Impaired recognition of disgust in Huntington's disease gene carriers

Similarities and differences in the induction and regulation of the negative emotions fear and disgust: A functional near infrared spectroscopy study

Affective processing, including induction and regulation of emotion, activates neural networks, induces physiological responses, and generates subjective experience. Dysregulation of these processes can lead to maladaptive behavior and even psychiatric morbidity. Multimodal studies of emotion thus not only help elucidate the nature of emotion, but also contribute to important clinical insights. In the present study, we compared the induction (EI) and effortful regulation (ER) with reappraisal of fear and disgust in healthy subjects using functional near infrared spectroscopy (fNIRS) in conjunction with electrodermal activity (EDA). During EI, there was significant activation in medial prefrontal cortex (PFC) for fear and more widespread activation for disgust, with right lateral PFC significantly more active during disgust compared to fear. ER was equally effective for fear and disgust reducing subjective emotion rating by roughly 45%. Compared to baseline, there was no increased PFC activity for fear during ER, while for disgust lateral PFC was significantly more active. Significant differences between the two negative emotions were also observed in sympathetic nerve activity as reflected in EDA during EI, but not during ER. Lastly, compared to men, women had higher emotion rating for both fear and disgust without corresponding differences in EDA. In conclusion, in the present study we show that emotion induction was associated with differential activation in both PFC and sympathetic nerve activity for fear and disgust. These differences were however less prominent during emotion regulation. We discuss the potential interpretation of our results and their implications regarding our understanding of negative emotion processing.

Cognitive Dysfunction in Repeat Expansion Diseases: A Review

With the development of the sequencing technique, more than 40 repeat expansion diseases (REDs) have been identified during the past two decades. Moreover, the clinical features of these diseases show some commonality, and the nervous system, especially the cognitive function was affected in part by these diseases. However, the specific cognitive domains impaired in different diseases were inconsistent. Here, we survey literature on the cognitive consequences of the following disorders presenting cognitive dysfunction and summarizing the pathogenic genes, epidemiology, and different domains affected by these diseases. We found that the cognitive domains affected in neuronal intranuclear inclusion disease (NIID) were widespread including the executive function, memory, information processing speed, attention, visuospatial function, and language. Patients with C9ORF72-frontotemporal dementia (FTD) showed impairment in executive function, memory, language, and visuospatial function. While in Huntington's disease (HD), the executive function, memory, and information processing speed were affected, in the fragile X-associated tremor/ataxia syndrome (FXTAS), executive function, memory, information processing speed, and attention were impaired. Moreover, the spinocerebellar ataxias showed broad damage in almost all the cognitive domains except for the relatively intact language ability. Some other diseases with relatively rare clinical data also indicated cognitive dysfunction, such as myotonic dystrophy type 1 (DM1), progressive myoclonus epilepsy (PME), Friedreich ataxia (FRDA), Huntington disease like-2 (HDL2), and cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS). We drew a cognitive function landscape of the related REDs that might provide an aspect for differential diagnosis through cognitive domains and effective non-specific interventions for these diseases.

Profiling Social Cognition in Premanifest Huntington's Disease

OBJECTIVE

Discrepancies exist in reports of social cognition deficits in individuals with premanifest Huntington's disease (HD); however, the reason for this variability has not been investigated. The aims of this study were to (1) evaluate group- and individual-level social cognitive performance and (2) examine intra-individual variability (dispersion) across social cognitive domains in individuals with premanifest HD.

METHOD

Theory of mind (ToM), social perception, empathy, and social connectedness were evaluated in 35 individuals with premanifest HD and 29 healthy controls. Cut-off values beneath the median and 1.5 × the interquartile range below the 25th percentile (P25 - 1.5 × IQR) of healthy controls for each variable were established for a profiling method. Dispersion between social cognitive domains was also calculated.

RESULTS

Compared to healthy controls, individuals with premanifest HD performed worse on all social cognitive domains except empathy. Application of the profiling method revealed a large proportion of people with premanifest HD fell below healthy control median values across ToM (>80%), social perception (>57%), empathy (>54%), and social behaviour (>40%), with a percentage of these individuals displaying more pronounced impairments in empathy (20%) and ToM (22%). Social cognition dispersion did not differ between groups. No significant correlations were found between social cognitive domains and mood, sleep, and neurocognitive outcomes.

CONCLUSIONS

Significant group-level social cognition deficits were observed in the premanifest HD cohort. However, our profiling method showed that only a small percentage of these individuals experienced marked difficulties in social cognition, indicating the importance of individual-level assessments, particularly regarding future personalised treatments.

Impaired Perception of Unintentional Transgression of Social Norms after Prefrontal Cortex Damage: Relationship to Decision Making, Emotion Recognition, and Executive Functions

OBJECTIVE

Patients with prefrontal cortex damage often transgress social rules and show lower accuracy in identifying and explaining inappropriate social behavior. The objective of this study was to examine the relationship between the ability to perceive other unintentional transgressions of social norms and both decision making and emotion recognition as these abilities are critical for appropriate social behavior.

METHOD

We examined a group of patients with focal prefrontal cortex damage (N = 28) and a group of matched control participants (N = 28) for their abilities to detect unintentional transgression of social norms using the "Faux-Pas" task of theory of mind, to make advantageous decisions on the Iowa gambling task, and to recognize basic emotions on the Ekman facial affect test.

RESULTS

The group of patients with frontal lobe damage was impaired in all of these tasks compared with control participants. Moreover, all the "Faux-Pas", Iowa gambling, and emotion recognition tasks were significantly associated and predicted by executive measures of inhibition, flexibility, or planning. However, only measures from the Iowa gambling task were associated and predicted performance on the "Faux-Pas" task. These tasks were not associated with performance in recognition of basic emotions. These findings suggest that theory of mind, executive functions, and decision-making abilities act in an interdependent way for appropriate social behavior. However, theory of mind and emotion recognition seem to have distinct but additive effects upon social behavior. Results from VLSM analysis also corroborate these data by showing a partially overlapped prefrontal circuitry underlying these cognitive domains.

