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Qi Y, Xu Y, Wang H, Wang Q, Li M, Han B, Liu H. Network Reorganization for Neurophysiological and Behavioral Recovery Following Stroke. Cent Nerv Syst Agents Med Chem 2024; 24:117-128. [PMID: 38299298 DOI: 10.2174/0118715249277597231226064144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/15/2023] [Accepted: 12/06/2023] [Indexed: 02/02/2024]
Abstract
Stroke continues to be the main cause of motor disability worldwide. While rehabilitation has been promised to improve recovery after stroke, efficacy in clinical trials has been mixed. We need to understand the cortical recombination framework to understand how biomarkers for neurophysiological reorganized neurotechnologies alter network activity. Here, we summarize the principles of the movement network, including the current evidence of changes in the connections and function of encephalic regions, recovery from stroke and the therapeutic effects of rehabilitation. Overall, improvements or therapeutic effects in limb motor control following stroke are correlated with the effects of interhemispheric competition or compensatory models of the motor supplementary cortex. This review suggests that future research should focus on cross-regional communication and provide fundamental insights into further treatment and rehabilitation for post-stroke patients.
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Affiliation(s)
- Yuan Qi
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
| | - Yujie Xu
- Chengde Medical College Affiliated Hospital, Chengde, Hebei, CN, China
| | - Huailu Wang
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
| | - Qiujia Wang
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
| | - Meijie Li
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
| | - Bo Han
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
| | - Haijie Liu
- Department of Neurology, Xuanwu Hospital Capital Medical University, Beijing CN, China
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Brunner C, Denis NL, Gertz K, Grillet M, Montaldo G, Endres M, Urban A. Brain-wide continuous functional ultrasound imaging for real-time monitoring of hemodynamics during ischemic stroke. J Cereb Blood Flow Metab 2024; 44:6-18. [PMID: 37503862 PMCID: PMC10905631 DOI: 10.1177/0271678x231191600] [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: 06/07/2023] [Revised: 07/13/2023] [Accepted: 07/14/2023] [Indexed: 07/29/2023]
Abstract
Ischemic stroke occurs abruptly causing sudden neurologic deficits, and therefore, very little is known about hemodynamic perturbations in the brain immediately after stroke onset. Here, functional ultrasound imaging was used to monitor variations in relative cerebral blood volume (rCBV) compared to baseline. rCBV levels were analyzed brain-wide and continuously at high spatiotemporal resolution (100 μm, 2 Hz) until 70mins after stroke onset in rats. We compared two stroke models, with either a permanent occlusion of the middle cerebral artery (MCAo) or a tandem occlusion of both the common carotid and middle cerebral arteries (CCAo + MCAo). We observed a typical hemodynamic pattern, including a quick drop of the rCBV after MCAo, followed by spontaneous reperfusion of several brain regions located in the vicinity of the ischemic core. The severity and location of the ischemia were variable within groups. On average, the severity of the ischemia was in good agreement with the lesion volume (24 hrs after stroke) for MCAo group, while larger for the CCAo + MCAo model. For both groups, we observed that infarcts extended to initially non-ischemic regions located rostrally to the ischemic core. These regions strongly colocalize with the origin of transient hemodynamic events associated with spreading depolarizations.
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Affiliation(s)
- Clément Brunner
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Interuniversity Microelectronics Centre, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Nielsen Lagumersindez Denis
- Department of Neurology and Center for Stroke Research Berlin, Charité-Universitätsmedizin, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Karen Gertz
- Department of Neurology and Center for Stroke Research Berlin, Charité-Universitätsmedizin, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Micheline Grillet
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Interuniversity Microelectronics Centre, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Gabriel Montaldo
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Interuniversity Microelectronics Centre, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
| | - Matthias Endres
- Department of Neurology and Center for Stroke Research Berlin, Charité-Universitätsmedizin, Berlin, Germany
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
- German Centre for Cardiovascular Research (DZHK), Berlin, Germany
| | - Alan Urban
- Neuro-Electronics Research Flanders, Leuven, Belgium
- Vlaams Instituut voor Biotechnologie, Leuven, Belgium
- Interuniversity Microelectronics Centre, Leuven, Belgium
- Department of Neurosciences, KU Leuven, Leuven, Belgium
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3
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Brunner C, Montaldo G, Urban A. Functional ultrasound imaging of stroke in awake rats. eLife 2023; 12:RP88919. [PMID: 37988288 PMCID: PMC10662948 DOI: 10.7554/elife.88919] [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] [Indexed: 11/23/2023] Open
Abstract
Anesthesia is a major confounding factor in preclinical stroke research as stroke rarely occurs in sedated patients. Moreover, anesthesia affects both brain functions and the stroke outcome acting as neurotoxic or protective agents. So far, no approaches were well suited to induce stroke while imaging hemodynamics along with simultaneous large-scale recording of brain functions in awake animals. For this reason, the first critical hours following the stroke insult and associated functional alteration remain poorly understood. Here, we present a strategy to investigate both stroke hemodynamics and stroke-induced functional alterations without the confounding effect of anesthesia, i.e., under awake condition. Functional ultrasound (fUS) imaging was used to continuously monitor variations in cerebral blood volume (CBV) in +65 brain regions/hemispheres for up to 3 hr after stroke onset. The focal cortical ischemia was induced using a chemo-thrombotic agent suited for permanent middle cerebral artery occlusion in awake rats and followed by ipsi- and contralesional whiskers stimulation to investigate on the dynamic of the thalamocortical functions. Early (0-3 hr) and delayed (day 5) fUS recording enabled to characterize the features of the ischemia (location, CBV loss), spreading depolarizations (occurrence, amplitude) and functional alteration of the somatosensory thalamocortical circuits. Post-stroke thalamocortical functions were affected at both early and later time points (0-3 hr and 5 days) after stroke. Overall, our procedure facilitates early, continuous, and chronic assessments of hemodynamics and cerebral functions. When integrated with stroke studies or other pathological analyses, this approach seeks to enhance our comprehension of physiopathologies towards the development of pertinent therapeutic interventions.
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Affiliation(s)
- Clément Brunner
- Neuro-Electronics Research FlandersLeuvenBelgium
- Vlaams Instituut voor BiotechnologieLeuvenBelgium
- Interuniversity Microelectronics CentreLeuvenBelgium
- Department of Neurosciences, KU LeuvenLeuvenBelgium
| | - Gabriel Montaldo
- Neuro-Electronics Research FlandersLeuvenBelgium
- Vlaams Instituut voor BiotechnologieLeuvenBelgium
- Interuniversity Microelectronics CentreLeuvenBelgium
- Department of Neurosciences, KU LeuvenLeuvenBelgium
| | - Alan Urban
- Neuro-Electronics Research FlandersLeuvenBelgium
- Vlaams Instituut voor BiotechnologieLeuvenBelgium
- Interuniversity Microelectronics CentreLeuvenBelgium
- Department of Neurosciences, KU LeuvenLeuvenBelgium
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4
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Cheng S, Xin R, Zhao Y, Wang P, Feng W, Liu P. Evaluation of fMRI activation in post-stroke patients with movement disorders after repetitive transcranial magnetic stimulation: a scoping review. Front Neurol 2023; 14:1192545. [PMID: 37404941 PMCID: PMC10315664 DOI: 10.3389/fneur.2023.1192545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/25/2023] [Indexed: 07/06/2023] Open
Abstract
Background Movement disorders are one of the most common stroke residual effects, which cause a major stress on their families and society. Repetitive transcranial magnetic stimulation (rTMS) could change neuroplasticity, which has been suggested as an alternative rehabilitative treatment for enhancing stroke recovery. Functional magnetic resonance imaging (fMRI) is a promising tool to explore neural mechanisms underlying rTMS intervention. Object Our primary goal is to better understand the neuroplastic mechanisms of rTMS in stroke rehabilitation, this paper provides a scoping review of recent studies, which investigate the alteration of brain activity using fMRI after the application of rTMS over the primary motor area (M1) in movement disorders patients after stroke. Method The database PubMed, Embase, Web of Science, WanFang Chinese database, ZhiWang Chinese database from establishment of each database until December 2022 were included. Two researchers reviewed the study, collected the information and the relevant characteristic extracted to a summary table. Two researchers also assessed the quality of literature with the Downs and Black criteria. When the two researchers unable to reach an agreement, a third researcher would have been consulted. Results Seven hundred and eleven studies in all were discovered in the databases, and nine were finally enrolled. They were of good quality or fair quality. The literature mainly involved the therapeutic effect and imaging mechanisms of rTMS on improving movement disorders after stroke. In all of them, there was improvement of the motor function post-rTMS treatment. Both high-frequency rTMS (HF-rTMS) and low-frequency rTMS (LF-rTMS) can induce increased functional connectivity, which may not directly correspond to the impact of rTMS on the activation of the stimulated brain areas. Comparing real rTMS with sham group, the neuroplastic effect of real rTMS can lead to better functional connectivity in the brain network in assisting stroke recovery. Conclusion rTMS allows the excitation and synchronization of neural activity, promotes the reorganization of brain function, and achieves the motor function recovery. fMRI can observe the influence of rTMS on brain networks and reveal the neuroplasticity mechanism of post-stroke rehabilitation. The scoping review helps us to put forward a series of recommendations that might guide future researchers exploring the effect of motor stroke treatments on brain connectivity.
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Affiliation(s)
- Siman Cheng
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Rong Xin
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Yan Zhao
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Pu Wang
- Department of Rehabilitation Medicine, The Seventh Affiliated Hospital, Sun Yat-sen University, Shenzhen, Guangdong, China
| | - Wuwei Feng
- Department of Neurology, Medical University of South Carolina, Charleston, SC, United States
| | - Peng Liu
- Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
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5
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Patzwaldt K, Berezhnoy G, Ionescu T, Schramm L, Wang Y, Owczorz M, Calderón E, Poli S, Serna Higuita LM, Gonzalez-Menendez I, Quintanilla-Martinez L, Herfert K, Pichler B, Trautwein C, Castaneda-Vega S. Repurposing the mucolytic agent ambroxol for treatment of sub-acute and chronic ischaemic stroke. Brain Commun 2023; 5:fcad099. [PMID: 37065090 PMCID: PMC10090797 DOI: 10.1093/braincomms/fcad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 01/31/2023] [Accepted: 03/27/2023] [Indexed: 03/31/2023] Open
Abstract
Ambroxol is a well-known mucolytic expectorant, which has gained much attention in amyotrophic lateral sclerosis, Parkinson's and Gaucher's disease. A specific focus has been placed on ambroxol's glucocerebrosidase-stimulating activity, on grounds that the point mutation of the gba1 gene, which codes for this enzyme, is a risk factor for developing Parkinson's disease. However, ambroxol has been attributed other characteristics, such as the potent inhibition of sodium channels, modification of calcium homeostasis, anti-inflammatory effects and modifications of oxygen radical scavengers. We hypothesized that ambroxol could have a direct impact on neuronal rescue if administered directly after ischaemic stroke induction. We longitudinally evaluated 53 rats using magnetic resonance imaging to examine stroke volume, oedema, white matter integrity, resting state functional MRI and behaviour for 1 month after ischemic stroke onset. For closer mechanistic insights, we evaluated tissue metabolomics of different brain regions in a subgroup of animals using ex vivo nuclear magnetic resonance spectroscopy. Ambroxol-treated animals presented reduced stroke volumes, reduced cytotoxic oedema, reduced white matter degeneration, reduced necrosis, improved behavioural outcomes and complex changes in functional brain connectivity. Nuclear magnetic resonance spectroscopy tissue metabolomic data at 24 h post-stroke proposes several metabolites that are capable of minimizing post-ischaemic damage and that presented prominent shifts during ambroxol treatment in comparison to controls. Taking everything together, we propose that ambroxol catalyzes recovery in energy metabolism, cellular homeostasis, membrane repair mechanisms and redox balance. One week of ambroxol administration following stroke onset reduced ischaemic stroke severity and improved functional outcome in the subacute phase followed by reduced necrosis in the chronic stroke phase.
