Subnormal short-latency facial mimicry responses to dynamic emotional facial expressions in male adolescents with disruptive behavior disorders and callous-unemotional traits

Using still pictures of emotional facial expressions as experimental stimuli, reduced amygdala responses or impaired recognition of basic emotions were repeatedly found in people with psychopathic traits. The amygdala also plays an important role in short-latency facial mimicry responses. Since dynamic emotional facial expressions may have higher ecological validity than still pictures, we compared short-latency facial mimicry responses to dynamic and static emotional expressions between adolescents with psychopathic traits and normal controls. Facial EMG responses to videos or still pictures of emotional expressions (happiness, anger, sadness, fear) were measured. Responses to 500-ms dynamic expressions in videos, as well as the subsequent 1500-ms phase of maximal (i.e., static) expression, were compared between male adolescents with disruptive behavior disorders and high (n = 14) or low (n = 17) callous-unemotional (CU) traits, and normal control subjects (n = 32). Responses to still pictures were also compared between groups. EMG responses to dynamic expressions were generally significantly smaller in the high-CU group than in the other two groups, which generally did not differ. These group differences gradually emerged during the 500-ms stimulus presentation period but in general they were already seen a few hundred milliseconds after stimulus onset. Group differences were absent during the 1500-ms phase of maximal expression and during exposure to still pictures. Subnormal short-latency mimicry responses to dynamic emotional facial expressions in the high-CU group might have negative consequences for understanding emotional facial expressions of others during daily life when human facial interactions are primarily dynamic.     

Schizophrenic patients show facial reactions to emotional facial expressions

Facial reactions in schizophrenic patients were assessed via electromyography (EMG) in response to pictures of facial expressions. Male patients and nonpatient controls viewed photographs of positive and negative facial expressions while EMG activity from the corrugator and zygomatic muscle regions was recorded. Both schizophrenic patients and controls exhibited greater zygomatic reactivity in response to positive pictures than in response to negative pictures and greater corrugator reactivity in response to negative pictures than in response to positive pictures. Schizophrenic patients exhibited greater corrugator reactivity than did nonpatient controls. Implications for understanding emotion expression and perception in schizophrenic patients are discussed.     

Looking at facial expressions: dysphoria and facial EMG

Previous research on interpersonal deficits among dysphoric individuals has been equivocal, with some studies finding that dysphoric persons show an increase in negative behavior and other studies finding no group differences. Most studies in this area have employed self-report instruments and behavioral coding systems to examine interpersonal displays. Using a different approach, we examined facial electromyography (EMG) reactivity to pictures of happy and unhappy expressions among dysphoric persons. Dysphoric and non-dysphoric persons viewed happy and unhappy facial expressions while zygomatic EMG and corrugator EMG activity was recorded. Results indicated that both groups showed the appropriate increase in corrugator EMG to unhappy expressions; however, dysphoric persons did not show the expected increase in zygomatic EMG activity to happy expressions while the control participants did show this response. Unexpectedly, the dysphoric group displayed an increase in corrugator EMG activity (e.g. frown response) to the happy facial expressions. These findings indicate that dysphoric persons have impaired interpersonal reactivity that is specific to happy facial displays.     

Right hemisphere representation of autonomic conditioning to facial emotional expressions

In this experiment, a lateralized right hemisphere effect was found for electrodermal associative learning to facial emotional expressions. Sixty-two subjects were presented simultaneously with a slide of a happy face in the right or left visual half field (VHF) and a slide of an angry face in the opposite VHF. Four groups were formed by the combination of the two VHF positions of angry/happy faces and the administration/omission of shock unconditioned stimuli. The results showed that simultaneous presentation of the angry face to the right hemisphere and the happy face to the left hemisphere, together with shock, resulted in a strong conditioned association with the angry face and a relatively weak association with the happy face. Furthermore, simultaneous presentation of the angry face to the left hemisphere and the happy face to the right hemisphere, together with shock, resulted in a relatively weak association with both stimuli. No significant differences were found for the no-shock control groups. The present results confirm previous findings of a right hemisphere advantage for representation of associative learning.     

