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Yu P, Dong R, Wang X, Tang Y, Liu Y, Wang C, Zhao L. Neuroimaging of motor recovery after ischemic stroke - functional reorganization of motor network. Neuroimage Clin 2024; 43:103636. [PMID: 38950504 PMCID: PMC11267109 DOI: 10.1016/j.nicl.2024.103636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 06/01/2024] [Accepted: 06/27/2024] [Indexed: 07/03/2024]
Abstract
The long-term motor outcome of acute stroke patients may be correlated to the reorganization of brain motor network. Abundant neuroimaging studies contribute to understand the pathological changes and recovery of motor networks after stroke. In this review, we summarized how current neuroimaging studies have increased understanding of reorganization and plasticity in post stroke motor recovery. Firstly, we discussed the changes in the motor network over time during the motor-activation and resting states, as well as the overall functional integration trend of the motor network. These studies indicate that the motor network undergoes dynamic bilateral hemispheric functional reorganization, as well as a trend towards network randomization. In the second part, we summarized the current study progress in the application of neuroimaging technology to early predict the post-stroke motor outcome. In the third part, we discuss the neuroimaging techniques commonly used in the post-stroke recovery. These methods provide direct or indirect visualization patterns to understand the neural mechanisms of post-stroke motor recovery, opening up new avenues for studying spontaneous and treatment-induced recovery and plasticity after stroke.
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Affiliation(s)
- Pei Yu
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Ruoyu Dong
- Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Beijing, China
| | - Xiao Wang
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yuqi Tang
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Yaning Liu
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Can Wang
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China
| | - Ling Zhao
- School of Acupuncture and Massage, Chengdu University of Traditional Chinese Medicine, Chengdu, Sichuan, China.
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Sunil S, Jiang J, Shah S, Kura S, Kilic K, Erdener SE, Ayata C, Devor A, Boas DA. Neurovascular coupling is preserved in chronic stroke recovery after targeted photothrombosis. Neuroimage Clin 2023; 38:103377. [PMID: 36948140 PMCID: PMC10034641 DOI: 10.1016/j.nicl.2023.103377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/17/2023]
Abstract
Functional neuroimaging, which measures hemodynamic responses to brain activity, has great potential for monitoring recovery in stroke patients and guiding rehabilitation during recovery. However, hemodynamic responses after stroke are almost always altered relative to responses in healthy subjects and it is still unclear if these alterations reflect the underlying brain physiology or if the alterations are purely due to vascular injury. In other words, we do not know the effect of stroke on neurovascular coupling and are therefore limited in our ability to use functional neuroimaging to accurately interpret stroke pathophysiology. To address this challenge, we simultaneously captured neural activity, through fluorescence calcium imaging, and hemodynamics, through intrinsic optical signal imaging, during longitudinal stroke recovery. Our data suggest that neurovascular coupling was preserved in the chronic phase of recovery (2 weeks and 4 weeks post-stoke) and resembled pre-stroke neurovascular coupling. This indicates that functional neuroimaging faithfully represents the underlying neural activity in chronic stroke. Further, neurovascular coupling in the sub-acute phase of stroke recovery was predictive of long-term behavioral outcomes. Stroke also resulted in increases in global brain oscillations, which showed distinct patterns between neural activity and hemodynamics. Increased neural excitability in the contralesional hemisphere was associated with increased contralesional intrahemispheric connectivity. Additionally, sub-acute increases in hemodynamic oscillations were associated with improved sensorimotor outcomes. Collectively, these results support the use of hemodynamic measures of brain activity post-stroke for predicting functional and behavioral outcomes.
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Affiliation(s)
- Smrithi Sunil
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - John Jiang
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Shashwat Shah
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sreekanth Kura
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kivilcim Kilic
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sefik Evren Erdener
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Cenk Ayata
- Departments of Neurology and Radiology, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Anna Devor
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA 02114, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
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Li R, Mukadam N, Kiran S. Functional MRI evidence for reorganization of language networks after stroke. HANDBOOK OF CLINICAL NEUROLOGY 2022; 185:131-150. [PMID: 35078595 DOI: 10.1016/b978-0-12-823384-9.00007-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this chapter, we review fMRI evidence for language reorganization in individuals with poststroke aphasia. Several studies in the current literature have utilized fMRI as a tool to understand patterns of functional reorganization in poststroke aphasia. Consistent with previous models that have been proposed to explain the trajectory of language recovery, differential patterns of language processing and language recovery have been identified across individuals with poststroke aphasia in different stages of recovery. Overall, a global network breakdown typically occurs in the early stages of aphasia recovery, followed by normalization in "traditional" left hemisphere language networks. Depending on individual characteristics, right hemisphere regions and bilateral domain-general regions may be further recruited. The main takeaway of this chapter is that poststroke aphasia recovery does not depend on individual neural regions, but rather involves a complex interaction among regions in larger networks. Many of the unresolved issues and contrastive findings in the literature warrant further research with larger groups of participants and standard protocols of fMRI implementation.
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Affiliation(s)
- Ran Li
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Nishaat Mukadam
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States
| | - Swathi Kiran
- Department of Speech, Language and Hearing Sciences, Boston University, Boston, MA, United States.
