OBSERVATIONS ON MONKEYS WITH BILATERAL LESIONS OF THE GLOBUS PALLIDUS

Wilson 1 made unilateral lesions in the lentiform nucleus of monkeys, which were then kept under observation for about three weeks. Small lesions caused no symptoms. Even when the destruction was extensive tremor or other involuntary movement was not observed. Some of these monkeys, however, showed a preference for using the homolateral limb in grasping food, but there was no real paresis. The symptoms, such as they were, pointed to an impairment of corticospinal fibers, which might be attributed to pressure on, or edema in, the internal capsule associated with the closely adjacent lesion. Wilson's statement "it is therefore conceivable that a large lenticular lesion produces an unsteadying effect in innervation" must be regarded as an impression carried over from his clinical studies rather than a justifiable conclusion drawn from the results of his experiments. Lewy 2 made bilateral lesions in the lentiform nucleus of monkeys by inserting a knife