Electrocorticographic signals comparison in sensorimotor cortex between contralateral and ipsilateral hand movements

Brain machine interfaces (BMIs) have emerged as a technology to restore lost functionality in motor impaired patients. Most BMI systems employed neural signals from contralateral hemisphere. But many studies have also demonstrated the possibility to control hand movement using signals from ipsilateral one. However, the relationship of neural signals in sensorimotor cortex between contralateral and ipsilateral hand movement control is still unclear. In this study, the electrocorticographic signals (ECoG) of sensorimotor cortex were analyzed in two epilepsy participants when they performed a visual guided rock-scissors-paper task by using contralateral and ipsilateral hand respectively. Although typical beta suppression followed increased gamma were observed during the movements of each individual hands, the stronger responses were found in two participants when their contralateral hands were used during the task. We further extracted the power spectrum of high gamma frequency band (70-135Hz) of ECoG signals as neural features to decode the hand movements. The results showed that the classification accuracy of contralateral decoding and ipsilateral decoding were 81% and 78% for participator one (P1) and 84% and 77% for participator two (P2). The accuracy of ipsilateral decoding was only slightly lower than that of contralateral one. The hand movement information contained in ipsilateral sensorimotor cortex suggested that the ipsilateral hemisphere might be also involved in neural modulation as well as contralateral hemisphere did when performing unimanual movement, which would expand the clinical application of BMIs.