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International audience; Accumulating evidence indicates that the peripersonal space (PPS) constitutes a privileged area for efficient processing of proximal stimuli, allowing to flexibly adapt our behavior both to the physical and social environment. Whether and how behavioral and physiological signatures of PPS relate to each other in emotional contexts remains, though, elusive. Here, we addressed this question by having participants to discriminate male from female faces depicting different emotions (happiness, anger or neutral) and presented at different distances (50 cm-300 cm) while we measured the reaction time and accuracy of their responses, as well as pupillary diameter, heart rate and heart rate variability. Results showed facilitation of participants' performances (i.e., faster response time) when faces were presented close compared to far from the participants, even when controlling for retinal size across distances. These behavioral effects were accompanied by significant modulation of participants' physiological indexes when faces were presented in PPS. Interestingly, both PPS representation and physiological signals were affected by features of the seen faces such as the emotional valence, its sex and the participants' sex, revealing the profound impact of social context onto the autonomic state and behavior within PPS. Together, these findings suggest that both external and internal signals contribute in shaping PPS representation.

Humans are expert at recognizing facial features whether they are variable (emotions) or unchangeable (gender). Because of its huge communicative value, pain might be detected faster in faces than unchangeable features. Based on this assumption, we aimed to find a presentation time that enables subliminal discrimination of pain facial expression without permitting gender discrimination. For 80 individuals, we compared the time needed (50, 100, 150, or 200 milliseconds) to discriminate masked static pain faces among anger and neutral faces with the time needed to discriminate male from female faces. Whether these discriminations were associated with conscious reportability was tested with confidence measures on 40 other individuals. The results showed that, at 100 milliseconds, 75% of participants discriminated pain above chance level, whereas only 20% of participants discriminated the gender. Moreover, this pain discrimination appeared to be subliminal. This priority of pain over gender might exist because, even if pain faces are complex stimuli encoding both the sensory and the affective component of pain, they signal a danger. This supports the evolution theory relating to the necessity of quickly reading aversive emotions to ensure survival but might also be at the basis of altruistic behavior such as help and compassion.This study shows that pain facial expression can be processed subliminally after brief presentation times, which might be helpful for critical emergency situations in clinical settings.

International audience; Human beings are social animals. This ability to live together is ensured by cognitive functions, the neuroanatomical bases of which are starting to be unraveled by MRI-based studies. The regions and network engaged in this process are known as the "social brain ". The core of this network is the superior temporal sulcus (STS), which integrates sensory and emotional inputs. Modeling studies of healthy volunteers have shown the role of the STS.in recognizing others as biological beings, as well as facial and eye-gaze recognition, intentionality and emotions. This cognitive capacity has been described as the "theory of mind ". Pathological models such as autism, in which the main clinical abnormality is altered social abilities and communication, have confirmed the role of the STS in the social brain. Conceptualisation of this empathic capacity has been described as "meta cognition ", which forms the basis of human social organizationand culture.

International audience; Deep brain stimulation of the subthalamic nucleus (DBS) is a widely used surgical technique to suppress motor symptoms in Parkinson's disease (PD), and as such improves patients' quality of life. However, DBS may produce emotional disorders such as a reduced ability to recognize emotional facial expressions (EFE). Previous studies have not considered the fact that DBS and l-dopa medication can have differential, common, or complementary consequences on EFE processing. A thorough way of investigating the effect of DBS and l-dopa medication in greater detail is to compare patients' performances after surgery, with the two therapies either being administered ('on') or not administered ('off'). We therefore used a four-condition (l-dopa 'on'/DBS 'on', l-dopa 'on'/DBS 'off', l-dopa 'off'/DBS 'on', and l-dopa 'off'/DBS 'off') EFE recognition paradigm and compared implanted PD patients to healthy controls. The results confirmed those of previous studies, yielding a significant impairment in the detection of some facial expressions relative to controls. Disgust recognition was impaired when patients were 'off' l-dopa and 'on' DBS, and fear recognition impaired when 'off' of both therapies. More interestingly, the combined effect of both DBS and l-dopa administration seems much more beneficial for EFE recognition than the separate administration of each individual therapy. We discuss the implications of these findings in the light of the inverted U curve function that describes the differential effects of dopamine level on the right orbitofrontal cortex (OFC). We propose that, while l-dopa could "overdose" in dopamine the ventral stream of the OFC, DBS would compensate for this over-activation by decreasing OFC activity, thereby restoring the necessary OFC-amygdala interaction. Another finding is that, when collapsing over all treatment conditions, PD patients recognized more neutral faces than the matched controls, a result that concurs with embodiment theories.

