(1)文章主要研究了三种情绪状态(紧张、恐惧和兴奋)下面部热特征的变化;
(2)文章简单的提出了一个功能红外成像(Functional Infrared Imaging) 这样一个概念及其特征(可供替代的、非接触的、非侵略性);
(3)实验对象(10名健康的志愿者)、实验仪器(数字红外摄像机、PowerLab ADInstruments system (机能实验系统))、试验方法(ground thru measurements)和环境要求
(4)疼痛刺激引起的痛苦和恐惧:对每个实验者进行5-8次突然的电击刺激,相邻两次的时间间隔是随机的。根据实验分析测试者的皮肤泌汗反应(SSR)和交感神经热反应(STR)。
实验结果表明:每次刺激的反应时间为(0.3 ± 0.2S),每个测试者的总反应时间为(2 ± 1.5S),手掌和面部温度分别下降(0.2 ± 0.2C)和(0.6 ± 0.3C),交感神经热反应(STR)持续的时间要比面部泌汗系统反应(SSR)持续的时间平均要长3秒或者更多,STR的反应时间在3.5±1秒内变动,而温度下降的持续时间大约为3-4秒;
(5)心理不适引起的情绪性发汗(紧张):主要是诱导测试对象通过斯特鲁测试产生一种紧张和尴尬情绪。测试过程:根据显示器上的指示点击鼠标左右键。当指示物为紧张状态时,从中可以观察测试者是否会由于按错键而皮电反应增强并且心跳率增加。
实验结果:错误的任务执行并不会对面部温度产生明显的影响,皮电反应和心跳率都没有发生明显的增加。相反,当测试者面对该情况感到明显不适时将表现出很强的情绪性发汗,尤其是在嘴部。
(6)性唤起引起的兴奋情绪:通过让测试者观看两种不同类型的电影,引发两种不同的情绪进行测试。
实验结果表明:在兴奋状态下,面部温度增加,尤其是眼眶周围、嘴部周围和前额区域。
Thermal Signatures of Emotional Arousal: A Functional Infrared Imaging Study
(情绪反应的热特征:功能红外成像技术研究)
Abstract — Functional Infrared Imaging was used to study the facial thermal signatures of three fundamental emotional conditions: stress, fear and pleasure arousal. Facial cutaneous temperature and its topographic distribution exhibited specific features clearly correlated to emotional arousal and concomitant measures of standard physiological signals of the sympathetic activity. The results of this study indicate functional infrared imaging as an alternative, touch less, non invasive method for assessing individual’s emotional arousal in psychophysiology.
功能红外成像技术用于研究三种基本情感状态(紧张、恐惧和愉快)下的面部热特征。面部皮肤温度及其位置分布所表现出的具体特征显然同情绪反应及同时伴随着标准生物特征信号的量度有关。本文研究的结果表明:功能红外成像技术是一种用于估定个体心理生理上情感产生的可供替代的、非接触的、非侵略性的方法。
I. INTRODUCTION
Emotional reactions are important manifestations of the human beings behavior. They may constitute the response to a wide variety of external stimuli, like alarms, psychological pressure, or also pleasant situations, etc. Several studies on the activation of such reactions have been performed through the measurement of several physiological parameters expressing sympathetic nervous system activity, like skin sympathetic response, heart beat and/or breath modulations, facial electromyography activity and EEG investigation. Monitoring these parameters is, in some way, invasive(侵略性) because requires contact between the subject and the device and the time necessary to the evaluation is not short. The spontaneous response may then result affected. Traditional channels are not suitable for the noninvasive and quick monitoring of emotional response, while such features are requested, for example, by neuro-psychologists and security surveillance systems, as well.
情感反应是人类行为的一个重要表现方面。它主要由一系列的外部刺激产生,如:恐慌、心理压力或者处于一个宜人的地方等等。对这类反应刺激的一些研究已经针对表示交感神经系统活动的一系列生理参数方面开始了实施,例如:皮肤交感神经反应、心搏或者呼吸调整、面部肌电图变动以及脑电图(EEG)调查等。这些参数的测量在某些方面来说是具有侵犯性的,因为这要求采集对象和设备必须进行配合操作,况且取值的这段时间并不是很短。无意识的反应很可能会影响最终的结果。传统的方法不适于非侵犯性和快速情感反应追踪的要求,当然这些参数也可以通过如神经-心理学知识和安全警戒系统等获取。。
On the other hand, short term thermal effects related to the activity of the sympathetic system are well known, but not quantified(不能定量研究). Measuring subtle thermal effects due to emotional arousal may provide useful information about the sympathetic activity, since the skin temperature depends on the cutaneous blood perfusion, local tissue metabolism, and sudomotor response, all of them being in turn controlled by the sympathetic system.
另一方面,关于交感神经系统活动引起的短期热效应是众所周知的,但却很难对其进行定量研究。由情绪反应引起的细微热效应的测量将会对交感神经的活动提供有用的信息,这是因为人体的皮肤温度依赖于皮肤血液灌流、局部组织代谢以及泌汗神经反应等因素,而所有的这些因素都依次由交感神经系统控制。
Functional infrared imaging (fIR) consists of the dynamic recording of the skin temperature distribution, and its analysis, both in the spatial and in the time domains. fIR relies on high- temperature and time-spatial resolution digital devices coupled to real-time processing. In this study we propose to use fIR to detect and, when possible, to quantify the emotional arousal related to a variety of stimuli.
