Beyond emotion recognition deficits: A theory guided analysis of emotion processing in Huntington’s disease

Delineating the neural substrates of autobiographical memory impairment in Huntington's disease

Emerging evidence suggests that autobiographical memory (ABM) is altered in Huntington's disease (HD). While these impairments are typically attributed to frontostriatal dysfunction, the neural substrates of ABM impairment in HD remain unexplored. To this end, we assessed ABM in 30 participants with genetically confirmed HD (18 premanifest, 12 manifest) and 24 age-matched healthy controls. Participants completed the Autobiographical Interview to assess free and probed ABM recall and underwent structural brain imaging. Whole-brain voxel-based morphometry (VBM) was used to explore voxel-wise associations between ABM performance and grey matter intensity (False Discovery Rate corrected at q = 0.05). Relative to controls, HD participants displayed significantly less detailed ABM retrieval across free and probed recall conditions, irrespective of disease stage. Recall performance did not differ significantly between manifest and premanifest HD groups. VBM analyses indicated that poorer ABM performance was associated with atrophy of a distributed cortico-subcortical network. Key regions implicated irrespective of ABM condition included the bilateral occipital cortex, left precuneus, right parahippocampal gyrus and right caudate nucleus. In addition, probed ABM recall was associated with the superior and inferior frontal gyri, frontal pole, right hippocampus, nucleus accumbens, paracingulate gyrus and cerebellum. Overall, our findings indicate that ABM impairments in HD reflect the progressive degeneration of a distributed cortico-subcortical brain network comprising medial temporal, frontal, striatal and posterior parietal cortices. Our findings advance our understanding of the neurocognitive profile of HD, providing an important foundation for future interventions to support memory function in this population.

Huntington study group's neuropsychology working group position on best practice recommendations for the clinical neuropsychological evaluation of patients with Huntington disease

Objective: Neuropsychological evaluation is critical to detection and management of cognitive and neuropsychiatric changes associated with Huntington disease (HD). Accurate assessment of non-motor complications of HD is critical given the prominent impact on functional disability, frequently commensurate with or exceeding that of motor symptoms. The increasing emphasis on developing disease-modifying therapies targeting cognitive decline in HD requires consensus on clinical neuropsychological assessment methods. The Neuropsychology Working Group (NPWG) of the Huntington Study Group (HSG) sought to provide evidence and consensus-based, practical guidelines for the evaluation of cognitive and neuropsychiatric symptoms associated with HD. Method: The NPWG recruited a multi-disciplinary group of neuropsychologists, neurologists, and psychiatrists to inform best practices in assessing, diagnosing, and treating the non-motor symptoms in HD. A review was circulated among the NPWG, and in an iterative process informed by reviewed literature, best practices in neuropsychological evaluation of patients with HD were identified. Results: A brief review of the available literature and rational for a clinical consensus battery is offered. Conclusion: Clinical neuropsychologists are uniquely positioned to both detect and characterize the non-motor symptoms in HD, and further, provide neurologists and allied health professions with clinically meaningful information that impacts functional outcomes and quality of life. The NPWG provides guidance on best practices to clinical neuropsychologists in this statement. A companion paper operationalizing clinical application of previous research-based non-motor diagnostic criteria for HD is forthcoming, which also advises on non-motor symptom screening methods for the non-neuropsychologist working with HD.

Can the Ability to Recognize Facial Emotions in Individuals With Neurodegenerative Disease be Improved? A Systematic Review and Meta-analysis

BACKGROUND

Facial emotion recognition (FER) is commonly impaired in individuals with neurodegenerative disease (NDD). This impairment has been linked to an increase in behavioral disorders and caregiver burden.

OBJECTIVE

To identify interventions targeting the improvement of FER ability in individuals with NDD and investigate the magnitude of the efficacy of the interventions. We also wanted to explore the duration of the effects of the intervention and their possible impacts on behavioral and psychological symptoms of dementia and caregiver burden.

METHOD

We included 15 studies with 604 individuals who had been diagnosed with NDD. The identified interventions were categorized into three types of approach (cognitive, neurostimulation, and pharmacological) as well as a combined approach (neurostimulation with pharmacological).

RESULTS

The three types of approaches pooled together had a significant large effect size for FER ability improvement (standard mean difference: 1.21, 95% CI = 0.11, 2.31, z = 2.15, P = 0.03). The improvement lasted post intervention, in tandem with a decrease in behavioral disorders and caregiver burden.

CONCLUSION

A combination of different approaches for FER ability improvement may be beneficial for individuals with NDD and their caregivers.

