response to the stimulus, both in amplitude and shape of the time course; 3) the combination of FUS-mediated BBB opening and GABA injection further reduces the peak amplitude and spatial extent of the BOLD signal response to the stimulus. The data support the thesis that FUS-mediated opening of the BBB can be used to achieve non-invasive delivery of neuroactive substances for targeted manipulation of brain function.
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Affiliation(s)
- Nick Todd
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA.
| | - Yongzhi Zhang
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Chanikarn Power
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Lino Becerra
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - David Borsook
- Center for Pain and the Brain, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA; Department of Anesthesia, Perioperative, and Pain Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | | | - Nathan McDannold
- Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
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17
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How reliable is cerebral blood flow to map changes in neuronal activity? Auton Neurosci 2019; 217:71-79. [PMID: 30744905 DOI: 10.1016/j.autneu.2019.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/17/2018] [Accepted: 01/27/2019] [Indexed: 02/06/2023]
Abstract
Neuroimaging techniques, such as functional MRI, map brain activity through hemodynamic-based signals, and are invaluable diagnostic tools in several neurological disorders such as stroke and dementia. Hemodynamic signals are normally precisely related to the underlying neuronal activity through neurovascular coupling mechanisms that ensure the supply of blood, glucose and oxygen to neurons at work. The knowledge of neurovascular coupling has greatly advanced over the last 30 years, it involves multifaceted interactions between excitatory and inhibitory neurons, astrocytes, and the microvessels. While the tight relationship between blood flow and neuronal activity forms a fundamental brain function, whether neurovascular coupling mechanisms are reliable across physiological and pathological conditions has been questioned. In this review, we interrogate the relationship between blood flow and neuronal activity during activation of different brain pathways: a sensory stimulation driven by glutamate, and stimulation of neuromodulatory pathways driven by acetylcholine or noradrenaline, and we compare the underlying neurovascular coupling mechanisms. We further question if neurovascular coupling mechanisms are affected by changing brain states, as seen in behavioral conditions of sleep, wakefulness, attention and in pathological conditions. Finally, we provide a short overview of how alterations of the brain vasculature could compromise the reliability of neurovascular coupling. Overall, while neurovascular coupling requires activation of common signalling pathways, alternate unique cascades exist depending on the activated pathways. Further studies are needed to fully elucidate the alterations in neurovascular coupling across brain states and pathological conditions.
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18
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Abstract
To explore alterations in γ-aminobutyric acid (GABA) levels in response to levetiracetam (LEV) treatment in patients with migraine. Patients with migraine (N=14) were treated with LEV for 12 weeks. The levels of GABA+ in the anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC) and the posterior cingulate cortex (PCC) were examined by proton magnetic resonance spectroscopy before (baseline) and after treatment. LEV showed good efficacy in the reduction of headache frequency and intensity in patients with migraine. Among the 14 patients, good-quality spectral data of GABA+ in the PCC region were obtained in 11 patients. There was a significant decrease in GABA+ levels in the PCC region after LEV treatment. ACC/mPFC GABA+ was assessed by proton magnetic resonance spectroscopy in eight patients with migraine. LEV had no significant effect on GABA+ levels in the ACC/mPFC region. The decreased GABA+ levels after LEV treatment in patients with migraine suggest that GABA is a migraine biomarker.
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19
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Kalinichenko SG, Pushchin II. The modular architecture and neurochemical patterns in the cerebellar cortex. J Chem Neuroanat 2018; 92:16-24. [PMID: 29753860 DOI: 10.1016/j.jchemneu.2018.05.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 05/08/2018] [Accepted: 05/09/2018] [Indexed: 10/24/2022]
Abstract
The review deals with topical issues of the neuronal arrangement underlying basic cerebellar functions. The cerebellum and its auxiliary structures contain several hundreds of modules (so called "microzones"). Each module receives the corticopetal input specific for the lobule it belongs to and forms the topographic projection. The precision of the major input-output signal flow in the cerebellar cortex is provided by a pronounced stratification of its synaptic zones of a various origin and regular topography of its afferent connections, interneurons, and efferent neurons. There is a nice match between the anatomical and functional coordinates of the modules, whose spatial boundaries are determined by the spread of afferent excitation and local interneuron connections. The dynamic characteristics of the modules are analyzed by the example of the formation of the nitrergic neuron ensembles and cerebellar projections of corticopetal fibers. The authors discuss the cerebellar blood flow and its relation to the activity of NO/GABAergic Lugaro cells and other interneurons in the cerebellar cortex. A generalized scheme of intra- and intermodular communication is proposed.
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Affiliation(s)
- Sergei G Kalinichenko
- Department of Histology, Cytology and Embryology, Pacific State Medical University, Vladivostok 690950, Russia
| | - Igor I Pushchin
- Laboratory of Physiology, A.V. Zhirmunsky Institute of Marine Biology, National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 17 Palchevskogo Street, Vladivostok, 690041, Russia.
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20
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Montoro CI, Duschek S, Reyes del Paso GA. Variability in cerebral blood flow velocity at rest and during mental stress in healthy individuals: Associations with cardiovascular parameters and cognitive performance. Biol Psychol 2018; 135:149-158. [DOI: 10.1016/j.biopsycho.2018.04.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Revised: 01/16/2018] [Accepted: 04/11/2018] [Indexed: 10/17/2022]
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21
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Functional networks and network perturbations in rodents. Neuroimage 2017; 163:419-436. [DOI: 10.1016/j.neuroimage.2017.09.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 09/15/2017] [Accepted: 09/19/2017] [Indexed: 11/16/2022] Open
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22
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Stefanits H, Milenkovic I, Mahr N, Pataraia E, Hainfellner JA, Kovacs GG, Sieghart W, Yilmazer-Hanke D, Czech T. GABAAreceptor subunits in the human amygdala and hippocampus: Immunohistochemical distribution of 7 subunits. J Comp Neurol 2017; 526:324-348. [DOI: 10.1002/cne.24337] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 09/12/2017] [Accepted: 09/19/2017] [Indexed: 12/18/2022]
Affiliation(s)
- Harald Stefanits
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
- Institute of Neurology, Medical University of Vienna; Vienna Austria
| | - Ivan Milenkovic
- Department of Clinical Neurology; Medical University of Vienna; Vienna Austria
| | - Nina Mahr
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
| | - Ekaterina Pataraia
- Department of Clinical Neurology; Medical University of Vienna; Vienna Austria
| | | | - Gabor G. Kovacs
- Institute of Neurology, Medical University of Vienna; Vienna Austria
| | - Werner Sieghart
- Center for Brain Research, Department of Molecular Neurosciences; Medical University of Vienna; Vienna Austria
| | - Deniz Yilmazer-Hanke
- Clinical Neuroanatomy, Neurology Department, Medical Faculty; Ulm University; Ulm Germany
| | - Thomas Czech
- Department of Neurosurgery; Medical University of Vienna; Vienna Austria
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23
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Abstract
Cortical networks are composed of glutamatergic excitatory projection neurons and local GABAergic inhibitory interneurons that gate signal flow and sculpt network dynamics. Although they represent a minority of the total neocortical neuronal population, GABAergic interneurons are highly heterogeneous, forming functional classes based on their morphological, electrophysiological, and molecular features, as well as connectivity and in vivo patterns of activity. Here we review our current understanding of neocortical interneuron diversity and the properties that distinguish cell types. We then discuss how the involvement of multiple cell types, each with a specific set of cellular properties, plays a crucial role in diversifying and increasing the computational power of a relatively small number of simple circuit motifs forming cortical networks. We illustrate how recent advances in the field have shed light onto the mechanisms by which GABAergic inhibition contributes to network operations.
