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Hippocampus. 2017 Dec;27(12):1217-1223. doi: 10.1002/hipo.22799. Epub 2017 Sep 26.

GABAergic inhibition gates excitatory LTP in perirhinal cortex.

Author information

1
Center for Neural Science, New York, New York 10003.
2
Department of Psychology, Neuroscience Institute, NYU Langone Medical Center, New York University, New York, New York 10003.
3
Department of Biology, Neuroscience Institute, NYU Langone Medical Center, New York University, New York, New York 10003.
4
Neuroscience Institute, NYU Langone Medical Center, New York University, New York, New York 10003.

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.

KEYWORDS:

GABAA receptor; GABAB receptor; LTP; auditory cortex; perirhinal cortex

PMID:
28881444
PMCID:
PMC5745066
DOI:
10.1002/hipo.22799
[Indexed for MEDLINE]
Free PMC Article

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