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Cheng HJ, Ng KK, Qian X, Ji F, Lu ZK, Teo WP, Hong X, Nasrallah FA, Ang KK, Chuang KH, Guan C, Yu H, Chew E, Zhou JH. Task-related brain functional network reconfigurations relate to motor recovery in chronic subcortical stroke. Sci Rep 2021; 11:8442. [PMID: 33875691 PMCID: PMC8055891 DOI: 10.1038/s41598-021-87789-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 01/27/2021] [Indexed: 12/12/2022] Open
Abstract
Stroke leads to both regional brain functional disruptions and network reorganization. However, how brain functional networks reconfigure as task demand increases in stroke patients and whether such reorganization at baseline would facilitate post-stroke motor recovery are largely unknown. To address this gap, brain functional connectivity (FC) were examined at rest and motor tasks in eighteen chronic subcortical stroke patients and eleven age-matched healthy controls. Stroke patients underwent a 2-week intervention using a motor imagery-assisted brain computer interface-based (MI-BCI) training with or without transcranial direct current stimulation (tDCS). Motor recovery was determined by calculating the changes of the upper extremity component of the Fugl-Meyer Assessment (FMA) score between pre- and post-intervention divided by the pre-intervention FMA score. The results suggested that as task demand increased (i.e., from resting to passive unaffected hand gripping and to active affected hand gripping), patients showed greater FC disruptions in cognitive networks including the default and dorsal attention networks. Compared to controls, patients had lower task-related spatial similarity in the somatomotor-subcortical, default-somatomotor, salience/ventral attention-subcortical and subcortical-subcortical connections, suggesting greater inefficiency in motor execution. Importantly, higher baseline network-specific FC strength (e.g., dorsal attention and somatomotor) and more efficient brain network reconfigurations (e.g., somatomotor and subcortical) from rest to active affected hand gripping at baseline were related to better future motor recovery. Our findings underscore the importance of studying functional network reorganization during task-free and task conditions for motor recovery prediction in stroke.
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Affiliation(s)
- Hsiao-Ju Cheng
- Center for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore
| | - Kwun Kei Ng
- Center for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Xing Qian
- Center for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Fang Ji
- Center for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Zhong Kang Lu
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore
| | - Wei Peng Teo
- National Institute of Education, Nanyang Technological University, Singapore, Singapore
| | - Xin Hong
- Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore, Singapore
| | - Fatima Ali Nasrallah
- Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore, Singapore
- Queensland Brain Institute and Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
| | - Kai Keng Ang
- Institute for Infocomm Research, Agency for Science Technology and Research, Singapore, Singapore
- School of Computer Science and Engineering, Nanyang Technology University, Singapore, Singapore
| | - Kai-Hsiang Chuang
- Singapore Bioimaging Consortium, Agency for Science Technology and Research, Singapore, Singapore
- Queensland Brain Institute and Centre for Advanced Imaging, The University of Queensland, Brisbane, Australia
| | - Cuntai Guan
- School of Computer Science and Engineering, Nanyang Technology University, Singapore, Singapore
| | - Haoyong Yu
- Department of Biomedical Engineering, Faculty of Engineering, National University of Singapore, Singapore, Singapore
| | - Effie Chew
- Division of Neurology/Rehabilitation Medicine, National University Hospital, Singapore, Singapore.
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, NUHS Tower Block, Level 11, Singapore, 119228, Singapore.
| | - Juan Helen Zhou
- Center for Sleep and Cognition, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Center for Translational Magnetic Resonance Research, Yong Loo Lin School of Medicine, National University of Singapore, Tahir Foundation Building (MD1), 12 Science Drive 2, #13-05C, Singapore, 117549, Singapore.
- Department of Electrical and Computer Engineering, National University of Singapore, Singapore, Singapore.
- Integrative Sciences and Engineering Programme (ISEP), National University of Singapore, Singapore, Singapore.
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Prolonged deficit of low gamma oscillations in the peri-infarct cortex of mice after stroke. Exp Neurol 2021; 341:113696. [PMID: 33727098 DOI: 10.1016/j.expneurol.2021.113696] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 03/04/2021] [Accepted: 03/11/2021] [Indexed: 02/06/2023]
Abstract
Days and weeks after an ischemic stroke, the peri-infarct area adjacent to the necrotic tissue exhibits very intense synaptic reorganization aimed at regaining lost functions. In order to enhance functional recovery, it is important to understand the mechanisms supporting neural repair and neuroplasticity in the cortex surrounding the lesion. Brain oscillations of the local field potential (LFP) are rhythmic fluctuations of neuronal excitability that synchronize neuronal activity to organize information processing and plasticity. Although the oscillatory activity of the brain has been probed after stroke in both animals and humans using electroencephalography (EEG), the latter is ineffective to precisely map the oscillatory changes in the peri-infarct zone where synaptic plasticity potential is high. Here, we worked on the hypothesis that the brain oscillatory system is altered in the surviving peri-infarct cortex, which may slow down the functional repair and reduce the recovery. In order to document the relevance of this hypothesis, oscillatory power was measured at various distances from the necrotic core at 7 and 21 days after a permanent cortical ischemia induced in mice. Delta and theta oscillations remained at a normal power in the peri-infarct cortex, in contrast to low gamma oscillations that displayed a gradual decrease, when approaching the border of the lesion. A broadband increase of power was also observed in the homotopic contralateral sites. Thus, the proximal peri-infarct cortex could become a target of therapeutic interventions applied to correct the oscillatory regimen in order to boost post-stroke functional recovery.
