Zygomatic Activity Research Articles

Testing emotional response coherence assumptions: Comparing emotional versus non-emotional states.

Although central to theories of emotion, emotional response coherence, that is, coordination among various emotion response systems, has received inconsistent empirical support. This study tests a basic assumption of response coherence, that is, that it characterizes emotional states defining their beginning and end. To do so, we (a) compare response coherence between emotional versus non-emotional states and (b) examine how emotional coherence changes over time, before, during, and after an emotional episode. Seventy-nine participants viewed neutral, pleasant, and unpleasant film clips and rated continuously how pleasant they felt (experience) before (anticipation), during, and after (recovery) each clip. Autonomic physiological arousal responses (skin conductance level, heart rate; physiology) and facial expressions (corrugator, zygomatic activity; expression) were recorded. Within-person cross-correlations between all emotional response pairs were calculated for each phase. Analyses comparing coherence during emotional versus neutral film viewing showed that only experience-expression coherence was higher for emotional versus neutral films, indicating specificity for emotional states. Examining coherence across phases indicated that coherence increased from anticipation to emotional film viewing, as expected, for experience-expression and experience-physiology pairs (SCL only). Of those pairs, increased coherence returned to baseline during recovery, as theoretically assumed, only for experience-corrugator activity coherence. Current findings provide empirical support for theoretical views of response coherence as a defining feature of emotional episodes, but mostly for the coherence between experience and facial expressions. Further research needs to investigate the role of sympathetic arousal indices, as well as the role of response coherence in emotional recovery.

Alterations in facial expressions in individuals at risk for psychosis: a facial electromyography approach using emotionally evocative film clips.

Negative symptoms such as blunted facial expressivity are characteristic of schizophrenia. However, it is not well-understood if and what abnormalities are present in individuals at clinical high-risk (CHR) for psychosis. This experimental study employed facial electromyography (left zygomaticus major and left corrugator supercilia) in a sample of CHR individuals (N = 34) and healthy controls (N = 32) to detect alterations in facial expressions in response to emotionally evocative film clips and to determine links with symptoms. Findings revealed that the CHR group showed facial blunting manifested in reduced zygomatic activity in response to an excitement (but not amusement, fear, or sadness) film clip compared to controls. Reductions in zygomatic activity in the CHR group emerged in response to the emotionally evocative peak period of the excitement film clip. Lower zygomaticus activity during the excitement clip was related to anxiety while lower rates of change in zygomatic activity during the excitement video clip were related to higher psychosis risk conversion scores. Together, these findings inform vulnerability/disease driving mechanisms and biomarker and treatment development.

Effect of the Use of a Cream with Leucine and Lactic Acid Associated with Electrostimulation in Contouring and Facial Tonus: A Randomized Clinical Controlled Trial

Evidence has supported the use of leucine as a promising agent for the maintenance of muscle tone. This study aimed to assess the combined effect of leucine and cream-based lactic acid (novel cosmetic product), associated with the use of surface electrical stimulation to improve contour and facial tonus in women. A total of 23 women were randomly allocated into two groups: Experimental (EG)—use of the leucine-based cream and lactic acid + electrostimulation for facial toning (mean intensity 13 Hz and protocol in progression); and placebo (GP)—use of the placebo cream (without the addition of leucine and lactic acid) + stimulation with the same protocol as the EG. Each group used their cream daily and underwent the intervention protocol three x/week with stimulation for 40 min, for a total of 8 weeks. Three main outcomes were reported: angular variation of facial contour by means of photogrammetry, muscle tone through the electromyographic activity of the masseter and zygomatic muscles during rest and functional tasks of biting and smiling. A significant effect of the intervention and between the groups was obtained for the experimental group against the placebo group for facial contour and muscle tone. An increased muscular activity of the masseter (average 28%) when smiling, and a reduction of zygomatic activity (in average 41%) when biting were found. The use of cream containing leucine and lactic acid combined with electrostimulation contributes to the improvement of facial contour and muscle tone when biting and smiling.

