Postural dependence of reaction time after a VL thalamotomy.

Postural dependence of the EMG-RT of the triceps brachii muscles was measured in 68 parkinsonian patients of which 38 underwent a ventrolateral thalamotomy. A thalamotomy did not affect patients' EMG-RT per se, but it changed the postural dependence of the EMG-RT. After left thalamotomy the position changes of both shoulders did not influence the EMG-RT of the right triceps, and after right thalamotomy the position change of the left shoulder had no influence on the EMG-RT of both triceps. As for the sensorimotor function, it is assumed that the right thalamus has bilateral control on the input system and the left thalamus has bilateral control on the output system.