Lateralisation for processing facial emotion and anxiety: contrasting state, trait and social anxiety

Recent neuropsychological studies have attempted to distinguish between different types of anxiety by contrasting patterns of brain organisation or activation; however, lateralisation for processing emotional stimuli has received relatively little attention. This study examines the relationship between strength of lateralisation for the processing of facial expressions of emotion and three measures of anxiety: state anxiety, trait anxiety and social anxiety. Across all six of the basic emotions (anger, disgust, fear, happiness, sadness, surprise) the same patterns of association were found. Participants with high levels of trait anxiety were more strongly lateralised to the right hemisphere for processing facial emotion. In contrast, participants with high levels of self-reported physiological arousal in response to social anxiety were more weakly lateralised to the right hemisphere, or even lateralised to the left hemisphere, for the processing of facial emotion. There were also sex differences in these associations: the relationships were evident for males only. The finding of distinct patterns of lateralisation for trait anxiety and self-reported physiological arousal suggests different neural circuitry for trait and social anxiety.     

Examining the effects of inversion on lateralisation for processing facial emotion

There is an increasing amount of evidence which suggests that each hemisphere is differently specialised for processing facial stimuli, with the right hemisphere specialised for the processing of configural information and the left hemisphere specialised for the processing of featural information. While there is evidence for this distinction from studies of face recognition, it has not been shown in studies of lateralisation for processing facial emotion. In this study the chimeric faces test was used with faces expressing anger, disgust, fear, happiness, sadness or surprise, presented in either an upright or an inverted orientation. When presented upright, a significant right hemisphere bias was found for all six emotions. However, when inverted, a significant left hemisphere bias was found for the processing of happiness and surprise, but not for the processing of negative emotions (although the analysis was approaching significance for anger). These findings support the hypothesis that each hemisphere is differently specialised for processing facial emotion, but contradicts previous work that examined the effects of inversion on chimeric face stimuli.     

Examining the relationship between lateralisation for processing emotional faces,depression, and sex

It is now relatively well established that the right hemisphere is specialised for processing facial emotion; however, there is variability in this pattern of lateralisation. One factor that has been examined is atypical lateralisation in individuals diagnosed with clinical psychological conditions. To date the evidence regarding the neuropsychological processing of emotional stimuli in individuals with depression is contradictory. In this study 160 participants completed the Beck Depression Inventory and the chimeric faces test, a test of lateralisation for the processing of facial expressions of each of the six basic emotions. A negative relationship between depression and lateralisation was found for females only, showing that women with higher depression scores tend to be less strongly lateralised to the right hemisphere, or even lateralised to the left hemisphere, for processing facial emotion. The strength of this relationship also varied across the different emotions with the clearest results for the processing of anger, disgust, and fear. There were no significant findings for males. The possible reasons for there being a sex difference in our findings and an attempt to reconcile the disparate findings within this area of research are discussed.     

Selective Impairment of Basic Emotion Recognition in People with Autism: Discrimination Thresholds for Recognition of Facial Expressions of Varying Intensities

Autism spectrum disorders (ASD) are characterized by early onset qualitative impairments in reciprocal social development. However, whether individuals with ASD exhibit impaired recognition of facial expressions corresponding to basic emotions is debatable. To investigate subtle deficits in facial emotion recognition, we asked 14 children diagnosed with high-functioning autism (HFA)/AS and 17 typically developing peers to complete a new highly sensitive test of facial emotion recognition. The test stimuli comprised faces expressing increasing degrees of emotional intensity that slowly changed from a neutral to a full-intensity happiness, sadness, surprise, anger, disgust, or fear expression. We assessed individual differences in the intensity of stimuli required to make accurate judgments about emotional expressions. We found that, different emotions had different identification thresholds and the two groups were generally similar in terms of the sequence of discrimination threshold of six basic expressions. It was easier for individuals in both groups to identify emotions that were relatively fully expressed (e.g., intensity >?50%). Compared with control participants, children with ASD generally required stimuli with significantly greater intensity for the correct identification of anger, disgust, and fear expressions. These results suggest that individuals with ASD do not have a general but rather a selective impairment in basic emotion recognition.     