Impaired social perception from eyes and face visual cues: evidence from prefrontal cortex damage

Despite the key role that decoding of social-perceptual cues from faces plays in interpersonal communication, it is only recently that the potential of prefrontal cortex damage to disrupt this ability has been recognized. In fact, few studies to date had assessed whether the ability to identify the state of mind of others from the whole or part of the face is disrupted after prefrontal cortex damage and whether these two abilities are associated and share overlapped neural systems. In the present study, 30 patients with focal prefrontal lesions and 30 matched control subjects were assessed on their ability to recognize six basic emotions from facial expressions of the whole face and to identify states of mind of others from photographs of only the eyes using the "Reading the Mind in the Eyes Task". Results showed that frontal patients were significantly impaired compared with control subjects on both tasks. Moreover, regression analyses showed that these two abilities are associated and reciprocally predictive of one another. Finally, using voxel-based lesion analysis; we identified a partially common bilaterally distributed prefrontal network in the decoding of both emotional cues from both the whole face and eyes centered within the dorsomedial and ventral regions with extension to the lateral frontal pole.

Problems with Social Cognition and Decision-Making in Huntington's Disease: Why Is it Important?

Huntington’s disease starts slowly and progresses over a 15–20 year period. Motor changes begin subtly, often going unnoticed by patients although they are typically visible to those close to them. At this point, it is the early non-motor problems of HD that arguably cause the most functional impairment. Approximately 65% of gene carriers will experience a reduction in their occupational level, and just under half will feel unable to manage their finances independently before a clinical diagnosis is made. Understanding what drives this impairment in activities of daily living is the key to helping people with HD to live more independently for longer, especially in early disease. Early cognitive decline is likely to play a contributory factor although few studies have looked directly at this relationship. Recently, it has been shown that along with the well documented dysexecutive syndrome seen in HD, changes in social cognition and decision-making are more common than previously thought. Furthermore, some of the early neuropathological and neurochemical changes seen in HD disrupt networks known to be involved in social functioning. In this review, we explore how HD changes the way individuals interact in a social world. Specifically, we summarise the literature on both classical and social decision-making (value-based decision-making in a social context) along with studies of theory of mind, empathy, alexithymia, and emotion recognition in HD. The literature specific to HD is discussed and supported by evidence from similar neurodegenerative disorders and healthy individuals to propose future directions and potential therapeutic avenues to be explored.

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.

Diminished facial EMG responses to disgusting scenes and happy and fearful faces in Huntington's disease

Huntington's disease (HD) is a neurodegenerative disorder associated with impaired facial emotion recognition and altered subjective experience of emotion. These impairments likely result from the effects of the disease on underlying neurobiological mechanisms. Studies using self-report to examine emotional experiences have been ambiguous regarding whether experiences are diminished or exaggerated, possibly due to cognitive impairment and lack of insight in HD. To infer affective states more objectively and overcome the limitations of self-report, we used facial EMG to measure muscle responses to emotionally-evocative scenes. Further, we examined muscle responses to emotionally-expressive faces, because facial mimicry is thought to facilitate emotion recognition and social affiliation. Twenty-three HD participants (late pre-manifest and early symptomatic) were compared to twenty-five healthy controls in a scene condition and a face condition. EMG activity was measured from facial muscles associated with expressing particular emotions: 1) corrugator supercilii for anger, 2) frontalis for fear, 3) levator labii for disgust, and 4) both zygomaticus major and orbicularis oculi for happiness. Compared to controls, HD participants showed diminished responses to disgusting scenes, and to happy and fearful faces. Our findings provide evidence for a loss of disgust experience in HD. Further, consistent with the alleged affiliative function of facial mimicry, diminished mimicry responses may be relevant to social-emotional changes in HD. Our findings help understand the neural mechanisms underlying emotion processing impairments in HD.

Oxytocin selectively modulates brain processing of disgust in Huntington's disease gene carriers

People with Huntington's disease (HD) exhibit altered processing of emotional information, especially disgust and other negative emotions. These impairments are likely due to the effects of the disease on underlying brain networks. We examined whether oxytocin, when given intranasally, would normalise aberrant brain reactivity to emotional faces in participants with the gene-expansion for HD. In a double-blind placebo-controlled cross-over design, we measured brain activity, using functional magnetic resonance imaging, whilst nine medication-free HD carriers, and ten control participants viewed emotional (disgust, fear, angry, sad, surprise, happy) and neutral faces, following acute intranasal oxytocin (24IU) and placebo. Subjective mood changes were assessed before and after the neuroimaging on each visit. Permutation-based non-parametric statistical testing for the whole brain, showed significant group×drug interactions (p's<0.05, TFCE corrected) in areas of the left frontal pole, superior frontal, and middle frontal gyri cortically, and left putamen and thalamus sub-cortically. Parameter estimates extracted from the middle frontal gyrus and putamen showed that, under placebo, the HD group had lower brain activity to disgust stimuli, compared with controls. After intranasal oxytocin, the pattern of activation to disgust stimuli was normalised in the HD group to similar levels as controls; eight of the nine HD carriers showed increased response in the middle frontal gyrus, and seven of the nine HD carriers showed increased response in the putamen. The observed effects of oxytocin occurred in the absence of changes in subjective mood or state anxiety. These findings provide early evidence for a physiological role of oxytocin in the neuropathology of HD. Our findings are the first reported oxytocin effects in a neurodegenerative disease. Further research should examine the therapeutic benefits of oxytocin in alleviating emotional and social cognition deficits in HD and related disorders.

Through your eyes or mine? The neural correlates of mental state recognition in Huntington's disease

Huntington's disease (HD) can impair social cognition. This study investigated whether patients with HD exhibit neural differences to healthy controls when they are considering mental and physical states relating to the static expressions of human eyes. Thirty-two patients with HD and 28 age-matched controls were scanned with fMRI during two versions of the Reading the Mind in the Eyes Task: The standard version requiring mental state judgments, and a comparison version requiring judgments about age. HD was associated with behavioral deficits on only the mental state eyes task. Contrasting the two versions of the eyes task (mental state > age judgment) revealed hypoactivation within left middle frontal gyrus and supramarginal gyrus in HD. Subgroup analyses comparing premanifest HD patients to age-matched controls revealed reduced activity in right supramarginal gyrus and increased activity in anterior cingulate during mental state recognition in these patients, while manifest HD was associated with hypoactivity in left insula and left supramarginal gyrus. When controlling for the effects of healthy aging, manifest patients exhibited declining activation within areas including right temporal pole. Our findings provide compelling evidence for a selective impairment of internal emotional status when patients with HD appraise facial features in order to make social judgements. Differential activity in temporal and anterior cingulate cortices may suggest that poor emotion regulation and emotional egocentricity underlie impaired mental state recognition in premanifest patients, while more extensive mental state recognition impairments in manifest disease reflect dysfunction in neural substrates underlying executive functions, and the experience and interpretation of emotion.

