Transcriptomic Signatures of Hippocampal Active Place Avoidance Memory Maintenance

Surprisingly, these gene expression enrichments were not observed in eYFP mRNA positive spatial spots. To gain granularity into this finding, we carried out single nuclear RNA sequencing, which confirmed enrichment of differentially expressed genes associated with synaptic plasticity and post-synaptic signaling unique to each subregion in trained animals, but not from their eYFP mRNA positive nuclei. Notably, nuclei of hippocampal neurons were largely characterized by their down regulation of genes involved in ATP synthesis and cytoplasmic translation.

Our results suggest that two overarching transcriptomic patterns contribute to the functional changes in hippocampal cells during offline memory maintenance: regionally distributed expression of genes linked to synaptic functions (with concomitant sparseness of memory-associated neuronal ensembles) and a reduction of metabolic activity related genes across hippocampal sub-regions.