Defective comprehension of emotional faces and prosody as a result of right hemisphere stroke: modality versus emotion-type specificity.

Studies of patients with brain damage, as well as studies with normal subjects have revealed that the right hemisphere is important for recognizing emotions expressed by faces and prosody. It is unclear, however, if the knowledge needed to perform recognition of emotional stimuli is organized by modality or by the type of emotion. Thus, the purpose of this study is to assess these alternative a priori hypotheses. The participants of this study were 30 stroke patients with right hemisphere damage (RHD) and 31 normal controls (NC). Subjects were assessed with the Polish adaptation of the Right Hemisphere Language Battery of Bryan and the Facial Affect Recognition Test based on work of Ekman and Friesen. RHD participants were significantly impaired on both emotional tasks. Whereas on the visual-faces task the RHD subjects recognized happiness better than anger or sadness, the reverse dissociation was found in the auditory-prosody test. These results confirm prior studies demonstrating the role of the right hemisphere in understanding facial and prosodic emotional expressions. These results also suggest that the representations needed to recognize these emotional stimuli are organized by modality (prosodic-echoic and facial-eidetic) and that some modality specific features are more impaired than others.     

Perception of emotions from faces and voices following unilateral brain damage

The importance of the right hemisphere in emotion perception in general has been well documented but its precise role is disputed. We compared the performance of 30 right hemisphere damaged (RHD) patients, 30 left hemisphere damaged (LHD) patients, and 50 healthy controls on both facial and vocal affect perception tasks of specific emotions. Brain damaged subjects had a single episode cerebrovascular accident localised to one hemisphere. The results showed that right hemisphere patients were markedly impaired relative to left hemisphere and healthy controls on test performance: labelling and recognition of facial expressions and recognition of emotions conveyed by prosody. This pertained at the level of individual basic emotions, positive versus negative, and emotional expressions in general. The impairment remained highly significant despite covarying for the group's poorer accuracy on a neutral facial perception test and identification of neutral vocal expressions. The LHD group were only impaired relative to controls on facial emotion tasks when their performance was summed over all the emotion categories and before age and other cognitive factors were taken into account. However, on the prosody test the LHD patients showed significant impairment, performing mid-way between the right hemisphere patients and healthy comparison group. Recognition of positive emotional expressions was better than negative in all subjects, and was not relatively poorer in the LHD patients. Recognition of individual emotions in one modality correlated weakly with recognition in another, in all three groups. These data confirm the primacy of the right hemisphere in processing all emotional expressions across modalities--both positive and negative--but suggest that left hemisphere emotion processing is modality specific. It is possible that the left hemisphere has a particular role in the perception of emotion conveyed through meaningful speech.     

Face processing, laterality and contrast sensitivity

Two separate reaction time studies concerning person recognition were conducted with ex-servicemen who incurred unilateral brain injury during the Second World War. The first experiment investigated the ability to construct a facial representation and involved deciding whether a stimulus represented a face or a "non-face" made by repositioning the facial features into an unnatural configuration. Men with posterior right hemisphere (RH) lesions performed this task more slowly than those with left hemisphere (LH) damage and control subjects; the latter two groups did not differ. The second experiment was designed to tap the most basic level of overt person recognition: awareness of familiarity. When faces were used as stimuli, the RH injured group again showed increased response latencies compared with the other two groups. The reverse pattern, slower reaction times for the men with LH lesions with no difference between RH injured and control subjects, emerged when written names were employed. Spatial contrast sensitivity functions were measured in both studies and although both LH and RH injured men showed impaired contrast sensitivity, no hemispheric difference was apparent. Instead, a double dissociation of impairments of contrast sensitivity and face processing was evident.     

Specific impairments in the recognition of emotional facial expressions in Parkinson's disease

Studies investigating the ability to recognize emotional facial expressions in non-demented individuals with Parkinson's disease (PD) have yielded equivocal findings. A possible reason for this variability may lie in the confounding of emotion recognition with cognitive task requirements, a confound arising from the lack of a control condition using non-emotional stimuli. The present study examined emotional facial expression recognition abilities in 20 non-demented patients with PD and 23 control participants relative to their performance on a non-emotional landscape categorization test with comparable task requirements. We found that PD participants were normal on the control task but exhibited selective impairments in the recognition of facial emotion, specifically for anger (driven by those with right hemisphere pathology) and surprise (driven by those with left hemisphere pathology), even when controlling for depression level. Male but not female PD participants further displayed specific deficits in the recognition of fearful expressions. We suggest that the neural substrates that may subserve these impairments include the ventral striatum, amygdala, and prefrontal cortices. Finally, we observed that in PD participants, deficiencies in facial emotion recognition correlated with higher levels of interpersonal distress, which calls attention to the significant psychosocial impact that facial emotion recognition impairments may have on individuals with PD.     

