The cerebellum is involved in predicting the sensory consequences of action

We used (H2O)-O-15 PET to examine neural responses to parametrically varied degrees of discrepancy between the predicted and actual sensory consequenc es of movement. Subjects used their right hand to move a robotic arm. The m otion of this robotic arm determined the position of a second foam-tipped r obotic arm, which made contact with the subject's left palm. Using this rob otic interface, computer controlled delays were introduced between the move ment of the right hand and the tactile stimulation on the left. Activity in the right lateral cerebellar cortex showed a positive correlation with del ay. These results suggest the cerebellum is involved in signalling the sens ory discrepancy between the predicted and actual sensory consequences of mo vements. NeuroReport 12:1879-1884 (C) 2001 Lippincott Williams & Wilkins.