Active avoidance in rats with unilateral hypothalamic and optic nerve lesions.

During the height of the contralateral sensorimotor deficit that follows unilateral hypothalamic lesions, rats demonstrate severe performance deficits when tested on a two-way active avoidance task which utilizes a visual conditioned stimulus. This deficit is observed whether or not the ipsilateral or contralateral optic nerve is sectioned in conjunction with the unilateral hypothalamic lesion. With the return of sensorimotor function contralateral to the lesion, animals that had been unable to avoid shock during their debillitated phase demonstrated significant savings when tested on the original task.