Early glycinergic axon contact with the Mauthner neuron during zebrafish development

One important aspect of empathy is a “resonance mechanism”, which includes emotional cue detection, facial mimicry (measured by electromyography, EMG) and a specific cortical response. This study explored the convergence of these three measures of affective empathy. The twenty students who took part in the study were required to empathise with the situation by entering into the other person's situation. The four emotions portrayed were anger, fear, happiness, and neutral, and the subjects were instructed to make a two-alternative response (emotion or no emotion) to each emotion. A repeated transcranial magnetic stimulation was used to produce a temporary inhibition of the medial prefrontal cortex (MPFC). The results support the hypothesis that there is a direct relationship between emotional cue recognition, EMG-measured facial response and prefrontal activity. First, both facial expression detection and autonomic mimicry in reaction to emotional faces were systematically modulated in response to inhibition of the MPFC. Second, the MPFC was implicated in facial cue detection and the subsequent autonomic response because an impaired performance on both measures was observed when this brain area was inhibited. Third, this effect increased when negative-valenced stimuli (angry and fearful faces) were presented to the subjects. These results revealed a significant effect of the MPFC on both cue detection and facial mimicry that was distinctly related to different types of emotions.     

The psychophysiology of disgust: Differentiating negative emotional contexts with facial EMG

The goals of this study were (a) to examine differing views on the relationship between self-report of emotion and physiological expression of emotion, (b) to differentiate between negative emotional contexts during imagery using facial electromyogram (EMG), and (c) to describe the facial muscle patterning and autonomic physiology of situations that involve expelling or avoiding disgusting sensory stimulation. Fifty subjects imagined situations eliciting disgust, anger, pleasure, and joy in 8-s trials using a tone-cued imagery procedure. Heart rate, skin conductance level, and facial EMG at the corrugator, zygomatic, and levator labii superioris/alesque muscle regions were recorded during imagery, and self-reports of emotion were collected after imagery trials. Self-reports of emotion produced results consistent with the affective categorization of the images. Activity at the levator labii region was higher during disgust than during anger imagery. Corrugator region increase characterized the negative as compared with the positive emotional contents, and activity at the zygomatic region was higher during joy imagery than during the other three emotions. Heart rate acceleration was greater during disgust, anger, and joy imagery than during pleasant imagery. Disgust imagery could be discriminated from anger imagery using facial EMG, and the expressive physiology of disgust was occasioned by the action set of active avoidance or rejection of sensory stimulation.     

Facial Muscle Patterning and Subjective Experience During Affective Imagery: Sex Differences

Facial electromyographic (EMG) activity was recorded from the zygomatic, corrugator, masse-ter and frontalis muscle regions in 30 male and 30 female subjects. Forty-eight items were selected to reflect happy, sad, angry and fearful situations. Subjects imagined each of the items for 40 sec and rated how they felt on a scale tapping the four emotions. The results indicated that for certain emotions, muscle regions and ratings, females (as compared to males): 1) generated facial EMG patterns of greater magnitude (relative to rest) during affective imagery, 2) reported a stronger experience of emotion to the imagery, 3) showed greater within-subject correlations between the experience of emotions and facial EMG, 4) evidenced somewhat higher corrugator and significantly lower masseter EMG activity during rest, and 5) generated greater facial EMG changes during a post-imagery, voluntary facial expression condition. Cultural and biological interpretations of the data are considered. The importance of evaluating gender in psychophysiological studies of emotion is stressed.     

Lateralized Facial Muscle Response to Positive and Negative Emotional Stimuli

Facial electromyography (EMG) was recorded from left and right zygomatic and corrugator muscle regions in response to reflective questions and during voluntary facial expressions. Both muscle regions showed consistent responses to five emotions (happiness, excitement, neutral, sadness, and fear) evoked in the involuntary condition (i.e. reflective questions) and four emotional facial expressions (happiness, excitement, sadness, and fear) self-generated in the voluntary condition. Lateralized responses were found for the zygomatic muscle in the involuntary condition: positive emotion questions elicited relatively greater right muscle activity than left muscle activity, while negative emotion questions elicited relatively greater left muscle activity than right muscle activity. Lateralized responses were found for the corrugator muscle in the voluntary condition, but were not significantly related to type of emotional expression. Sex differences indicating greater lateralization for females were found in some of the measures. The results are consistent with the hypothesized specialization of the left and right cerebral hemispheres for the mediation of positive and negative emotions, respectively.     

