Distinct movement related changes in EEG and ECeG power during finger and foot movement

Voluntary movement is known to be associated with cerebrally generated movement-related slow potentials and parallel changes in spectral power. The cerebellar and cerebral cortices are powerfully connected via reciprocal, crossed projections which mediate their coordination in motor, as well as cognitive and affective processes. The cerebellum participates in movement and the question remains as to the nature of movement related changes in power if any which might occur over the cerebellum. In a sample of six healthy adult subjects, we recorded EEG and the electro-cerebellogram (ECeG) with a 10 % cerebellar extension montage during voluntary left and right index finger and foot movements. EMG was recorded from finger extensors and flexors and from the tibialis anterior and soleus muscles and was used to generate triggers for movement related averaging (-2000 to + 2000 ms). Wavelet power was computed over the 4 s epoch for each electrode. For statistical analysis, cerebral and cerebellar grids centred around Cz and SIz were investigated, using both average and linked-ear references. Statistically significant movement related changes were observed in both cerebral and cerebellar power, most significantly in the high delta band (1.5 to 3 Hz), for both montages. In contrast to Cz where power increased premovement, power was reduced over the cerebellum. High-frequency pause-bursting was also observed in the ECeG around the time of movement. Our results indicate that recordings over the cerebellum show distinct changes from those over Cz and in particular show a fall in power during the premovement period.