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24
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Love S, Miners J. Cerebral Hypoperfusion and the Energy Deficit in Alzheimer's Disease. Brain Pathol 2016; 26:607-17. [PMID: 27327656 PMCID: PMC8028913 DOI: 10.1111/bpa.12401] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 06/21/2016] [Accepted: 05/25/2016] [Indexed: 12/19/2022] Open
Abstract
There is a perfusion deficit in Alzheimer's disease (AD), commencing in the precuneus and spreading to other parts of the cerebral cortex. The deficit anticipates the development of dementia, contributes to brain damage, and is caused by both functional and structural abnormalities of the cerebral vasculature. Most of the abnormalities are probably secondary to the accumulation of Aβ but the consequent hypoperfusion may, in turn, increase Aβ production. In the early stages of disease, abnormalities that cause vasoconstriction predominate. These include cholinergic vascular denervation, inhibition of endothelial nitric oxide synthase, increased production of endothelin-1 production and possibly also of angiotensin II. Patients with AD also have an increased prevalence of structural disease of cerebral microvessels, particularly CAA and capillary damage, and particularly in the later stages of disease these are likely to make an important contribution to the cerebral hypoperfusion. The metabolic abnormalities that cause early vascular dysfunction offer several targets for therapeutic intervention. However, for intervention to be effective it probably needs to be early. Prolonged cerebral hypoperfusion may induce compensatory circulatory changes that are themselves damaging, including hypertension and small vessel disease. This has implications for the use of antihypertensive drugs once there is accumulation of Aβ within the brain.
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Affiliation(s)
- Seth Love
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
| | - J.Scott Miners
- Dementia Research Group, Institute of Clinical Neurosciences, School of Clinical SciencesUniversity of BristolBristolUnited Kingom
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25
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Buzhdygan T, Lisinicchia J, Patel V, Johnson K, Neugebauer V, Paessler S, Jennings K, Gelman B. Neuropsychological, Neurovirological and Neuroimmune Aspects of Abnormal GABAergic Transmission in HIV Infection. J Neuroimmune Pharmacol 2016; 11:279-93. [PMID: 26829944 PMCID: PMC4848342 DOI: 10.1007/s11481-016-9652-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 01/18/2016] [Indexed: 01/19/2023]
Abstract
The prevalence of HIV-associated neurocognitive disorders (HAND) remains high in patients with effective suppression of virus replication by combination antiretroviral therapy (cART). Several neurotransmitter systems were reported to be abnormal in HIV-infected patients, including the inhibitory GABAergic system, which mediates fine-tuning of neuronal processing and plays an essential role in cognitive functioning. To elucidate the role of abnormal GABAergic transmission in HAND, the expression of GABAergic markers was measured in 449 human brain specimens from HIV-infected patients with and without HAND. Using real-time polymerase chain reaction, immunoblotting and immunohistochemistry we found that the GABAergic markers were significantly decreased in most sectors of cerebral neocortex, the neostriatum, and the cerebellum of HIV-infected subjects. Low GABAergic expression in frontal neocortex was correlated significantly with high expression of endothelial cell markers, dopamine receptor type 2 (DRD2L), and preproenkephalin (PENK) mRNAs, and with worse performance on tasks of verbal fluency. Significant associations were not found between low GABAergic mRNAs and HIV-1 RNA concentration in the brain, the history of cART, or HIV encephalitis. Pathological evidence of neurodegeneration of the affected GABAergic neurons was not present. We conclude that abnormally low expression of GABAergic markers is prevalent in HIV-1 infected patients. Interrelationships with other neurotransmitter systems including dopaminergic transmission and with endothelial cell markers lend added support to suggestions that synaptic plasticity and cerebrovascular anomalies are involved with HAND in virally suppressed patients.
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Affiliation(s)
- Tetyana Buzhdygan
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Joshua Lisinicchia
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Vipulkumar Patel
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Kenneth Johnson
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Volker Neugebauer
- Department of Pharmacology and Neuroscience, School of Medicine, Texas Tech University Health Sciences Center, 3601 4th Street, 79430-6592, Lubbock, TX, USA
| | - Slobodan Paessler
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Kristofer Jennings
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA
| | - Benjamin Gelman
- Department of Pathology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA.
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, 301 University Blvd, 77555-0609, Galveston, TX, USA.
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Saillet S, Quilichini PP, Ghestem A, Giusiano B, Ivanov AI, Hitziger S, Vanzetta I, Bernard C, Bénar CG. Interneurons contribute to the hemodynamic/metabolic response to epileptiform discharges. J Neurophysiol 2015; 115:1157-69. [PMID: 26745250 DOI: 10.1152/jn.00994.2014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2014] [Accepted: 12/21/2015] [Indexed: 01/28/2023] Open
Abstract
Interpretation of hemodynamic responses in epilepsy is hampered by an incomplete understanding of the underlying neurovascular coupling, especially the contributions of excitation and inhibition. We made simultaneous multimodal recordings of local field potentials (LFPs), firing of individual neurons, blood flow, and oxygen level in the somatosensory cortex of anesthetized rats. Epileptiform discharges induced by bicuculline injections were used to trigger large local events. LFP and blood flow were robustly coupled, as were LFP and tissue oxygen. In a parametric linear model, LFP and the baseline activities of cerebral blood flow and tissue partial oxygen tension contributed significantly to blood flow and oxygen responses. In an analysis of recordings from 402 neurons, blood flow/tissue oxygen correlated with the discharge of putative interneurons but not of principal cells. Our results show that interneuron activity is important in the vascular and metabolic responses during epileptiform discharges.
