Meeting Abstract
Although the social functions of most major neurochemical systems have been explored, there are still some major standouts, including the study of vasoactive intestinal polypeptide (VIP). VIP is perhaps best known as a major regulator of prolactin secretion from the pituitary in vertebrates and as a modulator of circadian, reproductive and seasonal rhythms. However, VIP and its cognate VPAC receptors are found in virtually every brain area that is important for social behavior, including all nodes of the core “social behavior network,” suggesting that VIP may have widespread effects on behavior that have been heretofore unknown. We have studied this peptide extensively over the last few years, both in socially diverse species of estrildid finches that breed opportunistically and in socially diverse species of emberizid sparrows that are strongly seasonal in terms of their behavior and physiology. Through a combination of comparative and mechanistic approaches to behavior, we have found that 1) VIP fiber densities and VIP receptor binding correlate with both species and seasonal differences in flocking behavior in a brain-site specific manner; 2) VIP cells show network-wide increased transcriptional activity in response to nest building, including within brain areas identified as important for other affiliative behaviors; and 3) signaling through VPAC receptors modulates social contact, gregariousness, pair-bonding and nesting behavior. Thus, based on our findings from central VPAC receptor antagonism, immediate early gene expression studies, and comparisons of VIP circuitry in territorial and flocking species of finches and sparrows, we propose that VIP is a widespread modulator of affiliation in birds.
