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Hike D, Liu X, Xie Z, Zhang B, Choi S, Zhou XA, Liu A, Murstein A, Jiang Y, Devor A, Yu X. High-resolution awake mouse fMRI at 14 Tesla. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.12.08.570803. [PMID: 38106227 PMCID: PMC10723470 DOI: 10.1101/2023.12.08.570803] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
High-resolution awake mouse fMRI remains challenging despite extensive efforts to address motion-induced artifacts and stress. This study introduces an implantable radiofrequency (RF) surface coil design that minimizes image distortion caused by the air/tissue interface of mouse brains while simultaneously serving as a headpost for fixation during scanning. Furthermore, this study provides a thorough acclimation method used to accustom animals to the MRI environment minimizing motion induced artifacts. Using a 14T scanner, high-resolution fMRI enabled brain-wide functional mapping of visual and vibrissa stimulation at 100×100×200μm resolution with a 2s per frame sampling rate. Besides activated ascending visual and vibrissa pathways, robust BOLD responses were detected in the anterior cingulate cortex upon visual stimulation and spread through the ventral retrosplenial area (VRA) with vibrissa air-puff stimulation, demonstrating higher-order sensory processing in association cortices of awake mice. In particular, the rapid hemodynamic responses in VRA upon vibrissa stimulation showed a strong correlation with the hippocampus, thalamus, and prefrontal cortical areas. Cross-correlation analysis with designated VRA responses revealed early positive BOLD signals at the contralateral barrel cortex (BC) occurring 2 seconds prior to the air-puff in awake mice with repetitive stimulation, which was not detected using a randomized stimulation paradigm. This early BC activation indicated a learned anticipation through the vibrissa system and association cortices in awake mice under continuous training of repetitive air-puff stimulation. This work establishes a high-resolution awake mouse fMRI platform, enabling brain-wide functional mapping of sensory signal processing in higher association cortical areas.
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Affiliation(s)
- David Hike
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Xiaochen Liu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Zeping Xie
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Bei Zhang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Sangcheon Choi
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Xiaoqing Alice Zhou
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Andy Liu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
- Graduate program in Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, Massachusetts, USA, 02215
| | - Alyssa Murstein
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
- Graduate program in Neuroscience, Boston University, 610 Commonwealth Avenue, Boston, Massachusetts, USA, 02215
| | - Yuanyuan Jiang
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
| | - Anna Devor
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
- Department of Biomedical Engineering, Boston University, 610 Commonwealth Avenue, Boston, Massachusetts, USA, 02215
| | - Xin Yu
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, 149 Thirteenth Street, Charlestown, Massachusetts, USA 02129
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2
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Choi S, Hike D, Pohmann R, Avdievich N, Gomez-Cid L, Man W, Scheffler K, Yu X. Alpha-180 spin-echo based line-scanning method for high resolution laminar-specific fMRI. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.09.540065. [PMID: 37214920 PMCID: PMC10197646 DOI: 10.1101/2023.05.09.540065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Laminar-specific functional magnetic resonance imaging (fMRI) has been widely used to study circuit-specific neuronal activity by mapping spatiotemporal fMRI response patterns across cortical layers. Hemodynamic responses reflect indirect neuronal activity given limit of spatial and temporal resolution. Previous gradient-echo based line-scanning fMRI (GELINE) method was proposed with high temporal (50 ms) and spatial (50 µm) resolution to better characterize the fMRI onset time across cortical layers by employing 2 saturation RF pulses. However, the imperfect RF saturation performance led to poor boundary definition of the reduced region of interest (ROI) and aliasing problems outside of the ROI. Here, we propose α (alpha)-180 spin-echo-based line-scanning fMRI (SELINE) method to resolve this issue by employing a refocusing 180° RF pulse perpendicular to the excitation slice. In contrast to GELINE signals peaked at the superficial layer, we detected varied peaks of laminar-specific BOLD signals across deeper cortical layers with the SELINE method, indicating the well-defined exclusion of the large drain-vein effect with the spin-echo sequence. Furthermore, we applied the SELINE method with 200 ms TR to sample the fast hemodynamic changes across cortical layers with a less draining vein effect. In summary, this SELINE method provides a novel acquisition scheme to identify microvascular-sensitive laminar-specific BOLD responses across cortical depth.
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3
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Cauli B, Dusart I, Li D. Lactate as a determinant of neuronal excitability, neuroenergetics and beyond. Neurobiol Dis 2023:106207. [PMID: 37331530 DOI: 10.1016/j.nbd.2023.106207] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/13/2023] [Accepted: 06/15/2023] [Indexed: 06/20/2023] Open
Abstract
Over the last decades, lactate has emerged as important energy substrate for the brain fueling of neurons. A growing body of evidence now indicates that it is also a signaling molecule modulating neuronal excitability and activity as well as brain functions. In this review, we will briefly summarize how different cell types produce and release lactate. We will further describe different signaling mechanisms allowing lactate to fine-tune neuronal excitability and activity, and will finally discuss how these mechanisms could cooperate to modulate neuroenergetics and higher order brain functions both in physiological and pathological conditions.
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Affiliation(s)
- Bruno Cauli
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 9 quai Saint Bernard, 75005 Paris, France.
| | - Isabelle Dusart
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 9 quai Saint Bernard, 75005 Paris, France
| | - Dongdong Li
- Sorbonne Université, CNRS, INSERM, Neurosciences Paris Seine - Institut de Biologie Paris Seine (NPS-IBPS), 9 quai Saint Bernard, 75005 Paris, France
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4
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Suzuki H, Takeda H, Takuwa H, Ji B, Higuchi M, Kanno I, Masamoto K. Capillary responses to functional and pathological activations rely on the capillary states at rest. J Cereb Blood Flow Metab 2023; 43:1010-1024. [PMID: 36752020 PMCID: PMC10196750 DOI: 10.1177/0271678x231156372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 01/09/2023] [Accepted: 01/19/2023] [Indexed: 02/09/2023]
Abstract
Brain capillaries play a crucial role in maintaining cellular viability and thus preventing neurodegeneration. The aim of this study was to characterize the brain capillary morphology at rest and during neural activation based on a big data analysis from three-dimensional microangiography. Neurovascular responses were measured using a genetic calcium sensor expressed in neurons and microangiography with two-photon microscopy, while neural acivity was modulated by stimulation of contralateral whiskers or by a seizure evoked by kainic acid. For whisker stimulation, 84% of the capillary sites showed no detectable diameter change. The remaining 10% and 6% were dilated and constricted, respectively. Significant differences were observed for capillaries in the diameter at rest between the locations of dilation and constriction. Even the seizures resulted in 44% of the capillaries having no detectable change in diameter, while 56% of the capillaries dilated. The extent of dilation was dependent on the diameter at rest. In conclusion, big data analysis on brain capillary morphology has identified at least two types of capillary states: capillaries with diameters that are relatively large at rest and stable over time regardless of neural activity and capillaries whose diameters are relatively small at rest and vary according to neural activity.
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Affiliation(s)
- Hiroki Suzuki
- Graduate School of
Informatics and Engineering, University of Electro-Communications,
Tokyo, Japan
| | - Hiroshi Takeda
- Graduate School of
Informatics and Engineering, University of Electro-Communications,
Tokyo, Japan
| | - Hiroyuki Takuwa
- Department of Functional
Brain Imaging, National Institutes for Quantum Science and Technology,
Chiba, Japan
| | - Bin Ji
- Department of Functional
Brain Imaging, National Institutes for Quantum Science and Technology,
Chiba, Japan
- Department of Radiopharmacy
and Molecular Imaging, School of Pharmacy, Fudan University, Shanghai,
China
| | - Makoto Higuchi
- Department of Functional
Brain Imaging, National Institutes for Quantum Science and Technology,
Chiba, Japan
| | - Iwao Kanno
- Department of Functional
Brain Imaging, National Institutes for Quantum Science and Technology,
Chiba, Japan
| | - Kazuto Masamoto
- Graduate School of
Informatics and Engineering, University of Electro-Communications,
Tokyo, Japan
- Department of Functional
Brain Imaging, National Institutes for Quantum Science and Technology,
Chiba, Japan
- Center for Neuroscience and
Biomedical Engineering, University of Electro-Communications, Tokyo,
Japan
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5
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Huang J, Zhang Y, Zhang Q, Wei L, Zhang X, Jin C, Yang J, Li Z, Liang S. The current status and trend of the functional magnetic resonance combined with stimulation in animals. Front Neurosci 2022; 16:963175. [PMID: 36213733 PMCID: PMC9540855 DOI: 10.3389/fnins.2022.963175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/05/2022] [Indexed: 11/16/2022] Open
Abstract
As a non-radiative, non-invasive imaging technique, functional magnetic resonance imaging (fMRI) has excellent effects on studying the activation of blood oxygen levels and functional connectivity of the brain in human and animal models. Compared with resting-state fMRI, fMRI combined with stimulation could be used to assess the activation of specific brain regions and the connectivity of specific pathways and achieve better signal capture with a clear purpose and more significant results. Various fMRI methods and specific stimulation paradigms have been proposed to investigate brain activation in a specific state, such as electrical, mechanical, visual, olfactory, and direct brain stimulation. In this review, the studies on animal brain activation using fMRI combined with different stimulation methods were retrieved. The instruments, experimental parameters, anesthesia, and animal models in different stimulation conditions were summarized. The findings would provide a reference for studies on estimating specific brain activation using fMRI combined with stimulation.
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Sanganahalli BG, Thompson GJ, Parent M, Verhagen JV, Blumenfeld H, Herman P, Hyder F. Thalamic activations in rat brain by fMRI during tactile (forepaw, whisker) and non-tactile (visual, olfactory) sensory stimulations. PLoS One 2022; 17:e0267916. [PMID: 35522646 PMCID: PMC9075615 DOI: 10.1371/journal.pone.0267916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/18/2022] [Indexed: 11/18/2022] Open
Abstract
The thalamus is a crucial subcortical hub that impacts cortical activity. Tracing experiments in animals and post-mortem humans suggest rich morphological specificity of the thalamus. Very few studies reported rodent thalamic activations by functional MRI (fMRI) as compared to cortical activations for different sensory stimuli. Here, we show different portions of the rat thalamus in response to tactile (forepaw, whisker) and non-tactile (visual, olfactory) sensory stimuli with high field fMRI (11.7T) using a custom-build quadrature surface coil to capture high sensitivity signals from superficial and deep brain regions simultaneously. Results demonstrate reproducible thalamic activations during both tactile and non-tactile stimuli. Forepaw and whisker stimuli activated broader regions within the thalamus: ventral posterior lateral (VPL), ventral posterior medial (VPM), lateral posterior mediorostral (LPMR) and posterior medial (POm) thalamic nuclei. Visual stimuli activated dorsal lateral geniculate nucleus (DLG) of the thalamus but also parts of the superior/inferior colliculus, whereas olfactory stimuli activated specifically the mediodorsal nucleus of the thalamus (MDT). BOLD activations in LGN and MDT were much stronger than in VPL, VPM, LPMR and POm. These fMRI-based thalamic activations suggest that forepaw and whisker (i.e., tactile) stimuli engage VPL, VPM, LPMR and POm whereas visual and olfactory (i.e., non-tactile) stimuli, respectively, recruit DLG and MDT exclusively.