Facial reactions to happy and angry facial expressions: evidence for right hemisphere dominance

Previous research on asymmetric effects of emotional expression and brain-hemispheric asymmetry has supported opposing theories of hemispheric dominance in the control of emotional reactions. In the present study, 32 subjects were exposed to pictures of happy and angry facial stimuli while facial electromyographic (EMG) activity from the zygomatic major and the corrugator supercilii muscle regions was detected from the left and right sides of the face. The subjects reacted spontaneously and rapidly with larger zygomatic EMG activity to happy facial stimuli and larger corrugator EMG activity to angry stimuli. These distinct reactions were significantly larger on the left side of the face. It is concluded that the present results support the hypothesis that the right brain hemisphere is predominantly involved in the control of spontaneously evoked emotional reactions.     

Sociality of facial expressions in immersive virtual environments: a facial EMG study

Immersive virtual environment technology is increasingly used by psychologists as a tool for researching social influence in realistic, yet experimentally controllable, settings. The present study demonstrates the validity and reliability of facial electromyography as a marker of affect in immersive virtual environments and further shows that the mere presence of virtual humans is enough to elicit sociality effects on facial expressiveness. Participants viewed pleasant and unpleasant images in a virtual room either alone or with two virtual humans present. The patterns of smiling and frowning activity elicited by positive and negative stimuli in the virtual environment were the same as those found in laboratory settings. Moreover, when viewing positive stimuli, smiling activity was greater when two agents were present than in the alone condition. The results provide new psychophysiological evidence for the potency of social agents in immersive virtual environments.     

Interaction of facial expressions and familiarity: ERP evidence

There is mounting evidence that under some conditions the processing of facial identity and facial emotional expressions may not be independent; however, the nature of this interaction remains to be established. By using event-related brain potentials (ERP) we attempted to localize these interactions within the information processing system. During an expression discrimination task (Experiment 1) categorization was faster for portraits of personally familiar vs. unfamiliar persons displaying happiness. The peak latency of the P300 (trend) and the onset of the stimulus-locked LRP were shorter for familiar than unfamiliar faces. This implies a late perceptual but pre-motoric locus of the facilitating effect of familiarity on expression categorization. In Experiment 2 participants performed familiarity decisions about portraits expressing different emotions. Results revealed an advantage of happiness over disgust specifically for familiar faces. The facilitation was localized in the response selection stage as suggested by a shorter onset of the LRP. Both experiments indicate that familiarity and facial expression may not be independent processes. However, depending on the kind of decision different processing stages may be facilitated for happy familiar faces.     

Electromyographic responses to static and dynamic avatar emotional facial expressions

Facial muscular reactions to avatars' static (neutral, happy, angry) and dynamic (morphs developing from neutral to happy or angry) facial expressions, presented for 1 s each, were investigated in 48 participants. Dynamic expressions led to better recognition rates and higher intensity and realism ratings. Angry expressions were rated as more intense than happy expressions. EMG recordings indicated emotion-specific reactions to happy avatars as reflected in increased M. zygomaticus major and decreased M. corrugator supercilii tension, with stronger reactions to dynamic as compared to static expressions. Although rated as more intense, angry expressions elicited no significant M. corrugator supercilii activation. We conclude that facial reactions to angry and to happy facial expressions hold different functions in social interactions. Further research should vary dynamics in different ways and also include additional emotional expressions.     

Conditioning with facial expressions of emotion: Effects of CS sex and age

Two experiments examined the effects of facial expressions of emotion as conditioned stimuli (CSs) on human electrodermal conditioning and on a continuous measure of expectancy of the shock unconditioned stimulus. In Experiment 1, the CS+ was a picture of a person displaying an angry face and CS? was a neutral face. For half of the subjects, the expressions were depicted by males, for the other half by females. Male subjects showed larger skin conductance responses to pictures of males than did females. The responding of female subjects was the same regardless of the sex of the person in the picture. In Experiment 2, the CS+ and CS? were pictures of an angry or a happy face. For half of the subjects, the expressions were depicted by adult males, for the other half by preadolescent males, Subjects displayed greater differentiation when an adult male depicting anger was employed as the CS+ than when a preadolescent male depicting anger was the CS+. There were no differences when an adult or a child displayed happiness.     

