To elucidate the brain functions, it is essential not only to conduct micro-level research such as the conduction of electrical signals and chemical transmission by neurotransmitters, but also the system-level research on how they “function as a circuit” and “connect to actual thoughts and actions.” The Department of Physiology 2 grapples with this arduous but interesting problem by utilizing primates whose brain structure is similar to that of humans, by electrophysiological and pharmacological approaches. The current main theme is the elucidation of mechanisms by which emotion, memory, and attention change the decision-making process and actions. We dream of discovering the universal principle of calculation processing in the brain.

Our laboratory investigates regulatory mechanisms of immune-cell trafficking (adhesion and migration). Adhesion molecules integrins play important roles in lymphocyte homing to peripheral lymphoid organs and leukocyte migration through the inflamed endothelium, and adhesive interactions to antigen-presenting cells. We identified small GTPase Rap1 as a crucial regulator of integrin-dependent cell attachment and migration during these processes. We further clarified the Rap1 signaling pathway to integrins, which abnormal regulation led to a breakdown of self-tolerance due to impaired thymocyte selections and regulatory T cells development and functions. Combined with mice models of immune diseases, we are developing various tissue imaging methods and pursuing therapeutic strategies of intractable immune diseases by controlling immune cell adhesion.