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Affiliation(s)
- Basavaraju G. Sanganahalli
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, United States of America
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, United States of America
| | - Garth J. Thompson
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, United States of America
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, United States of America
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Maxime Parent
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, United States of America
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, United States of America
| | - Justus V. Verhagen
- The John B. Pierce Laboratory, New Haven, Connecticut, United States of America
- Department of Neuroscience, Yale University, New Haven, Connecticut, United States of America
| | - Hal Blumenfeld
- Department of Neuroscience, Yale University, New Haven, Connecticut, United States of America
- Department of Neurology, Yale University, New Haven, Connecticut, United States of America
- Department of Neurosurgery, Yale University, New Haven, Connecticut, United States of America
| | - Peter Herman
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, United States of America
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, United States of America
| | - Fahmeed Hyder
- Magnetic Resonance Research Center (MRRC), Yale University, New Haven, Connecticut, United States of America
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, Connecticut, United States of America
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, United States of America
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7
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Han S, Eun S, Cho H, Uludaǧ K, Kim SG. Improvement of sensitivity and specificity for laminar BOLD fMRI with double spin-echo EPI in humans at 7 T. Neuroimage 2021; 241:118435. [PMID: 34324976 DOI: 10.1016/j.neuroimage.2021.118435] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2021] [Accepted: 07/26/2021] [Indexed: 12/19/2022] Open
Abstract
Mapping mesoscopic cortical functional units such as columns or laminae is increasingly pursued by ultra-high field (UHF) functional magnetic resonance imaging (fMRI). The most popular approach for high-resolution fMRI is currently gradient-echo (GE) blood oxygenation level-dependent (BOLD) fMRI. However, its spatial accuracy is reduced due to its sensitivity to draining vessels, including pial veins, whereas spin-echo (SE) BOLD signal is expected to have higher spatial accuracy, albeit with lower sensitivity than the GE-BOLD signal. Here, we introduce a new double spin-echo (dSE) echo-planar imaging (EPI) method to improve the sensitivity of SE-BOLD contrast by averaging two spin-echoes using three radiofrequency pulses. Human fMRI experiments were performed with slices perpendicular to the central sulcus between motor and sensory cortices at 7 T during fist-clenching with touching. First, we evaluated the feasibility of single-shot dSE-EPI for BOLD fMRI with 1.5 mm isotropic resolution and found that dSE-BOLD fMRI has higher signal-to-noise ratio (SNR), temporal SNR (tSNR), and higher functional sensitivity than conventional SE-BOLD fMRI. Second, to investigate the laminar specificity of dSE-BOLD fMRI, we implemented a multi-shot approach to achieve 0.8-mm isotropic resolution with sliding-window reconstruction. Unlike GE-BOLD fMRI, the cortical profile of dSE-BOLD fMRI peaked at ~ 1.0 mm from the surface of the primary motor and sensory cortices, demonstrating an improvement of laminar specificity in humans over GE-BOLD fMRI. The proposed multi-shot dSE-EPI method is viable for high spatial resolution UHF-fMRI studies in the pursuit of resolving mesoscopic functional units.
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Affiliation(s)
- SoHyun Han
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea.
| | - Seulgi Eun
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea
| | - HyungJoon Cho
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Kâmil Uludaǧ
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Techna Institute & Koerner Scientist in MR Imaging, University Health Network, Toronto, Canada
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science (IBS), Suwon, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Republic of Korea; Department of Intelligent Precision Healthcare Convergence, Sungkyunkwan University, Suwon, Republic of Korea.
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8
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One-pot synthesis of carboxymethyl-dextran coated iron oxide nanoparticles (CION) for preclinical fMRI and MRA applications. Neuroimage 2021; 238:118213. [PMID: 34116153 PMCID: PMC8418149 DOI: 10.1016/j.neuroimage.2021.118213] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 05/15/2021] [Accepted: 05/25/2021] [Indexed: 11/21/2022] Open
Abstract
Superparamagnetic iron-oxide nanoparticles are robust contrast agents for magnetic resonance imaging (MRI) used for sensitive structural and functional mapping of the cerebral blood volume (CBV) when administered intravenously. To date, many CBV-MRI studies are conducted with Feraheme, manufactured for the clinical treatment of iron-deficiency. Unfortunately, Feraheme is currently not available outside the United States due to commercial and regulatory constraints, making CBV-MRI methods either inaccessible or very costly to achieve. To address this barrier, we developed a simple, one-pot recipe to synthesize Carboxymethyl-dextran coated Iron Oxide Nanoparticles, namely, “CION”, suitable for preclinical CBV-MRI applications. Here we disseminate a step-by-step instruction of our one-pot synthesis protocol, which allows CION to be produced in laboratories with minimal cost. We also characterized different CION-conjugations by manipulating polymer to metal stoichiometric ratio in terms of their size, surface chemistry, and chemical composition, and shifts in MR relaxivity and pharmacokinetics. We performed several proof-of-concept experiments in vivo, demonstrating the utility of CION for functional and structural MRI applications, including hypercapnic CO2 challenge, visual stimulation, targeted optogenetic stimulation, and microangiography. We also present evidence that CION can serve as a cross-modality research platform by showing concurrent in vivo optical and MRI measurement of CBV using fluorescent-labeled CION. The simplicity and cost-effectiveness of our one-pot synthesis method should allow researchers to reproduce CION and tailor the relaxivity and pharmacokinetics according to their imaging needs. It is our hope that this work makes CBV-MRI more openly available and affordable for a variety of research applications.
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9
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Huber LR, Poser BA, Kaas AL, Fear EJ, Dresbach S, Berwick J, Goebel R, Turner R, Kennerley AJ. Validating layer-specific VASO across species. Neuroimage 2021; 237:118195. [PMID: 34038769 DOI: 10.1016/j.neuroimage.2021.118195] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 05/17/2021] [Accepted: 05/19/2021] [Indexed: 01/27/2023] Open
Abstract
Cerebral blood volume (CBV) has been shown to be a robust and important physiological parameter for quantitative interpretation of functional (f)MRI, capable of delivering highly localized mapping of neural activity. Indeed, with recent advances in ultra-high-field (≥7T) MRI hardware and associated sequence libraries, it has become possible to capture non-invasive CBV weighted fMRI signals across cortical layers. One of the most widely used approaches to achieve this (in humans) is through vascular-space-occupancy (VASO) fMRI. Unfortunately, the exact contrast mechanisms of layer-dependent VASO fMRI have not been validated for human fMRI and thus interpretation of such data is confounded. Here we validate the signal source of layer-dependent SS-SI VASO fMRI using multi-modal imaging in a rat model in response to neuronal activation (somatosensory cortex) and respiratory challenge (hypercapnia). In particular VASO derived CBV measures are directly compared to concurrent measures of total haemoglobin changes from high resolution intrinsic optical imaging spectroscopy (OIS). Quantified cortical layer profiling is demonstrated to be in agreement between VASO and contrast enhanced fMRI (using monocrystalline iron oxide nanoparticles, MION). Responses show high spatial localisation to layers of cortical processing independent of confounding large draining veins which can hamper BOLD fMRI studies, (depending on slice positioning). Thus, a cross species comparison is enabled using VASO as a common measure. We find increased VASO based CBV reactivity (3.1 ± 1.2 fold increase) in humans compared to rats. Together, our findings confirm that the VASO contrast is indeed a reliable estimate of layer-specific CBV changes. This validation study increases the neuronal interpretability of human layer-dependent VASO fMRI as an appropriate method in neuroscience application studies, in which the presence of large draining intracortical and pial veins limits neuroscientific inference with BOLD fMRI.
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Affiliation(s)
- Laurentius Renzo Huber
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands.
| | - Benedikt A Poser
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Amanda L Kaas
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Elizabeth J Fear
- Hull-York-Medical-School (HYMS), University of York, York, United Kingdom
| | - Sebastian Dresbach
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Jason Berwick
- Department of Psychology, University of Sheffield, Sheffield, United Kingdom
| | - Rainer Goebel
- MBIC, Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, the Netherlands
| | - Robert Turner
- Neurophysics Department Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom
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10
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Mocanu VM, Shmuel A. Optical Imaging-Based Guidance of Viral Microinjections and Insertion of a Laminar Electrophysiology Probe Into a Predetermined Barrel in Mouse Area S1BF. Front Neural Circuits 2021; 15:541676. [PMID: 34054436 PMCID: PMC8158817 DOI: 10.3389/fncir.2021.541676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 03/31/2021] [Indexed: 12/04/2022] Open
Abstract
Wide-field Optical Imaging of Intrinsic Signals (OI-IS; Grinvald et al., 1986) is a method for imaging functional brain hemodynamic responses, mainly used to image activity from the surface of the cerebral cortex. It localizes small functional modules – such as cortical columns – with great spatial resolution and spatial specificity relative to the site of increases in neuronal activity. OI-IS is capable of imaging responses either through an intact or thinned skull or following a craniotomy. Therefore, it is minimally invasive, which makes it ideal for survival experiments. Here we describe OI-IS-based methods for guiding microinjections of optogenetics viral vectors in proximity to small functional modules (S1 barrels) of the cerebral cortex and for guiding the insertion of electrodes for electrophysiological recording into such modules. We validate our proposed methods by tissue processing of the cerebral barrel field area, revealing the track of the electrode in a predetermined barrel. In addition, we demonstrate the use of optical imaging to visualize the spatial extent of the optogenetics photostimulation, making it possible to estimate one of the two variables that conjointly determine which region of the brain is stimulated. Lastly, we demonstrate the use of OI-IS at high-magnification for imaging the upper recording contacts of a laminar probe, making it possible to estimate the insertion depth of all contacts relative to the surface of the cortex. These methods support the precise positioning of microinjections and recording electrodes, thus overcoming the variability in the spatial position of fine-scale functional modules.
