Postural dependence of reaction time in normal subjects and patients with focal brain lesions.

EMG reaction times (EMG-RTs) of triceps brachii muscle of normal subjects and patients with focal brain lesions were measured at two different positions of the shoulder joint. The difference of EMG-RTs between the two positions was smaller in patients with VL-thalamotomy, cerebellar or frontal premotor lesions than in normal subjects and patients with hemiplegia. It is assumed that cerebellum, VL-nucleus and the premotor area are related to the proprioceptive control of RTs.