2021 Fiscal Year Final Research Report

Specification of brain regions involved in the neurodevelopmental disorders with the maternal separation model

Research Project

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Project/Area Number	19K08348
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 52050:Embryonic medicine and pediatrics-related
Research Institution	Kagawa University
Principal Investigator	Ohta Ken-ichi 香川大学, 医学部, 助教 (50403720)
Co-Investigator(Kenkyū-buntansha)	三木崇範香川大学, 医学部, 教授 (30274294) 鈴木辰吾香川大学, 医学部, 准教授 (50451430) 中村信嗣香川大学, 医学部附属病院, 助教 (30437686) 割田克彦鳥取大学, 農学部, 准教授 (40452669) 日下隆香川大学, 医学部, 教授 (50274288)
Project Period (FY)	2019-04-01 – 2022-03-31
Keywords	母子分離 / 幼少期ストレス / 育児放棄 / 攻撃性 / 暴力性 / 扁桃体
Outline of Final Research Achievements	Child abuse and neglect are believed to lead to delinquency and crime in the future, but it is difficult to elucidate the mechanism in human studies because of the complex involvement of various environmental factors during the developmental process. In this study, we used rat pups separated from their mothers during the early postnatal period as a neglect model and assessed their aggression after maturation and the brain regions responsible for abnormal aggressive behaviors. Our results showed that maternal separation increased aggressive behaviors, which were caused by excess activation in the central amygdala. Given that the central amygdala has been reported to be involved in more violent aggression, our results suggest that a transient stressful environment during childhood can lead to sustained disturbance of the central amygdala, leading to violent delinquency and crime in the future.
Free Research Field	発達神経科学
Academic Significance and Societal Importance of the Research Achievements	本研究ではヒトの脳発達段階で約3歳頃までの一過性の幼少期ストレスが青年期以降の暴力的な攻撃性に繋がる可能性が見出された。更にその原因は普通の攻撃性回路と異なる強い暴力性に関わる扁桃体中心核にあることも示され、実際に同部位の活性化は無抵抗な同種ラットにまで攻撃を加える非常に強い攻撃性を見せることも確認されている。本研究のように原因となる脳部位とその機能が明らかになることは非侵襲的な画像診断法（fNIRS, fMRI）に応用する事ができ、幼少期に強い攻撃傾向が見られた際に単に正常発達過程の一部なのか、それとも将来の非行・犯罪に繋がりやすい兆候なのかをより確実に診断する手法の確立に繋がる意義がある。