Pictures of social interaction prompt a sustained increase of the smile expression and induce sociability

Viewing pictures of social interaction can facilitate approach behaviors. We conducted two studies to investigate if social interaction cues, empathy, and/or social touch modulate facial electromyographic (EMG) reactivity (as evidenced by the zygomaticus major and corrugator supercilii muscles) and mood states. We presented bonding pictures (depicting social interaction) and control pictures (without social interaction) while continuously recording zygomatic and corrugator EMG activities. In both studies, picture blocks were paired by valence and arousal. All participants were college students. In study 1, participants (n = 80, 47 women) read relevant priming texts immediately before viewing each block of 14 pictures. In study 2, participants did not read (n = 82, 63 women) priming texts before each block of 28 pictures. In study 1 and study 2, participants also completed mood states questionnaires to assess sociability and altruistic behavior. Empathy and social touch frequency were also assessed by self-reported questionnaires. In both studies, bonding pictures increased the zygomatic activity and the self-reported sociability feeling compared to control pictures. Only in study 2, bonding pictures decreased median corrugator activity compared to control pictures. We concluded that social interaction cues were efficient to increase sociability and prompt a sustained smile expression regardless of priming texts.

The effect of being watched on facial EMG and autonomic activity in response to another individual\u2019s facial expressions

We tested if facial reactions to another person’s facial expressions depend on the self-relevance of the observed expressions. In the present study (n = 44), we measured facial electromyographic (zygomatic and corrugator) activity and autonomic arousal (skin conductance) responses to a live model’s smiling and neutral faces. In one condition, the participant and the model were able to see each other normally, whereas in the other condition, the participant was led to believe that the model could not see the participant. The results showed that the increment of zygomatic activity in response to smiling faces versus neutral faces was greater when the participants believed they were being watched than it was when the participants believed they were not being watched. However, zygomatic responses to smiles did not differ between the conditions, while the results suggested that the participants’ zygomatic responses to neutral faces seemed to attenuate in the condition of believing they were being watched. Autonomic responses to smiling faces were greater in the belief of being watched than in the belief of not being watched condition. The results suggest that the self-relevance of another individual’s facial expression modulates autonomic arousal responses and to a lesser extent facial EMG responses.

Facial reactions to violent and comedy films: Association with callous–unemotional traits and impulsive aggression

ABSTRACTThe current study adds to prior research by investigating specific (happiness, sadness, surprise, disgust, anger and fear) and general (corrugator and zygomatic muscle activity) facial reactions to violent and comedy films among individuals with varying levels of callous–unemotional (CU) traits and impulsive aggression (IA). Participants at differential risk of CU traits and IA were selected from a sample of 1225 young adults. In Experiment 1, participants (N = 82) facial expressions were recorded while they watched violent and comedy films. Video footage of participants' facial expressions was analysed using FaceReader, a facial coding software that classifies facial reactions. Findings suggested that individuals with elevated CU traits showed reduced facial reactions of sadness and disgust to violent films, indicating low empathic concern in response to victims' distress. In contrast, impulsive aggressors produced specifically more angry facial expressions when viewing violent and comedy films. In Experiment 2 (N = 86), facial reactions were measured by monitoring facial electromyography activity. FaceReader findings were verified by the reduced facial electromyography at the corrugator, but not the zygomatic, muscle in response to violent films shown by individuals high in CU traits. Additional analysis suggested that sympathy to victims explained the association between CU traits and reduced facial reactions to violent films.

