The expression and perception of facial emotion in brain-damaged patients

Apragmatism: The renewal of a label for communication disorders associated with right hemisphere brain damage

BACKGROUND

Right hemisphere communication disorders are neither consistently labelled nor adequately defined. Labels associated with right hemisphere brain damage (RHD) are broad and fail to capture the essence of communication challenges needed for stroke-related service provisions. Determination of rehabilitation needs and best-practice guidelines for the education, management and functional improvement of communication disorders after RHD are all predicated on an apt diagnostic label and disorder characteristics.

AIMS

In this paper apragmatism is proposed as a potential communication-specific diagnostic label for the impairments in communication that occur after RHD. In particular, the researchers aimed: (1) to establish an operational definition of apragmatism; and (2) to describe the linguistic, paralinguistic and extralinguistic communication deficits under the umbrella term apragmatism.

METHODS & PROCEDURES

An international collaborative of researchers with expertise in RHD followed a multilevel approach to consider the utility of apragmatism as a diagnostic label. Adopting the relational approach to concept mapping, the researchers engaged in a series of group meetings to complete four levels of mapping: (1) identify and review, (2) define, (3) expert discussion and (4) label determination.

MAIN CONTRIBUTION

Apragmatism was established as a suitable diagnostic label for the impairments in communication associated with RHD. The paper offers an operational definition and description of the linguistic, paralinguistic and extralinguistic features of apragmatism through evidence summaries and examples from people with RHD retrieved from the RHDBank.

CONCLUSIONS & IMPLICATIONS

The adoption of the term apragmatism offers an opportunity to capture the hallmark of RHD communication deficits. The use of the term is recommended when referencing the pragmatic language impairments in this population. Apragmatism, which may co-occur with or be exacerbated by cognitive impairments, can interfere with the ability to interpret and convey intended meaning and impact the lives of right hemisphere stroke survivors and their families.

WHAT THIS PAPER ADDS

What is already known on the subject RHD results in a heterogeneous group of deficits that range in cognitive-communicative complexity. Many of the deficits are subsumed under pragmatics. For example, adults with RHD may demonstrate tangential or verbose communication, insensitivity to others' needs and feelings, prosodic changes, minimal gesture use and facial expression, and more. While descriptions of pragmatic impairments pervade the literature, there is no consistently used diagnostic label. The clinical consequences of this absence include difficulty with inter- and intra-disciplinary communication about these patients, difficulty consolidating findings across research studies, and challenges in communicating about these pragmatic changes with patients, families and other stakeholders. What this paper adds to existing knowledge The term apragmatism is proposed as a diagnostic label to consistently describe pragmatic communication changes after RHD. Apragmatism is characterized using three components of pragmatics: linguistic, paralinguistic and extralinguistic. Descriptions and examples of these three components are provided with supplemental transcripts retrieved from the RHDBank. What are the potential or actual clinical implications of this work? Adoption of the term apragmatism by speech and language therapists and other medical and rehabilitation professionals has the potential to provide consistency in describing the abilities and challenges experienced by people following a right hemisphere stroke. Such improvements may help drive the development of evidence-based assessments and treatments for this population.

Some historical notes orienting towards brain mechanisms that could underlie hemispheric asymmetries

The first minor aim of this synthetical historical survey consisted in showing that the discovery of the internal organization of language within the left hemisphere has been mainly determined by theoretical models and cultural factors, whereas the discovery of the left lateralisation of language and of the right lateralization of emotions and of other cognitive and perceptual functions has been mainly determined by empirical observations. A second more relevant aim of the survey consisted in discussing historical and more recent data suggesting that the different lateralisation of language and emotions has influenced not only the asymmetrical representation of other cognitive, affective and perceptual functions, but also (thank to the shaping influence of language on human cognition) of asymmetries regarding more general aspects of thought (such as the distinctions between 'propositional vs automatic' and 'conscious vs unconscious' ways of functioning). In the last part of the review, these data will be included in a more general discussion, concerning the brain functions that could be subsumed by the right hemisphere for three main reasons: (a) to avoid conflicts with the language mediated activities of the left hemisphere; (b) because of unconscious and automatic aspects of its non-verbal organisation or (c) due to the competition for cortical space determined by the development of language within the left hemisphere.

Laterality of motor symptom onset and facial expressivity in Parkinson disease using face digitization

The onset of motor symptoms in Parkinson disease (PD) is typically unilateral. Previous work has suggested that laterality of motor symptoms may also influence non-motor symptoms including cognition and emotion perception. In line with hemispheric differences in emotion processing, we tested whether left side/right brain motor onset was associated with worse expression of facial affect when compared to right side/left brain motor onset. We evaluated movement changes associated with facial affect in 30 patients with idiopathic PD (15 left-sided motor onset, 15 right-sided motor onset) and 20 healthy controls. Participants were videotaped while posing three facial expressions: fear, anger, and happiness. Expressions were digitized and analyzed using software that extracted three variables: two measures of dynamic movement change (total entropy and entropy percent change) and a measure of time to initiate facial expression (latency). The groups did not differ in overall amount of movement change or percentchange. However, left-sided onset PD patients were significantly slower in initiating anger and happiness facial expressions than were right-sided onset PD patients and controls. Our results indicated PD patients with left-sided symptom onset had greater latency in initiating two of three facial expressions, which may reflect laterality effects in intentional behaviour.

