Department of Information Engineering and the Bioengineering and Robotics Research Center "E. Piaggio," School of Engineering, University of Pisa, Pisa, Italy.
Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Unit, University of Siena, Siena, Italy.
Psychophysiology. 2018 Oct;55(10):e13199. doi: 10.1111/psyp.13199. Epub 2018 May 20.
Noninvasive, objective quantitative techniques to gauge emotional states are fundamental for clinical psychology as they overcome subjective bias of currently used questionnaires. To this end, we investigated brain oscillatory EEG activity during caresslike, affective haptic elicitation conveyed on the forearm at two force (strength of the caress) and three velocity (velocity of the caress) levels. Thirty-two healthy subjects (16 female) were asked to assess each haptic stimulus in terms of arousal (i.e., intensity of emotional perception) and valence (i.e., pleasantness/unpleasantness of emotional perception) scores, according to the circumplex model of affect. Changes in brain oscillations were quantified through spectral and functional connectivity analyses. EEG power spectra were estimated through the individual α frequency peak. Results, expressed in terms of p-value topographic maps, revealed a suppression of α, β, and γ oscillations over the contralateral somatosensory cortex during unpleasant caresses performed with the lowest force (2 N) and the highest velocity (65 mm/s). Conversely, pleasant caresses at the highest force were associated with a significant decrease of EEG oscillatory activity over the midfrontal region, at frequency bands including α, β, and γ. A correlation analysis showed that EEG γ power from the somatosensory area was linked to caressing force. The more unpleasant the affective cutaneous stimuli, the more the brain dynamics decrease in activity all over the scalp, primarily showing a suppression of α power over the midfrontal cortex. These results also pave the way for the design of haptic systems eliciting a given emotional state.
用于临床心理学的非侵入性、客观的定量技术来评估情绪状态是非常重要的，因为它们克服了目前使用的问卷的主观偏见。为此，我们研究了在前臂上以两种力（抚摸的强度）和三种速度（抚摸的速度）进行抚摸样情感触觉诱发时的脑振荡 EEG 活动。32 名健康受试者（16 名女性）被要求根据情感的环面模型评估每个触觉刺激的唤醒（即情绪感知的强度）和效价（即情绪感知的愉悦/不愉快）得分。通过频谱和功能连接分析来量化脑振荡的变化。通过个体α频率峰值来估计 EEG 功率谱。以 p 值地形图表示的结果表明，在施加最低力（2 N）和最高速度（65 mm/s）的不愉快抚摸时，对侧体感皮层的α、β和γ振荡被抑制。相反，在最高力下进行的愉快抚摸与中频前额区域 EEG 振荡活动的显著降低有关，包括α、β和γ频带。相关分析表明，来自体感区域的 EEG γ 功率与抚摸力有关。情感皮肤刺激越不愉快，大脑活动的整体减少越多，主要表现为中前额皮质α功率的抑制。这些结果也为设计诱发特定情绪状态的触觉系统铺平了道路。
