scholarly journals Brain Connectivity Plasticity in the Motor Network after Ischemic Stroke

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Lin Jiang ◽  
Huijuan Xu ◽  
Chunshui Yu
Keyword(s):  
Ischemic Stroke ◽  
Motor Function ◽  
Brain Connectivity ◽  
Effective Connectivity ◽  
Motor Impairment ◽  
Treatment Strategies ◽  
Motor Recovery ◽  
Therapeutic Interventions ◽  
Motor Network ◽  
Motor Areas

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.

Abstract TP75: Normal Appearing White Matter Integrity and Motor Impairment Severity in Acute Ischemic Stroke

Stroke ◽  
2020 ◽  
Vol 51 (Suppl_1) ◽  
Author(s):  
Carson Ingo ◽  
Chen Lin ◽  
James Higgins ◽  
Yurany Arevalo ◽  
Shyam Prabhakaran
Keyword(s):  
Ischemic Stroke ◽  
White Matter ◽  
Acute Ischemic Stroke ◽  
Motor Function ◽  
Motor Impairment ◽  
Internal Capsule ◽  
Posterior Limb ◽  
Normal Appearing White Matter ◽  
Stroke Group ◽  
Microstructural Integrity

Introduction: The effect of white matter hyperintensities (WMH) as measured by fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging on functional impairment and recovery after ischemic stroke has been investigated thoroughly. However, there has been growing interest to investigate normal-appearing white matter (NAWM) microstructural integrity following ischemic stroke onset with techniques such as diffusion tensor imaging (DTI). Methods: 52 patients with acute ischemic stroke and 36 without stroke were evaluated with a DTI and FLAIR imaging protocol and clinically assessed for severity of motor impairment using the Motricity Index within 72 hours of suspected symptom onset. Results: There were widespread decreases in fractional anisotropy (FA) and increases in mean diffusivity (MD) and radial diffusivity (RD) for the acute stroke group compared to the non-stroke group. As shown in the abstract figure with the blue voxels, there was a significant positive association between FA and motor function and a significant negative association between MD/RD and motor function. The NAWM regions of interest that were most sensitive to the Motricity Index were the anterior/posterior limb of the internal capsule in the infarcted hemisphere and the splenium of the corpus callosum, external capsule, posterior limb/retrolenticular part of the internal capsule, superior longitudinal fasciculus, and cingulum (hippocampus) of the intra-/contralateral hemisphere. Conclusion: The microstructural integrity of NAWM is a significant parameter to identify neural differences not only between those individuals with and without acute ischemic stroke, but also correlated with severity of acute motor impairment.

scholarly journals Dynamics of brain connectivity after stroke

2019 ◽  
Vol 30 (6) ◽  
pp. 605-623 ◽  
Author(s):  
Adela Desowska ◽  
Duncan L. Turner
Keyword(s):  
Brain Connectivity ◽  
Effective Connectivity ◽  
Network Connectivity ◽  
Connectivity Pattern ◽  
Compensatory Mechanisms ◽  
Neural Structure ◽  
Motor Network ◽  
The Central Nervous System ◽  
Dynamic Time ◽  
The Impact

Abstract Recovery from a stroke is a dynamic time-dependent process, in which the central nervous system reorganises to accommodate for the impact of the injury. The purpose of this paper is to review recent longitudinal studies of changes in brain connectivity after stroke. A systematic review of research papers reporting functional or effective connectivity at two or more time points in stroke patients was conducted. Stroke leads to an early reduction of connectivity in the motor network. With recovery time, the connectivity increases and can reach the same levels as in healthy participants. The increase in connectivity is correlated with functional motor gains. A new, more randomised pattern of connectivity may then emerge in the longer term. In some instances, a pattern of increased connectivity even higher than in healthy controls can be observed, and is related either to a specific time point or to a specific neural structure. Rehabilitation interventions can help improve connectivity between specific regions. Moreover, motor network connectivity undergoes reorganisation during recovery from a stroke and can be related to behavioural recovery. A detailed analysis of changes in connectivity pattern may enable a better understanding of adaptation to a stroke and how compensatory mechanisms in the brain may be supported by rehabilitation.

scholarly journals Patterns of motor recovery and structural neuroplasticity after basal ganglia infarcts