Psychiatric sequelae of stroke affecting the non-dominant cerebral hemisphere

There are a plethora of cognitive sequelae in addition to neglect and extinction that arise with unilateral right hemispheric stroke (RHS). Cognitive deficits following non-dominant (right) hemisphere stroke are common with unilateral neglect and extinction being the most recognized examples. The severity of RHS is usually underestimated by the National Institutes of Health Stroke Scale (NIHSS), which in terms of lateralized right hemisphere cognitive deficits, tests only for visual inattention/extinction. They account for 2 out of 42 total possible points. Additional neuropsychiatric sequelae include but are not limited to deficiencies in affective prosody comprehension and production (aprosodias), understanding and expressing facial emotions, empathy, recognition of familiar faces, anxiety, mania, apathy, and psychosis. These sequelae have a profound impact on patients' quality of life; affecting communication, interpersonal relationships, and the ability to fulfill social roles. They also pose additional challenges to recovery. There is presently a gap in the literature regarding a cohesive overview of the significant cognitive sequelae following RHS. This paper serves as a narrative survey of the current understanding of the subject, with particular emphasis on neuropsychiatric poststroke syndromes not predominantly associated with left hemisphere lesions (LHL), bilateral lesions, hemiplegia, or paralysis. A more comprehensive understanding of the neuropsychological consequences of RHS extending beyond the typical associations of unilateral neglect and extinction may have important implications for clinical practice, including the ways in which clinicians approach diagnostics, treatment, and rehabilitation.

Identifying spatial effects in a lateralized duration estimation task

Spatial influences may be introduced to an experimental task by manipulations performed on the stimulus or the response or by virtue of the type of stimuli under study. Identification of spatial influences is especially pertinent in investigations of laterality, as isolation of processing to one hemisphere may inadvertently introduce spatial confounds. Because, however, space is not a relevant task feature, it may not always be obvious that it should be taken into consideration. Failure to anticipate these spatial influences can affect the conclusions drawn from results. The current work examines potential spatial influences in an experimental paradigm previously used to investigate perceptual asymmetries for duration estimation in which both stimulus presentation and response selection were lateralized. Potential spatial influences (including the spatial-temporal association of response codes - STEARC, spatial attention, and the Simon effect) are identified and systematically tested over 5 experiments. Results suggest that previously observed perceptual asymmetries in this experimental paradigm may be the result of a spatial confound, specifically, that of the Simon effect. Using vertical response options with the lateral stimulus presentation, however, mitigated the spatial influence. Altogether, the current work demonstrates the importance of carefully considering potential spatial confounds prior to commencement of laterality studies.

At the Neural Intersection Between Language and Emotion

What role does language play in emotion? Behavioral research shows that emotion words such as "anger" and "fear" alter emotion experience, but questions still remain about mechanism. Here, we review the neuroscience literature to examine whether neural processes associated with semantics are also involved in emotion. Our review suggests that brain regions involved in the semantic processing of words: (i) are engaged during experiences of emotion, (ii) coordinate with brain regions involved in affect to create emotions, (iii) hold representational content for emotion, and (iv) may be necessary for constructing emotional experience. We relate these findings with respect to four theoretical relationships between language and emotion, which we refer to as "non-interactive," "interactive," "constitutive," and "deterministic." We conclude that findings are most consistent with the interactive and constitutive views with initial evidence suggestive of a constitutive view, in particular. We close with several future directions that may help test hypotheses of the constitutive view.

A Voxel-based lesion study on facial emotion recognition after circumscribed prefrontal cortex damage

Previous studies have shown inconsistent findings regarding the contribution of the different prefrontal regions in emotion recognition. Moreover, the hemispheric lateralization hypothesis posits that the right hemisphere is dominant for processing all emotions regardless of affective valence, whereas the valence specificity hypothesis posits that the left hemisphere is specialized for processing positive emotions while the right hemisphere is specialized for negative emotions. However, recent findings suggest that the evidence for such lateralization has been less consistent. In this study, we investigated emotion recognition of fear, surprise, happiness, sadness, disgust, and anger in 30 patients with focal prefrontal cortex lesions and 30 control subjects. We also examined the impact of lesion laterality on recognition of the six basic emotions. The results showed that compared to control subjects, the frontal subgroups were impaired in recognition of three negative basic emotions of fear, sadness, and anger - regardless of the lesion laterality. Therefore, our findings did not establish that each hemisphere is specialized for processing specific emotions. Moreover, the voxel-based lesion symptom mapping analysis showed that recognition of fear, sadness, and anger draws on a partially common bilaterally distributed prefrontal network.

