REGIONAL CEREBRAL BLOOD-FLOW DURING A SELF-PACED SEQUENTIAL FINGER OPPOSITION TASK IN PATIENTS WITH CEREBELLAR DEGENERATION

The brain regions controlling self-paced sequential finger movements i n patients with cerebellar degeneration were studied by measuring chan ges in regional cerebral blood flow (rCBF) in eight patients using bol us injections of (H2O)-O-15 and PET The results were compared with tho se obtained in eight normal age-matched control subjects. Patients and control subjects performed a self-paced sequential finger opposition task with the right hand, completing a sequence of movements every 4-6 s. Both groups had strong increases in the adjusted rCBF contralatera lly in the primary motor cortex (M1) and ventral premotor area (PMv), in the caudal supplementary motor area (SMA) and cingulate motor area (CMA), and bilaterally in the prefrontal cortex (PFC), the lobus parie talis inferior (LPI), putamen and cerebellum. The cerebellum, PMv, ros tral CMA, PFC and LPI were move active in the control subjects than in the patients, and the M1, SMA, caudal CMA and putamen were more activ e in the patients than in the control subjects. The reduced activity o f the cerebellar neurons in the patients produced a complex pattern of rCBF increases and decreases in other brain regions. Our results sugg est that for the preparation and execution of sequential finger moveme nts, patients with cerebellar degeneration use a medial premotor syste m, including the SMA and caudal CMA, as well as the MI and putamen, ra ther than the PMv, PFC, LPI and rostral CMA.