The progresion of change in neuronal activity that underlie the formation and consolidation of a gustatory associative memory
Fri-S7-005
Presented by: Anan Moran
Memory formation is not an instantaneous event, but rather a dynamic process that progressively evolves. Notable phases of memory formation include the early acquisition in which the memory is still labile, and the consolidation phase wherein the memory stabilizes. In conditioned taste aversion (CTA) learning, for instance, two such phases were identified in the gustatory cortex (GC) during the formation of a taste-malaise memory: an early acquisition phase (2-3 hours following training), followed by a consolidation phase 3 hours later. While these memory phases were characterized by their underlying molecular underpinnings, their associated progression in neuronal activity, neuronal network connectivity, and neuronal coding of taste identity, palatability, and novelty is still largely unknown. To study these unknowns we record continuously from the GC of rats while they undergo CTA. We found that the progression of activity changes depends on the neuronal organizational level: whereas the population response changed continuously, the known quickening of the ensemble-state dynamics associated with the faster rejection of harmful foods appeared only after consolidation. These results suggest a role of the consolidation phase in network optimization. In a new set of experiments we aim to characterize the network-level connectivity map and the cell-specific coding changes that underlie the progression of the CTA memory. To that end we implant Neuropixels probes in the GC and neighboring brain regions, and record the activity of hundreds of neurons simultaneously before, during, and after CTA. Using generalized linear modeling techniques over the pairwise neuronal cross-correlation we set to characterize the connectivity map between the recorded neurons. Creating this map during different time points following CTA will allow us to portray the fine network functional connectivity changes that underlie early acquisition and late consolidation phases.