International audience; Studies on emotional processing in Alzheimer's disease (AD) have reported abnormalities in emotional decoding. However, it remains unclear whether the impairment depends on a general cognitive decline that characterizes these patients or is an independent deficit. We conducted a comprehensive meta-analysis of existing studies that compared AD patients with age-matched healthy older adults (HOA) on measures of emotional decoding abilities. Our first goal was to quantify the magnitude of the AD patients' deficit. The second goal was to identify variables that may modulate the deficit, including emotional task design and participants' characteristics. The random-effects model analysis on 212 effect sizes indicated that AD patients showed significant impairment in emotional decoding abilities. This deficit is consistent regardless of the emotional task, stimuli, type of emotion considered, or disease severity. After we controlled for cognitive status, the emotional performance in AD patients was still poorer than that in HOA. The effect size of emotional performance was significantly lower when the cognitive status was considered than when it was not. Thus, our results suggest that impaired emotion processing in AD patients cannot be solely explained by the cognitive deficit. These findings provide evidence that progressive neuropathological changes characterizing the disease could affect emotional processing, which may suggest that clinicians should be sensitive to the emergence of impairments in emotional decoding. Further research that addresses the limitations of existing studies is needed to draw conclusions about methodological issues and the impact of the AD patient's depression symptoms on emotional decoding.

International audience; Whether food liking may be a risk factor of overconsumption and overweight/obesity remains a controversial issue. So far, most studies used subjective reports to assess consummatory behavior, approaches that might overlook subtle or implicit hedonic changes to sensory properties of foods. Therefore, we used a cue-exposure approach by recording different measures of hedonic processes (orofacial reactivity, self-rated pleasantness, food preference) in 6-11 years old overweight (n=20) and normal-weight (n=20) children. Children were exposed to the smell and sight of high and low-energy density food stimuli and to non-food stimuli during pre- and post-prandial states. Their facial and verbal responses were videotaped and parent's reports of children's eating styles and appetitive traits were collected using the Children's Eating Behavior Questionnaire (CEBQ). Results showed that orofacial reactivity, as an objective measure of anticipatory liking, was more discriminative than self reports, with overweight children displaying more lip sucking than normal-weight children when exposed to high energy food pictures and to food odorants. Orofacial reactivity to food cues was also associated with BMI and children's eating styles (food responsiveness, emotional overeating, and desire to drink). Finally, overweight children classified more frequently non-food odorants as members of the food category during the pre-prandial state than during the post-prandial state, suggesting a possible influence of affective/motivational bias on odor categorization. Our findings suggest that orofacial responsiveness may be relevant to assess the sensitivity to energy-dense food reward cues in overweight children and for signaling, as an index of anticipatory liking, a potential risk for the development of overweight/obesity.

Background: The aim of the present study was to assess the possibility of compensating early facial expression recognition impairments in amnestic Mild Cognitive Impairment (a-MCI) patients. Methods: Twelve patients with a-MCI and 17 healthy participants matched according to age and education participated in the study. The originality of the present study was to cue the recognition of facial expressions (happiness, anger, fear, and neutral) by comparing eye region expressions and entire facial expressions. Results: A deficit in the recognition of fearful expressions was observed in a-MCI patients relative to the control group, whereas recognition of all the other emotional expressions was spared. Nevertheless, when eye expressions cued the recognition of fearful facial expressions, the performance of normal controls and a-MCI patients was comparable. Conclusion: The present paper indicates a selective impairment in fear recognition in the prodromal state of Alzheimer’s disease, and the possibility of compensating this deficit by orienting selective attention on specific facial features.

International audience; The current study investigated if deficits in processing emotional expression affect facial identity processing and vice versa in children with autism spectrum disorder. Children with autism and IQ and age matched typically developing children classified faces either by emotional expression, thereby ignoring facial identity or by facial identity disregarding emotional expression. Typically developing children processed facial identity independently from facial expressions but processed facial expressions in interaction with identity. Children with autism processed both facial expression and identity independently of each other. They selectively directed their attention to one facial parameter despite variations in the other. Results indicate that there is no interaction in processing facial identity and emotional expression in autism spectrum disorder.

