Effects of prefrontal lesions on left leg-right leg differentiation in dogs.

Twenty five animals trained in the left leg-right leg differentiation were given orbital, proreal or medial precruciate lesions. Pure cortical ablations did not affect the task whereas these deep lesions involving the bundle of fibers inside the prefrontal region caused severe deficit. The medial lesions (superficial and deep) produced disinhibition of the intertrial reactions. The nature of the deficit in the differentiation and the relation between this deficit and the disinhibition is discussed.