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PubMed2004

Extending the global workspace theory to emotion: phenomenality without access.

Recent accounts on the global workspace theory suggest that consciousness involves transient formations of functional connections in thalamo-cortico-cortical networks. The level of connectivity in these networks is argued to determine the state of consciousness. Emotions are suggested to play a role in shaping consciousness, but their involvement in the global workspace theory remains elusive. In the present study, the role of emotion in the neural workspace theory of consciousness was scrutinized by investigating, whether unconscious (masked) and conscious (unmasked) display of emotional compared to neutral facial expressions would differentially modulate EEG coherence. EEG coherence was measured by means of computing an average EEG coherence value between the frontal, parietal, and midline scalp sites. Objective awareness checks evidenced that conscious identification of the masked facial expressions was precluded. Analyses revealed reductions in EEG coherence in the lower frequency range for the masked as compared to unmasked neutral facial expressions. Crucially, a decline in EEG coherence was not observed for the emotional facial expressions. In other words, the level of EEG coherence did apparently vary as a function of awareness, but not when emotion was involved. The current finding suggests that EEG coherence is modulated by unconscious emotional processes, which extends common views on the global workspace architecture of consciousness.

Adult↗
PubMed2004

Perceptual biases for multimodal cues in chimpanzee (Pan troglodytes) affect recognition.

The ability of organisms to discriminate social signals, such as affective displays, using different sensory modalities is important for social communication. However, a major problem for understanding the evolution and integration of multimodal signals is determining how humans and animals attend to different sensory modalities, and these different modalities contribute to the perception and categorization of social signals. Using a matching-to-sample procedure, chimpanzees discriminated videos of conspecifics' facial expressions that contained only auditory or only visual cues by selecting one of two facial expression photographs that matched the expression category represented by the sample. Other videos were edited to contain incongruent sensory cues, i.e., visual features of one expression but auditory features of another. In these cases, subjects were free to select the expression that matched either the auditory or visual modality, whichever was more salient for that expression type. Results showed that chimpanzees were able to discriminate facial expressions using only auditory or visual cues, and when these modalities were mixed. However, in these latter trials, depending on the expression category, clear preferences for either the visual or auditory modality emerged. Pant-hoots and play faces were discriminated preferentially using the auditory modality, while screams were discriminated preferentially using the visual modality. Therefore, depending on the type of expressive display, the auditory and visual modalities were differentially salient in ways that appear consistent with the ethological importance of that display's social function.

Acoustic Stimulation↗
PubMed2006

Reproducibility of a method for analysis of morphological changes in perioral soft tissue in children using video cameras.

The purpose of the present study was to determine the appropriate reference facial expression and to examine the reproducibility of our system using two commercially available video cameras in consideration of functional diagnosis of perioral muscles. The following items were investigated: 1) influence of forward and backward movements and the experiment sequence from measurement to analysis, 2) usefulness of head fixation by a restraining device during video recording for evaluation of morphological changes in facial expression, 3) conditions for establishment of reference points for determination of movements of perioral soft tissue, and 4) reproducibility of perioral soft tissue movements as assessed by changes in landmarks. The results of this study showed that accurate static and dynamic evaluation of perioral soft tissue is possible by using our method of video recording with the subject's head restrained and our method of analysis. The results also showed that centric occlusion of the most appropriate reference facial expression as for measurement of perioral soft tissue movements and that protrusion of the lips and lateral extension of the angel of the mouth are facial expressions with high degrees of reproducibility.

Child, Preschool↗
PubMed2003

Face-selective processing and the effect of pleasant and unpleasant emotional expressions on ERP correlates.

Previous studies have revealed that decoding of facial-expressions starts very early in the brain ( approximately 180 ms post-stimulus) and might be processed separately from the basic stage of face perception. In order to explore brain potentials (ERPs) related to decoding of facial-expressions and the effect of emotional valence of the stimulus, we analyzed 18 normal subjects. Faces with five basic emotional expressions (fear, anger, surprise, happiness, sadness) and neutral stimulus were presented in random order. The results demonstrated that an emotional face elicited a negative peak at approximately 230 ms (N230), distributed mainly over the posterior site for each emotion. The electrophysiological activity observed may represent specific cognitive processing underlying the decoding of emotional facial-expressions. Nevertheless, differences in peak amplitude were observed for high-arousal negative expressions compared with positive (happiness) and low-arousal expressions (sadness). N230 amplitude increased in response to anger, fear and surprise, suggesting that subjects' ERP variations are affected by experienced emotional intensity, related to arousal and unpleasant value of the stimulus.

Adult↗
PubMed2006

Aging and visual search: automatic and controlled attentional bias to threat faces.

