Human Psychobiology Laboratory, Experimental Psychology Department, University of Sevilla, Sevilla, Spain.
Physiol Rep. 2022 Jul;10(13):e15372. doi: 10.14814/phy2.15372.
The present study aims to analyze the systemic response to auditory stimulation by means of hemodynamic (cephalic and peripheral) and autonomic responses in a broad range of auditory intensities (70.9, 77.9, 84.5, 89.5, 94.5 dBA). This approach could help to understand the possible influence of the autonomic nervous system on the cephalic blood flow. Twenty-five subjects were exposed to auditory stimulation while electrodermal activity (EDA), photoplethysmography (PPG), electrocardiogram, and functional near-infrared spectroscopy signals were recorded. Seven trials with 20 individual tones, each for the five intensities, were presented. The results showed a differentiated response to the higher intensity (94.5 dBA) with a decrease in some peripheral signals such as the heart rate (HR), the pulse signal, the pulse transit time (PTT), an increase of the LFnu power in PPG, and at the head level a decrease in oxygenated and total hemoglobin concentration. After the regression of the visual channel activity from the auditory channels, a decrease in deoxyhemoglobin in the auditory cortex was obtained, indicating a likely active response at the highest intensity. Nevertheless, other measures, such as EDA (Phasic and Tonic), and heart rate variability (Frequency and time domain) showed no significant differences between intensities. Altogether, these results suggest a systemic and complex response to high-intensity auditory stimuli. The results obtained in the decrease of the PTT and the increase in LFnu power of PPG suggest a possible vasoconstriction reflex by a sympathetic control of vascular tone, which could be related to the decrease in blood oxygenation at the head level.
本研究旨在通过广泛的听觉强度（70.9、77.9、84.5、89.5、94.5 dBA）下的血液动力学（头部和外周）和自主反应来分析对听觉刺激的全身反应。这种方法可以帮助理解自主神经系统对头部血流的可能影响。25 名受试者在暴露于听觉刺激时，记录皮肤电活动（EDA）、光体积描记术（PPG）、心电图和功能近红外光谱信号。呈现了七个试验，每个试验包含 20 个单独的音调，每个音调对应五个强度。结果表明，对较高强度（94.5 dBA）的反应存在差异，一些外周信号（如心率（HR）、脉搏信号、脉搏传输时间（PTT）、PPG 中的 LFnu 功率增加）和头部水平的氧合和总血红蛋白浓度降低。在从听觉通道回归视觉通道活动后，获得了听觉皮层去氧血红蛋白的减少，表明在最高强度下可能存在活跃的反应。然而，其他措施，如 EDA（相位和紧张）和心率变异性（频率和时域），在强度之间没有显示出显著差异。总之，这些结果表明对高强度听觉刺激的全身性和复杂反应。PPG 中 PTT 的减少和 LFnu 功率的增加表明，可能存在交感神经控制血管张力的血管收缩反射，这可能与头部水平的血氧饱和度降低有关。