Recognition of a particular individual occurs when we reactivate links between current perceptual inputs and the previously formed representation of that person. This recognition can be achieved by identifying, separately or simultaneously, distinct elements such as the face, silhouette, or voice as belonging to one individual. In humans, those different cues are linked into one complex conceptual representation of individual identity. Here we tested whether rhesus macaques ( Macaca mulatta ) also have a cognitive representation of identity by evaluating whether they exhibit cross-modal individual recognition. Further, we assessed individual recognition of familiar conspecifics and familiar humans. In a free preferential looking time paradigm, we found that, for both species, monkeys spontaneously matched the faces of known individuals to their voices. This finding demonstrates that rhesus macaques possess a cross-modal cognitive representation of individuals that extends from conspecifics to humans, revealing the adaptive potential of identity recognition for individuals of socioecological relevance.

Recent application of theories of embodied or grounded cognition to the recognition and interpretation of facial expression of emotion has led to an explosion of research in psychology and the neurosciences. However, despite the accelerating number of reported findings, it remains unclear how the many component processes of emotion and their neural mechanisms actually support embodied simulation. Equally unclear is what triggers the use of embodied simulation versus perceptual or conceptual strategies in determining meaning. The present article integrates behavioral research from social psychology with recent research in neurosciences in order to provide coherence to the extant and future research on this topic. The roles of several of the brain's reward systems, and the amygdala, somatosensory cortices, and motor centers are examined. These are then linked to behavioral and brain research on facial mimicry and eye gaze. Articulation of the mediators and moderators of facial mimicry and gaze are particularly useful in guiding interpretation of relevant findings from neurosciences. Finally, a model of the processing of the smile, the most complex of the facial expressions, is presented as a means to illustrate how to advance the application of theories of embodied cognition in the study of facial expression of emotion.

International audience; Individuals with schizophrenia have difficulties in recognizing facial emotions in others. This study investigated whether this impairment also exists for self-generated expressions. Nineteen patients with schizophrenia and 19 comparison subjects were filmed while producing facial expressions in response to a visual model or a written sentence. After 2 months, all subjects were asked to rate their own emotional expressions. These ratings were compared with the evaluations of 12 healthy independent raters. With respect to the comparison subjects, the patients produced less expressive responses and were less able to recognize their own expressions. Moreover, patients were totally unaware of these impairments.

BackgroundTo investigate hedonic reactivity and the influence of unconscious emotional processes on the low sensitivity to positive reinforcement of food in anorexia nervosa (AN).MethodAN and healthy women were exposed to palatable food pictures just after a subliminal exposure to facial expressions (happy, disgust, fear and neutral faces), either while fasting or after a standardized meal (hungerversussatiety). Both implicit [facial electromyographic (EMG) activity from zygomatic and corrugator muscles, skin conductance, heart rate, and videotaped facial behavior] and explicit (self-reported pleasure and desire) measures of affective processes were recorded.ResultsIn contrast to healthy women, the AN patients did not display objective and subjective indices of pleasure to food pictures when they were in the hunger states. Pleasure to food cues (liking) was more affected than the desire to eat (wanting) in AN patients. Subliminal ‘fear faces’ increased corrugator muscle reactivity to food stimuli in fasting AN patients, as compared to controls.ConclusionsThe results suggest that unconscious fear cues increase the negative appraisal of alimentary stimuli in AN patients and thus contribute to decreased energy intake.

International audience; Gaze aversion could be a central component of the physiopathology of social phobia. The emotions of the people interacting with a person with social phobia seem to model this gaze aversion. Our research consists of testing gaze aversion in subjects with social phobia compared to control subjects in different emotional faces of men and women using an eye tracker. Twenty-six subjects with DSM-IV social phobia were recruited. Twenty-four healthy subjects aged and sex-matched constituted the control group. We looked at the number of fixations and the dwell time in the eyes area on the pictures. The main findings of this research are: confirming a significantly lower amount of fixations and dwell time in patients with social phobia as a general mean and for the 6 basic emotions independently from gender; observing a significant correlation between the severity of the phobia and the degree of gaze avoidance. However, no difference in gaze avoidance according to subject/picture gender matching was observed. These findings confirm and extend some previous results, and suggest that eye avoidance is a robust marker of persons with social phobia, which could be used as a behavioral phenotype for brain imagery studies on this disorder.