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Affiliation(s)
- Sandrine Saillet
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Pascale P Quilichini
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Antoine Ghestem
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Bernard Giusiano
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France; APHM, Timone Hospital, Division of Public Health, Marseille, France
| | - Anton I Ivanov
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | | | - Ivo Vanzetta
- Aix-Marseille Université, CNRS, INT UMR 7289, Marseille, France
| | - Christophe Bernard
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France
| | - Christian-G Bénar
- INSERM, UMR 1106, Marseille, France; Aix-Marseille Université, Institut de Neurosciences des Systèmes, Marseille, France;
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Optogenetic stimulation of GABA neurons can decrease local neuronal activity while increasing cortical blood flow. J Cereb Blood Flow Metab 2015; 35:1579-86. [PMID: 26082013 PMCID: PMC4640302 DOI: 10.1038/jcbfm.2015.140] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 05/04/2015] [Accepted: 05/20/2015] [Indexed: 12/27/2022]
Abstract
We investigated the link between direct activation of inhibitory neurons, local neuronal activity, and hemodynamics. Direct optogenetic cortical stimulation in the sensorimotor cortex of transgenic mice expressing Channelrhodopsin-2 in GABAergic neurons (VGAT-ChR2) greatly attenuated spontaneous cortical spikes, but was sufficient to increase blood flow as measured with laser speckle contrast imaging. To determine whether the observed optogenetically evoked gamma aminobutyric acid (GABA)-neuron hemodynamic responses were dependent on ionotropic glutamatergic or GABAergic synaptic mechanisms, we paired optogenetic stimulation with application of antagonists to the cortex. Incubation of glutamatergic antagonists directly on the cortex (NBQX and MK-801) blocked cortical sensory evoked responses (as measured with electroencephalography and intrinsic optical signal imaging), but did not significantly attenuate optogenetically evoked hemodynamic responses. Significant light-evoked hemodynamic responses were still present after the addition of picrotoxin (GABA-A receptor antagonist) in the presence of the glutamatergic synaptic blockade. This activation of cortical inhibitory interneurons can mediate large changes in blood flow in a manner that is by and large not dependent on ionotropic glutamatergic or GABAergic synaptic transmission. This supports the hypothesis that activation of inhibitory neurons can increase local cerebral blood flow in a manner that is not entirely dependent on levels of net ongoing neuronal activity.
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Highly energized inhibitory interneurons are a central element for information processing in cortical networks. J Cereb Blood Flow Metab 2014; 34:1270-82. [PMID: 24896567 PMCID: PMC4126088 DOI: 10.1038/jcbfm.2014.104] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/09/2014] [Accepted: 05/21/2014] [Indexed: 01/09/2023]
Abstract
Gamma oscillations (∼30 to 100 Hz) provide a fundamental mechanism of information processing during sensory perception, motor behavior, and memory formation by coordination of neuronal activity in networks of the hippocampus and neocortex. We review the cellular mechanisms of gamma oscillations about the underlying neuroenergetics, i.e., high oxygen consumption rate and exquisite sensitivity to metabolic stress during hypoxia or poisoning of mitochondrial oxidative phosphorylation. Gamma oscillations emerge from the precise synaptic interactions of excitatory pyramidal cells and inhibitory GABAergic interneurons. In particular, specialized interneurons such as parvalbumin-positive basket cells generate action potentials at high frequency ('fast-spiking') and synchronize the activity of numerous pyramidal cells by rhythmic inhibition ('clockwork'). As prerequisites, fast-spiking interneurons have unique electrophysiological properties and particularly high energy utilization, which is reflected in the ultrastructure by enrichment with mitochondria and cytochrome c oxidase, most likely needed for extensive membrane ion transport and γ-aminobutyric acid metabolism. This supports the hypothesis that highly energized fast-spiking interneurons are a central element for cortical information processing and may be critical for cognitive decline when energy supply becomes limited ('interneuron energy hypothesis'). As a clinical perspective, we discuss the functional consequences of metabolic and oxidative stress in fast-spiking interneurons in aging, ischemia, Alzheimer's disease, and schizophrenia.
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Cauli B, Zhou X, Tricoire L, Toussay X, Staiger JF. Revisiting enigmatic cortical calretinin-expressing interneurons. Front Neuroanat 2014; 8:52. [PMID: 25009470 PMCID: PMC4067953 DOI: 10.3389/fnana.2014.00052] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 06/05/2014] [Indexed: 12/18/2022] Open
Abstract
Cortical calretinin (CR)-expressing interneurons represent a heterogeneous subpopulation of about 10-30% of GABAergic interneurons, which altogether total ca. 12-20% of all cortical neurons. In the rodent neocortex, CR cells display different somatodendritic morphologies ranging from bipolar to multipolar but the bipolar cells and their variations dominate. They are also diverse at the molecular level as they were shown to express numerous neuropeptides in different combinations including vasoactive intestinal polypeptide (VIP), cholecystokinin (CCK), neurokinin B (NKB) corticotrophin releasing factor (CRF), enkephalin (Enk) but also neuropeptide Y (NPY) and somatostatin (SOM) to a lesser extent. CR-expressing interneurons exhibit different firing behaviors such as adapting, bursting or irregular. They mainly originate from the caudal ganglionic eminence (CGE) but a subpopulation also derives from the dorsal part of the medial ganglionic eminence (MGE). Cortical GABAergic CR-expressing interneurons can be divided in two main populations: VIP-bipolar interneurons deriving from the CGE and SOM-Martinotti-like interneurons originating in the dorsal MGE. Although bipolar cells account for the majority of CR-expressing interneurons, the roles they play in cortical neuronal circuits and in the more general metabolic physiology of the brain remained elusive and enigmatic. The aim of this review is, firstly, to provide a comprehensive view of the morphological, molecular and electrophysiological features defining this cell type. We will, secondly, also summarize what is known about their place in the cortical circuit, their modulation by subcortical afferents and the functional roles they might play in neuronal processing and energy metabolism.