Disorders of facial emotional expression and comprehension

One of the most important means of communicating emotions is by facial expressions. About 30-40 years ago, several studies examined patients with right and left hemisphere strokes for deficits in expressing and comprehending emotional facial expressions. The participants with right- or left-hemispheric strokes attempted to determine if two different actors were displaying the same or different emotions, to name the different emotions being displayed, and to select the face displaying an emotion named by the examiner. Investigators found that the right hemisphere-damaged group was impaired on all these emotional facial tests and that this deficit was not solely related to visuoperceptual processing defects. Further studies revealed that the patients who were impaired at recognizing emotional facial expressions and who had lost these visual representations of emotional faces often had damage to their right parietal lobe and their right somatosensory cortex. Injury to the cerebellum has been reported to impair emotional facial recognition, as have dementing diseases such as Alzheimer's disease and frontotemporal dementia, movement disorders such as Parkinson's disease and Huntington's disease, traumatic brain injuries, and temporal lobe epilepsy. Patients with right hemisphere injury are also more impaired than left-hemisphere-damaged patients when attempting to voluntarily produce facial emotional expressions and in their spontaneous expression of emotions in response to stimuli. This impairment does not appear to be induced by emotional conceptual deficits or an inability to experience emotions. Many of the disorders that cause impairments of comprehension of affective facial expressions also impair facial emotional expression. Treating the underlying disease may help patients with impairments of facial emotion recognition and expression, but unfortunately, there have not been many studies of rehabilitation.

Siamese Architecture-Based 3D DenseNet with Person-Specific Normalization Using Neutral Expression for Spontaneous and Posed Smile Classification

Clinical studies have demonstrated that spontaneous and posed smiles have spatiotemporal differences in facial muscle movements, such as laterally asymmetric movements, which use different facial muscles. In this study, a model was developed in which video classification of the two types of smile was performed using a 3D convolutional neural network (CNN) applying a Siamese network, and using a neutral expression as reference input. The proposed model makes the following contributions. First, the developed model solves the problem caused by the differences in appearance between individuals, because it learns the spatiotemporal differences between the neutral expression of an individual and spontaneous and posed smiles. Second, using a neutral expression as an anchor improves the model accuracy, when compared to that of the conventional method using genuine and imposter pairs. Third, by using a neutral expression as an anchor image, it is possible to develop a fully automated classification system for spontaneous and posed smiles. In addition, visualizations were designed for the Siamese architecture-based 3D CNN to analyze the accuracy improvement, and to compare the proposed and conventional methods through feature analysis, using principal component analysis (PCA).

A conceptual critique of brain lateralization models in emotional face perception: Toward a hemispheric functional-equivalence (HFE) model

The present review proposes a novel dynamic model of brain lateralization of emotional (happy, surprised, fearful, sad, angry, and disgusted) and neutral face perception. Evidence to date suggests that emotional face perception is lateralized in the brain. At least five prominent hypotheses of the lateralization of emotional face perception have been previously proposed; the right-hemisphere hypothesis; the valence-specific hypothesis; the modified valence-specific hypothesis; the motivational hypothesis; and behavioral activation/inhibition system hypothesis. However, a growing number of recent replication studies exploring those hypotheses frequently provide inconsistent or even contradictory results. The latest neuroimaging and behavioral studies strongly demonstrate the functional capacity of both hemispheres to process emotions relatively successfully. Moreover, the flexibility of emotional brain-networks in both hemispheres is functionally high even to the extent of a possible reversed asymmetry of the left and the right hemisphere performance under altered neurophysiological and psychological conditions. The present review aims to a) provide a critical conceptual analysis of prior and current hypotheses of brain lateralization of emotional and neutral face perception; b) propose an integrative introduction of a novel hemispheric functional-equivalence (HFE) model in emotional and neutral face perception based on the evaluation of theoretical considerations, behavioral and neuroimaging studies: the brain is initially right-biased in emotional and neutral face perception by default; however, altered psychophysiological conditions (e.g., acute stress, a demanding emotional task) activate a distributed brain-network of both hemispheres toward functional equivalence that results in relatively equalized behavioral performance in emotional and neutral face perception. The proposed novel model may provide a practical tool in further experimental investigation of brain lateralization of emotional face perception.

Assessing Self-Reported Mood in Aphasia Following Stroke: Challenges, Innovations and Future Directions

Assessment of mood is critical in determining rehabilitation outcomes for stroke and other acquired brain injury, yet a common consequence of such injuries is aphasia, where language is impaired. Consequently, the use of language-based measures in this population is often not possible. Following a critical review of the neuropsychological aspects of self-reported mood, this paper evaluates the problems in reporting mood after stroke due to aphasia, and discusses implications for the design of adapted instruments. The paper then appraises the construction and psychometric properties of existing, adapted self-report measures developed to try and address these problems, and evaluates their utility and limitations. This includes a focus on the recently validated tablet-based Dynamic Visual Analog Mood Scales (D-VAMS), which uses innovative non-verbal assessment methods based on facial expression modulated via a slider control on a touchscreen interface. Currently, most studies evaluating recovery interventions simply omit individuals with aphasia because of the difficulty of assessing mood and quality of life in this population. However, adapted scales such as the D-VAMS appear to represent an important step forward in assessing mood in people with language impairments, with the use of interactive modulated imagery having wider applications for nonverbal communication as well as the quantification of subjective phenomena.

