Effects of sensory inputs during development on mental behavior after growth

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06909
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 46030:Function of nervous system-related
• Research Institution: University of Fukui
• Principal Investigator: Nishizumi Hirofumi 福井大学, 学術研究院医学系部門, 准教授 (30292832)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 嗅覚 / 刷り込み / 神経回路 / 臨界期

Outline of Final Research Achievements

During development, there is a narrow time window that allows plastic but irreversible changes in neural circuits by environmental inputs. We study the olfactory imprinting during the critical period in mice. Sema7A that induces post-synaptic events within glomeruli is key to imprinting the olfactory memory. When the newborn is exposed to a particular odorant, Sema7A expression is enhanced in the responding glomeruli recruiting dendrites of mitral/tufted cells. This early odor exposure establishes the imprinting that induces attractive responses even toward aversive odorants. The attractive quality is not added to imprinted memory in the oxytocin knockout mice. Blockage of Sema7A signaling in neonates also causes impairment of social interactions in adults. Our study demonstrates that Sema7A signaling and oxytocin are required for imprinting the attractive odor memory during the critical period.

Free Research Field

分子生物学

Academic Significance and Societal Importance of the Research Achievements

カモの雛が最初に見た動くものを親と記憶し後追いする刷り込み現象は、百年以上前にローレンツ博士らが報告したが、その仕組みは未だほとんど解明されていなかった。本研究では、マウス嗅覚系を用いて、新生仔期に匂い刷り込みが成立することを、分子・神経回路・行動レベルで明らかにした。逆に、臨界期に感覚入力が阻害されると、成長後の社会行動に異常が生じることも発見した。以上の研究成果は、感覚入力の阻害や異常入力によって生じる自閉症や愛着障害などヒトの精神発達疾患の、理解や治療法の開発にも繋がることが期待される。