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Affiliation(s)
- Bruno Cauli
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Xiaojuan Zhou
- Institute for Neuroanatomy, UMG, Georg-August-University Göttingen Göttingen, Germany
| | - Ludovic Tricoire
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Xavier Toussay
- Sorbonne Universités, UPMC University Paris 06, UM CR18, Neuroscience Paris Seine Paris, France ; Centre National de la Recherche Scientifique, UMR 8246, Neuroscience Paris Seine Paris, France ; Institut National de la Santé et de la Recherche Médicale, UMR-S 1130, Neuroscience Paris Seine Paris, France
| | - Jochen F Staiger
- Institute for Neuroanatomy, UMG, Georg-August-University Göttingen Göttingen, Germany
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Jessen SB, Brazhe A, Lind BL, Mathiesen C, Thomsen K, Jensen K, Lauritzen M. GABAA Receptor-Mediated Bidirectional Control of Synaptic Activity, Intracellular Ca2+, Cerebral Blood Flow, and Oxygen Consumption in Mouse Somatosensory Cortex In Vivo. Cereb Cortex 2014; 25:2594-609. [PMID: 24692513 DOI: 10.1093/cercor/bhu058] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Neural activity regulates local increases in cerebral blood flow (ΔCBF) and the cortical metabolic rate of oxygen (ΔCMRO2) that constitutes the basis of BOLD functional neuroimaging signals. Glutamate signaling plays a key role in brain vascular and metabolic control; however, the modulatory effect of GABA is incompletely understood. Here we performed in vivo studies in mice to investigate how THIP (which tonically activates extrasynaptic GABAARs) and Zolpidem (a positive allosteric modulator of synaptic GABAARs) impact stimulation-induced ΔCBF, ΔCMRO2, local field potentials (LFPs), and fluorescent cytosolic Ca(2+) transients in neurons and astrocytes. Low concentrations of THIP increased ΔCBF and ΔCMRO2 at low stimulation frequencies. These responses were coupled to increased synaptic activity as indicated by LFP responses, and to Ca(2+) activities in neurons and astrocytes. Intermediate and high concentrations of THIP suppressed ΔCBF and ΔCMRO2 at high stimulation frequencies. Zolpidem had similar but less-pronounced effects, with similar dependence on drug concentration and stimulation frequency. Our present findings suggest that slight increases in both synaptic and extrasynaptic GABAAR activity might selectively gate and amplify transient low-frequency somatosensory inputs, filter out high-frequency inputs, and enhance vascular and metabolic responses that are likely to be reflected in BOLD functional neuroimaging signals.
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Affiliation(s)
- Sanne Barsballe Jessen
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark Center for Healthy Aging, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Alexey Brazhe
- Biological Faculty Moscow State University, 119234 Moscow, Russia
| | - Barbara Lykke Lind
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Claus Mathiesen
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark Center for Healthy Aging, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Kirsten Thomsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Kimmo Jensen
- Synaptic Physiology Laboratory, Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Martin Lauritzen
- Department of Neuroscience and Pharmacology, University of Copenhagen, 2200 Copenhagen N, Denmark Center for Healthy Aging, University of Copenhagen, 2200 Copenhagen N, Denmark Department of Clinical Neurophysiology, Glostrup Hospital, 2600 Glostrup, Denmark
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31
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Donahue MJ, Rane S, Hussey E, Mason E, Pradhan S, Waddell KW, Ally BA. γ-Aminobutyric acid (GABA) concentration inversely correlates with basal perfusion in human occipital lobe. J Cereb Blood Flow Metab 2014; 34:532-41. [PMID: 24398941 PMCID: PMC3948135 DOI: 10.1038/jcbfm.2013.231] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Revised: 11/14/2013] [Accepted: 12/03/2013] [Indexed: 01/03/2023]
Abstract
Commonly used neuroimaging approaches in humans exploit hemodynamic or metabolic indicators of brain function. However, fundamental gaps remain in our ability to relate such hemo-metabolic reactivity to neurotransmission, with recent reports providing paradoxical information regarding the relationship among basal perfusion, functional imaging contrast, and neurotransmission in awake humans. Here, sequential magnetic resonance spectroscopy (MRS) measurements of the primary inhibitory neurotransmitter, γ-aminobutyric acid (GABA+macromolecules normalized by the complex N-acetyl aspartate-N-acetyl aspartyl glutamic acid: [GABA(+)]/[NAA-NAAG]), and magnetic resonance imaging (MRI) measurements of perfusion, fractional gray-matter volume, and arterial arrival time (AAT) are recorded in human visual cortex from a controlled cohort of young adult male volunteers with neurocognitive battery-confirmed comparable cognitive capacity (3 T; n=16; age=23±3 years). Regression analyses reveal an inverse correlation between [GABA(+)]/[NAA-NAAG] and perfusion (R=-0.46; P=0.037), yet no relationship between AAT and [GABA(+)]/[NAA-NAAG] (R=-0.12; P=0.33). Perfusion measurements that do not control for AAT variations reveal reduced correlations between [GABA(+)]/[NAA-NAAG] and perfusion (R=-0.13; P=0.32). These findings largely reconcile contradictory reports between perfusion and inhibitory tone, and underscore the physiologic origins of the growing literature relating functional imaging signals, hemodynamics, and neurotransmission.
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Affiliation(s)
- Manus J Donahue
- 1] Department of Radiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [2] Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [3] Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [4] Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee, USA
| | - Swati Rane
- Department of Radiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Erin Hussey
- Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Emily Mason
- 1] Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [2] Department of Neuroscience, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Subechhya Pradhan
- Department of Radiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Kevin W Waddell
- Department of Radiology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Brandon A Ally
- 1] Department of Psychiatry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA [2] Department of Neurology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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32
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Dunn KM, Nelson MT. Neurovascular signaling in the brain and the pathological consequences of hypertension. Am J Physiol Heart Circ Physiol 2013; 306:H1-14. [PMID: 24163077 DOI: 10.1152/ajpheart.00364.2013] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The execution and maintenance of all brain functions are dependent on a continuous flow of blood to meet the metabolic needs of the tissue. To ensure the delivery of resources required for neural processing and the maintenance of neural homeostasis, the cerebral vasculature is elaborately and extensively regulated by signaling from neurons, glia, interneurons, and perivascular nerves. Hypertension is associated with impaired neurovascular regulation of the cerebral circulation and culminates in neurodegeneration and cognitive dysfunction. Here, we review the physiological processes of neurovascular signaling in the brain and discuss mechanisms of hypertensive neurovascular dysfunction.
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Affiliation(s)
- Kathryn M Dunn
- Department of Pharmacology, University of Vermont College of Medicine, Burlington, Vermont; and
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33
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Goense J, Merkle H, Logothetis NK. High-resolution fMRI reveals laminar differences in neurovascular coupling between positive and negative BOLD responses. Neuron 2013; 76:629-39. [PMID: 23141073 DOI: 10.1016/j.neuron.2012.09.019] [Citation(s) in RCA: 189] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2012] [Indexed: 11/29/2022]
Abstract
The six cortical layers have distinct anatomical and physiological properties, like different energy use and different feedforward and feedback connectivity. It is not known if and how layer-specific neural processes are reflected in the fMRI signal. To address this question we used high-resolution fMRI to measure BOLD, CBV, and CBF responses to stimuli that elicit positive and negative BOLD signals in macaque primary visual cortex. We found that regions with positive BOLD responses had parallel increases in CBV and CBF, whereas areas with negative BOLD responses showed a decrease in CBF but an increase in CBV. For positive BOLD responses, CBF and CBV increased in the center of the cortex, but for negative BOLD responses, CBF decreased superficially while CBV increased in the center. Our findings suggest different mechanisms for neurovascular coupling for BOLD increases and decreases, as well as laminar differences in neurovascular coupling.