International audience; In The Expression of the Emotions, Charles Darwin documents evolutionary continuity between animals and humans, emphasizing the universality of expressions in man. Most of the book addresses human behavior, and its influence on the study of animal behavior has been weak. The issue of natural selection is remarkably absent from this book, which relies on the inheritance of acquired characters rather than on a genuine Darwinian logic. Yet Konrad Lorenz considered Darwin to be a forerunner of behavioral biology. The reason was to be found in The Descent of Man and chapter VIII of The Origin of Species, where Darwin provides an explanation of behavior through selection, stating that the same mechanisms explaining morphological changes also account for gradual improvements in instincts. He assessed the accuracy of his evolutionary theory by directly studying animal behavior, hence laying the foundations of behavioral research for the next century.

International audience; Human faces are the main emotion displayers. Knowing that emotional compared to neutral stimuli elicit enlarged ERPs components at the perceptual level, one may wonder whether this has led to an emotional facilitation bias toward human faces. To contribute to this question, we measured the P1 and N170 components of the ERPs elicited by human facial compared to artificial stimuli, namely non-humanoid robots. Fifteen healthy young adults were shown sad and neutral, upright and inverted expressions of human versus robotic displays. An increase in P1 amplitude in response to sad displays compared to neutral ones evidenced an early perceptual amplification for sadness information. P1 and N170 latencies were delayed in response to robotic stimuli compared to human ones, while N170 amplitude was not affected by media. Inverted human stimuli elicited a longer latency of P1 and a larger N170 amplitude while inverted robotic stimuli did not. As a whole, our results show that emotion facilitation is not biased to human faces but rather extend to non-human displays, thus suggesting our capacity to read emotion beyond faces.

International audience; Although normal subjects do not move during REM sleep, patients with Parkinson's disease may experience REM sleep behaviour disorder (RBD). The characteristics of the abnormal REM sleep movements in RBD have, however, not been studied. We interviewed one hundred consecutive non-demented patients with Parkinson's disease and their bed partners using a structured questionnaire assessing the presence of RBD. They rated the quality of movements, voice and facial expression during RBD as being better, equal or worse than in awake ON levodopa condition. Night-time sleep and movements were video-monitored during polysomnography in 51 patients to evaluate the presence of bradykinesia, tremor and hypophonia during REM sleep. Fifty-nine patients had clinical RBD with 53/59 bed partners able to evaluate them. All 53 (100%) reported an improvement of at least one component of motor control during RBD. By history, movements were improved in 87% patients (faster, 87%; stronger, 87%; smoother, 51%), speech was better in 77% patients (more intelligible, 77%; louder, 38%; better articulated, 57%) and facial expression was normalized in 47% patients. Thirty-eight per cent of bed partners reported that movements were 'much better', even in the most disabled patients. The video-monitored purposeful movements in REM sleep were also surprisingly fast, ample, coordinated and symmetrical, without obvious sign of parkinsonism. The movements were, however, jerky, violent and often repetitive. While all patients had asymmetrical parkinsonism when awake, most of the time they used the more disabled arm, hand and leg during the RBD (P = 0.04). Movements involved six times as often the upper limbs and the face as the lower limbs (OR: 5.9, P = 0.004). The percentage of time containing tremor EMG activity decreased with sleep stages from 34.9 +/- 15.5% during wakefulness, to 3.6 +/- 5.7% during non-REM sleep stages 1-2, 1.4 +/- 3.0% during non-REM sleep stages 3-4, and 0.06 +/- 0.2% during REM sleep (in this last case, it was subclinical tremor). The restored motor control during REM sleep suggests a transient 'levodopa-like' reestablishment of the basal ganglia loop. Alternatively, parkinsonism may disappear by REM sleep-related disjunction between pyramidal and extrapyramidal systems. We suggest the following model: the movements during the RBD would be generated by the motor cortex and would follow the pyramidal tract bypassing the extrapyramidal system. These movements would eventually be transmitted to lower motor neurons because of brainstem lesions interrupting the pontomedullary pathways which mediate the REM sleep atonia.

