Neural circuit mechanism to determine hippocampal brain state

2016 Fiscal Year Final Research Report

• Project/Area Number: 16K14562
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Neurophysiology / General neuroscience
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Hayashi Yasunori 国立研究開発法人理化学研究所, 脳科学総合研究センター, チームリーダー (90466037)
• Project Period (FY): 2016-04-01 – 2017-03-31
• Keywords: セロトニン / 縫線核 / 記憶学習 / 海馬

Outline of Final Research Achievements

We hypothesized that the input from the raphe nucleus to the hippocampus regulates the brain status. We expressed G-CaMP6 in the serotonergic axonal projection from the medial raphe nucleus to the hippocampus and observed it with a two-photon microscope. The mouse walked freely on the trackball and rewarded when it came to a specific place. As a result, we found that there are two types of projection fibers from the raphe nucleus to the hippocampus, one consistent with the reward at the start of walking (that is, the start of the θ wave period). Next, channel rhodopsin was expressed in raphe nucleus serotonin nerve and stimulation was carried out locally in the hippocampus. The walking speed in reward area became slower. We postulated that it strengthen reward information.

Free Research Field

神経科学