功能红外成像(FIR)包括皮肤温度分布的动态记录及其分析组成,两者都是在空间域和时间域进行测量的。FIR必须依靠结合有实时处理器的高温时空分辨率的数字设备。在本研究中,我们打算通过FIR来探测,如有可能便定量分析由一系列刺激刺激引起的情绪反应。,
II. MATERIALS AND METHOD (材料和方法)
The dynamic of the thermal effects eventually related to the emotional arousal induced by several kinds of stimuli was studied in 10 healthy volunteers. ©The local ethical committee approved the study; the subjects signed consent forms. Normal responses to neuro psychological interview aimed at assessing personality profile and absence of sympathetic diseases were assumed as inclusion criteria.
热效应的动态性最终同在研究中对10名健康自愿者进行多中刺激所诱发的情绪反应有关。要求志愿者无神经系统的及疾病。
The thermal recording was done by means of a digital infrared camera AEG 256 PtSi, 3-5 μm, spectral range, NETD = 0.04 K, frame rate = 50 frame/sec.
红外热图像是通过一架数字红外摄像机采集而来(参数如上)。
Recording was performed in a controlled climate room, maintained at (23 ± 1) °C and 50-60 % relative humidity. The subjects observed acclimation procedures and wash out from substances possibly interfering with basal sympathetic activity [1].(图像记录采集时的环境及采集对象的状态)
Synchronously to fIR recording, ground thru measurements were also performed via a PowerLab (机能实验系统)ADInstruments system, able to record at 1kHz sampling rate heart beat rate, breathing rate, galvanic skin response, palm temperature, and arterial pressure. The following sections describe the stimuli delivered to the subjects and the results reported. (图像采集的同时还需要测量和记录的数据内容)
III. SUB-PAINFUL STIMULI (疼痛刺激)
Sudomotor Skin Response (SSR) to unexpected sub-painful electric stimulation of the median nerve at wrist was measured simultaneously to the Sympathetic Thermal Response (STR). A trigger stimulus, synchronous with delivery of the electrical stimulation, was used to monitor the electrical signal continuously acquired from two electrodes positioned over the second and the third fingers ipso lateral to the stimulus, and to mark the onset of the thermal phenomenon to be investigated on the infrared camera output. Typically, 5 to 8 unexpected stimuli were delivered to each subject. To avoid habituation, rest period lasting between two successive stimuli was randomly changed. Thermal imaging of the contra lateral to the stimulated wrist palm and of the subject face was performed to record the STR.
伴随着对交感神经热反应测试,对腕部的中部神经进行突然的电击对皮肤泌汗系统反应(SSR)进行测试。通常对每一个测试者进行5至8次突然刺激。为了避免适应,两次相邻刺激间的时间间隔是随机的。
Clear-cut(清晰的) SSR were recorded after each stimulus for all of the subjects (Figure 1). The latency of the electrical signal was (0.3 ± 0.2) sec(每个刺激的反应时间) and the overall response was over in (2 ± 1.5) sec(总体反应时间). Synchronous palm and face temperature decreases were observed, (0.2 ± 0.2) °C and (0.6 ± 0.3) °C(手掌和脸部的温度下降幅度), respectively (Figure 1, Figure 2, and Figure 3). Face sudomotor response(脸部泌汗反应) to all of the delivered stimuli was also reported (Figure 4). Longer time scale characterized the STR, in average 3 sec longer than for SSR(交感神经热反应持续的时间要比面部泌汗系统反应持续的时间平均要长3秒或者更多). In particular, STR response latency was varying between (3.5 ± 1) sec, and an overall lasting of temperature decrease was about 3-4 sec)(STR的反应时间在3.5±1秒内变动,而温度下降的持续时间大约为3-4秒). Successively, the sweat evaporation induced thermoregulatory responses which lasted for 15-20 sec, in average. (接下来汗水蒸发降低体温的反应过程平均持续15-20秒)
Fig. 1. Overall average Galvanic Skin Response(皮电反应) to sub-painful stimuli.
Fig. 2. Overall average Palm Sympathetic Thermal Response(手掌感应神经热反应) to sub-painful stimuli.
IV. EMOTIONAL SWEATING DUE TO PSYCHOLOGICAL DISCOMFORT (心理不适引起的情绪性发汗)
For this study, the subjects were asked to perform a stroop test(斯特鲁测验) in presence of other unknown people looking at the subjects with attention. The study was designed to induce in the participating subjects a status of stress and embarrassment when wrongly performing the stroop test task.(主要是诱导测试对象通过斯特鲁测试产生一种紧张和尴尬情绪) The task consisted of pressing right or left mouse button accordingly to indications displayed on a screen. As indicator of stress status, we searched for increased galvanic skin responses and increased heart beat rate right after wrong button pressing (through ANOVA test).
