FACILITATION AND RECOVERY OF SHUTTLE BOX AVOIDANCE-BEHAVIOR AFTER FRONTAL-CORTEX LESIONS IS INDUCED BY A CONTINGENT ELECTRICAL-STIMULATION IN THE VENTRAL TEGMENTAL NUCLEUS

A bilateral ablation of the frontal cortex was performed in rats before and after training in an active avoidance task in a shuttle box. Animals with this lesion showed an impairment in learning and in the reversal of the avoidance task. If the animals with the lesion were implanted with an electrode in the ventral tegmental nucleus and received an electrical stimulation in, this area contingent to a correct response (avoidance or escape response) in the behavioral task, they did not show any impairment in the performance of the task. Furthermore, the effect of the stimulation persisted after it was retrieved. The present findings indicate that the motivational and cue properties of the electrical stimulation of the ventral tegmental nucleus may serve to facilitate learning and reversal in an avoidance task and to induce at the long term a recovery process in animals in which the frontal cortex has been ablated. Therefore, this method may be useful to study the adaptative changes which take place in the nervous system after recovery from brain damage occurs.