Dynamics of EEG synchronization and desynchronization when performing real and imagined hand reaching

The work investigates spatial and temporal EEG patterns during real and imagined execution of hand reaching. Six independent sources of electrical activity were identified in the EEG recordings. The sources corresponded to the premotor areas, supplementary motor area, primary motor areas, and posterior parietal cortex. Their activation patterns in the alpha and beta range were studied using a continuous wavelet transform. The main differences between real and imagined movement are found in the activation of primary motor and premotor areas. Asymmetry in activation of primary motor areas was observed only during the imaginary movements. Desynchronization in premotor areas of both the alpha and beta ranges, suggesting their activation, accompanied the imaginary movements throughout their course. On the other hand, hypersynchronization was observed in premotor areas during real movement, which likely corresponds to inhibition, while desynchronization was observed in the latent period, 1.5 seconds before the start of movement. Thus, an imaginary movement bears the features of planning a real movement.