Facial Expressions in Context: Electrophysiological Correlates of the Emotional Congruency of Facial Expressions and Background Scenes

Facial expressions can display personal emotions and indicate an individual’s intentions within a social situation. They are extremely important to the social interaction of individuals. Background scenes in which faces are perceived provide important contextual information for facial expression processing. The purpose of this study was to explore the time course of emotional congruency effects in processing faces and scenes simultaneously by recording event-related potentials (ERPs). The behavioral results found that the categorization of facial expression was faster and more accurate when the face was emotionally congruent than incongruent with the emotion displayed by the scene. In ERPs the late positive potential (LPP) amplitudes were modulated by the emotional congruency between faces and scenes. Specifically, happy faces elicited larger LPP amplitudes within positive than within negative scenes and fearful faces within negative scenes elicited larger LPP amplitudes than within positive scenes. The results did not find the scene effects on the P1 and N170 components. These findings indicate that emotional congruency effects could occur in late stages of facial expression processing, reflecting motivated attention allocation.

Core, social and moral disgust are bounded: A review on behavioral and neural bases of repugnance in clinical disorders

Disgust is a multifaceted experience that might affect several aspects of life. Here, we reviewed research on neurological and psychiatric disorders that are characterized by abnormal disgust processing to test the hypothesis of a shared neurocognitive architecture in the representation of three disgust domains: i) personal experience of 'core disgust'; ii) social disgust, i.e., sensitivity to others' expressions of disgust; iii) moral disgust, i.e., sensitivity to ethical violations. Our review provides some support to the shared neurocognitive hypothesis and suggests that the insula might be the "hub" structure linking the three domains of disgust sensitivity, while other brain regions may subserve specific facets of the multidimensional experience. Our review also suggests a role of serotonin core and moral disgust, supporting "neo-sentimentalist" theories of morality, which posit a causal role of affect in moral judgment.

The neuropsychology of first impressions: Evidence from Huntington's disease

Impairments of emotion recognition have been widely documented in Huntington's disease (HD), but little is known concerning how these relate to other aspects of social cognition, including first impressions of traits such as trustworthiness and dominance. Here, we introduce a novel and sensitive method to investigate the ability to evaluate trustworthiness and dominance from facial appearance, with control tasks measuring ability to perceive differences between comparable stimuli. We used this new method together with standard tests of face perception to investigate social cognition in HD. We found that a subgroup of people with HD was impaired at perceiving trustworthiness and dominance, and that perceiving trustworthiness and dominance were correlated with impaired facial expression recognition. In addition, we used diffusion tensor imaging (DTI) to provisionally identify candidate brain regions associated with social cognition by contrasting regional functional anisotropy (FA) measures between subgroups of HD participants showing normal or impaired perception of trustworthiness and dominance, and by correlating these regional brain abnormalities with behavioural performance on tests of emotion recognition. In this way we show for the first time alterations in perception of trustworthiness and dominance in people with HD and link these to regions which may map the boundaries of the social brain. The pattern of breakdown seen in this neurodegenerative disease can thus be used to explore potential inter-relationships between different components of social cognition.

The Neural Bases of Disgust for Cheese: An fMRI Study

The study of food aversion in humans by the induction of illness is ethically unthinkable, and it is difficult to propose a type of food that is disgusting for everybody. However, although cheese is considered edible by most people, it can also be perceived as particularly disgusting to some individuals. As such, the perception of cheese constitutes a good model to study the cerebral processes of food disgust and aversion. In this study, we show that a higher percentage of people are disgusted by cheese than by other types of food. Functional magnetic resonance imaging then reveals that the internal and external globus pallidus and the substantia nigra belonging to the basal ganglia are more activated in participants who dislike or diswant to eat cheese (Anti) than in other participants who like to eat cheese, as revealed following stimulation with cheese odors and pictures. We suggest that the aforementioned basal ganglia structures commonly involved in reward are also involved in the aversive motivated behaviors. Our results further show that the ventral pallidum, a core structure of the reward circuit, is deactivated in Anti subjects stimulated by cheese in the wanting task, highlighting the suppression of motivation-related activation in subjects disgusted by cheese.

Insular atrophy and diminished disgust reactivity

Disgust is an emotion that helps us deal with potential contamination (Rozin & Fallon, 1987). It produces a distinctive facial expression (e.g., wrinkled nose) and a physiological response that is accompanied by strong visceral sensations (e.g., nausea). Given the important role that the anterior insula plays in processing and integrating visceral information (Craig, 2009), it is likely to be centrally involved in disgust. Despite this, few studies have examined the link between insular degeneration and the experience, physiology, and expression of disgust. We studied a group that was heterogeneous in terms of insular damage: 84 patients with neurodegenerative diseases (i.e., frontotemporal dementia, corticobasal syndrome, progressive supranuclear palsy, Alzheimer's disease) and 29 controls. Subjects viewed films that elicit high levels of disgust and sadness. Emotional reactivity was assessed using self-report, peripheral physiology, and facial behavior. Regional brain volumes (insula, putamen, pallidum, caudate, and amygdala) were determined from structural MRIs using the FreeSurfer method. Results indicated that smaller insular volumes were associated with reduced disgust responding in self-report and physiological reactivity, but not in facial behavior. In terms of the specificity of these findings, insular volume did not predict sadness reactivity, and disgust reactivity was not predicted by putamen, pallidum, and caudate volumes (lower self-reported disgust was associated with smaller amygdala volume). These findings underscore the central role of the insula in the experience and physiology of disgust. (PsycINFO Database Record