Disgust as a transdiagnostic index of mental illness: A narrative review of clinical populations

Disgust is a basic emotion of rejection, providing an ancestral defensive mechanism against illness. Based on research that documents altered experiences of disgust across several psychopathological conditions, we conducted a narrative review to address the hypothesis that altered disgust may serve as a transdiagnostic index of mental illness. Our synthesis of the literature from past decades suggests that, compared to healthy populations, patients with mental disorders exhibit abnormal processing of disgust in at least one of the analyzed dimensions. We also outline evidence of alterations in brain areas relevant to disgust processing, such as the insula and the interconnected limbic network. Overall, we provide preliminary support for the hypothesis that altered disgust processing may serve as a transdiagnostic index of mental illness.

Decreased CSF oxytocin relates to measures of social cognitive impairment in Huntington's disease patients

OBJECTIVE

Huntington's disease (HD) is an inherited neurodegenerative disease with motor, cognitive and psychiatric symptoms. Non-motor symptoms like depression and altered social cognition are proposed to be caused by dysfunction of the hypothalamus. We measured the hypothalamic neuropeptide oxytocin in plasma and cerebrospinal fluid (CSF) in a cohort of HD gene expansion carriers (HDGECs), compared the levels to healthy HD family controls and correlated oxytocin levels to disease progression and social cognition.

METHODS

We recruited 113 HDGECs and 33 controls. Psychiatric and cognitive symptoms were evaluated, and social cognition was assessed with the Emotion Hexagon test, Reading the Mind in the Eyes and The Awareness of Social Inference Test. The levels of oxytocin in CSF and blood were analyzed by radioimmunoassay.

RESULTS

We found the level of oxytocin in CSF to be significantly lower by 33.5% in HDGECs compared to controls (p = 0.016). When dividing the HDGECs into groups with or without cognitive impairment, we found the oxytocin level to be significantly lower by 30.3% in the HDGECs with cognitive symptoms (p = 0.046). We found a statistically significant correlation between the level of oxytocin and scores on social cognition (Reading the Mind in the Eyes p = 0.0019; Emotion Hexagon test: p = 0.0062; The Awareness of Social Inference Test: p = 0.002).

CONCLUSIONS

This is the first study to measure oxytocin in the CSF of HDGECs. We find that HDGECs have a significantly lower level of oxytocin compared to controls, and that the level of oxytocin may represent an objective and comparable measure that could be used as a state biomarker for impairment of social cognition. We suggest treatment trials to evaluate a potential effect of oxytocin on social cognition in HD.

Research on Emotion Recognition and Dementias: Foundations and Prospects

BACKGROUND

The study of emotion recognition could be crucial for detecting alterations in certain cognitive areas or as an early sign of neurological disorders.

OBJECTIVE

The main objective of the study is to characterize research development on emotion recognition, identifying the intellectual structure that supports this area of knowledge, and the main lines of research attracting investigators' interest.

METHODS

We identified publications on emotion recognition and dementia included in the Web of Science Core Collection, analyzing the scientific output and main disciplines involved in generating knowledge in the area. A co-citation analysis and an analysis of the bibliographic coupling between the retrieved documents elucidated the thematic orientations of the research and the reference works that constitute the foundation for development in the field.

RESULTS

A total of 345 documents, with 24,282 bibliographic references between them, were included. This is an emerging research area, attracting the interest of investigators in Neurosciences, Psychology, Clinical Neurology, and Psychiatry, among other disciplines. Four prominent topic areas were identified, linked to frontotemporal dementia, autism spectrum disorders, Alzheimer's disease, and Parkinson's and Huntington disease. Many recent papers focus on the detection of mild cognitive impairment.

CONCLUSION

Impaired emotion recognition may be a key sign facilitating the diagnosis and early treatment of different neurodegenerative diseases as well as for triggering the necessary provision of social and family support, explaining the growing research interest in this area.

Mood and emotional disorders associated with parkinsonism, Huntington disease, and other movement disorders

This chapter provides a review of mood, emotional disorders, and emotion processing deficits associated with diseases that cause movement disorders, including Parkinson's disease, Lewy body dementia, multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, frontotemporal dementia with parkinsonism, Huntington's disease, essential tremor, dystonia, and tardive dyskinesia. For each disorder, a clinical description of the common signs and symptoms, disease progression, and epidemiology is provided. Then the mood and emotional disorders associated with each of these diseases are described and discussed in terms of clinical presentation, incidence, prevalence, and alterations in quality of life. Alterations of emotion communication, such as affective speech prosody and facial emotional expression, associated with these disorders are also discussed. In addition, if applicable, deficits in gestural and lexical/verbal emotion are reviewed. Throughout the chapter, the relationships among mood and emotional disorders, alterations of emotional experiences, social communication, and quality of life, as well as treatment, are emphasized.