Strength of lateralisation for processing facial emotion in relation to autistic traits in individuals without autism

A great number of studies have shown that non-clinical individuals rely predominantly on the right hemisphere to process facial emotion. Previous studies have shown that males suffering from Asperger's syndrome show a typical right hemisphere bias for processing facial emotion (happiness and sadness) but a reduced right hemisphere bias for processing facial identity. This study looks at the lateralisation of all six basic emotions using the chimeric faces test in 64 non-clinical participants (32 males, 32 females) and correlates it with their autistic traits measured using the Broad Autistic Phenotype Questionnaire. For males only, regression analyses showed a relationship between the aloof personality trait and lateralisation for fear, happiness, and surprise. Males with high autistic scores on the aloof personality subscale (showing a lack of interest in social interaction) were more strongly lateralised to the right hemisphere for processing fear, happiness, and surprise. For males there was no relationship with anger, disgust, sadness, or non-facial stimuli, and for females there were no significant relationships at all. The autistic traits of rigidity and pragmatic language were not significant predictors of emotion lateralisation. The over-reliance on the right hemisphere for processing facial emotion in males seems to support the idea that the autistic brain could be seen as hyper-masculinised, possibly due to prenatal testosterone exposure.     

Perception of emotional facial expressions at different intensities in early-symptomatic Huntington's disease

BACKGROUND: While there is abundant evidence that patients with Huntington's disease (HD) have an impairment in the recognition of the emotional facial expression of disgust, previous studies have only examined emotion perception using full-blown facial expressions. OBJECTIVE: The current study examines the perception of facial emotional expressions in HD at different levels of intensity to investigate whether more subtle deficits can be detected, possible also in other emotions. METHOD: We compared early symptomatic HD patients with healthy matched controls on emotion perception, presenting short video clips of a neutral face changing into one of the six basic emotions (happiness, anger, fear, surprise, disgust and sadness) with increasing intensity. Overall face perception ability as well as depressive symptoms were taken into account. RESULTS: A specific impairment in recognizing the emotions disgust and anger was found, which was present even at low emotion intensities. CONCLUSION: These results extend previous findings and support the use of more sensitive emotion perception paradigms, which enable the detection of subtle neurobehavioral deficits even in the pre- and early symptomatic stages of the disease.     

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.     

Impaired facial expression recognition in children with temporal lobe epilepsy: impact of early seizure onset on fear recognition

The amygdala has been implicated in the recognition of facial emotions, especially fearful expressions, in adults with early-onset right temporal lobe epilepsy (TLE). The present study investigates the recognition of facial emotions in children and adolescents, 8–16 years old, with epilepsy. Twenty-nine subjects had TLE (13 right, 16 left) and eight had fronto-central epilepsy (FCE). Each was matched on age and gender with a control subject. Subjects were asked to label the emotions expressed in pictures of children's faces miming five basic emotions (happiness, sadness, fear, disgust and anger) or neutrality (no emotion). All groups of children with epilepsy performed less well than controls. Patterns of impairment differed according to the topography of the epilepsy: the left-TLE (LTLE) group was impaired in recognizing fear and neutrality, the right-TLE (RTLE) group was impaired in recognizing disgust and, the FCE group was impaired in recognizing happiness. We clearly demonstrated that early seizure onset is associated with poor recognition of facial expression of emotion in TLE group, particularly for fear. Although right-TLE and left-TLE subjects were both impaired in the recognition of facial emotion, their psychosocial adjustment, as measured by the CBCL questionnaire [Achenbach, T. M. (1991). Manual for the Child Behavior Checklist and Youth Self-report. Burlington, VT: University of Vermont Department of Psychiatry], showed that poor recognition of fearful expressions was related to behavioral disorders only in children with right-TLE. Our study demonstrates for the first time that early-onset TLE can compromise the development of recognizing facial expressions of emotion in children and adolescents and suggests a link between impaired fear recognition and behavioral disorders.     

Processing of emotional facial expressions in Korsakoff's syndrome

Interpersonal contacts depend to a large extent on understanding emotional facial expressions of others. Several neurological conditions may affect proficiency in emotional expression recognition. It has been shown that chronic alcoholics are impaired in labelling emotional expressions. More specifically, they mislabel sad expressions, regarding them as more hostile. Surprisingly, there has been relatively little research on patients with Korsakoff's syndrome as a result of chronic alcohol abuse. The current study investigated 23 patients diagnosed with Korsakoff's syndrome compared to 23 matched control participants. This study is the first to make use of a newly developed sensitive paradigm to measure emotion recognition for several emotions (anger, disgust, fear, happiness, sadness and surprise). The results show that patients with Korsakoff's syndrome are impaired at recognizing angry, fearful and surprised facial emotional expressions. These deficits might be due to the reported sub-cortical brain dysfunction in Korsakoff's syndrome.     