Neurology ◽  
2020 ◽  
Vol 95 (9) ◽  
pp. e1174-e1187
Author(s):  
Hesheng Liu ◽  
Xiaolong Peng ◽  
Louisa Dahmani ◽  
Hongfeng Wang ◽  
Miao Zhang ◽  
...  
Keyword(s):  
Basal Ganglia ◽  
Cortical Thickness ◽  
A Priori ◽  
Treatment Strategies ◽  
Motor Recovery ◽  
Cortical Reorganization ◽  
Resting State Functional Connectivity ◽  
Motor Network ◽  
Healthy Control ◽  
Cerebral Reorganization

ObjectiveTo elucidate the timeframe and spatial patterns of cortical reorganization after different stroke-induced basal ganglia lesions, we measured cortical thickness at 5 time points over a 6-month period. We hypothesized that cortical reorganization would occur very early and that, along with motor recovery, it would vary based on the stroke lesion site.MethodsThirty-three patients with unilateral basal ganglia stroke and 23 healthy control participants underwent MRI scanning and behavioral testing. To further decrease heterogeneity, we split patients into 2 groups according to whether or not the lesions mainly affect the striatal motor network as defined by resting-state functional connectivity. A priori measures included cortical thickness and motor outcome, as assessed with the Fugl-Meyer scale.ResultsWithin 14 days poststroke, cortical thickness already increased in widespread brain areas (p = 0.001), mostly in the frontal and temporal cortices rather than in the motor cortex. Critically, the 2 groups differed in the severity of motor symptoms (p = 0.03) as well as in the cerebral reorganization they exhibited over a period of 6 months (Dice overlap index = 0.16). Specifically, the frontal and temporal regions demonstrating cortical thickening showed minimal overlap between these 2 groups, indicating different patterns of reorganization.ConclusionsOur findings underline the importance of assessing patients early and of considering individual differences, as patterns of cortical reorganization differ substantially depending on the precise location of damage and occur very soon after stroke. A better understanding of the macrostructural brain changes following stroke and their relationship with recovery may inform individualized treatment strategies.

scholarly journals Optogenetic Stimulation Enhanced Neuronal Plasticities in Motor Recovery after Ischemic Stroke

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Changbo Lu ◽  
Xianglong Wu ◽  
Hongzhe Ma ◽  
Qingchuan Wang ◽  
Yikai Wang ◽  
...  
Keyword(s):  
Nervous System ◽  
Ischemic Stroke ◽  
Animal Models ◽  
Motor Function ◽  
Neural Circuits ◽  
Motor Recovery ◽  
Motor Functions ◽  
Optogenetic Stimulation ◽  
Function Recovery ◽  
Structural Connection

Motor capability recovery after ischemic stroke involves dynamic remodeling processes of neural connectomes in the nervous system. Various neuromodulatory strategies combining direct stimulating interventions with behavioral trainings for motor recovery after ischemic stroke have been developed. However, the effectiveness of these interventions varies widely due to unspecific activation or inhibition of undefined neuronal subtypes. Optogenetics is a functional and structural connection-based approach that can selectively activate or inhibit specific subtype neurons with a higher precision, and it has been widely applied to build up neuronal plasticities of the nervous system, which shows a great potential in restoring motor functions in stroke animal models. Here, we reviewed neurobiological mechanisms of enhanced brain plasticities underlying motor recovery through the optogenetic stimulation after ischemic stroke. Several brain sites and neural circuits that have been previously proven effective for motor function rehabilitation were identified, which would be helpful for a more schematic understanding of effective neuronal connectomes in the motor function recovery after ischemic stroke.

scholarly journals Cerebrolysin Combined with Rehabilitation Enhances Motor Recovery and Prevents Neural Network Degeneration in Ischemic Stroke Patients with Severe Motor Deficits

2021 ◽  
Vol 11 (6) ◽  
pp. 545
Author(s):  
Won Hyuk Chang ◽  
Jungsoo Lee ◽  
Yong-Il Shin ◽  
Myoung-Hwan Ko ◽  
Deog Young Kim ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Diffusion Tensor ◽  
Motor Impairment ◽  
Motor Recovery ◽  
Stroke Onset ◽  
Stroke Patients ◽  
Rehabilitation Therapy ◽  
Severe Motor ◽  
Severe Motor Impairment ◽  
Over Time

