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Neural Plasticity
Volume 2018, Article ID 1318093, 10 pages
https://doi.org/10.1155/2018/1318093
Research Article

Aberrances of Cortex Excitability and Connectivity Underlying Motor Deficit in Acute Stroke

1Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
2Department of Medical Imaging, Jinling Hospital, Nanjing University School of Medicine, Nanjing 210002, China
3MR Research, GE Healthcare, Shanghai 201203, China
4State Key Laboratory of Analytical Chemistry for Life Science, Nanjing University, Nanjing 210002, China

Correspondence should be addressed to Zhiqiang Zhang; moc.621@1002qzgnahz and Fang Yang; moc.361@110120gnafgnay

Received 24 March 2018; Accepted 19 June 2018; Published 21 October 2018

Academic Editor: Malgorzata Kossut

Copyright © 2018 Juan Du et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Purpose. This study was aimed at evaluating the motor cortical excitability and connectivity underlying the neural mechanism of motor deficit in acute stroke by the combination of functional magnetic resonance imaging (fMRI) and electrophysiological measures. Methods. Twenty-five patients with motor deficit after acute ischemic stroke were involved. General linear model and dynamic causal model analyses were applied to fMRI data for detecting motor-related activation and effective connectivity of the motor cortices. Motor cortical excitability was determined as a resting motor threshold (RMT) of motor evoked potential detected by transcranial magnetic stimulation (TMS). fMRI results were correlated with cortical excitability and upper extremity Fugl-Meyer assessment scores, respectively. Results. Greater fMRI activation likelihood and motor cortical excitability in the ipsilesional primary motor area (M1) region were associated with better motor performance. During hand movements, the inhibitory connectivity from the contralesional to the ipsilesional M1 was correlated with the degree of motor impairment. Furthermore, ipsilesional motor cortex excitability was correlated with an enhancement of promoting connectivity in ipsilesional M1 or a reduction of interhemispheric inhibition in contralesional M1. Conclusions. The study suggested that a dysfunction of the ipsilesional M1 and abnormal interhemispheric interactions might underlie the motor disability in acute ischemic stroke. Modifying the excitability of the motor cortex and correcting the abnormal motor network connectivity associated with the motor deficit might be the therapeutic target in early neurorehabilitation for stroke patients.