Abnormal visual scanning and impaired mental state recognition in pre-manifest Huntington disease

Huntington's disease (HD) is a genetic neurodegenerative disorder that affects not only the motor but also the cognitive and the neuropsychiatric domain. In particular, deficits in mental state recognition may emerge already at early pre-manifest stages of the disease. The aim of this research was to explore the relation between visual scanning behavior and complex mental state recognition in individuals with pre-manifest HD (preHD). Eighteen preHD and eighteen age- and gender-matched healthy controls took the revised "Reading the Mind in the Eyes" test while their eye-movements were tracked. In addition to the expected deficits in mental state recognition, preHD showed abnormalities concerning all three scanning variables we considered, namely the absolute number of fixations (FC), the average fixation duration (AFD), and the percentage of time spent fixating (FTR). In preHD, FC and FTR but not AFD predicted mental state recognition over and beyond general disease-related declines in cognition and motor functioning. Notably, preHD showed abnormal vertical and horizontal fixation patterns, and these patterns predicted mental state recognition, suggesting the involvement of mechanisms related to the embodied processing of emotional stimuli. Overall, our results suggest that impaired facial mental state recognition in pre-manifest HD is partly due to emotional-motivational factors affecting the visual scanning of facial expressions.

Social Cognition in a Research Domain Criteria Perspective: A Bridge Between Schizophrenia and Autism Spectra Disorders

Schizophrenia and autism spectra disorders are currently conceptualized as distinct clinical categories. However, the relationship between these two nosological entities has been revisited in recent years due to the evidence that they share some important clinical and neurobiological features, putting into question the nature and the extent of their commonalities and differences. In this respect, some core symptoms that are present in both disorders, such as social cognitive deficits, could be a primary target of investigation. This review briefly summarizes the commonalities and overlapping features between schizophrenia and autism spectra disorders in social cognitive functions, considering this construct in a Research Domain Criteria perspective. The clinical manifestation of deficits in social cognition are similar in schizophrenia spectrum disorders and autism spectrum disorders, and brain areas that appear to be altered in relation to these impairments are largely shared; however, the results of various studies suggest that, in some cases, the qualitative nature of these alterations may be different in the two spectra. Moreover, relevant differences could be present at the level of brain networks and connections. More research is required in this field, regarding molecular and genetic aspects of both spectra, to better define the neurobiological mechanisms involved in social cognition deficits, with the objective of developing specific and targeted treatments.

A sensorimotor control framework for understanding emotional communication and regulation

Our research team was asked to consider the relationship of the neuroscience of sensorimotor control to the language of emotions and feelings. Actions are the principal means for the communication of emotions and feelings in both humans and other animals, and the allostatic mechanisms controlling action also apply to the regulation of emotional states by the self and others. We consider how motor control of hierarchically organised, feedback-based, goal-directed action has evolved in humans, within a context of consciousness, appraisal and cultural learning, to serve emotions and feelings. In our linguistic analysis, we found that many emotion and feelings words could be assigned to stages in the sensorimotor learning process, but the assignment was often arbitrary. The embodied nature of emotional communication means that action words are frequently used, but that the meanings or senses of the word depend on its contextual use, just as the relationship of an action to an emotion is also contextually dependent.

Visual Object Perception in Premanifest and Early Manifest Huntington's Disease

OBJECTIVE

In Huntington's disease (HD), a hereditary neurodegenerative disorder, cognitive impairment in early disease stages mainly involves executive dysfunction. However, visual cognitive deficits have additionally been reported and are of clinical relevance given their influence on daily life and overall cognitive performance. This study aimed to assess visual perceptual skills in HD gene carriers.

METHODS

Subtasks of the Visual Object and Space Perception battery and Groningen Intelligence Test were administered in 62 participants (18 healthy controls, 22 participants with a genetic confirmation of HD without symptoms, i.e., premanifest HD, and 22 participants with a genetic confirmation of HD with symptoms, i.e., manifest HD). Group differences in task performance were measured using analysis of covariance with and without correction for age. Receiver Operating Characteristics (ROC) analysis was performed to examine which task best discriminated between groups and cut-off scores were provided.

RESULTS

Manifest HD performed significantly worse compared to both controls and premanifest HD on all visual perceptional tasks. Premanifest HD did not differ in task performance from controls. Besides the Shape Detection, all tasks were robust in discriminating between groups. The Animal Silhouettes test was most accurate in discriminating manifest HD from premanifest HD (AUC = 0.90, SE = 0.048, p < .001).

CONCLUSION

Visual perceptual deficits are present in early manifest HD, especially an impaired recognition of animals and objects from sketched silhouettes, and not in premanifest HD. This suggests that decline in visual processing only occurs in clinical disease stages. The visual cognitive battery, especially the Silhouettes tasks used in this study is sensitive in discriminating manifest HD from premanifest HD and controls.