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 1000 ms following stimulus onset, HC showed a larger EMG reactivity to pictures in a 800-1000 ms 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.     

Electromyographic feedback in the treatment of bilateral facial paralysis: A case study

Electromyographic feedback in the treatment of facial paralysis has been shown to be a useful alternative to surgical procedures. In this paper we report on the partial recovery of a 7-year-old patient with congenital bilateral facial paralysis (Moebius syndrome) that had been considered untreatable by medical specialists. Biofeedback of electromyographic activity was provided together with specific instructions, social reinforcement, and exercises that the patient carried out at home. The rehabilitation training lasted 1 year, during which there was a substantial increase in the electromyographic activity of the muscles on both sides of the face. A follow-up after 1 year of discontinuing the treatment showed that the muscle activity had been maintained and that there was a marked improvement in the patient's mood and facial expression.This research was partially supported by the Programa de Apoyo a las Divisiones de Estudios de Posgrado (PADEP) of the Coordinación General de Estudios de Posgrado of the Universidad Nacional Autónoma de México and by Sabbatical Fellowship 48367 granted by the Consejo Nacional de Ciencia y Tecnologia to the first author, who is presently on leave of absence at Coquitlam College, Coquitlam, B.C., Canada.     

Emotional reactivity,emotional eating,and obesity: A naturalistic study

Laboratory studies indicate that obese individuals are more emotionally reactive and more likely to overeat when distressed than are those of normal weight. These studies were conducted under highly artificial conditions, however, and their generality outside of the laboratory remains largely untested. The present study compared the emotional reactivity and emotional eating of normal and overweight female college students in the natural environment. Subjects self-monitored their food intake and mood just prior to each instance of eating for 12 consecutive days. The results indicated that obese subjects were more emotionally reactive and more likely to engage in emotional eating than normals, but these findings applied only to snacks, not to meals. Correlational analyses indicated that emotional distress associated with snacks and emotional eating associated with both snacks and meals were related to subjects' percentage overweight. The two groups did not differ on any measure of positive emotions of consumption following positive emotions, nor were these two variables related to percentage overweight. The theoretical and clinical implications of these findings are briefly discussed.     

Electromyographic responses to emotional facial expressions in 6-7year olds: A feasibility study

Preliminary studies have demonstrated that school-aged children (average age 9-10years) show mimicry responses to happy and angry facial expressions. The aim of the present study was to assess the feasibility of using facial electromyography (EMG) as a method to study facial mimicry responses in younger children aged 6-7years to emotional facial expressions of other children. Facial EMG activity to the presentation of dynamic emotional faces was recorded from the corrugator, zygomaticus, frontalis and depressor muscle in sixty-one healthy participants aged 6-7years. Results showed that the presentation of angry faces was associated with corrugator activation and zygomaticus relaxation, happy faces with an increase in zygomaticus and a decrease in corrugator activation, fearful faces with frontalis activation, and sad faces with a combination of corrugator and frontalis activation. This study demonstrates the feasibility of measuring facial EMG response to emotional facial expressions in 6-7year old children.     