A leftward bias however you look at it: Revisiting the emotional chimeric face task as a tool for measuring emotion lateralization

ABSTRACT

Left hemiface biases observed within the Emotional Chimeric Face Task (ECFT) support emotional face perception models whereby all expressions are preferentially processed by the right hemisphere. However, previous research using this task has not considered that the visible midline between hemifaces might engage atypical facial emotion processing strategies in upright or inverted conditions, nor controlled for left visual field (thus right hemispheric) visuospatial attention biases. This study used novel emotional chimeric faces (blended at the midline) to examine laterality biases for all basic emotions. Left hemiface biases were demonstrated across all emotional expressions and were reduced, but not reversed, for inverted faces. The ECFT bias in upright faces was significantly increased in participants with a large attention bias. These results support the theory that left hemiface biases reflect a genuine bias in emotional face processing, and this bias can interact with attention processes similarly localized in the right hemisphere.     

Orbitofrontal cortex lesions result in abnormal social judgements to emotional faces

Facial expressions of emotion display a wealth of important social information that we use to guide our social judgements. The aim of the current study was to investigate whether patients with orbitofrontal cortex (OFC) lesions exhibit an impaired ability to judge the approachability of emotional faces. Furthermore, we also intended to establish whether impaired approachability judgements provided to emotional faces emerged in the presence of preserved explicit facial expression recognition. Using non-parametric statistics, we found that patients with OFC lesions had a particular difficulty using negative facial expressions to guide approachability judgements, compared to healthy controls and patients with frontal lesions sparing the OFC. Importantly, this deficit arose in the absence of an explicit facial expression recognition deficit. In our sample of healthy controls, we also demonstrated that the capacity to recognise facial expressions was not significantly correlated with approachability judgements given to emotional faces. These results demonstrate that the integrity of the OFC is critical for the appropriate assessment of approachability from negatively valenced faces and this ability is functionally dissociable from the capacity to explicitly recognise facial expressions.     

Cognitively preserved MS patients demonstrate functional differences in processing neutral and emotional faces

The ability to recognize emotional facial expressions is crucial to adequate social behavior. Previous studies have suggested deficits in emotion recognition in multiple sclerosis (MS). These deficits were accompanied by several confounders including cognitive or visual impairments, disease duration, and depression. In our study we used functional MRI (fMRI) to test for potential early adaptive changes in only mildly disabled MS patients performing an emotion recognition task including the facial expressions of the emotions anger, fear and disgust. Fifteen relapsing-remitting MS patients with a median Expanded Disability Status Scale (EDSS) score of 2 (range: 0-3.5) and 15 healthy controls (HC) matched for age, gender, and education underwent behavioral (BERT: behavioral emotion recognition test; BRB-N: Brief Repeatable Battery for neuropsychological tests, WCST: Wisconsin Card Sorting Test) and clinical assessments (BDI: Beck Depression Inventory). Conventional MRI at 3.0T served to assess whole-brain volume, white matter, gray matter, cerebrospinal fluid, and T2-lesion load; during fMRI, participants were confronted with neutral, scrambled, angry, disgusted, and fearful faces, and houses. In the absence of differences in cognitive performance and in the ability to accurately recognize distinct emotional facial expressions, MS patients demonstrated excess fMRI activations during facial recognition compared to HC. These differences concerned the posterior cingulate cortex (PCC) and precuneus for anger and disgust contrasted to neutral faces, and the occipital fusiform gyri and the anterior CC for neutral faces versus houses. This study provides first evidence for excess activation during processing of higher order visual stimuli of emotional content in the absence of emotional, visual or cognitive behavior abnormalities already in earlier stages of MS.     

