Investigation of brain-wide responses evoked by optogenetic activation of the dorsal or ventral hippocampus

2015 Fiscal Year Final Research Report

• Project/Area Number: 25430011
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology / General neuroscience
• Research Institution: Keio University
• Principal Investigator: takata norio 慶應義塾大学, 医学部, 特任講師 (50415212)
• Co-Investigator(Renkei-kenkyūsha): tanaka f. kenji 慶應義塾大学, 医学部, 准教授 (30329700) ; hikishima keigo 公益財団法人実験動物中央研究所, 病理病態研究部, 研究員 (30420219) ; komaki yuji 公益財団法人実験動物中央研究所, 病理病態研究部, 研究員 (10548499)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 光遺伝学 / fMRI / ChR2 / 遺伝子改変マウス / マウス

Outline of Final Research Achievements

The dorsal and ventral hippocampal regions (dHP and vHP) are proposed to have distinct functions. Nevertheless, the extra-hippocampal influences of dHP and vHP activities remain unclear. In this study, we compared the spatial distribution of brain-wide responses upon dHP or vHP activation. To achieve this, we performed optogenetic fMRI using an anesthetized transgenic mouse, whose CA1 pyramidal neurons expressed a step-function opsin variant of channelrhodopsin-2 (ChR2). Activation at the dHP, but not the vHP, evoked BOLD responses at the retrosplenial cortex (RSP), which is in line with anatomical evidence. In contrast, BOLD responses at the lateral septum (LS) were induced only upon vHP activation, even though both dHP and vHP send axonal fibers to the LS. Our findings suggest that the primary targets of dHP and vHP activation are distinct, which concurs with attributed functions of the dHP and RSP in spatial memory, as well as of the vHP and LS in emotional responses.

Free Research Field

総合領域