Functional analysis of the supramammillary nucleus-hippocampal circuits

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K07043
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology / General neuroscience
• Research Institution: Doshisha University (2018-2019); The University of Tokyo (2017)
• Principal Investigator: Hashimotodani Yuki 同志社大学, 研究開発推進機構, 准教授 (50401906)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 海馬 / 乳頭体上核 / 歯状回 / 共放出 / シナプス可塑性 / 光遺伝学 / 神経回路

Outline of Final Research Achievements

The supramammillary nucleus (SuM) of the hypothalamus projects to the dentate gyrus and the CA2 region of the hippocampus. Although the SuM to hippocampus circuits have been implicated in spatial and emotional memory formation, little is known about precise neural connections between the SuM and hippocampus. By using optogenetics and electrophysiology, we found that the SuM neurons project to both granule cells and GABAergic interneurons and co-release glutamate and GABA. We also found that SuM inputs potentiate granule cell firing when temporally associated with perforant path inputs. These results indicate that the SuM modulates dentate gyrus activity by modulating granule cell outputs.

Free Research Field

神経生理学

Academic Significance and Societal Importance of the Research Achievements

乳頭体上核と海馬で形成される神経回路はこれまで記憶や情動に関して重要な役割を果たすことが示唆されてきた。最近はさらに睡眠やナビゲーションにも関わることが報告され、乳頭体上核―海馬間神経回路はより多様な脳機能に寄与することがわかってきた。本研究はこういった重要な脳機能を発揮する神経基盤をシナプスレベルで明らかにした。