Graduate School of Science and Engineering

Graduate School of Pharma-Medical Sciences

Program of Cognitive and Emotional Neuroscience

Program of Applied Natural Medicine

I investigate circadian changes in memory and emotion and their molecular mechanisms in mice. Using behavioral, biochemical, molecular biological, and genetic methods, I systematically elucidate memory and emotion's molecular and physiological functions through multi-level experiments from molecular to behavioral analysis.

Circadian clocks control long-term recognition memory formation in a circadian manner. Disruption of the central clock (hypothalamic suprachiasmatic nucleus) or the hippocampal clock (loss of clock molecules in the hippocampus) lose circadian change in long-term memory. Circadian variation in the amount of SCOP in the hippocampal lipid rafts regulates the K-Ras-ERK/MAPK-CREB pathway. It produces diurnal rhythm in long-term memory performance (Nat. Commun. 7, 12926, 2016). Anxiety-like behavior in mice also has a circadian rhythm. It is controlled by the circadian clock and SCOP in the amygdala (Sci. Rep. 6, 33500, 2016).

Novel neurosteroids, 7α-hydroxypregnenolone and 7α-hydroxydehydroepiandrosterone, are synthesized in the mouse brain after spatial learning. These steroids contribute to remote memory via remodeling dendritic spines in hippocampal neurons (iScience 23, 101559, 2020).