Emotional facial expressions evoke faster orienting responses, but weaker emotional responses at neural and behavioural levels compared to scenes: A simultaneous EEG and facial EMG study

In the current study, electroencephalography (EEG) was recorded simultaneously with facial electromyography (fEMG) to determine whether emotional faces and emotional scenes are processed differently at the neural level. In addition, it was investigated whether these differences can be observed at the behavioural level via spontaneous facial muscle activity. Emotional content of the stimuli did not affect early P1 activity. Emotional faces elicited enhanced amplitudes of the face-sensitive N170 component, while its counterpart, the scene-related N100, was not sensitive to emotional content of scenes. At 220–280ms, the early posterior negativity (EPN) was enhanced only slightly for fearful as compared to neutral or happy faces. However, its amplitudes were significantly enhanced during processing of scenes with positive content, particularly over the right hemisphere. Scenes of positive content also elicited enhanced spontaneous zygomatic activity from 500–750ms onwards, while happy faces elicited no such changes. Contrastingly, both fearful faces and negative scenes elicited enhanced spontaneous corrugator activity at 500–750ms after stimulus onset. However, relative to baseline EMG changes occurred earlier for faces (250ms) than for scenes (500ms) whereas for scenes activity changes were more pronounced over the whole viewing period. Taking into account all effects, the data suggests that emotional facial expressions evoke faster attentional orienting, but weaker affective neural activity and emotional behavioural responses compared to emotional scenes.

Is empathy necessary to comprehend the emotional faces? The empathic effect on attentional mechanisms (eye movements), cortical correlates (N200 event-related potentials) and facial behaviour (electromyography) in face processing

The present research explored the effect of social empathy on processing emotional facial expressions. Previous evidence suggested a close relationship between emotional empathy and both the ability to detect facial emotions and the attentional mechanisms involved. A multi-measure approach was adopted: we investigated the association between trait empathy (Balanced Emotional Empathy Scale) and individuals' performance (response times; RTs), attentional mechanisms (eye movements; number and duration of fixations), correlates of cortical activation (event-related potential (ERP) N200 component), and facial responsiveness (facial zygomatic and corrugator activity). Trait empathy was found to affect face detection performance (reduced RTs), attentional processes (more scanning eye movements in specific areas of interest), ERP salience effect (increased N200 amplitude), and electromyographic activity (more facial responses). A second important result was the demonstration of strong, direct correlations among these measures. We suggest that empathy may function as a social facilitator of the processes underlying the detection of facial emotion, and a general “facial response effect” is proposed to explain these results. We assumed that empathy influences cognitive and the facial responsiveness, such that empathic individuals are more skilful in processing facial emotion.

Social hierarchies and emotions: Cortical prefrontal activity, facial feedback (EMG), and cognitive performance in a dynamic interaction

In the present research, we manipulated the perceived superior/inferior status during a competitive cognitive task. In two experiments, we created an explicit and strongly reinforced social hierarchy based on incidental rating on an attentional task. Based on our hypotheses, social rank may influence nonverbal cues (such as facial mimic related to emotional response), cortical lateralized activity in frontal areas (brain oscillations), and cognitive outcomes in response to rank modulation. Thus, the facial mimic (corrugators vs. zygomatic muscle activity), frequency bands (delta, theta, alpha, beta), and real cognitive performance [(error rate (ER); response times (RTs)] were considered. Specifically, a peer-group comparison was enrolled and an improved (experiment 1, N = 29) or decreased (experiment 2, N = 31) performance was artificially manipulated by the experimenter. Results showed a significant improved cognitive performance (decreased ER and RTs), an increased zygomatic activity (positive emotions), and a more prefrontal left-lateralized cortical response in the case of a perceived increased social ranking. On the contrary, a significant decreased cognitive performance (increased ER and RTs), an increased corrugators activity (negative emotions), and a less left-lateralized cortical response were observed as a consequence of a perceived decreased social ranking. Moreover, the correlational values revealed a consistent trend between behavioral (RTs) and EMG and EEG measures for both experiments. The present results suggest that social status not only guides social behavior, but it also influences cognitive processes and subjects’ performance.

