Elucidation of neocortical circuits underlying associative learning

2018 Fiscal Year Final Research Report

• Project/Area Number: 16H05927
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Basic / Social brain science
• Research Institution: Nagoya University
• Principal Investigator: Yamashita Takayuki 名古屋大学, 環境医学研究所, 准教授 (40466321)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 大脳皮質 / バレル / 投射ニューロン / 電気生理学

Outline of Final Research Achievements

How animals learn an association between certain sensory stimuli and a reward remains unclear. In this study, we focused on cortico-cortical projection neurons in the primary sensory cortex which is the early branch point of the signal pathway that conveys reward-related sensory stimuli. We revealed that, upon learning, layer 2/3 neurons bi-directionally change their sensitivity to reward-associated sensory stimuli in a projection-specific manner. We further analyzed the anatomical patterns of layer 2/3 projection neurons and revealed that the projection targets of dorsal and ventral pathways are significantly overlapped at this early stage. In addition, our recordings from layer 5 neurons suggested that synaptic computation by layer 5 neurons during active behavior is different from that of layer 2/3 neurons. Thus, our data uncovered the basic properties of cortico-cortical projection neurons of primary sensory cortex.

Free Research Field

神経生理学

Academic Significance and Societal Importance of the Research Achievements

マウス大脳皮質一次体性感覚野をモデルとした本研究により、大脳皮質一次感覚野の第2/3層より皮質内に投射する長距離投射細胞の解剖・生理学的性質の主要部分が明らかになった。本成果は、投射部位の異なる長距離投射細胞は機能的に異なる役割を持つという概念の形成に大きく貢献した。また、本研究の結果から第5層では第2/3層とは異なる計算原理で洞毛運動時の活動パターンが形成されている可能性が示唆され、今後のさらなる研究の発展が期待される。