A New Humboldt Fellow Brings Fresh Eyes to the Science of Light

Taisuke Eto investigates individual differences in light sensitivity
 

• Taisuke Eto has joined the lab of Manuel Spitschan at the Max Planck Institute for Biological Cybernetics as a two-year Humboldt Fellow.
• His research asks what determines individual differences in light sensitivity.
• The findings could help personalize light therapy for conditions such as circadian rhythm sleep disorders and seasonal affective disorder.

Since March 2026, the Max Planck Institute for Biological Cybernetics has a new face in its halls: Taisuke Eto, who has joined the institute as a postdoctoral fellow under the prestigious Alexander von Humboldt Foundation's fellowship program for postdocs. He will spend the next two years here in Tübingen with the research group Translational Sensory and Circadian Neuroscience led by Manuel Spitschan.
Eto's path to circadian research was not linear: During his master's degree, he studied optics, focusing specifically on optical memory. But after graduating, he chose to shift his focus to research with a more direct connection to humans. “Circadian light sensitivity felt like the natural bridge,” he explained. “It connects the physics of light with how it shapes our biology and daily lives.” Eto pursued this topic for his PhD at Kyushu University, completed five years ago under the supervision of Shigekazu Higuchi, before going on to a postdoctoral position at the National Center of Neurology and Psychiatry in Tokyo.

Towards personalized light therapy

At the Max Planck Institute for Biological Cybernetics, Eto will investigate what determines individual differences in light sensitivity. Light sensitivity is not fixed; it changes with age, sex, and other biological factors. But the range of individual variation goes beyond these patterns. For example, some people need very dim environments to fall asleep, while others are less affected by nighttime light. Understanding what drives these differences is at the heart of his research program.

The implications reach beyond basic science. Light therapy, the controlled use of bright light, is an established treatment for seasonal affective disorder, circadian rhythm sleep disorders, and other sleep-related conditions. Yet it is currently applied in a largely one-size-fits-all manner. “If we know more about how people respond differently to light, we can start to tailor therapies to the individual,” says Eto. "That means more effective treatment for mood and sleep disorders, but also designing a light environment in everyday life that supports a person's health.”

A fresh start in Tübingen

For his research, Eto could hardly have found a better home than the Translational Sensory and Circadian Neuroscience lab: “Manuel Spitschan’s work is known throughout the community,” he said. “Being able to join his team and to learn from the people around him is a real opportunity.”

Outside the lab, Eto is settling into life in Tübingen, and the town seems to suit him well. For someone who has spent his entire life in Japan, the move represents a significant leap, but he has taken to it with enthusiasm. For a keen hiker like him, the Swabian Jura on the doorstep is a welcome bonus, and he is equally looking forward to exploring the local beer culture. He has come with his wife and two children, and they, too, are finding their footing. It is, by all accounts, a promising start—in the lab and beyond.