Social cognition in Huntington's disease: A meta-analysis

Neurocognitive impairment in Huntington's disease (HD) frequently includes deficits in emotion recognition, and recent studies have also provided evidence for deficits in theory of mind (ToM). There have been conflicting reports regarding the extent of emotion recognition and ToM deficits before the onset of motor symptoms in HD. In this meta-analysis, ToM and emotion recognition performances of 2226HD or pre-manifest HD and 998 healthy controls were included in the meta-analysis. Meta-regression analyses were conducted to investigate the relationship between social cognition deficits and demographic, cognitive and clinical features in HD. HD patients were significantly less accurate than controls in ToM and across all emotions in response to both facial and vocal stimuli. ToM (d=1.72) and recognition of negative emotions (d=1.20-1.33), especially anger, disgust and fear (d=1.26-1.52) were severely impaired. Pre-manifest HD was also associated with impairment in social cognition. The severity of emotion recognition impairment was significantly associated with disease burden, proximity of onset of motor symptoms and cognitive impairment. Social cognition impairments are potential biomarkers of disease onset and progression in HD.

Large-scale brain network abnormalities in Huntington's disease revealed by structural covariance

Huntington's disease (HD) is a progressive neurodegenerative disorder that can be diagnosed with certainty decades before symptom onset. Studies using structural MRI have identified grey matter (GM) loss predominantly in the striatum, but also involving various cortical areas. So far, voxel-based morphometric studies have examined each brain region in isolation and are thus unable to assess the changes in the interrelation of brain regions. Here, we examined the structural covariance in GM volumes in pre-specified motor, working memory, cognitive flexibility, and social-affective networks in 99 patients with manifest HD (mHD), 106 presymptomatic gene mutation carriers (pre-HD), and 108 healthy controls (HC). After correction for global differences in brain volume, we found that increased GM volume in one region was associated with increased GM volume in another. When statistically comparing the groups, no differences between HC and pre-HD were observed, but increased positive correlations were evident for mHD, relative to pre-HD and HC. These findings could be explained by a HD-related neuronal loss heterogeneously affecting the examined network at the pre-HD stage, which starts to dominate structural covariance globally at the manifest stage. Follow-up analyses identified structural connections between frontoparietal motor regions to be linearly modified by disease burden score (DBS). Moderator effects of disease load burden became significant at a DBS level typically associated with the onset of unequivocal HD motor signs. Together with existing findings from functional connectivity analyses, our data indicates a critical role of these frontoparietal regions for the onset of HD motor signs.

Impaired Recognition and Regulation of Disgust Is Associated with Distinct but Partially Overlapping Patterns of Decreased Gray Matter Volume in the Ventroanterior Insula

BACKGROUND

The ventroanterior insula is implicated in the experience, expression, and recognition of disgust; however, whether this brain region is required for recognizing disgust or regulating disgusting behaviors remains unknown.

METHODS

We examined the brain correlates of the presence of disgusting behavior and impaired recognition of disgust using voxel-based morphometry in a sample of 305 patients with heterogeneous patterns of neurodegeneration. Permutation-based analyses were used to determine regions of decreased gray matter volume at a significance level p <= .05 corrected for family-wise error across the whole brain and within the insula.

RESULTS

Patients with behavioral variant frontotemporal dementia and semantic variant primary progressive aphasia were most likely to exhibit disgusting behaviors and were, on average, the most impaired at recognizing disgust in others. Imaging analysis revealed that patients who exhibited disgusting behaviors had significantly less gray matter volume bilaterally in the ventral anterior insula. A region of interest analysis restricted to behavioral variant frontotemporal dementia and semantic variant primary progressive aphasia patients alone confirmed this result. Moreover, impaired recognition of disgust was associated with decreased gray matter volume in the bilateral ventroanterior and ventral middle regions of the insula. There was an area of overlap in the bilateral anterior insula where decreased gray matter volume was associated with both the presence of disgusting behavior and impairments in recognizing disgust.

CONCLUSIONS

These findings suggest that regulating disgusting behaviors and recognizing disgust in others involve two partially overlapping neural systems within the insula. Moreover, the ventral anterior insula is required for both processes.

Emotional dysfunctions in neurodegenerative diseases

Neurodegenerative diseases are characterized primarily by motor signs but are also accompanied by emotional disturbances. Because of the limited knowledge about these dysfunctions, this Review provides an overview of emotional competencies in Huntington's disease (HD), Parkinson's disease (PD), and multiple sclerosis (MS), with a focus on emotion recognition, emotion regulation, and depression. Most studies indicate facial emotion recognition deficits in HD and PD, whereas data for MS are inconsistent. On a neural level, dysfunctions of amygdala and striatum, among others, have been linked to these impairments. These dysfunctions also tap brain regions that are part of the emotion regulation network, suggesting problems in this competency, too. Research points to dysfunctional emotion regulation in MS, whereas findings for PD and HD are missing. The high prevalence of depression in all three disorders emphasizes the need for effective therapies. Research on emotional disturbances might improve treatment, thereby increasing patients' and caregivers' well-being.

The role of the amygdala during emotional processing in Huntington's disease: from pre-manifest to late stage disease

BACKGROUND

Deficits in emotional processing can be detected in the pre-manifest stage of Huntington's disease and negative emotion recognition has been identified as a predictor of clinical diagnosis. The underlying neuropathological correlates of such deficits are typically established using correlative structural MRI studies. This approach does not take into consideration the impact of disruption to the complex interactions between multiple brain circuits on emotional processing. Therefore, exploration of the neural substrates of emotional processing in pre-manifest HD using fMRI connectivity analysis may be a useful way of evaluating the way brain regions interrelate in the period prior to diagnosis.

METHODS

We investigated the impact of predicted time to disease onset on brain activation when participants were exposed to pictures of faces with angry and neutral expressions, in 20 pre-manifest HD gene carriers and 23 healthy controls. On the basis of the results of this initial study went on to look at amygdala dependent cognitive performance in 79 Huntington's disease patients from a cross-section of disease stages (pre-manifest to late disease) and 26 healthy controls, using a validated theory of mind task: "the Reading the Mind in the Eyes Test" which has been previously been shown to be amygdala dependent.