Retinotopy of emotion: Perception of negatively valenced stimuli presented at different spatial locations as revealed by event-related potentials

Scarce previous data on how the location where an emotional stimulus appears in the visual scene modulates its perception suggest that, for functional reasons, a perceptual advantage may exist, vertically, for stimuli presented at the lower visual field (LoVF) and, horizontally, for stimuli presented at the left visual field (LeVF). However, this issue has been explored through a limited number of spatial locations, usually in a single spatial dimension (e.g., horizontal) and invariant eccentricities. Event-related potentials (ERPs) were recorded from 39 participants perceiving brief neutral (wheels) and emotional stimuli (spiders) presented at 17 different locations, one foveal and 16 at different peripheral coordinates. As a secondary scope, we explored the role of the magnocellular (M) and the parvocellular (P) visual pathways by presenting an isoluminant/heterochromatic (P-biased) and a heteroluminant/isochromatic version (M-biased) of each stimulus. Emo > Neu effects were observed in PN1 (120 ms) for stimuli located at fovea, and in PN2 (215 ms) for stimuli located both at fovea and diverse peripheral regions. A factorial approach to these effects further revealed that: (a) emotional stimuli presented in the periphery are efficiently perceived, without evident decrease from para- to perifovea; (b) peripheral Emo > Neu effects are reflected 95 ms later than foveal Emo > Neu effects in ERPs; (c) LoVF is more involved than UVF in these effects; (d) our data fail to support the LeVF advantage previously reported, and (e) Emo > Neu effects were significant for both M and P stimuli.

A historical review of investigations on laterality of emotions in the human brain

Different models of emotional lateralization, advanced since the first clinical observations raised this issue, will be reviewed following their historical progression. The clinical investigations that have suggested a general dominance of the right hemisphere for all kinds of emotions and the experimental studies that have proposed a different hemispheric specialization for positive vs. negative emotions (valence hypothesis) or for approach vs. withdrawal tendencies (motivational hypothesis) will be reviewed first and extensively. This historical review will be followed by a short discussion of recent anatomo-clinical and activation studies that have investigated (a) emotional and behavioral disorders of patients with asymmetrical forms of fronto-temporal degeneration and (b) laterality effects in specific brain structures (amygdala, ventro-medial prefrontal cortex, and anterior insula) playing a critical role in different components of emotions. Overall, these studies support the hypothesis of a right hemisphere dominance for all components of the emotional system.

Emotions and the Right Hemisphere: Can New Data Clarify Old Models?

Models advanced to explain hemispheric asymmetries in representation of emotions will be discussed following their historical progression. First, the clinical observations that have suggested a general dominance of the right hemisphere for all kinds of emotions will be reviewed. Then the experimental investigations that have led to proposal of a different hemispheric specialization for positive versus negative emotions (valence hypothesis) or, alternatively, for approach versus avoidance tendencies (motivational hypothesis) will be surveyed. The discussion of these general models will be followed by a review of recent studies which have documented laterality effects within specific brain structures, known to play a critical role in different components of emotions, namely the amygdata in the computation of emotionally laden stimuli, the ventromedial prefrontal cortex in the integration between cognition and emotion and in the control of impulsive reactions and the anterior insula in the conscious experience of emotion. Results of these recent investigations support and provide an updated integrated version of early models assuming a general right hemisphere dominance for all kinds of emotions.

Emotions Are Rising: The Growing Field of Affect Neuropsychology

Thirty years ago, the neuropsychology of emotion started to emerge as a mainstream topic. Careful examination of individual patients showed that emotion, like memory, language, and so on, could be differentially affected by brain disorders, especially in the right hemisphere. Since then, there has been accelerating interest in uncovering the neural architecture of emotion, and the major steps in this process of discovery over the past 3 decades are detailed in this review. In the 1990s, magnetic resonance imaging (MRI) scans provided precise delineation of lesions in the amygdala, medial prefrontal cortex, insula and somatosensory cortex as underpinning emotion disorders. At the same time, functional MRI revealed activation that was bilateral and also lateralized according to task demands. In the 2000s, converging evidence suggested at least two routes to emotional responses: subcortical, automatic and autonomic responses and slower, cortical responses mediating cognitive processing. The discovery of mirror neurons in the 1990s reinvigorated older views that simulation was the means to recognize emotions and empathize with others. More recently, psychophysiological research, revisiting older Russian paradigms, has contributed new insights into how autonomic and other physiological indices contribute to decision making (the somatic marker theory), emotional simulation, and social cognition. Finally, this review considers the extent to which these seismic changes in understanding emotional processes in clinical disorders have been reflected in neuropsychological practice. (JINS, 2017, 23, 719-731).

