Communication between neocortex and hippocampus during sleep in rodents

TLDR

Neocortical and hippocampal networks use sleep oscillations to organize neuronal firing, yet the functional role of these rhythms and their potential importance for memory consolidation remain unclear. The study hypothesizes that oscillation‑mediated temporal links coordinate information transfer between neocortical and hippocampal cell assemblies. Neuronal discharges in the somatosensory cortex and hippocampus are tightly correlated across slow and fine timescales, with deep cortical bursts linked to sleep spindles and delta waves triggering hippocampal ripple‑related discharges.

Abstract

Both neocortical and hippocampal networks organize the firing patterns of their neurons by prominent oscillations during sleep, but the functional role of these rhythms is not well understood. Here, we show a robust correlation of neuronal discharges between the somatosensory cortex and hippocampus on both slow and fine time scales in the mouse and rat. Neuronal bursts in deep cortical layers, associated with sleep spindles and delta waves/slow rhythm, effectively triggered hippocampal discharges related to fast (ripple) oscillations. We hypothesize that oscillation-mediated temporal links coordinate specific information transfer between neocortical and hippocampal cell assemblies. Such a neocortical–hippocampal interplay may be important for memory consolidation.