TRANSFER OF FUNCTION TO A SPECIFIC AREA OF THE CORTEX AFTER INDUCED RECOVERY FROM BRAIN-DAMAGE

Different methods of inducing recovery after brain damage and different mechanisms that might mediate the induced recovery have been proposed. One possible mechanism involves the ability of one part of the brain to take over the function of another. We show here in rats that (1) bar-pressing behaviour to eliminate an aversive stimulus, which becomes dramatically impaired after bilateral lesion of the frontal primary motor - sensory cortex, is recovered when the animals receive an electrical intracranial stimulation in the ventral tegmental nucleus of the brain contingent on an adequate response during performance in the behavioural task, (2) in recovered animals an area in the posterior primary motor-sensory cortex, the hindlimb motor-sensory cortex, shows a 35% increase in the number of fos-like immunoreactive cells compared to non-recovered animals, and (3) a bilateral lesion of this area in recovered animals reinstates the impairment in the performance of the behavioural task. These results indicate that an area of the cerebral cortex is able to assume the role of another area after induced recovery from brain damage.