What do facial expressions of emotion express in young children? The relationship between facial display and EMG measures

The present paper explored the relationship between emotional facial response and electromyographic modulation in children when they observe facial expression of emotions. Facial responsiveness (evaluated by arousal and valence ratings) and psychophysiological correlates (facial electromyography, EMG) were analyzed when children looked at six facial expressions of emotions (happiness, anger, fear, sadness, surprise and disgust). About EMG measure, corrugator and zygomatic muscle activity was monitored in response to different emotional types. ANOVAs showed differences for both EMG and facial response across the subjects, as a function of different emotions. Specifically, some emotions were well expressed by all the subjects (such as happiness, anger and fear) in terms of high arousal, whereas some others were less level arousal (such as sadness). Zygomatic activity was increased mainly for happiness, from one hand, corrugator activity was increased mainly for anger, fear and surprise, from the other hand. More generally, EMG and facial behavior were highly correlated each other, showing a "mirror" effect with respect of the observed faces.

High-frequency rTMS on DLPFC increases prosocial attitude in case of decision to support people

Engaging in prosocial behavior was explored in the present research, by investigating the role of dorsolateral prefrontal cortex (DLPFC) in modulation of intention to support other people and of emotional attuning as it was expressed by facial feedback (electromiography, EMG). High-frequency rTMS was applied on DLPFC to 25 subjects when they were required to choose to directly intervene or not to support other people in emotionally valenced social situations (cooperative, noncooperative, conflictual, neutral contexts). Two control conditions were included in the experimental design to control the simple stimulation effect (sham condition with absence of TMS stimulation) and the location effect (control site condition with Pz stimulation). In comparison with sham and control condition, rTMS stimulation induced increased prosocial behavior in all the emotional situations. Moreover, as a function of valence, zygomatic (for positive situations) and corrugators (for negative situations) muscle activity was increased, with significant effect by DLPFC stimulation which induced a “facilitation effect”. In addition, negative situations showed a higher rTMS impact for both behavioral and EMG responsiveness. Finally, prosocial behavior was found to be predicted (regression analysis) by EMG variations, as a function of the negative versus positive valence. The prefrontal circuit was suggested to support emotional responsiveness and facial feedback in order to facilitate the prosocial behavior.

Psychophysiological assessment of emotional processing in patients with borderline personality disorder with and without comorbid substance use.

This study assessed physiological measures for the study of emotional dysregulation associated with borderline personality disorder (BPD). Two patient groups, the first comprised of individuals with BPD only (n = 16) and the second, individuals with BPD and co-occurring substance-use disorder (SUD; n = 35), and a group of healthy controls (n = 45) were shown standardized pictures of varying valance and arousal levels. Affective modification of startle eye-blink responses, heart rate, facial electromyography (EMG, including corrugator and zygomatic activity), and skin-conductance responses were collected during picture presentation and during a brief recovery period. Startle data during picture presentation indicated a trend toward the expected increase in startle response magnitude to negative stimuli, to be moderated by group status, with patients with BPD-SUD showing a lack of affective modification and the BPD-only group showing similar affective modification to that of controls. Heart-rate data suggested lower reactivity to negative pictures for both patient groups. Differences in facial EMG responses did not provide a clear pattern, and skin-conductance responses were not significantly different between groups. The data did not suggest differences between groups in recovery from exposure to the emotional stimuli. The startle and heart-rate data suggest a possible hyporeactivity to emotional stimuli in BPD.

