Abstract Rats were trained on a taste aversion task in which they were given access to water and saccharin on alternate days. Saccharin consumption was followed by an injection of apomorphine which made the animals ill. In the first experiment the animals learned to avoid drinking saccharin under unilateral cortical spreading depression (CSD) and showed a marked transfer when tested with the contralateral hemisphere depressed. In the second experiment rats were successfully trained on the same task under bilateral CSD. The data indicate that the afferent, efferent, and association process necessary for the maintenance of fluid intake and the regulation of that intake by conditioned aversive properties of taste stimuli do not depend upon normally functioning neocortex.