Our lab is interested in understanding the genetic basis of complex behaviors or brain functions, such as learning and memory, sleep and mood. In order to elucidate fundamental mechanisms underlying the control of these behaviors, we take advantage of the power of the Drosophila (fruit fly) genetics, and study the relationship between genes and behavior at the molecular, cellular, systems and whole animal levels. Currently, our main research projects are on 1) the role of steroid hormones in the regulation of sleep and memory, and 2) the neurological pathways that are affected by the mood stabilizing drug lithium that is used for bipolar disorder. By examining the behavior of well-defined Drosophila mutants and transformants, we study the function of particular genes and their genetic interactions in fundamental aspects of behavior. Molecular and anatomical analyses are also being carried out to reveal the mechanisms employed by particular genes in the regulation of behavior. Our recent findings include 1) the insect molting hormone ecdysteroid promotes sleep and regulates long-term memory in adult flies, and 2) the Ca 2+/CaM-dependent phosphatase calcineurin is involved in the lithium’s action in the nervous system and a novel SLC6 transporter plays a critical role in resistance to lithium toxicity. Our basic research is expected to provide new insights into the evolutionarily conserved mechanisms underlying higher-order brain functions that control complex behavior.