Using a visual search paradigm, we investigated how age affected attentional bias to emotional facial expressions. In Experiments 1 and 2, participants searched for a discrepant facial expression in a matrix of otherwise homogeneous faces. Both younger and older adults showed a more effective search when the discrepant face was angry rather than happy or neutral. However, when the angry faces served as non-target distractors, younger adults' search was less effective than happy or neutral distractor conditions. In contrast, older adults showed a more efficient search with angry distractors than happy or neutral distractors, indicating that older adults were better able to inhibit angry facial expressions. In Experiment 3, we found that even a top-down search goal could not override the angry face superiority effect in guiding attention. In addition, RT distribution analyses supported that both younger and older adults performed the top-down angry face search qualitatively differently from the top-down happy face search. The current research indicates that threat face processing involves automatic attentional shift and a controlled attentional process. The current results suggest that age only influenced the controlled attentional process.

Adult↗
PubMed2003

Neural correlates of the automatic processing of threat facial signals.

The present study examined whether automaticity, defined here as independence from attentional modulation, is a fundamental principle of the neural systems specialized for processing social signals of environmental threat. Attention was focused on either scenes or faces presented in a single overlapping display. Facial expressions were neutral, fearful, or disgusted. Amygdala responses to facial expressions of fear, a signifier of potential physical attack, were not reduced with reduced attention to faces. In contrast, anterior insular responses to facial expressions of disgust, a signifier of potential physical contamination, were reduced with reduced attention. However, reduced attention enhanced the amygdala response to disgust expressions; this enhanced amygdala response to disgust correlated with the magnitude of attentional reduction in the anterior insular response to disgust. These results suggest that automaticity is not fundamental to the processing of all facial signals of threat, but is unique to amygdala processing of fear. Furthermore, amygdala processing of fear was not entirely automatic, coming at the expense of specificity of response. Amygdala processing is thus specific to fear only during attended processing, when cortical processing is undiminished, and more broadly tuned to threat during unattended processing, when cortical processing is diminished.

Adolescent↗
PubMed2003

Seeing fearful body expressions activates the fusiform cortex and amygdala.

Darwin's evolutionary approach to organisms' emotional states attributes a prominent role to expressions of emotion in whole-body actions. Researchers in social psychology [1,2] and human development [3] have long emphasized the fact that emotional states are expressed through body movement, but cognitive neuroscientists have almost exclusively considered isolated facial expressions (for review, see [4]). Here we used high-field fMRI to determine the underlying neural mechanisms of perception of body expression of emotion. Subjects were presented with short blocks of body expressions of fear alternating with short blocks of emotionally neutral meaningful body gestures. All images had internal facial features blurred out to avoid confounds due to a face or facial expression. We show that exposure to body expressions of fear, as opposed to neutral body postures, activates the fusiform gyrus and the amygdala. The fact that these two areas have previously been associated with the processing of faces and facial expressions [5-8] suggests synergies between facial and body-action expressions of emotion. Our findings open a new area of investigation of the role of body expressions of emotion in adaptive behavior as well as the relation between processes of emotion recognition in the face and in the body.

Amygdala↗
PubMed2005

Stability of amygdala BOLD response to fearful faces over multiple scan sessions.

We used fMRI to examine amygdala activation in response to fearful facial expressions, measured over multiple scanning sessions. 15 human subjects underwent three scanning sessions, at 0, 2 and 8 weeks. During each session, functional brain images centered about the amygdala were acquired continuously while participants were shown alternating blocks of fearful, neutral and happy facial expressions. Intraclass correlation coefficients calculated across the sessions indicated stability of response in left amygdala to fearful faces (as a change from baseline), but considerably less left amygdala stability in responses to neutral expressions and for fear versus neutral contrasts. The results demonstrate that the measurement of fMRI BOLD responses in amygdala to fearful facial expressions might be usefully employed as an index of amygdala reactivity over extended periods. While signal change to fearful facial expressions appears robust, the experimental design employed here has yielded variable responsivity within baseline or comparison conditions. Future studies might manipulate the experimental design to either amplify or attenuate this variability, according to the goals of the research.

Adult↗
PubMed2005

Being with virtual others: Neural correlates of social interaction.