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Affiliation(s)
- Kristin Patzwaldt
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Georgy Berezhnoy
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Tudor Ionescu
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Linda Schramm
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Yi Wang
- Hertie Institute for Clinical Brain Research, Department for Neurology, University Hospital Tuebingen, Tuebingen 72076, Germany
| | - Miriam Owczorz
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Eduardo Calderón
- Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen 72076, Germany
| | - Sven Poli
- Hertie Institute for Clinical Brain Research, Department for Neurology, University Hospital Tuebingen, Tuebingen 72076, Germany
| | - Lina M Serna Higuita
- Institute for Clinical Epidemiology and Applied Biostatistics, University Hospital Tuebingen, Tuebingen 72076, Germany
| | - Irene Gonzalez-Menendez
- Institute of Pathology and Neuropathology, Comprehensive Cancer Center, Eberhard Karls University, Tuebingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) ‘Image-Guided and Functionally Instructed Tumor Therapies’, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Leticia Quintanilla-Martinez
- Institute of Pathology and Neuropathology, Comprehensive Cancer Center, Eberhard Karls University, Tuebingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) ‘Image-Guided and Functionally Instructed Tumor Therapies’, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Kristina Herfert
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Bernd Pichler
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
- Cluster of Excellence iFIT (EXC 2180) ‘Image-Guided and Functionally Instructed Tumor Therapies’, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Christoph Trautwein
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
| | - Salvador Castaneda-Vega
- Werner Siemens Imaging Center, Department of Preclinical Imaging and Radiopharmacy, Eberhard Karls University Tuebingen, Tuebingen 72076, Germany
- Department of Nuclear Medicine and Clinical Molecular Imaging, University Hospital Tuebingen, Tuebingen 72076, Germany
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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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Kuwahara W, Miyawaki Y, Kaneko F. Impact of the Upper Limb Physiotherapy on Behavioral and Brain Adaptations in Post-Stroke Patients. JOURNAL OF ROBOTICS AND MECHATRONICS 2022. [DOI: 10.20965/jrm.2022.p0718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Many stroke patients suffer from motor impairments due to paralysis, and consequently, motor paralysis of upper limbs seems to be particularly prone to residual impairment compared to that of lower limbs. Although ‘learned non-use’ that by managing reasonably well using only the unaffected upper limb in their actions, the patients can achieve their desired behavior, and these success experiences strengthen this pattern of behavior can be interpreted as a post-stroke adaptation, physiotherapy may lead to poor recovery of motor impairment. This review article discusses the impact of upper limb physiotherapy after stroke on behavioral/brain adaptations. Our previous studies demonstrated that patients with severe post-stroke sensorimotor impairments in a chronic phase might have abnormal functional connectivity. To prevent such adaptation after stroke, upper limb physiotherapy is important. In rehabilitation practices, hyper-adaptation has been often observed in not only behavioral but also brain changes. Although several studies are reporting clinical efficacy in patients with moderate to mild paralysis, there might be no effective treatment for patients with severe motor paralysis. To overcome these serious problems, we have developed a novel approach, kinesthetic illusion induced by visual stimulation (KINVIS) therapy. We showed that the effects of KINVIS therapy with therapeutic exercise on upper limb motor functions were mediated by spasticity, and functional connectivity in the brain was also changed with the improvement of motor function after KINVIS therapy. Brain changes underlying behavioral changes need to be more examined, and the adaptation of stroke patients needs to be clarified in detail.
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8
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Chunyong L, Yingkai L, Fuda L, Jiang C, Liu Y. Longitudinal changes of motor cortex function during motor recovery after stroke. Top Stroke Rehabil 2022; 30:342-354. [PMID: 35306960 DOI: 10.1080/10749357.2022.2051829] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND PURPOSE Functional magnetic resonance imaging (fMRI) combined with behavioral assessments was used in our study to investigate the dynamic process of motor cortical functional reorganization after infarction. Therefore, we could provide a theoretical basis and build a useful evaluation system for rehabilitation after stroke and various other cerebral injuries. METHODS Acute stroke patients with a single lesion in the middle cerebral artery supply area and age- and sex-matched healthy volunteers were recruited. A longitudinal observational study involving 20 patients with stroke was conducted using repeated fMRI. Task-based fMRI data were acquired 3 times over a period of 3 months. The behavioral assessment included dynamometer and finger-tapping tests to evaluate the strength and dexterity of each upper arm. RESULTS Behavioral results: The behavioral assessments demonstrated large improvements in session 2 and session 3. fMRI results: The healthy group showed activation in the contralateral primary sensory-motor cortex (S1M1) when executing tasks with either the left or right hand. Compared with the healthy subjects, the patients demonstrated greater activation in the ipsilateral frontal and parietal cortices and supplementary motor areas (SMAs). Across all sessions, more motor activation was observed in the left infarction group. CONCLUSIONS Our results show that motor cortical activation induced by moving the paretic hand changes over time. There were differences in motor functional recovery and motor cortex compensation between the dominant hemisphere and nondominant hemisphere after stroke.
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Affiliation(s)
- Li Chunyong
- Department Encephalopathy, Guangzhou Conghua District Hospital of Traditional Chinese Medicine, Guangzhou, Guangdong, China
| | - Li Yingkai
- Department. Neurology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Liu Fuda
- Area 2, Department of Neurology, Jiangmen Central Hospital, Beijie, Jiangmen City, Guangdong, China
| | - Che Jiang
- Department of neurosurgery, General Hospital of Southern Theatre Command, PLA, Guangzhou, Yuexiu District, China
| | - Yan Liu
- Department Neurology, Foresea Life Insurance Guangzhou General Hospital, Guangzhou, Guangdong, China
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9
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Astrocyte-secreted chordin-like 1 regulates spine density after ischemic injury. Sci Rep 2022; 12:4176. [PMID: 35264691 PMCID: PMC8907233 DOI: 10.1038/s41598-022-08031-4] [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: 10/07/2021] [Accepted: 03/01/2022] [Indexed: 11/09/2022] Open
Abstract
Ischemic injury occurs when the brain is deprived of blood flow, preventing cells from receiving essential nutrients. The injury core is the brain region directly deprived and is surrounded by the peri-infarct area, the region with recovery potential. In the peri-infarct area neurons undergo acute loss of dendritic spines, which modifies synaptic plasticity and determines neuronal survival. Astrocytes can be protective or detrimental to the ischemic injury response depending on the specific stage, yet we lack clear understanding of the underlying mechanisms. Chordin-like 1 (Chrdl1) is an astrocyte-secreted protein that promotes synaptic maturation and limits experience-dependent plasticity in the mouse visual cortex. Given this plasticity-limiting function we asked if Chrdl1 regulates the response to ischemic injury, modelled using photothrombosis (PT). We find that Chrdl1 mRNA is upregulated in astrocytes in the peri-infarct area in both acute and sub-acute phases post-PT. To determine the impact of increased Chrdl1 on the response to PT we analyzed Chrdl1 knock-out mice. We find that absence of Chrdl1 prevents ischemia-induced spine loss in the peri-infarct area and reduces cell death in the core, without impacting gliosis. These findings highlight the important role of astrocyte-secreted proteins in regulating structural plasticity in response to brain ischemic injuries.
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10
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Rapid and Bihemispheric Reorganization of Neuronal Activity in Premotor Cortex after Brain Injury. J Neurosci 2021; 41:9112-9128. [PMID: 34556488 PMCID: PMC8570830 DOI: 10.1523/jneurosci.0196-21.2021] [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: 01/26/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 12/21/2022] Open
Abstract
Brain injuries cause hemodynamic changes in several distant, spared areas from the lesion. Our objective was to better understand the neuronal correlates of this reorganization in awake, behaving female monkeys. We used reversible inactivation techniques to “injure” the primary motor cortex, while continuously recording neuronal activity of the ventral premotor cortex in the two hemispheres, before and after the onset of behavioral impairments. Inactivation rapidly induced profound alterations of neuronal discharges that were heterogeneous within each and across the two hemispheres, occurred during movements of either the affected or nonaffected arm, and varied during different phases of grasping. Our results support that extensive, and much more complex than expected, neuronal reorganization takes place in spared areas of the bihemispheric cortical network involved in the control of hand movements. This broad pattern of reorganization offers potential targets that should be considered for the development of neuromodulation protocols applied early after brain injury. SIGNIFICANCE STATEMENT It is well known that brain injuries cause changes in several distant, spared areas of the network, often in the premotor cortex. This reorganization is greater early after the injury and the magnitude of early changes correlates with impairments. However, studies to date have used noninvasive brain imaging approaches or have been conducted in sedated animals. Therefore, we do not know how brain injuries specifically affect the activity of neurons during the generation of movements. Our study clearly shows how a lesion rapidly impacts neurons in the premotor cortex of both hemispheres. A better understanding of these complex changes can help formulate hypotheses for the development of new treatments that specifically target neuronal reorganization induced by lesions in the brain.
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11
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Blaschke SJ, Hensel L, Minassian A, Vlachakis S, Tscherpel C, Vay SU, Rabenstein M, Schroeter M, Fink GR, Hoehn M, Grefkes C, Rueger MA. Translating Functional Connectivity After Stroke: Functional Magnetic Resonance Imaging Detects Comparable Network Changes in Mice and Humans. Stroke 2021; 52:2948-2960. [PMID: 34281374 DOI: 10.1161/strokeaha.120.032511] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Stefan J Blaschke
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Lukas Hensel
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Anuka Minassian
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
| | - Susan Vlachakis
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
| | - Caroline Tscherpel
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Sabine U Vay
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
| | - Monika Rabenstein
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
| | - Michael Schroeter
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Gereon R Fink
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Mathias Hoehn
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Christian Grefkes
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
| | - Maria A Rueger
- Faculty of Medicine and University Hospital, Department of Neurology, University of Cologne, Germany (S.J.B., L.H., S.V., C.T., S.U.V., M.R., M.S., G.R.F., C.G., M.A.R.)
- In-Vivo NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany (S.J.B., A.M., S.V., M.R., M.S., M.H., C.G., M.A.R.)
- Cognitive Neuroscience Section, Institute of Neuroscience and Medicine (INM-3), Research Centre Juelich, Germany (S.J.B., L.H., C.T., M.S., G.R.F., M.H., C.G., M.A.R.)
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12
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Gil R, Fernandes FF, Shemesh N. Neuroplasticity-driven timing modulations revealed by ultrafast functional magnetic resonance imaging. Neuroimage 2020; 225:117446. [PMID: 33069861 DOI: 10.1016/j.neuroimage.2020.117446] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 09/14/2020] [Accepted: 10/07/2020] [Indexed: 12/13/2022] Open
Abstract
Detecting neuroplasticity in global brain circuits in vivo is key for understanding myriad processes such as memory, learning, and recovery from injury. Functional Magnetic Resonance Imaging (fMRI) is instrumental for such in vivo mappings, yet it typically relies on mapping changes in spatial extent of activation or via signal amplitude modulations, whose interpretation can be highly ambiguous. Importantly, a central aspect of neuroplasticity involves modulation of neural activity timing properties. We thus hypothesized that this temporal dimension could serve as a new marker for neuroplasticity. To detect fMRI signals more associated with the underlying neural dynamics, we developed an ultrafast fMRI (ufMRI) approach facilitating high spatiotemporal sensitivity and resolution in distributed neural pathways. When neuroplasticity was induced in the mouse visual pathway via dark rearing, ufMRI indeed mapped temporal modulations in the entire visual pathway. Our findings therefore suggest a new dimension for exploring neuroplasticity in vivo.
