基于虚拟现实的不同情绪视频下的脑电谱特性

目的 研究不同情绪类型的虚拟现实(virtual reality,VR)视频刺激下的脑电(electroencephalogram,EEG)特性,通过分析受试者观看VR视频时的EEG能量,探究不同情绪类型VR视频对受试者神经活动的影响.方法 首先制作3种情绪类型(正性、中性、负性)的VR视频,招募30名健康受试者(男15人,女15人),让他们观看这些视频,并完成情绪评价,同时采集他们观看任务时的8通道EEG信号.然后对EEG信号做预处理,包括滤波、去除坏导联及坏段、去除眼电成分、插值及重参考.对处理干净的信号通过小波变换进行分频,检测θ、α、β频带的信号能量.结果 正性和中性刺激下在全脑范围的各频带脑电能量都显著高于负性刺激;无论何种情绪的VR视频刺激,都表现出右半球的θ能量显著大于左半球的偏侧化现象,且额区和顶区的α能量都显著高于颞区.结论 VR情绪视频能有效诱发特定的情绪,且在VR情绪视频刺激下,存在显著的负性偏向,即负性VR刺激下表现出与正性和中性VR刺激不同的脑电谱特性,表明VR下负性情绪对大脑活动影响的特异性.     

基于深度信念网络脑电信号表征情绪状态的识别研究

随着机器学习技术的快速发展,深度学习等系列算法在一维生理信号处理方面得到了广泛的应用。本文针对脑电(EEG)信号,使用深度学习开源框架中的深度信念网络(DBN)模型识别积极、消极、中性3种情绪状态,并与支持向量机(SVM)进行识别效率的对比,通过采集受试者在不同情绪刺激状态下的脑电信号,利用深度信念网络和支持向量机分别对基于不同特征变换和不同频段的情绪表征数据进行识别。研究结果发现,利用深度信念网络对差分熵(DE)特征进行识别的平均准确率为89.12%±6.54%,与之前的研究相比在同一批数据集上的识别效果更好,同时深度信念网络的分类效果在数值上好于传统的支持向量机(平均分类准确率为84.2%±9.24%),其准确率和稳定性都有相应更好的趋势,另外受试者在3次重复试验中都能得到比较一致的分类准确率(标准差的平均值为1.44%),试验结果较为稳定,试验具有一定的可重复性。研究结果显示,差分熵特征相比于其他特征在分类器中有着更好的分类准确率,此外,方法中使用Beta频段和Gamma频段在情绪识别模型中有着更好的分类效果。综上所述,利用深度学习算法进行情绪识别,能够在准确率上有所提升,对于建立能够更准确地识别情绪状态的辅助识别系统有着一定的借鉴意义。此外,本文研究结果进一步提示可以通过分类结果反演找出与情绪状态最相关的脑区和频段,从而加深对于情绪机制的理解,因此本文在利用脑电信号表征情绪状态的识别研究领域具有一定的学术价值和应用价值,值得更深入的探究。     

重性抑郁症患者听觉负性情绪偏向的电生理证据

目的:通过情绪音乐偏好以及脑电信号相对负波能量半球间不对称性特征研究重性抑郁症(Major Depressive Disorder,MDD)患者的负性情绪偏向。方法:采集22例首发MDD患者及15例健康对照在情绪音乐(愤怒、悲伤和快乐)片段刺激下的实时喜好程度评分以及脑电生理信号。对评分情况、基于脑电信号提取的相对负波能量半球间不对称性指标进行组间差异分析。结果:MDD患者对愤怒情绪音乐的喜好程度显著低于对照组。在愤怒情绪音乐的刺激下,三对额叶电极(F3/F4、F7/F8、FC5/FC6)处的相对负波能量不对称性也显著低于对照组,同时与BDI得分、喜好程度评分分别呈显著负相关和低度正相关。结论:MDD患者对愤怒情绪音乐的主观喜好程度评分及客观脑电生理信号相对负波能量不对称性指标存在改变,提示MDD患者存在听觉负性情绪偏向。     

基于脑电信号时空分布信息的思维特征研究

通过对几种特定形式的思维状态下,脑电信号不同频段能量的时空分布的计算和分析,发现了思维状态对脑电信号的能量分布影响具有不对称性.同时利用这种脑电信号能量的时空分布信息对思维状态进行神经网络分类,并对去除眼动等干扰信号前后的分类结果进行比较.结果表明,这种时空分布信息能有效的表征思维状态的类型,并对干扰信号具有一定的抑制作用,是一种研究脑电和思维认知关系的有效方法.     

