Evaluating the Actions of Others: Neural Mechanisms of Mate Choice in Female Songbirds

Many cherished human activities such as music appreciation or searching for a suitable mate rely on evaluating the actions of others. While much work has focused on how the brain encodes one's own behavior, little is known about how neural circuits evaluate others' actions for proper social responses. A prime example of social assessment is mate choice, in which animals evaluate the quality of potential mates. Birdsong is one of the most quantifiable and tractable signals males use to court females, making the female songbird an ideal system to study mate choice. The zebra finch has emerged as an excellent model in neuroscience for two main reasons: (1) zebra finch song is a highly stereotyped, naturally learned motor sequence and (2) the zebra finch brain contains a highly tractable song system dedicated to singing. While only males sing, females nevertheless have a similar 'song system' which is required for perceiving male song in some songbird species. Thus, my overarching hypothesis is that the song system has co-evolved for complementary sexually dimorphic traits: song production in males and song evaluation in females. Female zebra finches prefer stereotyped (less variable) songs, and this preference depends on early auditory experience. However, evaluating song stereotypy is not a trivial task, as the brain must first form an internal representation of the suitor's song and then rapidly compare features across renditions. I have developed novel neural recording, behavioral, and computational methods to examine how the female song system, as well as interconnected auditory areas, encodes and assesses song stereotypy. I will next investigate how early social experiences, such as listening to her father's song, influence a female's preference, shedding light on the innate vs. learned neural computations underlying social evaluation. Reflecting a larger bias toward males in neuroscience, songbird research has also focused on song production in males, leaving the female brain largely neglected. I propose to meld neuroethology, evolution, and computation to establish the female songbird as a new mechanistic model for how brain circuits evaluate social information. Furthermore, since the song system is analogous to evolutionarily conserved circuits in humans, my findings are likely to have broader implications for human behavior and can provide insights into disorders characterized by deficits in social interactions such as Autism.