Voluntary Facial Action Generates Emotion-Specific Autonomic Nervous System Activity

Four experiments were conducted to determine whether voluntarily produced emotional facial configurations are associated with differentiated patterns of autonomic activity, and if so, how this might be mediated. Subjects received muscle-by-muscle instructions and coaching to produce facial configurations for anger, disgust, fear, happiness, sadness, and surprise while heart rate, skin conductance, finger temperature, and somatic activity were monitored. Results indicated that voluntary facial activity produced significant levels of subjective experience of the associated emotion, and that autonomic distinctions among emotions: (a) were found both between negative and positive emotions and among negative emotions, (b) were consistent between group and individual subjects' data, (c) were found in both male and female subjects, (d) were found in both specialized (actors, scientists) and nonspecialized populations, (e) were stronger when the voluntary facial configurations most closely resembled actual emotional expressions, and (f) were stronger when experience of the associated emotion was reported. The capacity of voluntary facial activity to generate emotion-specific autonomic activity: (a) did not require subjects to see facial expressions (either in a mirror or on an experimenter's face), and (b) could not be explained by differences in the difficulty of making the expressions or by differences in concomitant somatic activity.     

Relationships between facial electromyography and subjective experience during affective imagery

Sixty subjects were exposed for 40 s each to 48 imagery situations designed to reflect happy, sad, angry and fearful conditions. Facial electromyographic (EMG) activity from zygomatic, corrugator, masseter and lateral frontalis muscle regions was recorded, and experienced emotion was measured on a scale tapping these four emotions. Results showed that: (1) zygomatic activity reliably differentiated happy imagery, corrugator activity reliably differentiated sad imagery, but masseter activity did not differentiate angry imagery and lateral frontalis activity did not differentiate fearful imagery; (2) different intensities of specific emotional imagery situations evoked the expected differential patterns of self-report and EMG; (3) higher correlations between self-report and EMG for ‘present’, rather than ‘future’ ratings of experienced emotion emerged for positive affect only; and (4) the use of a standardized imagery scale, rather than the self-generated, personally-relevant affective situations used in previous studies, allowed for more sensitive measurement of the relationship between facial muscle activity and subjective experience of emotion during affective imagery.     

Appraisal frames of pleasant and unpleasant pictures alter emotional responses as reflected in self-report and facial electromyographic activity

Emotional pictures elicit responses across experiential, behavioral and physiological systems. The magnitude of these responses can be modulated by altering one's interpretation of emotional stimuli. Previous studies have indicated that appraisal frames affect subsequent interpretations of upcoming stimuli so as to alter self-reported emotions, ERP activity and autonomic responses. No studies to date have examined the effect of appraisal frames on expressive behaviors as measured by facial EMG. This study aims to test the hypothesis that appraisal frames can alter both emotional experience and facial expression and attempts to examine their effect on the temporal unfolding of facial expressions. Participants (N=20) were exposed to 125 pairs of appraisal frames (neutral or negative/positive) followed by neutral, unpleasant, or pleasant pictures reflecting five conditions: unpleasant-negative, unpleasant-neutral, pleasant-positive, pleasant-neutral and neutral-neutral. Results indicate that the unpleasant-negative compared to the unpleasant-neutral condition led to greater self-reported unpleasantness and arousal, as well as greater corrugator activity, and the pleasant-positive compared to the pleasant-neutral condition led to greater self-reported pleasantness and zygomaticus activity; modulation of facial responses became evident 0.5-1.0s after stimulus onset. These results suggest that appraisal frames effectively alter both emotional experience and facial expressions.     

Pattern Recognition of Self-Reported Emotional State from Multiple-Site Facial EMG Activity During Affective Imagery

A multivariate pattern-classification system was developed for the study of facial electromy-ographic (EMG) patterning in 12 female subjects during affect-laden imagery and for posed facial expressions. A parameter-extraction procedure identified the dynamic EMG signal properties which accorded the maximal degree of self-reported emotion discrimination. Discriminant analyses on trialwise EMG vectors allowed assessment of specific EMG-site conformations typifying rated emotions of happiness, sadness, anger, and fear. The discriminability among emotion-specific EMG conformations was correlated with subjective ratings of affective-imagery vividness and duration. Evidence was obtained suggesting that the EMG patterns encoded complex, “blended” reported affective states during the imagery. Classification analyses produced point-predictions of reported emotional states in 10 of the 12 subjects, and provided the first computer pattern recognition of self-reported emotion from psychophysiological responses.     

