Perception of facial expressions involves emotion specific somatosensory cortex activations which are shaped by alexithymia.

Somatosensory cortex (SCx) has been shown to crucially contribute to early perceptual processes when judging other's emotional facial expressions. Here, we investigated the specificity of SCx activity to angry, happy, sad and neutral emotions and the role of personality factors. We assessed participants' alexithymia (TAS-20) and depression (BDI) levels, their cardioceptive abilities and recorded changes in neural activity in a facial emotion judgment task. During the task, we presented tactile probes to reveal neural activity in SCx which was then isolated from visual carry-over responses. We further obtain SCx emotion effects by subtracting SCx activity elicited by neutral emotion expressions from angry, happy, and sad expressions. We find preliminary evidence for distinct modulations of SCx activity to angry and happy expressions. Moreover, the SCx anger response was predicted by individual differences in trait alexithymia. Thus, emotion expressions of others may be distinctly presented in the observer's neural body representation and may be shaped by their personality trait.

Somatosensory Evoked Potentials Reveal Reduced Embodiment of Emotions in Autism.

Consistent with current models of embodied emotions, this study investigates whether the somatosensory system shows reduced sensitivity to facial emotional expressions in autistic compared with neurotypical individuals, and whether these differences are independent from between-group differences in visual processing of facial stimuli. To investigate the dynamics of somatosensory activity over and above visual carryover effects, we recorded EEG activity from two groups of autism spectrum disorder (ASD) or typically developing (TD) humans (male and female), while they were performing a facial emotion discrimination task and a control gender task. To probe the state of the somatosensory system during face processing, in 50% of trials we evoked somatosensory activity by delivering task-irrelevant tactile taps on participants' index finger, 105 ms after visual stimulus onset. Importantly, we isolated somatosensory from concurrent visual activity by subtracting visual responses from activity evoked by somatosensory and visual stimuli. Results revealed significant task-dependent group differences in mid-latency components of somatosensory evoked potentials (SEPs). ASD participants showed a selective reduction of SEP amplitudes (P100) compared with TD during emotion task; and TD, but not ASD, showed increased somatosensory responses during emotion compared with gender discrimination. Interestingly, autistic traits, but not alexithymia, significantly predicted SEP amplitudes evoked during emotion, but not gender, task. Importantly, we did not observe the same pattern of group differences in visual responses. Our study provides direct evidence of reduced recruitment of the somatosensory system during emotion discrimination in ASD and suggests that this effect is not a byproduct of differences in visual processing.SIGNIFICANCE STATEMENT The somatosensory system is involved in embodiment of visually presented facial expressions of emotion. Despite autism being characterized by difficulties in emotion-related processing, no studies have addressed whether this extends to embodied representations of others' emotions. By dissociating somatosensory activity from visual evoked potentials, we provide the first evidence of reduced recruitment of the somatosensory system during emotion discrimination in autistic participants, independently from differences in visual processing between typically developing and autism spectrum disorder participants. Our study uses a novel methodology to reveal the neural dynamics underlying difficulties in emotion recognition in autism spectrum disorder and provides direct evidence that embodied simulation of others' emotional expressions operates differently in autistic individuals.

Embodiment and Multisensory Perception of Synchronicity: Biological Features Modulate Visual and Tactile Multisensory Interaction in Simultaneity Judgements.