Contextual Modulation of Physiological and Psychological Responses Triggered by Emotional Stimuli

A series of emotional events successively occur in temporal context. The present study investigated how physiological and psychological responses are modulated by emotional context. Skin conductance response (SCR), heart rate, corrugator activity, zygomatic activity, and subjective feelings during emotional picture viewing were measured. To create an emotional context, a unpleasant or pleasant picture was preceded by three types of pictures, i.e., unpleasant, pleasant, and neutral pictures, resulting in six pairings. The results showed that viewing an unpleasant picture attenuated pleasant feelings induced by the following pleasant picture. On the other hand, preceding pleasant pictures decreased SCR to the following pictures. The effects of contextual modulation on emotional responses might be due to the informative function of pre-existing feelings; unpleasant feelings signal a threatening environment, whereas pleasant feelings signal a benign environment. With respect to facial muscle activities, viewing a pleasant picture decreased corrugator activity in response to the preceding picture. These findings suggest several types of contextual modulation effects on psychological, autonomic, and somatic responses to emotional stimuli.

Age-related differences in affective responses to and memory for emotions conveyed by music: a cross-sectional study

There is mounting evidence that aging is associated with the maintenance of positive affect and the decrease of negative affect to ensure emotion regulation goals. Previous empirical studies have primarily focused on a visual or autobiographical form of emotion communication. To date, little investigation has been done on musical emotions. The few studies that have addressed aging and emotions in music were mainly interested in emotion recognition, thus leaving unexplored the question of how aging may influence emotional responses to and memory for emotions conveyed by music. In the present study, eighteen older (60–84 years) and eighteen younger (19–24 years) listeners were asked to evaluate the strength of their experienced emotion on happy, peaceful, sad, and scary musical excerpts (Vieillard et al., 2008) while facial muscle activity was recorded. Participants then performed an incidental recognition task followed by a task in which they judged to what extent they experienced happiness, peacefulness, sadness, and fear when listening to music. Compared to younger adults, older adults (a) reported a stronger emotional reactivity for happiness than other emotion categories, (b) showed an increased zygomatic activity for scary stimuli, (c) were more likely to falsely recognize happy music, and (d) showed a decrease in their responsiveness to sad and scary music. These results are in line with previous findings and extend them to emotion experience and memory recognition, corroborating the view of age-related changes in emotional responses to music in a positive direction away from negativity.

Self‐report measures, facial feedback, and personality differences (BEES) in cooperative vs. noncooperative situations: Contribution of the mimic system to the sense of empathy

The present study integrated three different measures of emotional empathic behavior in a social context: verbal self-report measures (empathic response, emotional involvement, emotional significance, and valence), facial mimicry (activity of corrugator and zygomaticus muscles), and personal response to the Balanced Emotional Empathy Scale (BEES). Participants were presented with different interpersonal scene types (cooperation, noncooperation, conflict, indifference). Firstly, self-rating on empathy, emotional involvement, and valence varied as a function of interpersonal context. Secondly, corrugator activity increased in response to conflictual and noncooperative situations; zygomatic activity increased in response to cooperative situations. Third, high- and low-BEES subjects showed different empathic behavior: High-empathic subjects were more responsive to empathy-related situations than low-empathic subjects. The convergence and divergence of these multidimensional measures was discussed.

Filial versus romantic love: Contributions from peripheral and central electrophysiology

A major problem in recent neuroscience research on the processing of loved familiar faces is the absence of evidence concerning the elicitation of a genuine positive emotional response (love). These studies have two confounds: familiarity and arousal. The present investigation controlled for both factors in female university students. Two categories of loved faces were chosen: one with higher familiarity but lower emotionality (fathers) and the other with higher emotionality but lower familiarity (romantic partners). Unfamiliar and baby faces were used as control faces. Central and peripheral electrophysiological measures as well as subjective indices of valence, arousal, and dominance were recorded. Results support the conclusion that viewing loved familiar faces elicits an intense positive emotional reaction that cannot be explained either by familiarity or arousal. The differences between romantic and filial love appeared in the magnitude of some peripheral and subjective indices of emotionality (zygomatic activity, valence, arousal, and dominance), that were higher for images of the romantic partners, and one central index of familiarity (the P3 amplitude), that was higher for images of the fathers.

