Functional Diversity of Subicular Principal Cells during Hippocampal Ripples

Abstract

Cortical and hippocampal oscillations play a crucial role in the encoding, consolidation, and retrieval of memory. Sharp-wave associated ripples have been shown to be necessary for the consolidation of memory. During consolidation, information is transferred from the hippocampus to the neocortex. One of the structures at the interface between hippocampus and neocortex is the subiculum. It is therefore well suited to mediate the transfer and distribution of information from the hippocampus to other areas. By juxtacellular and whole-cellrecordings in awake mice, we show here that in the subiculum a subset of pyramidal cells is activated, whereas another subset is inhibited during ripples. We demonstrate that these functionally different subgroups are predetermined by their cell subtype. Bursting cells are selectively used to transmit information during ripples, whereas the firing probability in regular firing cells is reduced. With multiple patch-clamp recordings in vitro, we show that the cell subtype-specific differences extend into the local network topology. This is reflected in an asymmetric wiring scheme where bursting cells and regular firing cells are recurrently connected among themselves but connections between subtypes exclusively exist from regular to bursting cells. Furthermore, inhibitory connections are more numerous onto regular firing cells than onto bursting cells. We conclude that the network topology contributes to the observed functional diversity of subicular pyramidal cells during sharp-wave associated ripples.

Propagation of Hippocampal Ripples to the Neocortex by Way of a Subiculum-Retrosplenial Pathway

“…Subicular bursting cells are strongly activated during SPW-R events 74 . The relation between burst propensity of neurons in vivo and SPW-R modulation was previously quantified in intracellular recordings based on the unambiguous bursting pattern following rheobase current injection 74 . However, this relation is less clear in extracellular recordings, where spike autocorrelograms (ACGs) are used to quantify the extent of complex spike bursts.…”

“…Slices from the RSC or subiculum were prepared from mice as described previously 74 . In brief, the animals (n = 12 VGlut2-Cre mice; 11 males, 1 female; age: 2-3 months) were deeply anesthetized with isoflurane, decapitated and the brains removed.…”

High-throughput microcircuit analysis of individual human brains through next-generation multineuron patch-clamp

“…This is not only due to more patch attempts, but also 18 due to the increased risk of losing established recordings through mechanical interference or 19 deterioration of recording quality during the prolonged total time of approaching and patching 20 cells. To quantify this observation and provide an estimate for the performance of different 21 setup configurations, we analysed our multipatch experiments on rodent slices from previous 22 and ongoing studies without pipette cleaning(Böhm et al, 2015; Peng et al, 2017). For the 23 performance analysis, we focused on rodent experiments to present an applicable use case 24 for other labs which are not working with human slices.…”

Dynamical modulation of theta-gamma coupling during REM sleep

“…The subiculum is the primary output of the hippocampus, as subicular pyramidal cells send projections to many brain structures including cortical, thalamic, hypothalamic, and septal nuclei 36,37 . Regular-spiking and bursting cells are two distinct classes of subicular pyramidal neurons with possibly different functions 38,39 . Subicular UG, which is important for robust information transfer 40 , is generated by the activation of bursting cells while regular-spiking neurons are inhibited 39,41 .…”