The concept of embodiment has been used in multiple scenarios, but in cognitive neuroscience it normally refers to the comprehension of the role of one's own body in the cognition of everyday situations and the processes involved in that perception. Multisensory research is gradually embracing the concept of embodiment, but the focus has mostly been concentrated upon audiovisual integration. In two experiments, we evaluated how the likelihood of a perceived stimulus to be embodied modulates visuotactile interaction in a Simultaneity Judgement task. Experiment 1 compared the perception of two visual stimuli with and without biological attributes (hands and geometrical shapes) moving towards each other, while tactile stimuli were provided on the palm of the participants' hand. Participants judged whether the meeting point of two periodically-moving visual stimuli was synchronous with the tactile stimulation in their own hands. Results showed that in the hand condition, the Point of Subjective Simultaneity (PSS) was significantly more distant to real synchrony (60 ms after the Stimulus Onset Asynchrony, SOA) than in the geometrical shape condition (45 ms after SOA). In experiment 2, we further explored the impact of biological attributes by comparing performance on two visual biological stimuli (hands and ears), that also vary in their motor and visuotactile properties. Results showed that the PSS was equally distant to real synchrony in both the hands and ears conditions. Overall, findings suggest that embodied visual biological stimuli may modulate visual and tactile multisensory interaction in simultaneity judgements.

Beyond action observation: Neurobehavioral mechanisms of memory for visually perceived bodies and actions.

Examining the processing of others' body-related information in the perceivers' brain (action observation) is a key topic in cognitive neuroscience. However, what happens beyond the perceptual stage, when the body is not within view and it is transformed into an associative form that can be stored, updated, and later recalled, remains poorly understood. Here we examine neurobehavioural evidence on the memory processing of visually perceived bodily stimuli (dynamic actions and images of bodies). The reviewed studies indicate that encoding and maintaining bodily stimuli in memory recruits the sensorimotor system. This process arises when bodily stimuli are either recalled through action recognition or reproduction. Interestingly, the memory capacity for these stimuli is rather limited: only 2 or 3 bodily stimuli can be simultaneously held in memory. Moreover, this process is disrupted by increasing concurrent bodily operations; i.e., moving one's body, seeing or memorising additional bodies. Overall, the evidence suggests that the neural circuitry allowing us to move and feel ourselves supports the encoding, retention, and memory recall of others' visually perceived bodies.

The somatotopy of observed emotions.

The ability to experience others' emotional states is a key component in social interactions. Uniquely among sensorimotor regions, the somatosensory cortex (SCx) plays an especially important role in human emotion understanding. While distinct emotions are experienced in specific parts of the body, it remains unknown whether the SCx exhibits somatotopic activations to different emotional expressions. In the current study, we investigated if the affective response triggered by observing others' emotional face expressions leads to differential activations in SCx. Participants performed a visual facial emotion discrimination task while we measured changes in SCx topographic EEG activity by tactually stimulating two body-parts representative of the upper and lower limbs, the finger and the toe respectively. The results of the study showed an emotion specific response in the finger SCx when observing angry as opposed to sad emotional expressions, after controlling for carry-over effects of visual evoked activity. This dissociation to observed emotions was not present in toe somatosensory responses. Our results suggest that somatotopic activations of the SCx to discrete emotions might play a crucial role in understanding others' emotions.

Revealing the body in the brain: An ERP method to examine sensorimotor activity during visual perception of body-related information.

Examining the processing of others' body-related information in the perceivers' brain across the neurotypical and clinical population is a key topic in the domain of cognitive neurosciences. We argue that beyond classical neuroimaging techniques and frequency analyses, methods that can be easily adapted to capture the fast processing of body-related information in the brain are needed. Here we introduce a novel method that allows this by measuring event-related potentials recorded with electroencephalography (ERPs-EEG). This method possesses known EEG advantages (low cost, high temporal resolution, established paradigms) plus an improvement of its main limitation; i.e., spatiotemporally smoothed resolution due to mixed neural sources. This occurs when participants are presented and process images of bodies/actions that recruit posterior visual cortices. Such stimulus-evoked activity may spread and mask the recording of simultaneous activity arising from sensorimotor brain areas, which also process body-related information. Therefore, it is difficult to dissociate the contributing role of different brain regions. To overcome this, we propose eliciting a combination of somatosensory, motor, and visual-evoked potentials during processing of body-related information (vs non-body-related). Next, brain activity from sensorimotor and visual systems can be dissociated by subtracting activity from trials containing only visual-evoked potentials to those trials containing either a mixture of visual and somatosensory or visual and motor-cortical potentials. This allows isolating visually driven neural activity in areas other than visual. To introduce this method, we revise recent work using this method, consider the processing of body-related stimuli in the brain, as well as outline key methodological aspects to-be-considered. This work provides a clear guideline to researchers interested or transitioning from behavioural to ERPs studies, offering the possibility to adapt well-established paradigms in the EEG realm to study others' body-related processing in the perceiver's own cortical body representation (e.g., examining classical EEG components in the social and embodiment frameworks).

