The Role of Direct and Indirect Neurogenesis in Cerebral Cortex Formation

2023 Fiscal Year Final Research Report

• Project/Area Number: 20K06891
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 46020:Anatomy and histopathology of nervous system-related
• Research Institution: Tokyo Metropolitan Institute of Medical Science (2022-2023); Osaka University (2020)
• Principal Investigator: HATANAKA Yumiko 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 (40271548)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 発生・形態形成 / 大脳皮質 / 神経幹細胞 / ニューロン産生 / ニューロンタイプ / Neurogenin-2 / MADM

Outline of Final Research Achievements

Traditionally, cortical neurons were thought to be generated directly from radial glial cells to form cortical layers in an inside-out fashion. However, the discovery of indirect neurogenesis via intermediate neuronal progenitors (INPs) has challenged this view. This study investigated the role of both types of neurogenesis in cortical formation. We found that indirect neurogenesis occurs predominantly during the production of deep layer neurons and generates neuron types that are slightly younger than those generated by direct neurogenesis. Despite the differences in time, both types of neurogenesis produce neurons with similar temporal sequences. In addition, each INP produced pairs of neurons with similar phenotypes. Thus, it appears that indirect neurogenesis works in concert with direct neurogenesis to ensure neuronal diversity and to regulate the number of neurons in the cerebral cortex.

Free Research Field

神経発生

Academic Significance and Societal Importance of the Research Achievements

本研究では、間接分化がどのように大脳皮質形成に関与するかを明らかにした。具体的には、間接分化が直接分化と同じ時間軸でニューロンを生み出し、ニューロンの数を倍加させていることを示した。これらは、ニューロンの生成過程や脳の複雑さの増大を考える上で基盤となる新たな生物学的知見であり、大脳皮質の発達や進化を考える上で重要な学術的意義を持つ。