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Affiliation(s)
- Jozien Goense
- Department of Physiology of Cognitive Processes, Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany.
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Duchemin S, Boily M, Sadekova N, Girouard H. The complex contribution of NOS interneurons in the physiology of cerebrovascular regulation. Front Neural Circuits 2012; 6:51. [PMID: 22907993 PMCID: PMC3414732 DOI: 10.3389/fncir.2012.00051] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Accepted: 07/19/2012] [Indexed: 12/23/2022] Open
Abstract
Following the discovery of the vasorelaxant properties of nitric oxide (NO) by Furchgott and Ignarro, the finding by Bredt and coll. of a constitutively expressed NO synthase in neurons (nNOS) led to the presumption that neuronal NO may control cerebrovascular functions. Consequently, numerous studies have sought to determine whether neuraly-derived NO is involved in the regulation of cerebral blood flow (CBF). Anatomically, axons, dendrites, or somata of NO neurons have been found to contact the basement membrane of blood vessels or perivascular astrocytes in all segments of the cortical microcirculation. Functionally, various experimental approaches support a role of neuronal NO in the maintenance of resting CBF as well as in the vascular response to neuronal activity. Since decades, it has been assumed that neuronal NO simply diffuses to the local blood vessels and produce vasodilation through a cGMP-PKG dependent mechanism. However, NO is not the sole mediator of vasodilation in the cerebral microcirculation and is known to interact with a myriad of signaling pathways also involved in vascular control. In addition, cerebrovascular regulation is the result of a complex orchestration between all components of the neurovascular unit (i.e., neuronal, glial, and vascular cells) also known to produce NO. In this review article, the role of NO interneuron in the regulation of cortical microcirculation will be discussed in the context of the neurovascular unit.
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Affiliation(s)
- Sonia Duchemin
- Department of Pharmacology, Université de Montréal Montreal, QC, Canada
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35
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Kim KJ, Filosa JA. Advanced in vitro approach to study neurovascular coupling mechanisms in the brain microcirculation. J Physiol 2012; 590:1757-70. [PMID: 22310311 DOI: 10.1113/jphysiol.2011.222778] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
An understanding of the signalling events underlying neurovascular coupling mechanisms in the brain is a crucial step in the development of novel therapeutic approaches for the treatment of cerebrovascular-associated disorders. In this study we present an enhanced in vitro brain slice preparation from male Wistar rat cortical slices that incorporates haemodynamic variables (flow and pressure) into parenchymal arterioles resulting in the development of myogenic tone (28% from maximum dilatation). Moreover, we characterized flow-induced vascular responses, resulting in various degrees of vasoconstrictions and the response to 10 mM K(+) or astrocytic activation with the mGluR agonist, t-ACPD (100 μM), resulting in vasodilatations of 33.6±4.7% and 38.6±4.6%, respectively. Using fluorescence recovery, we determined perfusate velocity to calculate diameter changes under different experimental pH conditions. Using this approach, we demonstrate no significant differences between diameter changes measured using videomicroscopy or predicted from the velocity values obtained using fluorescence recovery after photobleaching. The model is further validated by demonstrating our ability to cannulate arterioles in two brain regions (cortex and supraoptic nucleus of the hypothalamus). Altogether, we believe this is the first study demonstrating successful cannulation and perfusion of parenchymal arterioles while monitoring/estimating luminal diameter and pressure under conditions where flow rates are controlled.
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Affiliation(s)
- Ki Jung Kim
- Department of Physiology, Georgia Health Sciences University, Augusta, GA 30912, USA
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36
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Ludvig N, Switzer RC, Tang HM, Kuzniecky RI. Autoradiographic evidence for the transmeningeal diffusion of muscimol into the neocortex in rats. Brain Res 2012; 1441:1-8. [PMID: 22284621 DOI: 10.1016/j.brainres.2011.12.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Accepted: 12/23/2011] [Indexed: 11/26/2022]
Abstract
Electrophysiological and behavioral studies have demonstrated that muscimol administered through the cranial meninges can prevent focal neocortical seizures. It was proposed that transmeningeal muscimol delivery can be used for the treatment of intractable focal neocortical epilepsy. However, it has not been proved that muscimol administered via the transmeningeal route can penetrate into the neocortex. The purpose of the present study was to solve this problem by using combined autoradiography-histology methods. Four rats were implanted with epidural cups over the parietal cortices. A 50 μL mixture of [³H] muscimol and unlabeled muscimol with a final concentration of 1.0mM was delivered through each cup on the dura mater. After a 1-hour exposure, the muscimol solution was removed and replaced with formalin to trap the transmeningeally diffused molecules. Then the whole brain was fixed transcardially, sectioned, with the sections subjected to autoradiography and thionine counterstaining. Results showed that (1) [³H] muscimol diffused through the meninges into the cortical tissue underlying the epidural cup in all rats. (2) [³H] muscimol-related autoradiography grains were distributed in all six neocortical layers. (3) [³H] muscimol-related autoradiography grains were localized to the cortical area underneath the epidural delivery site and were absent in the cerebral cortical white matter and other brain structures. This study provided evidence that muscimol can be delivered via the transmeningeal route into the neocortical tissue in a spatially controlled manner. The finding further supports the rationale of using transmeningeal muscimol for the treatment of intractable focal neocortical epilepsy.
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Affiliation(s)
- Nandor Ludvig
- NYU Comprehensive Epilepsy Center, New York University School of Medicine/NYU Langone Medical Center, 223 East 34th Street, New York, NY 10016, USA.
