Arndt, Kaiser C.Gilbert, Earl T.Klaver, Lianne M.F.Kim, JongwoonBuhler, Chelsea M.Basso, Julia C.McKenzie, SamEnglish, Daniel Fine2024-06-072024-06-072024-03-26https://hdl.handle.net/10919/119344The granular retrosplenial cortex (gRSC) exhibits high-frequency oscillations (HFOs; ~150 Hz), which can be driven by a hippocampus-subiculum pathway. How the cellular-synaptic and laminar organization of gRSC facilitates HFOs is unknown. Here, we probe gRSC HFO generation and coupling with hippocampal rhythms using focal optogenetics and silicon-probe recordings in behaving mice. ChR2-mediated excitation of CaMKII-expressing cells in L2/3 or L5 induces HFOs, but spontaneous HFOs are found only in L2/3, where HFO power is highest. HFOs couple to CA1 sharp wave-ripples (SPW-Rs) during rest and the descending phase of theta. gRSC HFO current sources and sinks are the same for events during both SPW-Rs and theta oscillations. Independent component analysis shows that high gamma (50–100 Hz) in CA1 stratum lacunosum moleculare is comodulated with HFO power. HFOs may thus facilitate interregional communication of a multisynaptic loop between the gRSC, hippocampus, and medial entorhinal cortex during distinct brain and behavioral states.16 pagesapplication/pdfenCreative Commons Attribution 4.0 InternationalArticle - Refereedhttps://doi.org/10.1016/j.celrep.2024.11391043