Data_Sheet_1_Gamma music: a new acoustic stimulus for gamma-frequency auditory steady-state response.ZIP

A frequency range exceeding approximately 30 Hz, denoted as the gamma frequency range, is associated with various cognitive functions, consciousness, sensory integration, short-term memory, working memory, encoding and maintenance of episodic memory, and retrieval processes. In this study, we proposed a new form of gamma stimulation, called gamma music, combining 40 Hz auditory stimuli and music. This gamma music consists of drums, bass, and keyboard sounds, each containing a 40 Hz frequency oscillation. Since 40 Hz stimuli are known to induce an auditory steady-state response (ASSR), we used the 40 Hz power and phase locking index (PLI) as indices of neural activity during sound stimulation. We also recorded subjective ratings of each sound through a questionnaire using a visual analog scale. The gamma music, gamma drums, gamma bass, and gamma keyboard sounds showed significantly higher values in 40 Hz power and PLI compared to the control music without a 40 Hz oscillation. Particularly, the gamma keyboard sound showed a potential to induce strong ASSR, showing high values in these indices. In the subjective ratings, the gamma music, especially the gamma keyboard sound, received more relaxed, comfortable, preferred, pleasant, and natural impressions compared to the control music with conventional gamma stimulation. These results indicate that our proposed gamma music has potential as a new method for inducing ASSR. Particularly, the gamma keyboard sound proved to be an effective acoustic source for inducing a strong ASSR while preserving the comfortable and pleasant sensation of listening to music. Our developed gamma music, characterized by its pleasantness to the human ear, offers a significant advantage for the long-term use of gamma stimulation. The utilization of this music could potentially reduce the physical and psychological burden on participants compared to conventional 40 Hz stimuli. This music is not only expected to contribute to fundamental neuroscience research utilizing ASSR but also to facilitate the implementation of gamma music-based interventions aimed at enhancing human cognitive functions in everyday life.

频率高于约30赫兹的频段被定义为伽马频段（gamma frequency range），其与多种认知功能、意识、感觉整合、短时记忆、工作记忆、情景记忆的编码与维持以及提取过程密切相关。本研究提出了一种新型伽马刺激形式——伽马音乐（gamma music），将40赫兹听觉刺激与音乐相结合。该伽马音乐由鼓、贝斯与键盘音色构成，每种音色均包含40赫兹的频率振荡。由于已知40赫兹刺激可诱发听觉稳态响应（auditory steady-state response, ASSR），本研究采用40赫兹功率与相位锁定指数（phase locking index, PLI）作为声音刺激期间神经活动的评估指标。我们还通过视觉模拟量表（visual analog scale, VAS）问卷记录了受试者对每种声音的主观评分。相较于无40赫兹振荡的对照音乐，伽马音乐、伽马鼓音色、伽马贝斯音色与伽马键盘音色在40赫兹功率与PLI值上均显著更高。其中，伽马键盘音色展现出较强的ASSR诱发潜力，在上述指标中均表现优异。在主观评分中，伽马音乐——尤其是伽马键盘音色——相较于采用传统伽马刺激的对照音乐，获得了更放松、舒适、更受偏好、愉悦且自然的主观评价。上述结果表明，本研究提出的伽马音乐有望成为一种新型ASSR诱发方法。其中，伽马键盘音色被证实为一种有效的声学刺激源，可在保留聆听音乐的舒适愉悦感的同时诱发较强的ASSR。我们开发的伽马音乐以入耳愉悦性为核心特征，为伽马刺激的长期应用提供了显著优势。相较于传统40赫兹刺激，该音乐有望降低受试者的生理与心理负担。该音乐不仅有望为利用ASSR开展的基础神经科学研究提供助力，还可推动基于伽马音乐的干预手段实施，以提升日常生活中的人类认知功能。