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Devor A, Boas DA, Einevoll GT, Buxton RB, Dale AM. Neuronal Basis of Non-Invasive Functional Imaging: From Microscopic Neurovascular Dynamics to BOLD fMRI. NEURAL METABOLISM IN VIVO 2012. [DOI: 10.1007/978-1-4614-1788-0_15] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Pyramidal neurons are "neurogenic hubs" in the neurovascular coupling response to whisker stimulation. J Neurosci 2011; 31:9836-47. [PMID: 21734275 DOI: 10.1523/jneurosci.4943-10.2011] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The whisker-to-barrel cortex is widely used to study neurovascular coupling, but the cellular basis that underlies the perfusion changes is still largely unknown. Here, we identified neurons recruited by whisker stimulation in the rat somatosensory cortex using double immunohistochemistry for c-Fos and markers of glutamatergic and GABAergic neurons, and investigated in vivo their contribution along with that of astrocytes in the evoked perfusion response. Whisker stimulation elicited cerebral blood flow (CBF) increases concomitantly with c-Fos upregulation in pyramidal cells that coexpressed cyclooxygenase-2 (COX-2) and GABA interneurons that coexpressed vasoactive intestinal polypeptide and/or choline acetyltransferase, but not somatostatin or parvalbumin. The evoked CBF response was decreased by blockade of NMDA (MK-801, -37%), group I metabotropic glutamate (MPEP+LY367385, -40%), and GABA-A (picrotoxin, -31%) receptors, but not by GABA-B, VIP, or muscarinic receptor antagonism. Picrotoxin decreased stimulus-induced somatosensory evoked potentials and CBF responses. Combined blockade of GABA-A and NMDA receptors yielded an additive decreasing effect (-61%) of the evoked CBF compared with each antagonist alone, demonstrating cooperation of both excitatory and inhibitory systems in the hyperemic response. Blockade of prostanoid synthesis by inhibiting COX-2 (indomethacin, NS-398), expressed by ∼40% of pyramidal cells but not by astrocytes, impaired the CBF response (-50%). The hyperemic response was also reduced (-40%) after inhibition of astroglial oxidative metabolism or epoxyeicosatrienoic acids synthesis. These results demonstrate that changes in pyramidal cell activity, sculpted by specific types of inhibitory GABA interneurons, drive the CBF response to whisker stimulation and, further, that metabolically active astrocytes are also required.
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Licata SC, Lowen SB, Trksak GH, MacLean RR, Lukas SE. Zolpidem reduces the blood oxygen level-dependent signal during visual system stimulation. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:1645-52. [PMID: 21640782 PMCID: PMC3154455 DOI: 10.1016/j.pnpbp.2011.05.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 05/07/2011] [Accepted: 05/23/2011] [Indexed: 11/30/2022]
Abstract
Zolpidem is a short-acting imidazopyridine hypnotic that binds at the benzodiazepine binding site on specific GABA(A) receptors to enhance fast inhibitory neurotransmission. The behavioral and receptor pharmacology of zolpidem has been studied extensively, but little is known about its neuronal substrates in vivo. In the present within-subject, double-blind, and placebo-controlled study, blood oxygen level-dependent functional magnetic resonance imaging (BOLD fMRI) at 3 Tesla was used to assess the effects of zolpidem within the brain. Healthy participants (n=12) were scanned 60 min after acute oral administration of zolpidem (0, 5, 10, or 20mg), and changes in BOLD signal were measured in the visual cortex during presentation of a flashing checkerboard. Heart rate and oxygen saturation were monitored continuously throughout the session. Zolpidem (10 and 20mg) reduced the robust visual system activation produced by presentation of this stimulus, but had no effects on physiological activity during the fMRI scan. Zolpidem's modulation of the BOLD signal within the visual cortex is consistent with the abundant distribution of GABA(A) receptors localized in this region, as well as previous studies showing a relationship between increased GABA-mediated neuronal inhibition and a reduction in BOLD activation.
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Affiliation(s)
- Stephanie C. Licata
- Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA
| | - Steven B. Lowen
- Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA, Brain Imaging Center, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA
| | - George H. Trksak
- Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA, Sleep Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA
| | - Robert R. MacLean
- Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA
| | - Scott E. Lukas
- Behavioral Psychopharmacology Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA, Brain Imaging Center, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA, Sleep Research Laboratory, McLean Hospital/Harvard Medical School, 115 Mill Street, Belmont MA, 02478, USA
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Radhakrishnan H, Wu W, Boas D, Franceschini MA. Study of neurovascular coupling by modulating neuronal activity with GABA. Brain Res 2010; 1372:1-12. [PMID: 21145313 DOI: 10.1016/j.brainres.2010.11.082] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Revised: 11/05/2010] [Accepted: 11/24/2010] [Indexed: 10/18/2022]
Abstract
Fundamental to the interpretation of neurovascular coupling is determining the neuronal activity that accounts for functional hyperemia. Recently, synaptic and not spiking activity has been found to be responsible for the hemodynamic response. Using pharmacological manipulation in rats, we want to further determine whether the cortical synaptic activity generated by the thalamic input or the subsequent synaptic activity related to secondary cortical processing is driving the hemodynamic response. In this study, we topically applied γ-aminobutyric acid (GABA) in the somatosensory cortex and used electrical forepaw stimulation to evoke neural and vascular activity. In a group of 8 animals, using laminar electrophysiology, we verified that topical application of GABA for 20min does not affect layer IV synaptic activity but reduces subsequent activity in the supragranular and infragranular layers. In another group of 8 animals, we simultaneously measured the electrical and vascular responses with scalp electroencephalography (EEG) and diffuse optical imaging (DOI), respectively. We decomposed somatosensory evoked potentials (SEP) into three major components: P1, N1, and P2, where P1 represents the thalamic input activity originating in layer IV and N1 and P2 represent the subsequent cortical transmissions. We verified that GABA infusion in the somatosensory cortex does not significantly reduce the P1 SEP component but strongly reduces the N1 and P2 components. We found that GABA also elicits a large reduction in the hemodynamic responses, which correlate with the reduction in N1 and P2 components. These results suggest that the hemodynamic response is predominantly driven by cortico-cortical interactions and not by the initial thalamocortical activity in layer IV.
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Affiliation(s)
- Harsha Radhakrishnan
- MGH/MIT/HMS Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital/Harvard Medical School, Charlestown, MA 02129, USA.
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Pericytes in capillaries are contractile in vivo, but arterioles mediate functional hyperemia in the mouse brain. Proc Natl Acad Sci U S A 2010; 107:22290-5. [PMID: 21135230 DOI: 10.1073/pnas.1011321108] [Citation(s) in RCA: 291] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Modern functional imaging techniques of the brain measure local hemodynamic responses evoked by neuronal activity. Capillary pericytes recently were suggested to mediate neurovascular coupling in brain slices, but their role in vivo remains unexplored. We used two-photon microscopy to study in real time pericytes and the dynamic changes of capillary diameter and blood flow in the cortex of anesthetized mice, as well as in brain slices. The thromboxane A(2) analog, 9,11-dideoxy-9α,11α-methanoepoxy Prostaglandin F2α (U46619), induced constrictions in the vicinity of pericytes in a fraction of capillaries, whereas others dilated. The changes in vessel diameter resulted in changes in capillary red blood cell (RBC) flow. In contrast, during brief epochs of seizure activity elicited by local administration of the GABA(A) receptor antagonist, bicuculline, capillary RBC flow increased without pericyte-induced capillary diameter changes. Precapillary arterioles were the smallest vessels to dilate, together with penetrating and pial arterioles. Our results provide in vivo evidence that pericytes can modulate capillary blood flow in the brain, which may be important under pathological conditions. However, our data suggest that precapillary and penetrating arterioles, rather than pericytes in capillaries, are responsible for the blood flow increase induced by neural activity.
