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GABAergic inhibition gates excitatory LTP in perirhinal cortex
Author(s) -
Kotak Vibhakar C.,
Mirallave Ana,
Mowery Todd M.,
Sanes Dan H.
Publication year - 2017
Publication title -
hippocampus
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.767
H-Index - 155
eISSN - 1098-1063
pISSN - 1050-9631
DOI - 10.1002/hipo.22799
Subject(s) - long term potentiation , neuroscience , excitatory postsynaptic potential , inhibitory postsynaptic potential , gabaergic , bicuculline , neurotransmission , ltp induction , chemistry , perirhinal cortex , gabaa receptor , biology , receptor , epilepsy , temporal lobe , biochemistry
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 GABA B receptor‐mediated component, we added a GABA B receptor antagonist. When both GABA A and GABA B 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.