Processing of Unattended Emotional Facial Expressions: Correlates of Visual Field Bias in Women

Lateralization in emotional processing is a matter of ongoing debate. Various factors can influence lateralized emotional processing, including stimulus location, emotional valence, and gender. In the present study, we aim to elucidate how unattended emotional facial expressions shown at different locations in the visual field influence behavioral responses, eye movement, and neural responses in a sample of healthy women. Our female participants viewed fearful, happy and neutral faces presented at central and peripheral (left or right) locations while keeping their gaze locked on a central fixation crosshairs and indicating stimulus location via button presses. Throughout the experiment, we monitored fixation and gaze shifts by means of eye tracking. We analyzed eye movements, neural and behavioral responses from n = 18 participants with excellent tracking and task performance. Face stimuli presented in the left hemifield entailed the fastest reactions irrespective of face valence. Unwarranted gaze shifts away from central fixation were rare and mainly directed at peripherally presented stimuli. A distributed neural network comprising the right amygdala, left temporal pole, left middle temporal gyrus, right superior frontal gyrus, and right posterior putamen differentially responded to centrally presented fearful faces, and to peripherally presented neutral and happy faces, especially when they appeared in the left hemifield. Our findings point to a visual field bias on the behavioral and neural level in our female sample. Reaction times, eye movements and neural activations varied according to stimulus location. An interactive effect of face location with face valence was present at the neural level but did not translate to behavioral or eye movement responses.

Development of the Korean Facial Emotion Stimuli: Korea University Facial Expression Collection 2nd Edition

Background: Developing valid emotional facial stimuli for specific ethnicities creates ample opportunities to investigate both the nature of emotional facial information processing in general and clinical populations as well as the underlying mechanisms of facial emotion processing within and across cultures. Given that most entries in emotional facial stimuli databases were developed with western samples, and given that very few of the eastern emotional facial stimuli sets were based strictly on the Ekman’s Facial Action Coding System, developing valid emotional facial stimuli of eastern samples remains a high priority.

Aims: To develop and examine the psychometric properties of six basic emotional facial stimuli recruiting professional Korean actors and actresses based on the Ekman’s Facial Action Coding System for the Korea University Facial Expression Collection-Second Edition (KUFEC-II).

Materials And Methods: Stimulus selection was done in two phases. First, researchers evaluated the clarity and intensity of each stimulus developed based on the Facial Action Coding System. Second, researchers selected a total of 399 stimuli from a total of 57 actors and actresses, which were then rated on accuracy, intensity, valence, and arousal by 75 independent raters.

Conclusion: The hit rates between the targeted and rated expressions of the KUFEC-II were all above 80%, except for fear (50%) and disgust (63%). The KUFEC-II appears to be a valid emotional facial stimuli database, providing the largest set of emotional facial stimuli. The mean intensity score was 5.63 (out of 7), suggesting that the stimuli delivered the targeted emotions with great intensity. All positive expressions were rated as having a high positive valence, whereas all negative expressions were rated as having a high negative valence. The KUFEC II is expected to be widely used in various psychological studies on emotional facial expression. KUFEC-II stimuli can be obtained through contacting the corresponding authors.

Effects of Viewing Pleasant and Unpleasant Photographs on Facial EMG Asymmetry

40 subjects' facial electromyographic (EMG) activity at the corrugator and zygomatic muscle regions were recorded while they were viewing pleasant and unpleasant photographs. Analysis showed that the EMG activity at the left zygomatic muscle region generated the highest power, followed by the right zygomatic, left corrugator, and right corrugator muscle regions, while viewing pleasant photographs. The EMG activity at the left corrugator muscle region generated the highest power, followed by the right corrugator, left zygomatic, and right zygomatic muscle regions, while viewing unpleasant photographs. Further statistical analysis indicated that the EMG activities at the left corrugator region generated significantly higher power than those at the right corrugator region while viewing unpleasant photographs. It was concluded that the intensity of facial EMG activity on the left side of the face was stronger than the right side of the face during the process of emotional expression.

Lateralisation of emotions: evidence from pupil size measurement

The way our brain processes emotional stimuli has been studied intensively. One of the main issues still under debate is the laterality of valence processing. Herein, we employed the fact that pupil size increases under conditions of higher mental effort and during emotional processing, in order to contrast three proposed hypotheses in the field. We used different manual response mapping for emotional stimuli: Participants responded with their right hand for positive and with their left hand for negative facial expressions, or vice versa. The hands position was either regular (Experiment 1) or crossed (Experiment 2) in order to rule out a "spatial-valence association" alternate explanation. A third experiment was conducted by employing a passive viewing procedure of peripheral emotional stimuli. In the first two experiments, pupil size was larger when participants responded to positive stimuli with their left hand and to negative with their right hand, compared with the opposite mapping. Results of Experiment 3 strengthen the findings of Experiments 1 and 2. These findings provide significant psychophysiological evidence for the valence hypothesis: Processing positive stimuli involves the left hemisphere, while processing negative stimuli involves the right hemisphere. These results are discussed in relation to contemporary theories of emotion processing.

Which Cheek did the Resurrected Jesus Turn?

