Changes in the human brain during rhythm learning

Subjects were scanned with PET while they learned a complex arbitrary rhyth m, paced by visual cues. In the comparison condition, the intervals were va ried randomly. The behavioral results showed that the subjects decreased th eir response time with training, thus becoming more accurate in responding to the pacing cues at the appropriate time. There were learning-related inc reases in the posterior lateral cerebellum (lobule HVIIa), intraparietal an d medial parietal cortex, presupplementary motor area (pre-SMA), and latera l premotor cortex. Learning-related decreases were found in the prestriate and inferior temporal cortex, suggesting that with practice the subjects in creasingly came to depend on internal rather than external cues to time the ir responses. There were no learning-related increases in the basal ganglia . It is suggested that it is the neocortical-cerebellar loop that is involv ed in the timing and coordination of responses.