scholarly journals Role of Interhemispheric Cortical Interactions in Poststroke Motor Function

2019 ◽  
Vol 33 (9) ◽  
pp. 762-774 ◽  
Author(s):  
Jacqueline A. Palmer ◽  
Lewis A. Wheaton ◽  
Whitney A. Gray ◽  
Mary Alice Saltão da Silva ◽  
Steven L. Wolf ◽  
...  
Keyword(s):  
Motor Function ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Negatively Associated ◽  
Interhemispheric Coherence ◽  
Stroke Group ◽  
Active Condition ◽  
Hand Muscle ◽  
Clinical Measures

Background/Objective. We investigated interhemispheric interactions in stroke survivors by measuring transcranial magnetic stimulation (TMS)–evoked cortical coherence. We tested the effect of TMS on interhemispheric coherence during rest and active muscle contraction and compared coherence in stroke and older adults. We evaluated the relationships between interhemispheric coherence, paretic motor function, and the ipsilateral cortical silent period (iSP). Methods. Participants with (n = 19) and without (n = 14) chronic stroke either rested or maintained a contraction of the ipsilateral hand muscle during simultaneous recordings of evoked responses to TMS of the ipsilesional/nondominant (i/ndM1) and contralesional/dominant (c/dM1) primary motor cortex with EEG and in the hand muscle with EMG. We calculated pre- and post-TMS interhemispheric beta coherence (15-30 Hz) between motor areas in both conditions and the iSP duration during the active condition. Results. During active i/ndM1 TMS, interhemispheric coherence increased immediately following TMS in controls but not in stroke. Coherence during active cM1 TMS was greater than iM1 TMS in the stroke group. Coherence during active iM1 TMS was less in stroke participants and was negatively associated with measures of paretic arm motor function. Paretic iSP was longer compared with controls and negatively associated with clinical measures of manual dexterity. There was no relationship between coherence and. iSP for either group. No within- or between-group differences in coherence were observed at rest. Conclusions. TMS-evoked cortical coherence during hand muscle activation can index interhemispheric interactions associated with poststroke motor function and potentially offer new insights into neural mechanisms influencing functional recovery.

scholarly journals Reduced Interhemispheric Coherence in Cerebellar Kainic Acid-Induced Lateralized Dystonia

2020 ◽  
Vol 11 ◽  
Author(s):  
Elena Laura Georgescu Margarint ◽  
Ioana Antoaneta Georgescu ◽  
Carmen Denise Mihaela Zahiu ◽  
Stefan-Alexandru Tirlea ◽  
Alexandru Rǎzvan Şteopoaie ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Kainic Acid ◽  
Primary Motor Cortex ◽  
Low Frequency ◽  
Muscular Activity ◽  
Cerebellar Hemisphere ◽  
Interhemispheric Coherence ◽  
General Locomotor Activity ◽  
Complex Circuits ◽  
The Right

The execution of voluntary muscular activity is controlled by the primary motor cortex, together with the cerebellum and basal ganglia. The synchronization of neural activity in the intracortical network is crucial for the regulation of movements. In certain motor diseases, such as dystonia, this synchrony can be altered in any node of the cerebello-cortical network. Questions remain about how the cerebellum influences the motor cortex and interhemispheric communication. This research aims to study the interhemispheric cortical communication between the motor cortices during dystonia, a neurological movement syndrome consisting of sustained or repetitive involuntary muscle contractions. We pharmacologically induced lateralized dystonia to adult male albino mice by administering low doses of kainic acid on the left cerebellar hemisphere. Using electrocorticography and electromyography, we investigated the power spectral densities, cortico-muscular, and interhemispheric coherence between the right and left motor cortices, before and during dystonia, for five consecutive days. Mice displayed lateralized abnormal motor signs, a reduced general locomotor activity, and a high score of dystonia. The results showed a progressive interhemispheric coherence decrease in low-frequency bands (delta, theta, beta) during the first 3 days. The cortico-muscular coherence of the affected side had a significant increase in gamma bands on days 3 and 4. In conclusion, lateralized cerebellar dysfunction during dystonia was associated with a loss of connectivity in the motor cortices, suggesting a possible cortical compensation to the initial disturbances induced by cerebellar left hemisphere kainate activation by blocking the propagation of abnormal oscillations to the healthy hemisphere. However, the cerebellum is part of several overly complex circuits, therefore other mechanisms can still be involved in this phenomenon.

