Propagation of EEG Activity in the Beta and Gamma Band during Movement Imagery in Humans

Objectives: The objective of the paper was the determination of electrical brain activity propagation in sensorimotor areas during hand movement imagery. Methods: Right-hand and left-hand movement imagination was studied in three subjects. The 10-channel Multivariate Autoregressive Model (MVAR) was fitted to EEG signals recorded from subsets of electrodes overlying central and related brain areas. By means of the Short-time Directed Transfer Function (SDTF) the propagation of brain activity as a function of frequency and time was found. Results: During imagery the relation between propagations in gamma and beta bands changed significantly for electrodes overlying sensorimotor areas, namely the increase in gamma was accompanied by the decrease in the beta band. Conclusions: The hypothesis was put forward that these kinds of changes in flow of electrical brain activity are connected with the specific information processing.