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Sleight E, Stringer MS, Marshall I, Wardlaw JM, Thrippleton MJ. Cerebrovascular Reactivity Measurement Using Magnetic Resonance Imaging: A Systematic Review. Front Physiol 2021; 12:643468. [PMID: 33716793 PMCID: PMC7947694 DOI: 10.3389/fphys.2021.643468] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 02/01/2021] [Indexed: 12/27/2022] Open
Abstract
Cerebrovascular reactivity (CVR) magnetic resonance imaging (MRI) probes cerebral haemodynamic changes in response to a vasodilatory stimulus. CVR closely relates to the health of the vasculature and is therefore a key parameter for studying cerebrovascular diseases such as stroke, small vessel disease and dementias. MRI allows in vivo measurement of CVR but several different methods have been presented in the literature, differing in pulse sequence, hardware requirements, stimulus and image processing technique. We systematically reviewed publications measuring CVR using MRI up to June 2020, identifying 235 relevant papers. We summarised the acquisition methods, experimental parameters, hardware and CVR quantification approaches used, clinical populations investigated, and corresponding summary CVR measures. CVR was investigated in many pathologies such as steno-occlusive diseases, dementia and small vessel disease and is generally lower in patients than in healthy controls. Blood oxygen level dependent (BOLD) acquisitions with fixed inspired CO2 gas or end-tidal CO2 forcing stimulus are the most commonly used methods. General linear modelling of the MRI signal with end-tidal CO2 as the regressor is the most frequently used method to compute CVR. Our survey of CVR measurement approaches and applications will help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.
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Affiliation(s)
- Emilie Sleight
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael S. Stringer
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom,*Correspondence: Michael S. Stringer
| | - Ian Marshall
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Joanna M. Wardlaw
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
| | - Michael J. Thrippleton
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom,UK Dementia Research Institute, Edinburgh, United Kingdom
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Sunil S, Evren Erdener S, Cheng X, Kura S, Tang J, Jiang J, Karrobi K, Kılıç K, Roblyer D, Boas DA. Stroke core revealed by tissue scattering using spatial frequency domain imaging. NEUROIMAGE-CLINICAL 2020; 29:102539. [PMID: 33385882 PMCID: PMC7779322 DOI: 10.1016/j.nicl.2020.102539] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 12/14/2020] [Accepted: 12/15/2020] [Indexed: 12/26/2022]
Abstract
We present OCT and SFDI as methods to measure the spatial extent of stroke in mice. OCT was a reliable predictor of the stroke core in a photothrombosis stroke model. SFDI scattering coefficient spatially overlaps with OCT attenuation after stroke. Scattering increases following stroke reliably predict ischemic injury. SFDI provides a wide-field optical approach to map the stroke core.
Ischemic stroke leads to a reduction or complete loss of blood supply causing injury to brain tissue, which ultimately leads to behavioral impairment. Optical techniques are widely used to study the structural and functional changes that result as a consequence of ischemic stroke both in the acute and chronic phases of stroke recovery. It is currently a challenge to accurately estimate the spatial extent of the infarct without the use of histological parameters however, and in order to follow recovery mechanisms longitudinally at the mesoscopic scale it is essential to know the spatial extent of the stroke core. In this paper we first establish optical coherence tomography (OCT) as a reliable indicator of the stroke core by analyzing signal attenuation and spatially correlating it with the infarct, determined by staining with triphenyl-tetrazolium chloride (TTC). We then introduce spatial frequency domain imaging (SFDI) as a mesoscopic optical technique that can be used to accurately measure the infarct spatial extent by exploiting changes in optical scattering that occur as a consequence of ischemic stroke. Additionally, we follow the progression of ischemia through the acute and sub-acute phases of stroke recovery using both OCT and SFDI and show a consistently high spatial overlap in estimating infarct location. The use of SFDI in assessing infarct location will allow longitudinal studies targeted at following functional recovery mechanisms on a mesoscopic level without having to sacrifice the mouse acutely.