scholarly journals Cortical silent period reflects individual differences in action stopping performance

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mario Paci ◽  
Giulio Di Cosmo ◽  
Mauro Gianni Perrucci ◽  
Francesca Ferri ◽  
Marcello Costantini
Keyword(s):  
Individual Differences ◽  
Response Inhibition ◽  
Primary Motor Cortex ◽  
Silent Period ◽  
Intracortical Inhibition ◽  
Stop Signal ◽  
Stop Signal Task ◽  
Behavioral Differences ◽  
Cortical Silent Period ◽  
Stop Signal Reaction Time

AbstractInhibitory control is the ability to suppress inappropriate movements and unwanted actions, allowing to regulate impulses and responses. This ability can be measured via the Stop Signal Task, which provides a temporal index of response inhibition, namely the stop signal reaction time (SSRT). At the neural level, Transcranial Magnetic Stimulation (TMS) allows to investigate motor inhibition within the primary motor cortex (M1), such as the cortical silent period (CSP) which is an index of GABAB-mediated intracortical inhibition within M1. Although there is strong evidence that intracortical inhibition varies during action stopping, it is still not clear whether differences in the neurophysiological markers of intracortical inhibition contribute to behavioral differences in actual inhibitory capacities. Hence, here we explored the relationship between intracortical inhibition within M1 and behavioral response inhibition. GABABergic-mediated inhibition in M1 was determined by the duration of CSP, while behavioral inhibition was assessed by the SSRT. We found a significant positive correlation between CSP’s duration and SSRT, namely that individuals with greater levels of GABABergic-mediated inhibition seem to perform overall worse in inhibiting behavioral responses. These results support the assumption that individual differences in intracortical inhibition are mirrored by individual differences in action stopping abilities.

scholarly journals The Role of Continuous Theta Burst TMS in the Neurorehabilitation of Subacute Stroke Patients: A Placebo-Controlled Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Ana Dionísio ◽  
Rita Gouveia ◽  
João Castelhano ◽  
Isabel Catarina Duarte ◽  
Gustavo C. Santo ◽  
...  
Keyword(s):  
Motor Function ◽  
Primary Motor Cortex ◽  
Phase Iii ◽  
Repeated Measure ◽  
Controlled Study ◽  
Stroke Patients ◽  
Post Stroke ◽  
Subacute Stroke ◽  
Theta Burst

Objectives: Transcranial magnetic stimulation, in particular continuous theta burst (cTBS), has been proposed for stroke rehabilitation, based on the concept that inhibition of the healthy hemisphere helps promote the recovery of the lesioned one. We aimed to study its effects on cortical excitability, oscillatory patterns, and motor function, the main aim being to identify potentially beneficial neurophysiological effects.Materials and Methods: We applied randomized real or placebo stimulation over the unaffected primary motor cortex of 10 subacute (7 ± 3 days) post-stroke patients. Neurophysiological measurements were performed using electroencephalography and electromyography. Motor function was assessed with the Wolf Motor Function Test. We performed a repeated measure study with the recordings taken pre-, post-cTBS, and at 3 months' follow-up.Results: We investigated changes in motor rhythms during arm elevation and thumb opposition tasks and found significant changes in beta power of the affected thumb's opposition, specifically after real cTBS. Our results are consistent with an excitatory response (increase in event-related desynchronization) in the sensorimotor cortical areas of the affected hemisphere, after stimulation. Neither peak-to-peak amplitude of motor-evoked potentials nor motor performance were significantly altered.Conclusions: Consistently with the theoretical prediction, this contralateral inhibitory stimulation paradigm changes neurophysiology, leading to a significant excitatory impact on the cortical oscillatory patterns of the contralateral hemisphere. These proof-of-concept results provide evidence for the potential role of continuous TBS in the neurorehabilitation of post-stroke patients. We suggest that these changes in ERS/ERD patterns should be further explored in future phase IIb/phase III clinical trials, in larger samples of poststroke 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.