RESULTS

Psychophysiological interaction analysis identified reduced connectivity between the left amygdala and right fusiform facial area in pre-manifest HD gene carriers compared to controls when viewing angry compared to neutral faces. Change in PPI connectivity scores correlated with predicted time to disease onset (r=0.45, p<0.05). Furthermore, performance on the "Reading the Mind in the Eyes Test" correlated negatively with proximity to disease onset and became progressively worse with each stage of disease.

CONCLUSION

Abnormalities in the neural networks underlying social cognition and emotional processing can be detected prior to clinical diagnosis in Huntington's disease. Connectivity between the amygdala and other brain regions is impacted by the disease process in pre-manifest HD and may therefore be a useful way of identifying participants who are approaching a clinical diagnosis. Furthermore, the "Reading the Mind in the Eyes Test" is a surrogate measure of amygdala function that is clinically useful across the entire cross-section of disease stages in HD.

Basal ganglia-cortical structural connectivity in Huntington's disease

Huntington's disease is an incurable neurodegenerative disease caused by inheritance of an expanded cytosine-adenine-guanine (CAG) trinucleotide repeat within the Huntingtin gene. Extensive volume loss and altered diffusion metrics in the basal ganglia, cortex and white matter are seen when patients with Huntington's disease (HD) undergo structural imaging, suggesting that changes in basal ganglia-cortical structural connectivity occur. The aims of this study were to characterise altered patterns of basal ganglia-cortical structural connectivity with high anatomical precision in premanifest and early manifest HD, and to identify associations between structural connectivity and genetic or clinical markers of HD. 3-Tesla diffusion tensor magnetic resonance images were acquired from 14 early manifest HD subjects, 17 premanifest HD subjects and 18 controls. Voxel-based analyses of probabilistic tractography were used to quantify basal ganglia-cortical structural connections. Canonical variate analysis was used to demonstrate disease-associated patterns of altered connectivity and to test for associations between connectivity and genetic and clinical markers of HD; this is the first study in which such analyses have been used. Widespread changes were seen in basal ganglia-cortical structural connectivity in early manifest HD subjects; this has relevance for development of therapies targeting the striatum. Premanifest HD subjects had a pattern of connectivity more similar to that of controls, suggesting progressive change in connections over time. Associations between structural connectivity patterns and motor and cognitive markers of disease severity were present in early manifest subjects. Our data suggest the clinical phenotype in manifest HD may be at least partly a result of altered connectivity.

Recognition of facial emotions and identity in patients with mesial temporal lobe and idiopathic generalized epilepsy: an eye-tracking study

PURPOSE

To describe visual scanning pattern for facial identity recognition (FIR) and emotion recognition (FER) in patients with idiopathic generalized (IGE) and mesial temporal lobe epilepsy (MTLE). Secondary endpoint was to correlate the results with cognitive function.

METHODS

Benton Facial Recognition Test (BFRT) and Ekman&Friesen series were performed for FIR and FER respectively in 23 controls, 20 IGE and 19 MTLE patients. Eye movements were recorded by a Hi-Speed eye-tracker system. Neuropsychological tools explored cognitive function.

RESULTS

Correct FIR rate was 78% in controls, 70.7% in IGE and 67.4% (p=0.009) in MTLE patients. FER hits reached 82.7% in controls, 74.3% in IGE (p=0.006) and 73.4% in MTLE (p=0.002) groups. IGE patients failed in disgust (p=0.005) and MTLE ones in fear (p=0.009) and disgust (p=0.03). FER correlated with neuropsychological scores, particularly verbal fluency (r=0.542, p<0.001). Eye-tracking revealed that controls scanned faces more diffusely than IGE and MTLE patients for FIR, who tended to top facial areas. A longer scanning of the top facial area was found in the three groups for FER. Gap between top and bottom facial region fixation time decreased in MTLE patients, with more but shorter fixations in bottom facial region. However, none of these findings were statistically significant.

CONCLUSION

FIR was impaired in MTLE patients, and FER in both IGE and MTLE, particularly for fear and disgust. Although not statistically significant, those with impaired FER tended to perform more diffuse eye-tracking over the faces and have cognitive dysfunction.

A possible mechanism for PTSD symptoms in patients with traumatic brain injury: central autonomic network disruption

Patients with traumatic brain injuries (TBI) often develop post traumatic stress disorder (PTSD). This syndrome, defined and diagnosed by psychological and behavioral features, is associated with symptoms such as anxiety and anger with an increase of arousal and vigilance, as well as flashbacks and nightmares. Many of these features and symptoms observed in PTSD may be in part the result of altered autonomic nervous system (ANS) activity in response to psychological and physical challenges. Brain imaging has documented that TBI often induces white matter damage to pathways associated with the anterior limb of the internal capsule and uncinate fasciculus. Since these white matter structures link neocortical networks with subcortical and limbic structures that regulate autonomic control centers, injury to these pathways may induce a loss of inhibitory control of the ANS. In this review, the autonomic features associated with PTSD are discussed in the context of traumatic brain injury. We posit that TBI induced damage to networks that regulate the ANS increase vulnerability to PTSD. The means by which the vulnerability can be measured and tested are also discussed.

Facial Affect Recognition in Myasthenia Gravis

The assessment of facial expression is an important aspect of a clinical neurological examination, both as an indicator of a mood disorder and as a sign of neurological damage. To date, although studies have been conducted on certain psychosocial aspects of myasthenia, such as quality of life and anxiety, and on neuropsychological aspects such as memory, no studies have directly assessed facial emotion recognition accuracy. The aim of this study was to assess the facial emotion recognition accuracy (fear, surprise, sadness, happiness, anger, and disgust), empathy, and reaction time of patients with myasthenia. Thirty-five patients with myasthenia and 36 healthy controls were tested for their ability to differentiate emotional facial expressions. Participants were matched with respect to age, gender, and education level. Their ability to differentiate emotional facial expressions was evaluated using the computer-based program Feel Test. The data showed that myasthenic patients scored significantly lower (p < 0.05) than healthy controls in the total Feel score, fear, surprise, and higher reaction time. The findings suggest that the ability to recognize facial affect may be reduced in individuals with myasthenia.