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Affiliation(s)
- Smrithi Sunil
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
| | - Sefik Evren Erdener
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Xiaojun Cheng
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sreekanth Kura
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Jianbo Tang
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - John Jiang
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kavon Karrobi
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kıvılcım Kılıç
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Darren Roblyer
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215, USA
| | - David A Boas
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Department of Electrical and Computer Engineering, Boston University, Boston, MA 02215, USA
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Yao G, Li J, Liu S, Wang J, Cao X, Li X, Cheng L, Chen H, Xu Y. Alterations of Functional Connectivity in Stroke Patients With Basal Ganglia Damage and Cognitive Impairment. Front Neurol 2020; 11:980. [PMID: 33013648 PMCID: PMC7511868 DOI: 10.3389/fneur.2020.00980] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 07/28/2020] [Indexed: 01/01/2023] Open
Abstract
Background: Stroke with basal ganglia damage (SBG) is a neurological disorder characterized by cognitive impairment. The neurobiological mechanism of cognitive impairment in stroke patients with basal ganglia damage (SBG patients) remains unclear. This study aimed to explore the underlying neurobiological mechanism of cognitive impairment in SBG patients using resting-state functional magnetic resonance imaging (rs-fMRI). Methods: The differences in functional connectivity (FC) between 14 SBG patients (average age: 61.00 ± 7.45 years) and 21 healthy controls (HC) (average age: 60.67 ± 6.95 years) were examined using voxel-mirrored homotopic connectivity (VMHC) and degree centrality (DC). Moreover, we compared the cognitive functions of SBG patients with HC using the Chinese Revised Wechsler Adult Intelligence Scale (WAIS-RC) and Wechsler Memory Scale (WMS). Results: Full-scale intelligence quotient (FIQ) (t = 2.810, p < 0.010) and memory quotient (MQ) (t = 2.920, p < 0.010) scores of SBG patients were significantly lower than those of HC. Compared with HC, significantly decreased VMHC values in the bilateral angular gyrus, supramarginal gyrus, inferior frontal gyrus, middle temporal gyrus, hippocampus, precuneus, precentral gyrus, and middle occipital gyrus and decreased DC values in the right supramarginal gyrus, bilateral angular gyrus, and right postcentral gyrus were observed in SBG patients. Moreover, the VMHC values in the angular gyrus, inferior frontal gyrus, supramarginal gyrus, and middle temporal gyrus and the DC values in the right supramarginal gyrus were significantly correlated with cognitive functions in all participants. Conclusion: Our findings may provide a neural basis for cognitive impairments in SBG patients. Furthermore, local abnormalities of functional networks and interhemispheric interaction deficits may provide new ideas and insights for understanding and treating SBG patients' cognitive impairments.
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Affiliation(s)
- Guanqun Yao
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China
| | - Jing Li
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China.,Shanxi Key Laboratory of Artificial Intelligence Assisted Diagnosis and Treatment for Mental Disorder, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Sha Liu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China.,Shanxi Key Laboratory of Artificial Intelligence Assisted Diagnosis and Treatment for Mental Disorder, First Hospital of Shanxi Medical University, Taiyuan, China
| | - Jiaojian Wang
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China.,Center for Language and Brain, Shenzhen Institute of Neuroscience, Shenzhen, China
| | - Xiaohua Cao
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China
| | - Xinrong Li
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China
| | - Long Cheng
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China
| | - Huafu Chen
- The Clinical Hospital of Chengdu Brain Science Institute, MOE Key Lab for Neuroinformation, School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, China
| | - Yong Xu
- Department of Psychiatry, First Hospital/First Clinical Medical College of Shanxi Medical University, Taiyuan, China.,Shanxi Key Laboratory of Artificial Intelligence Assisted Diagnosis and Treatment for Mental Disorder, First Hospital of Shanxi Medical University, Taiyuan, China.,MDT Center for Cognitive Impairment and Sleep Disorders, First Hospital of Shanxi Medical University, Taiyuan, China
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Schevenels K, Price CJ, Zink I, De Smedt B, Vandermosten M. A Review on Treatment-Related Brain Changes in Aphasia. NEUROBIOLOGY OF LANGUAGE (CAMBRIDGE, MASS.) 2020; 1:402-433. [PMID: 37215585 PMCID: PMC10158631 DOI: 10.1162/nol_a_00019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Accepted: 06/29/2020] [Indexed: 05/24/2023]
Abstract
Numerous studies have investigated brain changes associated with interventions targeting a range of language problems in patients with aphasia. We strive to integrate the results of these studies to examine (1) whether the focus of the intervention (i.e., phonology, semantics, orthography, syntax, or rhythmic-melodic) determines in which brain regions changes occur; and (2a) whether the most consistent changes occur within the language network or outside, and (2b) whether these are related to individual differences in language outcomes. The results of 32 studies with 204 unique patients were considered. Concerning (1), the location of treatment-related changes does not clearly depend on the type of language processing targeted. However, there is some support that rhythmic-melodic training has more impact on the right hemisphere than linguistic training. Concerning (2), we observed that language recovery is not only associated with changes in traditional language-related structures in the left hemisphere and homolog regions in the right hemisphere, but also with more medial and subcortical changes (e.g., precuneus and basal ganglia). Although it is difficult to draw strong conclusions, because there is a lack of systematic large-scale studies on this topic, this review highlights the need for an integrated approach to investigate how language interventions impact on the brain. Future studies need to focus on larger samples preserving subject-specific information (e.g., lesion effects) to cope with the inherent heterogeneity of stroke-induced aphasia. In addition, recovery-related changes in whole-brain connectivity patterns need more investigation to provide a comprehensive neural account of treatment-related brain plasticity and language recovery.