Secular portraits are likely to show more of the left than right side of the face (hemiface). Prior research has shown that emotions are more strongly expressed by the left hemiface. In addition, the valence theory of emotion proposes that the right hemisphere is dominant for mediating negative emotions, and the left hemisphere for positive emotions. Since religious art depicting a scene such as the Resurrection of Jesus is more likely to be associated with positive emotions, we postulated that there would be a significant smaller percentage number of artistic works of the Resurrection that reveal the left side of the face of Jesus than in those art works portraying the Crucifixion. Thus, we analyzed artistic portrayals of the Resurrection of Jesus and compared them to the artistic scenes of the Crucifixion. This analysis revealed that the left side of the face of Jesus is less commonly depicted in portraits of the Resurrection than the Crucifixion. In addition, both the right hemiface, and forward-facing faces were also more commonly portrayed in painting of the Resurrection than the Crucifixion. Whereas this right-left hemiface, Resurrection-Crucifixion dichotomy may be related to right-left hemispheric difference in the mediation of emotional valence other factors such as agency, action-intention, and biblical text may have influenced these differences.

Visuospatial and mathematical dysfunction in major depressive disorder and/or panic disorder: A study of parietal functioning

The parietal cortex is critical for several different cognitive functions, including visuospatial processing and mathematical abilities. There is strong evidence indicating parietal dysfunction in depression. However, it is less clear whether anxiety is associated with parietal dysfunction and whether comorbid depression and anxiety are associated with greater impairment. The present study compared participants with major depression (MDD), panic disorder (PD), comorbid MDD/PD and controls on neuropsychological measures of visuospatial processing, Judgement of Line Orientation (JLO), and mathematical abilities, Wide Range Achievement Test (WRAT) Arithmetic. Only comorbid MDD/PD was associated with decreased performance on JLO, whereas all psychopathological groups exhibited comparably decreased performance on WRAT Arithmetic. Furthermore, the results were not accounted for by other comorbid disorders, medication use or psychopathology severity. The present study suggests comorbid depression and anxious arousal are associated with impairment in visuospatial processing and provides novel evidence indicating mathematical deficits across depression and/or anxiety. Implications for understanding parietal dysfunction in internalising psychopathology are discussed.

Improvement of facial affect recognition in children and adolescents with attention-deficit/hyperactivity disorder under methylphenidate

INTRODUCTION AND HYPOTHESIS

Some authors draw a connection between the dopaminergic pathways and emotional perception. The present study is based on that association and addresses the question whether methylphenidate and the resulting amelioration of the disturbed dopamine metabolism lead to an improvement of the facial affect recognition abilities in children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

A computer test was conducted on 21 participants, aged 7-14 years and with a diagnosis of ADHD - some with comorbid oppositional defiant disorder - conducted the FEFA (Frankfurt Test and Training of Facial Affect), a computer test to examine their facial affect recognition abilities. It consists of two subtests, one with faces and one with eye pairs. All participants were tested in a double-blind cross-over study, once under placebo and once under methylphenidate.

RESULTS AND DISCUSSION

The collected data showed that methylphenidate leads to amelioration of facial affect recognition abilities, but not on a significant level. Reasons for missing significance may be the small sample size or the fact that there exists some overlapping in cerebral connections and metabolic pathways of the site of action of methylphenidate and the affected dopaminergic areas in ADHD. However, consistent with the endophenotype concept, certain gene locations of the dopaminergic metabolism as both an aetiological factor for ADHD and the deficient facial affect recognition abilities with these individuals were considered. Consulting current literature they were found to be not concordant. Therefore, we conclude that the lacking significance of the methylphenidate affect on facial affect recognition is based on this fact.

Affective communication deficits associated with cerebellar degeneration

The cerebellum has extensive connections with the frontal lobes. Cerebellar injury has been reported to induce frontal-executive cognitive dysfunction and blunting of affect. We examined a patient with idiopathic cerebellar degeneration with impaired family relationships attributed to an "emotional disconnection." Examination revealed ataxia, dysmetria, and adiadochokinesia more severe on the left and frontal-executive dysfunction; memory and cognitive functions were otherwise normal. Testing of emotional communication included assessments of emotional semantic knowledge, emotional prosody, and emotional facial expressions. Comprehension was normal but expression was severely impaired. Cerebellar dysfunction can cause a defect in facial and prosodic emotional communication.

Continuities in emotion lateralization in human and non-human primates

Where hemispheric lateralization was once considered an exclusively human trait, it is increasingly recognized that hemispheric asymmetries are evident throughout the animal kingdom. Emotion is a prime example of a lateralized function: given its vital role in promoting adaptive behavior and hence survival, a growing body of research in affective neuroscience is working to illuminate the cortical bases of emotion processing. Presuming that human and non-human primates evolved from a shared ancestor, one would anticipate evidence of organizational continuity in the neural substrate supporting emotion processing. This paper thus reviews research examining the patterns of lateralization for the expression and perception of facial emotion in non-human primates, aiming to determine whether the patterns of hemispheric asymmetry that characterize the human brain are similarly evident in other primate species. As such, this review seeks to enhance understanding of the evolution of hemispheric specialization for emotion, using emotion lateralization in non-human primates as a window through which to view emotion lateralization in humans.