Emotion recognition in the dementias: brain correlates and patient implications

SUMMARY Changes in behavior, personality and the ability to interact in social situations have been reported to varying extents across dementia syndromes. Deficits in the ability to recognize emotion in others probably contribute to these socioemotional changes. This article reviews the patterns of emotion recognition impairments and their underlying brain correlates in four dementia syndromes: Alzheimer’s disease; frontotemporal dementia; Huntington’s disease; and progressive supranuclear palsy. Despite emotion recognition deficits being observed in all these patient groups, a limited understanding exists on how these deficits translate into everyday behavior. The adoption of ecologically valid tasks is likely to improve our understanding of these deficits in everyday settings, and will help to provide guidance for management strategies for patients and their carers.

Emotional face recognition deficits and medication effects in pre-manifest through stage-II Huntington's disease

Facial emotion recognition impairments have been reported in Huntington's disease (HD). However, the nature of the impairments across the spectrum of HD remains unclear. We report on emotion recognition data from 344 participants comprising premanifest HD (PreHD) and early HD patients, and controls. In a test of recognition of facial emotions, we examined responses to six basic emotional expressions and neutral expressions. In addition, and within the early HD sample, we tested for differences on emotion recognition performance between those 'on' vs. 'off' neuroleptic or selective serotonin reuptake inhibitor (SSRI) medications. The PreHD groups showed significant (p<0.05) impaired recognition, compared to controls, on fearful, angry and surprised faces; whereas the early HD groups were significantly impaired across all emotions including neutral expressions. In early HD, neuroleptic use was associated with worse facial emotion recognition, whereas SSRI use was associated with better facial emotion recognition. The findings suggest that emotion recognition impairments exist across the HD spectrum, but are relatively more widespread in manifest HD than in the premanifest period. Commonly prescribed medications to treat HD-related symptoms also appear to affect emotion recognition. These findings have important implications for interpersonal communication and medication usage in HD.

Neural correlates of impaired emotion processing in manifest Huntington's disease

The complex phenotype of Huntington's disease (HD) encompasses motor, psychiatric and cognitive dysfunctions, including early impairments in emotion recognition. In this first functional magnetic resonance imaging study, we investigated emotion-processing deficits in 14 manifest HD patients and matched controls. An emotion recognition task comprised short video clips displaying one of six basic facial expressions (sadness, happiness, disgust, fear, anger and neutral). Structural changes between patients and controls were assessed by means of voxel-based morphometry. Along with deficient recognition of negative emotions, patients exhibited predominantly lower neural response to stimuli of negative valences in the amygdala, hippocampus, striatum, insula, cingulate and prefrontal cortices, as well as in sensorimotor, temporal and visual areas. Most of the observed reduced activity patterns could not be explained merely by regional volume loss. Reduced activity in the thalamus during fear correlated with lower thalamic volumes. During the processing of sadness, patients exhibited enhanced amygdala and hippocampal activity along with reduced recruitment of the medial prefrontal cortex. Higher amygdala activity was related to more pronounced amygdala atrophy and disease burden. Overall, the observed emotion-related dysfunctions in the context of structural neurodegeneration suggest both disruptions of striatal-thalamo-cortical loops and potential compensation mechanism with greater disease severity in manifest HD.

Emotional blunting following left basal ganglia stroke: the role of depression and fronto-limbic functional alterations

Disorders of the basal ganglia (BG) alter perception and experience of emotions. Left hemisphere BG (LBG) stroke is also associated with depression. The interplay between depression and alterations in emotional processing following LBG stroke was examined. Evoked affective responses to emotion-laden pictorial stimuli were compared among LBG stroke and healthy participants and participants with stroke damage in brain regions not including the LBG selected to equate depression severity (measured using the Hamilton Depression Scale) with LBG damage participants. Brain activity {[O(15)]water positron emission tomography, PET} was measured in LBG stroke relative to healthy participants to identify changes in regions associated with emotion processing and depression. LBG stroke subjects reported less intense emotions compared with healthy, but not stroke comparison participants. Depression negatively correlated with emotional experience for positive and negative emotions. In response to positive stimuli, LBG subjects exhibited higher activity in amygdala, anterior cingulate, dorsal prefrontal cortex, and insula compared to healthy volunteers. In response to negative stimuli, LBG subjects demonstrated lower activity in right frontal-polar region and fusiform gyrus. Higher baseline activity in amygdala and ventral and mesial prefrontal cortex and lower activity in left dorsal lateral prefrontal cortex were associated with higher depression scores. LBG stroke led to blunted emotions, and brain activity alterations accounting for reduced affective experience, awareness and depression. Depression and fronto-limbic activity changes may contribute to emotional blunting following LBG stroke.

Inherently Ambiguous: Facial Expressions of Emotions, in Context

With a few yet increasing number of exceptions, the cognitive sciences enthusiastically endorsed the idea that there are basic facial expressions of emotions that are created by specific configurations of facial muscles. We review evidence that suggests an inherent role for context in emotion perception. Context does not merely change emotion perception at the edges; it leads to radical categorical changes. The reviewed findings suggest that configurations of facial muscles are inherently ambiguous, and they call for a different approach towards the understanding of facial expressions of emotions. Prices of sticking with the modal view, and advantages of an expanded view, are succinctly reviewed.

General and specific abilities to recognise negative emotions, especially disgust, as portrayed in the face and the body

We examined the ability of 150-166 undergraduate students to assign four negative emotions (sadness, fear, disgust, and anger) to five sets of emotion expression stimuli: a standard of face photographs expressing basic emotions, faces that were morphs of standards for these emotions, a special set of faces that was designed to detect different components of disgust expressions, and two sets of dynamic, video clips displays of emotions as described in traditional Hindu scriptures and used in classical Hindu dance. One of these sets presented the full body traditional displays (including hands and face), while in the second set, the same clips were used but the facial expressions were blocked out. Participants also completed an obsessive compulsive inventory and the disgust scale. Major findings are that: (a) there are some substantial individual differences in ability to correctly identify emotions; (b) the ability to detect facial emotions correlates substantially (.49) with ability to detect bodily emotions; (c) there is no evidence for specific deficits in the detection of any particular emotion; and (d) there is no relation between individual differences in obsessive-compulsive disorder (OCD) tendencies or disgust sensitivity, in a normal sample and the ability to detect disgust.