Emotional memory and perception in temporal lobectomy patients with amygdala damage

BACKGROUND: The human amygdala is implicated in the formation of emotional memories and the perception of emotional stimuli--particularly fear--across various modalities. OBJECTIVES: To discern the extent to which these functions are related. METHODS: 28 patients who had anterior temporal lobectomy (13 left and 15 right) for intractable epilepsy were recruited. Structural magnetic resonance imaging showed that three of them had atrophy of their remaining amygdala. All participants were given tests of affect perception from facial and vocal expressions and of emotional memory, using a standard narrative test and a novel test of word recognition. The results were standardised against matched healthy controls. RESULTS: Performance on all emotion tasks in patients with unilateral lobectomy ranged from unimpaired to moderately impaired. Perception of emotions in faces and voices was (with exceptions) significantly positively correlated, indicating multimodal emotional processing. However, there was no correlation between the subjects' performance on tests of emotional memory and perception. Several subjects showed strong emotional memory enhancement but poor fear perception. Patients with bilateral amygdala damage had greater impairment, particularly on the narrative test of emotional memory, one showing superior fear recognition but absent memory enhancement. CONCLUSIONS: Bilateral amygdala damage is particularly disruptive of emotional memory processes in comparison with unilateral temporal lobectomy. On a cognitive level, the pattern of results implies that perception of emotional expressions and emotional memory are supported by separate processing systems or streams.     

Lateralisation effect in comprehension of emotional facial expression: A comparison between EEG alpha band power and behavioural inhibition (BIS) and activation (BAS) systems

Asymmetry in comprehension of facial expression of emotions was explored in the present study by analysing alpha band variation within the right and left cortical sides. Second, the behavioural activation system (BAS) and behavioural inhibition system (BIS) were considered as an explicative factor to verify the effect of a motivational/emotional variable on alpha activity. A total of 19 participants looked at an ample range of facial expressions of emotions (anger, fear, surprise, disgust, happiness, sadness, and neutral) in random order. The results demonstrated that anterior frontal sites were more active than central and parietal sites in response to facial stimuli. Moreover, right and left side responses varied as a function of emotional types, with an increased right frontal activity for negative, aversive emotions vs an increased left response for positive emotion. Finally, whereas higher BIS participants generated more right hemisphere activation for some negative emotions (such as fear, anger, surprise, and disgust), BAS participants were more responsive to positive emotion (happiness) within the left hemisphere. Motivational significance of facial expressions was considered to elucidate cortical differences in participants' responses to emotional types.     

Hemispheric specialization in nonverbal communication

Subjects sustaining right hemisphere damage were impaired in the ability to evaluate emotional situations presented through nonverbal means, particularly through facial expressions. Left brain damage, even of considerable extent, led to significantly milder deficits. In agreement with these findings, a study in split-brain patients showed the isolated right hemisphere to be competent in evaluating facial expressions but less sensitive to body movements, while the left hemisphere showed the opposite pattern.     

Impairments in judgment of chimeric faces by schizophrenic and affective patients.

The hypothesis that schizophrenic and affective patients have differential impairments in judgment of facial emotional expressions was tested on 55 right-handed patients: 15 in each of two groups of schizophrenic patients, with positive and negative symptoms; and 10 in each of two groups of bipolar affective patients, in manic and depressive states. In addition, 37 normal control subjects were also tested. The subjects were presented with eight schematic drawings of chimeric faces (each depicting a positive emotion in a given hemiface, and a negative emotion in the other hemiface), as well as with two drawings of composite faces (each depicting either a positive or a negative emotion). Subjects judged the emotions depicted by the facial expressions, as well as their intensity. The data, analyzed by analyses of variance, showed that normals judged the chimeric expressions on the basis of the emotions depicted by the left hemifaces. This tendency was weaker among the psychiatric patients. Schizophrenics with negative symptoms judged positive expressions in the left hemifaces as depicting negative emotions, and negative expressions as depicting positive emotions. Schizophrenics with positive symptoms and manic patients judged all expressions as depicting positive emotions. Depressive patients showed a stronger tendency to judge negative expressions as depicting negative emotions than positive expressions as depicting positive emotions. No significant group differences appeared in judgment of composite faces (except for schizophrenic with negative symptoms who were more accurate in judging positive than negative expressions). Patients performances were interpreted in terms of differential dysfunctions in posterior areas of the right cerebral hemisphere which might be associated with bilateral effects of dysfunctions in anterior cerebral areas.     

Facial emotion recognition in trait anxiety

The study investigated the relationship between recognition of emotional facial expressions and trait anxiety. A nonclinical sample of 19 participants with high-trait anxiety was selected, using the trait version of the State-Trait Anxiety Inventory, and compared with a sample of 20 participants with low-trait anxiety on a facial expression recognition task. Visual stimuli were 42 faces, representing seven emotional expressions: anger, sadness, happiness, fear, surprise, disgust and neutral. Participants had to identify the emotion portrayed by each face. Results showed that participants with high-trait anxiety recognized fear faces significantly better while the two groups did not differ in recognition of other facial expressions.     