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Affiliation(s)
- Victor M Mocanu
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Amir Shmuel
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, QC, Canada.,Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada.,Department of Physiology, McGill University, Montreal, QC, Canada.,Department of Biomedical Engineering, McGill University, Montreal, QC, Canada
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11
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Markuerkiaga I, Marques JP, Bains LJ, Norris DG. An in-vivo study of BOLD laminar responses as a function of echo time and static magnetic field strength. Sci Rep 2021; 11:1862. [PMID: 33479362 PMCID: PMC7820587 DOI: 10.1038/s41598-021-81249-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 12/22/2020] [Indexed: 11/18/2022] Open
Abstract
Layer specific functional MRI requires high spatial resolution data. To compensate the associated poor signal to noise ratio it is common to integrate the signal from voxels at a given cortical depth. If the region is sufficiently large then physiological noise will be the dominant noise source. In this work, activation profiles in response to the same visual stimulus are compared at 1.5 T, 3 T and 7 T using a multi-echo, gradient echo (GE) FLASH sequence, with a 0.75 mm isotropic voxel size and the cortical integration approach. The results show that after integrating over a cortical volume of 40, 60 and 100 mm3 (at 7 T, 3 T, and 1.5 T, respectively), the signal is in the physiological noise dominated regime. The activation profiles obtained are similar for equivalent echo times. BOLD-like noise is found to be the dominant source of physiological noise. Consequently, the functional contrast to noise ratio is not strongly echo-time or field-strength dependent. We conclude that laminar GE-BOLD fMRI at lower field strengths is feasible but that larger patches of cortex will need to be examined, and that the acquisition efficiency is reduced.
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Affiliation(s)
- Irati Markuerkiaga
- Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - José P Marques
- Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - Lauren J Bains
- Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands
| | - David G Norris
- Donders Centre for Cognitive Neuroimaging, Radboud University, Nijmegen, The Netherlands. .,Erwin L. Hahn Institute for Magnetic Resonance Imaging, 45141, Essen, Germany.
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12
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van Dijk JA, Fracasso A, Petridou N, Dumoulin SO. Validating Linear Systems Analysis for Laminar fMRI: Temporal Additivity for Stimulus Duration Manipulations. Brain Topogr 2021; 34:88-101. [PMID: 33210193 PMCID: PMC7803719 DOI: 10.1007/s10548-020-00808-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 11/05/2020] [Indexed: 11/26/2022]
Abstract
Advancements in ultra-high field (7 T and higher) magnetic resonance imaging (MRI) scanners have made it possible to investigate both the structure and function of the human brain at a sub-millimeter scale. As neuronal feedforward and feedback information arrives in different layers, sub-millimeter functional MRI has the potential to uncover information processing between cortical micro-circuits across cortical depth, i.e. laminar fMRI. For nearly all conventional fMRI analyses, the main assumption is that the relationship between local neuronal activity and the blood oxygenation level dependent (BOLD) signal adheres to the principles of linear systems theory. For laminar fMRI, however, directional blood pooling across cortical depth stemming from the anatomy of the cortical vasculature, potentially violates these linear system assumptions, thereby complicating analysis and interpretation. Here we assess whether the temporal additivity requirement of linear systems theory holds for laminar fMRI. We measured responses elicited by viewing stimuli presented for different durations and evaluated how well the responses to shorter durations predicted those elicited by longer durations. We find that BOLD response predictions are consistently good predictors for observed responses, across all cortical depths, and in all measured visual field maps (V1, V2, and V3). Our results suggest that the temporal additivity assumption for linear systems theory holds for laminar fMRI. We thus show that the temporal additivity assumption holds across cortical depth for sub-millimeter gradient-echo BOLD fMRI in early visual cortex.
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Affiliation(s)
- Jelle A van Dijk
- Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands.
- Experimental Psychology, Utrecht University, Utrecht, The Netherlands.
| | - Alessio Fracasso
- Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, G12 8QB, UK
- Radiology Department, Imaging Division, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Natalia Petridou
- Radiology Department, Imaging Division, Center for Image Sciences, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Serge O Dumoulin
- Spinoza Centre for Neuroimaging, Amsterdam, The Netherlands
- Experimental Psychology, Utrecht University, Utrecht, The Netherlands
- Experimental and Applied Psychology, VU University, Amsterdam, The Netherlands
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13
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van Dijk JA, Fracasso A, Petridou N, Dumoulin SO. Linear systems analysis for laminar fMRI: Evaluating BOLD amplitude scaling for luminance contrast manipulations. Sci Rep 2020; 10:5462. [PMID: 32214136 PMCID: PMC7096513 DOI: 10.1038/s41598-020-62165-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 03/09/2020] [Indexed: 01/18/2023] Open
Abstract
A fundamental assumption of nearly all functional magnetic resonance imaging (fMRI) analyses is that the relationship between local neuronal activity and the blood oxygenation level dependent (BOLD) signal can be described as following linear systems theory. With the advent of ultra-high field (7T and higher) MRI scanners, it has become possible to perform sub-millimeter resolution fMRI in humans. A novel and promising application of sub-millimeter fMRI is measuring responses across cortical depth, i.e. laminar imaging. However, the cortical vasculature and associated directional blood pooling towards the pial surface strongly influence the cortical depth-dependent BOLD signal, particularly for gradient-echo BOLD. This directional pooling may potentially affect BOLD linearity across cortical depth. Here we assess whether the amplitude scaling assumption for linear systems theory holds across cortical depth. For this, we use stimuli with different luminance contrasts to elicit different BOLD response amplitudes. We find that BOLD amplitude across cortical depth scales with luminance contrast, and that this scaling is identical across cortical depth. Although nonlinearities may be present for different stimulus configurations and acquisition protocols, our results suggest that the amplitude scaling assumption for linear systems theory across cortical depth holds for luminance contrast manipulations in sub-millimeter laminar BOLD fMRI.
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Affiliation(s)
- Jelle A van Dijk
- Experimental Psychology, Utrecht University, Utrecht, NL, Netherlands.
- Spinoza Centre for Neuroimaging, Amsterdam, NL, Netherlands.
| | - Alessio Fracasso
- Spinoza Centre for Neuroimaging, Amsterdam, NL, Netherlands
- Institute of Neuroscience and Psychology, University of Glasgow, Glasgow, G12 8QB, UK
- Radiology Department, Imaging Division, Center for Image Sciences, University Medical Center Utrecht, Utrecht, NL, Netherlands
| | - Natalia Petridou
- Radiology Department, Imaging Division, Center for Image Sciences, University Medical Center Utrecht, Utrecht, NL, Netherlands
| | - Serge O Dumoulin
- Experimental Psychology, Utrecht University, Utrecht, NL, Netherlands
- Spinoza Centre for Neuroimaging, Amsterdam, NL, Netherlands
- Experimental and Applied Psychology, VU University, Amsterdam, NL, Netherlands
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14
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Jaime S, Gu H, Sadacca BF, Stein EA, Cavazos JE, Yang Y, Lu H. Delta Rhythm Orchestrates the Neural Activity Underlying the Resting State BOLD Signal via Phase-amplitude Coupling. Cereb Cortex 2020; 29:119-133. [PMID: 29161352 DOI: 10.1093/cercor/bhx310] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/25/2017] [Indexed: 12/11/2022] Open
Abstract
Spontaneous ongoing neuronal activity is a prominent feature of the mammalian brain. Temporal and spatial patterns of such ongoing activity have been exploited to examine large-scale brain network organization and function. However, the neurophysiological basis of this spontaneous brain activity as detected by resting-state functional Magnetic Resonance Imaging (fMRI) remains poorly understood. To this end, multi-site local field potentials (LFP) and blood oxygenation level-dependent (BOLD) fMRI were simultaneously recorded in the rat striatum along with local pharmacological manipulation of striatal activity. Results demonstrate that delta (δ) band LFP power negatively, while beta (β) and gamma (γ) band LFPs positively correlated with BOLD fluctuation. Furthermore, there was strong cross-frequency phase-amplitude coupling (PAC), with the phase of δ LFPs significantly modulating the amplitude of the high frequency signal. Enhancing dopaminergic neuronal activity significantly reduced ventral striatal functional connectivity, δ LFP-BOLD correlation, and the PAC effect. These data suggest that different frequency bands of the LFP contribute distinctively to BOLD spontaneous fluctuation and that PAC is the organizing mechanism through which low frequency LFPs orchestrate neural activity that underlies resting state functional connectivity.
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Affiliation(s)
- Saul Jaime
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA.,Department of Cellular and Integrative Physiology, UT Health-San Antonio, San Antonio, USA
| | - Hong Gu
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA
| | - Brian F Sadacca
- Cellular Neurobiology Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA
| | - Elliot A Stein
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA
| | - Jose E Cavazos
- Graduate School of Biomedical Sciences, UT Health-San Antonio, San Antonio, USA
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA
| | - Hanbing Lu
- Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, USA
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15
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Lander SS, Chornyy S, Safory H, Gross A, Wolosker H, Gaisler‐Salomon I. Glutamate dehydrogenase deficiency disrupts glutamate homeostasis in hippocampus and prefrontal cortex and impairs recognition memory. GENES BRAIN AND BEHAVIOR 2020; 19:e12636. [DOI: 10.1111/gbb.12636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 12/11/2019] [Accepted: 12/30/2019] [Indexed: 12/13/2022]
Affiliation(s)
| | - Sergiy Chornyy
- Department of PsychologyUniversity of Haifa Haifa Israel
| | - Hazem Safory
- Department of Biochemistry, The Ruth and Bruce Rappaport Faculty of MedicineTechnion‐Israel Institute of Technology Haifa Israel
| | - Amit Gross
- Department of PsychologyUniversity of Haifa Haifa Israel
| | - Herman Wolosker
- Department of Biochemistry, The Ruth and Bruce Rappaport Faculty of MedicineTechnion‐Israel Institute of Technology Haifa Israel
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16
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Non-BOLD contrast for laminar fMRI in humans: CBF, CBV, and CMRO2. Neuroimage 2019; 197:742-760. [DOI: 10.1016/j.neuroimage.2017.07.041] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Revised: 07/10/2017] [Accepted: 07/19/2017] [Indexed: 12/22/2022] Open
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18
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Mishra A, Majumdar S, Wang F, Wilson GH, Gore JC, Chen LM. Functional connectivity with cortical depth assessed by resting state fMRI of subregions of S1 in squirrel monkeys. Hum Brain Mapp 2019; 40:329-339. [PMID: 30251760 PMCID: PMC6289644 DOI: 10.1002/hbm.24375] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 08/14/2018] [Accepted: 08/15/2018] [Indexed: 12/15/2022] Open
Abstract
Whereas resting state blood oxygenation-level dependent (BOLD) functional MRI has been widely used to assess functional connectivity between cortical regions, the laminar specificity of such measures is poorly understood. This study aims to determine: (a) whether the resting state functional connectivity (rsFC) between two functionally related cortical regions varies with cortical depth, (b) the relationship between layer-resolved tactile stimulus-evoked activation pattern and interlayer rsFC pattern between two functionally distinct but related somatosensory areas 3b and 1, and (c) the effects of spatial resolution on rsFC measures. We examined the interlayer rsFC between areas 3b and 1 of squirrel monkeys under anesthesia using tactile stimulus-driven and resting state BOLD acquisitions at submillimeter resolution. Consistent with previous observations in the areas 3b and 1, we detected robust stimulus-evoked BOLD activations with foci were confined mainly to the upper layers (centered at 21% of the cortical depth). By carefully placing seeds in upper, middle, and lower layers of areas 3b and 1, we observed strong rsFC between upper and middle layers of these two areas. The layer-resolved activation patterns in areas 3b and 1 agree with their interlayer rsFC patterns, and are consistent with the known anatomical connections between layers. In summary, using BOLD rsFC pattern, we identified an interlayer interareal microcircuit that shows strong intrinsic functional connections between upper and middle layer areas 3b and 1. RsFC can be used as a robust invasive tool to probe interlayer corticocortical microcircuits.