Defective emotion recognition in early HD is neuropsychologically and anatomically generic

Huntington's disease (HD) is an inherited neurodegenerative disorder that classically presents with motor, cognitive and psychiatric symptoms. However, other abnormalities also occur in this condition, notably deficient recognition of facial emotional expressions. Deficits in emotion recognition impact significantly on the lives of HD patients and their families and thus it is important to clarify the onset and pattern of impairment. This study investigated facial emotion recognition in a large cohort of early HD patients, and premanifest gene-carriers. We used voxel-based morphometry (VBM) to examine the neuroanatomical correlates of emotion recognition performance. Forty patients with early HD, 21 premanifest gene carriers and 20 controls were assessed using 24 faces from the Ekman Pictures of Facial Affect, and volumetric brain MRI. The HD group was significantly worse than controls at recognising, surprise, disgust, anger and fear, and worse than the premanifest group at recognising disgust and anger. When patient data were expressed as z-scores, recognition of anger was significantly worse than disgust in the early HD group. In the VBM analysis, these deficits were associated with common regional atrophy: impaired recognition of surprise, disgust, anger and fear were all associated with striatal volume loss. Fear was associated with additional atrophy of the right insula and left and right lateral orbitofrontal cortex. Even in early HD there is a wide-ranging impairment in recognition of negative emotions denoting 'threat'. Our findings implicate a generic fronto-subcortical network in the pathogenesis of these emotion recognition deficits.     

Mixed emotions: alcoholics' impairments in the recognition of specific emotional facial expressions

Facial expression recognition is a central feature of emotional and social behaviour and previous studies have found that alcoholics are impaired in this skill when presented with single emotions of differing intensities. The aim of this study was to explore biases in alcoholics' recognition of emotions when they were a mixture of two closely related emotions. The amygdala is intimately involved in encoding of emotions, especially those related to fear. In animals an increased number of withdrawals from alcohol leads to increased seizure sensitivity associated with facilitated transmission in the amygdala and related circuits. A further objective therefore was to explore the effect of previous alcohol detoxifications on the recognition of emotional facial expressions. Fourteen alcoholic inpatients were compared with 14 age and sex matched social drinking controls. They were asked to rate how much of each of six emotions (happiness, surprise, fear, sadness, disgust and anger) were present in morphed pictures portraying a mix of two of those emotions. The alcoholic group showed enhanced fear responses to all of the pictures compared to the controls and showed a different pattern of responding on anger and disgust. There were no differences between groups on decoding of sad, happy and surprised expressions. In addition the enhanced fear recognition found in the alcoholic group was related to the number of previous detoxifications. These results provide further evidence for impairment in facial expression recognition present in alcoholic patients. In addition, since the amygdala has been associated with the processing of facial expressions of emotion, particularly those of fear, the present data furthermore suggest that previous detoxifications may be related to changes within the amygdala.     

Emotional facial expressive and discriminative performance and lateralization in normal young adults

Studies of cerebral dominance for posed emotional facial expression using free-viewing of hemicomposites have produced inconclusive findings, and the concordance of facial emotion identification (discrimination) and the expression of the same facial emotion remains unknown. Expressive and discriminative (14 men, 14 women) facial emotion performances of undergraduates and the lateralization of full-face and lower-face hemicomposite photographic montages of the expressions of six transcultural emotions (joy, sadness, fear, surprise, disgust, anger) as ascertained by 15 male and 15 female undergraduate judges were analyzed. All groups were matched for age and education. The lower face was non-significantly left-face dominant, sadness was strongly significantly right-face dominant and fear was non-significantly left face dominant. Both sexes were equally lateralized overall and demonstrated the same pattern as described above, though slight (apparently trivial) differences appeared in multivariate analysis, and in univariate interactions. Results were interpreted as non-supportive of a simple right hemisphere dominance model of facial affect, nor of a left-hemisphere-negative/right-hemisphere-positive model. It was concluded that facial affect dominance results are coherent only within, and not between, methods such as free viewing hemicomposite and tachistoscopic methods, and tasks, such as expressive and discriminative tasks.     

