Modulation of ERD/S by having a conscious target during lower-extremity motor imagery.

Abstract

In the field of neurorehabilitation with brain-computer interfaces (BCIs) technology, an EEG feature, event-related desynchronization/synchronization (ERD/S) caused by motor imagery (MI) is widely used for estimating human motor intention. However, sufficient neurofeedback training is required for the use of the MI-based BCI system, because the ability to generate ERD/S is highly dependent on individuals. To find an effective MI condition for the BCI system, we hypothesize that having a conscious target during MI would enhance the extent of ERD/S. In the experiments, we investigated the individual effect of two types of MIs: leg extension (L) and leg extension with a conscious target (i.e., kicking a ball (KB)) on the resultant ERD/S. We evaluated time-frequency maps of ERD/S and statistically compared these two conditions (i.e., L and KB). As a result, a significant difference was found in beta-ERD (paired t-test, p <; 0.01), while there were no significant differences in mu-ERD and beta-ERS. These results suggest that having a conscious target during lower extremity MI would strengthen the ERD in beta frequency band compared to the case without target.