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Affiliation(s)
- Klara Schevenels
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Cathy J. Price
- Welcome Centre for Human Neuroimaging, Institute of Neurology, University College London, UK
| | - Inge Zink
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Bert De Smedt
- Parenting and Special Education Research Unit, Faculty of Psychology and Educational Sciences, KU Leuven, Leuven, Belgium
| | - Maaike Vandermosten
- Experimental Oto-Rhino-Laryngology, Department of Neurosciences, KU Leuven, Leuven, Belgium
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10
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Imaging Developmental and Interventional Plasticity Following Perinatal Stroke. Can J Neurol Sci 2020; 48:157-171. [DOI: 10.1017/cjn.2020.166] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
ABSTRACT:Perinatal stroke occurs around the time of birth and leads to lifelong neurological disabilities including hemiparetic cerebral palsy. Magnetic resonance imaging (MRI) has revolutionized our understanding of developmental neuroplasticity following early injury, quantifying volumetric, structural, functional, and metabolic compensatory changes after perinatal stroke. Such techniques can also be used to investigate how the brain responds to treatment (interventional neuroplasticity). Here, we review the current state of knowledge of how established and emerging neuroimaging modalities are informing neuroplasticity models in children with perinatal stroke. Specifically, we review structural imaging characterizing lesion characteristics and volumetrics, diffusion tensor imaging investigating white matter tracts and networks, task-based functional MRI for localizing function, resting state functional imaging for characterizing functional connectomes, and spectroscopy examining neurometabolic changes. Key challenges and exciting avenues for future investigations are also considered.
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Al Harrach M, Rousseau F, Groeschel S, Chabrier S, Hertz-Pannier L, Lefevre J, Dinomais M. Is the Blood Oxygenation Level-Dependent fMRI Response to Motor Tasks Altered in Children After Neonatal Stroke? Front Hum Neurosci 2020; 14:154. [PMID: 32410976 PMCID: PMC7202247 DOI: 10.3389/fnhum.2020.00154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 04/07/2020] [Indexed: 12/13/2022] Open
Abstract
Functional MRI is increasingly being used in the assessment of brain activation and connectivity following stroke. Many of these studies rely on the Blood Oxygenation Level Dependent (BOLD) contrast. However, the stability, as well as the accuracy of the BOLD response to motor task in the ipsilesional hemisphere, remains ambiguous. In this work, the BOLD signal acquired from both healthy and affected hemispheres was analyzed in 7-year-old children who sustained a Neonatal Arterial Ischemic Stroke (NAIS). Accordingly, a repetitive motor task of the contralesional and the ipsilesional hands was performed by 33 patients with unilateral lesions. These patients were divided into two groups: those without cerebral palsy (NAIS), and those with cerebral palsy (CP). The BOLD signal time course was obtained from distinctly defined regions of interest (ROIs) extracted from the functional activation maps of 30 healthy controls with similar age and demographic characteristics as the patients. An ROI covering both the primary motor cortex (M1) and the primary somatosensory cortex (S1) was also tested. Compared with controls, NAIS patients without CP had similar BOLD amplitude variation for both the contralesional and the ipsilesional hand movements. However, in the case of NAIS patients with CP, a significant difference in the averaged BOLD amplitude was found between the healthy and affected hemisphere. In both cases, no progressive attenuation of the BOLD signal amplitude was observed throughout the task epochs. Besides, results also showed a correlation between the BOLD signal percentage variation of the lesioned hemisphere and the dexterity level. These findings suggest that for patients who sustained a NAIS with no extensive permanent motor impairment, BOLD signal-based data analysis can be a valuable tool for the evaluation of functional brain networks.
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Affiliation(s)
- Mariam Al Harrach
- Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS) EA7315, Université d'Angers, Polytech Angers, Angers, France
| | | | - Samuel Groeschel
- Department of Child Neurology, Paediatric Neuroimaging, University Hospital, Tübingen, Germany
| | - Stéphane Chabrier
- INSERM UMR1059 Sainbiose, Univ Saint-Étienne, Univ Lyon, Saint-Étienne, France.,INSERM, CIC 1408, CHU Saint-Étienne, French Centre for Paediatric Stroke, Paediatric Physical and Rehabilitation Medicine Department, Saint-Étienne, France
| | - Lucie Hertz-Pannier
- INSERM U114 Neurospin, UNIACT, Institut Joliot, Université de Paris, CEA-Paris Saclay, Gif sur Yvette, France
| | - Julien Lefevre
- UMR CNRS 7289, Aix Marseille Université, Institut de Neurosciences de la Timone, Marseille, France
| | - Mickael Dinomais
- Laboratoire Angevin de Recherche en Ingénierie des Systèmes (LARIS) EA7315, Université d'Angers, Polytech Angers, Angers, France.,CHU Angers, Département de Médecine Physique et de Réadaptions and LUNAM, Angers, France
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12
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How reliable is cerebral blood flow to map changes in neuronal activity? Auton Neurosci 2019; 217:71-79. [PMID: 30744905 DOI: 10.1016/j.autneu.2019.01.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Revised: 12/17/2018] [Accepted: 01/27/2019] [Indexed: 02/06/2023]
Abstract
Neuroimaging techniques, such as functional MRI, map brain activity through hemodynamic-based signals, and are invaluable diagnostic tools in several neurological disorders such as stroke and dementia. Hemodynamic signals are normally precisely related to the underlying neuronal activity through neurovascular coupling mechanisms that ensure the supply of blood, glucose and oxygen to neurons at work. The knowledge of neurovascular coupling has greatly advanced over the last 30 years, it involves multifaceted interactions between excitatory and inhibitory neurons, astrocytes, and the microvessels. While the tight relationship between blood flow and neuronal activity forms a fundamental brain function, whether neurovascular coupling mechanisms are reliable across physiological and pathological conditions has been questioned. In this review, we interrogate the relationship between blood flow and neuronal activity during activation of different brain pathways: a sensory stimulation driven by glutamate, and stimulation of neuromodulatory pathways driven by acetylcholine or noradrenaline, and we compare the underlying neurovascular coupling mechanisms. We further question if neurovascular coupling mechanisms are affected by changing brain states, as seen in behavioral conditions of sleep, wakefulness, attention and in pathological conditions. Finally, we provide a short overview of how alterations of the brain vasculature could compromise the reliability of neurovascular coupling. Overall, while neurovascular coupling requires activation of common signalling pathways, alternate unique cascades exist depending on the activated pathways. Further studies are needed to fully elucidate the alterations in neurovascular coupling across brain states and pathological conditions.
