Investigating the Mechanism of Fluctuations in Arousal Levels

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K19639
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Research Field: Brain sciences and related fields
• Research Institution: University of Tsukuba
• Principal Investigator: Abe Takashi 筑波大学, 国際統合睡眠医科学研究機構, 准教授 (00549644)
• Project Period (FY): 2017-06-30 – 2023-03-31
• Keywords: 睡眠 / 覚醒 / 精神運動ヴィジランス課題 / 眠気 / 脳波 / Binaural Beats

Outline of Final Research Achievements

We discovered that the fluctuations in arousal (reaction speed), as evaluated by the Psychomotor Vigilance Task, are not random phenomena. Instead, they exhibit long-term temporal correlations. When examining arousal indicators on EEG, we observed that sleep restriction led to an increase in theta band EEG activity, fluctuating within a cycle of 0.03-0.2 Hz, and alpha band EEG activity cycling between 0.004-0.2 Hz. We then tested the hypothesis that auditory stimulation within the frequency band of slow oscillations, under 1 Hz, could trigger arousal fluctuations, thereby promoting sleep onset. Our findings revealed that binaural beats at a frequency of 0.25 Hz effectively facilitated sleep initiation.

Free Research Field

睡眠科学

Academic Significance and Societal Importance of the Research Achievements

本研究は、睡眠制限によって低周波数(<0.2 Hz)の覚醒度のゆらぎが増大することや、低周波数(0.25 Hz)の音刺激によって入眠が促進されることを発見した。これらの機序の解明を進めることによって、覚醒度に関する新規モデルに発展することが期待される。また、低周波数の音刺激による睡眠誘導法の効果を向上することによって、不眠解消という社会的意義にもつながる。