Electrocorticographic spectral changes associated with ipsilateral individual finger and whole hand movement.

The study of the human sensorimotor (SM) cortex activations associated with hand motor movement is central to the design of efficient and clinically useful brain-computer interfaces. Whereas the electrocorticographic (ECoG) signatures of contralateral hand movement have been studied in detail, those of ipsilateral hand and individual finger movements have not been characterized. We studied the low (8-32 Hz) and high-frequency (76-100 Hz) SM cortical ECoG spectral changes associated with contralateral and ipsilateral whole hand and individual finger movement and assessed their discriminability. We find that ipsilateral movement is associated with widespread decreases in the low-frequency band (LFB) and more focal increases in the high-frequency band (HFB). The HFB component discriminates between ipsilateral and contralateral movement-associated activations, in contrast to the LFB. The HFB also discriminates between thumb and index finger movement-associated activations, for both the contralateral and the ipsilateral case, whereas the LFB does not. This is the first published report of a discriminable ipsilateral motor signal, with important implications in the use of brain-computer interfaces in hemiplegic patients.