Motivational Processing and Choice Behavior During Television Viewing: An Integrative Dynamic Approach

This study was designed to further our understanding of the central role of motivational activation in mediated information processing and media choice. To do this, a dynamic model was developed to formalize the dynamic effects of three basic motivational input variables (arousing content, positivity, and negativity) on four physiological output measures (heart rate, skin conductance level, corrugator activity, and zygomatic activity) and a behavioral choice measure of television channel selection. The input and output variables were selected based on extensive theoretical and empirical research that has explicated static relationships among these variables. In general, the findings of the dynamic modeling approach were consistent with the previous literature using traditional static statistical methods. However, this study also theoretically extended the previous work.

Hedonic reactivity to visual and olfactory cues: Rapid facial electromyographic reactions are altered in anorexia nervosa

Though it has been suggested that hedonic processing is altered in anorexia nervosa (AN), few studies have used objective measures to assess affective processes in this eating disorder. Accordingly, we investigated facial electromyographic, autonomic and subjective reactivity to the smell and sight of food and non-food stimuli, and assessed more particularly rapid facial reactions reflecting automatic processing of pleasantness. AN and healthy control (HC) women were exposed, before and after a standardized lunch, to pictures and odorants of foods differing in energy density, as well as to non-food sensory cues. Whereas the temporal profile of zygomatic activity in AN patients was typified by a fast drop to sensory cues within the 1000ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800–1000ms time window. In contrast, pleasantness ratings discriminated the two groups only for high energy density food cues suggesting a partial dissociation between objective and subjective measures of hedonic processes in AN patients. The findings suggest that the automatic processing of pleasantness might be altered in AN, with the sensitivity to reward being modulated by controlled processes.

Affective processing of loved faces: Contributions from peripheral and central electrophysiology

Research on the neural mechanisms of face identity constitutes a fruitful method to explore the affective contributions to face processing. Here, we investigated central and peripheral electrophysiological indices associated with the perception of loved faces. Subjects viewed black-and-white photographs of faces that belonged to one of five categories: loved ones, famous people, unknown people, babies, and neutral faces from the Eckman and Friesen system. Subcategories of loved faces included romantic partner, parents, siblings, second-degree relatives, and friends. Pictures were presented in two separate blocks, differing in viewing time (0.5s vs. 4s), inter-stimulus interval (1.2s vs. 18s), and number of face presentations (200 vs. 50). Heart rate, skin conductance, electromyography of the zygomatic muscle, and event-related potentials (ERPs) were obtained while participants passively viewed the pictures. Subjective picture ratings of valence, arousal, and dominance were obtained at the end of the experiment. Both central and peripheral electrophysiological measures differentiated faces of loved ones from all other categories by eliciting higher heart rate, skin conductance, and zygomatic activity, as well as larger amplitudes of the late ERP components P3 and LPP. Loved faces also resulted in higher valence and arousal, but lower dominance ratings. Additional differences were found among subcategories of loved faces. Faces of romantic partners elicited higher physiological (skin conductance and zygomatic activity) and subjective (emotional arousal) responses than parents, siblings, or friends, suggesting that looking at the image of someone we love evokes strong positive affect and emotional/cognitive arousal that go beyond a feeling of familiarity or simple recognition.

Emotional Empathy and Facial Reactions to Facial Expressions

This study investigates whether people high in emotional empathy are more facially reactive than are people low in emotional empathy when exposed to pictures of angry and happy facial expressions. Facial electromyographic activity was measured from the corrugator and the zygomatic muscle regions. In accordance with the predictions, the high empathic group reacted with larger corrugator activity to angry as compared to happy faces and with larger zygomatic activity to happy faces. However, the low empathic group did not differentiate between the angry and happy stimuli at all. The high empathic group, as compared to the low empathic group, also rated the angry faces as expressing more anger and the happy faces as being happier. It is concluded that high empathic people are particularly sensitive in reacting with facial reactions to facial expressions and that this ability is accompanied by a higher level of empathic accuracy.