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Affiliation(s)
- Arabinda Mishra
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
| | - Shantanu Majumdar
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
| | - Feng Wang
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
| | - George H. Wilson
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
| | - John C. Gore
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
| | - Li Min Chen
- Department of Radiology and Radiological SciencesVanderbilt University Medical CenterNashvilleTennessee
- Vanderbilt University Institute of Imaging ScienceVanderbilt UniversityNashvilleTennessee
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Almeida-Corrêa S, Czisch M, Wotjak CT. In Vivo Visualization of Active Polysynaptic Circuits With Longitudinal Manganese-Enhanced MRI (MEMRI). Front Neural Circuits 2018; 12:42. [PMID: 29887796 PMCID: PMC5981681 DOI: 10.3389/fncir.2018.00042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 04/30/2018] [Indexed: 12/23/2022] Open
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for in vivo non-invasive whole-brain mapping of neuronal activity. Mn2+ enters active neurons via voltage-gated calcium channels and increases local contrast in T1-weighted images. Given the property of Mn2+ of axonal transport, this technique can also be used for tract tracing after local administration of the contrast agent. However, MEMRI is still not widely employed in basic research due to the lack of a complete description of the Mn2+ dynamics in the brain. Here, we sought to investigate how the activity state of neurons modulates interneuronal Mn2+ transport. To this end, we injected mice with low dose MnCl2 2. (i.p., 20 mg/kg; repeatedly for 8 days) followed by two MEMRI scans at an interval of 1 week without further MnCl2 injections. We assessed changes in T1 contrast intensity before (scan 1) and after (scan 2) partial sensory deprivation (unilateral whisker trimming), while keeping the animals in a sensory enriched environment. After correcting for the general decay in Mn2+ content, whole brain analysis revealed a single cluster with higher signal in scan 1 compared to scan 2: the left barrel cortex corresponding to the right untrimmed whiskers. In the inverse contrast (scan 2 > scan 1), a number of brain structures, including many efferents of the left barrel cortex were observed. These results suggest that continuous neuronal activity elicited by ongoing sensory stimulation accelerates Mn2+ transport from the uptake site to its projection terminals, while the blockage of sensory-input and the resulting decrease in neuronal activity attenuates Mn2+ transport. The description of this critical property of Mn2+ dynamics in the brain allows a better understanding of MEMRI functional mechanisms, which will lead to more carefully designed experiments and clearer interpretation of the results.
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Affiliation(s)
- Suellen Almeida-Corrêa
- Department of Stress Neurobiology & Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Michael Czisch
- Core Unit Neuroimaging, Max Planck Institute of Psychiatry, Munich, Germany
| | - Carsten T Wotjak
- Department of Stress Neurobiology & Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
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20
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Marquardt I, Schneider M, Gulban OF, Ivanov D, Uludağ K. Cortical depth profiles of luminance contrast responses in human V1 and V2 using 7 T fMRI. Hum Brain Mapp 2018; 39:2812-2827. [PMID: 29575494 DOI: 10.1002/hbm.24042] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 01/23/2018] [Accepted: 03/05/2018] [Indexed: 12/31/2022] Open
Abstract
Neural activity in early visual cortex is modulated by luminance contrast. Cortical depth (i.e., laminar) contrast responses have been studied in monkey early visual cortex, but not in humans. In addition to the high spatial resolution needed and the ensuing low signal-to-noise ratio, laminar studies in humans using fMRI are hampered by the strong venous vascular weighting of the fMRI signal. In this study, we measured luminance contrast responses in human V1 and V2 with high-resolution fMRI at 7 T. To account for the effect of intracortical ascending veins, we applied a novel spatial deconvolution model to the fMRI depth profiles. Before spatial deconvolution, the contrast response in V1 showed a slight local maximum at mid cortical depth, whereas V2 exhibited a monotonic signal increase toward the cortical surface. After applying the deconvolution, both V1 and V2 showed a pronounced local maximum at mid cortical depth, with an additional peak in deep grey matter, especially in V1. Moreover, we found a difference in contrast sensitivity between V1 and V2, but no evidence for variations in contrast sensitivity as a function of cortical depth. These findings are in agreement with results obtained in nonhuman primates, but further research will be needed to validate the spatial deconvolution approach.
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Affiliation(s)
- Ingo Marquardt
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Marian Schneider
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Omer Faruk Gulban
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Dimo Ivanov
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Kâmil Uludağ
- Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, The Netherlands
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21
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Linking brain vascular physiology to hemodynamic response in ultra-high field MRI. Neuroimage 2018; 168:279-295. [DOI: 10.1016/j.neuroimage.2017.02.063] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 01/05/2023] Open
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22
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Hyde JS. Autobiography of James S. Hyde. APPLIED MAGNETIC RESONANCE 2017; 48:1103-1147. [PMID: 29962662 PMCID: PMC6022859 DOI: 10.1007/s00723-017-0950-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The papers, book chapters, reviews, and patents by James S. Hyde in the bibliography of this document have been separated into EPR and MRI sections, and within each section by topics. Within each topic, publications are listed chronologically. A brief summary is provided for each patent listed. A few publications and patents that do not fit this schema have been omitted. This list of publications is preceded by a scientific autobiography that focuses on selected topics that are judged to have been of most scientific importance. References to many of the publications and patents in the bibliography are made in the autobiography.
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Affiliation(s)
- James S Hyde
- Department of Biophysics, Medical College of Wisconsin, 8701 Watertown Plan Road, Milwaukee, WI 53226; 414-955-4000; ; ORCID: 0000-0002-3023-1243
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23
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Poplawsky AJ, Fukuda M, Kim SG. Foundations of layer-specific fMRI and investigations of neurophysiological activity in the laminarized neocortex and olfactory bulb of animal models. Neuroimage 2017; 199:718-729. [PMID: 28502845 DOI: 10.1016/j.neuroimage.2017.05.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/02/2017] [Accepted: 05/11/2017] [Indexed: 12/25/2022] Open
Abstract
Laminar organization of neuronal circuits is a recurring feature of how the brain processes information. For instance, different layers compartmentalize different cell types, synaptic activities, and have unique intrinsic and extrinsic connections that serve as units for specialized signal processing. Functional MRI is an invaluable tool to investigate laminar processing in the in vivo human brain, but it measures neuronal activity indirectly by way of the hemodynamic response. Therefore, the accuracy of high-resolution laminar fMRI depends on how precisely it can measure localized microvascular changes nearest to the site of evoked activity. To determine the specificity of fMRI responses to the true neurophysiological responses across layers, the flexibility to invasive procedures in animal models has been necessary. In this review, we will examine different fMRI contrasts and their appropriate uses for layer-specific fMRI, and how localized laminar processing was examined in the neocortex and olfactory bulb. Through collective efforts, it was determined that microvessels, including capillaries, are regulated within single layers and that several endogenous and contrast-enhanced fMRI contrast mechanisms can separate these neural-specific vascular changes from the nonspecific, especially cerebral blood volume-weighted fMRI with intravenous contrast agent injection. We will also propose some open questions that are relevant for the successful implementation of layer-specific fMRI and its potential future directions to study laminar processing when combined with optogenetics.
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Affiliation(s)
- Alexander John Poplawsky
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Mitsuhiro Fukuda
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute of Basic Science, Suwon 440-746, Republic of Korea; Department of Biomedical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea
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Lecrux C, Hamel E. Neuronal networks and mediators of cortical neurovascular coupling responses in normal and altered brain states. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150350. [PMID: 27574304 PMCID: PMC5003852 DOI: 10.1098/rstb.2015.0350] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2016] [Indexed: 12/18/2022] Open
Abstract
Brain imaging techniques that use vascular signals to map changes in neuronal activity, such as blood oxygenation level-dependent functional magnetic resonance imaging, rely on the spatial and temporal coupling between changes in neurophysiology and haemodynamics, known as 'neurovascular coupling (NVC)'. Accordingly, NVC responses, mapped by changes in brain haemodynamics, have been validated for different stimuli under physiological conditions. In the cerebral cortex, the networks of excitatory pyramidal cells and inhibitory interneurons generating the changes in neural activity and the key mediators that signal to the vascular unit have been identified for some incoming afferent pathways. The neural circuits recruited by whisker glutamatergic-, basal forebrain cholinergic- or locus coeruleus noradrenergic pathway stimulation were found to be highly specific and discriminative, particularly when comparing the two modulatory systems to the sensory response. However, it is largely unknown whether or not NVC is still reliable when brain states are altered or in disease conditions. This lack of knowledge is surprising since brain imaging is broadly used in humans and, ultimately, in conditions that deviate from baseline brain function. Using the whisker-to-barrel pathway as a model of NVC, we can interrogate the reliability of NVC under enhanced cholinergic or noradrenergic modulation of cortical circuits that alters brain states.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- C Lecrux
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Quebec, Canada H3A 2B4
| | - E Hamel
- Laboratory of Cerebrovascular Research, Montreal Neurological Institute, McGill University, 3801 University Street, Montréal, Quebec, Canada H3A 2B4
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Lu H, Wang L, Rea WW, Brynildsen JK, Jaime S, Zuo Y, Stein EA, Yang Y. Low- but Not High-Frequency LFP Correlates with Spontaneous BOLD Fluctuations in Rat Whisker Barrel Cortex. Cereb Cortex 2016; 26:683-694. [PMID: 25331598 PMCID: PMC4712799 DOI: 10.1093/cercor/bhu248] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Resting-state magnetic resonance imaging (rsMRI) is thought to reflect ongoing spontaneous brain activity. However, the precise neurophysiological basis of rsMRI signal remains elusive. Converging evidence supports the notion that local field potential (LFP) signal in the high-frequency range correlates with fMRI response evoked by a task (e.g., visual stimulation). It remains uncertain whether this relationship extends to rsMRI. In this study, we systematically modulated LFP signal in the whisker barrel cortex (WBC) by unilateral deflection of rat whiskers. Results show that functional connectivity between bilateral WBC was significantly modulated at the 2 Hz, but not at the 4 or 6 Hz, stimulus condition. Electrophysiologically, only in the low-frequency range (<5 Hz) was the LFP power synchrony in bilateral WBC significantly modulated at 2 Hz, but not at 4- or 6-Hz whisker stimulation, thus distinguishing these 2 experimental conditions, and paralleling the findings in rsMRI. LFP power synchrony in other frequency ranges was modulated in a way that was neither unique to the specific stimulus conditions nor parallel to the fMRI results. Our results support the hypothesis that emphasizes the role of low-frequency LFP signal underlying rsMRI.
