Investigation of mechanisms generating spontaneous activity in the neonatal mouse barrel cortex

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H03346
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 46010:Neuroscience-general-related
• Research Institution: National Institute of Genetics
• Principal Investigator: Iwasato Takuji 国立遺伝学研究所, 遺伝形質研究系, 教授 (00311332)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 神経科学 / 神経回路 / 生後発達 / 自発活動 / 体性感覚系 / マウス

Outline of Final Research Achievements

Spontaneous activity during the early postnatal period is thought to be crucial for the establishment of mature neural circuits. We previously found “patchwork”-type spontaneous activity in the neonatal barrel cortex. In this study, by establishing an ex vivo calcium imaging system, we found that neurons in the whisker-innervating region of the trigeminal ganglion of neonatal mice generate spontaneous activity. A small percentage of neurons showed some obvious correlated activity, and these neurons were mostly located close to one another. Trigeminal ganglion spontaneous activity was majorly exhibited by large diameter neurons, a characteristic of mechanosensory neurons, and was blocked by chelation of extracellular calcium. Moreover, this activity was diminished by the adult stage. Spontaneous activity in the trigeminal ganglion during the first postnatal week could be a source of spontaneous activity observed in the neonatal mouse barrel cortex.

Free Research Field

神経科学

Academic Significance and Societal Importance of the Research Achievements

生後発達初期の脳には外界からの刺激に依存しない「自発的な神経活動」が存在し、神経回路精緻化に重要な役割を担う。近年、発達期特異的な自発活動は広範な脳領域に存在することが明らかになりつつあり、その性質に注目が集まっている。研究代表者らは、新生仔マウス大脳皮質体性感覚野に新規の時空間パターンをもつ自発活動が検出されることを見出していた。本研究は、この自発活動の発生機序を理解することを目的とした。マウス体性感覚野は回路精緻化機構の卓越したモデルであり、本研究の成果は、他のモダリティーでの研究との統合によって、発達期の神経回路精緻化機構の全体像の理解につながることが期待される。