Genome–brain–behavior interdependencies as a framework to understand hormone effects on learned behavior

•Hormones and the genome are functionally interconnected.•Hormones have profound effects on behavior such as learned song in zebra finches.•Genome–brain–behavior connections often considered in evolutionary time occur within a lifespan.•These connections are a conceptual framework to investigate how hormones affect learned behavior.

Hormones have profound effects on the maturation and function of the zebra finch song system. Hormones often signal through receptors that directly or indirectly regulate transcription. In this way, hormones and the genome are functionally connected. Genome–brain–behavior interdependencies are often studied on evolutionary timescales but we can now apply and test these relationships on short timescales, relevant to an individual. Here, we begin to place patterns of hormone-related gene expression into the timeframe of an individual’s lifespan to consider how hormones contribute to organization of neural systems necessary for learned behavior, and how they might signal during experience in ways that affect future behavior. This framework illustrates both how much investigations into genome and hormone function are intertwined, and how much we still need to learn.