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Affiliation(s)
- Rita Gil
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | | | - Noam Shemesh
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal.
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13
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Lu YC, Wu JJ, Ma H, Hua XY, Xu JG. Functional Organization of Brain Network in Peripheral Neural Anastomosis Rats after Electroacupuncture: An ICA and Connectome Analysis. Neuroscience 2020; 442:216-227. [PMID: 32629154 DOI: 10.1016/j.neuroscience.2020.06.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 11/19/2022]
Abstract
Acupuncture is a mild therapy in rehabilitation practice of peripheral nerve injury. Previous studies confirmed the deep participation of brain plasticity in the process of functional restoration. The therapeutic effect of acupuncture is also believed to be closely associated with brain plasticity, especially in the hypothalamus and limbic system. But the fuzzy neural mechanism somehow limits the application or improvement of this therapy. There is little information about the effect of acupuncture on topological properties of brain networks. Instead of functional segregation approach, we utilized graph theory method to analyze the large-scale and distributed properties of information processing. We first established rat model of sciatic nerve injury and performed rehabilitation therapy of electroacupuncture for 120 days. Meanwhile, we used independent component analysis to extract seven sub-networks from the whole brain. Then measurements of graph theory were calculated in each sub-network as well as the whole brain network. We found no significant difference of any measurement in whole brain network among intervention group, model group and normal group. But the assortativity, hierarchy, small-world properties of sub-network displayed significant differences among three groups. It induces changes of neural plasticity in several sub-networks instead of whole brain network. We attributed the changes to the enhancement of the short-term compensatory adaptation and the reduction of the long-term overacting regional information transmission. The present study may shed light on the vague distinction of large-scale property of brain networks after electroacupuncture, which leads to a better understanding of this ancient traditional Chinese therapy.
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Affiliation(s)
- Ye-Chen Lu
- School of Rehabilitation Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Center of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai China
| | - Jia-Jia Wu
- Center of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai China
| | - Hao Ma
- Department of Trauma and Orthopedics, First People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai China
| | - Xu-Yun Hua
- Department of Trauma and Orthopedics, Yueyang Hospital of Intergrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, China
| | - Jian-Guang Xu
- School of Rehabilitation Sciences, Shanghai University of Traditional Chinese Medicine, Shanghai, China; Center of Rehabilitation Medicine, Yueyang Hospital of Integrated Traditional Chinese and Western Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai China.
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14
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Minassian A, Green C, Diedenhofen M, Vogel S, Hess S, Stoeber M, Radmilovic MD, Wiedermann D, Kloppenburg P, Hoehn M. Human Neural Stem Cell Induced Functional Network Stabilization After Cortical Stroke: A Longitudinal Resting-State fMRI Study in Mice. Front Cell Neurosci 2020; 14:86. [PMID: 32317940 PMCID: PMC7155295 DOI: 10.3389/fncel.2020.00086] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/20/2020] [Indexed: 12/12/2022] Open
Abstract
Most stroke studies dealing with functional deficits and assessing stem cell therapy produce extensive hemispheric damage and can be seen as a model for severe clinical strokes. However, mild strokes have a better prospect for functional recovery. Recently, anatomic and behavioral changes have been reported for distal occlusion of the middle cerebral artery (MCA), generating a well-circumscribed and small cortical lesion, which can thus be proposed as mild to moderate cortical stroke. Using this cortical stroke model of moderate severity in the nude mouse, we have studied the functional networks with resting-state functional magnetic resonance imaging (fMRI) for 12 weeks following stroke induction. Further, human neural stem cells (hNSCs) were implanted adjacent to the ischemic lesion, and the stable graft vitality was monitored with bioluminescence imaging (BLI). Differentiation of the grafted neural stem cells was analyzed by immunohistochemistry and by patch-clamp electrophysiology. Following stroke induction, we found a pronounced and continuously rising hypersynchronicity of the sensorimotor networks including both hemispheres, in contrast to the severe stroke filament model where profound reduction of the functional connectivity had been reported by us earlier. The vitality of grafted neural stem cells remained stable throughout the whole 12 weeks observation period. In the stem cell treated animals, functional connectivity did not show hypersynchronicity but was globally slightly reduced below baseline at 2 weeks post-stroke, normalizing thereafter completely. Our resting-state fMRI (rsfMRI) studies on cortical stroke reveal for the first time a hypersynchronicity of the functional brain networks. This hypersynchronicity appears as a hallmark of mild cortical strokes, in contrast to severe strokes with striatal involvement where exclusively hyposynchronicity has been reported. The effect of the stem cell graft was an early and persistent normalization of the functional sensorimotor networks across the whole brain. These novel functional results may help interpret future outcome investigations after stroke and demonstrate the highly promising potential of stem cell treatment for functional outcome improvement after stroke.
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Affiliation(s)
- Anuka Minassian
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Claudia Green
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Michael Diedenhofen
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Stefanie Vogel
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Simon Hess
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Maren Stoeber
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Marina Dobrivojevic Radmilovic
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany.,Department of Histology and Embryology, School of Medicine, University of Zagreb, Zagreb, Croatia
| | - Dirk Wiedermann
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany
| | - Peter Kloppenburg
- Biocenter, Institute for Zoology, University of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Mathias Hoehn
- In-Vivo-NMR Laboratory, Max Planck Institute for Metabolism Research, Cologne, Germany.,Department of Radiology, Leiden University Medical Center, Leiden University, Leiden, Netherlands
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15
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Choi US, Sung YW, Ogawa S. Measurement of ultra-fast signal progression related to face processing by 7T fMRI. Hum Brain Mapp 2020; 41:1754-1764. [PMID: 31925902 PMCID: PMC7268038 DOI: 10.1002/hbm.24907] [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: 09/02/2019] [Revised: 12/10/2019] [Accepted: 12/15/2019] [Indexed: 12/01/2022] Open
Abstract
Given that the brain is a dynamic system, the temporal characteristics of brain function are important. Previous functional magnetic resonance imaging (fMRI) studies have attempted to overcome the limitations of temporal resolution to investigate dynamic states of brain activity. However, finding an fMRI method with sufficient temporal resolution to keep up with the progress of neuronal signals in the brain is challenging. This study aimed to detect between‐hemisphere signal progression, occurring on a timescale of tens of milliseconds, in the ventral brain regions involved in face processing. To this end, we devised an inter‐stimulus interval (ISI) stimulation scheme and used a 7T MRI system to obtain fMRI signals with a high signal‐to‐noise ratio. We conducted two experiments: one to measure signal suppression depending on the ISI and another to measure the relationship between the amount of suppression and the ISI. These two experiments enabled us to measure the signal transfer time from a brain region in the ventral visual stream to its counterpart in the opposite hemisphere through the corpus callosum. These findings demonstrate the feasibility of using fMRI to measure ultra‐fast signals (tens of milliseconds) and could facilitate the elucidation of further aspects of dynamic brain function.
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Affiliation(s)
- Uk-Su Choi
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan.,Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
| | - Yul-Wan Sung
- Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai, Japan
| | - Seiji Ogawa
- Kansei Fukushi Research Institute, Tohoku Fukushi University, Sendai, Japan.,Neuroscience Research Institute, Gachon University, Incheon, Korea
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16
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Crofts A, Kelly ME, Gibson CL. Imaging Functional Recovery Following Ischemic Stroke: Clinical and Preclinical fMRI Studies. J Neuroimaging 2019; 30:5-14. [PMID: 31608550 PMCID: PMC7003729 DOI: 10.1111/jon.12668] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Revised: 09/12/2019] [Accepted: 09/25/2019] [Indexed: 12/18/2022] Open
Abstract
Disability and effectiveness of physical therapy are highly variable following ischemic stroke due to different brain regions being affected. Functional magnetic resonance imaging (fMRI) studies of patients in the months and years following stroke have given some insight into how the brain recovers lost functions. Initially, new pathways are recruited to compensate for the lost region, showing as a brighter blood oxygen‐level‐dependent (BOLD) signal over a larger area during a task than in healthy controls. Subsequently, activity is reduced to baseline levels as pathways become more efficient, mimicking the process of learning typically seen during development. Preclinical models of ischemic stroke aim to enhance understanding of the biology underlying recovery following stroke. However, the pattern of recruitment and focusing seen in humans has not been observed in preclinical fMRI studies that are highly variable methodologically. Resting‐state fMRI studies show more consistency; however, there are still confounding factors to address. Anesthesia and method of stroke induction are the two main sources of variability in preclinical studies; improvements here can reduce variability and increase the intensity and reproducibility of the BOLD response detected by fMRI. Differences in task or stimulus and differences in analysis method also present a source of variability. This review compares clinical and preclinical fMRI studies of recovery following stroke and focuses on how refinement of preclinical models and MRI methods may obtain more representative fMRI data in relation to human studies.
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Affiliation(s)
- Andrew Crofts
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Michael E Kelly
- Preclinical Imaging Facility, Core Biotechnology Services, University of Leicester, Leicester, UK
| | - Claire L Gibson
- School of Psychology, University of Nottingham, Nottingham, UK
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17
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Argibay B, Campos F, Perez-Mato M, Vieites-Prado A, Correa-Paz C, López-Arias E, Da Silva-Candal A, Moreno V, Montero C, Sobrino T, Castillo J, Iglesias-Rey R. Light-Emitting Diode Photobiomodulation After Cerebral Ischemia. Front Neurol 2019; 10:911. [PMID: 31507516 PMCID: PMC6713875 DOI: 10.3389/fneur.2019.00911] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/06/2019] [Indexed: 11/14/2022] Open
Abstract
Photobiomodulation (PBM) therapy is a promising therapeutic approach for several pathologies, including stroke. The biological effects of PBM for the treatment of cerebral ischemia have previously been explored as a neuroprotective strategy using different light sources, wavelengths, and incident light powers. However, the capability of PBM as a novel alternative therapy to stimulate the recovery of the injured neuronal tissue after ischemic stroke has been poorly explored. The aim of this study was to investigate the low-level light irradiation therapy by using Light Emitting Diodes (LEDs) as potential therapeutic strategy for stroke. The LED photobiomodulation (continuous wave, 830 nm, 0.2–0.6 J/cm2) was firstly evaluated at different energy densities in C17.2 immortalized mouse neural progenitor cell lines, in order to observe if this treatment had any effect on cells, in terms of proliferation and viability. Then, the PBM-LED effect (continuous wave, 830 nm, 0.28 J/cm2 at brain cortex) on long-term recovery (12 weeks) was analyzed in ischemic animal model by means lesion reduction, behavioral deficits, and functional magnetic resonance imaging (fMRI). Analysis of cellular proliferation after PBM was significantly increased (1 mW) in all different exposure times used; however, this effect could not be replicated in vivo experimental conditions, as PBM did not show an infarct reduction or functional recovery. Despite the promising therapeutic effect described for PBM, further preclinical studies are necessary to optimize the therapeutic window of this novel therapy, in terms of the mechanism associated to neurorecovery and to reduce the risk of failure in futures clinical trials.