The objective of this study was to evaluate whether Cerebrolysin combined with rehabilitation therapy supports additional motor recovery in stroke patients with severe motor impairment. This study analyzed the combined data from the two phase IV prospective, multicenter, randomized, double-blind, placebo-controlled trials. Stroke patients were included within seven days after stroke onset and were randomized to receive a 21-day treatment course of either Cerebrolysin or placebo with standardized rehabilitation therapy. Assessments were performed at baseline, immediately after the treatment course, and 90 days after stroke onset. The plasticity of the motor system was assessed by diffusion tensor imaging and resting state fMRI. In total, 110 stroke patients were included for the full analysis set (Cerebrolysin n = 59, placebo n = 51). Both groups showed significant motor recovery over time. Repeated-measures analysis of varianceshowed a significant interaction between time and type of intervention as measured by the Fugl–Meyer Assessment (p < 0.05). The Cerebrolysin group demonstrated less degenerative changes in the major motor-related white matter tracts over time than the placebo group. In conclusion, Cerebrolysin treatment as an add-on to a rehabilitation program is a promising pharmacologic approach that is worth considering in order to enhance motor recovery in ischemic stroke patients with severe motor impairment.

scholarly journals TMS-Induced Central Motor Conduction Time at the Non-Infarcted Hemisphere is Associated with Spontaneous Motor Recovery of the Paretic Upper Limb after Severe Stroke

2021 ◽  
Vol 11 (5) ◽  
pp. 648
Author(s):  
Maurits Hoonhorst ◽  
Rinske Nijland ◽  
Cornelis Emmelot ◽  
Boudewijn Kollen ◽  
Gert Kwakkel
Keyword(s):  
Ischemic Stroke ◽  
Upper Limb ◽  
Normative Data ◽  
Motor Impairment ◽  
Motor Recovery ◽  
Conduction Time ◽  
Stroke Patients ◽  
Severe Stroke ◽  
Central Motor Conduction Time ◽  
Post Stroke

Background: Stroke affects the neuronal networks of the non-infarcted hemisphere. The central motor conduction time (CMCT) induced by transcranial magnetic stimulation (TMS) could be used to determine the conduction time of the corticospinal tract of the non-infarcted hemisphere after a stroke. Objectives: Our primary aim was to demonstrate the existence of prolonged CMCT in the non-infarcted hemisphere, measured within the first 48 h when compared to normative data, and secondly, if the severity of motor impairment of the affected upper limb was significantly associated with prolonged CMCTs in the non-infarcted hemisphere when measured within the first 2 weeks post stroke. Methods: CMCT in the non-infarcted hemisphere was measured in 50 patients within 48 h and at 11 days after a first-ever ischemic stroke. Patients lacking significant spontaneous motor recovery, so-called non-recoverers, were defined as those who started below 18 points on the FM-UE and showed less than 6 points (10%) improvement within 6 months. Results: CMCT in the non-infarcted hemisphere was prolonged in 30/50 (60%) patients within 48 h and still in 24/49 (49%) patients at 11 days. Sustained prolonged CMCT in the non-infarcted hemisphere was significantly more frequent in non-recoverers following FM-UE. Conclusions: The current study suggests that CMCT in the non-infarcted hemisphere is significantly prolonged in 60% of severely affected, ischemic stroke patients when measured within the first 48 h post stroke. The likelihood of CMCT is significantly higher in non-recoverers when compared to those that show spontaneous motor recovery early post stroke.

scholarly journals Conditional Granger Causality Analysis of Effective Connectivity during Motor Imagery and Motor Execution in Stroke Patients

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Li Wang ◽  
Jingna Zhang ◽  
Ye Zhang ◽  
Rubing Yan ◽  
Hongliang Liu ◽  
...  
Keyword(s):  
Granger Causality ◽  
Motor Function ◽  
Motor Imagery ◽  
Effective Connectivity ◽  
Causality Analysis ◽  
Motor Execution ◽  
Stroke Patients ◽  
Granger Causality Analysis ◽  
Cortical Motor ◽  
Motor Network

