Beta oscillations during adaptation to inertial and velocity dependent perturbations

Movements are associated with a beta (15-30 Hz) power decrease during movement preparation and a rebound after its termination. Motor learning and practice are characterized by an increase of the rebound. However, the introduction of a sensorimotor perturbation negatively affects such measure. In this preliminary study, we investigated whether two learning processes affect beta electroencephalographic activity: (a) learning to perform a center-out reaching task by moving a passive robotic arm, and (b) learning to reach the same targets in the presence of a velocity-dependent force field. Seven subjects were exposed to the (a), then to the (b) condition. Results revealed that beta power rebound and its latency increased with practice with the passive manipulandum. When the force field was applied, beta power rebounded and its latency immediately dropped, but they started to increase again with the prolonged exposure to the predictable perturbations. These results suggest that increased rebound in beta power reflects cortical activity elicited by the correct prediction of movement outcomes.