Explicit identification and implicit recognition of facial emotions: I. Age effects in males and females across 10 decades

A number of psychiatric and neurological disorders are characterized by impairments in facial emotion recognition. Recognition of individual emotions has implicated limbic, basal ganglionic, and frontal brain regions. Since these regions are also implicated in age-related decline and sex differences in emotion processing, an understanding of normative variation is important for assessing deficits in clinical groups. An internet-based test ("WebNeuro") was administered to 1,000 healthy participants (6 to 91 years, 53% female) to assess explicit identification of basic expressions of emotion (happiness, sadness, fear, anger, disgust, neutral). A subsequent implicit recognition condition was based on a priming protocol, in which explicit identification provided the "study" phase. Responses were most accurate for happiness and slowest for fear in the explicit condition, but least accurate for happiness and fastest for fear in the implicit condition. The effects of age, by contrast, showed a similar pattern for both explicit and implicit conditions, following a nonlinear distribution in which performance improved from childhood through adolescence and early adulthood and declined in later adulthood. Females were better than males at explicit identification of fear in particular. These findings are consistent with the priority of threat-related signals, but indicate opposing biases depending on whether emotion processing is conscious or nonconscious. The lifespan trends in emotion processing over 10 decades point to an interaction of brain-based (maturation, stability, and then atrophy of cortical and subcortical systems) and experiential contributing factors. These findings provide a robust normative platform for assessing clinical groups.     

BIS/BAS, cortical oscillations and coherence in response to emotional cues

The present study explored the effect of the individual differences related to BIS and BAS (Behavioural Inhibition and Activation System) on brain oscillations, in response to appetitive and aversive emotional stimuli. EEG cortical measures (delta, theta, alpha, and gamma) were recorded, during viewing IAPS figures, that varied in terms of pleasantness and arousal. Withdrawal (BIS system) and appetitive (BAS system) behaviour showed opposite patterns of subjective responses. Also, a specific frontal network was found to be responsive to the relevance of emotional cues. Moreover an increased response for high arousing (negative and positive) stimuli in comparison with low arousing and neutral stimuli was found within the left and right frontal areas. Specifically delta and theta band have a significant role in monitoring the attentional significance of emotions. Finally, the effects of subjective evaluation and individual differences were discussed at light of the two-dimensional model of emotion processing, that is the valence and the arousing power of emotional cues.     

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.     

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.     

Effects of lesion variables and emotion type on the perception of facial emotion.

The purpose of this study was to consider the effects of valence, motoric direction (i.e., approach/withdrawal), and arousal on the perception of facial emotion in patients with unilateral cortical lesions. We also examined the influence of lesion side, site, and size on emotional perception. Subjects were 30 right-hemisphere-damaged (RHD) and 30 left-hemisphere-damaged (LHD) male patients with focal lesions restricted primarily to the frontal, temporal, or parietal lobe. Patient groups were comparable on demographic and clinical neurological variables. Subjects were tested for their ability to match photographs of four facial emotional expressions: happiness, sadness, fear, and anger. Overall, RHD patients were significantly more impaired than LHD patients in perceiving facial emotion. Lesion side, but not site, was associated with motoric direction and valence dimensions. RHD patients had specific deficits relative to LHD patients in processing negative and withdrawal emotions; there were no group differences for positive/approach emotions. Lesion size was not significantly correlated with accuracy of emotional perception.     

BESST (Bochum Emotional Stimulus Set)—A pilot validation study of a stimulus set containing emotional bodies and faces from frontal and averted views

This article introduces the freely available Bochum Emotional Stimulus Set (BESST), which contains pictures of bodies and faces depicting either a neutral expression or one of the six basic emotions (happiness, sadness, fear, anger, disgust, and surprise), presented from two different perspectives (0° frontal view vs. camera averted by 45° to the left). The set comprises 565 frontal view and 564 averted view pictures of real-life bodies with masked facial expressions and 560 frontal and 560 averted view faces which were synthetically created using the FaceGen 3.5 Modeller. All stimuli were validated in terms of categorization accuracy and the perceived naturalness of the expression. Additionally, each facial stimulus was morphed into three age versions (20/40/60 years). The results show high recognition of the intended facial expressions, even under speeded forced-choice conditions, as corresponds to common experimental settings. The average naturalness ratings for the stimuli range between medium and high.