| Popis: |
Memories vary in many dimensions, including the level of detail for behaviorally relevant sensory cues. Memory exists along a continuum from highly cue-specific to highly generalized, which is likely due to individual differences in experience-dependent plasticity. This dissertation had two broad objectives: (1) To determine the neurophysiological substrates of memory specificity and (2) to induce these substrates through pharmacological inhibition of the epigenetic regulator histone deacetylase 3 (HDAC3). Adult male rats were trained in three different auditory operant tasks, with an HDAC3 inhibitor administered in a post-session design. Sound-evoked auditory responses were recorded to determine forms of experience-dependent auditory representational plasticity that are associated with memory specificity. Results revealed that, despite differences in task structure, the identity of behaviorally relevant sound features, and the neural coding strategy used to represent sound features, a signal-specific pattern of auditory RP was associated with sound-specific memory. Indeed, individual differences in auditory RP predict the degree of specificity with which memory is formed. Further, despite differences in task and stimulus identity, HDAC3 inhibition enabled the formation of unusually specific auditory long-term memory. Together, results identify pharmacological manipulation of epigenetic regulators like HDAC3 as tools to gain control of memory specificity and to reveal its neural substrates. Using these tools, we implicate sensory systems as critical participants in cognitive processes like memory formation, from a systems level perspective and molecular epigenetic level. |