Abnormal emotional word ratings in Parkinson's disease

Blunted facial expressions and diminished expressions of emotional prosody associated with Parkinson's disease (PD) could be attributed to motor rigidity/akinesia. Although impaired recognition of emotional faces and prosody in PD suggests emotional dysfunction is not entirely motor-efferent, comprehension might depend upon imitation with motor feedback. Thus, to learn if patients with PD have an emotional conceptual defect, we examined their ratings for the emotional connotations of words on a 1-9 scale for valence and arousal. When compared to control participants the valence (positive-negative) and arousal (excited-calm) ratings of the PD patients were blunted, but their ratings of the control expense words (expensive-cheap) were not. These blunted emotion ratings suggest that patients with PD have a degradation of their emotional conceptual-semantic system.     

Appreciation of emotional expressions in the visual and auditory modality in normal and brain-damaged patients

Right-handed patients with right-sided, left-sided or without brain lesions, were tested for their appreciation of pictures of faces and tape-recorded voices carrying emotional expressions. The right hemisphere group was impaired in relation to the left and normal group. On the auditory test the impaired right-sided group showed confusion of all emotional categories. On the visual test, the same patients evaluated all emotional qualities to be happy or neutral. It is suggested that different mechanisms explain these findings: one of defective perceptual analysis, prominent in the auditory test, and one of change of mood in an euphoric direction specific to patients suffering damage to the right hemisphere.     

Reactions of patients with focal cerebral lesions to success or failure

Multiple measures were used to investigate emotional reactions to card sorting in patients with focal cerebral lesions and in matched non-brain-injured controls. Spontaneous facial expressions of patients with anterior lesions were impoverished, relative to the posterior group, on a quantitative index of facial movement. This deficit did not appear to be attributable to group differences on lesion variables, or degree of cognitive deficit. There were also indications that a "non-emotional" facial-motor deficit was not the primary cause. The marked anterior deficit for facial movement was not, however, associated with equally pronounced deficits on qualitative, self-report and heart rate indices of emotional response. Right hemisphere patients differed from left hemisphere patients on only one qualitative measure of emotional reaction, but this may have been due to the stronger negative reactions of dysphasic patients. Left unilateral neglect was not associated with reduced emotional response.     

A reversal of the normal pattern of parahippocampal response to neutral and fearful faces is associated with reality distortion in schizophrenia.

BACKGROUND: Individuals with schizophrenia demonstrate impaired recognition of facial expressions and may misattribute emotional salience to otherwise nonsalient stimuli. The neural mechanisms underlying this deficit and the relationship with different symptoms remain poorly understood. METHODS: We used event-related functional magnetic resonance imaging to measure neural responses to neutral, mildly fearful, and prototypically fearful facial expressions. The sample included 15 medicated individuals with chronic schizophrenia (SZ) and 11 healthy control individuals (CON), matched for gender (all male), age, and years of education. RESULTS: A repeated measures 3 x 2 analysis of variance (ANOVA) revealed a significant interaction between expression intensity and group in right parahippocampal gyrus (p < .01). Individuals with chronic schizophrenia demonstrated a decrease, whereas CON showed an increase, in right parahippocampal gyrus response to increasingly fearful expressions. Between-group comparison revealed greater activation in SZ than CON in right parahippocampal gyrus to neutral faces. The reality distortion dimension, but not neuroleptic medication dose, was positively associated with the right parahippocampal gyral and right amygdalar response to neutral faces in SZ. CONCLUSIONS: An abnormally increased parahippocampal response to neutral faces was positively associated with reality distortion in SZ. This may underlie the previously reported finding of a misattribution of emotional salience to nonsalient social stimuli in schizophrenia.     

Social and emotional processing in Prader-Willi syndrome: genetic subtype differences

Background

People with Prader-Willi syndrome (PWS) demonstrate social dysfunction and increased risk of autism spectrum disorder, especially those with the maternal uniparental disomy (mUPD) versus paternal deletion genetic subtype. This study compared the neural processing of social (faces) and nonsocial stimuli, varying in emotional valence, across genetic subtypes in 24 adolescents and adults with PWS.

