GABAergic inhibition gates excitatory LTP in perirhinal cortex

Vibhakar C. Kotak, Ana Mirallave, Todd M. Mowery, Dan H. Sanes

Research output: Contribution to journalArticlepeer-review

Abstract

The perirhinal cortex (PRh) is a key region downstream of auditory cortex (ACx) that processes familiarity linked mnemonic signaling. In gerbils, ACx-driven EPSPs recorded in PRh neurons are largely shunted by GABAergic inhibition (Kotak et al., 2015, Frontiers in Neural Circuits, 9). To determine whether inhibitory shunting prevents the induction of excitatory long-term potentiation (e-LTP), we stimulated ACx-recipient PRh in a brain slice preparation using theta burst stimulation (TBS). Under control conditions, without GABA blockers, the majority of PRh neurons exhibited long-term depression. A very low concentration of bicuculline increased EPSP amplitude, but under this condition TBS did not significantly increase e-LTP induction. Since PRh synaptic inhibition included a GABAB receptor-mediated component, we added a GABAB receptor antagonist. When both GABAA and GABAB receptors were blocked, TBS reliably induced e-LTP in a majority of PRh neurons. We conclude that GABAergic transmission is a vital mechanism regulating e-LTP induction in the PRh, and may be associated with auditory learning.

Original languageEnglish (US)
Pages (from-to)1217-1223
Number of pages7
JournalHippocampus
Volume27
Issue number12
DOIs
StatePublished - Dec 2017

Keywords

  • GABAA receptor
  • GABAB receptor
  • LTP
  • auditory cortex
  • perirhinal cortex

ASJC Scopus subject areas

  • Cognitive Neuroscience

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