Rotman Research Institute, Baycrest, 3560 Bathurst St, North York, ON, M6A 2E1, Canada.
Department of Psychology, University of Toronto, Toronto, ON, M5S 1A1, Canada.
Sci Rep. 2021 Nov 19;11(1):22581. doi: 10.1038/s41598-021-02055-y.
Optimal perception requires adaptation to sounds in the environment. Adaptation involves representing the acoustic stimulation history in neural response patterns, for example, by altering response magnitude or latency as sound-level context changes. Neurons in the auditory brainstem of rodents are sensitive to acoustic stimulation history and sound-level context (often referred to as sensitivity to stimulus statistics), but the degree to which the human brainstem exhibits such neural adaptation is unclear. In six electroencephalography experiments with over 125 participants, we demonstrate that the response latency of the human brainstem is sensitive to the history of acoustic stimulation over a few tens of milliseconds. We further show that human brainstem responses adapt to sound-level context in, at least, the last 44 ms, but that neural sensitivity to sound-level context decreases when the time window over which acoustic stimuli need to be integrated becomes wider. Our study thus provides evidence of adaptation to sound-level context in the human brainstem and of the timescale over which sound-level information affects neural responses to sound. The research delivers an important link to studies on neural adaptation in non-human animals.
最佳感知需要适应环境中的声音。适应涉及到在神经反应模式中表示声刺激历史，例如，通过改变响应幅度或潜伏期，因为声音水平的上下文发生变化。啮齿动物的听觉脑干中的神经元对声刺激历史和声音水平的上下文（通常称为对刺激统计信息的敏感性）敏感，但人类脑干表现出这种神经适应的程度尚不清楚。在六个涉及超过 125 名参与者的脑电图实验中，我们证明了人类脑干的反应潜伏期对几十毫秒内的声刺激历史敏感。我们进一步表明，人类脑干反应至少在最后 44 毫秒内适应声音水平的上下文，但当需要整合声刺激的时间窗口变宽时，对声音水平上下文的神经敏感性会降低。因此，我们的研究为人类脑干对声音水平上下文的适应以及声音水平信息影响声音神经反应的时间尺度提供了证据。这项研究为非人类动物的神经适应研究提供了重要的联系。
