Elucidating olfactory mechanisms recognizing the smell of death

2023 Fiscal Year Final Research Report

• Project Area: Neural representation of "Death"
• Project/Area Number: 21H05141
• Research Category: Grant-in-Aid for Transformative Research Areas (B)
• Allocation Type: Single-year Grants
• Review Section: Transformative Research Areas, Section (III)
• Research Institution: The University of Tokyo
• Principal Investigator: TAKEUCHI HARUKI 東京大学, 大学院理学系研究科(理学部), 教授 (70548859)
• Project Period (FY): 2021-08-23 – 2024-03-31
• Keywords: 嗅覚 / 回路形成 / 神経活動 / 死 / 防御反応 / グルーネベルグ神経節

Outline of Final Research Achievements

There should be a clear boundary between life and death in individual animals, but the criteria for this judgment involve many philosophical elements, and a definitive conclusion on what constitutes death in an individual has yet to be reached. This study aimed to elucidate how compounds released upon the death of an animal or odors emitted by predators directly associated with death are processed in the brain. The results showed that death-related odors are detected by a specialized sensory organ called the Grueneberg ganglion (GG). This information is then processed not only in the general olfactory cortex but also in a region called the amygdala-piriform transition area (AmPir). Subsequently, the information is transmitted to the amygdala, which controls emotional responses such as fear and anxiety, thereby triggering sustained defensive reactions in the individual.

Free Research Field

分子神経科学

Academic Significance and Societal Importance of the Research Achievements

本研究により、動物にとって生死に関わる匂い物質は、通常の嗅覚器官とは異なる感覚器と脳領域で処理されることが明らかになった。これまでの神経科学では、特定の入力がどのような回路を通じて特定の行動を引き起こすかに関する報告は多いが、特定の入力が状態変化を引き起こし、入力が消失した後も特定の状態を持続させる脳内メカニズムに関する報告はほとんどない。この点で、本研究が発見したAmPirの持続的な神経活動は、特定の状態を維持する神経メカニズムとして新しいモデルであると言える。