CHOLINE-ACETYLTRANSFERASE MESSENGER-RNA PLASTICITY WITH PAVLOVIAN CONDITIONING

Choline acetyltransferase mRNA and somal area increased selectively in the ventral nucleus basalis of rats trained that a tone signals immed iate shock (i.e., predicts danger). Retrograde tracing showed the affe cted cells correspond to those that project to the auditory cortex. Be havior responses and mRNA increased significantly above those of contr ol groups trained with the tone not signaling immediate shock. In one of those control groups, animals learned that the same tone signaled a shock-free period before shock, These animals showed a visibly decrea sed riboprobe and a trend toward smaller somal areas. These results im plicate transcriptional regulation of choline acetyltransferase in lon g-term memory storage. Selective attention and inattention to the tone are possible components of memory encoded by the molecular changes re ported here. (C) 1996 Academic Press, Inc.