基于稀疏贝叶斯网络的情绪脑电的有效性脑网络研究

脑功能网络探索是揭示大脑处理情绪时潜在神经联系的重要手段,稀疏贝叶斯网络(SBN)方法可以分析各区域因果特性及相互影响,逐渐被应用于脑网络的研究中。本文提取了22名被试情绪脑电(EEG)的theta和alpha频段,构建了不同情绪唤醒度的有效性脑网络,并对节点的度、平均聚类系数和特征路径长度进行分析。结果发现:1相比于低唤醒度的EEG信号,左中颞在高唤醒度状态的因果影响都很明显,而右前额的因果影响都不显著;2高唤醒度的平均聚类系数较高,而低唤醒度的特征路径长度较短。     

持续短阵快速脉冲刺激对情绪加工脑网络影响的研究

本文旨在研究持续短阵快速脉冲刺激(c TBS)干预对情绪加工脑功能网络的影响。我们采用c TBS技术对10名受试者的左前额背外侧皮质(DLPFC)区域进行干预,同时记录干预前后受试者进行情绪面孔性别识别任务时的头皮脑电(EEG)信号,然后采用EEG信号相位同步值来衡量两个脑网络节点间的连接强度,并运用网络效率来描述脑区的信息传递效率。研究结果发现,经由c TBS技术干预受试者脑区,再采用情绪面孔图片刺激后,100~300 ms时间窗内的EEG信号的β频段的事件相关功率明显增强;不同的情绪图片刺激下,中性和负性情绪图片刺激的EEG信号全局相位同步值比正性情绪刺激下更高;情绪加工脑网络小世界特性增强。综上所述,本文通过研究左侧DLPFC活跃性改变对情绪加工脑网络的影响,初步探索了情绪加工脑网络机制,为以后的情绪加工脑网络研究提供了参考。     

抑郁症情绪面孔加工的大脑功能网络研究

研究抑郁症患者和正常人在不同的情绪认知任务下大脑功能网络是否存在差异.采用了相位同步的方法以衡量不同脑区间的连接强度,运用网络参数全局和局部效率来刻画大脑的小世界拓扑结构.选取16个抑郁症患者和14个正常被试进行正负情绪面孔搜索的认知任务,同时记录头皮脑电.选择低gamma (30 ～ 50 Hz)和高gamma (50～80 Hz)两个频段的数据建立相位同步矩阵.结果显示:抑郁症患者组的全局相位同步值高于正常组;低gamma频段网络成本区间在(0.25～0.50)内,高gamma频段网络成本区间为(0.25-0.55),情绪加工网络的全局和平均局部效率介于随机网络和规则网络之间,具有小世界特性;在高gamma频段,在最大效费差下(网络成本为0.3),全局效率值在组间有显著性差异,此时局部效率无显著性差异发现;在网络成本为0.5时,发现抑郁症组在左顶颞区和枕区的局部效率显著高于正常组,在情绪间未发现显著性差异.综上反映了抑郁症患者情绪加工网络的异常特性,为抑郁症患者神经网络机制的研究提供了一定的参考.     

音调对音乐情绪反应影响的脑电功能连接研究

目的 探究在倾听不同情绪属性的音乐时音调的变化对大脑功能连通性的影响，以期揭示音调对音乐情绪反应影响的神经机制。方法 首先选取能分别诱发出积极情绪和消极情绪的音乐并制作其升调和降调版本，然后采集10名健康大学生（男、女各5名）听不同版本音乐时的32通道头皮脑电数据，最后分成delta、theta、alpha和beta四个频段计算衡量不同电极间功能连接强弱的指标加权相位滞后指数（weighted phase lag index,wPLI），分析不同条件下脑功能连通性的差异。结果 听消极音乐时，降调版本与原版相比在delta频段下的功能连接显著增强。听积极音乐时，在alpha和beta频段下，与原版相比升高音调显著增强了功能连接，而降低音调显著减弱了功能连接。结论 降低消极音乐的音调使得大脑低频功能连接增加，产生了更放松的音乐体验，表现为效价评分升高；音调的改变会导致听情绪音乐时的大脑功能连通性主要在alpha和beta频段发生变化，表明受试者的音乐感知受到影响，从而导致行为学评分改变。     