测试过程:根据显示器上的指示点击鼠标左右键。当指示物为紧张状态时,从中可以观察测试者是否会由于按错键而皮电反应增强并且心跳率增加。
Subjects not influenced by the presence of other unknown people and not feeling discomfort because of wrong task execution did not exhibit significant changes in the facial temperature during the whole recording. No significant increase was found neither in heart beat rate and galvanic skin responses. On the contrary, subject feeling significant discomfort to face the situation exhibited large emotional sweating activity, especially around the mouth (Figure 5). Interestingly, the same general behaviour of SSR and face STR described in Section III was found in this experiment.
当遇到陌生人或者感到不适时并不会影响测试者,因为在整个记录过程中,错误的任务执行并不会对面部温度产生明显的影响。皮电反应和心跳率都没有发生明显的增加。相反,当测试者面对该情况感到明显不适时将表现出很强的情绪性发汗,尤其是在嘴部(图5)。有趣的是,第III部分描述的皮肤泌汗系统反应(SSR)和交感神经热反应(STR)的一般特性也会在该实验中出现。
Fig. 3. Overall average Face Sympathetic Thermal Response(STR) to sub-painful stimuli.Q
Fig. 4. Facial Sudomotor Sympathetic Thermal Response(SSR).
Left) Rest temperature distribution before receiving sub-painful stimulus;
Right) Temperature decrease and onset of sudomotor sympathetic sweating, especially appreciable on the perioral and forehead regions(口周围和前额区域).
V. SEXUAL AROUSAL(性唤起)
In the previous sections, we focused on searching STR features associated to adverse stimuli, like fear to feel pain and stress. To assess whether or not facial thermal signatures could be also found in pleasant conditions, we enrolled 10 healthy young male volunteers for studying their facial STR associated to sexual arousal. They were asked to watch 2 different types of movies, sport and erotic, in alternate sequence, for three times. Each sport movie lasted 3 minutes, while the erotic one lasted 5 minutes.(实验对象及实验结果)
以前的章节着重研究了不利刺激下的交感神经热反应(STR)特征,如因疼痛和紧张而引起的恐惧。
As ground thru method to control whether the subjects were sexually aroused or not, their penis turgidity was measured through a pneumatic device connected to the PowerLab ADInstruments.
Together with the arousal activation, subtle increase in facial temperature was observed, especially in the periorbital(眼眶周围), forehead(前额), and lips regions(嘴唇区域) (Figure 6).
Applying bioheat models developed in [2 - 3], we calculated the facial blood perfusion rate change. Blood perfusion rate during sexual-based content video stimuli was higher than during non sexual-based stimuli (p < 0.01, t test), (Figure 7).
根据文献【2-3】提供的热传导模型,我们可以计算出面部血液灌注率的改变。
Fig. 5: Emotional sweating(情绪性发汗): delivery of emotional pressure(情绪压力) or stress stimulation (on the right) changes the rest (on the left) temperature distribution.
VI. DISCUSSION AND CONCLUSIONS (讨论及结论)
In this study we attempted to assess whether thermal signatures of different emotional conditions exist and reliably report emotional arousal(不同情绪状态下的热特征). We considered three different conditions: stress induced by psychological pressure and other people’ judgement(他人判断和心理压力引起的紧张), pain and fear to feel pain(疼痛引起的痛苦和恐惧), and sexual arousal and excitement(性唤起和兴奋). In all of these conditions, the STR(交感神经热反应) provided an appreciable measure of the sympathetic activity(交感神经活动) and correlated to the other sympathetic physiological signals(其他相关的交感神经生理特征).
(1) Stress discomfort resulted in emotional sweating(情绪性出汗);
(2) pain or fear to feel pain resulted in a general decrease of the facial temperature(面部温度下降) induced by both peripheral vasoconstriction (外围血管收缩)and sudomotor activity(泌汗神经活动);
(3) sexual arousal resulted in increased skin blood perfusion rate in specific face regions(不同区域的面部血液灌注率增加) and, particularly, on the forehead (cutaneous projection of the corrugators muscle(皱眉肌), i.e. increased attention), over the lips (increased perfusion of mucosa tissue(粘膜组织) for augmented sensitivity), and the nose.
The thermal signatures were definitively consistent with ground thru methods’ findings.(热特征最终同ground thru方法的研究结果相一致)
The present study suggests that fIR(功能红外成像) is a reliable method for psychophysiological(心理生理学) studies aimed at assessing emotional arousal and response. To date, some authors consider fIR as a possible alternative to polygraph methods for deception detection(欺骗检测) [3]. The results of this preliminary study suggest that specific thermal signatures related to specific emotional conditions exist, but further studies are needed to assess the specificity and the sensitivity of the method.
目前的研究表明:功能红外成像(FIR)技术对基于估计情绪诱发和反应的心理生理学研究是一种可靠的方法。到目前为止,一些作者认为FIR可能会替代用于欺骗检测的测谎器技术。这个初步研究的结果表明:具体的热特征同特定的情绪状态相关。而将来的研究则要侧重于估计这种方法的特性和灵敏度。