Motor Commands of Facial Expressions: The Bereitschaftspotential of Posed Smiles (original) (raw)
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Automatic Face & Gesture …, 2008
Facial expressions are part of emotional reactions. However, humans can voluntarily pose a specific emotional expression without having the corresponding underlying feeling, or voluntarily modify (e.g. reduce or enhance) their spontaneous expression in reaction to an emotional event. Few studies have attempted to distinguish these different processes at the level of the central nervous system (CNS), even though spontaneous and voluntary facial expressions are long thought to rely upon distinct neural circuitries. Here, we review the neural bases of spontaneous and voluntary facial expressions, report the results of a first study assessing the Bereitschaftspotential (BP) before voluntary smiles, and outline a combined EEG/EMG approach for investigating facial expressions at the level of the CNS.
Similar facial electromyographic responses to faces, voices, and body expressions
NeuroReport, 2007
Observing facial expressions automatically prompts imitation, as can be seen with facial electromyography. To investigate whether this reaction is driven by automatic mimicry or by recognition of the emotion displayed we recorded electromyograph responses to presentations of facial expressions, face^voice combinations and bodily expressions, which resulted from happy and fearful stimuli. We observed emotion-speci¢c facial muscle activity (zygomaticus for happiness, corrugator for fear) for all three stimulus categories. This indicates that spontaneous facial expression is more akin to an emotional reaction than to facial mimicry and imitation of the seen face stimulus. We suggest that seeing a facial expression, an emotional body expression or hearing an emotional tone of voice all activate the a¡ect program corresponding to the emotion displayed. NeuroReport 18:369^372
Journal of Nonverbal …, 1989
Twenty subjects judged 80 video segments containing brief episodes of smiling behavior for expression intensity and happiness of the stimulus person. The video records were produced under instructions to (a) pose, (b) experience a happy feeling or (c) to both experience and show a happy feeling. An analysis of the integrated facial electromyogram (EMG), recorded over four muscle regions (zygomaticus major, depressor anguli oris, corrugator supercilii, and masseter), showed that judgments of happiness and of intensity of expression could be predicted in a multiple regression analysis (multiple R = .64 for perceived happiness and .79 for perceived expression intensity). The perception of happiness was affected by EMG activity in regions other than zygomaticus major. The use of parameters other than the mean of the integrated EMG, namely variance, skewness, kurtosis and properties of the amplitude distributions across time, provided accurate classification of the elicitation conditions (pose happiness versus experience happiness) in a discriminant analysis. For the discrimination of posed and felt smiles variables describing aspects of facial activity in the temporal domain were more useful than any of the other measures. It is suggested that facial EMG can be a useful tool in the analysis of both the encoding and decoding of expressive behavior. The results indicate the advantage of using multiple-site EMG recordings as weil as of using amplitude and temporal characteristics of the facial EMG measures.
When you smile, the world smiles at you: ERP evidence for self-expression effects on face processing
Social cognitive and affective neuroscience, 2015
Current models of emotion simulation propose that intentionally posing a facial expression can change one's subjective feelings, which in turn influences the processing of visual input. However, the underlying neural mechanism whereby one's facial emotion modulates the visual cortical responses to other's facial expressions remains unknown. To understand how one's facial expression affects visual processing, we measured participants' visual evoked potentials (VEPs) during a facial emotion judgment task of positive and neutral faces. To control for the effects of facial muscles on VEPs, we asked participants to smile (adopting an expression of happiness), to purse their lips (incompatible with smiling) or to pose with a neutral face, in separate blocks. Results showed that the smiling expression modulates face-specific visual processing components (N170/vertex positive potential) to watching other facial expressions. Specifically, when making a happy expression, n...
Journal of Personality and Social Psychology, 1986
Physiological measures have traditionally been viewed in social psychology as useful only in assessing general arousal and therefore as incapable of distinguishing between positive and negative affective states. This view is challenged in the present report. Sixteen subjects in a pilot study were exposed briefly to slides and tones that were mildly to moderately evocative of positive and negative affect. Facial electromyographic (EMG) activity differentiated both the valence and intensity of the affective reaction. Moreover, independent judges were unable to determine from viewing videotapes of the subjects' facial displays whether a positive or negative stimulus had been presented or whether a mildly or moderately intense stimulus had been presented. In the full experiment, 28 subjects briefly viewed slides of scenes that were mildly to moderately evocative of positive and negative affect. Again, EMG activity over the brow (enrrugator supercilia), eye (orbieularis oculi), and cheek (zygomatic major) muscle regions differentiated the pleasantness and intensity of individuals' affective reactions to the visual stimuli even though visual inspection of the videotapes again indicated that expressions of emotion were not apparent. These results suggest that gradients of EMG activity over the muscles of facial expression can provide objective and continuous probes of affective processes that are too subtle or fleeting to evoke expressions observable under normal conditions of social interaction.
