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Telencephalic regulation of the HPA axis in birds

Lookup NU author(s): Dr Tom SmuldersORCiD



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


The hypothalamo-pituitary-adrenal (HPA) axis is one of the major output systems of the vertebrate stressresponse. It controls the release of cortisol or corticosterone from the adrenal gland. These hormones regulate arange of processes throughout the brain and body, with the main function of mobilizing energy reserves toimprove coping with a stressful situation. This axis is regulated in response to both physical (e.g., osmotic) andpsychological (e.g., social) stressors. In mammals, the telencephalon plays an important role in the regulation ofthe HPA axis response in particular to psychological stressors, with the amygdala and part of prefrontal cortexstimulating the stress response, and the hippocampus and another part of prefrontal cortex inhibiting theresponse to return it to baseline. Birds also mount HPA axis responses to psychological stressors, but much less isknown about the telencephalic areas that control this response. This review summarizes which telencephalicareas in birds are connected to the HPA axis and are known to respond to stressful situations. The conclusion isthat the telencephalic control of the HPA axis is probably an ancient system that dates from before the splitbetween sauropsid and synapsid reptiles, but more research is needed into the functional relationships betweenthe brain areas reviewed in birds if we want to understand the level of this conservation.

Publication metadata

Author(s): Smulders TV

Publication type: Review

Publication status: Published

Journal: Neurobiology of Stress

Year: 2021

Volume: 15

Print publication date: 01/11/2021

Online publication date: 10/06/2021

Acceptance date: 03/06/2021

ISSN (electronic): 2352-2895


DOI: 10.1016/j.ynstr.2021.100351