To characterize the neural correlates of being personally involved in social interaction as opposed to being a passive observer of social interaction between others we performed an fMRI study in which participants were gazed at by virtual characters (ME) or observed them looking at someone else (OTHER). In dynamic animations virtual characters then showed socially relevant facial expressions as they would appear in greeting and approach situations (SOC) or arbitrary facial movements (ARB). Differential neural activity associated with ME>OTHER was located in anterior medial prefrontal cortex in contrast to the precuneus for OTHER>ME. Perception of socially relevant facial expressions (SOC>ARB) led to differentially increased neural activity in ventral medial prefrontal cortex. Perception of arbitrary facial movements (ARB>SOC) differentially activated the middle temporal gyrus. The results, thus, show that activation of medial prefrontal cortex underlies both the perception of social communication indicated by facial expressions and the feeling of personal involvement indicated by eye gaze. Our data also demonstrate that distinct regions of medial prefrontal cortex contribute differentially to social cognition: whereas the ventral medial prefrontal cortex is recruited during the analysis of social content as accessible in interactionally relevant mimic gestures, differential activation of a more dorsal part of medial prefrontal cortex subserves the detection of self-relevance and may thus establish an intersubjective context in which communicative signals are evaluated.

Adult↗
PubMed1986

Acute pain response in infants: a multidimensional description.

Fourteen infants who were undergoing routine immunization were studied from a multidimensional perspective. The measures used were heart rate, crying, body movement/posturing, and voice spectrographs. There was wide variability between infants on the measures, especially on the cry spectrographs, although facial expression was consistent across infants. The pattern that did emerge was characterized by an initial response: a drop in heart rate, a long, high pitched cry followed by a period of apnea, rigidity of the torso and limbs, and a facial expression of pain. This was followed by a sharp increase in heart rate, lower pitched, but dysphonated cries, less body rigidity, but still facial expression was of pain. Finally, in the second half of the minute's response, heart rate remained elevated, cries were lower pitched, more rhythmic, with a rising-falling pattern, and were mostly phonated, and body posturing returned to normal. Those faces that could be viewed also were returning to the at rest configuration. It was suggested that facial expression may be the most consistent across-infant indicator of pain at this point in time.

Acute Disease↗
PubMed2003

Modulation of focused attention by faces expressing emotion: evidence from flanker tasks.

Three experiments evaluated whether facial expression can modulate the allocation of focused attention. Identification of emotionally expressive target faces was typically faster when they were flanked by identical (compatible) faces compared with when they were flanked by different (incompatible) faces. This flanker compatibility effect was significantly smaller when target faces expressed negative compared with positive emotion (see Experiment 1A); however, when the faces were altered to disrupt emotional expression, yet retain feature differences, equal flanker compatibility effects were observed (see Experiment 1B). The flanker-compatibility effect was also found to be smaller for negative target faces compared compatibility with neutral target faces, and for both negative and neutral target faces compared with positive target faces (see Experiment 2). These results suggest that the constriction of attention is influenced by facial expressions of emotion.

Adult↗
PubMed2000

Recognizing emotion in faces: developmental effects of child abuse and neglect.

The contributions to the recognition of emotional signals of (a) experience and learning versus (b) internal predispositions are difficult to investigate because children are virtually always exposed to complex emotional experiences from birth. The recognition of emotion among physically abused and physically neglected preschoolers was assessed in order to examine the effects of atypical experience on emotional development. In Experiment 1, children matched a facial expression to an emotional situation. Neglected children had more difficulty discriminating emotional expressions than did control or physically abused children. Physically abused children displayed a response bias for angry facial expressions. In Experiment 2, children rated the similarity of facial expressions. Control children viewed discrete emotions as dissimilar, neglected children saw fewer distinctions between emotions, and physically abused children showed the most variance across emotions. These results suggest that to the extent that children's experience with the world varies, so too will their interpretation and understanding of emotional signals.

Attention↗
PubMed2006

Emotional face processing deficit in schizophrenia: A replication study in a South African Xhosa population.

Schizophrenia is associated with a deficit in the recognition of negative emotions from facial expressions. The present study examined the universality of this finding by studying facial expression recognition in African Xhosa population. Forty-four Xhosa patients with schizophrenia and forty healthy controls were tested with a computerized task requiring rapid perceptual discrimination of matched positive (i.e. happy), negative (i.e. angry), and neutral faces. Patients were equally accurate as controls in recognizing happy faces but showed a marked impairment in recognition of angry faces. The impairment was particularly pronounced for high-intensity (open-mouth) angry faces. Patients also exhibited more false happy and angry responses to neutral faces than controls. No correlation between level of education or illness duration and emotion recognition was found but the deficit in the recognition of negative emotions was more pronounced in familial compared to non-familial cases of schizophrenia. These findings suggest that the deficit in the recognition of negative facial expressions may constitute a universal neurocognitive marker of schizophrenia.

Adult↗
PubMed2004

Differential impairments of facial affect recognition in schizophrenia subtypes and major depression.