Interoceptive impairments do not lie at the heart of autism or alexithymia.

Quattrocki and Friston (2014) argued that abnormalities in interoception-the process of representing one's internal physiological states-could lie at the heart of autism, because of the critical role interoception plays in the ontogeny of social-affective processes. This proposal drew criticism from proponents of the alexithymia hypothesis, who argue that social-affective and underlying interoceptive impairments are not a feature of autism per se, but of alexithymia (a condition characterized by difficulties describing and identifying one's own emotions), which commonly co-occurs with autism. Despite the importance of this debate for our understanding of autism spectrum disorder (ASD), and of the role of interoceptive impairments in psychopathology, more generally, direct empirical evidence is scarce and inconsistent. Experiment 1 examined in a sample of 137 neurotypical (NT) individuals the association among autistic traits, alexithymia, and interoceptive accuracy (IA) on a standard heartbeat-tracking measure of IA. In Experiment 2, IA was assessed in 46 adults with ASD (27 of whom had clinically significant alexithymia) and 48 NT adults. Experiment 1 confirmed strong associations between autistic traits and alexithymia, but yielded no evidence to suggest that either was associated with interoceptive difficulties. Similarly, Experiment 2 provided no evidence for interoceptive impairments in autistic adults, irrespective of any co-occurring alexithymia. Bayesian analyses consistently supported the null hypothesis. The observations pose a significant challenge to notions that interoceptive impairments constitute a core feature of either ASD or alexithymia, at least as far as the direct perception of interoceptive signals is concerned. (PsycINFO Database Record

Modulation of motor cortex activity in a visual working memory task of hand images.

Recent studies suggest that brain regions engaged in perception are also recruited during the consolidation interval of the percept in working memory (WM). Evidence for this comes from studies showing that maintaining arbitrary visual, auditory, and tactile stimuli in WM elicits recruitment of the corresponding sensory cortices. Here we investigate if encoding and WM maintenance of visually perceived body-related stimuli engage just visual regions, or additional sensorimotor regions that are classically associated with embodiment processes in studies of body and action perception. We developed a novel WM paradigm in which participants were asked to remember body and control non-body-related images. In half of the trials, visual-evoked activity that was time-locked to the sight of the stimuli allowed us to examine visual processing of the stimuli to-be-remembered (visual-only trials). In the other half of the trials we additionally elicited a task irrelevant key pressing during the consolidation interval of the stimuli in WM. This manipulation elicited motor-cortical potentials (MCPs) concomitant to visual processing (visual-motor trials). This design allowed us to dissociate motor activity depicted in the MCPs from concurrent visual processing by subtracting activity from the visual-only trials to the compound activity found in the visual-motor trials. After dissociating the MCPs from concomitant visual activity, the results show that only the body-related images elicited neural recruitment of sensorimotor regions over and above visual effects. Importantly, the number of body stimuli to-be-remembered (memory load) modulated this later motor cortical activity. The current observations link together research in embodiment and WM by suggesting that neural recruitment is driven by the nature of the information embedded in the percept.

I can feel my heartbeat: Dancers have increased interoceptive accuracy.