The effect of cognitive reappraisal on physiological reactivity and emotional memory

We investigated the effect of cognitive reappraisal on emotional arousal, facial expressivity and subsequent memory. Men and women viewed emotionally negative pictures while they attempted to either increase or decrease negative emotions elicited by the pictures, or to simply view the pictures. Neutral pictures were also presented with instructions to simply view the pictures. Concurrent changes in emotional arousal and valence were assessed with skin conductance responses (SCRs) and facial corrugator electromyographic responses (EMG), respectively. Picture memory was assessed with an immediate recall test and a delayed recognition test. Relative to simply viewing pictures, voluntary reappraisal to increase negative emotion generated greater facial corrugator EMG and SCR responses, and reappraisal to decrease negative emotion generated decreased corrugator EMG responses. Men showed enhanced recognition for pictures presented during the increase and decrease conditions, whereas women showed comparable recognition performance across all regulation conditions. The modulation of subsequent recognition memory associated with decreasing emotion was inversely associated with changes in physiological responses. Our results suggest that sex is an important factor to consider in determining how reappraisal-induced physiological changes are associated with subsequent changes in memory. These findings contribute to our understanding of how reappraising emotion exerts both immediate and enduring influences on physiological responses and subsequent memory.     

Psychophysiological response patterns to positive and negative film stimuli

The aim of the present study was to investigate differential emotional response patterns to film stimuli by multimodal assessment of mood ratings, perception of bodily sensations, salivary cortisol, autonomic variables and facial electromyogram (EMG). Film stimuli, chosen to elicit positive and negative emotional states, were presented to 12 subjects with general anxiety disorder and 12 controls. Changes in mood, bodily sensations, autonomic activity (heart rate, respiration rate and skin conductance), facial EMG activity (corrugator and zygomatic muscle region) and salivary cortisol were measured. Analyses revealed differential changes in all response systems except for respiration rate and salivary cortisol. Although high-anxious subjects did not differ from controls in their average responses to the negative film stimuli, there is a tendency of a greater coherence of emotional response components in generalized anxiety subjects. However, spontaneous facial expressions to positive and negative film stimuli were associated with augmented electrodermal activity within both groups. Results are interpreted in light of directional response fractionation, dimensional approaches of emotion, and the facial feedback literature.     

Facial reactions, autonomic activity and experienced emotion: a three component model of emotional conditioning

The present study was designed to evaluate whether aversively conditioned responses to facial stimuli are detectable in all three components of the emotional response system, i.e. the expressive/behavioral, the physiological/autonomic and the cognitive/experienced component of emotion. Two groups of subjects were conditioned to angry or happy facial expression stimuli using a 100 dB noise as UCS in a differential aversive conditioning paradigm. The three components of the emotional response system were measured as: Facial-EMG reactions (corrugator and zygomatic muscle regions); autonomic activity (skin conductance, SCR; SCR half recovery time, T/2; heart rate, HR); and ratings of experienced emotion. It was found that responses in all components of the emotional response system were detectable in the angry group as greater EMG and autonomic resistance to extinction and greater self-reported fear. More specifically the angry group showed a resistant conditioning effect for the facial-EMG corrugator muscle that was accompanied by resistant conditioning for SCR frequency, slower SCR recovery, resistant conditioning in HR and a higher self-reported fear than the happy group. Thus, aversive conditioning to angry facial stimuli induce a uniform negative emotional response pattern as indicated by all three components of the emotional response system. These data suggest that a negative 'affect program' triggers responses in the different emotional components. The results suggest that human subjects are biologically prepared to react with a negative emotion to angry facial stimuli.     

For Distinguished Early Career Contribution to Psychophysiology: Award Address, 1988

The aim of this paper is to review data from my laboratory, which were collected in an attempt to determine whether the facial EMG response is a general component of the emotional reaction. In a number of studies it was found that facial reactions: first, are spontaneously elicited and differ according to the kind of emotional stimuli to which subjects are exposed; second, are sensitive to learning; third, are consistent with how the subjects perceive the stimuli and their own specific emotions; fourth, are congruent with autonomic responses; fifth, are more pronounced for females than for males; and finally, differ among subjects with specific fears. These data converge to indicate that facial muscle activity is a general component of the emotional reaction and demonstrate that the facial EMG technique is a sensitive tool for measuring emotional reactions.     