Cathodal transcranial direct current stimulation of the primary motor cortex improves selective muscle activation in the ipsilateral arm

2011 ◽  
Vol 105 (6) ◽  
pp. 2937-2942 ◽  
Author(s):  
Alana B. McCambridge ◽  
Lynley V. Bradnam ◽  
Cathy M. Stinear ◽  
Winston D. Byblow
Keyword(s):  
Motor Cortex ◽  
Upper Limb ◽  
Direct Current ◽  
Transcranial Direct Current Stimulation ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Selectivity Ratio ◽  
Direct Current Stimulation ◽  
Antagonist Muscles ◽  
Stimulation Of

Proximal upper limb muscles are represented bilaterally in primary motor cortex. Goal-directed upper limb movement requires precise control of proximal and distal agonist and antagonist muscles. Failure to suppress antagonist muscles can lead to abnormal movement patterns, such as those commonly experienced in the proximal upper limb after stroke. We examined whether noninvasive brain stimulation of primary motor cortex could be used to improve selective control of the ipsilateral proximal upper limb. Thirteen healthy participants performed isometric left elbow flexion by contracting biceps brachii (BB; agonist) and left forearm pronation (BB antagonist) before and after 20 min of cathodal transcranial direct current stimulation (c-tDCS) or sham tDCS of left M1. During the tasks, motor evoked potentials (MEPs) in left BB were acquired using single-pulse transcranial magnetic stimulation of right M1 150–270 ms before muscle contraction. As expected, left BB MEPs were facilitated before flexion and suppressed before pronation. After c-tDCS, left BB MEP amplitudes were reduced compared with sham stimulation, before pronation but not flexion, indicating that c-tDCS enhanced selective muscle activation of the ipsilateral BB in a task-specific manner. The potential for c-tDCS to improve BB antagonist control correlated with BB MEP amplitude for pronation relative to flexion, expressed as a selectivity ratio. This is the first demonstration that selective muscle activation in the proximal upper limb can be improved after c-tDCS of ipsilateral M1 and that the benefits of c-tDCS for selective muscle activation may be most effective in cases where activation strategies are already suboptimal. These findings may have relevance for the use of tDCS in rehabilitation after stroke.

Transcranial magnetic stimulation

2016 ◽  
Author(s):  
Kerry R. Mills
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Neurons ◽  
Magnetic Stimulation ◽  
Motor Evoked Potential ◽  
Silent Period ◽  
Demyelinating Diseases ◽  
Conduction Time ◽  
Spinal Motor Neurons ◽  
Basic Physics ◽  
Clinical Measures

Transcranial magnetic stimulation (TMS) has been exploited to advance knowledge of corticospinal physiology and, in a number of conditions, to aid diagnosis and quantify corticospinal abnormalities. The basic physics of magnetic stimulation is described along with the effects of stimulating coils with different dimensions and shape. The effects of single TMS pulses over motor cortex to cause a descending volley of D and I waves, and their effects on spinal motor neurons resulting in a motor evoked potential (MEP) are described. Guidelines for the safe use of TMS are given. Methods to estimate useful clinical measures of corticospinal function, such as threshold, MEP amplitude, central motor conduction time, silent period and input:output relation are given, as is the means to quantify corticospinal conduction using the triple stimulation technique. The clinical utility of TMS in neurodegenerations, central demyelinating diseases, stroke, spinal cord disease, movement disorders, and functional disorders is discussed.

scholarly journals Low-Frequency Oscillations Are a Biomarker of Injury and Recovery After Stroke