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13
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Bazzigaluppi P, Adams C, Koletar MM, Dorr A, Pikula A, Carlen PL, Stefanovic B. Oophorectomy Reduces Estradiol Levels and Long-Term Spontaneous Neurovascular Recovery in a Female Rat Model of Focal Ischemic Stroke. Front Mol Neurosci 2018; 11:338. [PMID: 30271324 PMCID: PMC6146137 DOI: 10.3389/fnmol.2018.00338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Although epidemiological evidence suggests significant sex and gender-based differences in stroke risk and recovery, females have been widely under-represented in preclinical stroke research. The neurovascular sequelae of brain ischemia in females, in particular, are largely uncertain. We set out to address this gap by a multimodal in vivo study of neurovascular recovery from endothelin-1 model of cortical focal-stroke in sham vs. ovariectomized female rats. Three weeks post ischemic insult, sham operated females recapitulated the phenotype previously reported in male rats in this model, of normalized resting perfusion but sustained peri-lesional cerebrovascular hyperreactivity. In contrast, ovariectomized (Ovx) females showed reduced peri-lesional resting blood flow, and elevated cerebrovascular responsivity to hypercapnia in the peri-lesional and contra-lateral cortices. Electrophysiological recordings showed an attenuation of theta to low-gamma phase-amplitude coupling in the peri-lesional tissue of Ovx animals, despite relative preservation of neuronal power. Further, this chronic stage neuronal network dysfunction was inversely correlated with serum estradiol concentration. Our pioneering data demonstrate dramatic differences in spontaneous recovery in the neurovascular unit between Ovx and Sham females in the chronic stage of stroke, underscoring the importance of considering hormonal-dependent aspects of the ischemic sequelae in the development of novel therapeutic approaches and patient recruitment in clinical trials.
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Affiliation(s)
- Paolo Bazzigaluppi
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Conner Adams
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Margaret M Koletar
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Adrienne Dorr
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Aleksandra Pikula
- Adult Vascular Neurology, Toronto Western Hospital, Toronto, ON, Canada
| | - Peter L Carlen
- Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Bojana Stefanovic
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
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14
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Bazzigaluppi P, Lake EM, Beckett TL, Koletar MM, Weisspapir I, Heinen S, Mester J, Lai A, Janik R, Dorr A, McLaurin J, Stanisz GJ, Carlen PL, Stefanovic B. Imaging the Effects of β-Hydroxybutyrate on Peri-Infarct Neurovascular Function and Metabolism. Stroke 2018; 49:2173-2181. [DOI: 10.1161/strokeaha.118.020586] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Paolo Bazzigaluppi
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | - Evelyn M. Lake
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Tina L. Beckett
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Margaret M. Koletar
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Iliya Weisspapir
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | | | - James Mester
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Biological Sciences (J.M.)
| | - Aaron Lai
- Department of Laboratory Medicine and Pathobiology (A.L., J.M.)
| | - Rafal Janik
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Adrienne Dorr
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - JoAnne McLaurin
- Department of Laboratory Medicine and Pathobiology (A.L., J.M.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Greg J. Stanisz
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Peter L. Carlen
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | - Bojana Stefanovic
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
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15
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Larivière S, Ward NS, Boudrias MH. Disrupted functional network integrity and flexibility after stroke: Relation to motor impairments. NEUROIMAGE-CLINICAL 2018; 19:883-891. [PMID: 29946512 PMCID: PMC6008503 DOI: 10.1016/j.nicl.2018.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/17/2018] [Accepted: 06/07/2018] [Indexed: 12/21/2022]
Abstract
Previous studies investigating brain activation present during upper limb movement after stroke have greatly detailed activity alterations in the ipsi- and contralesional primary motor cortices (M1). Despite considerable interest in M1, investigations into the integration and coordination of large-scale functional networks subserving motor, sensory, and cognitive control after stroke remain scarce. The purpose of this study was to assess non-static functional connectivity within whole-brain networks involved in the production of isometric, visually-paced hand grips. Seventeen stroke patients and 24 healthy controls underwent functional MRI while performing a series of 50 isometric hand grips with their affected hand (stroke patients) or dominant hand (control subjects). We used task-based multivariate functional connectivity to derive spatial and temporal information of whole-brain networks specifically underlying hand movement. This technique has the advantage of extracting within-network commonalities across groups and identifying connectivity differences between these groups. We further used a nonparametric statistical approach to identify group differences in regional activity within these task-specific networks and assess whether such alterations were related to the degree of motor impairment in stroke patients. Our whole-brain multivariate analysis revealed group differences in two networks: (1) a motor network, including pre- and postcentral gyri, dorsal and ventral premotor cortices, as well as supplementary motor area, in which stroke patients showed reduced task-related activation compared to controls, and (2) a default-mode network (DMN), including the posterior cingulate cortex, precuneus, and medial prefrontal cortex, in which patients showed less deactivation than controls. Within-network group differences revealed decreased activity in ipsilesional primary sensorimotor cortex in stroke patients, which also positively correlated with lower levels of motor impairment. Moreover, the temporal information extracted from the functional networks revealed that stroke patients did not show a reciprocal DMN deactivation peak following activation of their motor network. This finding suggests that allocation of functional resources to motor areas during hand movement may impair their ability to efficiently switch from one network to another. Taken together, our study expands our understanding of functional reorganization during motor recovery after a stroke, and suggests that modulation of ipsilesional sensorimotor activity may increase the integrity of a whole-brain motor network, contribute to better motor performance, and optimize network flexibility. We assessed connectivity in task-based brain networks underlying hand movement. We compared network properties between stroke patients and healthy controls. Stroke patients have altered default-mode and motor network connectivity. Patients also showed poorer motor performance and impaired network flexibility.
