Effect of Unilateral Non-Rhythmical Stimulation on Bilateral Cerebral Cortex and Muscle Activation in People

Effects of conventional exercise training of robot to stroke patients are not too satisfying, and efficient methods of training are unclear. To test how the non-rhythmical load stimulation affects cerebral cortex by analyzing the coherence between electroencephalographic signals (EEGs) and electromyographic signals (EMGs). Ten healthy subjects, all subjects have no history of neurological diseases (6 men and 4 women, mean age: 24.5 years, range: 22-28). Subjects lay on the experimental platform 75°with respect to the ground, feet on support plates and close to the ground. When non-rhythmical stimulation was performed randomly, one hinge was released and the respected braced force between the foot and support plate disappeared, which caused the corresponding ankle to extend suddenly without relative displacement between the foot and the support plate. Surface EMG signals from tibialis anterior (TA) muscles and EEG signals from cerebral cortex area Cz were recorded, and coherence between them were analyzed. The mean maximum EEG-EMG coherence of the non-rhythmical stimulation side of the ten subjects was consistent across all (9 of 10) within β range (13-30 Hz), and the average value of all in the stimulated side was 23.581Hz. While the mean maximum EEG-EMG coherence of the still side were consistent across all (9 of 10) within α range (8-13 Hz). Our findings suggest that non-rhythmical stimulation to lower limb can stimulate effectively the corresponding area of the cerebral cortex, and this idea could be applied in rehabilitation of central nervous system diseases like stroke.