Search for neural mechanisms by which memories create time

2017 Fiscal Year Final Research Report

• Project Area: The Science of Mental Time: investigation into the past, present, and future
• Project/Area Number: 25119004
• Research Category: Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area)
• Allocation Type: Single-year Grants
• Review Section: Complex systems
• Research Institution: The University of Tokyo
• Principal Investigator: Ikegaya Yuji 東京大学, 大学院薬学系研究科(薬学部), 教授 (10302613)
• Co-Investigator(Renkei-kenkyūsha): NOMURA Hiroshi 北海道大学, 大学院薬学研究院, 講師 (10549603) ; FUJISAWA Shigeyoshi 理化学研究所, 脳科学総合研究センター, 主任研究員 (20589395)
• Project Period (FY): 2013-06-28 – 2018-03-31
• Keywords: 記憶 / 時間 / 海馬

Outline of Final Research Achievements

Patients with learning deficits due to hippocampal damage cannot recognize "passage of time", indicating that memory is the source of "mind of time". In this study, we explored the mechanism of time compression and the operation of time progression mainly in hippocampal ripple waves and obtained the following two main findings.
(1) When memory engrams are reactivated during the hippocampal ripples, the excitation/inhibition balance of the neural circuit transiently shifts toward excitation. These results were published in Nature Neurosciencee.
(2) Hippocampal ripples down-regulate the excitability of the neural circuit during slow-wave sleep, thereby purifying memory engrams and securing the storage capacity for future memories. These results were published in Science and were also highlighted in a newspaper and other media.

Free Research Field

神経科学