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Affiliation(s)
- Sara Larivière
- McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montréal, Qc, Canada; Department of Neurology and Neurosurgery, McGill University, Montréal, Qc, Canada
| | - Nick S Ward
- Sobell Department of Motor Neuroscience, Institute of Neurology, University College, London, UK
| | - Marie-Hélène Boudrias
- School of Physical and Occupational Therapy, McGill University, Montréal, Qc, Canada; Center for Interdisciplinary Research in Rehabilitation of Greater Montreal (CRIR), Montréal, Qc, Canada.
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16
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Chen PC, Shoa KH, Jao JC, Hsiao CC. Dynamic magnetic resonance imaging of carbogen challenge on awake rabbit brain at 1.5T. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2018; 26:997-1009. [PMID: 30223421 DOI: 10.3233/xst-180395] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
BACKGROUND Anesthesia may alter the cellular components contributing to the magnetic resonance imaging (MRI) signal intensities. Developing awake animal models to evaluate cerebral function has grown in importance. OBJECTIVE To investigate a noninvasive strategy for dynamic MRI (dMRI) of awake rabbits during carbogen challenge. METHODS A nonmetallic assistive device with a self-adhering wrap secure procedure was developed for the head fixation of awake rabbits. Multi-shot gradient echo echo-planar imaging sequence was applied for the dMRI on a 1.5 T clinical MRI scanner with a quadrature head coil. The carbogen challenge pattern was applied in a sequence of air - carbogen - air - carbogen - air. Twelve scans were performed for each block of carbogen challenge. T2-weighted fast-spin echo and T1-weighted gradient echo sequences were performed before and after dMRI to evaluate the head position shifts. The whole dMRI scan time was about 30 minutes. RESULTS The position shift of 8 rabbits in the x-and y-direction was less than 3%. The average MRI signal intensities (SI) from the 8 rabbits during carbogen challenge was fitted well using exponential growth and decay functions. The average MRI SI increase due to carbogen inhaling was 1.51%. CONCLUSIONS The proposed strategy for head dMRI on an awake rabbit during carbogen challenge is feasible.
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Affiliation(s)
- Po-Chou Chen
- Department of Biomedical Engineering, I-Shou University, Kaohsiung City, Taiwan, ROC
| | - Kuan-Hsiung Shoa
- Department of Radiology, Jhong Jheng Orthopedic Hospital, Kaohsiung City, Taiwan, ROC
| | - Jo-Chi Jao
- Department of Medical Imaging and Radiological Sciences, College of Health Sciences, Kaohsiung Medical University, Kaohsiung City, Taiwan, ROC
| | - Chia-Chi Hsiao
- Department of Radiology, Kaohsiung Veterans General Hospital, Kaohsiung City, Taiwan, ROC
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17
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Hall CN, Howarth C, Kurth-Nelson Z, Mishra A. Interpreting BOLD: towards a dialogue between cognitive and cellular neuroscience. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0348. [PMID: 27574302 DOI: 10.1098/rstb.2015.0348] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/11/2016] [Indexed: 12/11/2022] Open
Abstract
Cognitive neuroscience depends on the use of blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) to probe brain function. Although commonly used as a surrogate measure of neuronal activity, BOLD signals actually reflect changes in brain blood oxygenation. Understanding the mechanisms linking neuronal activity to vascular perfusion is, therefore, critical in interpreting BOLD. Advances in cellular neuroscience demonstrating differences in this neurovascular relationship in different brain regions, conditions or pathologies are often not accounted for when interpreting BOLD. Meanwhile, within cognitive neuroscience, the increasing use of high magnetic field strengths and the development of model-based tasks and analyses have broadened the capability of BOLD signals to inform us about the underlying neuronal activity, but these methods are less well understood by cellular neuroscientists. In 2016, a Royal Society Theo Murphy Meeting brought scientists from the two communities together to discuss these issues. Here, we consolidate the main conclusions arising from that meeting. We discuss areas of consensus about what BOLD fMRI can tell us about underlying neuronal activity, and how advanced modelling techniques have improved our ability to use and interpret BOLD. We also highlight areas of controversy in understanding BOLD and suggest research directions required to resolve these issues.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
| | - Clare Howarth
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Zebulun Kurth-Nelson
- Max Planck UCL Centre for Computational Psychiatry and Ageing Research, University College London, London, UK
| | - Anusha Mishra
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
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18
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Bazzigaluppi P, Ebrahim Amini A, Weisspapir I, Stefanovic B, Carlen PL. Hungry Neurons: Metabolic Insights on Seizure Dynamics. Int J Mol Sci 2017; 18:ijms18112269. [PMID: 29143800 PMCID: PMC5713239 DOI: 10.3390/ijms18112269] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 10/24/2017] [Accepted: 10/26/2017] [Indexed: 12/18/2022] Open
Abstract
Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dys)function and extracellular ionic species (dys)regulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilization) of seizures pathophysiology revealing (in most cases) reduced metabolism in the inter-ictal period and increased metabolism in the seconds preceding and during the appearance of seizures. In the present review, we summarize the clinical and preclinical observations showing metabolic dysregulation during epileptogenesis, seizure initiation, and termination, and in the inter-ictal period. Recent preclinical studies have shown that 2-Deoxyglucose (2-DG, a glycolysis blocker) is a novel therapeutic approach to reduce seizures. Furthermore, we present initial evidence for the effectiveness of 2-DG in arresting 4-Aminopyridine induced neocortical seizures in vivo in the mouse.