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Affiliation(s)
| | | | - William W. Rea
- Neuroimaging Research Branch and
- Integrative Neurobiology Section, National Institute on Drug Abuse, Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | | | - Saul Jaime
- Neuroimaging Research Branch and
- Department of Physiology, School of Medicine, University of Texas Health Science Center in San Antonio, TX 78229, USA
| | - Yantao Zuo
- Neuroimaging Research Branch and
- Psychiatry and Behavioral Sciences, Duke University School of Medicine, Durham, NC 27705, USA
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Hitora-Imamura N, Miura Y, Teshirogi C, Ikegaya Y, Matsuki N, Nomura H. Prefrontal dopamine regulates fear reinstatement through the downregulation of extinction circuits. eLife 2015; 4. [PMID: 26226637 PMCID: PMC4547090 DOI: 10.7554/elife.08274] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 07/29/2015] [Indexed: 12/17/2022] Open
Abstract
Prevention of relapses is a major challenge in treating anxiety disorders. Fear reinstatement can cause relapse in spite of successful fear reduction through extinction-based exposure therapy. By utilising a contextual fear-conditioning task in mice, we found that reinstatement was accompanied by decreased c-Fos expression in the infralimbic cortex (IL) with reduction of synaptic input and enhanced c-Fos expression in the medial subdivision of the central nucleus of the amygdala (CeM). Moreover, we found that IL dopamine plays a key role in reinstatement. A reinstatement-inducing reminder shock induced c-Fos expression in the IL-projecting dopaminergic neurons in the ventral tegmental area, and the blocking of IL D1 signalling prevented reduction of synaptic input, CeM c-Fos expression, and fear reinstatement. These findings demonstrate that a dopamine-dependent inactivation of extinction circuits underlies fear reinstatement and may explain the comorbidity of substance use disorders and anxiety disorders.
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Affiliation(s)
- Natsuko Hitora-Imamura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yuki Miura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Chie Teshirogi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Norio Matsuki
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
| | - Hiroshi Nomura
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, University of Tokyo, Tokyo, Japan
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Suh JY, Shim WH, Cho G, Fan X, Kwon SJ, Kim JK, Dai G, Wang X, Kim YR. Reduced microvascular volume and hemispherically deficient vasoreactivity to hypercapnia in acute ischemia: MRI study using permanent middle cerebral artery occlusion rat model. J Cereb Blood Flow Metab 2015; 35:1033-43. [PMID: 25690471 PMCID: PMC4640250 DOI: 10.1038/jcbfm.2015.22] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 01/11/2015] [Accepted: 01/12/2015] [Indexed: 11/09/2022]
Abstract
Vasoreactivity to hypercapnia has been used for assessing cerebrovascular tone and control altered by ischemic stroke. Despite the high prognostic potential, traits of hypercapnia-induced hemodynamic changes have not been fully characterized in relation with baseline vascular states and brain tissue damage. To monitor cerebrovascular responses, T2- and T2*-weighted magnetic resonance imaging (MRI) images were acquired alternatively using spin- and gradient-echo echo plannar imaging (GESE EPI) sequence with 5% CO2 gas inhalation in normal (n=5) and acute stroke rats (n=10). Dynamic relative changes in cerebrovascular volume (CBV), microvascular volume (MVV), and vascular size index (VSI) were assessed from regions of interest (ROIs) delineated by the percent decrease of apparent diffusion coefficient (ADC). The baseline CBV was not affected by middle cerebral artery occlusion (MCAO) whereas the baseline MVV in ischemic areas was significantly lower than that in the rest of the brain and correlated with ADC. Vasoreactivity to hypercapnic challenge was considerably attenuated in the entire ipsilesional hemisphere including normal ADC regions, in which unsolicited, spreading depression-associated increases of CBV and MVV were observed. The lesion-dependent inhomogeneity in baseline MVV indicates the effective perfusion reserve for accurately delineating the true ischemic damage while the cascade of neuronal depolarization is probably responsible for the hemispherically lateralized changes in overall neurovascular physiology.
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Affiliation(s)
- J Y Suh
- 1] Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, The Republic of Korea
| | - Woo H Shim
- 1] Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, The Republic of Korea
| | - Gyunggoo Cho
- Division of Magnetic Resonance Research, Korea Basic Science Institute, Cheongwon, Chungbuk, The Republic of Korea
| | - Xiang Fan
- Neuroprotection Research Laboratory, Department of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Seon J Kwon
- 1] Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Neurology, Kang's Medical Center, Pocheon, The Republic of Korea
| | - Jeong K Kim
- 1] Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, The Republic of Korea
| | - George Dai
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Xiaoying Wang
- Neuroprotection Research Laboratory, Department of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA
| | - Young R Kim
- 1] Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts, USA [2] School of Nano-Bioscience and Chemical Engineering, UNIST (Ulsan National Institute of Science and Technology), Ulsan, The Republic of Korea
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29
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Abstract
The somatosensory functional magnetic resonance imaging (fMRI) response to electrical stimulation of the middle phalange of the second digit of four rats at a spatial resolution of 200 μm cubic at 9.4 T is reported. At high threshold (p<0.002), activated voxels encompass a penetrating vein that passes across the gray matter. These voxels lie mostly in three contiguous slices perpendicular to the pial surface. This activation is assigned to the representation in the forepaw barrel subfield (FBS) of a single cortical column of this phalange. In addition, the activation of the indusium griseum (IG) is visualized robustly. Voxels revealed by fMRI were used to observe functional connectivity to other voxels of the sensorimotor cortex using fcMRI. Results of this experiment were analyzed as a function of decreasing threshold, which exhibited spreading connectivity that revealed S2, M1/M2, and contralateral S1. Noting that every cubic millimeter of tissue contains 125 voxels, connectivity patterns are complex. It is hypothesized that they reflect connections within gray matter by association fibers. S2 and IG revealed connectivities with many voxels across the sensorimotor cortex. These regions also showed subregional variation of connectivity. A 1-cm-diameter surface coil with a local low-noise RF amplifier was used in these studies. The usual region of sensitivity (ROS) of such a coil is 1 cm diameter by 0.5 cm depth. Significant connectivity was observed between time courses of voxels that were within the ROS and voxels that were outside, which extends the volume of tissue that can be observed by the methods of this article.
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Affiliation(s)
- James S Hyde
- Department of Biophysics, Medical College of Wisconsin , Milwaukee, Wisconsin
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30
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Auffret M, Samim I, Lepore M, Gruetter R, Just N. Quantitative activity-induced manganese-dependent MRI for characterizing cortical layers in the primary somatosensory cortex of the rat. Brain Struct Funct 2014; 221:695-707. [PMID: 25366973 DOI: 10.1007/s00429-014-0933-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 10/24/2014] [Indexed: 11/29/2022]
Abstract
The ability of Mn(2+) to follow Ca(2+) pathways upon stimulation transform them into remarkable surrogate markers of neuronal activity using activity-induced manganese-dependent MRI (AIM-MRI). In the present study, a precise follow-up of physiological parameters during MnCl2 and mannitol infusions improved the reproducibility of AIM-MRI allowing in-depth evaluation of the technique. Pixel-by-pixel T1 data were investigated using histogram distributions in the barrel cortex (BC) and the thalamus before and after Mn(2+) infusion, after blood brain barrier opening and after BC activation. Mean BC T1 values dropped significantly upon trigeminal nerve (TGN) stimulation (-38 %, P = 0.02) in accordance with previous literature findings. T1 histogram distributions showed that 34 % of T1s in the range 600-1500 ms after Mn(2+ )+ mannitol infusions shifted to 50-350 ms after TGN stimulation corresponding to a twofold increase of the percentage of pixels with the lowest T1s in BC. Moreover, T1 changes in response to stimulation increased significantly from superficial cortical layers (I-III) to deeper layers (V-VI). Cortical cytoarchitecture detection during a functional paradigm was performed extending the potential of AIM-MRI. Quantitative AIM-MRI could thus offer a means to interpret local neural activity across cortical layers while identification of the role of calcium dynamics in vivo during brain activation could play a key role in resolving neurovascular coupling mechanisms.