Psychophysiological responses as indices of affective dimensions

The startle reflex, facial electromyogram (EMG), and autonomic nervous system responses were examined during imagery varying in affective valence and arousal. Subjects (N= 48) imagined affective situations during tone-cued 8-strials. Startle blink magnitudes were larger and latencies faster during negatively valent than during positively valent conditions and during high-arousal than during low-arousal conditions. Greatest heart rate acceleration and fastest and largest skin conductance responses to startle probes occurred during high-arousal imagery. Zygomatic and orbicularis oculi facial muscle activities were higher during high-arousal imagery, whereas corrugator muscle activity was higher during low-arousal imagery. Zygomatic and corrugator activity also varied with emotional valence. The startle and facial EMG responses are most parsimoniously organized by the negative affect (NA) and positive affect (PA) dimensions, respectively. This NA/PA framework integrates previous research, dimensional theories of emotional behavior, and physiological assessment of pathological emotion.     

P300 habituation from auditory single-stimulus and oddball paradigms.

The habituation of auditory P300 event-related brain potential (ERP) from single-stimulus paradigm was evaluated and compared to that from oddball paradigm. Three task conditions were: oddball with a button press (oddball/press) response, single-stimulus with a button-press (single-stimulus/press) response and a silent count (single-stimulus/count) response. The oddball/press condition demonstrated larger P300 amplitude and longer latency overall than either single-stimulus condition, but P300 amplitude decreased and peak latency increased similarly over successive trial blocks for all three tasks. Thus, the oddball and single-stimulus ERP tasks produce analogous changes under repeated measurements and indicate that the single-stimulus task can serve as an alternative method for eliciting the P300 in applied and clinical settings.     

Emotional conflict occurs at an early stage: Evidence from the emotional face–word Stroop task

The perceptual processing of emotional conflict was studied using electrophysiological techniques to measure event-related potentials (ERPs). The emotional face–word Stroop task in which emotion words are written in prominent red color across a face was use to study emotional conflict. In each trial, the emotion word and facial expression were either congruent or incongruent (in conflict). When subjects were asked to identify the expression of the face during a trial, the incongruent condition evoked a more negative N170 ERP component in posterior lateral sites than in the congruent condition. In contrast, when subjects were asked to identify the word during a trial, the incongruent condition evoked a less negative N170 component than the congruent condition. The present findings extend our understanding of the control processes involved in emotional conflict by demonstrating that differentiation of emotional congruency begins at an early perceptual processing stage.     

Effects of believes and expectations about self and others on emotional recognition of facial expressions: from the perspective of adult attachment

This study aimed at examining how adult attachment styles as believes and expectations about self and others affected emotional recognition of facial expressions. In this study, hypotheses were framed based on the perspective of attachment dimensions. One hundred and sixty one undergraduates observed positive, negative, and neutral facial expressions as stimulus, and rated the extent to which each stimuli expressed several kinds of emotion. The main results were as follows. Generally, either anxious or avoidant individuals were less likely to perceive positive emotion (happy) from facial expressions, and anxious and less avoidant individuals perceived other-oriented negative emotions (anger, disgust, and contempt). In addition, avoidant individuals were less likely to perceive positive emotion from positive facial expressions. On the other hand, from negative facial expressions, anxious and less avoidant individuals were more likely to perceive other-oriented negative emotions, and anxious individuals were less likely to perceive positive emotion. The results were discussed from the perspective of adult attachment theory.     

Electrophysiological correlates of emotional and structural face processing in humans

In order to study brain potentials related to decoding of facial expressions of emotions and those, related to basic perception of faces 16 right-handed subjects performed tasks on facial emotion recognition and perception of blurred faces and objects. Electroencephalograph (EEG) recordings during performance of the tasks revealed similar event-related potentials during the presentation of faces at 120 and 170 ms after stimulus onset in both of the tasks but significant differences in amplitudes between 180 and 300 ms. Whereas faces in the emotion recognition task produced high amplitudes in that latency range, potentials in response to faces in the blurred object condition were virtually absent. These data point to the assumption that decoding of facial expressions starts early in the brain and might be processed separately from basic stages of face perception.     

