The role of noradorenaline in the human motor system

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K17916
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 59030:Physical education, and physical and health education-related
• Research Institution: National Institute of Information and Communications Technology
• Principal Investigator: Yokoi Atsushi 国立研究開発法人情報通信研究機構, 未来ICT研究所脳情報通信融合研究センター, 研究員 (70795393)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 運動学習 / 到達運動 / 力場学習 / 瞳孔径 / ノルアドレナリン

Outline of Final Research Achievements

Noradrenaline (NA) is known for its effect on declarative memory. Interestingly, while the brain’s motor structures (motor cortices and cerebellum) are also under the influence of NA, little is known about whether/how NA affects motor learning. Using pupil diameter, a non-invasive proxy for central NA activity, we investigated how pupil-linked arousal/NA changes while human participants adapt their arm movements to novel dynamic environments. We found that (a) phasic pupil dilation reflects the sensory prediction error and how surprising the error is, and (b) baseline pupil diameter reflects subjective uncertainty (or novelty) about the environment. We also found (c) an inverted-U relationship between pupil-linked arousal/NA and trial-by-trial motor learning rate, indicating that too high/low NA level deteriorates motor learning.

Free Research Field

身体教育科学

Academic Significance and Societal Importance of the Research Achievements

気分・ストレス・覚醒度などは、運動パフォーマンスやトレーニング効果に影響を与えると経験的に考えられているが、その具体的な機序は明らかになっていない。ノルアドレナリン（NA）は、これらの要素と関連の深い神経伝達物質であるが、NAが運動系における情報処理に与える影響は、これまで研究がなされてこなかった。本研究は、上肢を用いた運動学習におけるNAの役割の一端を明らかにしたという点で、学術的意義のみならず応用的な面でも意義を有すると考えられる。