Behavioral pharmacological analyzes of neurotransmitters and hormones involved in the memory formation of filial imprinting

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K06915
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 46030:Function of nervous system-related
• Research Institution: Teikyo University
• Principal Investigator: Aoki Naoya 帝京大学, 薬学部, 准教授 (50525334)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 刷り込み / アセチルコリン / ムスカリン受容体 / 甲状腺ホルモン

Outline of Final Research Achievements

In filial imprinting, newly-hatched Chicks innately approach a moving object, and memorize it as their parents by repeatedly approaching them. We revealed thyroid hormone in the brain is important for imprinting acquisition. Thyroid hormone levels in the brain rise just before hatching and are further increased by imprinting training. It was not clear how the thyroid hormones contribute to the learning process of the imprinting. In this study, we developed a behavioral apparatus for analyzing the learning process of imprinting by dividing it into three categories “innate approach”, “acquired approach'', and “discrimination”. Then, we examined if the increased thyroid hormone in the just before hatching involved in the learning processes of imprinting. we clarified that the increase of thyroid hormone just before hatching contributes to “acquired approach''

Free Research Field

神経科学

Academic Significance and Societal Importance of the Research Achievements

刷り込みは孵化直後に親に対して愛着を形成する早期学習である。本研究の結果は、発生時の甲状腺ホルモンが孵化直後の愛着形成に必要であることを示唆している。今回用いた抗甲状腺剤であるメチマゾールは、バセドウ病などの甲状腺機能亢進症の治療に用いられている。バセドウ病の妊婦には、より影響が少ない抗甲状腺剤チウラジールが処方されることが多いが、胎児期での甲状腺ホルモンの欠乏の影響はまだ不明な点が多く、本研究の結果は抗甲状腺剤を処方する上で参考になると考える。また、今回行ったニワトリヒナを用いた実験系は甲状腺ホルモンの欠乏が脳発達に与える影響を調べるために有用であると考える。