International audience; Although normal subjects do not move during REM sleep, patients with Parkinson's disease may experience REM sleep behaviour disorder (RBD). The characteristics of the abnormal REM sleep movements in RBD have, however, not been studied. We interviewed one hundred consecutive non-demented patients with Parkinson's disease and their bed partners using a structured questionnaire assessing the presence of RBD. They rated the quality of movements, voice and facial expression during RBD as being better, equal or worse than in awake ON levodopa condition. Night-time sleep and movements were video-monitored during polysomnography in 51 patients to evaluate the presence of bradykinesia, tremor and hypophonia during REM sleep. Fifty-nine patients had clinical RBD with 53/59 bed partners able to evaluate them. All 53 (100%) reported an improvement of at least one component of motor control during RBD. By history, movements were improved in 87% patients (faster, 87%; stronger, 87%; smoother, 51%), speech was better in 77% patients (more intelligible, 77%; louder, 38%; better articulated, 57%) and facial expression was normalized in 47% patients. Thirty-eight per cent of bed partners reported that movements were 'much better', even in the most disabled patients. The video-monitored purposeful movements in REM sleep were also surprisingly fast, ample, coordinated and symmetrical, without obvious sign of parkinsonism. The movements were, however, jerky, violent and often repetitive. While all patients had asymmetrical parkinsonism when awake, most of the time they used the more disabled arm, hand and leg during the RBD (P = 0.04). Movements involved six times as often the upper limbs and the face as the lower limbs (OR: 5.9, P = 0.004). The percentage of time containing tremor EMG activity decreased with sleep stages from 34.9 +/- 15.5% during wakefulness, to 3.6 +/- 5.7% during non-REM sleep stages 1-2, 1.4 +/- 3.0% during non-REM sleep stages 3-4, and 0.06 +/- 0.2% during REM sleep (in this last case, it was subclinical tremor). The restored motor control during REM sleep suggests a transient 'levodopa-like' reestablishment of the basal ganglia loop. Alternatively, parkinsonism may disappear by REM sleep-related disjunction between pyramidal and extrapyramidal systems. We suggest the following model: the movements during the RBD would be generated by the motor cortex and would follow the pyramidal tract bypassing the extrapyramidal system. These movements would eventually be transmitted to lower motor neurons because of brainstem lesions interrupting the pontomedullary pathways which mediate the REM sleep atonia.

Our facial expressions give others the opportunity to access our feelings, and constitute an important nonverbal tool for communication. Many recent studies have investigated emotional perception in adults, and our knowledge of neural processes involved in emotions is increasingly precise. Young children also use faces to express their internal states and perceive emotions in others, but little is known about the neurodevelopment of expression recognition. The goal of the current study was to determine the normal development of facial emotion perception. We recorded ERPs in 82 children 4 to 15 years of age during an implicit processing task with emotional faces. Task and stimuli were the same as those used and validated in an adult study; we focused on the components that showed sensitivity to emotions in adults (P1, N170 and frontal slow wave). An effect of the emotion expressed by faces was seen on the P1 in the youngest children. With increasing age this effect disappeared while an emotional sensitivity emerged on N170. Early emotional processing in young children differed from that observed in the adolescents, who approached adults. In contrast, the later frontal slow wave, although showing typical age effects, was more positive for neutral and happy faces across age groups. Thus, despite the precocious utilization of facial emotions, the neural processing involved in the perception of emotional faces develops in a staggered fashion throughout childhood, with the adult pattern appearing only late in adolescence.

The ability to properly distinguish facial emotions has a protracted development, not maturing until well into adolescence. Emotional faces activate emotion-specific neural networks in adults; whether these networks are operational in children is not known. Using an implicit face-processing task in 10-year-old children, we determined that the emotions of fear, disgust and sadness recruited distinct neural systems. These systems included a number of regions typically associated with processing emotions in adults, namely the amygdala and parahippocampal gyrus, insula and cingulate gyrus, as well as the fusiform and superior temporal gyri. Thus, in spite of immature behavioral responses to emotional faces in explicit tasks, neural networks for emotion-specific processing are present in young children.