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Affiliation(s)
- Bárbara Argibay
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Francisco Campos
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - María Perez-Mato
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Alba Vieites-Prado
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Clara Correa-Paz
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Esteban López-Arias
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Andrés Da Silva-Candal
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Vicente Moreno
- Optics Area, Department of Applied Physics, Faculty of Physics, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain.,Faculty of Optics and Optometry, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Carlos Montero
- Optics Area, Department of Applied Physics, Faculty of Physics, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain.,Faculty of Optics and Optometry, Universitdade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Tomás Sobrino
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - José Castillo
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - Ramón Iglesias-Rey
- Clinical Neurosciences Research Laboratory, Health Research Institute of Santiago de Compostela (IDIS), Clinical University Hospital, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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18
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Buscemi L, Price M, Bezzi P, Hirt L. Spatio-temporal overview of neuroinflammation in an experimental mouse stroke model. Sci Rep 2019; 9:507. [PMID: 30679481 PMCID: PMC6345915 DOI: 10.1038/s41598-018-36598-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/21/2018] [Indexed: 12/18/2022] Open
Abstract
After ischemic stroke, in the lesion core as well as in the ischemic penumbra, evolution of tissue damage and repair is strongly affected by neuroinflammatory events that involve activation of local specialized glial cells, release of inflammatory mediators, recruiting of systemic cells and vascular remodelling. To take advantage of this intricate response in the quest to devise new protective therapeutic strategies we need a better understanding of the territorial and temporal interplay between stroke-triggered inflammatory and cell death-inducing processes in both parenchymal and vascular brain cells. Our goal is to describe structural rearrangements and functional modifications occurring in glial and vascular cells early after an acute ischemic stroke. Low and high scale mapping of the glial activation on brain sections of mice subjected to 30 minutes middle cerebral artery occlusion (MCAO) was correlated with that of the neuronal cell death, with markers for microvascular changes and with markers for pro-inflammatory (IL-1β) and reparative (TGFβ1) cytokines. Our results illustrate a time-course of the neuroinflammatory response starting at early time-points (1 h) and up to one week after MCAO injury in mice, with an accurate spatial distribution of the observed phenomena.
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Affiliation(s)
- Lara Buscemi
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011, Lausanne, Switzerland. .,Department of Fundamental Neurosciences, University of Lausanne, CH-1005, Lausanne, Switzerland.
| | - Melanie Price
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, CH-1005, Lausanne, Switzerland
| | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, CH-1005, Lausanne, Switzerland
| | - Lorenz Hirt
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011, Lausanne, Switzerland.,Department of Fundamental Neurosciences, University of Lausanne, CH-1005, Lausanne, Switzerland
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19
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Duricki DA, Drndarski S, Bernanos M, Wood T, Bosch K, Chen Q, Shine HD, Simmons C, Williams SCR, McMahon SB, Begley DJ, Cash D, Moon LDF. Stroke Recovery in Rats after 24-Hour-Delayed Intramuscular Neurotrophin-3 Infusion. Ann Neurol 2018; 85:32-46. [PMID: 30525223 PMCID: PMC6492080 DOI: 10.1002/ana.25386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 11/28/2018] [Accepted: 11/28/2018] [Indexed: 12/30/2022]
Abstract
Objective Neurotrophin‐3 (NT3) plays a key role in the development and function of locomotor circuits including descending serotonergic and corticospinal tract axons and afferents from muscle and skin. We have previously shown that gene therapy delivery of human NT3 into affected forelimb muscles improves sensorimotor recovery after stroke in adult and elderly rats. Here, to move toward the clinic, we tested the hypothesis that intramuscular infusion of NT3 protein could improve sensorimotor recovery after stroke. Methods Rats received unilateral ischemic stroke in sensorimotor cortex. To simulate a clinically feasible time to treatment, 24 hours later rats were randomized to receive NT3 or vehicle by infusion into affected triceps brachii for 4 weeks using implanted catheters and minipumps. Results Radiolabeled NT3 crossed from the bloodstream into the brain and spinal cord in rodents with or without strokes. NT3 increased the accuracy of forelimb placement during walking on a horizontal ladder and increased use of the affected arm for lateral support during rearing. NT3 also reversed sensory impairment of the affected wrist. Functional magnetic resonance imaging during stimulation of the affected wrist showed spontaneous recovery of peri‐infarct blood oxygenation level–dependent signal that NT3 did not further enhance. Rather, NT3 induced neuroplasticity of the spared corticospinal and serotonergic pathways. Interpretation Our results show that delayed, peripheral infusion of NT3 can improve sensorimotor function after ischemic stroke. Phase I and II clinical trials of NT3 (for constipation and neuropathy) have shown that peripheral high doses are safe and well tolerated, which paves the way for NT3 as a therapy for stroke. ANN NEUROL 2019;85:32–46.
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Affiliation(s)
- Denise A Duricki
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom.,Centre for Integrative Biology, King's College London, London, United Kingdom
| | - Svetlana Drndarski
- Blood-Brain Barrier Group, Institute of Pharmaceutical Science, King's College London, London, United Kingdom
| | - Michel Bernanos
- Neuroimaging Research Group, King's College London, London, United Kingdom
| | - Tobias Wood
- Neuroimaging Research Group, King's College London, London, United Kingdom
| | - Karen Bosch
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Qin Chen
- Center for Cell and Gene Therapy, Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - H David Shine
- Center for Cell and Gene Therapy, Department of Neuroscience, Baylor College of Medicine, Houston, TX
| | - Camilla Simmons
- Neuroimaging Research Group, King's College London, London, United Kingdom
| | | | - Stephen B McMahon
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - David J Begley
- Blood-Brain Barrier Group, Institute of Pharmaceutical Science, King's College London, London, United Kingdom
| | - Diana Cash
- Neuroimaging Research Group, King's College London, London, United Kingdom
| | - Lawrence D F Moon
- Neurorestoration Group, Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom.,Centre for Integrative Biology, King's College London, London, United Kingdom
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20
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Brunner C, Korostelev M, Raja S, Montaldo G, Urban A, Baron JC. Evidence from functional ultrasound imaging of enhanced contralesional microvascular response to somatosensory stimulation in acute middle cerebral artery occlusion/reperfusion in rats: A marker of ultra-early network reorganization? J Cereb Blood Flow Metab 2018; 38:1690-1700. [PMID: 29972329 PMCID: PMC6168914 DOI: 10.1177/0271678x18786359] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Following middle cerebral artery (MCA) stroke, enhanced contralesional evoked responses have been consistently reported both in man and rodents as part of plastic processes thought to influence motor recovery. How early this marker of large-scale network reorganization develops has however been little addressed, yet has clinical relevance for rehabilitation strategies targeting plasticity. Previous work in mice has reported enhanced contralesional responses to unaffected-side forepaw stimulation as early as 45 min after MCA small branch occlusion. Using functional ultrasound imaging (fUSi) in anesthetized rats subjected to distal temporary MCA occlusion (MCAo), we assessed here (i) whether enhanced contralesional responses also occurred with unaffected-side whisker pad stimulation, and if so, how early after MCAo; and (ii) the time course of this abnormal response during occlusion and after reperfusion. We replicate in a more proximal MCA occlusion model the earlier findings of ultra-early enhanced contralesional evoked responses. In addition, we document this phenomenon within minutes after MCAo, and its persistence throughout the entire 90-min occlusion as well as 90-min reperfusion periods studied. These findings suggest that plastic processes may start within minutes following MCAo in rodents. If replicated in man, they might have implications regarding how early plasticity-enhancing therapies can be initiated after stroke.
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Affiliation(s)
- Clément Brunner
- 1 Inserm U894, Université Paris Descartes, Paris, France.,2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | | | - Sushmitha Raja
- 1 Inserm U894, Université Paris Descartes, Paris, France
| | - Gabriel Montaldo
- 2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | - Alan Urban
- 2 Neuro-Electronics Research Flanders (NERF; A Research Initiative by IMEC, VIB and KU Leuven), Catholic University Leuven, Leuven, Belgium
| | - Jean-Claude Baron
- 1 Inserm U894, Université Paris Descartes, Paris, France.,3 Department of Neurology, Hôpital Sainte-Anne, Paris, France
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21
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Chao THH, Chen JH, Yen CT. Plasticity changes in forebrain activity and functional connectivity during neuropathic pain development in rats with sciatic spared nerve injury. Mol Brain 2018; 11:55. [PMID: 30285801 PMCID: PMC6167811 DOI: 10.1186/s13041-018-0398-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 09/20/2018] [Indexed: 01/08/2023] Open
Abstract
Neuropathic pain is a major worldwide health problem. Although central sensitization has been reported in well-established neuropathic conditions, information on the acute brain activation patterns in response to peripheral nerve injury is lacking. This study first mapped the brain activity in rats immediately following spared nerve injury (SNI) of the sciatic nerve. Using blood-oxygenation-level-dependent functional magnetic resonance imaging (BOLD-fMRI), we observed sustained activation in the bilateral insular cortices (ICs), primary somatosensory cortex (S1), and cingulate cortex. Second, this study sought to link this sustained activation pattern with brain sensitization. Using manganese-enhanced magnetic resonance imaging (MEMRI), we observed enhanced activity in the ipsilateral anterior IC (AIC) in free-moving SNI rats on Days 1 and 8 post-SNI. Furthermore, enhanced functional connectivity between the ipsilateral AIC, bilateral rostral AIC, and S1 was observed on Day 8 post-SNI. Chronic electrophysiological recording experiments were conducted to confirm the tonic neuronal activation in selected brain regions. Our data provide evidence of tonic activation-dependent brain sensitization during neuropathic pain development and offer evidence that the plasticity changes in the IC and S1 may contribute to neuropathic pain development.
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Affiliation(s)
- Tzu-Hao Harry Chao
- Department of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Jyh-Horng Chen
- Interdisciplinary MRI/MRS Lab, Department of Electrical Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 10617, Taiwan
| | - Chen-Tung Yen
- Department of Life Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Rd, Taipei, 10617, Taiwan.
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22
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Lake EMR, Bazzigaluppi P, Stefanovic B. Functional magnetic resonance imaging in chronic ischaemic stroke. Philos Trans R Soc Lond B Biol Sci 2017; 371:rstb.2015.0353. [PMID: 27574307 DOI: 10.1098/rstb.2015.0353] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 11/12/2022] Open
Abstract
Ischaemic stroke is the leading cause of adult disability worldwide. Effective rehabilitation is hindered by uncertainty surrounding the underlying mechanisms that govern long-term ischaemic injury progression. Despite its potential as a sensitive non-invasive in vivo marker of brain function that may aid in the development of new treatments, blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI) has found limited application in the clinical research on chronic stage stroke progression. Stroke affects each of the physiological parameters underlying the BOLD contrast, markedly complicating the interpretation of BOLD fMRI data. This review summarizes current progress on application of BOLD fMRI in the chronic stage of ischaemic injury progression and discusses means by which more information may be gained from such BOLD fMRI measurements. Concomitant measurements of vascular reactivity, neuronal activity and metabolism in preclinical models of stroke are reviewed along with illustrative examples of post-ischaemic evolution in neuronal, glial and vascular function. The realization of the BOLD fMRI potential to propel stroke research is predicated on the carefully designed preclinical research establishing an ischaemia-specific quantitative model of BOLD signal contrast to provide the framework for interpretation of fMRI findings in clinical populations.This article is part of the themed issue 'Interpreting BOLD: a dialogue between cognitive and cellular neuroscience'.
