Role of heterogeneous pyramidal cell populations and specific connectivity motifs in pattern completion and replay of memory sequences

Hippocampal sharp wave/ripple complexes (SWRs) are short (50–100 ms) episodes of coordinated network activity arising in the hippocampal CA3 area. They mediate the consolidation of explicit memories, and their disruption impairs memory whereas their prolongation enhances memory. However, the mechanisms governing the occurrence of these episodes remain obscure. To better understand SWR dynamics, we will focus on the role of heterogeneous pyramidal cell populations and specific connectivity motifs in pattern completion and replay of memory sequences. We will analyze the differential embedding of CA3 pyramids during SWRs, assess their specific connectivity, manipulate subsets of neurons using optogenetics in vitro and in vivo, and develop computational network models of SWRs that can be numerically simulated and analyzed mathematically. This work will considerably extend our understanding of sharp-wave models, which were established in our joint experimental-theoretical work in the previous funding period.

Image Poster excerpt showing model of interactions between (P) pyramidal cells, PV+ (B) basket cells, and (A) anti-SWR cells. Courtesy of Richard Kempter and Gaspar Cano

Archive – A01 (SFB1315/1)