Mechanisms of reduced hippocampal theta power in in socially defeated rats

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K07491
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52030:Psychiatry-related
• Research Institution: Tokyo Metropolitan Institute of Medical Science
• Principal Investigator: TATEBAYASHI Yoshitaka 公益財団法人東京都医学総合研究所, 脳・神経科学研究分野, 研究員 (80342814)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: うつ病 / 社会敗北ストレス / 海馬 / シータ波 / 前脳基底核内側中隔核 / ミエリン

Outline of Final Research Achievements

The hippocampal theta wave is one of the most important fundamental rhythms of the brain, and a decrease in hippocampal theta power may be positioned at the very upstream cause of depression onset. In socially defeated stress rats, depression-like behavior correlates with hippocampal theta power. In this study, we investigated changes in fatty acids in the brains of socially defeated stress rats and found that abnormalities in fatty acid fractions, similar to those observed in postmortem human brain studies, were present from an early stage. These fraction abnormalities are thought to be due to abnormalities in myelin. Although not directly, the reduction in hippocampal REM theta power is also suspected to be caused by conduction abnormalities in axons due to myelin abnormalities. Further research is needed.

Free Research Field

精神医学

Academic Significance and Societal Importance of the Research Achievements

脳で一番多い構成成分は水分を除くと脂質になる。しかしながら脂質と脳機能の関連はほとんど研究されていない。我々のプレリミナリーな研究によると遺伝子は脂質代謝の一部しか関与しておらず、脂質代謝がどのようにコントロールされているのかは未だに不明である。我々はヒト死後脳研究で、精神疾患のクレペリン診断依存的に脂質異常があることを報告してきた。今回、我々はn数は少ないものの、うつ病モデル動物の脳内で、同様の変化が生じているプレリミナリーなデータを得た。神経軸索におけるミエリン減少は確実に海馬θパワーの低下などに関与すると考えられる。今後の研究の積み重ねが期待される。