Aims.Motor imagery has emerged as a promising technique for the improvement of motor function following stroke, but the mechanism of functional network reorganization in patients during this process remains unclear. The aim of this study is to evaluate the cortical motor network patterns of effective connectivity in stroke patients.Methods.Ten stroke patients with right hand hemiplegia and ten normal control subjects were recruited. We applied conditional Granger causality analysis (CGCA) to explore and compare the functional connectivity between motor execution and motor imagery.Results.Compared with the normal controls, the patient group showed lower effective connectivity to the primary motor cortex (M1), the premotor cortex (PMC), and the supplementary motor area (SMA) in the damaged hemisphere but stronger effective connectivity to the ipsilesional PMC and M1 in the intact hemisphere during motor execution. There were tighter connections in the cortical motor network in the patients than in the controls during motor imagery, and the patients showed more effective connectivity in the intact hemisphere.Conclusions.The increase in effective connectivity suggests that motor imagery enhances core corticocortical interactions, promotes internal interaction in damaged hemispheres in stroke patients, and may facilitate recovery of motor function.

scholarly journals Motor Recovery of the Affected Hand in Subacute Stroke Correlates with Changes of Contralesional Cortical Hand Motor Representation

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Jitka Veldema ◽  
Kathrin Bösl ◽  
Dennis Alexander Nowak
Keyword(s):  
Motor Function ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Motor Evoked Potentials ◽  
Wide Spectrum ◽  
Motor Impairment ◽  
Motor Recovery ◽  
Motor Representation ◽  
Subacute Stroke ◽  
Resting Motor Threshold

Objective. To investigate the relationship between changes of cortical hand motor representation and motor recovery of the affected hand in subacute stroke. Methods. 17 patients with motor impairment of the affected hand were enrolled in an in-patient neurological rehabilitation program. Hand motor function tests (Wolf Motor Function Test, Action Research Arm Test) and neurophysiological evaluations (resting motor threshold, motor evoked potentials, motor map area size, motor map area volume, and motor map area location) were obtained from both hands and hemispheres at baseline and two, four, and six weeks of in-patient rehabilitation. Results. There was a wide spectrum of hand motor impairment at baseline and hand motor recovery over time. Hand motor function and recovery correlated significantly with (i) reduction of cortical excitability, (ii) reduction in size and volume of cortical hand motor representation, and (iii) a medial and anterior shift of the center of gravity of cortical hand motor representation within the contralesional hemisphere. Conclusion. Recovery of motor function of the affected hand after stroke is accompanied by definite changes in excitability, size, volume, and location of hand motor representation over the contralesional primary motor cortex. These measures may serve as surrogate markers for the outcome of hand motor rehabilitation after stroke.

Motor Recovery after Chronic Spinal Cord Transection in Rats: A Proof-of-Concept Study Evaluating a Combined Strategy

2019 ◽  
Vol 18 (1) ◽  
pp. 52-62 ◽  
Author(s):  
Antonio Ibarra ◽  
Erika Mendieta-Arbesú ◽  
Paola Suarez-Meade ◽  
Elisa García-Vences ◽  
Susana Martiñón ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Treatment Strategies ◽  
Chronic Phase ◽  
Motor Recovery ◽  
Neural Regeneration ◽  
Histological Evaluation ◽  
Control Group ◽  
Proof Of Concept ◽  
Sprague Dawley ◽  
Concept Study

Background: The chronic phase of Spinal Cord (SC) injury is characterized by the presence of a hostile microenvironment that causes low activity and a progressive decline in neurological function; this phase is non-compatible with regeneration. Several treatment strategies have been investigated in chronic SC injury with no satisfactory results. OBJECTIVE- In this proof-of-concept study, we designed a combination therapy (Comb Tx) consisting of surgical glial scar removal plus scar inhibition, accompanied with implantation of mesenchymal stem cells (MSC), and immunization with neural-derived peptides (INDP). Methods: This study was divided into three subsets, all in which Sprague Dawley rats were subjected to a complete SC transection. Sixty days after injury, animals were randomly allocated into two groups for therapeutic intervention: control group and animals receiving the Comb-Tx. Sixty-three days after treatment we carried out experiments analyzing motor recovery, presence of somatosensory evoked potentials, neural regeneration-related genes, and histological evaluation of serotoninergic fibers. Results: Comb-Tx induced a significant locomotor and electrophysiological recovery. An increase in the expression of regeneration-associated genes and the percentage of 5-HT+ fibers was noted at the caudal stump of the SC of animals receiving the Comb-Tx. There was a significant correlation of locomotor recovery with positive electrophysiological activity, expression of GAP43, and percentage of 5-HT+ fibers. Conclusion: Comb-Tx promotes motor and electrophysiological recovery in the chronic phase of SC injury subsequent to a complete transection. Likewise, it is capable of inducing the permissive microenvironment to promote axonal regeneration.

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