Stroke ◽  
2020 ◽  
Vol 51 (5) ◽  
pp. 1442-1450 ◽  
Author(s):  
Jessica M. Cassidy ◽  
Anirudh Wodeyar ◽  
Jennifer Wu ◽  
Kiranjot Kaur ◽  
Ashley K. Masuda ◽  
...  
Keyword(s):  
Primary Motor Cortex ◽  
Low Frequency ◽  
Inpatient Rehabilitation ◽  
Motor Recovery ◽  
Rehabilitation Facility ◽  
Low Frequency Oscillations ◽  
Band Power ◽  
Interhemispheric Coherence ◽  
Delta Band ◽  
Inpatient Rehabilitation Facility

Background and Purpose— Low-frequency oscillations reflect brain injury but also contribute to normal behaviors. We examined hypotheses relating electroencephalography measures, including low-frequency oscillations, to injury and motor recovery poststroke. Methods— Patients with stroke completed structural neuroimaging, a resting-state electroencephalography recording and clinical testing. A subset admitted to an inpatient rehabilitation facility also underwent serial electroencephalography recordings. The relationship that electroencephalography measures (power and coherence with leads overlying ipsilesional primary motor cortex [iM1]) had with injury and motor status was assessed, focusing on delta (1–3 Hz) and high-beta (20–30 Hz) bands. Results— Across all patients (n=62), larger infarct volume was related to higher delta band power in bilateral hemispheres and to higher delta band coherence between iM1 and bilateral regions. In chronic stroke, higher delta power bilaterally correlated with better motor status. In subacute stroke, higher delta coherence between iM1 and bilateral areas correlated with poorer motor status. These coherence findings were confirmed in serial recordings from 18 patients in an inpatient rehabilitation facility. Here, interhemispheric coherence between leads overlying iM1 and contralesional M1 was elevated at inpatient rehabilitation facility admission compared with healthy controls (n=22), declining to control levels over time. Decreases in interhemispheric coherence between iM1 and contralesional M1 correlated with better motor recovery. Conclusions— Delta band coherence with iM1 related to greater injury and poorer motor status subacutely, while delta band power related to greater injury and better motor status chronically. Low-frequency oscillations reflect both injury and recovery after stroke and may be useful biomarkers in stroke recovery and rehabilitation.

scholarly journals β-Oscillations Reflect Recovery of the Paretic Upper Limb in Subacute Stroke

2020 ◽  
Vol 34 (5) ◽  
pp. 450-462 ◽  
Author(s):  
Chih-Wei Tang ◽  
Fu-Jung Hsiao ◽  
Po-Lei Lee ◽  
Yun-An Tsai ◽  
Ya-Fang Hsu ◽  
...  
Keyword(s):  
Motor Function ◽  
Upper Limb ◽  
Primary Motor Cortex ◽  
Hand Movement ◽  
Stroke Recovery ◽  
Stroke Survivors ◽  
Healthy Controls ◽  
Functional Changes ◽  
Post Stroke ◽  
Subacute Stroke

Background. Recovery of upper limb function post-stroke can be partly predicted by initial motor function, but the mechanisms underpinning these improvements have yet to be determined. Here, we sought to identify neural correlates of post-stroke recovery using longitudinal magnetoencephalography (MEG) assessments in subacute stroke survivors. Methods. First-ever, subcortical ischemic stroke survivors with unilateral mild to moderate hand paresis were evaluated at 3, 5, and 12 weeks after stroke using a finger-lifting task in the MEG. Cortical activity patterns in the β-band (16-30 Hz) were compared with matched healthy controls. Results. All stroke survivors (n=22; 17 males) had improvements in action research arm test (ARAT) and Fugl-Meyer upper extremity (FM-UE) scores between 3 and 12 weeks. At 3 weeks post-stroke the peak amplitudes of the movement-related ipsilesional β-band event-related desynchronization (β-ERD) and synchronization (β-ERS) in primary motor cortex (M1) were significantly lower than the healthy controls (p<0.001) and were correlated with both the FM-UE and ARAT scores (r=0.51-0.69, p<0.017). The decreased β-ERS peak amplitudes were observed both in paretic and non-paretic hand movement particularly at 3 weeks post-stroke, suggesting a generalized disinhibition status. The peak amplitudes of ipsilesional β-ERS at week 3 post-stroke correlated with the FM-UE score at 12 weeks (r=0.54, p=0.03) but no longer significant when controlling for the FM-UE score at 3 weeks post-stroke. Conclusions. Although early β-band activity does not independently predict outcome at 3 months after stroke, it mirrors functional changes, giving a potential insight into the mechanisms underpinning recovery of motor function in subacute stroke.