Event-related skin conductance responses to musical emotions in humans

While the reasons underlying musical emotions are unclear, music is nevertheless a powerful elicitor of emotion, and as such, may induce autonomic nervous system responses. One typical measure of this neural pathway is the skin conductance response (SCR). This response generally depends upon stimulus arousal, one of the two motivational determinants of emotion. The objective of the present study was to verify whether emotional reactions to music elicit such event-related autonomic responses. To this aim, four musical emotions varying in arousal were employed: fear, happiness, sadness and peacefulness. SCRs were found to be greater with the two more stimulating emotions, fear and happiness, as compared to the two more relaxing emotions, sadness and peacefulness (P<0.05). In addition, subjects' ratings of the emotional clarity for each excerpt did not parallel the corresponding SCRs magnitudes. The results show that SCRs can be evoked and modulated by musical emotional arousal, but are not sensitive to emotional clarity. While several studies have been performed with visual scenes and environmental sounds, the present study brings similar evidence from the musical domain.     

Subject-independent emotion recognition based on physiological signals: a three-stage decision method

Background

Collaboration between humans and computers has become pervasive and ubiquitous, however current computer systems are limited in that they fail to address the emotional component. An accurate understanding of human emotions is necessary for these computers to trigger proper feedback. Among multiple emotional channels, physiological signals are synchronous with emotional responses; therefore, analyzing physiological changes is a recognized way to estimate human emotions. In this paper, a three-stage decision method is proposed to recognize four emotions based on physiological signals in the multi-subject context. Emotion detection is achieved by using a stage-divided strategy in which each stage deals with a fine-grained goal.

Methods

The decision method consists of three stages. During the training process, the initial stage transforms mixed training subjects to separate groups, thus eliminating the effect of individual differences. The second stage categorizes four emotions into two emotion pools in order to reduce recognition complexity. The third stage trains a classifier based on emotions in each emotion pool. During the testing process, a test case or test trial will be initially classified to a group followed by classification into an emotion pool in the second stage. An emotion will be assigned to the test trial in the final stage. In this paper we consider two different ways of allocating four emotions into two emotion pools. A comparative analysis is also carried out between the proposal and other methods.

Results

An average recognition accuracy of 77.57% was achieved on the recognition of four emotions with the best accuracy of 86.67% to recognize the positive and excited emotion. Using differing ways of allocating four emotions into two emotion pools, we found there is a difference in the effectiveness of a classifier on learning each emotion. When compared to other methods, the proposed method demonstrates a significant improvement in recognizing four emotions in the multi-subject context.

Conclusions

The proposed three-stage decision method solves a crucial issue which is ’individual differences’ in multi-subject emotion recognition and overcomes the suboptimal performance with respect to direct classification of multiple emotions. Our study supports the observation that the proposed method represents a promising methodology for recognizing multiple emotions in the multi-subject context.

     

Facial expression recognition and emotional regulation in narcolepsy with cataplexy

Cataplexy is pathognomonic of narcolepsy with cataplexy, and defined by a transient loss of muscle tone triggered by strong emotions. Recent researches suggest abnormal amygdala function in narcolepsy with cataplexy. Emotion treatment and emotional regulation strategies are complex functions involving cortical and limbic structures, like the amygdala. As the amygdala has been shown to play a role in facial emotion recognition, we tested the hypothesis that patients with narcolepsy with cataplexy would have impaired recognition of facial emotional expressions compared with patients affected with central hypersomnia without cataplexy and healthy controls. We also aimed to determine whether cataplexy modulates emotional regulation strategies. Emotional intensity, arousal and valence ratings on Ekman faces displaying happiness, surprise, fear, anger, disgust, sadness and neutral expressions of 21 drug‐free patients with narcolepsy with cataplexy were compared with 23 drug‐free sex‐, age‐ and intellectual level‐matched adult patients with hypersomnia without cataplexy and 21 healthy controls. All participants underwent polysomnography recording and multiple sleep latency tests, and completed depression, anxiety and emotional regulation questionnaires. Performance of patients with narcolepsy with cataplexy did not differ from patients with hypersomnia without cataplexy or healthy controls on both intensity rating of each emotion on its prototypical label and mean ratings for valence and arousal. Moreover, patients with narcolepsy with cataplexy did not use different emotional regulation strategies. The level of depressive and anxious symptoms in narcolepsy with cataplexy did not differ from the other groups. Our results demonstrate that narcolepsy with cataplexy accurately perceives and discriminates facial emotions, and regulates emotions normally. The absence of alteration of perceived affective valence remains a major clinical interest in narcolepsy with cataplexy, and it supports the argument for optimal behaviour and social functioning in narcolepsy with cataplexy.