精神分裂症和抑郁症患者静息态脑电功率谱熵的对照研究

研究精神分裂症患者(SC)和抑郁症患者(DP)的静息态脑电功率谱熵,深入比较该指标在两种疾病人群中的表现,探究这一指标对两种疾病大脑异常情况的反映。 选择性别、年龄相匹配的精神分裂症、抑郁症患者各100例(男:50,女:50),采集睁眼、闭眼两种状态下的静息态脑电数据;对脑电信号进行信号预处理,并通过独立成分分析实现伪迹校正;基于Welch变换进行功率谱分析,归一化后利用相对功率计算脑电的功率谱熵;采用t检验、方差分析等统计手段,对该指标做统计分析。 结果表明, 在任意相同状态下,精神分裂症组的组平均功率谱熵在每一导联上都低于抑郁症患者组(导联平均功率谱熵:闭眼状态下,SC:1.26; DP:1.32;睁眼状态下,SC:1.33; DP:1.37),且在多数导联上差异显著(P<0.05);对于两组被试,其闭眼状态下的功率谱熵均分别低于睁眼状态下的功率谱熵;对于功率谱熵从睁眼状态至闭眼状态的减少量,两组被试在Fp1、Fp2导联存在显著差异(P<0.05)(Fp1:SC为0.08,DP为0.02;Fp2:SC为0.09,DP为0.02);在睁眼状态下,精神分裂症与抑郁症患者大脑左右半球功率谱熵的不对称性存在差异,精神分裂症组表现出更广的不对称性(呈显著不对称性的电极对:SC有4对,包括F3-F4、O1-O2、F7-F8、T5-T6;DP有2对,包括P3-P4、F7-F8);闭眼状态下二者的不对称性均只显著体现在F7-F8、T5-T6导联(P<0.05)。 功率谱熵这一指标能够敏感直观地描述功率谱的分布情况与不规则程度,进而反映脑电信号的复杂程度以及个体大脑活跃程度。该指标能够作为一项有效参考,反映两种疾病人群在静息态下大脑活动的差异,并有望用于区分精神分裂症与抑郁症。     

基于EEG脑网络的视觉呈现速度对工作记忆影响的研究

随着生活节奏加快，倍速播放在学习过程中被广泛应用，对学习认知活动的影响也逐渐被学者所关注。为探究记忆任务的视觉呈现速度对工作记忆的影响及其机理，本研究从EEG脑网络的视角展开研究。设计了快慢两种呈现速度下的实验范式，并对18名被试的脑电数据进行采集，计算各频段的功率谱并选择具有显著性差异(P<0.05)的频段进行分析。采用格兰杰因果的方法计算不同频段脑区之间的因果关系并构建加权因效性脑网络，分析网络的入度、出度和聚类系数这3种网络特征，并使用支持向量机对快慢状态下的脑网络进行分类。结果显示，在快速视觉呈现状态下，脑网络出入度增加，节点聚类系数进一步加强，且具有显著差异节点主要分布于额叶、顶叶和枕叶，显著高于慢速视觉呈现状态(P<0.05),以各频段入度、出度、聚类系数作为特征对快慢状态下的脑网络进行分类，分类准确率分别最高可达90.96%、90.29%、86.53%。本研究表明，随着视觉呈现速度加快，视觉加工进一步激活，被试的工作记忆意识活动逐渐增强，大脑左半球对语言、推理等认知活动的主导作用也在不断加强。本研究为探究播放速度对学习认知活动的影响提供了新的研究思路，也为学习...     

基于偶极子特征优化的情绪重评同步EEG-fMRI源定位研究

为研究情绪重评时的大脑皮层源活动,针对情绪重评实验范式下采集的15例健康人同步EEG-fMRI数据,首先提出一种新颖的基于偶极子特征优化的融合源定位方法:根据fMRI加权最小范数估计源定位结果,采用20 ms EEG滑动时间窗,提取每个时窗内的偶极子空间融合特征,将其作为动态融合先验进行加权最小范数估计溯源;随后将该结...     

Trait affect moderates cortical activation in response to state affect.

To examine the influence of trait affect on cortical activation during state affect, 32 healthy female participants viewed video clips to induce positive and negative emotional states. Frontal and parietal electroencephalogram (EEG) of the alpha band was assessed while participants imagined the scene of each video that generated the most intense emotions. The results showed that affect-induced frontal asymmetry was moderated by negative trait affect. The difference in frontal asymmetry between positive and negative state affect increased linearly with negative trait affect. Moreover, positive trait affect was negatively correlated with activation in the right-parietal brain region. These results suggest that trait affect moderates the effects of state affect on brain activation.     