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Affiliation(s)
- Matthieu Auffret
- Laboratory for Functional and Metabolic Imaging (LIFMET), Centre d'Imagerie Biomédicale-Animal Imaging and Technology Core (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - Idrees Samim
- Laboratory for Functional and Metabolic Imaging (LIFMET), Centre d'Imagerie Biomédicale-Animal Imaging and Technology Core (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - Mario Lepore
- Laboratory for Functional and Metabolic Imaging (LIFMET), Centre d'Imagerie Biomédicale-Animal Imaging and Technology Core (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - Rolf Gruetter
- Laboratory for Functional and Metabolic Imaging (LIFMET), Centre d'Imagerie Biomédicale-Animal Imaging and Technology Core (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland
| | - Nathalie Just
- Laboratory for Functional and Metabolic Imaging (LIFMET), Centre d'Imagerie Biomédicale-Animal Imaging and Technology Core (CIBM-AIT), Ecole Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
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31
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Srinivasan VJ, Radhakrishnan H. Optical Coherence Tomography angiography reveals laminar microvascular hemodynamics in the rat somatosensory cortex during activation. Neuroimage 2014; 102 Pt 2:393-406. [PMID: 25111471 DOI: 10.1016/j.neuroimage.2014.08.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 07/28/2014] [Accepted: 08/02/2014] [Indexed: 11/15/2022] Open
Abstract
The BOLD (blood-oxygen-level dependent) fMRI (functional Magnetic Resonance Imaging) signal is shaped, in part, by changes in red blood cell (RBC) content and flow across vascular compartments over time. These complex dynamics have been challenging to characterize directly due to a lack of appropriate imaging modalities. In this study, making use of infrared light scattering from RBCs, depth-resolved Optical Coherence Tomography (OCT) angiography was applied to image laminar functional hyperemia in the rat somatosensory cortex. After defining and validating depth-specific metrics for changes in RBC content and speed, laminar hemodynamic responses in microvasculature up to cortical depths of >1mm were measured during a forepaw stimulus. The results provide a comprehensive picture of when and where changes in RBC content and speed occur during and immediately following cortical activation. In summary, the earliest and largest microvascular RBC content changes occurred in the middle cortical layers, while post-stimulus undershoots were most prominent superficially. These laminar variations in positive and negative responses paralleled known distributions of excitatory and inhibitory synapses, suggesting neuronal underpinnings. Additionally, the RBC speed response consistently returned to baseline more promptly than RBC content after the stimulus across cortical layers, supporting a "flow-volume mismatch" of hemodynamic origin.
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Affiliation(s)
- Vivek J Srinivasan
- Department of Biomedical Engineering, University of California at Davis, 451 E. Health Sciences Dr. GBSF 2303, Davis, CA 95616, USA.
| | - Harsha Radhakrishnan
- Department of Biomedical Engineering, University of California at Davis, 451 E. Health Sciences Dr. GBSF 2303, Davis, CA 95616, USA
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32
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Wu J, Guo C, Chen S, Jiang T, He Y, Ding W, Yang Z, Luo Q, Gong H. Direct 3D Analyses Reveal Barrel-Specific Vascular Distribution and Cross-Barrel Branching in the Mouse Barrel Cortex. Cereb Cortex 2014; 26:23-31. [PMID: 25085882 DOI: 10.1093/cercor/bhu166] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Whether vascular distribution is spatially specific among cortical columns is a fundamental yet controversial question. Here, we have obtained 1-μm resolution 3D datasets that cover the whole mouse barrel cortex by combining Nissl staining with micro-optical sectioning tomography to simultaneously visualize individual cells and blood vessels, including capillaries. Pinpointing layer IV of the posteromedial barrel subfield, direct 3D reconstruction and quantitative analysis showed that (1) penetrating vessels preferentially locate in the interbarrel septa/barrel wall (75.1%) rather than the barrel hollows, (2) the branches of 70% penetrating vessels only reach the neighboring but not always all the neighboring barrels and the other 30% extend beyond the neighboring barrels and may provide cross-barrel blood supply or drainage, (3) the branches of 59.6% penetrating vessels reach all the neighboring barrels, while the rest only reach part of them, and (4) the length density of microvessels in the interbarrel septa/barrel wall is lower than that in the barrel hollows with a ratio of 0.92. These results reveal that the penetrating vessels and microvessels exhibit a barrel-specific organization, whereas the branches of penetrating vessels do not, which suggests a much more complex vascular distribution pattern among cortical columns than previously thought.
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Affiliation(s)
- Jingpeng Wu
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Congdi Guo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shangbin Chen
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Tao Jiang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Yong He
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Wenxiang Ding
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Zhongqin Yang
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Qingming Luo
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Hui Gong
- Britton Chance Center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics.,MoE Key Laboratory for Biomedical Photonics, Department of Biomedical Engineering, Huazhong University of Science and Technology, Wuhan 430074, China
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33
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Chao THH, Chen JH, Yen CT. Repeated BOLD-fMRI imaging of deep brain stimulation responses in rats. PLoS One 2014; 9:e97305. [PMID: 24825464 PMCID: PMC4019572 DOI: 10.1371/journal.pone.0097305] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Accepted: 04/17/2014] [Indexed: 11/18/2022] Open
Abstract
Functional magnetic resonance imaging (fMRI) provides a picture of the global spatial activation pattern of the brain. Interest is growing regarding the application of fMRI to rodent models to investigate adult brain plasticity. To date, most rodent studies used an electrical forepaw stimulation model to acquire fMRI data, with α-chloralose as the anesthetic. However, α-chloralose is harmful to animals, and not suitable for longitudinal studies. Moreover, peripheral stimulation models enable only a limited number of brain regions to be studied. Processing between peripheral regions and the brain is multisynaptic, and renders interpretation difficult and uncertain. In the present study, we combined the medetomidine-based fMRI protocol (a noninvasive rodent fMRI protocol) with chronic implantation of an MRI-compatible stimulation electrode in the ventroposterior (VP) thalamus to repetitively sample thalamocortical responses in the rat brain. Using this model, we scanned the forebrain responses evoked by the VP stimulation repeatedly of individual rats over 1 week. Cortical BOLD responses were compared between the 2 profiles obtained at day1 and day8. We discovered reproducible frequency- and amplitude-dependent BOLD responses in the ipsilateral somatosensory cortex (S1). The S1 BOLD responses during the 2 sessions were conserved in maximal response amplitude, area size (size ratio from 0.88 to 0.91), and location (overlap ratio from 0.61 to 0.67). The present study provides a long-term chronic brain stimulation protocol for studying the plasticity of specific neural circuits in the rodent brain by BOLD-fMRI.
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Affiliation(s)
| | - Jyh-Horng Chen
- Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
| | - Chen-Tung Yen
- Department of Life Science, National Taiwan University, Taipei, Taiwan
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34
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Shih YYI, Yash TV, Rogers B, Duong TQ. FMRI of deep brain stimulation at the rat ventral posteromedial thalamus. Brain Stimul 2013; 7:190-3. [PMID: 24309153 DOI: 10.1016/j.brs.2013.11.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 09/25/2013] [Accepted: 11/01/2013] [Indexed: 10/26/2022] Open
Abstract
BACKGROUND Functional magnetic resonance imaging (fMRI) of deep brain stimulation (DBS) has potentials to reveal neuroanatomical connectivity of a specific brain region in vivo. OBJECTIVE This study aimed to demonstrate frequency and amplitude tunings of the thalamocortical tract using DBS fMRI at the rat ventral posteromedial thalamus. METHODS Blood oxygenation level dependent (BOLD) fMRI data were acquired in a total of twelve rats at a high-field 11.7 T MRI scanner with modulation of nine stimulus frequencies (1-40 Hz) and seven stimulus amplitudes (0.2-3.6 mA). RESULTS BOLD response in the barrel cortex peaked at 25 Hz. The response increased with stimulus amplitude and reached a plateau at 1 mA. Cortical spreading depolarization (CSD) was observed occasionally after DBS that carries >10% BOLD waves spanning the entire ipsilateral cortex. CONCLUSION fMRI is sensitive to the frequency effect of DBS and has potential to investigate the function of a particular neuroanatomical pathway.
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Affiliation(s)
- Yen-Yu Ian Shih
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA; Biomedical Research Imaging Center, University of North Carolina, Chapel Hill, NC 27599, USA; Department of Biomedical Engineering, University of North Carolina, Chapel Hill, NC 27599, USA.
| | - Tiwari V Yash
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; Department of Biomedical Engineering, University of Texas at San Antonio, San Antonio, TX 78249, USA
| | - Bill Rogers
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA
| | - Timothy Q Duong
- Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX 78229, USA; South Texas Veterans Health Care System, Department of Veterans Affairs, USA.
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35
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Lu H, Stein EA. Resting state functional connectivity: its physiological basis and application in neuropharmacology. Neuropharmacology 2013; 84:79-89. [PMID: 24012656 DOI: 10.1016/j.neuropharm.2013.08.023] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 07/14/2013] [Accepted: 08/21/2013] [Indexed: 11/29/2022]
Abstract
Brain structures do not work in isolation; they work in concert to produce sensory perception, motivation and behavior. Systems-level network activity can be investigated by resting state magnetic resonance imaging (rsMRI), an emerging neuroimaging technique that assesses the synchrony of the brain's ongoing spontaneous activity. Converging evidence reveals that rsMRI is able to consistently identify distinct spatiotemporal patterns of large-scale brain networks. Dysregulation within and between these networks has been implicated in a number of neurodegenerative and neuropsychiatric disorders, including Alzheimer's disease and drug addiction. Despite wide application of this approach in systems neuroscience, the physiological basis of these fluctuations remains incompletely understood. Here we review physiological studies in electrical, metabolic and hemodynamic fluctuations that are most pertinent to the rsMRI signal. We also review recent applications to neuropharmacology - specifically drug effects on resting state fluctuations. We speculate that the mechanisms governing spontaneous fluctuations in regional oxygenation availability likely give rise to the observed rsMRI signal. We conclude by identifying several open questions surrounding this technique. This article is part of the Special Issue Section entitled 'Neuroimaging in Neuropharmacology'.