Interoception is the process of perceiving afferent signals arising from within the body including heart rate (HR), gastric signals, etc., and has been described as a mechanism crucially involved in the creation of self-awareness and selfhood. The heartbeat perception task is a tool to measure individuals' interoceptive accuracy (IAcc). IAcc correlates positively with measures of self-awareness and with attributes including emotional sensitivity, empathy, prosocial behavior, and efficient decision making. IAcc is only moderate in the general population, and attempts to identify groups of people who might have higher IAcc due to their specific training (e.g., yoga, meditation) have not been successful. However, a recent study with musicians suggests that those trained in the arts might exhibit high IAcc. Here, we tested IAcc in 20 professional dancers and 20 female control participants on a heartbeat perception task. Dancers had a higher IAcc, and this effect was independent of their lower heart rates (a proxy measure of physical fitness), counting ability, and knowledge about HR. An additional between-groups analysis after a median split in the dancer group (based on years of dance experience) showed that junior dancers' IAcc differed from controls, and senior dancers' IAcc was higher than both junior dancers and controls. General art experience correlated positively with IAcc. No correlations were found between IAcc and questionnaire measures of empathy, emotional experience, and alexithymia. These findings are discussed in the context of current theories of interoception and emotion-highlighting the features of arts training that might be related to IAcc.

Dance expertise modulates behavioral and psychophysiological responses to affective body movement.

The present study shows how motor expertise increases individuals' sensitivity to others' affective body movement. This enhanced sensitivity is evident in the experts' behavior and physiology. Nineteen affective movement experts (professional ballet dancers) and 24 controls watched 96 video clips of emotionally expressive body movements while they performed an affect rating task (subjective response), and their galvanic skin response was recorded (physiological response). The movements in the clips were either sad or happy, and in half of the trials, movements were played in the order in which they are learned (forward presentation), and in the other half, movements were played backward (control condition). Results showed that motor expertise in affective body movement specifically modulated both behavioral and physiological sensitivity to others' affective body movement, and that this sensitivity is particularly strong when movements are shown in the way they are learnt (forward presentation). The evidence is discussed within current theories of proprioceptive arousal feedback and motor simulation accounts. (PsycINFO Database Record

When you smile, the world smiles at you: ERP evidence for self-expression effects on face processing.

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, neutral faces are processed similarly to happy faces. When making a neutral expression or pursing the lips, however, responses to neutral and happy face are significantly different. This effect was source localized within multisensory associative areas, angular gyrus, associative visual cortex and somatosensory cortex. We provide novel evidence that one's own emotional expression acts as a top-down influence modulating low-level neural encoding during facial perception.

Episodic Recollection Difficulties in ASD Result from Atypical Relational Encoding: Behavioral and Neural Evidence.

Memory functioning in Autism Spectrum Disorder (ASD) is characterized by impairments in the encoding of relational but not item information and difficulties in the recollection of contextually rich episodic memories but not in the retrieval of relatively context-free memories through processes of familiarity. The neural underpinnings of this profile and the extent to which encoding difficulties contribute to retrieval difficulties in ASD remain unclear. Using a paradigm developed by Addis and McAndrews [2006; Neuroimage, 33, 1194-1206] we asked adults with and without a diagnosis of ASD to study word-triplets during functional Magnetic Resonance Imaging (fMRI) scanning that varied in the number of category relations amongst component words. Performance at test confirmed attenuated recollection in the context of preserved familiarity based retrieval in ASD. The results also showed that recollection but not familiarity based retrieval increases as a function of category relations in word triads for both groups, indicating a close link between the encoding of relational information and recollection. This link was further supported by the imaging results, where blood oxygen level dependent (BOLD) signal responses in overlapping regions of the inferior prefrontal cortex were sensitive to the relational encoding manipulation as well as the contrast between recollection versus familiarity based retrieval. Interestingly, however, there was no evidence of prefrontal signal differentiation for this latter contrast in the ASD group for whom signal changes in a left hippocampal region were also marginally attenuated. Together, these observations suggest that attenuated levels of episodic recollection in ASD are, at least in part, attributable to anomalies in relational encoding processes.

"Some like it hot": spectators who score high on the personality trait openness enjoy the excitement of hearing dancers breathing without music.