Methods

Upright and inverted faces, and nonsocial objects with positive and negative emotional valence were presented to participants with PWS in an oddball paradigm with smiling faces serving as targets. Behavioral and event-related potential (ERP) data were recorded.

Results

There were no genetic subtype group differences in accuracy, and all participants performed above chance level. ERP responses revealed genetic subtype differences in face versus object processing. In those with deletions, the face-specific posterior N170 response varied in size for face stimuli versus inverted faces versus nonsocial objects. Persons with mUPD generated N170 of smaller amplitude and showed no stimulus differentiation. Brain responses to emotional content did not vary by subtype. All participants elicited larger posterior and anterior late positive potential responses to positive objects than to negative objects. Emotion-related differences in response to faces were limited to inverted faces only in the form of larger anterior late positive potential amplitudes to negative emotions over the right hemisphere. Detection of the target smiling faces was evident in the increased amplitude of the frontal and central P3 responses but only for inverted smiling faces.

Conclusion

Persons with the mUPD subtype of PWS may show atypical face versus object processes, yet both subtypes demonstrated potentially altered processing, attention to and/or recognition of faces and their expressions.     

I spy with my little eye: The detection of changes in emotional faces and the influence of facial feedback in Parkinson disease

Background and purpose

Parkinson disease (PD) is a progressive neurodegenerative disorder that affects the motor system but also involves deficits in emotional processing such as facial emotion recognition. In healthy participants, it has been shown that facial mimicry, the automatic imitation of perceived facial expressions, facilitates the interpretation of the emotional states of our counterpart. In PD patients, recent studies revealed reduced facial mimicry and consequently reduced facial feedback, suggesting that this reduction might contribute to the prominent emotion recognition deficits found in PD.

Methods

We investigated the influence of facial mimicry on facial emotion recognition. Twenty PD patients and 20 healthy controls (HCs) underwent a classical facial mimicry manipulation (holding a pen with the lips, teeth, or nondominant hand) while performing an emotional change detection task with faces.

Results

As expected, emotion recognition was significantly influenced by facial mimicry manipulation in HCs, further supporting the hypothesis of facial feedback and the related theory of embodied simulation. Importantly, patients with PD, generally and independent from the facial mimicry manipulation, were impaired in their ability to detected emotion changes. Our data further show that PD patients' facial emotional recognition abilities are completely unaffected by mimicry manipulation, suggesting that PD patients cannot profit from an artificial modulation of the already impaired facial feedback.

Conclusions

These findings suggest that it is not the hypomimia and the absence of facial feedback per se, but a disruption of the facial feedback loop, that leads to the prominent emotion recognition deficit in PD patients.     

Patterns of brain asymmetry in the perception of positive and negative facial expressions

The divided visual field technique was used to investigate the pattern of brain asymmetry in the perception of positive/approach and negative/withdrawal facial expressions. A total of 80 undergraduate students (65 female, 15 male) were distributed in five experimental groups in order to investigate separately the perception of expressions of happiness, surprise, fear, sadness, and the neutral face. In each trial a target and a distractor expression were presented simultaneously in a computer screen for 150 ms and participants had to determine the side (left or right) on which the target expression was presented. Results indicated that expressions of happiness and fear were identified faster when presented in the left visual field, suggesting an advantage of the right hemisphere in the perception of these expressions. Fewer judgement errors and faster reaction times were also observed for the matching condition in which emotional faces were presented in the left visual field and neutral faces in the right visual field. Other results indicated that positive expressions (happiness and surprise) were perceived faster and more accurately than negative ones (sadness and fear). Main results tend to support the right hemisphere hypothesis, which predicts a better performance of the right hemisphere to perceive emotions, as opposed to the approach–withdrawal hypothesis.     

Hemispheric differences in recognition of facial expressions: a VHF-study of negative, positive, and neutral emotions

The present study was concerned with a tachistoscopic investigation of asymmetry of recognition of different facial emotional expressions. Twenty-eight subjects had nine different drawings of facial expressions (either positive, negative, or neutral in emotional content) presented either to the left or right visual half-field. Recognition of the correct face was made for each stimulus-presentation. The results showed overall better recognition for presentations in the left half-field (LVF) (i.e., right hemisphere) compared to right half-field (RVF) (i.e., left hemisphere) presentations. Furthermore, while all three emotional categories were recognized about equally well in the right half-field, positive emotional expressions were significantly better than the neutral and negative categories when presented to the left half-field. The results are discussed in relation to previous findings of cerebral asymmetry in processing of emotional facial expressions.