The goal of this study was to assess facial affect recognition abilities in subjects with various schizophrenia subtypes and subjects with major depression. A total of six disorganized, 21 paranoid and 18 residual subjects with schizophrenia (DSM-IV criteria) were compared with 21 subjects with major depression (DSM-IV criteria) and 30 matched healthy control subjects. Two experimental tasks requiring the sorting and rating of emotional facial expressions were applied. Disorganized and paranoid subjects showed strong impairments in the sorting of emotional facial expressions. Depressive subjects displayed only minor deficits, and residual subjects were unimpaired. Subjects with disorganized schizophrenia rated emotional facial expressions as more aroused, and depressive subjects rated them as less aroused, than the other study groups. Our study demonstrates strong deficits in facial affect recognition in subjects with schizophrenia and pronounced disorganized or psychotic symptoms. Deficits in facial affect recognition are specific to schizophrenia. They may be considered as a state marker of schizophrenia.

Adult↗
PubMed1985

The role of the face in human emotion: first system or one of many?

Evidence relating to the hypothesis on facial feedback which ties the experience of discrete emotions to feedback from innately patterned facial expressions is discussed. Strong evidence is deduced for a more general form of the hypothesis, but the requirements of necessity and sufficiency representing the strictest form are only satisfied within narrow limits of experimental manipulations which are not common to all investigations. Evidence is deemed to support a relationship between facial expression and emotion, but facial expression is regarded as one of many systems and cannot be assigned an exclusive role (either as first system or as necessary system).

Autonomic Nervous System↗
PubMed2006

What is adapted in face adaptation? The neural representations of expression in the human visual system.

The neural representation of facial expression within the human visual system is not well defined. Using an adaptation paradigm, we examined aftereffects on expression perception produced by various stimuli. Adapting to a face, which was used to create morphs between two expressions, substantially biased expression perception within the morphed faces away from the adapting expression. This adaptation was not based on low-level image properties, as a different image of the same person displaying that expression produced equally robust aftereffects. Smaller but significant aftereffects were generated by images of different individuals, irrespective of gender. Non-face visual, auditory, or verbal representations of emotion did not generate significant aftereffects. These results suggest that adaptation affects at least two neural representations of expression: one specific to the individual (not the image), and one that represents expression across different facial identities. The identity-independent aftereffect suggests the existence of a 'visual semantic' for facial expression in the human visual system.

Adaptation, Physiological↗
PubMed2005

Minimum effective dose of midazolam for sedation of mechanically ventilated neonates.

OBJECTIVE: To determine the minimal effective dose (MED) of intravenous midazolam, required for appropriate sedation in 95% of patients, 1 h after drug administration. METHODS: A double-blind dose-finding study using the continual reassessment method, a Bayesian sequential design. Twenty-three newborn infants hospitalized in intensive care unit participated. Inclusion criteria were: (i) post-natal age <28 days, (ii) gestational age >33 weeks, (iii) intubation and ventilatory support required for respiratory distress syndrome, (iv) need for sedation (i.e. one of the six following criteria: agitation or grimacing or crying facial expression before tracheal suctioning, agitation or grimacing or crying facial expression during tracheal suctioning). Each neonate was allocated to a loading dose, ranging from 75 to 200 microg/kg, and a maintenance dose ranging from 37.5 to 100 microg/kg/h. RESULTS: The primary endpoint was the level of sedation 1 h after the onset of infusion. The sedation procedure was classified as a success if all the following clinical criteria were met: no agitation, no grimacing and no crying facial expression before as well as during tracheal suctioning. Based on the 23 patients, the final estimated probability of success was 76.9% (95% credibility interval: 56.6-91.4%) for the 200 microg/kg loading dose. no significant adverse effect was observed. CONCLUSIONS: Continual reassessment is a new approach, suitable for dose-finding study in neonates. this method overcomes some of the ethical, statistical and practical problems associated with this population. Using this method, the MED was estimated to be the 200 mug/kg loading dose of midazolam.

Dose-Response Relationship, Drug↗
PubMed1992

The effect of alcohol on emotional response to a social stressor.

Social drinkers were administered either an alcoholic, placebo or no-alcohol control beverage. Subjects were next informed that they were to give a self-disclosing speech about their body and physical appearance. Subjects' heart rate and videotapes of their facial expression were recorded during this instruction. Facial reactions to the stressor were analyzed using a system based on the Maximally Discriminative Facial Coding System (Izard, 1979). Subjects who were intoxicated showed significantly less negative emotion, as measured by the facial expression analysis, than those subjects consuming either the control or placebo beverage. We attribute this effect of alcohol to its actions on subjects' appraisal of anxiety-inducing information.

Adult↗