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Affiliation(s)
- Hanbing Lu
- Neuroimaging Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, USA.
| | - Elliot A Stein
- Neuroimaging Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, USA
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36
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Huber L, Ivanov D, Krieger SN, Streicher MN, Mildner T, Poser BA, Möller HE, Turner R. Slab-selective, BOLD-corrected VASO at 7 Tesla provides measures of cerebral blood volume reactivity with high signal-to-noise ratio. Magn Reson Med 2013; 72:137-48. [DOI: 10.1002/mrm.24916] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/04/2013] [Accepted: 07/16/2013] [Indexed: 12/12/2022]
Affiliation(s)
- Laurentius Huber
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Dimo Ivanov
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
- Maastricht Brain Imaging Centre; Maastricht University; Maastricht The Netherlands
| | - Steffen N. Krieger
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
- Monash Biomedical Imaging; Monash University; Melbourne Victoria Australia
| | - Markus N. Streicher
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Toralf Mildner
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Benedikt A. Poser
- Maastricht Brain Imaging Centre; Maastricht University; Maastricht The Netherlands
- Department of Medicine; John A. Burns School of Medicine; University of Hawaii; Honolulu Hawaii USA
- Donders Institute; Centre for Cognitive Neuroimaging; Radboud University Nijmegen; Nijmegen The Netherlands
| | - Harald E. Möller
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
| | - Robert Turner
- Max Planck Institute for Human Cognitive and Brain Sciences; Leipzig Germany
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37
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Kim SG, Harel N, Jin T, Kim T, Lee P, Zhao F. Cerebral blood volume MRI with intravascular superparamagnetic iron oxide nanoparticles. NMR IN BIOMEDICINE 2013; 26. [PMID: 23208650 PMCID: PMC3700592 DOI: 10.1002/nbm.2885] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The cerebral blood volume (CBV) is a crucial physiological indicator of tissue viability and vascular reactivity. Thus, noninvasive CBV mapping has been of great interest. For this, ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles, including monocrystalline iron oxide nanoparticles, can be used as long-half-life, intravascular susceptibility agents of CBV MRI measurements. Moreover, CBV-weighted functional MRI (fMRI) with USPIO nanoparticles provides enhanced sensitivity, reduced large vessel contribution and improved spatial specificity relative to conventional blood oxygenation level-dependent fMRI, and measures a single physiological parameter that is easily interpretable. We review the physiochemical and magnetic properties, and pharmacokinetics, of USPIO nanoparticles in brief. We then extensively discuss quantifications of baseline CBV, vessel size index and functional CBV change. We also provide reviews of dose-dependent sensitivity, vascular filter function, specificity, characteristics and impulse response function of CBV fMRI. Examples of CBV fMRI specificity at the laminar and columnar resolution are provided. Finally, we briefly review the application of CBV measurements to functional and pharmacological studies in animals. Overall, the use of USPIO nanoparticles can determine baseline CBV and its changes induced by functional activity and pharmacological interventions.
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Affiliation(s)
- Seong-Gi Kim
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, PA, USA.
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38
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Shih YYI, Chen YY, Lai HY, Kao YCJ, Shyu BC, Duong TQ. Ultra high-resolution fMRI and electrophysiology of the rat primary somatosensory cortex. Neuroimage 2013; 73:113-20. [PMID: 23384528 DOI: 10.1016/j.neuroimage.2013.01.062] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 01/16/2013] [Accepted: 01/28/2013] [Indexed: 11/29/2022] Open
Abstract
High-resolution functional-magnetic-resonance-imaging (fMRI) has been used to study brain functions at increasingly finer scale, but whether fMRI can accurately reflect layer-specific neuronal activities is less well understood. The present study investigated layer-specific cerebral-blood-volume (CBV) fMRI and electrophysiological responses in the rat cortex. CBV fMRI at 40×40 μm in-plane resolution was performed on an 11.7-T scanner. Electrophysiology used a 32-channel electrode array that spanned the entire cortical depth. Graded electrical stimulation was used to study activations in different cortical layers, exploiting the notion that most of the sensory-specific neurons are in layers II-V and most of the nociceptive-specific neurons are in layers V-VI. CBV response was strongest in layer IV of all stimulus amplitudes. Current source density analysis showed strong sink currents at cortical layers IV and VI. Multi-unit activities mainly appeared at layers IV-VI and peaked at layer V. Although our measures showed scaled activation profiles during modulation of stimulus amplitude and failed to detect specific recruitment at layers V and VI during noxious electrical stimuli, there appears to be discordance between CBV fMRI and electrophysiological peak responses, suggesting neurovascular uncoupling at laminar resolution. The technique implemented in the present study offers a means to investigate intracortical neurovascular function in the normal and diseased animal models at laminar resolution.
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Affiliation(s)
- Yen-Yu Ian Shih
- Department of Neurology, University of North Carolina, Chapel Hill, NC 27599, USA.
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39
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Lindvere L, Janik R, Dorr A, Chartash D, Sahota B, Sled JG, Stefanovic B. Cerebral microvascular network geometry changes in response to functional stimulation. Neuroimage 2013; 71:248-59. [PMID: 23353600 DOI: 10.1016/j.neuroimage.2013.01.011] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 01/02/2013] [Accepted: 01/08/2013] [Indexed: 01/28/2023] Open
Abstract
The cortical microvessels are organized in an intricate, hierarchical, three-dimensional network. Superimposed on this anatomical complexity is the highly complicated signaling that drives the focal blood flow adjustments following a rise in the activity of surrounding neurons. The microvascular response to neuronal activation remains incompletely understood. We developed a custom two photon fluorescence microscopy acquisition and analysis to obtain 3D maps of neuronal activation-induced changes in the geometry of the microvascular network of the primary somatosensory cortex of anesthetized rats. An automated, model-based tracking algorithm was employed to reconstruct the 3D microvascular topology and represent it as a graph. The changes in the geometry of this network were then tracked, over time, in the course of electrical stimulation of the contralateral forepaw. Both dilatory and constrictory responses were observed across the network. Early dilatory and late constrictory responses propagated from deeper to more superficial cortical layers while the response of the vertices that showed initial constriction followed by later dilation spread from cortical surface toward increasing cortical depths. Overall, larger caliber adjustments were observed deeper inside the cortex. This work yields the first characterization of the spatiotemporal pattern of geometric changes on the level of the cortical microvascular network as a whole and provides the basis for bottom-up modeling of the hemodynamically-weighted neuroimaging signals.
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Affiliation(s)
- Liis Lindvere
- Imaging Research, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON, Canada M4N 3M5
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40
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Bonab AA, Fricchione JG, Gorantla S, Vitalo AG, Auster ME, Levine SJ, Scichilone JM, Hegde M, Foote W, Fricchione GL, Denninger JW, Yarmush DM, Fischman AJ, Yarmush ML, Levine JB. Isolation rearing significantly perturbs brain metabolism in the thalamus and hippocampus. Neuroscience 2012; 223:457-64. [PMID: 22835621 DOI: 10.1016/j.neuroscience.2012.07.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 07/16/2012] [Accepted: 07/17/2012] [Indexed: 01/04/2023]
Abstract
Psychosocial neglect during childhood severely impairs both behavioral and physical health. The isolation rearing model in rodents has been employed by our group and others to study this clinical problem at a basic level. We previously showed that immediate early gene (IEG) expression in the hippocampus and medial prefrontal cortex (mPFC) is decreased in isolation-reared (IR) compared to group-reared (GR) rats. In the current study, we sought to evaluate: (1) whether these changes in IEG expression would be detected by the measurement of brain glucose metabolism using positron emission tomography (PET) with fluorodeoxyglucose (FDG) and (2) whether PET FDG could illuminate other brain regions with different glucose metabolism in IR compared to GR rats. We found that there were significant differences in FDG uptake in the hippocampus that were consistent with our findings for IEG expression (decreased mean FDG uptake in IR rats). In contrast, in the mPFC, the FDG uptake between IR and GR rats did not differ. Finally, we found decreased mean FDG uptake in the thalamus of the IR rats, a region we had not previously examined. The results suggest that PET FDG has the potential to be utilized as a biomarker of molecular changes in the hippocampus. Further, the differences found in thalamic brain FDG uptake suggest that further investigation of this region at the molecular and cellular levels may provide an important insight into the neurobiological basis of the adverse clinical outcomes found in children exposed to psychosocial deprivation.
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Affiliation(s)
- A A Bonab
- Department of Nuclear Medicine, Massachusetts General Hospital, United States
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41
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Qiu D, Zaharchuk G, Christen T, Ni WW, Moseley ME. Contrast-enhanced functional blood volume imaging (CE-fBVI): enhanced sensitivity for brain activation in humans using the ultrasmall superparamagnetic iron oxide agent ferumoxytol. Neuroimage 2012; 62:1726-31. [PMID: 22584230 DOI: 10.1016/j.neuroimage.2012.05.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/05/2012] [Accepted: 05/04/2012] [Indexed: 11/25/2022] Open
Abstract
Functional MRI (fMRI) brain studies performed in the presence of a steady-state or "blood pool" contrast agent yields activation maps that are weighted for cerebral blood volume (CBV). Previous animal experiments suggest significant contrast-to-noise ratio (CNR) improvements, but these studies have not yet been performed in humans due to the lack of availability of a suitable agent. Here we report the use of the USPIO ferumoxytol (AMAG Pharmaceuticals, Inc., Cambridge, MA) for functional brain activation in humans, termed contrast enhanced functional blood volume imaging (CE-fBVI). Four subjects were scanned during a unilateral finger tapping task with standard blood-oxygen level dependent (BOLD) imaging before contrast and CE-fBVI after contrast injection. The CE-fBVI response showed both a fast (5.8±1.3 s) and a slow (75.3±27.5 s) component of CBV response to stimuli. A significant CNR gain of approximately 2-3 was found for CE-fBVI compared to BOLD fMRI. Interestingly, less susceptibility-related signal dropouts were observed in the inferior frontal and temporal lobes with CE-fBVI. The combination of higher CNR and better spatial specificity, enabled by CE-fBVI using blood pool USPIO contrast agent opens the door to higher resolution brain mapping.
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Affiliation(s)
- Deqiang Qiu
- Department of Radiology, Stanford University, CA, USA.
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42
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Krueger G, Granziera C. The history and role of long duration stimulation in fMRI. Neuroimage 2012; 62:1051-5. [PMID: 22281678 DOI: 10.1016/j.neuroimage.2012.01.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Revised: 01/04/2012] [Accepted: 01/05/2012] [Indexed: 12/31/2022] Open
Abstract
During the past 20 years, BOLD fMRI has developed towards a central and fundamental tool in neuroscience. It has been shown that the BOLD response provides an indicator of neuronal activity in the brain. Consequently, for an accurate interpretation of findings in BOLD MRI experiments and to draw meaningful conclusions about the temporal evolution of neural events, a deep understanding of the nature of the BOLD contrast has become of essential importance. Since the dynamics of the major direct determinants of the BOLD signal (CBF, CBV and CMRO(2)) range between seconds and minutes, long duration stimulation was an early key strategy needed to study and understand the BOLD characteristics. This paper summarizes and discusses the thoughts and rationales of the long duration stimulation studies.
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Affiliation(s)
- Gunnar Krueger
- Siemens Schweiz AG, Healthcare Sector IM&WS S, Renens, Switzerland.