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Chi OZ, Hunter C, Liu X, Chi Y, Weiss HR. Effects of GABA(A) receptor blockade on regional cerebral blood flow and blood-brain barrier disruption in focal cerebral ischemia. J Neurol Sci 2010; 301:66-70. [PMID: 21094956 DOI: 10.1016/j.jns.2010.10.024] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 10/14/2010] [Accepted: 10/22/2010] [Indexed: 11/18/2022]
Abstract
In cerebral ischemia, transmission by the inhibitory neurotransmitter, γ-aminobutyric acid (GABA) is altered. This study was performed to determine whether blockade of GABA(A) receptor would affect regional cerebral blood flow (rCBF) and blood-brain barrier (BBB) permeability in a focal ischemic area of the brain. Rats were anesthetized with isoflurane and mechanically ventilated. Fifteen minutes after a permanent middle cerebral artery (MCA) occlusion, one half of the rats were infused with bicuculline 1mg/kg/min iv for 2 min followed by 0.1mg/kg/min iv to the end of the experiment. The other half were infused with normal saline. At one hour after MCA occlusion, rCBF was determined using ¹⁴C-iodoantipyrine and BBB permeability was determined by measuring the transfer coefficient (Ki) of ¹⁴C-α-aminoisobutyric acid. With MCA occlusion, rCBF was decreased in the ischemic cortex (IC) (-70%) in the control rats. In the bicuculline treated rats, the rCBF of the IC was lower (-48%) than the contralateral cortex but higher than the rCBF of the IC of the control rats (+55%). MCA occlusion increased Ki in the IC of the control rats (+72%) and bicuculline administration increased Ki further (+53%) in the IC. Blockade of GABA(A) receptors did not significantly affect rCBF or BBB permeability in the non-ischemic brain regions under isoflurane anesthesia. Our data demonstrated that blockade of GABA(A) receptors increased rCBF and enhanced the BBB disruption in focal cerebral ischemia. Our data suggest that GABA(A) receptors are involved, at least in part, in modulating rCBF and BBB disruption in focal cerebral ischemia.
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Affiliation(s)
- Oak Z Chi
- Department of Anesthesia, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, New Brunswick, NJ 08901-1977, USA.
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Howarth C, Peppiatt-Wildman CM, Attwell D. The energy use associated with neural computation in the cerebellum. J Cereb Blood Flow Metab 2010; 30:403-14. [PMID: 19888288 PMCID: PMC2859342 DOI: 10.1038/jcbfm.2009.231] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 09/25/2009] [Accepted: 10/05/2009] [Indexed: 11/09/2022]
Abstract
The brain's energy supply determines its information processing power, and generates functional imaging signals, which are often assumed to reflect principal neuron spiking. Using measured cellular properties, we analysed how energy expenditure relates to neural computation in the cerebellar cortex. Most energy is used on information processing by non-principal neurons: Purkinje cells use only 18% of the signalling energy. Excitatory neurons use 73% and inhibitory neurons 27% of the energy. Despite markedly different computational architectures, the granular and molecular layers consume approximately the same energy. The blood vessel area supplying glucose and O(2) is spatially matched to energy consumption. The energy cost of storing motor information in the cerebellum was also estimated.
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Affiliation(s)
- Clare Howarth
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | | | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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Kayser C, Petkov CI, Logothetis NK. Multisensory interactions in primate auditory cortex: fMRI and electrophysiology. Hear Res 2009; 258:80-8. [PMID: 19269312 DOI: 10.1016/j.heares.2009.02.011] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 02/25/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
Abstract
Recent studies suggest that multisensory integration does not only occur in higher association cortices but also at early stages of auditory processing, possibly in primary or secondary auditory cortex. Support for such early multisensory influences comes from functional magnetic resonance imaging experiments in humans and monkeys. However we argue that the current understanding of neurovascular coupling and of the neuronal basis underlying the imaging signal does not permit the direct extrapolation from imaging data to properties of neurons in the same region. While imaging can guide subsequent electrophysiological studies, only these can determine whether and how neurons in auditory cortices combine information from multiple modalities. Indeed, electrophysiological studies only partly confirm the findings from imaging studies. While recordings of field potentials reveal strong influences of visual or somatosensory stimulation on synaptic activity even in primary auditory cortex, single unit studies find only a small minority of neurons as being influenced by non-acoustic stimuli. We propose the analysis of the information coding properties of individual neurons as one way to quantitatively determine whether the representation of our acoustic environment in (primary) auditory cortex indeed benefits from multisensory input.
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Affiliation(s)
- Christoph Kayser
- Max Planck Institute for Biological Cybernetics, Spemannstrasse 38, 72076 Tübingen, Germany.
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Identification and comparison of stochastic metabolic/hemodynamic models (sMHM) for the generation of the BOLD signal. J Comput Neurosci 2008; 26:251-69. [PMID: 18836824 DOI: 10.1007/s10827-008-0109-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 12/19/2007] [Accepted: 02/26/2008] [Indexed: 10/21/2022]
Abstract
This paper extends a previously formulated deterministic metabolic/hemodynamic model for the generation of blood oxygenated level dependent (BOLD) responses to include both physiological and observation stochastic components (sMHM). This adds a degree of flexibility when fitting the model to actual data by accounting for un-modelled activity. We then show how the innovation method can be used to estimate unobserved metabolic/hemodynamic as well as vascular variables of the sMHM, from simulated and actual BOLD data. The proposed estimation method allowed for doing model comparison by calculating the model's AIC and BIC. This methodology was then used to select between different neurovascular coupling assumptions underlying sMHM. The proposed framework was first validated on simulations and then applied to BOLD data from a motor task experiment. The models under comparison in the analysis of the actual data considered that vascular response was coupled to: (I) inhibition, (II) excitation, (III) both excitation and inhibition. Data was best described by model II, although model III was also supported.
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Bartels A, Logothetis NK, Moutoussis K. fMRI and its interpretations: an illustration on directional selectivity in area V5/MT. Trends Neurosci 2008; 31:444-53. [PMID: 18676033 DOI: 10.1016/j.tins.2008.06.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 06/30/2008] [Accepted: 06/30/2008] [Indexed: 10/21/2022]
Abstract
fMRI is a tool to study brain function noninvasively that can reliably identify sites of neural involvement for a given task. However, to what extent can fMRI signals be related to measures obtained in electrophysiology? Can the blood-oxygen-level-dependent signal be interpreted as spatially pooled spiking activity? Here we combine knowledge from neurovascular coupling, functional imaging and neurophysiology to discuss whether fMRI has succeeded in demonstrating one of the most established functional properties in the visual brain, namely directional selectivity in the motion-processing region V5/MT+. We also discuss differences of fMRI and electrophysiology in their sensitivity to distinct physiological processes. We conclude that fMRI constitutes a complement, not a poor-resolution substitute, to invasive techniques, and that it deserves interpretations that acknowledge its stand as a separate signal.
