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Lookup NU author(s): Dr Tom Smulders
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (CC BY-NC 4.0).
Though widely studied for its function in memory and navigation, the hippocampal formation in mammals also plays an important role in regulating the stress response. If this is an ancestral feature of the hippocampus, then it is likely that the avian hippocampal formation (HF) plays a similar role. Indeed, the avian HF strongly expresses both mineralocorticoid and glucocorticoid receptors, and has indirect projections to the paraventricular nucleus of the hypothalamus, which controls the hypothalamic-pituitary-adrenal (HPA) axis. Hippocampal lesions increase HPA activity, while electrical stimulation suppresses it. In addition, adult hippocampal neurogenesis in birds is reduced in response to different acute and chronic stressors, as it is in mammals. Because the mammalian hippocampus is functionally specialized along its septo-temporal axis, with the temporal pole playing a more important role in the stress response, the hypothesis is put forward that a similar functional specialization exists in birds along the rostro-caudal hippocampal axis. Some, though not all, of the evidence supports a rostro-caudal functional gradient. The evidence for whether this is equivalent to the mammalian septo-temporal organization is currently ambiguous at best, and needs to be more extensively investigated.
Author(s): Smulders TV
Publication type: Review
Publication status: Published
Journal: Brain Behavior and Evolution
Online publication date: 04/09/2017
Acceptance date: 22/05/2015
ISSN (print): 0006-8977
ISSN (electronic): 1421-9743