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Affiliation(s)
- Evelyn M R Lake
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
| | - Paolo Bazzigaluppi
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada Fundamental Neurobiology, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Bojana Stefanovic
- Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada Physical Sciences Platform, Sunnybrook Research Institute, Toronto, Ontario, Canada Heart and Stroke Foundation Centre for Stroke Recovery, Ottawa, Canada
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23
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Zhong YH, Dhawan J, Kovoor JA, Sullivan J, Zhang WX, Choi D, Biegon A. Aromatase and neuroinflammation in rat focal brain ischemia. J Steroid Biochem Mol Biol 2017; 174:225-233. [PMID: 28964927 DOI: 10.1016/j.jsbmb.2017.09.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 09/24/2017] [Accepted: 09/25/2017] [Indexed: 12/22/2022]
Abstract
Accumulating evidence suggests that expression of aromatase, the enzyme responsible for the conversion of androgens to estrogens, is transiently upregulated in rat stroke models. It was further suggested that increased aromatase expression is linked to neuroinflammation and that it is neuroprotective in females. Our goal was to investigate aromatase upregulation in male rats subjected to experimental stroke in relationship to neuroinflammation, infarct and response to treatment with different putative neuroprotective agents. Intact male rats were subjected to transient (90min) middle cerebral artery occlusion (MCAO) and administered selfotel (N-methyl-d-aspartic acid (NMDA) receptor competitive antagonist), TPEN (a zinc chelator), a combination of the two drugs or vehicle, injected immediately after reperfusion. Animals were killed 14days after MCAO and consecutive brain sections used to measure aromatase expression, cerebral infarct volume and neuroinflammation. Quantitative immunohistochemistry (IHC) demonstrated increased brain aromatase expression in the peri-infarct area relative to contralesional area, which was partially abrogated by neuroprotective agents. There was no correlation between aromatase expression in the peri-infarct zone and infarct volume, which was reduced by neuroprotective agents. Microglial activation, measured by quantitative autoradiography, was positively correlated with infarct and inversely correlated with aromatase expression in the peri-infarct zone. Our findings indicate that focal ischemia upregulates brain aromatase in the male rat brain at 14days post surgery, which is within the time frame documented in females. However, the lack of negative correlation between aromatase expression and infarct volume and lack of positive correlation between microgliosis and aromatase do not support a major role for aromatase as a mediator of neuroprotection or a causal relationship between microglial activation and increased aromatase expression in male focal ischemia.
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Affiliation(s)
- Yu H Zhong
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, Guangdong Province 510080, PR China; Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Jasbeer Dhawan
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Joel A Kovoor
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - John Sullivan
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Wei X Zhang
- Department of Neurology, the First Affiliated Hospital of Sun Yat-Sen University, No. 58, Zhongshan Road II, Guangzhou, Guangdong Province 510080, PR China.
| | - Dennis Choi
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
| | - Anat Biegon
- Department of Neurology, Stony Brook University, 100 Nicolls Road, Stony Brook, NY 11794-2565, USA.
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24
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Shim WH, Suh JY, Kim JK, Jeong J, Kim YR. Enhanced Thalamic Functional Connectivity with No fMRI Responses to Affected Forelimb Stimulation in Stroke-Recovered Rats. Front Neural Circuits 2017; 10:113. [PMID: 28119575 PMCID: PMC5222821 DOI: 10.3389/fncir.2016.00113] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 12/21/2016] [Indexed: 01/21/2023] Open
Abstract
Neurological recovery after stroke has been extensively investigated to provide better understanding of neurobiological mechanism, therapy, and patient management. Recent advances in neuroimaging techniques, particularly functional MRI (fMRI), have widely contributed to unravel the relationship between the altered neural function and stroke-affected brain areas. As results of previous investigations, the plastic reorganization and/or gradual restoration of the hemodynamic fMRI responses to neural stimuli have been suggested as relevant mechanisms underlying the stroke recovery process. However, divergent study results and modality-dependent outcomes have clouded the proper interpretation of variable fMRI signals. Here, we performed both evoked and resting state fMRI (rs-fMRI) to clarify the link between the fMRI phenotypes and post-stroke functional recovery. The experiments were designed to examine the altered neural activity within the contra-lesional hemisphere and other undamaged brain regions using rat models with large unilateral stroke, which despite the severe injury, exhibited nearly full recovery at ∼6 months after stroke. Surprisingly, both blood oxygenation level-dependent and blood volume-weighted (CBVw) fMRI activities elicited by electrical stimulation of the stroke-affected forelimb were completely absent, failing to reveal the neural origin of the behavioral recovery. In contrast, the functional connectivity maps showed highly robust rs-fMRI activity concentrated in the contra-lesional ventromedial nucleus of thalamus (VM). The negative finding in the stimuli-induced fMRI study using the popular rat middle cerebral artery model denotes weak association between the fMRI hemodynamic responses and neurological improvement. The results strongly caution the indiscreet interpretation of stroke-affected fMRI signals and demonstrate rs-fMRI as a complementary tool for efficiently characterizing stroke recovery.
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Affiliation(s)
- Woo H Shim
- Department of Radiology, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; ASAN Institute for Life Sciences, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; Department of Bio and Brain Engineering, Korea Advanced Institute of Science and TechnologyDaejeon, South Korea; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, BostonMA, USA
| | - Ji-Yeon Suh
- Department of Radiology, ASAN Medical Center, University of Ulsan College of MedicineUlsan, South Korea; Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, BostonMA, USA
| | - Jeong K Kim
- Department of Radiology, ASAN Medical Center, University of Ulsan College of Medicine Ulsan, South Korea
| | - Jaeseung Jeong
- Department of Bio and Brain Engineering, Korea Advanced Institute of Science and Technology Daejeon, South Korea
| | - Young R Kim
- Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston MA, USA
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25
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Liu J, Duffy BA, Bernal-Casas D, Fang Z, Lee JH. Comparison of fMRI analysis methods for heterogeneous BOLD responses in block design studies. Neuroimage 2016; 147:390-408. [PMID: 27993672 DOI: 10.1016/j.neuroimage.2016.12.045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/19/2016] [Accepted: 12/15/2016] [Indexed: 01/22/2023] Open
Abstract
A large number of fMRI studies have shown that the temporal dynamics of evoked BOLD responses can be highly heterogeneous. Failing to model heterogeneous responses in statistical analysis can lead to significant errors in signal detection and characterization and alter the neurobiological interpretation. However, to date it is not clear that, out of a large number of options, which methods are robust against variability in the temporal dynamics of BOLD responses in block-design studies. Here, we used rodent optogenetic fMRI data with heterogeneous BOLD responses and simulations guided by experimental data as a means to investigate different analysis methods' performance against heterogeneous BOLD responses. Evaluations are carried out within the general linear model (GLM) framework and consist of standard basis sets as well as independent component analysis (ICA). Analyses show that, in the presence of heterogeneous BOLD responses, conventionally used GLM with a canonical basis set leads to considerable errors in the detection and characterization of BOLD responses. Our results suggest that the 3rd and 4th order gamma basis sets, the 7th to 9th order finite impulse response (FIR) basis sets, the 5th to 9th order B-spline basis sets, and the 2nd to 5th order Fourier basis sets are optimal for good balance between detection and characterization, while the 1st order Fourier basis set (coherence analysis) used in our earlier studies show good detection capability. ICA has mostly good detection and characterization capabilities, but detects a large volume of spurious activation with the control fMRI data.
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Affiliation(s)
- Jia Liu
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Ben A Duffy
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - David Bernal-Casas
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA
| | - Zhongnan Fang
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA.,Department of Electrical Engineering, Stanford University, Stanford, CA 94305
| | - Jin Hyung Lee
- Department of Neurology & Neurological Sciences, Stanford University, Stanford, CA 94305, USA.,Department of Electrical Engineering, Stanford University, Stanford, CA 94305.,Department of Bioengineering, Stanford University, Stanford, CA 94305, USA.,Department of Neurosurgery, Stanford University, Stanford, CA 94305, USA
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26
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Cha J, Kim ST, Jung WB, Han YH, Im GH, Lee JH. Altered white matter integrity and functional connectivity of hyperacute-stage cerebral ischemia in a rat model. Magn Reson Imaging 2016; 34:1189-98. [DOI: 10.1016/j.mri.2016.04.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Accepted: 04/17/2016] [Indexed: 11/28/2022]
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27
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Mandeville ET, Ayata C, Zheng Y, Mandeville JB. Translational MR Neuroimaging of Stroke and Recovery. Transl Stroke Res 2016; 8:22-32. [PMID: 27578048 DOI: 10.1007/s12975-016-0497-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 12/26/2022]
Abstract
Multiparametric magnetic resonance imaging (MRI) has become a critical clinical tool for diagnosing focal ischemic stroke severity, staging treatment, and predicting outcome. Imaging during the acute phase focuses on tissue viability in the stroke vicinity, while imaging during recovery requires the evaluation of distributed structural and functional connectivity. Preclinical MRI of experimental stroke models provides validation of non-invasive biomarkers in terms of cellular and molecular mechanisms, while also providing a translational platform for evaluation of prospective therapies. This brief review of translational stroke imaging discusses the acute to chronic imaging transition, the principles underlying common MRI methods employed in stroke research, and the experimental results obtained by clinical and preclinical imaging to determine tissue viability, vascular remodeling, structural connectivity of major white matter tracts, and functional connectivity using task-based and resting-state fMRI during the stroke recovery process.
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Affiliation(s)
- Emiri T Mandeville
- Neuroprotection Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA. .,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA.
| | - Cenk Ayata
- Neurovascular Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
| | - Yi Zheng
- Neurovascular Research Laboratory, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
| | - Joseph B Mandeville
- Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.,Department of Radiology, Massachusetts General Hospital, Bldg 149 13th Street, Charlestown, MA, 02129, USA
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28
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Gervois P, Wolfs E, Ratajczak J, Dillen Y, Vangansewinkel T, Hilkens P, Bronckaers A, Lambrichts I, Struys T. Stem Cell-Based Therapies for Ischemic Stroke: Preclinical Results and the Potential of Imaging-Assisted Evaluation of Donor Cell Fate and Mechanisms of Brain Regeneration. Med Res Rev 2016; 36:1080-1126. [DOI: 10.1002/med.21400] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Revised: 05/27/2016] [Accepted: 06/17/2016] [Indexed: 12/15/2022]
Affiliation(s)
- Pascal Gervois
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Esther Wolfs
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Jessica Ratajczak
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Yörg Dillen
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Tim Vangansewinkel
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Petra Hilkens
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Annelies Bronckaers
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Ivo Lambrichts
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
| | - Tom Struys
- Morphology Research Group, Biomedical Research Institute, Hasselt University; Campus Diepenbeek; Bioville Diepenbeek Belgium
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29
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Barios JA, Pisarchyk L, Fernandez-Garcia L, Barrio LC, Ramos M, Martinez-Murillo R, Gonzalez-Nieto D. Long-term dynamics of somatosensory activity in a stroke model of distal middle cerebral artery oclussion. J Cereb Blood Flow Metab 2016; 36:606-20. [PMID: 26661150 PMCID: PMC4794092 DOI: 10.1177/0271678x15606139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 07/28/2015] [Indexed: 11/17/2022]
Abstract
A constant challenge in experimental stroke is the use of appropriate tests to identify signs of recovery and adverse effects linked to a particular therapy. In this study, we used a long-term longitudinal approach to examine the functional brain changes associated with cortical infarction in a mouse model induced by permanent ligation of the middle cerebral artery (MCA). Sensorimotor function and somatosensory cortical activity were evaluated with fault-foot and forelimb asymmetry tests in combination with somatosensory evoked potentials. The stroke mice exhibited both long-term deficits in the functional tests and impaired responses in the infarcted and intact hemispheres after contralateral and ipsilateral forepaw stimulation. In the infarcted hemisphere, reductions in the amplitudes of evoked responses were detected after contralateral and ipsilateral stimulation. In the intact hemisphere, and similar to cortical stroke patients, a gradual hyperexcitability was observed after contralateral stimulation but no parallel evidence of a response was detected after ipsilateral stimulation. Our results suggest the existence of profound and persistent changes in the somatosensory cortex in this specific mouse cortical stroke model. The study of evoked potentials constitutes a feasible and excellent tool for evaluating the fitness of the somatosensory cortex in relation to functional recovery after preclinical therapeutic intervention.
