Dynamics of EEG Synchronization and Desynchronization on Execution of Real and Imaginary Hand Movements Towards a Visible Target

This paper reports studies of the cortical organization of the real and imaginary execution of a hand movement aimed at a target. Six independent sources of electrical activity were identified in the EEG recordings. These sources corresponded to the premotor areas, supplementary motor area, primary motor areas, and posterior parietal cortex. Activation patterns in the α and β ranges were studied by continuous wavelet transformation. The main differences between real and imaginary execution of the movement were found in the activation of the primary motor and premotor areas. Asymmetry in the activation of the primary motor areas was seen only during imaginary movements. Desynchronization of the premotor areas in both the α and β ranges, corresponding to activation of these areas, accompanied imaginary movements throughout their entire duration. Hypersynchronization, corresponding to inhibition, was seen in these areas during real movements, while desynchronization was seen in the latent period of 1.5 sec before the onset of the movement. Thus, imaginary movements had features of the planning of real movements.