Impairment of motor imagery in putamen lesions in humans.

Patients with putamen or cortical lesions participated in a first- and third-person movement imagery task, each primarily engaging kinesthetic and visual imagery. The subjects were instructed to imagine themselves (first-person task) and a third party (third-person task) performing a sequence of three movements and to choose from a set of four photos the end posture resulting from the movements. The results demonstrated that, limb-specific imagery was impaired in both putamen and cortical lesions, in the first-, but not third-person task. Moreover, more than half of the errors made by cortical patients were with respect to the first movement, a finding consistent with motor cortex involvement in memory processes. Taken overall, the results provide evidence that the basal ganglia as well as cortical structures play an important role in the neural network mediating motor imagery.