Role of autonomic nervous system on synchronization between vocal behavior and motor action in infant crying

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H06595
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Experimental psychology
• Research Institution: The University of Tokyo
• Principal Investigator: Shinya Yuta 東京大学, 大学院教育学研究科(教育学部), 特任研究員 (20803828)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 泣き / 乳児 / 自律神経系 / 発声 / 運動 / 心拍変動 / 音響解析

Outline of Final Research Achievements

This study investigated how vocalization and limb-movement would change depending on autonomic nervous activity before and after crying in 3 month-old infants. The results showed that, compared to awake states, the frequency of their vocalization significantly increased during fussy/crying, while the variation of fundamental and formant frequency decreased. For limbs-movements, their limb-movements became more jerky and less coordinated although they increased limb movements. Moreover, the changes of motor and voice were associated with the change of autonomic activity including increased heart rate, decreased heart rate variability, and increased distal-proximal temperature gradient. The co-variation of autonomic nervous system and vocal/motor activity in the early development might be based on the development of emotional expression in language and communication.

Free Research Field

発達科学

Academic Significance and Societal Importance of the Research Achievements

本研究の成果から，乳児の啼泣時には情動中枢の活動亢進により，副交感神経系 (迷走神経) が抑制され，声帯・声道の緊張が高まることで音響特徴が変化する可能性や，皮質の発声・運動中枢が抑制され，随意的な制御が低下する可能性が示唆された。また，本研究が示した自律神経系と発声・運動間の共変動については、言語やコミュニケーションにおける感情表現の基盤になると考えられ，今後それらの発達的理解を深めるための一助となりうる。