Asymmetric eeg changes as method actors generated emotions

Nine method actors recalled personal experiences to create emotional states of sexual arousal or depression. Electroencephalographic (EEG) data recorded from left and right frontal, central, parietal and occipital locations were spectrally analyzed for power in each major frequency band and for coherence among all pairs of channels. Contrasts between the emotion conditions showed less alpha power (greater activation) over the right hemisphere for sexual arousal than for depression. Analysis of coherence topography showed higher coherence in right central and posterior regions during the sexual arousal condition. These data are consistent with previous evidence of right hemisphere contribution to sexual arousal and suggest further that asymmetric patterns of brain activity may be associated with specific emotional states.     

Mothers' frontal EEG asymmetry in response to infant emotion states and mother-infant emotional availability, emotional experience, and internalizing symptoms

This study examined the links between mothers' frontal EEG asymmetry at rest and during videos of their 5- to 8-month-old infants expressing three emotion states (joy, anger/distress, and neutral interest), mother-infant emotional availability (EA) in the home, mothers' depressive and anxious symptoms, and mothers' emotional experience in response to infant emotion cues. Greater relative right frontal activity at rest was associated with greater maternal anxiety, but was unrelated to EA or mother-reported emotional experience in response to infant emotion cues. A shift toward greater relative right frontal activation in response to infant emotional stimuli was associated with lower maternal anxiety, greater mother-infant EA, and mothers' experience of sadness, concern, irritability, and the absence of joy in response to seeing their own infant in distress. These findings suggest that mothers' in the moment empathetic responding to their infant's emotions, indexed by a shift in frontal EEG asymmetry in response to infant emotional displays, is related to mother-infant EA in the home. Implications for conceptualizing parenting risk are discussed.     

Disruption of early event-related theta synchronization of human EEG in alexithymics viewing affective pictures

The 62-channel EEG was recorded while control non-alexithymic (n=21) and alexithymic (n=20) participants viewed sequentially presented neutral, pleasant and unpleasant pictures and subjectively rated them after each presentation. The event-related synchronization (ERS) to these stimuli was assessed in the theta-1 (4-6 Hz) and theta-2 (6-8 Hz) frequency bands. The obtained findings indicate that alexithymia influences perception of only emotional stimuli. Over anterior cortical regions alexithymia vs. control individuals in response to both pleasant and unpleasant stimuli manifested decreased left hemisphere ERS in the early test period of 0-200 ms along with enhanced ERS in response to negative vs. positive and neutral stimuli in the right hemisphere at 200-600 ms after stimulus onset. The findings provide the first EEG evidence that alexithymia construct, associated with a cognitive deficit in initial evaluation of emotion, is indexed by disrupted early frontal synchronization in the upper theta band that can be best interpreted to reflect disregulation during appraisal of emotional stimuli.     

Hemispheric activity of 40 Hz EEG during recall of emotional events: differences between low and high hypnotizables

This study evaluates individual differences in hypnotizability as reflected in waking-state hemispheric engagement during recollection of 3 positively and 3 negatively valenced personal life events. The State-Trait Anxiety Inventory, Maudsley Personality Inventory, Tellegen Absorption Scale and Harvard Group Scale of Hypnotic Susceptibility (Form A) were administered. Electromyogram (EMG) and bilateral electroencephalogram (EEG) activities within the 40-Hz band were recorded during rest and task conditions in 22 high and 21 low hypnotizable women. Self-report rating scores for vividness of visual imagery and emotional feeling of the material recalled were evaluated. The 40-Hz EMG amplitude and both hemisphere 40-Hz EEG densities were obtained. A 40-Hz EEG ratio, as a measure of hemispheric asymmetry, and a hemispheric specificity index were also computed. High hypnotizables showed significantly lower 40-Hz EEG density than low hypnotizables in all experimental conditions. The relationship between lateralization of 40-Hz EEG and emotional processing was moderated by hypnotizability. High hypnotizables, with respect to rest condition, showed an increase of density over both left and right hemispheres during two of the three positive emotional tasks, while they showed a depressed activity over the left and an increased activity over the right during negative emotional tasks. Low hypnotizables, on the other hand, did not exhibit differential hemispheric patterns that could be attributed to different emotional valences. The high group showed greater hemispheric specificity in the predicted direction than the low group. High subjects exhibited greater ratings of absorptive ability and emotional feeling than low subjects. Anxiety and EMG levels did not differ between groups. EMG was dependent on the type of emotion which showed greater activity in the negative emotion condition compared with the positive one.     