Music is an integral part of dance. Over the last 10 years, however, dance stimuli (without music) have been repeatedly used to study action observation processes, increasing our understanding of the influence of observer's physical abilities on action perception. Moreover, beyond trained skills and empathy traits, very little has been investigated on how other observer or spectators' properties modulate action observation and action preference. Since strong correlations have been shown between music and personality traits, here we aim to investigate how personality traits shape the appreciation of dance when this is presented with three different music/sounds. Therefore, we investigated the relationship between personality traits and the subjective esthetic experience of 52 spectators watching a 24 min lasting contemporary dance performance projected on a big screen containing three movement phrases performed to three different sound scores: classical music (i.e., Bach), an electronic sound-score, and a section without music but where the breathing of the performers was audible. We found that first, spectators rated the experience of watching dance without music significantly different from with music. Second, we found that the higher spectators scored on the Big Five personality factor openness, the more they liked the no-music section. Third, spectators' physical experience with dance was not linked to their appreciation but was significantly related to high average extravert scores. For the first time, we showed that spectators' reported entrainment to watching dance movements without music is strongly related to their personality and thus may need to be considered when using dance as a means to investigate action observation processes and esthetic preferences.

Enhancing emotional experiences to dance through music: the role of valence and arousal in the cross-modal bias.

It is well established that emotional responses to stimuli presented to one perceptive modality (e.g., visual) are modulated by the concurrent presentation of affective information to another modality (e.g., auditory)-an effect known as the cross-modal bias. However, the affective mechanisms mediating this effect are still not fully understood. It remains unclear what role different dimensions of stimulus valence and arousal play in mediating the effect, and to what extent cross-modal influences impact not only our perception and conscious affective experiences, but also our psychophysiological emotional response. We addressed these issues by measuring participants' subjective emotion ratings and their Galvanic Skin Responses (GSR) in a cross-modal affect perception paradigm employing videos of ballet dance movements and instrumental classical music as the stimuli. We chose these stimuli to explore the cross-modal bias in a context of stimuli (ballet dance movements) that most participants would have relatively little prior experience with. Results showed (i) that the cross-modal bias was more pronounced for sad than for happy movements, whereas it was equivalent when contrasting high vs. low arousal movements; and (ii) that movement valence did not modulate participants' GSR, while movement arousal did, such that GSR was potentiated in the case of low arousal movements with sad music and when high arousal movements were paired with happy music. Results are discussed in the context of the affective dimension of neuroentrainment and with regards to implications for the art community.

The emotional homunculus: ERP evidence for independent somatosensory responses during facial emotional processing.

Current models of face perception propose that initial visual processing is followed by activation of nonvisual somatosensory areas that contributes to emotion recognition. To test whether there is a pure and independent involvement of somatosensory cortex (SCx) during face processing over and above visual responses, we directly measured participants' somatosensory-evoked activity by tactually probing (105 ms postvisual facial stimuli) the state of SCx during an emotion discrimination task while controlling for visual effects. Discrimination of emotional versus neutral expressions enhanced early somatosensory-evoked activity between 40 and 80 ms after stimulus onset, suggesting visual emotion processing in SCx. This effect was source localized within primary, secondary, and associative somatosensory cortex. Emotional face processing influenced somatosensory responses to both face (congruent body part) and finger (control site) tactile stimulation, suggesting a general process that includes nonfacial cortical representations. Gender discrimination of the same facial expressions did not modulate somatosensory-evoked activity. We provide novel evidence that SCx activation is not a byproduct of visual processing but is independently shaped by face emotion processing.

Recognition of dance-like actions: memory for static posture or dynamic movement?