Right frontal cortical lesions disrupt anger mimicry

The current study investigates the neural substrates of facial expression mimicry by assessing individuals with right and left lateralised frontal cortical lesions. Electromyography was used to measure spontaneous changes in electrical activity over the corrugator supercilii (brow) and zygomaticus major (cheek) muscle regions in response to happy and angry facial expressions. Individuals with right (n=4) and left (n=5) frontal cortical lesions and demographically matched controls (n=9) were compared. It was shown that while all three groups mimic happy facial expressions, only controls and individuals with left frontal lesions mimic angry expressions. These data are consistent with evidence for right frontal cortical specialisation for the processing of anger.

Are You Crying or Laughing? Emotion Recognition Deficits After Severe Traumatic Brain Injury

To date there has been little research concerning the neuropsychological mechanisms of emotion perception deficits following traumatic brain injury (TBI), although such deficits are well documented. This paper considers two major issues. First, are emotion-processing deficits found regardless of the media of presentation? In a recent study examining this issue, adults with severe TBI were found to have particular problems identifying emotions from conversational tone, as well as difficulties when presented with still photographs and audiovisual dynamic displays (videoed vignettes). They were relatively normal when asked to classify emotions on the basis of moving visual displays without sound. This may reflect the fact that the parietal cortices, important for processing movement, are relatively unscathed in TBI. The second issue concerns whether emotion recognition is facilitated by empathic emotional responses and whether these are diminished in people with TBI. Evidence is presented for a relation between subjective reports of diminished emotional experience and emotion recognition accuracy. Finally, preliminary data suggests that people with TBI may fail to have empathic reactions when asked to passively view emotional expressions.

Recognition of Natural Expressions of Emotion by CVA Patients with Damage to the Left or Right Hemisphere

The present study investigated the ability of cerebrovascular accident (CVA) patients to perceive emotions portrayed by realistic stimuli. Statistical analyses demonstrated that CVA patients with damage to either the right or left cerebral hemisphere performed, on average, as well as controls did in perceiving emotions. However, a case study of one patient suggested that there may be a subset of CVA patients with right parieto-occipital damage who have deficits in the perception of negative emotions. The performance of this participant also indicated that deficits in emotion perception are ameliorated to some extent when patients are provided with realistic, complex stimuli that include a range of auditory and visual cues.

Unconscious processing of emotions and the right hemisphere

This survey takes into account the unconscious aspects of emotions and the critical role played in them by the right hemisphere, considering different acceptations of the term 'unconscious'. In a preliminary step, the nature of emotions, their componential and hierarchical organization and the relationships between emotions and hemispheric specialization are shortly discussed, then different aspects of emotions are surveyed: first are reviewed studies dealing with the unconscious processing of emotional information, taking separately into account various lines of research. All these studies suggest that unconscious processing of emotional information is mainly subsumed by a right hemisphere subcortical route, through which emotional stimuli quickly reach the amygdala. We afterwards inquire if a right hemisphere dominance can also be observed in automatic emotional action schemata and if 'non-removed preverbal implicit memories' also have a preferential link with the right hemisphere. Finally, we try to evaluate if the right hemisphere may also play a critical role in dynamic unconscious phenomena, such as anosognosia/denial of hemiplegia in patients with unilateral brain lesions. In the last part of the review, the reasons that could subsume the right hemisphere dominance for unconscious emotions are shortly discussed.

The right-hemisphere and valence hypotheses: could they both be right (and sometimes left)?

The two halves of the brain are believed to play different roles in emotional processing, but the specific contribution of each hemisphere continues to be debated. The right-hemisphere hypothesis suggests that the right cerebrum is dominant for processing all emotions regardless of affective valence, whereas the valence specific hypothesis posits that the left hemisphere is specialized for processing positive affect while the right hemisphere is specialized for negative affect. Here, healthy participants viewed two split visual-field facial affect perception tasks during functional magnetic resonance imaging, one presenting chimeric happy faces (i.e. half happy/half neutral) and the other presenting identical sad chimera (i.e. half sad/half neutral), each masked immediately by a neutral face. Results suggest that the posterior right hemisphere is generically activated during non-conscious emotional face perception regardless of affective valence, although greater activation is produced by negative facial cues. The posterior left hemisphere was generally less activated by emotional faces, but also appeared to recruit bilateral anterior brain regions in a valence-specific manner. Findings suggest simultaneous operation of aspects of both hypotheses, suggesting that these two rival theories may not actually be in opposition, but may instead reflect different facets of a complex distributed emotion processing system.

Cerebral localization of functions and the neurology of language: fact versus fiction or is it something else?

Over the last 15 years there has been a burgeoning number of publications using functional brain imaging (>40,000 articles based on an ISI/Web of Science search) to localize behavioral and cognitive processes to specific areas in the human brain that are often not confirmed by traditional, lesion-based studies. Thus, there is a need to reassess what cerebral localization of functions is and is not. Otherwise, there is no rational way to interpret the escalating claims of localization in the functional imaging literature that is taking on the appearance of neurophysiologic "phrenology". This article will present arguments to suggest that functional localization in the brain is a robust but very dynamic, four-dimensional process. It is a learned phenomenon driven over time by large-scale, spatially distributed, neural networks seeking to efficiently maximize the processing, storage, and manipulation of information for cognitive and behavioral operations. Because of historical considerations and space limitations, the main focus will be on localization of language-related functions whose theoretical neurological basis can be generalized for any complex cognitive-behavioral function.

