Lookup NU author(s): Pradeep Dheerendra,
Professor Mark Cunningham,
Dr Tom Smulders
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.
Author(s): Dheerendra P, Lynch NM, Crutwell J, Cunningham MO, Smulders TV
Publication type: Article
Journal: European Journal of Neuroscience
Issue: ePub ahead of Print
Online publication date: 09/11/2017
Acceptance date: 02/11/2017
ISSN (print): 0953-816X
ISSN (electronic): 1460-9568
Publisher: Wiley-Blackwell Publishing Ltd.
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