[Role of the cerebellum in the control of distal motor activities in patients with akinetic-rigid Parkinson disease].

Using f-MRI, we have studied the changes induced by the performance of a complex sequential motor task in the cortical areas of nine akinetic PD patients and compared to that of healthy volunteers. Compared with normal subjects, PD patients showed a reduction of activation of motor and SMA areas, an increase of activation of parietal areas and a bilateral activation of cerebellar hemispheres, which are likely to participate in the attempt to recruit parallel motor circuits in order to overcome the striatocortical defective loop.