Neuropsychological and interpersonal antecedents of youth depression

This research examined neuropsychological and interpersonal factors that jointly confer vulnerability to youth depression. We proposed that (1) a reduced posterior right hemisphere bias during the processing of facial expressions contributes to subsequent depressive symptoms in youth, and (2) maladaptive responses to interpersonal stress account for this association. Drawing from theory and research indicating sex differences in rates of hemispheric development, we also investigated sex differences in the associations among a reduced posterior right hemisphere bias, maladaptive responses to interpersonal stress, and depressive symptoms. Hypotheses were examined in a longitudinal study of 95 4^th - 8^th graders (M age = 12.33, SD = 1.10). Results supported the notion that a reduced posterior right hemisphere bias confers vulnerability to depressive symptoms over time in a sex-specific fashion, and implicate maladaptive stress responses as an explanatory mechanism.

Damage to association fiber tracts impairs recognition of the facial expression of emotion

An array of cortical and subcortical structures have been implicated in the recognition of emotion from facial expressions. It remains unknown how these regions communicate as parts of a system to achieve recognition, but white matter tracts are likely critical to this process. We hypothesized that (1) damage to white matter tracts would be associated with recognition impairment and (2) the degree of disconnection of association fiber tracts [inferior longitudinal fasciculus (ILF) and/or inferior fronto-occipital fasciculus (IFOF)] connecting the visual cortex with emotion-related regions would negatively correlate with recognition performance. One hundred three patients with focal, stable brain lesions mapped onto a reference brain were tested on their recognition of six basic emotional facial expressions. Association fiber tracts from a probabilistic atlas were coregistered to the reference brain. Parameters estimating disconnection were entered in a general linear model to predict emotion recognition impairments, accounting for lesion size and cortical damage. Damage associated with the right IFOF significantly predicted an overall facial emotion recognition impairment and specific impairments for sadness, anger, and fear. One subject had a pure white matter lesion in the location of the right IFOF and ILF. He presented specific, unequivocal emotion recognition impairments. Additional analysis suggested that impairment in fear recognition can result from damage to the IFOF and not the amygdala. Our findings demonstrate the key role of white matter association tracts in the recognition of the facial expression of emotion and identify specific tracts that may be most critical.

Temporal pole activity during perception of sad faces, but not happy faces, correlates with neuroticism trait

It is known that the temporal cortex is involved in perception of emotional facial expressions, and the involvement is relatively independent of the emotional valence of those expressions. The present study revealed a valence-dependent aspect of the temporal cortex through individual differences analyses involving the neuroticism trait, one of the representative affective personality traits. Functional MRI was administered while subjects classified expressions of faces, and neuroticism scores were obtained from individual subjects. Significant brain activity was observed in the temporal pole (TP) during perception of both happy and sad expressions relative to neutral expressions. Correlational analyses revealed that TP activity during perception of sad expressions, but not happy expressions, correlated with the neuroticism scores. These results demonstrate differential roles for the temporal cortex in perception of happy and sad faces, and suggest that TP recruitment during understanding of negative emotions is dependent on the personality of the individuals.

Perception and recall of faces and facial expressions following temporal lobectomy

The perception of and memory for faces, with or without emotional content, were studied in 43 patients with temporal lobe epilepsy who had undergone unilateral resection of the hippocampus and the amygdala and in 43 healthy participants for comparison. Each participant performed four tasks from the Florida Affect Battery (Facial Discrimination, Affect Discrimination, Affect Naming, Affect Selection) and two memory tasks (in one case of a face and in the other of a facial expression). Findings indicated that, although patients with unilateral temporal lobectomy (right or left) showed no difficulty in discriminating faces, they were not as good at remembering faces. Also, patients who had had a left temporal lobectomy showed impairment in discriminating facial expressions, in the memory of a facial expression and/or in naming facial expressions.

Emotionally arousing stimuli compete for attention with left hemispace

Rapid interaction of the emotional and attentional networks is critical for adaptive behavior. Here, we examined the effects of emotional stimulation on hemifield attention allocation using event-related potential and behavioral measures. Participants performed a visual-discrimination task on nonemotional targets presented randomly in the left or right hemifield. A brief task-irrelevant emotional (pleasant or unpleasant; 150-ms duration) or neutral picture was presented centrally 350 ms before the next target (150-ms duration). Unpleasant stimuli interfered with the left visual field attention capacity, slowing behavioral responses to attended left field stimuli. In keeping with the behavioral data, event-related potential responses to nonemotional attended left field stimuli were reduced over the right parietal regions when preceded by an unpleasant event. The results provide electrophysiological and behavioral evidence that unpleasant, emotionally arousing stimuli interfere with the right hemisphere-dependent attention capacity.