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43
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Neuronal inhibition and excitation, and the dichotomic control of brain hemodynamic and oxygen responses. Neuroimage 2012; 62:1040-50. [PMID: 22261372 DOI: 10.1016/j.neuroimage.2012.01.040] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 12/27/2011] [Accepted: 01/01/2012] [Indexed: 12/30/2022] Open
Abstract
Brain's electrical activity correlates strongly to changes in cerebral blood flow (CBF) and the cerebral metabolic rate of oxygen (CMRO(2)). Subthreshold synaptic processes correlate better than the spike rates of principal neurons to CBF, CMRO(2) and positive BOLD signals. Stimulation-induced rises in CMRO(2) are controlled by the ATP turnover, which depends on the energy used to fuel the Na,K-ATPase to reestablish ionic gradients, while stimulation-induced CBF responses to a large extent are controlled by mechanisms that depend on Ca(2+) rises in neurons and astrocytes. This dichotomy of metabolic and vascular control explains the gap between the stimulation-induced rises in CMRO(2) and CBF, and in turn the BOLD signal. Activity-dependent rises in CBF and CMRO(2) vary within and between brain regions due to differences in ATP turnover and Ca(2+)-dependent mechanisms. Nerve cells produce and release vasodilators that evoke positive BOLD signals, while the mechanisms that control negative BOLD signals by activity-dependent vasoconstriction are less well understood. Activation of both excitatory and inhibitory neurons produces rises in CBF and positive BOLD signals, while negative BOLD signals under most conditions correlate to excitation of inhibitory interneurons, but there are important exceptions to that rule as described in this paper. Thus, variations in the balance between synaptic excitation and inhibition contribute dynamically to the control of metabolic and hemodynamic responses, and in turn the amplitude and polarity of the BOLD signal. Therefore, it is not possible based on a negative or positive BOLD signal alone to decide whether the underlying activity goes on in principal or inhibitory neurons.
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Zuo Y, Lu H, Vaupel DB, Zhang Y, Chefer SI, Rea WR, Moore AV, Yang Y, Stein EA. Acute nicotine-induced tachyphylaxis is differentially manifest in the limbic system. Neuropsychopharmacology 2011; 36:2498-512. [PMID: 21796109 PMCID: PMC3194077 DOI: 10.1038/npp.2011.139] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rapid tolerance develops to many of nicotine's behavioral and autonomic effects. A better understanding of the spatiotemporal patterns in neuronal activity as a consequence of acute nicotine tolerance (tachyphylaxis) may help explain its commonly found inverted 'U'-shaped biphasic dose-effect relationship on various behaviors. To this end, we employed high-resolution functional magnetic resonance imaging and relative cerebral blood volume (rCBV) as a marker of neuronal activity, to characterize the regional development of acute tolerance as a function of nicotine dose in naïve, anesthetized rats. A single intravenous nicotine injection at 0.1 and 0.3, but not 0.03 mg/kg, significantly increased neuronal activity in many neocortical areas. In contrast, dose-dependent increases in rCBV were most pronounced in limbic regions, such that responses seen at 0.1 mg/kg nicotine in accumbens, hippocampus, amygdala, and several other limbic areas were not seen following 0.3 mg/kg nicotine. Finally, whereas profound tolerance was observed in many cortical regions after the second of two paired nicotine injections at either 0.1 or 0.3 mg/kg, subcortical limbic structures showed only a weak trend for tolerance. Lack of rCBV changes in animals receiving nicotine methiodide, a quaternary nicotine analog that does not cross the blood-brain barrier, supports a direct neuronal effect of nicotine rather than an action on the vasculature. These data provide pharmacodynamic insight into the regional heterogeneity of nicotine tachyphylaxis development, which may be relevant to behavioral and neurobiological mechanisms associated with repeated tobacco consumption.
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Affiliation(s)
- Yantao Zuo
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - Hanbing Lu
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - D Bruce Vaupel
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - Yi Zhang
- National Institute on Mental Health, Bethesda, MD, USA
| | - Svetlana I Chefer
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - William R Rea
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - Anna V Moore
- Molecular Imaging Laboratory, Department of Radiology, MGH/MIT/HMS Athinoula A Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA
| | - Yihong Yang
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA
| | - Elliot A Stein
- Neuroimaging Research Branch, National Institute on Drug Abuse, Intramural Research Program, Baltimore, MD, USA,National Institute on Drug Abuse Intramural Research Program (NIDA IRP), Neuroimaging Research Branch, 251 Bayview Boulevard, Suite 200, Room 7A711A, Baltimore, MD 21224, USA. Tel: +1 443 740 2650; Fax: +1 443 740 2734; E-mail:
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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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Kannurpatti SS, Biswal BB. Frequency tuning in the rat whisker barrel cortex revealed through RBC flux maps. Brain Res 2011; 1417:16-26. [PMID: 21911212 DOI: 10.1016/j.brainres.2011.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 07/29/2011] [Accepted: 08/10/2011] [Indexed: 11/25/2022]
Abstract
The rodent whisker barrel cortex is ideal for studies related to sensory processing and neural plasticity in the brain. However, its small spatial dimensions challenge optical and other imaging technologies mapping cortical hemodynamics as functional resolution (the ability to spatially and selectively discriminate signals from microvascular compartments) limit measurement accuracy. To precisely map hemodynamic activity within the rat posteriomedial barrel subfield (PMBSF), we used functional Laser Doppler Imaging (fLDI) at high spatial resolution with optimized detection and analysis. In this configuration, we demonstrate prominent whisker deflection-induced fLDI hemodynamic responses from microvascular regions indicating the technique's specificity to smaller vessel compartments. Clusters of fLDI activation were confined within the PMBSF region during deflection of either single or all whiskers. Stereotaxic co-ordinate mapping was performed over all animals leading to an average maximum activity cluster at +5.3, -3.5 from the Bregma. The maximum activity cluster during all whisker stimulation combined with the principal activation cluster during deflection of the C1 whisker were used as a reference to characterize the fLDI maps within the PMBSF. fLDI activation area increased with the frequency of whisker deflection. In a quantitative analysis, we reveal the increase in the spatial extent of fLDI activation with stimulation frequency as spatially non-uniform with a bias towards the caudal region for low and rostral region for higher stimulation frequencies.
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Yu X, Glen D, Wang S, Dodd S, Hirano Y, Saad Z, Reynolds R, Silva AC, Koretsky AP. Direct imaging of macrovascular and microvascular contributions to BOLD fMRI in layers IV-V of the rat whisker-barrel cortex. Neuroimage 2011; 59:1451-60. [PMID: 21851857 DOI: 10.1016/j.neuroimage.2011.08.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Revised: 07/05/2011] [Accepted: 08/02/2011] [Indexed: 02/03/2023] Open
Abstract
The spatiotemporal characteristics of the hemodynamic response to increased neural activity were investigated at the level of individual intracortical vessels using BOLD-fMRI in a well-established rodent model of somatosensory stimulation at 11.7 T. Functional maps of the rat barrel cortex were obtained at 150 × 150 × 500 μm spatial resolution every 200 ms. The high spatial resolution allowed separation of active voxels into those containing intracortical macro vessels, mainly vein/venules (referred to as macrovasculature), and those enriched with arteries/capillaries and small venules (referred to as microvasculature) since the macro vessel can be readily mapped due to the fast T2 decay of blood at 11.7 T. The earliest BOLD response was observed within layers IV-V by 0.8s following stimulation and encompassed mainly the voxels containing the microvasculature and some confined macrovasculature voxels. By 1.2s, the BOLD signal propagated to the macrovasculature voxels where the peak BOLD signal was 2-3 times higher than that of the microvasculature voxels. The BOLD response propagated in individual venules/veins far from neuronal sources at later times. This was also observed in layers IV-V of the barrel cortex after specific stimulation of separated whisker rows. These results directly visualized that the earliest hemodynamic changes to increased neural activity occur mainly in the microvasculature and spread toward the macrovasculature. However, at peak response, the BOLD signal is dominated by penetrating venules even at layers IV-V of the cortex.
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Affiliation(s)
- Xin Yu
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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Koopmans PJ, Barth M, Orzada S, Norris DG. Multi-echo fMRI of the cortical laminae in humans at 7T. Neuroimage 2011; 56:1276-85. [DOI: 10.1016/j.neuroimage.2011.02.042] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Revised: 01/27/2011] [Accepted: 02/12/2011] [Indexed: 01/04/2023] Open
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Abstract
Modifications in the behavior and architecture of neuronal networks are well documented to occur in association with learning and memory, as well as following injury. These plasticity mechanisms are crucial to ensure adequate processing of stimuli, and they also dictate the degree of recovery following peripheral or central nervous system injury. Nevertheless, the underlying neuronal mechanisms that determine the degree of plasticity of neuronal pathways are not fully understood. Recent developments in animal-dedicated magnetic resonance imaging (MRI) scanners and related hardware afford a high spatial and temporal resolution, making functional MRI and manganese-enhanced MRI emerging tools for studying reorganization of neuronal pathways in rodent models. Many of the observed changes in neuronal functions in rodent's brains following injury discussed here agree with clinical human fMRI findings. This demonstrates that animal model imaging can have a significant clinical impact in the neuronal plasticity and rehabilitation arenas.
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Affiliation(s)
- Galit Pelled
- Department of Radiology, Kennedy Krieger Institute, Johns Hopkins School of Medicine, Baltimore, MD, USA.
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Temporal dynamics and spatial specificity of arterial and venous blood volume changes during visual stimulation: implication for BOLD quantification. J Cereb Blood Flow Metab 2011; 31:1211-22. [PMID: 21179068 PMCID: PMC3099637 DOI: 10.1038/jcbfm.2010.226] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Determination of compartment-specific cerebral blood volume (CBV) changes is important for understanding neurovascular physiology and quantifying blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI). In isoflurane-anesthetized cats, we measured the spatiotemporal responses of arterial CBV (CBV(a)) and total CBV (CBV(t)) induced by a 40-second visual stimulation, using magnetization transfer (MT)-varied BOLD and contrast-agent fMRI techniques at 9.4 T. To determine the venous CBV (CBV(v)) change, we calculated the difference between CBV(t) and CBV(a) changes. The dynamic response of CBV(a) was an order of magnitude faster than that of CBV(v), while the magnitude of change under steady-state conditions was similar between the two. Following stimulation offset, ΔCBV(a) showed small poststimulus undershoots, while ΔCBV(v) slowly returned to baseline. The largest CBV(a) and CBV(t) response occurred after 10 seconds of simulation in cortical layer 4, which we identified as the stripe of Gennari by T(1)-weighted MRI. The CBV(v) response, however, was not specific across the cortical layers during the entire stimulation period. Our data indicate that rapid, more-specific arterial vasodilation is followed by slow, less-specific venous dilation. Our finding implies that the contribution of CBV(v) changes to BOLD signals is significant for long, but not short, stimulation periods.
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