Systematic functional mapping of synaptic connections between cerebral cortical areas

2014 Fiscal Year Final Research Report

• Project/Area Number: 23300148
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Fusional basic brain science
• Research Institution: National Institute for Basic Biology
• Principal Investigator: MATSUZAKI Masanori 基礎生物学研究所, 光脳回路研究部門, 教授 (50353438)
• Co-Investigator(Kenkyū-buntansha): OKADA Takashi 日本医科大学, 大学院医学研究科, 教授 (00326828)
• Project Period (FY): 2011-04-01 – 2015-03-31
• Keywords: 脳・神経 / 高性能レーザー / 運動野 / 大脳皮質

Outline of Final Research Achievements

We used an in vivo Channelrhodopsin-2 (ChR2) photostimulation method to systematically trace the functional connections between the mouse rostral forelimb area (RFA) and the caudal forelimb area (CFA). Simultaneous electrical recordings were utilized to detect spiking activities induced by synaptic inputs originating from photostimulated areas. This method, in combination with anatomical tracing, demonstrated that the RFA receives strong functional projections from layer 2/3 and/or layer 5a, but not from layer 5b, of the CFA. Further, the CFA receives strong projections from layer 5b neurons of the RFA. Next, we investigated complex movements induced by long-duration ChR2 photostimulation over a broad cortical area of awake mice. Many complex movements including forepaw-to-mouth and locomotion-like movements were mapped in several functional modules in the cerebral cortex. In addition, we developed a method of two-photon calcium imaging in a broad cortical area.

Free Research Field

神経科学