Impact of total sleep deprivation and related mood changes on approach-avoidance decisions to threat-related facial displays

Study ObjectivesTotal sleep deprivation is known to have significant detrimental effects on cognitive and socio-emotional functioning. Nonetheless, the mechanisms by which total sleep loss disturbs decision-making in social contexts are poorly understood. Here, we investigated the impact of total sleep deprivation on approach/avoidance decisions when faced with threatening individuals, as well as the potential moderating role of sleep-related mood changes.MethodsParticipants (n = 34) made spontaneous approach/avoidance decisions in the presence of task-irrelevant angry or fearful individuals, while rested or totally sleep deprived (27 h of continuous wakefulness). Sleep-related changes in mood and sustained attention were assessed using the Positive and Negative Affective Scale and the psychomotor vigilance task, respectively.ResultsRested participants avoided both fearful and angry individuals, with stronger avoidance for angry individuals, in line with previous results. On the contrary, totally sleep deprived participants favored neither approach nor avoidance of fearful individuals, while they still comparably avoided angry individuals. Drift-diffusion models showed that this effect was accounted for by the fact that total sleep deprivation reduced value-based evidence accumulation toward avoidance during decision making. Finally, the reduction of positive mood after total sleep deprivation positively correlated with the reduction of fearful display avoidance. Importantly, this correlation was not mediated by a sleep-related reduction in sustained attention.ConclusionsAll together, these findings support the underestimated role of positive mood-state alterations caused by total sleep loss on approach/avoidance decisions when facing ambiguous socio-emotional displays, such as fear.     

Reactions to facial expressions: effects of social context and speech anxiety on responses to neutral, anger, and joy expressions

Male and female participants (n=19) high or low in speech fear viewed pictures of faces posed in anger, neutral, and joyful expressions for 8s each. Zygomaticus major and corrugator supercilii EMG, skin conductance, and heart rate were measured during picture viewing, and subjective ratings were made after each picture. Compared to anger expressions, joy expressions were responded to with greater zygomatic EMG, less corrugator EMG, and greater heart rate and skin conductance. Physiological response to neutral expressions was similar to response to anger expressions. Expressions posed by women were responded to physiologically more negatively than expressions posed by men. More fearful participants exhibited more negative and less positive facial expressions, and skin conductance responses suggesting greater attention when viewing negative expressions. Results suggest that reactions to facial expressions are influenced by social context, and are not simple mimicry.     

Silicone derivatives for contact lenses: Functionalization,chemical characterization,and cell compatibility assessment

Epoxy ring-opening functionalization of polymers at random sites along chains with various chemical groups has been demonstrated. The reaction is performed in an aqueous solution under mild conditions in order to minimize degradation of the macromolecular chains. Silicone lenses made of copolymers with epoxy side chains were functionalized with 4-hydroxybutyric acid, sodium salt. The carboxylated silicone derivatives were characterized by ESCA and radiotracers. A mean value of 30% reaction yield was concluded, based upon data from both methods; nevertheless, the latter can be improved up to 50% or more if the conditions of preparation of the epoxydized silicone lenses are optimized. Derivatized silicones were coated in the wells of culture plates to evaluate the cell compatibility of these new polymers with a fibroblast cell line (McCoy's). No cellular toxicity was observed.     

Temporal-spatial expressions of interleukin-4, interleukin-10, and interleukin-13 in the brains of C57BL/6 and BALB/c mice infected with Angiostrongylus cantonensis: An immunohistochemical study

BackgroundAngiostrongylus cantonensis is an important etiologic agent of eosinophilic meningitis and/or eosinophilic meningoencephalitis in humans. Th2 responses have been considered to be predominant in non-permissive hosts. However, changes of cytokines in the central nervous system of the host remain unclear. The present study was conducted to determine the temporal-spatial expressions of IL-4, IL-10, and IL-13 in the brains of infected C57BL/6 and BALB/c mice by immunohistochemistry.MethodsAfter infecting each mouse with 25 third-stage larvae (L3), brain specimens were collected on day 7 and day 28 post-infection. Each specimen was cut into five sections and stained with corresponding antibodies of the three cytokines.ResultsIn infected C57BL/6 mice, high IL-4 expressions were found in the isocortex, IL-10 in the isocortex, olfactory area, hippocampus, cerebral nuclei, hypothalamus, cerebellum nuclei, and medulla, and IL-13 in the isocortex and cerebellum. In infected BALB/c mice, IL-4 and IL-10 were highly expressed in the isocortex, olfactory areas, cerebral nuclei, hypothalamus, and cerebellum nuclei and IL-13 in the thalamus and hypothalamus. High levels of the cytokines were usually detected in on day 7 in BALB/c mice and day 28 in C57BL/6 mice.ConclusionThe special temporal-spatial expression changes of these three cytokines in the infected mouse brain may explain the differences in the survival and the time of occurrence of immune responses in the hosts after A. cantonensis infection.     