Cognitive functions and corticostriatal circuits: insights from Huntington's disease

The basic mechanisms of information processing by corticostriatal circuits are currently a matter of intense debate amongst cognitive scientists. Huntington's disease, an autosomal-dominant neurogenetic disorder characterized clinically by a triad of motor, cognitive, and affective disturbance, is associated with neuronal loss within corticostriatal circuits, and as such provides a valuable model for understanding the role of these circuits in normal behaviour, and their disruption in disease. We review findings from our studies of the breakdown of cognition in Huntington's disease, with a particular emphasis on executive functions and visual recognition memory. We show that Huntington's disease patients exhibit a neuropsychological profile that shows a discernible pattern of progression with advancing disease, and appears to result from a breakdown in the mechanisms of response selection. These findings are consistent with recent computational models that suggest that corticostriatal circuits compute the patterns of sensory input and response output which are of behavioural significance within a particular environmental context.

Altered brain mechanisms of emotion processing in pre-manifest Huntington's disease

Huntington's disease is an inherited neurodegenerative disease that causes motor, cognitive and psychiatric impairment, including an early decline in ability to recognize emotional states in others. The pathophysiology underlying the earliest manifestations of the disease is not fully understood; the objective of our study was to clarify this. We used functional magnetic resonance imaging to investigate changes in brain mechanisms of emotion recognition in pre-manifest carriers of the abnormal Huntington's disease gene (subjects with pre-manifest Huntington's disease): 16 subjects with pre-manifest Huntington's disease and 14 control subjects underwent 1.5 tesla magnetic resonance scanning while viewing pictures of facial expressions from the Ekman and Friesen series. Disgust, anger and happiness were chosen as emotions of interest. Disgust is the emotion in which recognition deficits have most commonly been detected in Huntington's disease; anger is the emotion in which impaired recognition was detected in the largest behavioural study of emotion recognition in pre-manifest Huntington's disease to date; and happiness is a positive emotion to contrast with disgust and anger. Ekman facial expressions were also used to quantify emotion recognition accuracy outside the scanner and structural magnetic resonance imaging with voxel-based morphometry was used to assess the relationship between emotion recognition accuracy and regional grey matter volume. Emotion processing in pre-manifest Huntington's disease was associated with reduced neural activity for all three emotions in partially separable functional networks. Furthermore, the Huntington's disease-associated modulation of disgust and happiness processing was negatively correlated with genetic markers of pre-manifest disease progression in distributed, largely extrastriatal networks. The modulated disgust network included insulae, cingulate cortices, pre- and postcentral gyri, precunei, cunei, bilateral putamena, right pallidum, right thalamus, cerebellum, middle frontal, middle occipital, right superior and left inferior temporal gyri, and left superior parietal lobule. The modulated happiness network included postcentral gyri, left caudate, right cingulate cortex, right superior and inferior parietal lobules, and right superior frontal, middle temporal, middle occipital and precentral gyri. These effects were not driven merely by striatal dysfunction. We did not find equivalent associations between brain structure and emotion recognition, and the pre-manifest Huntington's disease cohort did not have a behavioural deficit in out-of-scanner emotion recognition relative to controls. In addition, we found increased neural activity in the pre-manifest subjects in response to all three emotions in frontal regions, predominantly in the middle frontal gyri. Overall, these findings suggest that pathophysiological effects of Huntington's disease may precede the development of overt clinical symptoms and detectable cerebral atrophy.

Emotional arousal and multiple memory systems in the mammalian brain

Emotional arousal induced by stress and/or anxiety can exert complex effects on learning and memory processes in mammals. Recent studies have begun to link study of the influence of emotional arousal on memory with earlier research indicating that memory is organized in multiple systems in the brain that differ in terms of the "type" of memory they mediate. Specifically, these studies have examined whether emotional arousal may have a differential effect on the "cognitive" and stimulus-response "habit" memory processes sub-served by the hippocampus and dorsal striatum, respectively. Evidence indicates that stress or the peripheral injection of anxiogenic drugs can bias animals and humans toward the use of striatal-dependent habit memory in dual-solution tasks in which both hippocampal and striatal-based strategies can provide an adequate solution. A bias toward the use of habit memory can also be produced by intra-basolateral amygdala (BLA) administration of anxiogenic drugs, consistent with the well documented role of efferent projections of this brain region in mediating the modulatory influence of emotional arousal on memory. In some learning situations, the bias toward the use of habit memory produced by emotional arousal appears to result from an impairing effect on hippocampus-dependent cognitive memory. Further research examining the neural mechanisms linking emotion and the relative use of multiple memory systems should prove useful in view of the potential role for maladaptive habitual behaviors in various human psychopathologies.

Ew gross! Recognition of Expressions of Disgust by Children With Obsessive–Compulsive Disorder

There is evidence suggesting that obsessive–compulsive disorder (OCD) in adults may be associated with an impaired ability to recognise the facial expression of disgust (Sprengelmeyer et al., 1997a; Woody, Corcoran, & Tolin, in press). It has been suggested that this impairment begins in childhood when the recognition of emotional expressions is being learnt (see Spengelmeyer et al., 1997a). This study compared the recognition of facial affect in children aged around 11 years with a diagnosis of obsessive–compulsive disorder (OCD; n = 11), other anxiety disorders (n = 20), and nonclinical children (n = 19), adapting the methodology of Sprengelmeyer et al. Disgust was most commonly misclassified as anger by children in all three groups. However, children with OCD did not show any evidence of a recognition deficit for disgust in comparison to either control group. Unexpectedly, however, children with OCD recognised expressions of surprise more accurately than nonclinical children. Recognition of disgust or any other emotion was not related to child self-reported anxiety symptoms. Given the observed differences in some studies with adults, future research may benefit by examining older adolescents and young adults to determine when these effects may first be noticed.

