Control of velocity in the sensorimotor area during a visually guided joystick movement: A high-density EEG study

Abstract

The sensorimotor area in cerebral cortex is involved in processing visual motion information and the subsequent execution of visually guided hand movements. Electroencephalogram (EEG) recordings of 10 adult subjects were applied to examine the brain electrical activity accompanying a visually guided joystick movement intercepting with a moving target. While the velocity of the target varied, the direction of the joystick movement was constant and it was expected that increased stimulus` velocity would be accompanied with larger EEG activity. The EEG data analysis showed that a positive potential, evolving across the medial frontal – posterior region, immediately succeeded the joystick movement. The source model indicated that the activity primarily could be explained by two dipoles, one located medial in the sensorimotor area and another one in the visual areas in the occipital lobe. Further, by increasing the stimulus` velocity the EEG activity in the sensorimotor area also increased. The corresponding relationship between the movement–related potentials (MRP) and the velocity of the stimulus indicate that the sensorimotor area is involved in controlling velocity, which can apply to both visual motion processing and the execution of the motor response. However, the positive potential did not evolve until the actual joystick movement began suggesting that the MRPs reflect neural activity participating in the motor response in which the differentiated EEG activity can be related to a neural network in the sensorimotor area responding to increased velocity by gradually increasing the discharge rate.