Feedforward inhibition is randomly wired from individual granule cells onto CA3 pyramidal cells

Máté Neubrandt, Viktor János Oláh, János Brunner, János Szabadics

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Feedforward inhibition (FFI) between the dentate gyrus (DG) and CA3 sparsifies and shapes memory- and spatial navigation-related activities. However, our understanding of this prototypical FFI circuit lacks essential details, as the wiring of FFI is not yet mapped between individual DG granule cells (GCs) and CA3 pyramidal cells (PCs). Importantly, theoretically opposite network contributions are possible depending on whether the directly excited PCs are differently inhibited than the non-excited PCs. Therefore, to better understand FFI wiring schemes, we compared the prevalence of disynaptic inhibitory postsynaptic events (diIPSCs) between pairs of individually recorded GC axons or somas and PCs, some of which were connected by monosynaptic excitation, while others were not. If FFI wiring is specific, diIPSCs are expected only in connected PCs; whereas diIPSCs should not be present in these PCs if FFI is laterally wired from individual GCs. However, we found single GC-elicited diIPSCs with similar probabilities irrespective of the presence of monosynaptic excitation. This observation suggests that the wiring of FFI between individual GCs and PCs is independent of the direct excitation. Therefore, the randomly distributed FFI contributes to the hippocampal signal sparsification by setting the general excitability of the CA3 depending on the overall activity of GCs.

Original languageEnglish
Pages (from-to)1034-1039
Number of pages6
JournalHippocampus
Volume27
Issue number10
DOIs
Publication statusPublished - Oct 2017

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Keywords

  • GABAergic inhibition
  • dentate gyrus
  • dentate gyrus - CA3 interface
  • disynaptic inhibition
  • mossy fiber terminals
  • stratum lucidum

ASJC Scopus subject areas

  • Cognitive Neuroscience

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