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Affiliation(s)
- Paolo Bazzigaluppi
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Sunnybrook Research Institute, Medical Biophysics, Toronto, ON M4N 3M5, Canada.
| | - Azin Ebrahim Amini
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto, Toronto, ON M5S 3G9, Canada.
| | - Iliya Weisspapir
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
| | - Bojana Stefanovic
- Sunnybrook Research Institute, Medical Biophysics, Toronto, ON M4N 3M5, Canada.
| | - Peter L Carlen
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Department of Medicine & Physiology, and Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto, Toronto, ON M5S 1A8, Canada.
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19
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Siegel JS, Shulman GL, Corbetta M. Measuring functional connectivity in stroke: Approaches and considerations. J Cereb Blood Flow Metab 2017; 37:2665-2678. [PMID: 28541130 PMCID: PMC5536814 DOI: 10.1177/0271678x17709198] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Recent research has demonstrated the importance of global changes to the functional organization of brain network following stroke. Resting functional magnetic resonance imaging (R-fMRI) is a non-invasive tool that enables the measurement of functional connectivity (FC) across the entire brain while placing minimal demands on the subject. For these reasons, it is a uniquely appealing tool for studying the distant effects of stroke. However, R-fMRI studies rely on a number of premises that cannot be assumed without careful validation in the context of stroke. Here, we describe strategies to identify and mitigate confounds specific to R-fMRI research in cerebrovascular disease. Five main topics are discussed: (a) achieving adequate co-registration of lesioned brains, (b) identifying and removing hemodynamic lags in resting BOLD, (c) identifying other vascular disruptions that affect the resting BOLD signal, (d) selecting an appropriate control cohort, and (e) acquiring sufficient fMRI data to reliably identify FC changes. For each topic, we provide guidelines for steps to improve the interpretability and reproducibility of FC-stroke research. We include a table of confounds and approaches to identify and mitigate each. Our recommendations extend to any research using R-fMRI to study diseases that might alter cerebrovascular flow and dynamics or brain anatomy.
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Affiliation(s)
- Joshua S Siegel
- 1 Department of Neurology, Washington University School of Medicine, St. Louis, USA
| | - Gordon L Shulman
- 1 Department of Neurology, Washington University School of Medicine, St. Louis, USA
| | - Maurizio Corbetta
- 1 Department of Neurology, Washington University School of Medicine, St. Louis, USA.,2 Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, USA.,3 Department of Psychology, Washington University School of Medicine, St. Louis, USA.,4 Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, USA.,5 Department of Neuroscience, University of Padua, Padua, Italy
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20
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Silva AC. Anatomical and functional neuroimaging in awake, behaving marmosets. Dev Neurobiol 2016; 77:373-389. [PMID: 27706916 DOI: 10.1002/dneu.22456] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/28/2016] [Accepted: 09/28/2016] [Indexed: 12/12/2022]
Abstract
The common marmoset (Callithrix jacchus) is a small New World monkey that has gained significant recent interest in neuroscience research, not only because of its compatibility with gene editing techniques, but also due to its tremendous versatility as an experimental animal model. Neuroimaging modalities, including anatomical (MRI) and functional magnetic resonance imaging (fMRI), complemented by two-photon laser scanning microscopy and electrophysiology, have been at the forefront of unraveling the anatomical and functional organization of the marmoset brain. High-resolution anatomical MRI of the marmoset brain can be obtained with remarkable cytoarchitectonic detail. Functional MRI of the marmoset brain has been used to study various sensory systems, including somatosensory, auditory, and visual pathways, while resting-state fMRI studies have unraveled functional brain networks that bear great correspondence to those previously described in humans. Two-photon laser scanning microscopy of the marmoset brain has enabled the simultaneous recording of neuronal activity from thousands of neurons with single cell spatial resolution. In this article, we aim to review the main results obtained by our group and by our colleagues in applying neuroimaging techniques to study the marmoset brain. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 77: 373-389, 2017.
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Affiliation(s)
- Afonso C Silva
- Cerebral Microcirculation Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892
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