Gamma band activity associated with BCI performance – Simultaneous MEG/EEG study

While brain computer interface (BCI) can be employed for patients and healthy subjects, there are problems that must be resolved before BCI can be useful to the public. In the most popular motor imagery BCI system, a significant number of target users (called BCI-Illiterates) cannot modulate their neuronal signals enough to use the BCI system. This causes performance variability among subjects and even among sessions within a subject. The mechanism of such BCI-Illiteracy and possible solutions still remain to be determined. Gamma oscillation is known to be involved in various fundamental brain functions, and may play a role in motor imagery. In this study, we investigated the association of gamma activity with motor imagery performance among subjects. Ten simultaneous MEG/EEG experiments were conducted; motor imagery performance for each was estimated by EEG data, and the gamma activity associated with BCI performance was investigated with MEG data. Our results showed that gamma activity had a high positive correlation with motor imagery performance in the prefrontal area. This trend was also found across sessions within one subject. In conclusion, gamma rhythms generated in the prefrontal area appears to play a critical role in BCI performance