International audience; We conducted a prospective controlled study of the clinical and biological determinants of the mental status abnormalities in 139 patients with Guillain-Barr?yndrome (GBS) and 55 patients without GBS placed in the intensive care unit (ICU controls). There were mental status changes in 31% of GBS patients and in 16% of controls (odds ratio = 2.3; P = 0.04). In GBS patients, they included vivid dreams (19%), illusions (30%, including an illusory body tilt), hallucinations (60%, mainly visual) and delusions (70%, mostly paranoid). They appeared a median 9 days after disease onset (range 1-40 days, during the progression or the plateau of the disease), and lasted a median 8 days. Seven (16%) patients experienced the symptoms before their admission to the ICU. Hallucinations were frequently hypnagogic, occurring as soon as the patients closed their eyes. Autonomic dysfunction, assisted ventilation and high CSF protein levels were significant risk factors for abnormal mental status in GBS patients. CSF hypocretin-1 (a hypothalamic neuropeptide deficient in narcolepsy) levels, measured in 20 patients, were lower in GBS patients with hallucinations (555 +/- 132 pg/ml) than in those without (664 +/- 71 pg/ml, P = 0.03). Since the mental status abnormalities had dream-like aspects, we examined their association with rapid eye movement sleep (REM sleep) using continuous sleep monitoring in 13 GBS patients with (n = 7) and without (n = 6) hallucinations and 6 tetraplegic ICU controls without hallucinations. Although sleep was short and fragmented in all groups, REM sleep latency was shorter in GBS patients with hallucinations (56 +/- 115 min) than in GBS patients without hallucinations (153 +/- 130 min) and in controls (207 +/- 179 min, P < 0.05). In addition, sleep structure was highly abnormal in hallucinators, with sleep onset in REM sleep periods (83%), abnormal eye movements during non-REM sleep (57%), high percentages of REM sleep without atonia (92 +/- 22%), REM sleep behaviour disorders and autonomic dysfunction (100%), reminiscent of a status dissociatus. The sleep abnormalities, that were almost absent in non-hallucinated GBS patients, were not exclusively related to ICU conditions, since they also appeared out of ICU, and were reversible, disappearing when the mental status abnormalities vanished while the patients were still in ICU. In conclusion, the mental status abnormalities experienced by GBS patients are different from the ICU delirium, are strongly associated with autonomic dysfunction, severe forms of the disease and possibly with a transitory hypocretin-1 transmission decrease. Sleep studies suggest that mental status abnormalities are wakeful dreams caused by a sleep and dream-associated disorder (status dissociatus).

International audience; BACKGROUND: It is well known that facial expressions represent important social cues. In humans expressing facial emotion, fear may be configured to maximize sensory exposure (e.g., increases visual input) whereas disgust can reduce sensory exposure (e.g., decreases visual input). To investigate whether such effects also extend to the attentional system, we used the "attentional blink" (AB) paradigm. Many studies have documented that the second target (T2) of a pair is typically missed when presented within a time window of about 200-500 ms from the first to-be-detected target (T1; i.e., the AB effect). It has recently been proposed that the AB effect depends on the efficiency of a gating system which facilitates the entrance of relevant input into working memory, while inhibiting irrelevant input. Following the inhibitory response on post T1 distractors, prolonged inhibition of the subsequent T2 is observed. In the present study, we hypothesized that processing facial expressions of emotion would influence this attentional gating. Fearful faces would increase but disgust faces would decrease inhibition of the second target. METHODOLOGY/PRINCIPAL FINDINGS: We showed that processing fearful versus disgust faces has different effects on these attentional processes. We found that processing fear faces impaired the detection of T2 to a greater extent than did the processing disgust faces. This finding implies emotion-specific modulation of attention. CONCLUSIONS/SIGNIFICANCE: Based on the recent literature on attention, our finding suggests that processing fear-related stimuli exerts greater inhibitory responses on distractors relative to processing disgust-related stimuli. This finding is of particular interest for researchers examining the influence of emotional processing on attention and memory in both clinical and normal populations. For example, future research could extend upon the current study to examine whether inhibitory processes invoked by fear-related stimuli may be the mechanism underlying the enhanced learning of fear-related stimuli.