Sleep Spindles Promote the Restructuring of Memory Representations in Ventromedial Prefrontal Cortex through Enhanced Hippocampal–Cortical Functional Connectivity

• DOI: 10.1523/jneurosci.1946-19.2020
• Publication Date: 2020-01-20T22:49:21Z
• Authors: Emily Cowan; Anli Liu; Simon Henin; Sanjeev Kothare; Orrin Devinsky; Lila Davachi
• Keywords: Ventromedial prefrontal cortex; Sleep spindle

Memory consolidation is hypothesized to involve the distribution and restructuring of memory representations across hippocampal cortical regions. Theories suggest that, through extended hippocampal–cortical interactions, ensembles come represent more integrated, or overlapping, traces that prioritize commonalities related memories. Sleep processes, particularly fast sleep spindles, are thought support consolidation, but evidence for this relationship has been mostly limited retention benefits. Whether spindles provide a mechanism neural changes including strengthening networks integration representations, remains unclear, as does specificity regions involved. Using functional connectivity analyses human fMRI data (both sexes), we show spindle density during overnight enhanced next day, when restudying information learned before sleep. Spindle modulated in distinct depending on category consolidated stimuli. Specifically, correlated with between anterior hippocampus ventromedial prefrontal cortex (vmPFC) object–word pairs, posterior posteromedial scene–word pairs. multivariate pattern analyses, also postlearning associated greater similarity, representational overlap, individual memories vmPFC day. Further, overlap was mediated by degree hippocampal–vmPFC connectivity. Together, these results network traces, potentially vmPFC. SIGNIFICANCE STATEMENT How new experiences transformed into long-term fundamental question neuroscience research. stabilized they reorganized brain, process be supported oscillations, spindles. Although have benefits retention, it not well understood how modify traces. This study found correlate increased similarity among cortex. The critical may act physiological