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In vitro characterization of gamma oscillations in the hippocampal formation of the domestic chick

Lookup NU author(s): Dr Pradeep Dheerendra, Joseph Crutwell, Professor Mark Cunningham, Dr Tom SmuldersORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Avian and mammalian brains have evolved independently from each other for about 300 million years. During that time, the hippocampal formation (HF) has diverged in morphology and cyto-architecture, but seems to have conserved much of its function. It is therefore an open question how seemingly different neural organizations can generate the same function. A prominent feature of the mammalian hippocampus is that it generates different neural oscillations, including the gamma rhythm, which plays an important role in memory processing. In this study, we investigate whether the avian hippocampus also generates gamma oscillations, and whether similar pharmacological mechanisms are involved in this function. We investigated the existence of gamma oscillations in avian HF using in vitro electrophysiology in P0-P12 domestic chick (Gallus gallus domesticus) HF brain slices. Persistent gamma frequency oscillations were induced by the bath application of the cholinergic agonist carbachol, but not by kainate, a glutamate receptor agonist. Similar to other species, carbachol-evoked gamma oscillations were sensitive to GABAA, AMPA/kainate, and muscarinic (M1) receptor antagonism. Therefore, similar to mammalian species, muscarinic receptor-activated avian HF gamma oscillations may arise via a pyramidal-interneuron gamma (PING) based mechanism. Gamma oscillations are most prominent in the ventromedial area of the hippocampal slices, and gamma power is reduced more laterally and dorsally in the HF. We conclude that similar micro-circuitry may exist in the avian and mammalian hippocampal formation, and this is likely to relate to the shared function of the two structures.

Publication metadata

Author(s): Dheerendra P, Lynch NM, Crutwell J, Cunningham MO, Smulders TV

Publication type: Article

Publication status: Published

Journal: European Journal of Neuroscience

Year: 2017

Volume: 48

Issue: 8

Pages: 2807-2815

Print publication date: 24/10/2018

Online publication date: 09/11/2017

Acceptance date: 02/11/2017

Date deposited: 20/11/2017

ISSN (print): 0953-816X

ISSN (electronic): 1460-9568

Publisher: Wiley-Blackwell Publishing Ltd


DOI: 10.1111/ejn.13773


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Funder referenceFunder name
102561/Z/13/ZWellcome Trust