Automatic polyp detection and measurement with computed tomographic colonography: A phantom study

Purpose

The purpose of this study is to assess the performance of computer-aided detection (CAD) software in detecting and measuring polyps for CT Colonography, based on an in vitro phantom study.

Material and methods

A colon phantom was constructed with a PVC pipe of 3.8 cm diameter. Nine simulated polyps of various sizes (3.2mm-25.4mm) were affixed inside the phantom that was placed in a water bath. The phantom was scanned on a 64-slice CT scanner with tube voltage of 120 kV and current of 205 mAs. Two separate scans were performed, with different slice thickness and reconstruction interval. The first scan (thin) had a slice thickness of 1mm and reconstruction interval 0.5mm. The second scan (thick) had a slice thickness of 2mm and reconstruction interval of 1mm. Images from both scans were processed using CT Colonography software that automatically segments the colon phantom and applies CAD that automatically highlights and provides the size (maximum and minimum diameters, volume) of each polyp. Two readers independently measured each polyp (two orthogonal diameters) using both 2D and 3D views. Readers’ manual measurements (diameters) and automatic measurements from CAD (diameters and volume) were compared to actual polyp sizes as measured by mechanical calipers.

Results

All polyps except the smallest (3.2mm) were detected by CAD. CAD achieved 100% sensitivity in detecting polyps ≥6mm. Mean errors in CAD automated volume measurements for thin and thick slice scans were 8.7% and 6.8%, respectively. Almost all CAD and manual readers’ 3D measurements overestimated the size of polyps to variable extent. Both over- and underestimation of polyp sizes were observed in the readers’ manual 2D measurements. Overall, Reader 1 (expert) had smaller mean error than Reader 2 (non-expert).

Conclusion

CAD provided accurate size measurements for all polyps, and results were comparable to the two readers'' manual measurements     

Automatic brain response to facial emotion as a function of implicitly and explicitly measured extraversion

Extraversion/introversion is a basic dimension of personality that describes individual differences in social behavior and sensory sensitivity. Previous neuroimaging research exclusively relied on self reports for assessing personality traits. In recent years, implicit measures of personality have been developed that aim at assessing the implicit self-concept of personality and complement self report instruments which are thought to measure aspects of the explicit self-concept of personality. In the present study functional magnetic resonance imaging was used to examine automatic brain reactivity to facial expression as a function of both implicitly and explicitly measured extraversion in 30 healthy women. Sad, happy, and neutral faces were presented for 33 ms masked by neutral faces beside a no face control condition. Subjects evaluated the briefly shown neutral mask faces. The Implicit Association Test (IAT) and the NEO Five-Factor Inventory (NEO-FFI) were applied as measures of extraversion which were not correlated in our sample. IAT extraversion was negatively correlated with automatic reactivity of the caudate head, thalamus, and inferior frontal cortex to sad faces. NEO-FFI extraversion was negatively correlated with response of the inferior frontal cortex and putamen to sad faces. For masked happy faces, an inverse correlation of the IAT effect for extraversion with activation of the caudate head and superior parietal lobule was observed. NEO-FFI extraversion was inversely correlated with the response of the thalamus to happy faces. Neither NEO-FFI extraversion nor IAT effect were significantly related to brain response to masked neutral faces (compared to the no face condition). Taken together, a specific heightened responsivity of the fronto-striatal-thalamic circuit to facial emotions which are arousing stimuli might underlie introverts' preference for avoiding social interactions. Research on the neurobiology of extraversion could benefit from the application of implicit in addition to explicit measurement instruments when automatic neural responses are investigated.