Scanning Patterns of Faces do not Explain Impaired Emotion Recognition in Huntington Disease: Evidence for a High Level Mechanism

In the current study, we aimed to investigate the emotion recognition impairment in Huntington’s disease (HD) patients and define whether this deficit is caused by impaired scanning patterns of the face. To achieve this goal, we recorded eye movements during a two-alternative forced-choice emotion recognition task. HD patients in pre-symptomatic (n = 16) and symptomatic (n = 9) disease stages were tested and their performance was compared to a control group (n = 22). In our emotion recognition task, participants had to indicate whether a face reflected one of six basic emotions. In addition, and in order to define whether emotion recognition was altered when the participants were forced to look at a specific component of the face, we used a second task where only limited facial information was provided (eyes/mouth in partially masked faces). Behavioral results showed no differences in the ability to recognize emotions between pre-symptomatic gene carriers and controls. However, an emotion recognition deficit was found for all six basic emotion categories in early stage HD. Analysis of eye movement patterns showed that patient and controls used similar scanning strategies. Patterns of deficits were similar regardless of whether parts of the faces were masked or not, thereby confirming that selective attention to particular face parts is not underlying the deficits. These results suggest that the emotion recognition deficits in symptomatic HD patients cannot be explained by impaired scanning patterns of faces. Furthermore, no selective deficit for recognition of disgust was found in pre-symptomatic HD patients.

Understanding disgust

Disgust is characterized by a remarkably diverse set of stimulus triggers, ranging from extremely concrete (bad tastes and disease vectors) to extremely abstract (moral transgressions and those who commit them). This diversity may reflect an expansion of the role of disgust over evolutionary time, from an origin in defending the body against toxicity and disease, through defense against other threats to biological fitness (e.g., incest), to involvement in the selection of suitable interaction partners, by motivating the rejection of individuals who violate social and moral norms. The anterior insula, and to a lesser extent the basal ganglia, are implicated in toxicity- and disease-related forms of disgust, although we argue that insular activation is not exclusive to disgust. It remains unclear whether moral disgust is associated with insular activity. Disgust offers cognitive neuroscientists a unique opportunity to study how an evolutionarily ancient response rooted in the chemical senses has expanded into a uniquely human social cognitive domain; many interesting research avenues remain to be explored.

Emotion recognition and experience in Huntington disease: a voxel-based morphometry study

BACKGROUND

The neuroanatomic basis of affective processing deficits in Huntington disease is insufficiently understood. We investigated whether Huntington disease-related deficits in emotion recognition and experience are associated with specific changes in grey matter volume.

METHOD

We assessed grey matter volume in symptomatic patients with Huntington disease and healthy controls using voxel-based morphometry, and we correlated regional grey matter volume with participants' affective ratings.

RESULTS

We enrolled 18 patients with Huntington disease and 18 healthy controls in our study. Patients with Huntington disease showed normal affective experience but impaired recognition of negative emotions (disgust, anger, sadness). The patients perceived the emotions as less intense and made more classification errors than controls. These deficits were correlated with regional atrophy in emotion-relevant areas (insula, orbitofrontal cortex) and in memory-relevant areas (dorsolateral prefrontal cortex, hippocampus).

LIMITATIONS

Our study was limited by the small sample size and the resulting modest statistical power relative to the number of tests.

CONCLUSION

Our study sheds new light on the importance of a cognitive-affective brain circuit involved in the affect recognition impairment in patients with Huntington disease.

Sad or fearful? The influence of body posture on adults' and children's perception of facial displays of emotion

The current research investigated the influence of body posture on adults' and children's perception of facial displays of emotion. In each of two experiments, participants categorized facial expressions that were presented on a body posture that was congruent (e.g., a sad face on a body posing sadness) or incongruent (e.g., a sad face on a body posing fear). Adults and 8-year-olds made more errors and had longer reaction times on incongruent trials than on congruent trials when judging sad versus fearful facial expressions, an effect that was larger in 8-year-olds. The congruency effect was reduced when faces and bodies were misaligned, providing some evidence for holistic processing. Neither adults nor 8-year-olds were affected by congruency when judging sad versus happy expressions. Evidence that congruency effects vary with age and with similarity of emotional expressions is consistent with dimensional theories and "emotional seed" models of emotion perception.

Basic Emotion Questions

Among discrete emotions, basic emotions are the most elemental; most distinct; most continuous across species, time, and place; and most intimately related to survival-critical functions. For an emotion to be afforded basic emotion status it must meet criteria of: (a) distinctness (primarily in behavioral and physiological characteristics), (b) hard-wiredness (circuitry built into the nervous system), and (c) functionality (provides a generalized solution to a particular survival-relevant challenge or opportunity). A set of six emotions that most clearly meet these criteria (enjoyment, anger, disgust, fear, surprise, sadness) and three additional emotions (relief/contentment, interest, love) for which the evidence is not yet quite as strong is described. Empirical approaches that are most and least useful for establishing basic-emotion status are discussed. Basic emotions are thought to have a central organizing mechanism and to have the capacity to influence behavior, thoughts, and other fundamental processes.

Emotion recognition and experience in Huntington's disease: is there a differential impairment?

Findings on affective processing deficits in Huntington's disease (HD) have been inconsistent. It is still not clear whether HD patients are afflicted by specific deficits in emotion recognition and experience. We tested 28 symptomatic HD patients and presented them with pictures depicting facial expressions of emotions (Karolinska-Set) and with affective scenes (International Affective Picture System; IAPS). The faces were judged according to the displayed intensity of six basic emotions, whereas the scenes received intensity ratings for the elicited emotions in the viewer. Patients' responses were compared with those of 28 healthy controls. HD patients gave lower intensity ratings for facial expressions of anger, disgust and surprise than controls. Patients' recognition deficits were associated with reduced functional capacity, such as problems with social interactions. Moreover, their classification accuracy was reduced for angry, disgusted, sad and surprised faces. When judging affective scenes for the elicitation of happiness, disgust and fear, HD patients had a tendency to estimate them as more intense than controls. This finding points to a differential impairment in emotion recognition and emotion experience in HD. We found no significant correlations between emotion experience/recognition ratings and CAG repeats, symptom duration and UHDRS Motor Assessment in the patient group.