Rat gustatory memory requires protein kinase C activity in the amygdala and cortical gustatory area

We have studied the physiological involvement of protein kinase C (PKC) in the formation of conditioned taste aversion (CTA) by means of microinjections of PKC inhibitors into the gustatory cortex (GC), amygdala (AMY) and thalamic gustatory area at various time-windows of the CTA paradigm. Rats injected between the CS-US interval with PKC inhibitors into the GC and AMY, but not into the thalamic gustatory area, failed to acquire CTA. Injections of PKC inhibitors 4 h after the US presentation or just before the retention test elicited no disruptive effect. Injections of PKC inhibitor into the AMY, but not into the GC, 30 min after the CS-US pairing impaired CTA formation. These results show that PKC activity in the GC and AMY has a key role in the acquisition phase of CTA, but not in the retrieval phase. The findings also suggest that the GC is concerned with information processing of the CS, and that the AMY is involved in the CS-US association.