The brain mechanisms regulated righty and lefty in a scale-eating fish

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K14934
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Neurophysiology / General neuroscience
• Research Institution: University of Toyama
• Principal Investigator: Takeuchi Yuichi 富山大学, 学術研究部医学系, 助教 (40508884)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 左右性 / 脳の左右差 / 学習 / 捕食行動 / 遺伝子発現

Outline of Final Research Achievements

We investigated the neural elements, developmental processes, and genetic basis for laterality in the scale-eating fish, Perissodus microlepis, of Lake Tanganyika. Aiming at whether there is a laterality in scale-eating behavior (i.e., attack side preference) for the first time after birth, a predation experiment was carried out using naive juveniles raised only on artificial feed. The attack side preference of the first day of scale-eating was relatively weak but the strengthened by repeated predation. That is, this behavioral laterality is acquired based on the scale-eating experience. In addition, the brain genes related to the difference between lefty and righty fish and the two hemispheres were analyzed by RNA-seq. We identified a gene that is characteristic of the right or left hemisphere. Among them, genes involved in left-right axis determination in the early embryo were included, suggesting that they are involved in the maintenance of left-right difference in the adult brain.

Free Research Field

神経行動学

Academic Significance and Societal Importance of the Research Achievements

利き手のように体の片方を主に使う行動様式は脳内でどのように制御されるのか？左右の脳は高度に機能分化しており、その機構解明は脳科学上の重要な課題の一つである。私はタンガニイカ湖の鱗食魚を用いて、捕食時にみられる襲撃方向の利きは経験依存的な学習によって確立されるが、運動能力の左右差は生まれつき決まっていることを突き止めた。ヒトの利き手を代表として、様々な動物に広く認められるが、実はその獲得機構は、ほとんど明らかになっていなかった。鱗食魚の利きは非常に明瞭で、それを制御する入力から出力までの神経回路が想定できる。今後は、いまだ謎に包まれた「利きの脳内制御機構」の全容が解明できると考えている。