Distinct contribution of the striatum and cerebellum to motor learning

The striatum and cerebellum have been shown to be kev structures of a distr ibuted system For the control of skilled movements. However, the mechanisms under which they operate remain unclear. This study compared the performan ce of patients with Parkinsons disease (PD) or with cerebellar damage (CE) to that of age-matched controls. Each group performed two visuomotor paradi gms: a random variant of the serial reaction time (SRT) task that tested th e subject's ability To make efficient stimulus-response associations and an adapted version of the mirror-tracing task that measured their capacity to combine simple movements into complex ones. PD patients with bilateral str iatal damage showed an impaired learning profile on the SRT task and a norm al facilitation effect in the tracing task, while CE patients showed the re verse pattern. Although further research is needed, the present findings su ggest that the striatum and cerebellum are involved in distinct learning me chanisms. (C) 2001 Academic Press.