Role of the insular cortex in morphine-induced conditioned taste avoidance.

The present study investigated the role of the insular cortex (IC) in morphine-induced conditioned taste avoidance. The results of Experiment 1 revealed that IC lesions impaired taste neophobia, retarded acquisition of conditioned saccharin avoidance and apparently attenuated the magnitude of that response at asymptote. Using neurologically intact subjects, Experiment 2 established that a safe and familiar saccharin stimulus supports substantially weaker conditioned avoidance at asymptote than does a potentially dangerous and novel saccharin stimulus. This pattern of results does not support the hypothesis that IC lesions disrupt the learning mechanism responsible for morphine-induced conditioned taste avoidance. The data are, however, consistent with the hypothesis that IC lesions impair the perception of the danger and/or novelty of the taste stimulus.