NeuroImage, 2015
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 f...
Face-specific event-related potential in humans is independent from facial expression
International Journal of Psychophysiology, 2002
A face-specific brain EEG potential at approximately 160 ms after stimulus presentation has recently been described by various research groups. Most of these studies analysed this face-specific brain potential using smiling faces as stimuli. In electrophysiological studies, however, differences in amplitude due to the emotional valence of the stimuli were described as early as 100 ms after stimulus presentation. In order to investigate the effect of facial expressions with different emotional content on face-specific brain EEG potentials, event-related potentials (ERPs) to faces with sad, happy and neutral expressions were compared to ERPs elicited with buildings in 16 healthy subjects. A facespecific potential at vertex approximately 160 ms after stimulus presentation has been verified in the present study. No significant differences in latency or amplitude of this component were found for different facial expressions. ᮊ
Erps Evoked by Viewing Facial Movements
Cognitive Neuropsychology, 2000
Human neuroimaging and event-related potential (ERP) studies suggest that ventral and lateral temporo-occipital cortex is sensitive to static faces and face parts. Recent fMRI data also show activation by facial movements. In this study we recorded from 22 posterior scalp locations in 20 normal righthanded males to assess ERPs evoked by viewing: (1) moving eyes and mouths in the context of a face; (2) moving and static eyes with and without facial context. N170 and P350 peak amplitude and latency data were analysed. N170 is an ERP previously shown to be preferentially responsive to face and eye stimuli, and P350 immediately follows N170. Major results were: (1) N170 was significantly larger over the bilateral temporal scalp to viewing opening mouths relative to closing mouths, and to eye aversion relative to eyes gazing at the observer; (2) at a focal region over the right inferior temporal scalp, N170 was significantly earlier to mouth opening relative to closing, and to eye aversion relative to eyes gazing at the observer; (3) the focal ERP effect of eye aversion occurred independent of facial context; (4) these differences cannot be attributable to movement per se, as they did not occur in a control condition in which checks moved in comparable areas of the visual field; (5) isolated static eyes produced N170s that were not significantly different from N170s to static full faces over the right inferior temporal scalp, unlike in the left hemisphere where face N170s were significantly larger than eye N170s; (6) unlike N170, P350 exhibited nonspecific changes as a function of stimulus movement. These results suggest that: (1) bilateral temporal cortex forms part of a system sensitive to biological motion, of which facial movements form an important subset; (2) there may be a specialised system for facial gesture analysis that provides input for neuronal circuitry dealing with social attention and the actions of others.
Timing and voluntary suppression of facial mimicry to smiling faces in a Go/NoGo task--An EMG study
Biological psychology, 2010
Results obtained with a novel emotional Go/NoGo task allowing the investigation of facial mimicry (FM) during the production and inhibition of voluntary smiles are discussed. Healthy participants were asked to smile rapidly to happy faces and maintain a neutral expression to neutral faces, or the reverse. Replicating and extending previous results, happy faces induced FM, as shown by stronger and faster zygomatic activation to happy than neutral faces in Go trials, and a greater number of false alarms to happy faces in NoGo trials. Facial mimicry effects remained present during participants’ active inhibition of facial movement. Latencies of FM were short with 126–250 ms in Go trials, and 251–375 ms in NoGo trials. The utility of the Go/NoGo task, which allows the assessment of response inhibition in the domain of facial expression by installing strong prepotent motor responses via short stimulus presentation times and a great number of Go trials, is discussed.
Eye contact with neutral and smiling faces: effects on autonomic responses and frontal EEG asymmetry
Frontiers in human neuroscience, 2012
In our previous studies we have shown that seeing another person "live" with a direct vs. averted gaze results in enhanced skin conductance responses (SCRs) indicating autonomic arousal and in greater relative left-sided frontal activity in the electroencephalography (asymmetry in the alpha-band power), associated with approach motivation. In our studies, however, the stimulus persons had a neutral expression. In real-life social interaction, eye contact is often associated with a smile, which is another signal of the sender's approach-related motivation. A smile could, therefore, enhance the affective-motivational responses to eye contact. In the present study, we investigated whether the facial expression (neutral vs. social smile) would modulate autonomic arousal and frontal EEG alpha-band asymmetry to seeing a direct vs. an averted gaze in faces presented "live" through a liquid crystal (LC) shutter. The results showed that the SCRs were greater for the d...