Re-paired Bonds: ZENK Expression in Auditory Recognition and Reward Systems of Zebra Finch Partners

Abstract

Pair bonding, central to the survival and reproductive success of many social species, is supported by both the vocal recognition of partner signals and the reward systems that reinforce these attachments. In zebra finches (Taeniopygia guttata), a socially monogamous songbird, pair bonds form rapidly and can be sustained through auditory contact alone, even persisting after temporary re-pairing (Silcox & Evans, 1982). While these behavioral dynamics are well established, the neural mechanisms that support an individual's auditory recognition and valuation of partners remain less understood. To investigate this process, we exposed zebra finches to recordings of calls from current partners, previous partners, or strangers while housed in a dark setting without other stimuli. Brains were fixed afterward, and neural activity was assessed by staining for the immediate early gene, ZENK. ZENK-labeled cells were quantified in auditory processing and social memory regions (Field L subsections, caudomedial mesopallium, caudomedial nidopallium) and dopaminergic regions involved with reward and valuation (nucleus accumbens, ventral tegmental area). Analyses of these regions will focus on how neural activation patterns vary across sex and social treatment, offering insight into how auditory recognition of partner calls and dopaminergic reward responses shape the persistence of monogamous pair bonds in zebra finches.