Anatomy of the Chicken Hippocampus: Investigating its Role in Stress Regulation

Abstract

The avian hippocampus, an evolutionarily ancient brain structure, plays a crucial role in both memory and emotional regulation. Its complex internal organization, characterized by diverse subdivisions and a functional longitudinal arrangement, poses a unique challenge in comparative neurobiology. This thesis investigates the role of the avian hippocampus in stress regulation through an integrative approach involving immunohistochemistry, gene expression analysis, and tract-tracing experiments in chickens. Contrary to the mammalian hippocampal functional dichotomy, our study reveals significant activation in the rostral avian hippocampus in response to acute stress, accompanied by intricate activation patterns across the ventral, dorsomedial, and dorsolateral hippocampal subdivisions. These findings suggest a more comprehensive involvement of the hippocampus in stress modulation than previously acknowledged. By advancing our understanding of avian neurobiology and stress mechanisms, this research highlights the need for further research into the anatomical and functional complexity of the avian hippocampus. Moreover, it opens new avenues for investigating the evolutionary conservation of hippocampal functions across vertebrates.