Neuroendocrine Mechanisms Underlying Non-breeding Aggression: Common Strategies Between Birds and Fish

• Published in: Frontiers in neural circuits Vol. 15; p. 716605
• Main Authors: Quintana, Laura, Jalabert, Cecilia, Fokidis, H Bobby, Soma, Kiran K, Zubizarreta, Lucia
• Format: Journal Article
• Language: English
• Published: Switzerland Frontiers Research Foundation 29.07.2021; Frontiers Media S.A
• Subjects: Aggression; Aggression - physiology; Aggression - psychology; Aggressiveness; Animal behavior; Animal models; Animals; Aromatase; Birds; Breeding seasons; Decision making; estradiol; Fishes; Food; Food availability; Food intake; Foraging behavior; Gene expression; Laboratories; Males; Melospiza melodia; Neuro Circuits; Neuroendocrine Cells - metabolism; Neuropeptide Y; Neuropeptides; neurosteroids; Neurosteroids - metabolism; Peptides; Preoptic area; Reptiles & amphibians; Seasons; Social behavior; Social organization; songbird; Territoriality; testosterone; Vertebrates; aromatase; testosterone; neurosteroids; electric fish; songbird; territoriality; estradiol; food intake
• ISSN: 1662-5110; 1662-5110
• DOI: 10.3389/fncir.2021.716605

Aggression is an adaptive behavior that plays an important role in gaining access to limited resources. Aggression may occur uncoupled from reproduction, thus offering a valuable context to further understand its neural and hormonal regulation. This review focuses on the contributions from song sparrows ( ) and the weakly electric banded knifefish ( ). Together, these models offer clues about the underlying mechanisms of non-breeding aggression, especially the potential roles of neuropeptide Y (NPY) and brain-derived estrogens. The orexigenic NPY is well-conserved between birds and teleost fish, increases in response to low food intake, and influences sex steroid synthesis. In non-breeding , NPY increases in the social behavior network, and NPY-Y1 receptor expression is upregulated in response to a territorial challenge. In , NPY is upregulated in the preoptic area of dominant, but not subordinate, individuals. We hypothesize that NPY may signal a seasonal decrease in food availability and promote non-breeding aggression. In both animal models, non-breeding aggression is estrogen-dependent but gonad-independent. In non-breeding , neurosteroid synthesis rapidly increases in response to a territorial challenge. In , brain aromatase is upregulated in dominant but not subordinate fish. In both species, the dramatic decrease in food availability in the non-breeding season may promote non-breeding aggression, via changes in NPY and/or neurosteroid signaling.