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Affiliation(s)
- Juan A Barios
- Unit of Cellular and Animal models, Experimental Neurology Laboratory, Center for Biomedical Technology, Universidad Politécnica, Madrid, Spain
| | - Liudmila Pisarchyk
- Unit of Cellular and Animal models, Experimental Neurology Laboratory, Center for Biomedical Technology, Universidad Politécnica, Madrid, Spain
| | - Laura Fernandez-Garcia
- Unit of Cellular and Animal models, Experimental Neurology Laboratory, Center for Biomedical Technology, Universidad Politécnica, Madrid, Spain
| | - Luis C Barrio
- Unit of Experimental Neurology, Hospital Universitario Ramón y Cajal-IRYCIS, Madrid, Spain
| | - Milagros Ramos
- Unit of Cellular and Animal models, Experimental Neurology Laboratory, Center for Biomedical Technology, Universidad Politécnica, Madrid, Spain Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
| | - Ricardo Martinez-Murillo
- Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal (CSIC), Madrid, Spain
| | - Daniel Gonzalez-Nieto
- Unit of Cellular and Animal models, Experimental Neurology Laboratory, Center for Biomedical Technology, Universidad Politécnica, Madrid, Spain Biomedical Research Networking Center in Bioengineering Biomaterials and Nanomedicine (CIBER-BBN), Madrid, Spain
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30
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Rosenberg JT, Shemesh N, Muniz JA, Dumez JN, Frydman L, Grant SC. Transverse relaxation of selectively excited metabolites in stroke at 21.1 T. Magn Reson Med 2016; 77:520-528. [PMID: 26834031 DOI: 10.1002/mrm.26132] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 12/11/2015] [Accepted: 12/27/2015] [Indexed: 12/21/2022]
Abstract
PURPOSE This study seeks to evaluate in vivo T2 relaxation times of selectively excited stroke-relevant metabolites via 1 H relaxation-enhanced magnetic resonance spectroscopy (RE-MRS) at 21.1 T (900 MHz). METHODS A quadrature surface coil was designed and optimized for investigations of rodents at 21.1 T. With voxel localization, a RE-MRS pulse sequence incorporating the excitation of selected metabolites was modified to include a variable echo delay for T2 measurements. A middle cerebral artery occlusion (MCAO) animal model for stroke was examined with spectra taken 24 h post occlusion. Fourteen echo times were acquired, with each measurement completed in less than 2 min. RESULTS The RE-MRS approach produced high-quality spectra of the selectively excited metabolites in the stroked and contralateral regions. T2 measurements reveal differential results between these regions, with significance achieved for lactic acid. CONCLUSION Using the RE-MRS technique at ultra-high magnetic field and an optimized quadrature surface coil design, full metabolic T2 quantifications in a localized voxel is now possible in less than 27 min. Magn Reson Med 77:520-528, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Jens T Rosenberg
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA
| | - Noam Shemesh
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Jose A Muniz
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.,Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
| | - Jean-Nicolas Dumez
- French National Centre for Scientific Research, Institute de Chime des Substances Naturelles, Gif-sur-Yvette, France
| | - Lucio Frydman
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.,Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Samuel C Grant
- The National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida, USA.,Department of Chemical & Biomedical Engineering, FAMU-FSU College of Engineering, Florida State University, Tallahassee, Florida, USA
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31
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Liao LD, Li ML, Lai HY, Chen YY, Thakor NV. Study of neurovascular coupling functions for transient focal cerebral ischemia in rats using electrocorticography functional photoacoustic microscopy (ECoG-fPAM). ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2015; 2013:1799-802. [PMID: 24110058 DOI: 10.1109/embc.2013.6609871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Recently, the functional photoacoustic microscopy (fPAM) system has been proven to be a reliable imaging technique for measuring the total hemoglobin concentration (HbT), cerebral blood volume (CBV) and hemoglobin oxygen saturation (SO2) in single cerebral blood vessels of rats. In this study, we report for the first time the combination of electrocorticography (ECoG) recordings and fPAM (ECoG-fPAM) to investigate functional hemodynamic changes and neuro-vascular coupling in single cortical arterioles of rats with electrical forepaw stimulation after photothrombotic stroke. Because of the optical focusing nature of our fPAM system, photo-induced ischemic stroke targeting on single cortical arterioles can be easily conducted with simple adaptation. Functional cerebral HbT, CBV and SO2 changes associated with the induced stroke in selected arterioles from the anterior cerebral artery system were imaged with a 36 × 65-µm spatial resolution. The ECoG-fPAM system complements existing imaging techniques and has the potential to offer a favorable tool for explicitly studying cerebral hemodynamics and neuro-vascular coupling in small animal models of photo-induced ischemic stroke.
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32
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Li C, Li Z, Ward BD, Dwinell MR, Lombard JH, Hudetz AG, Pawela CP. Enhancement of resting-state fcMRI networks by prior sensory stimulation. Brain Connect 2015; 4:760-8. [PMID: 25387238 DOI: 10.1089/brain.2014.0326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It is important to consider the effect of a previous experimental condition when analyzing resting-state functional connectivity magnetic resonance imaging (fcMRI) data. In this work, a simple sensory stimulation functional MRI (fMRI) experiment was conducted between two resting-state fcMRI acquisitions in anesthetized rats using a high-field small-animal MR scanner. Previous human studies have reported fcMRI network alteration by prior task/stimulus utilizing similar experimental paradigms. An anesthetized rat preparation was used to test whether brain regions with higher level functions are involved in post-task/stimulus fcMRI network alteration. We demonstrate significant fcMRI enhancement poststimulation in the sensory cortical, limbic, and insular brain regions in rats. These brain regions have been previously implicated in vigilance and anesthetic arousal networks. We tested their experimental paradigm in several inbred strains of rats with known phenotypic differences in anesthetic susceptibility and cerebral vascular function. Brown Norway (BN), Dahl Salt-Sensitive (SS), and consomic SSBN13 strains were tested. We have previously shown significant differences in blood oxygen level-dependent fMRI activity and fcMRI networks across these strains. Here we report statistically significant interstrain differences in regional fcMRI poststimulation enhancement. In the SS strain, poststimulation enhancement occurred in posterior sensory and limbic cortical brain regions. In the BN strain, poststimulation enhancement appeared in anterior cingulate and subcortical limbic brain regions. These results imply that a prior condition has a significant impact on fcMRI networks that depend on intersubject difference in genetics and physiology.
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Affiliation(s)
- Chenxuan Li
- 1 Department of Plastic Surgery, Medical College of Wisconsin , Milwaukee, Wisconsin
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Ganguly K, Byl NN, Abrams GM. Neurorehabilitation: motor recovery after stroke as an example. Ann Neurol 2015; 74:373-81. [PMID: 25813243 DOI: 10.1002/ana.23994] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 07/31/2013] [Accepted: 07/31/2013] [Indexed: 12/13/2022]
Abstract
The field of neurorehabilitation aims to translate neuroscience research toward the goal of maximizing functional recovery after neurological injury. A growing body of research indicates that the fundamental principles of neurological rehabilitation are applicable to a broad range of congenital, degenerative, and acquired neurological disorders. In this perspective, we will focus on motor recovery after acquired brain injuries such as stroke. Over the past few decades, a large body of basic and clinical research has created an experimental and theoretical foundation for approaches to neurorehabilitation. Recent randomized clinical trials all emphasize the requirement for intense progressive rehabilitation programs to optimally enhance recovery. Moreover, advances in multimodal assessment of patients with neuroimaging and neurophysiological tools suggest the possibility of individualized treatment plans based on recovery potential. There are also promising indications for medical as well as noninvasive brain stimulation paradigms to facilitate recovery. Ongoing or planned clinical studies should provide more definitive evidence. We also highlight unmet needs and potential areas of research. Continued research built upon a robust experimental and theoretical foundation should help to develop novel treatments to improve recovery after neurological injury.
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Affiliation(s)
- Karunesh Ganguly
- Department of Neurology and Rehabilitation, San Francisco Veterans Administration Medical Center, University of California, San Francisco, San Francisco, CA; Departments of Neurology, University of California, San Francisco, San Francisco, CA
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Shemesh N, Rosenberg JT, Dumez JN, Grant SC, Frydman L. Metabolic T1 dynamics and longitudinal relaxation enhancement in vivo at ultrahigh magnetic fields on ischemia. J Cereb Blood Flow Metab 2014; 34:1810-7. [PMID: 25204392 PMCID: PMC4269758 DOI: 10.1038/jcbfm.2014.149] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 07/25/2014] [Accepted: 07/28/2014] [Indexed: 01/02/2023]
Abstract
Interruptions in cerebral blood flow may lead to devastating neural outcomes. Magnetic resonance has a central role in diagnosing and monitoring these insufficiencies, as well as in understanding their underlying metabolic consequences. Magnetic resonance spectroscopy (MRS) in particular can probe ischemia via the signatures of endogenous metabolites including lactic acid (Lac), N-acetylaspartate, creatine (Cre), and cholines. Typically, MRS reports on these metabolites' concentrations. This study focuses on establishing the potential occurrence of in vivo longitudinal relaxation enhancement (LRE) effects-a phenomenon involving a reduction of the apparent T1 with selective bandwidth excitations- in a rat stroke model at 21.1 T. Statistically significant reductions in Cre's apparent T1s were observed at all the examined post-ischemia time points for both ipsi- and contralateral hemispheres, thereby establishing the existence of LREs for this metabolite in vivo. Ischemia-dependent LRE trends were also noted for Lac in the ipsilateral hemisphere only 24 hours after ischemia. Metabolic T1s were also found to vary significantly as a function of post-stroke recovery time, with the most remarkable and rapid changes observed for Lac T1s. The potential of such measurements to understand stroke at a molecular level and assist in its diagnosis, is discussed.
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Affiliation(s)
- Noam Shemesh
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Jens T Rosenberg
- 1] National High Magnetic Field Laboratory, The Florida State University, Tallahassee, Florida, USA [2] Chemical & Biomedical Engineering, The Florida State University, Tallahassee, Florida, USA
| | - Jean-Nicolas Dumez
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Samuel C Grant
- 1] National High Magnetic Field Laboratory, The Florida State University, Tallahassee, Florida, USA [2] Chemical & Biomedical Engineering, The Florida State University, Tallahassee, Florida, USA
| | - Lucio Frydman
- 1] Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel [2] National High Magnetic Field Laboratory, The Florida State University, Tallahassee, Florida, USA
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Imaging neurovascular function and functional recovery after stroke in the rat striatum using forepaw stimulation. J Cereb Blood Flow Metab 2014; 34:1483-92. [PMID: 24917039 PMCID: PMC4158660 DOI: 10.1038/jcbfm.2014.103] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 05/05/2014] [Accepted: 05/07/2014] [Indexed: 12/19/2022]
Abstract
Negative functional magnetic resonance imaging (fMRI) response in the striatum has been observed in several studies during peripheral sensory stimulation, but its relationship between local field potential (LFP) remains to be elucidated. We performed cerebral blood volume (CBV) fMRI and LFP recordings in normal rats during graded noxious forepaw stimulation at nine stimulus pulse widths. Albeit high LFP-CBV correlation was found in the ipsilateral and contralateral sensory cortices (r=0.89 and 0.95, respectively), the striatal CBV responses were neither positively, nor negatively correlated with LFP (r=0.04), demonstrating that the negative striatal CBV response is not originated from net regional inhibition. To further identify whether this negative CBV response can serve as a marker for striatal functional recovery, two groups of rats (n=5 each) underwent 20- and 45-minute middle cerebral artery occlusion (MCAO) were studied. No CBV response was found in the ipsilateral striatum in both groups immediately after stroke. Improved striatal CBV response was observed on day 28 in the 20-minute MCAO group compared with the 45-minute MCAO group (P<0.05). This study shows that fMRI signals could differ significantly from LFP and that the observed negative CBV response has potential to serve as a marker for striatal functional integrity in rats.
