The right sound at the right time: Cerebellar and ventral striatal involvement in imitating pitch and timing

Acting on the world requires the right action at the right time. This is perhaps most easily seen in music where the meaning of a piece is encoded explicitly by both the pitches of musical notes and their duration. We used these features to operationalise the production of desired qualia of movements as note pitches as compared to movement timing as note durations. Participants listened to and imitated simple melodies as accurately as possible while lying in an ultra-high field 7T MRI scanner. Melodies consisted of either a series of different pitches of equal duration or a single pitch repeated at different durations. Both tasks engaged a broad motor network similar to speech and other complex dynamic movements. However, imitation for timing preferentially activated the ventral striatum of the basal ganglia while imitation for pitch preferentially activated lobule VI of the cerebellum and temporal lobe auditory association areas. These findings are consistent with the role of the basal ganglia in sound sequence learning and with the role of the cerebellum in refining movement based on sensory feedback. Imitating melodies provides a simple but effective framework for manipulating the qualities and timings of sound production by the speech-motor system, even when no words are spoken.