Basal ganglia lesions and psychological analyses of the control of voluntary movement.

Psychological accounts of the voluntary control of movement recognize the contribution of perceptual and decision processes as well as processes such as motor memory and timing that are more obviously a part of motor control. A model including these and other components is outlined in relation to tracking, a task that has often been used to study human perceptual-motor performance. The need for experimental control in addressing such multi-process models is emphasized. A number of studies of perceptual-motor performance deficits in patients with Parkinson's disease are reviewed. The methods by which the studies relate the behavioural data to the hypothesized underlying processes may be broadly grouped according to whether they use a subtractive logic or take a decompositional approach. These studies suggest that the basal ganglia play a role in the activation of pre-planned movement.