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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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Kim HS, Kim D, Kim RG, Kim JM, Chung E, Neto PR, Lee MC, Kim HI. A rat model of photothrombotic capsular infarct with a marked motor deficit: a behavioral, histologic, and microPET study. J Cereb Blood Flow Metab 2014; 34:683-9. [PMID: 24473479 PMCID: PMC3982097 DOI: 10.1038/jcbfm.2014.2] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 12/11/2013] [Accepted: 12/30/2013] [Indexed: 01/05/2023]
Abstract
We present a new method for inducing a circumscribed subcortical capsular infarct (SCI), which imposes a persistent motor impairment in rats. Photothrombotic destruction of the internal capsule (IC) was conducted in Sprague Dawley rats (male; n=38). The motor performance of all animals was assessed using forelimb placing, forelimb use asymmetry, and the single pellet reaching test. On the basis of the degree of motor recovery, rats were subdivided into either the poor recovery group (PRG) or the moderate recovery group (MRG). Imaging assessment of the impact of SCI on brain metabolism was performed using 2-deoxy-2-[(18)F]-fluoro-D-glucose ([(18)F]-FDG) microPET (positron emission tomography). Photothrombotic lesioning using low light energy selectively disrupted circumscribed capsular fibers. The MRG showed recovery of motor performance after 1 week, but the PRG showed a persistent motor impairment for >3 weeks. Damage to the posterior limb of the IC (PLIC) is more effective for producing a severe motor deficit. Analysis of PET data revealed decreased regional glucose metabolism in the ipsilesional motor and bilateral sensory cortex and increased metabolism in the contralesional motor cortex and bilateral hippocampus during the early recovery period after SCI. Behavioral, histologic, and functional imaging findings support the usefulness of this novel SCI rat model for investigating motor recovery.
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Affiliation(s)
- Hyung-Sun Kim
- Department of Medical System Engineering & School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Donghyeon Kim
- School of Information and Communication, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Ra Gyung Kim
- Department of Medical System Engineering & School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Jin-Myung Kim
- Department of Medical System Engineering & School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Euiheon Chung
- Department of Medical System Engineering & School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea
| | - Pedro R Neto
- Translational Neuroimaging Laboratory, McGill Center for Studies in Aging, Douglas Mental Health University Institute, Montreal, Quebec, Canada
| | - Min-Cheol Lee
- Department of Pathology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Hyoung-Ihl Kim
- 1] Department of Medical System Engineering & School of Mechatronics, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea [2] Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Republic of Korea
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Grefkes C, Fink GR. Connectivity-based approaches in stroke and recovery of function. Lancet Neurol 2014; 13:206-16. [PMID: 24457190 DOI: 10.1016/s1474-4422(13)70264-3] [Citation(s) in RCA: 357] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
After focal damage, cerebral networks reorganise their structural and functional anatomy to compensate for both the lesion itself and remote effects. Novel developments in the analysis of functional neuroimaging data enable us to assess in vivo the specific contributions of individual brain areas to recovery of function and the effect of treatment on cortical reorganisation. Connectivity analyses can be used to investigate the effect of stroke on cerebral networks, and help us to understand why some patients make a better recovery than others. This systems-level view also provides insights into how neuromodulatory interventions might target pathological network configurations associated with incomplete recovery. In the future, such analyses of connectivity could help to optimise treatment regimens based on the individual network pathology underlying a particular neurological deficit, thereby opening the way for stratification of patients based on the possible response to an intervention.
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Affiliation(s)
- Christian Grefkes
- Department of Neurology, University Hospital Cologne, Köln, Germany; Neuromodulation and Neurorehabilitation, Max Planck Institute for Neurological Research, Köln, Germany; Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Jülich, Germany.
| | - Gereon R Fink
- Department of Neurology, University Hospital Cologne, Köln, Germany; Cognitive Neuroscience, Institute of Neuroscience and Medicine (INM-3), Research Centre Jülich, Jülich, Germany
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Canazza A, Minati L, Boffano C, Parati E, Binks S. Experimental models of brain ischemia: a review of techniques, magnetic resonance imaging, and investigational cell-based therapies. Front Neurol 2014; 5:19. [PMID: 24600434 PMCID: PMC3928567 DOI: 10.3389/fneur.2014.00019] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 02/06/2014] [Indexed: 01/17/2023] Open
Abstract
Stroke continues to be a significant cause of death and disability worldwide. Although major advances have been made in the past decades in prevention, treatment, and rehabilitation, enormous challenges remain in the way of translating new therapeutic approaches from bench to bedside. Thrombolysis, while routinely used for ischemic stroke, is only a viable option within a narrow time window. Recently, progress in stem cell biology has opened up avenues to therapeutic strategies aimed at supporting and replacing neural cells in infarcted areas. Realistic experimental animal models are crucial to understand the mechanisms of neuronal survival following ischemic brain injury and to develop therapeutic interventions. Current studies on experimental stroke therapies evaluate the efficiency of neuroprotective agents and cell-based approaches using primarily rodent models of permanent or transient focal cerebral ischemia. In parallel, advancements in imaging techniques permit better mapping of the spatial-temporal evolution of the lesioned cortex and its functional responses. This review provides a condensed conceptual review of the state of the art of this field, from models and magnetic resonance imaging techniques through to stem cell therapies.
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Affiliation(s)
- Alessandra Canazza
- Cerebrovascular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan , Italy
| | - Ludovico Minati
- Scientific Department, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan , Italy ; Brighton and Sussex Medical School , Brighton , UK
| | - Carlo Boffano
- Neuroradiology Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan , Italy
| | - Eugenio Parati
- Cerebrovascular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta" , Milan , Italy
| | - Sophie Binks
- Brighton and Sussex Medical School , Brighton , UK ; Brighton and Sussex University Hospitals NHS Trust , Brighton , UK
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Tennant KA. Thinking outside the brain: structural plasticity in the spinal cord promotes recovery from cortical stroke. Exp Neurol 2014; 254:195-9. [PMID: 24518486 DOI: 10.1016/j.expneurol.2014.02.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 02/02/2014] [Indexed: 11/29/2022]
Abstract
Neuroanatomically connected regions distal to a cortical stroke can exhibit both degenerative and adaptive changes during recovery. As the locus for afferent somatosensory fibres and efferent motor fibres, the spinal cord is ideally situated to play a critical role in functional recovery. In contrast to the wealth of research into cortical plasticity after stroke, much less focus has previously been placed on the role of subcortical or spinal cord plasticity in recovery of function after cortical stroke. Little is known about the extent and spatiotemporal profile of spinal rewiring, its regulation by neurotrophins or inflammatory cytokines, or its potential as a therapeutic target to improve stroke recovery. This commentary examines the recent findings by Sist et al. (2014) that there is a distinct critical period of heightened structural plasticity, growth factor expression, and inflammatory cytokine production in the spinal cord. They suggest that neuroplasticity is highest during the first two weeks after stroke and tapers off dramatically by the fourth week. Spinal cord plasticity correlates with the severity of cortical injury and temporally matches periods of accelerated spontaneous recovery of skilled reaching function. The potential of treatments that extend or re-open this window of spinal cord plasticity, such as anti-Nogo-A antibodies or chondroitinase ABC, to dramatically improve recovery from cortical stroke in clinical populations is discussed.
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Affiliation(s)
- Kelly A Tennant
- Division of Medical Sciences, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
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Present status and future challenges of electroencephalography- and magnetic resonance imaging-based monitoring in preclinical models of focal cerebral ischemia. Brain Res Bull 2014; 102:22-36. [PMID: 24462642 DOI: 10.1016/j.brainresbull.2014.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 01/07/2014] [Accepted: 01/14/2014] [Indexed: 12/16/2022]
Abstract
Animal models are useful tools for better understanding the mechanisms underlying neurological deterioration after an ischemic insult as well as subsequent evolution of changes and recovery of functions. In response to the updated requirements for preclinical investigations of stroke to include relevant functional measurement techniques and biomarker endpoints, we here review the state of knowledge on application of some translational electrophysiological and neuroimaging methods, and in particular, electroencephalography monitoring and magnetic resonance imaging in rodent models of ischemic stroke. This may lead to improvement of diagnostic methods and identification of new therapeutic targets, which would considerably advance the translational value of preclinical stroke research.
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Daadi MM, Hu S, Klausner J, Li Z, Sofilos M, Sun G, Wu JC, Steinberg GK. Imaging neural stem cell graft-induced structural repair in stroke. Cell Transplant 2013; 22:881-92. [PMID: 23044338 DOI: 10.3727/096368912x656144] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Stem cell therapy ameliorates motor deficits in experimental stroke model. Multimodal molecular imaging enables real-time longitudinal monitoring of infarct location, size, and transplant survival. In the present study, we used magnetic resonance imaging (MRI) and positron emission tomography (PET) to track the infarct evolution,tissue repair, and the fate of grafted cells. We genetically engineered embryonic stem cell-derived neural stem cells (NSCs) with a triple fusion reporter gene to express monomeric red fluorescence protein and herpes simplex virus-truncated thymidine kinase for multimodal molecular imaging and SPIO labeled for MRI. The infarct size as well as fate and function of grafted cells were tracked in real time for 3 months using MRI and PET. We report that grafted NSCs reduced the infarct size in animals with less than 0.1 cm(3) initial infarct in a dose-dependent manner, while larger stroke was not amenable to such beneficial effects. PET imaging revealed increased metabolic activity in grafted animals and visualized functioning grafted cells in vivo. Immunohistopathological analysis demonstrated that, after a 3-month survival period, grafted NSCs dispersed in the stroke-lesioned parenchyma and differentiated into neurons, astrocytes, and oligodendrocytes. Longitudinal multimodal imaging provides insights into time course dose-dependent interactions between NSC grafts and structural changes in infarcted tissue.
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Affiliation(s)
- Marcel M Daadi
- Department of Neurosurgery, Stanford Stroke Center and Stanford Institute for Neuro-Innovationand Translational Neurosciences, Stanford, CA, USA.
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Frostig RD, Lay CC, Davis MF. A rat's whiskers point the way toward a novel stimulus-dependent, protective stroke therapy. Neuroscientist 2013; 19:313-28. [PMID: 23047156 PMCID: PMC3710106 DOI: 10.1177/1073858412462607] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Stroke is the fourth leading cause of death in the United States and the leading cause of long-term disability. Ischemic stroke, due to an interruption in blood supply, is particularly prevalent; 87% of all strokes are ischemic. Unfortunately, current options for acute treatment are extremely limited and there is a great need for new treatment strategies. This review will discuss evidence that mild sensory stimulation can completely protect the jeopardized brain from an impending stroke in a rodent model. When delivered within the first 2 hours following ischemic onset, this stimulation results in complete protection, including a full reestablishment of cortical function, sensorimotor capabilities, and blood flow. Identical stimulation, however, initiated 3 hours following ischemic onset, results in an increase in damage compared with untreated animals. The protective effect is not specific to a single sensory modality, anesthesia, or age, and increasing evoked cortical activity by increasing stimulation accelerates recovery. Taken together, these findings demonstrate that cortical activity is a critical factor for protection and suggest a new, exciting potential avenue for the development of acute stroke treatment strategies that may produce a noninvasive, drug-free, equipment-free, and side effect-free means of protecting from ischemic stroke.