Brain temperature asymmetries and emotional perception in chimpanzees, Pan troglodytes

The lateralization of emotion has received a great deal of attention over the last few decades, resulting in two main theories. The Right Hemisphere Theory states that the right hemisphere is primarily responsible for emotional processes, while the Valence Theory suggests that the right hemisphere regulates negative emotion and the left hemisphere regulates positive emotion. Despite the important implications of these theories for the evolution of emotion processes, few studies have attempted to assess the lateralization of emotion in non-human primates. This study uses the novel technique of measuring tympanic membrane temperature (Tty) to assess asymmetries in the perception of emotional stimuli in chimpanzees. The tympanic membrane is an indirect, but reliable, site from which to measure brain temperature, and is strongly influenced by autonomic and behavioral activity. Six chimpanzees were shown positive, neutral, and negative emotional videos depicting scenes of play, scenery, and severe aggression, respectively. During the negative emotion condition, right Tty was significantly higher than the baseline temperature. This effect was relatively stable, long lasting, and consistent across subjects. Temperatures did not change significantly from baseline in the neutral or positive emotion condition, although a significant number of measurements showed increased left Tty during the neutral emotion condition. These data suggest that viewing emotional stimuli results in asymmetrical changes in brain temperature, in particular increased right Tty during the negative emotion condition, evidence of emotional arousal in chimpanzees, and in providing partial support of both the Right Hemisphere and Valence Theories of emotional lateralization in our closest living ancestor.     

Emotion and resilience: a multilevel investigation of hemispheric electroencephalogram asymmetry and emotion regulation in maltreated and nonmaltreated children

The current study was a multilevel investigation of resilience, emotion regulation, and hemispheric electroencephalogram (EEG) asymmetry in a sample of maltreated and nonmaltreated school age children. It was predicted that the positive emotionality and increased emotion regulatory ability associated with resilient functioning would be associated with relatively greater left frontal EEG activity. The study also investigated differences in pathways to resilience between maltreated and nonmaltreated children. The findings indicated that EEG asymmetry across central cortical regions distinguished between resilient and nonresilient children, with greater left hemisphere activity characterizing those who were resilient. In addition, nonmaltreated children showed greater left hemisphere EEG activity across parietal cortical regions. There was also a significant interaction between resilience, maltreatment status, and gender for asymmetry at anterior frontal electrodes, where nonmaltreated resilient females had greater relative left frontal activity compared to more right frontal activity exhibited by resilient maltreated females. An observational measure of emotion regulation significantly contributed to the prediction of resilience in the maltreated and nonmaltreated children, but EEG asymmetry in central cortical regions independently predicted resilience only in the maltreated group. The findings are discussed in terms of their meaning for the development of resilient functioning.     

Anterior electroencephalographic asymmetry changes in elderly women in response to a pleasant and an unpleasant odor

Greater left than right frontal EEG activation has been associated with increased positive and/or decreased negative affect, whereas greater right than left frontal activation has been associated with the opposite pattern. Substantial research has documented the trait properties of asymmetry, as well as responses to pleasant and unpleasant stimuli. The present study examined changes in anterior alpha asymmetries in response to pleasant (vanilla), unpleasant (valerian), and neutral (water) odors. As predicted, vanilla produced relative left frontal activation compared to valerian and water. Frontal asymmetry did not differ in response to valerian compared to water. The results are consistent with the hypothesis that the left frontal region of the brain is involved in positive/approach-related emotion, and extend previous results into the olfactory realm.     

Activation of the right inferior frontal cortex during assessment of facial emotion.

We measured regional cerebral blood flow (rCBF) using positron emission tomography (PET) to determine which brain regions are involved in the assessment of facial emotion. We asked right-handed normal subjects to assess the signalers' emotional state based on facial gestures and to assess the facial attractiveness, as well as to discriminate the background color of the facial stimuli, and compared the activity produced by each condition. The right inferior frontal cortex showed significant activation during the assessment of facial emotion in comparison with the other two tests. The activated area was located within a triangular area of the inferior frontal cortex in the right cerebral hemisphere. These results, together with those of previous imaging and clinical studies, suggest that the right inferior frontal cortex processes emotional communicative signals that could be visual or auditory and that there is a hemispheric asymmetry in the inferior frontal cortex in relation to the processing of emotional communicative signals.