Human Psychobiology Laboratory, Experimental Psychology Department, University of Sevilla, Sevilla, Spain.
Department of Developmental and Social Psychology, University of Padova, Via Venezia, Padova, Italy.
Exp Physiol. 2021 Apr;106(4):1072-1098. doi: 10.1113/EP089125. Epub 2021 Mar 10.
What is the central question of this study? Auditory stimulation produces a response in different physiological systems: cardiac, peripheral blood flow, electrodermal, cortical and peripheral haemodynamic responses and auditory event-related potentials. Do all these subsystems covary when responding to auditory stimulation, suggesting a unified locus of control, or do they not covary, suggesting independent loci of control for these physiological responses? What is the main finding and its importance? Auditory sensory gating reached a fixed level of neural activity independently of the intensity of auditory stimulation. The use of multivariate techniques revealed the presence of different regulatory mechanisms for the different physiologically recorded signals.
We studied the effects of an increasing amplitude of auditory stimulation on a variety of autonomic and CNS responses and their possible interdependence. The subjects were stimulated with an increasing amplitude of auditory tones while the auditory event-related potentials (ERPs), the cortical and extracerebral functional near-infrared spectroscopy (fNIRS) signal of standard and short separation channel recordings, the peripheral pulse measured by photoplethysmography, heart rate and electrodermal responses were recorded. Trials with eight tones of equal amplitude were presented. The results showed a parallel increase of activity in ERPs, fNIRS and peripheral responses with the increase in intensity of auditory stimulation. The ERPs, measured as peak-to-peak N1-P2, showed an increase in amplitude with auditory stimulation and a high attenuation from the first presentation with respect to the second to eighth presentations. Peripheral signals and standard and short channel fNIRS responses showed a decrease in amplitude in the high-intensity auditory stimulation conditions. Principal components analysis showed independent sources of variance for the recorded signals, suggesting independent control of the recorded physiological responses. The present results suggest a complex response associated to the increase of auditory stimulation with a fixed amplitude for ERPs, and a decrease in the peripheral and cortical haemodynamic response, possibly mediated by activation of the sympathetic nervous system, constituting a defensive reflex to excessive auditory stimulation.
这项研究的核心问题是什么？听觉刺激会在不同的生理系统中产生反应：心脏、外周血流、皮肤电、皮质和外周血液动力学反应以及听觉事件相关电位。当对听觉刺激做出反应时，所有这些子系统是否会相互关联，暗示存在一个统一的控制中心，还是它们不会相互关联，暗示这些生理反应有独立的控制中心？主要发现及其重要性是什么？听觉感觉门控达到了独立于听觉刺激强度的固定水平的神经活动。使用多元技术揭示了不同生理记录信号存在不同的调节机制。
我们研究了增加听觉刺激幅度对多种自主和中枢神经系统反应及其可能的相互依存关系的影响。在刺激过程中，我们使用强度逐渐增加的听觉音调，同时记录听觉事件相关电位（ERPs）、皮质和脑外功能近红外光谱（fNIRS）信号的标准和短分离通道记录、通过光体积描记法测量的外周脉搏、心率和皮肤电反应。呈现了具有相同幅度的八个音调的试验。结果表明，随着听觉刺激强度的增加，ERPs、fNIRS 和外周反应的活动呈平行增加。ERPs 以峰峰值 N1-P2 测量，随着听觉刺激的增加而增加，与第一次呈现相比，第二次至第八次呈现的振幅衰减很大。外周信号和标准及短通道 fNIRS 反应在高强度听觉刺激条件下的振幅降低。主成分分析显示，记录信号的方差有独立的来源，表明记录的生理反应受到独立控制。目前的结果表明，与 ERPs 的听觉刺激增加幅度固定相关的复杂反应，以及外周和皮质血液动力学反应的减少，可能由交感神经系统的激活介导，构成对过度听觉刺激的防御反射。
