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

Dheerendra, P. , Lynch, N. M., Crutwell, J., Cunningham, M. O. and Smulders, T. V. (2018) In vitro characterization of gamma oscillations in the hippocampal formation of the domestic chick. European Journal of Neuroscience, 48(8), pp. 2807-2815. (doi: 10.1111/ejn.13773) (PMID:29120510) (PMCID:PMC6220815)

Abstract

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 cytoarchitecture, 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.

• Item Type: Articles
• Additional Information: PD was supported by the Wellcome Trust PhD studentship program (Grant No: WT102561/Z/13/Z). JC was supported by the Graduate School of the Faculty of Medical Sciences at Newcastle University. TVS was supported by BBSRC Grant number BB/K003534/1. We thank the staff of the Comparative Biology Centre for the excellent animal care.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Dheerendra, Dr Pradeep
• Authors: Dheerendra, P., Lynch, N. M., Crutwell, J., Cunningham, M. O., and Smulders, T. V.
• College/School: College of Medical Veterinary and Life Sciences > School of Psychology & Neuroscience
• Journal Name: European Journal of Neuroscience
• Publisher: Wiley
• ISSN: 0953-816X
• ISSN (Online): 1460-9568
• Published Online: 09 November 2017
• Copyright Holders: Copyright © 2017 The Authors
• First Published: First published in European Journal of Neuroscience 48(8): 2807-2815
• Publisher Policy: Reproduced under a Creative Commons License