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Affiliation(s)
- Andreas Bartels
- Max Planck Institute for Biological Cybernetics, 72076 Tübingen, Germany.
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Riera JJ, Schousboe A, Waagepetersen HS, Howarth C, Hyder F. The micro-architecture of the cerebral cortex: functional neuroimaging models and metabolism. Neuroimage 2008; 40:1436-59. [PMID: 18343162 PMCID: PMC4348032 DOI: 10.1016/j.neuroimage.2007.12.051] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Revised: 12/19/2007] [Accepted: 12/20/2007] [Indexed: 01/22/2023] Open
Abstract
In order to interpret/integrate data obtained with different functional neuroimaging modalities (e.g. fMRI, EEG/MEG, PET/SPECT, fNIRS), forward-generative models of a diversity of brain mechanisms at the mesoscopic level are considered necessary. For the cerebral cortex, the brain structure with possibly the most relevance for functional neuroimaging, a variety of such biophysical models has been proposed over the last decade. The development of technological tools to investigate in vitro the physiological, anatomical and biochemical principles at the microscopic scale in comparative studies formed the basis for such theoretical progresses. However, with the most recent introduction of systems to record electrical (e.g. miniaturized probes chronically/acutely implantable in the brain), optical (e.g. two-photon laser scanning microscopy) and atomic nuclear spectral (e.g. nuclear magnetic resonance spectroscopy) signals using living laboratory animals, the field is receiving even greater attention. Major advances have been achieved by combining such sophisticated recording systems with new experimental strategies (e.g. transgenic/knock-out animals, high resolution stereotaxic manipulation systems for probe-guidance and cellular-scale chemical-delivery). Theoreticians may now be encouraged to re-consider previously formulated mesoscopic level models in order to incorporate important findings recently made at the microscopic scale. In this series of reviews, we summarize the background at the microscopic scale, which we suggest will constitute the foundations for upcoming representations at the mesoscopic level. In this first part, we focus our attention on the nerve ending particles in order to summarize basic principles and mechanisms underlying cellular metabolism in the cerebral cortex. It will be followed by two parts highlighting major features in its organization/working-principles to regulate both cerebral blood circulation and neuronal activity, respectively. Contemporary theoretical models for functional neuroimaging will be revised in the fourth part, with particular emphasis in their applications, advantages/limitations and future prospects.
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Affiliation(s)
- Jorge J Riera
- Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan.
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Kocharyan A, Fernandes P, Tong XK, Vaucher E, Hamel E. Specific subtypes of cortical GABA interneurons contribute to the neurovascular coupling response to basal forebrain stimulation. J Cereb Blood Flow Metab 2008; 28:221-31. [PMID: 17895909 DOI: 10.1038/sj.jcbfm.9600558] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurovascular coupling, or the tight coupling between neuronal activity and regional cerebral blood flow (CBF), seems largely driven by the local processing of incoming afferent signals within the activated area. To test if cortical gamma-aminobutyric acid (GABA) interneurons-the local integrators of cortical activity-are involved in this coupling, we stimulated the basalocortical pathway in vivo, monitored cortical CBF, and identified the activated interneurons (c-Fos-immunopositive) and the neuromediators involved in this response. Basal forebrain (BF) stimulation induced ipsilateral increases in CBF and selective activation of layers II to VI somatostatin- and/or neuropeptide Y-containing, as well as layer I GABA interneurons. Nitric oxide synthase interneurons displayed weak bilateral activation, whereas vasoactive intestinal polypeptide- or acetylcholine (ACh)-containing GABA interneurons were not activated. Selective cholinergic deafferentation indicated that ACh released from stimulated BF afferents triggered the CBF response, but the latter was mediated, in part, by the local release of GABA from cholinoceptive cortical interneurons, and through GABA-A receptor-mediated transmission. These data show that activation of specific subsets of GABA interneurons and their GABA-A-mediated effects on neuronal, vascular, and/or astroglial targets are necessary for the full expression of the hemodynamic response to BF stimulation. Further, these findings highlight the importance of understanding the cellular networks and circuitry that underlie hemodynamic signals, as only specific subsets of neurons may be activated by a given stimulus, depending on the afferent inputs they receive and integrate.
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Affiliation(s)
- Ara Kocharyan
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, Montréal, Québec, Canada
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Abstract
Whatever the pathogenesis of syncope is, the ultimate common cause leading to loss of consciousness is insufficient cerebral perfusion with a critical reduction of blood flow to the reticular activating system. Brain circulation has an autoregulation system that keeps cerebral blood flow constant over a wide range of systemic blood pressures. Normally, if blood pressure decreases, autoregulation reacts with a reduction in cerebral vascular resistance, in an attempt to prevent cerebral hypoperfusion. However, in some cases, particularly in neurally mediated syncope, it can also be harmful, being actively implicated in a paradox reflex that induces an increase in cerebrovascular resistance and contributes to the critical reduction of cerebral blood flow. This review outlines the anatomic structures involved in cerebral autoregulation, its mechanisms, in normal and pathologic conditions, and the noninvasive neuroimaging techniques used in the study of cerebral circulation and autoregulation. An emphasis is placed on the description of autoregulation pathophysiology in orthostatic and neurally mediated syncope.
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Lok J, Gupta P, Guo S, Kim WJ, Whalen MJ, van Leyen K, Lo EH. Cell-cell signaling in the neurovascular unit. Neurochem Res 2007; 32:2032-45. [PMID: 17457674 DOI: 10.1007/s11064-007-9342-9] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 03/23/2007] [Indexed: 12/13/2022]
Abstract
Historically, the neuron has been the conceptual focus for almost all of neuroscience research. In recent years, however, the concept of the neurovascular unit has emerged as a new paradigm for investigating both physiology and pathology in the CNS. This concept proposes that a purely neurocentric focus is not sufficient, and emphasizes that all cell types in the brain including neuronal, glial and vascular components, must be examined in an integrated context. Cell-cell signaling and coupling between these different compartments form the basis for normal function. Disordered signaling and perturbed coupling form the basis for dysfunction and disease. In this mini-review, we will survey four examples of this phenomenon: hemodynamic neurovascular coupling linking blood flow to brain activity; cellular communications that evoke the blood-brain barrier phenotype; parallel systems that underlie both neurogenesis and angiogenesis in the CNS; and finally, the potential exchange of trophic factors that may link neuronal, glial and vascular homeostasis.
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Affiliation(s)
- Josephine Lok
- Neuroprotection Research Laboratory, Department of Radiology, Massachusetts General Hospital, MGH East 149-2401, Charlestown, MA 02129, USA
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