Functional correlates of incoordination in patients with spinocerebellar ataxia 1: a preliminary fMRI study

The neural (blood oxygenation level dependent) correlates of motor coordination of both hands were studied in adult right-handed volunteers and patients with spinocerebellar ataxia 1 (SCA1), using functional magnetic resonance imaging (fMRI) of the entire brain. Each experimental condition consisted of five sets of alternate pronation and supination tasks for either hand in a prescribed sequence as the active phase followed by a period of rest. An intricate network consisting of sensorimotor cortex, supplementary motor area (SMA), cingulate motor area (CMA), putamina and cerebellum, was identified when the task was performed in healthy volunteers. However, cerebellar activity was largely absent with additional activity in contralateral cortices and in thalami in patients with SCA1. This apparent decoupling of sensorimotor cortical and cerebellar areas during coordinated movement in patients with SCA1, suggests that cortico-cerebellar loops may be malfunctioning in SCA1.