Neural mechanisms underlying habitual memory formation in insect microbrains

2021 Fiscal Year Final Research Report

• Project/Area Number: 19H03261
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 44050:Animal physiological chemistry, physiology and behavioral biology-related
• Research Institution: Hokkaido University
• Principal Investigator: Mizunami Makoto 北海道大学, 理学研究院, 教授 (30174030)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 学習 / 昆虫 / 報酬 / オクトパミン / コオロギ / 報酬価値引き下げ / 行動の自動遂行 / パブロフ型条件付け

Outline of Final Research Achievements

In Pavlovian conditioning in crickets, a conditioned response (CR) to a conditioned stimulus (CS) is sensitive to devaluation of the unconditioned stimulus (US) early in training but it becomes insensitive to current value of US after extended training. Similar effect of extended training, called “habit formation”, has been found in instrumental conditioning in mammals, but not in Pavlovian conditioning in any animals. In this study I showed that the nature of memory after extended Pavlovian training in crickets fundamentally differs from that in instrumental conditioning in mammals concerning context specificity and effect of extinction trials. Moreover, I established taste aversion learning procedure that is useful for the study of the habit formation and developed methods to monitor activities of octopamine neurons that I have shown to play critical roles in habit formation.

Free Research Field

神経生物学

Academic Significance and Societal Importance of the Research Achievements

本研究は私がコオロギを用いて発見したパブロフ型条件付けのにおける習慣形成について、その性質が従来調べられてきた哺乳類のオペラント学習における習慣形成とは非常に異なる性質を持つことを初めて明らかにしたものであり、動物の学習系の理解に大きく貢献するものであり、ヒトの学習訓練で起こる習慣形成の理解についても新たな洞察を与えた。昆虫の学習系に哺乳類の学習系にも勝るとも劣らない精妙な仕組みがあることを解明した本研究は、社会的にも大きなインパクトが予想される。