Exploration of a new pathway of light transmission to the deep brain

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K21416
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
• Research Institution: The University of Tokyo
• Principal Investigator: Nagata Takashi 東京大学, 物性研究所, 助教 (90589962)
• Project Period (FY): 2020-07-30 – 2023-03-31
• Keywords: 光受容 / 脳深部

Outline of Final Research Achievements

Many vertebrates, including mammals, express the photosensitive protein opsins in the deep brain regions, suggesting that "brain photoreception" by cells with light-sensing functions takes place. However, it has been questioned whether light can reach the deep brain, especially in mammals, because light from the surface of the head is reflected, absorbed, and scattered by hair, skin, skull, and brain tissue. In this research project, the possibility was examined that light is transmitted to the deep brain by a pathway through the eyes. An experimental system that can measure light intensity and spectrum in deep brain regions was newly constructed and light intensity was measured at a deep brain region when light was incident from the eyes of mice. The results showed that light was more efficiently transmitted to the deep brain via the eyes than through the skin and cranium.

Free Research Field

光生物学

Academic Significance and Societal Importance of the Research Achievements

近年の研究により、マウスなどにおいて脳深部に発現するオプシンが光依存的に体温の調節や体の活動レベルの制御に関わっていることが明らかになりつつある。本研究により脳深部への効率的な光経路の候補が明らかになったことで、光が動物の生理機能に与える影響を理解するために、脳内での光受容の研究が更に重要になると考えられる。またヒトの脳も光に応答して様々な生理的変化を引き起こすことが既に知られており、将来的にヒトにおいても同じ光経路が明らかになれば、医学的な観点からも大きな波及効果につながる可能性がある。