Molecular correlates of multiday memory in an appetitive conditioning model: insights into mediators of memory extension

Abstract

These experiments provide insight into potential mediators implicated in the maintenance of memory duration using an olfactory preference learning paradigm. Neonatal rats were trained in a single training session by pairing odor (CS) with pharmacological agents (UCS) to promote odor preference of different durations (24h, 4-Day and 5-Day). For the first time in olfactory preference learning we characterize the pCREB expression profile as biphasic with peaks at 10min and 2h post-conditioning in 24h and 5-Day olfactory preference memory. Second, we show histone acetylation is enhanced by HDAC inhibition via NaB in both learning and non-learning conditions. Finally, q-PCR reveals CREB target genes Nr4a1 and Egr-1 are differentially expressed across 24h and 5-Day models, consistent with a possible role in memory extension. These experiments support CREB as a possible initiator in mediating downstream events leading to the changes in synaptic plasticity that accompany extension of long-term memory.