Dance-like actions are complex visual stimuli involving multiple changes in body posture across time and space. Visual perception research has demonstrated a difference between the processing of dynamic body movement and the processing of static body posture. Yet, it is unclear whether this processing dissociation continues during the retention of body movement and body form in visual working memory (VWM). When observing a dance-like action, it is likely that static snapshot images of body posture will be retained alongside dynamic images of the complete motion. Therefore, we hypothesized that, as in perception, posture and movement would differ in VWM. Additionally, if body posture and body movement are separable in VWM, as form- and motion-based items, respectively, then differential interference from intervening form and motion tasks should occur during recognition. In two experiments, we examined these hypotheses. In Experiment 1, the recognition of postures and movements was tested in conditions in which the formats of the study and test stimuli matched (movement-study to movement-test, posture-study to posture-test) or mismatched (movement-study to posture-test, posture-study to movement-test). In Experiment 2, the recognition of postures and movements was compared after intervening form and motion tasks. These results indicated that (1) the recognition of body movement based only on posture is possible, but it is significantly poorer than recognition based on the entire movement stimulus, and (2) form-based interference does not impair memory for movements, although motion-based interference does. We concluded that, whereas static posture information is encoded during the observation of dance-like actions, body movement and body posture differ in VWM.

[Neuroarchitecture of musical emotions]. / Neuroarquitectura de la emocion musical.

The emotional response to music, or musical emotion, is a universal response that draws on diverse psychological processes implemented in a large array of neural structures and mechanisms. Studies using electroencephalography, functional magnetic resonance, lesions and individuals with extent musical training have begun to elucidate some of these mechanisms. The objective of this article is reviewing the most relevant studies that have tried to identify the neural correlates of musical emotion from the more automatic to the more complex processes, and to understand how these correlates interact in the brain. The article describes how the presentation of music perceived as emotional is associated with a rapid autonomic response in thalamic and subthalamic structures, accompanied by changes in the electrodermal and endocrine responses. It also explains how musical emotion processing activates auditory cortex, as well as a series of limbic and paralimbic structures, such as the amygdala, the anterior cingulate cortex or the hippocampus, demonstrating the relevant contribution of the limbic system to musical emotion. Further, it is detailed how musical emotion depends to a great extent on semantic and syntactic process carried out in temporal and parietofrontal areas, respectively. Some of the recent works demonstrating that musical emotion highly relies on emotional simulation are also mentioned. Finally, a summary of these studies, their limitations, and suggestions for further research on the neuroarchitecture of musical emotion are given.

Neurocognitive control in dance perception and performance.

Dance is a rich source of material for researchers interested in the integration of movement and cognition. The multiple aspects of embodied cognition involved in performing and perceiving dance have inspired scientists to use dance as a means for studying motor control, expertise, and action-perception links. The aim of this review is to present basic research on cognitive and neural processes implicated in the execution, expression, and observation of dance, and to bring into relief contemporary issues and open research questions. The review addresses six topics: 1) dancers' exemplary motor control, in terms of postural control, equilibrium maintenance, and stabilization; 2) how dancers' timing and on-line synchronization are influenced by attention demands and motor experience; 3) the critical roles played by sequence learning and memory; 4) how dancers make strategic use of visual and motor imagery; 5) the insights into the neural coupling between action and perception yielded through exploration of the brain architecture mediating dance observation; and 6) a neuroesthetics perspective that sheds new light on the way audiences perceive and evaluate dance expression. Current and emerging issues are presented regarding future directions that will facilitate the ongoing dialog between science and dance.

Experts see it all: configural effects in action observation.

Biological motion perception is influenced by observers' familiarity with the observed action. Here, we used classical dance as a means to investigate how visual and motor experience modulates perceptual mechanism for configural processing of actions. Although some ballet moves are performed by only one gender, male and female dancers train together and acquire visual knowledge of all ballet moves. Twenty-four expert ballet dancers (12 female) and matched non-expert participants viewed pairs of upright and inverted point light female and common dance movements. Visual discrimination between different exemplars of the same movement presented upright was significantly better in experts than controls, whilst no differences were found when the same stimuli were presented upside down. These results suggest expertise influences configural action processing. Within the expert group, effects were stronger for female participants than for males, whilst no differences were found between movement types. This observer gender effect could suggest an additional role for motor familiarity in action perception, over and above the visual experience. Our results are consistent with a specific motor contribution to configural processing of action.