Organisms have a 24-hour cycle rhythm such as sleep and awakening, and hormone secretion.This is due to the biological clock called circadian rhythm that almost all living things on the earth have.In recent years, it has been found that abnormalities in the body clock strongly affect emotions (mood and emotional states), as seen in jet lag and irregular life in the case of humans. The mechanism was previously unknown.

　This time, the research group conducted a test (anxiety-like behavior test) that can measure anxiety in mice.It was clarified for the first time in the world that anxiety behavior in mice fluctuates dynamically throughout the day, and this fluctuation is produced by a molecule called SCOP present in the amygdala.Furthermore, it was found that when a protein called BMAL1, which is one of the central molecules of the biological clock, is deleted in the dorsal cerebral brain region, the diurnal variation of anxiety disappears and a constant level of anxiety is exhibited throughout the day.It was also found that the diurnal variation in mice disappeared even if SCOP was deleted in the dorsal telencephalon.

　With this discovery, the research group speculates that diurnal fluctuations in anxiety have important implications for animal survival.Organisms need to raise their anxiety levels to dangerous times and lower them to safe times.This time, the mechanism of anxiety control was clarified from the aspect of control by the body clock, which is said to greatly contribute to the scientific understanding of the emotion of anxiety.In addition, he says that he will deepen his understanding of the emotions and abnormalities of modern people living in a light environment that is significantly different from the natural environment from a new perspective.