scholarly journals Primary motor cortex neurons classified in a postural task predict muscle activation patterns in a reaching task

2016 ◽  
Vol 115 (4) ◽  
pp. 2021-2032 ◽  
Author(s):  
Ethan A. Heming ◽  
Timothy P. Lillicrap ◽  
Mohsen Omrani ◽  
Troy M. Herter ◽  
J. Andrew Pruszynski ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Muscle Activation ◽  
Primary Motor Cortex ◽  
Network Connectivity ◽  
Spatiotemporal Patterns ◽  
Neural Population ◽  
Activation Patterns ◽  
Reaching Task ◽  
Muscle Activation Patterns ◽  
Muscle Groups

Primary motor cortex (M1) activity correlates with many motor variables, making it difficult to demonstrate how it participates in motor control. We developed a two-stage process to separate the process of classifying the motor field of M1 neurons from the process of predicting the spatiotemporal patterns of its motor field during reaching. We tested our approach with a neural network model that controlled a two-joint arm to show the statistical relationship between network connectivity and neural activity across different motor tasks. In rhesus monkeys, M1 neurons classified by this method showed preferred reaching directions similar to their associated muscle groups. Importantly, the neural population signals predicted the spatiotemporal dynamics of their associated muscle groups, although a subgroup of atypical neurons reversed their directional preference, suggesting a selective role in antagonist control. These results highlight that M1 provides important details on the spatiotemporal patterns of muscle activity during motor skills such as reaching.

Intraoperative validation of functional magnetic resonance imaging and cortical reorganization patterns in patients with brain tumors involving the primary motor cortex

1999 ◽  
Vol 91 (2) ◽  
pp. 238-250 ◽  
Author(s):  
Javier Fandino ◽  
Spyros S. Kollias ◽  
Heinz G. Wieser ◽  
Anton Valavanis ◽  
Yasuhiro Yonekawa
Keyword(s):  
Motor Cortex ◽  
Motor Function ◽  
Primary Motor Cortex ◽  
Objective Evaluation ◽  
Cortical Stimulation ◽  
Cortical Reorganization ◽  
Motor Area ◽  
Primary Motor Area ◽  
Content Type ◽  
Fine Print

Object. The purpose of the present study was to compare the results of functional magnetic resonance (fMR) imaging with those of intraoperative cortical stimulation in patients who harbored tumors close to or involving the primary motor area and to assess the usefulness of fMR imaging in the objective evaluation of motor function as part of the surgical strategy in the treatment of these patients.Methods. A total of 11 consecutive patients, whose tumors were close to or involving the central region, underwent presurgical blood oxygen level—dependent fMR imaging while performing a motor paradigm that required them to clench and spread their hands contra- and ipsilateral to the tumor. Statistical cross-correlation functional maps covering the primary and secondary motor cortical areas were generated and overlaid onto high-resolution anatomical MR images. Intraoperative electrical cortical stimulation was performed to validate the presurgical fMR imaging findings. In nine (82%) of 11 patients, the anatomical fMR imaging localization of motor areas could be verified by intraoperative electrical cortical stimulation. In seven patients two or more activation sites were demonstrated on fMR imaging, which were considered a consequence of reorganization phenomena of the motor cortex: contralateral primary motor area (nine patients), contralateral premotor area (four patients), ipsilateral primary motor area (two patients), and ipsilateral premotor area (four patients).Conclusions. Functional MR imaging can be used to perform objective evaluation of motor function and surgical planning in patients who harbor lesions near or involving the primary motor cortex. Correlation between fMR imaging findings and the results of direct electrical brain stimulation is high, although not 100%. Based on their study, the authors believe that cortical reorganization patterns of motor areas might explain the differences in motor function and the diversity of postoperative motor function among patients with central tumors.

Sign in / Sign up

Export Citation Format

Share Document