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Affiliation(s)
- Ron D Frostig
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA.
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Kalthoff D, Po C, Wiedermann D, Hoehn M. Reliability and spatial specificity of rat brain sensorimotor functional connectivity networks are superior under sedation compared with general anesthesia. NMR IN BIOMEDICINE 2013; 26:638-650. [PMID: 23303725 DOI: 10.1002/nbm.2908] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 11/12/2012] [Accepted: 11/21/2012] [Indexed: 06/01/2023]
Abstract
Functional connectivity networks derived from resting-state functional MRI (rsfMRI) have received increasing interest to further our understanding of brain function. The anesthesia in rodent models may influence the interpretation and comparison of results from functional connectivity MRI (fcMRI). More research is required on this aspect. In this study, we investigated rat brain connectivity networks under 1.5% isoflurane anesthesia in comparison with medetomidine sedation. rsfMRI data were acquired under both anesthesia conditions within one imaging session. Male Wistar rats (n = 17) were scanned at 11.7 T with focus on the sensorimotor system. The data underwent a per-subject independent component analysis (ICA), after which individual components were grouped using hierarchical clustering. Consistent and reliable networks were identified under medetomidine in sensorimotor cortex (three networks) and striatum (two networks). The incidence of these networks was drastically reduced under isoflurane. Seed correlation analysis confirmed these results and revealed globally elevated correlations with low topical specificity under isoflurane, stemming from low-frequency global signal fluctuations. Global signal removal thus enhanced slightly regional specificity under isoflurane and showed anti-correlations of cortico-striatal connections in both anesthesia regimes. Functional connectivity networks are thus reliably detected in medetomidine-sedated animals on an individual basis using ICA. Their occurrence, however, is heavily compromised under isoflurane as a result of global signal fluctuations potentially stemming from burst-suppression-like neural activity. Anesthesia and pharmacologically induced modulations may provide insight into network mechanisms in the future. As an agent for fcMRI in brain disease studies, light sedation using medetomidine preserves connectivity networks in a greater level of detail, and may therefore be considered superior to standard isoflurane anesthesia.
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Affiliation(s)
- Daniel Kalthoff
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
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Crum WR, Giampietro VP, Smith EJ, Gorenkova N, Stroemer RP, Modo M. A comparison of automated anatomical-behavioural mapping methods in a rodent model of stroke. J Neurosci Methods 2013; 218:170-83. [PMID: 23727124 PMCID: PMC3759848 DOI: 10.1016/j.jneumeth.2013.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 05/15/2013] [Accepted: 05/16/2013] [Indexed: 01/08/2023]
Abstract
The first application of voxel lesion symptom mapping (VLSM) in rodents. A comparison of VLSM with tensor based morphometry (TBM) methods in a stroke model. Comparison of automated techniques with manual measurements and model power calculations. Analysis of both local and non-local lesion effects. Correlation of structural change with behaviour.
Neurological damage, due to conditions such as stroke, results in a complex pattern of structural changes and significant behavioural dysfunctions; the automated analysis of magnetic resonance imaging (MRI) and discovery of structural–behavioural correlates associated with these disorders remains challenging. Voxel lesion symptom mapping (VLSM) has been used to associate behaviour with lesion location in MRI, but this analysis requires the definition of lesion masks on each subject and does not exploit the rich structural information in the images. Tensor-based morphometry (TBM) has been used to perform voxel-wise structural analyses over the entire brain; however, a combination of lesion hyper-intensities and subtle structural remodelling away from the lesion might confound the interpretation of TBM. In this study, we compared and contrasted these techniques in a rodent model of stroke (n = 58) to assess the efficacy of these techniques in a challenging pre-clinical application. The results from the automated techniques were compared using manually derived region-of-interest measures of the lesion, cortex, striatum, ventricle and hippocampus, and considered against model power calculations. The automated TBM techniques successfully detect both lesion and non-lesion effects, consistent with manual measurements. These techniques do not require manual segmentation to the same extent as VLSM and should be considered part of the toolkit for the unbiased analysis of pre-clinical imaging-based studies.
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Affiliation(s)
- William R Crum
- King's College London, Institute of Psychiatry, Department of Neuroimaging, London SE5 8AF, UK.
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Brain connectivity plasticity in the motor network after ischemic stroke. Neural Plast 2013; 2013:924192. [PMID: 23738150 PMCID: PMC3655657 DOI: 10.1155/2013/924192] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Accepted: 04/07/2013] [Indexed: 01/06/2023] Open
Abstract
The motor function is controlled by the motor system that comprises a series of cortical and subcortical areas interacting via anatomical connections. The motor function will be disturbed when the stroke lesion impairs either any of these areas or their connections. More and more evidence indicates that the reorganization of the motor network including both areas and their anatomical and functional connectivity might contribute to the motor recovery after stroke. Here, we review recent studies employing models of anatomical, functional, and effective connectivity on neuroimaging data to investigate how ischemic stroke influences the connectivity of motor areas and how changes in connectivity relate to impaired function and functional recovery. We suggest that connectivity changes constitute an important pathophysiological aspect of motor impairment after stroke and important mechanisms of motor recovery. We also demonstrate that therapeutic interventions may facilitate motor recovery after stroke by modulating the connectivity among the motor areas. In conclusion, connectivity analyses improved our understanding of the mechanisms of motor recovery after stroke and may help to design hypothesis-driven treatment strategies and sensitive measures for outcome prediction in stroke patients.
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47
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Salinet ASM, Haunton VJ, Panerai RB, Robinson TG. A systematic review of cerebral hemodynamic responses to neural activation following stroke. J Neurol 2013; 260:2715-21. [DOI: 10.1007/s00415-013-6836-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 01/04/2013] [Indexed: 10/27/2022]
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Fukuda M, Vazquez AL, Zong X, Kim SG. Effects of the α₂-adrenergic receptor agonist dexmedetomidine on neural, vascular and BOLD fMRI responses in the somatosensory cortex. Eur J Neurosci 2012; 37:80-95. [PMID: 23106361 DOI: 10.1111/ejn.12024] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Accepted: 09/19/2012] [Indexed: 01/20/2023]
Abstract
This article describes the effects of dexmedetomidine (DEX) - the active ingredient of medetomidine, which is the latest popular sedative for functional magnetic resonance imaging (fMRI) in rodents - on multiple unit activity, local field potential (LFP), cerebral blood flow (CBF), pial vessel diameter [indicative of cerebral blood volume (CBV)], and blood oxygenation level-dependent (BOLD) fMRI. These measurements were obtained from the rat somatosensory cortex during 10 s of forepaw stimulation. We found that the continuous intravascular systemic infusion of DEX (50 μg/kg/h, doses typically used in fMRI studies) caused epileptic activities, and that supplemental isoflurane (ISO) administration of ~0.3% helped to suppress the development of epileptic activities and maintained robust neuronal and hemodynamic responses for up to 3 h. Supplemental administration of N(2)O in addition to DEX nearly abolished hemodynamic responses even if neuronal activity remained. Under DEX + ISO anesthesia, spike firing rate and the delta power of LFP increased, whereas beta and gamma power decreased, as compared with ISO-only anesthesia. DEX administration caused pial arteries and veins to constrict nearly equally, resulting in decreases in baseline CBF and CBV. Evoked LFP and CBF responses to forepaw stimulation were largest at a frequency of 8-10 Hz, and a non-linear relationship was observed. Similarly, BOLD fMRI responses measured at 9.4 T were largest at a frequency of 10 Hz. Both pial arteries and veins dilated rapidly (artery, 32.2%; vein, 5.8%), and venous diameter returned to baseline slower than arterial diameter. These results will be useful for designing, conducting and interpreting fMRI experiments under DEX sedation.
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Affiliation(s)
- Mitsuhiro Fukuda
- Neuroimaging Laboratory, Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA.
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Po C, Kalthoff D, Kim YB, Nelles M, Hoehn M. White matter reorganization and functional response after focal cerebral ischemia in the rat. PLoS One 2012; 7:e45629. [PMID: 23029148 PMCID: PMC3445514 DOI: 10.1371/journal.pone.0045629] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Accepted: 08/20/2012] [Indexed: 11/18/2022] Open
Abstract
After stroke, the brain has shown to be able to achieve spontaneous functional recovery despite severe cerebral damage. This phenomenon is poorly understood. To address this issue, focal transient ischemia was induced by 60 min middle cerebral artery occlusion in Wistar rats. The evolution of stroke was followed using two magnetic resonance imaging modalities: diffusion spectrum imaging (acquired before, one and four weeks after stroke) and functional magnetic resonance imaging (acquired before and five weeks after stroke). To confirm the imaging observations, immunohistochemical staining for myelin, astrocytes and macrophages/microglia was added. At four weeks after stroke, a focal alteration of the diffusion anisotropy was observed between the ipsilesional ventricle and the lesion area. Using tractography this perturbation was identified as reorganization of the ipsilesional internal capsule. Functional imaging at five weeks after ischemia demonstrated activation of the primary sensorimotor cortex in both hemispheres in all rats except one animal lacking a functional response in the ipsilesional cortex. Furthermore, fiber tracking showed a transhemispheric fiber connection through the corpus callosum, which-in the rat without functional recovery-was lost. Our study shows the influence of the internal capsule reorganization, combined with inter-hemispheric connections though the corpus callosum, on the functional activation of the brain from stroke. In conclusion, tractography opens a new door to non-invasively investigate the structural correlates of lack of functional recovery after stroke.
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Affiliation(s)
- Chrystelle Po
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
| | - Daniel Kalthoff
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
| | - Young Beom Kim
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
| | - Melanie Nelles
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
| | - Mathias Hoehn
- In-vivo-NMR Laboratory, Max Planck Institute for Neurological Research, Cologne, Germany
- * E-mail:
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Arnberg F, Lundberg J, Söderman M, Damberg P, Holmin S. Image-Guided Method in the Rat for Inducing Cortical or Striatal Infarction and for Controlling Cerebral Blood Flow Under MRI. Stroke 2012; 43:2437-43. [DOI: 10.1161/strokeaha.112.655126] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Fabian Arnberg
- From the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden (F.A., J.L., M.S., S.H.); and the Departments of Neuroradiology (F.A., J.L., M.S., S.H.), Radiology (F.A.), and Neurobiology Care Science and Society (P.D.), Karolinska University Hospital, Stockholm, Sweden
| | - Johan Lundberg
- From the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden (F.A., J.L., M.S., S.H.); and the Departments of Neuroradiology (F.A., J.L., M.S., S.H.), Radiology (F.A.), and Neurobiology Care Science and Society (P.D.), Karolinska University Hospital, Stockholm, Sweden
| | - Michael Söderman
- From the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden (F.A., J.L., M.S., S.H.); and the Departments of Neuroradiology (F.A., J.L., M.S., S.H.), Radiology (F.A.), and Neurobiology Care Science and Society (P.D.), Karolinska University Hospital, Stockholm, Sweden
| | - Peter Damberg
- From the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden (F.A., J.L., M.S., S.H.); and the Departments of Neuroradiology (F.A., J.L., M.S., S.H.), Radiology (F.A.), and Neurobiology Care Science and Society (P.D.), Karolinska University Hospital, Stockholm, Sweden
| | - Staffan Holmin
- From the Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden (F.A., J.L., M.S., S.H.); and the Departments of Neuroradiology (F.A., J.L., M.S., S.H.), Radiology (F.A.), and Neurobiology Care Science and Society (P.D.), Karolinska University Hospital, Stockholm, Sweden
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