Deep Learning of Empirical Mean Curve Decomposition-Wavelet Decomposed EEG Signal for Emotion Recognition

Recently, the emotional state recognition of humans via Electroencephalogram (EEG) is one of the emerging topics that grasp the attention of researchers too. This EEG based recognition is normally an effective model for many of the real-time applications, especially for disabled people. A number of researchers are in progress to make the recognition model more effective in terms of accurate emotion recognition. However, it is not so satisfactory in the precise accurate progressing. Hence this paper intends to recognize the human emotional states or affects through EEG signals by adopting advanced features and classifier models. In the first stage of recognition procedure, this paper exploits 2501 (EMCD) and Wavelet Transformation to represent the EEG signal in low dimension as well as descriptive. By EMCD, the EEG redundancy can be neglected, and the significant information can be extracted. The classification processes using the extracted features with the aid of a classifier named Deep Belief Network (DBN). The performance of the proposed Wavelet-EMCD (WE) approach is analyzed in terms of measures such as Accuracy, Sensitivity, Specificity, Precision, False positive rate (FPR), False negative rate (FNR), Negative Predictive Value (NPV), False Discovery Rate (FDR), F1Score and Mathews correlation coefficient (MCC) and proven the superiority of proposed work in recognizing the emotions more accurately.

Emotion recognition and inhibitory control in manifest and pre-manifest Huntington's disease: evidence from a new Stroop task

Huntington's disease (HD) is a genetic neurodegenerative disorder that affects not only the motor but also the cognitive domain. In particular, cognitive symptoms such as impaired executive skills and deficits in recognizing other individuals' mental state may emerge many years before the motor symptoms. This study was aimed at testing two cognitive hypotheses suggested by previous research with a new Stroop task created for the purpose: 1) the impairment of emotion recognition in HD is moderated by the emotions' valence, and 2) inhibitory control is impaired in HD. Forty manifest and 20 pre-manifest HD patients and their age- and gender-matched controls completed both the traditional "Stroop Color and Word Test" (SCWT) and the newly created "Stroop Emotion Recognition under Word Interference Task" (SERWIT), which consist in 120 photographs of sad, calm, or happy faces with either congruent or incongruent word interference. On the SERWIT, impaired emotion recognition in manifest HD was moderated by emotion type, with deficits being larger in recognizing sadness and calmness than in recognizing happiness, but it was not moderated by stimulus congruency. On the SCWT, six different interference scores yielded as many different patterns of group effects. Overall our results corroborate the hypothesis that impaired emotion recognition in HD is moderated by the emotions' valence, but do not provide evidence for the hypothesis that inhibitory control is impaired in HD. Further research is needed to learn more about the psychological mechanisms underlying the moderating effect of emotional valence on impaired emotion recognition in HD, and to corroborate the hypothesis that the inhibitory processes involved in Stroop tasks are not impaired in HD. Looking beyond this study, the SERWIT promises to make important contributions to disentangling the cognitive and the psychomotor aspects of neurological disorders. The research was approved by the Ethics Committee of the "Istituto Leonarda Vaccari", Rome on January 24, 2018.

Discrete changes in the frequency and functions of autobiographical reminiscence in Huntington's disease

Autobiographical memory is widely posited to serve self, social and directive functions. Recent evidence suggests marked autobiographical memory impairments in Huntington's disease (HD), however, no study to date has determined how the perceived functions of autobiographical reminiscence may be altered in HD. The current study aimed to assess the self-reported frequency and function of autobiographical reminiscence in HD. We assessed autobiographical reminiscence in late premanifest (n = 16) and early stage HD (n = 14), relative to healthy controls (n = 30). Participants completed the Thinking About Life Experiences Scale Revised (TALE-R), which measures three putative functions of autobiographical memory (self, social, directive). People with manifest HD reported talking less frequently about the past compared to controls. In contrast, no group differences were found in terms of thinking about the past. Manifest HD participants further reported using their autobiographical memories for social functions less frequently compared to controls. No other group differences were evident in terms of self or directive functions of autobiographical memory. These self-report findings complement recent reports of autobiographical memory disruption on performance-based tasks in HD. Future studies exploring how changes in autobiographical reminiscence impact a sense of self continuity in HD will be important in this regard.

Apathy Associated With Impaired Recognition of Happy Facial Expressions in Huntington's Disease

OBJECTIVES

Previous research has demonstrated an association between emotion recognition and apathy in several neurological conditions involving fronto-striatal pathology, including Parkinson's disease and brain injury. In line with these findings, we aimed to determine whether apathetic participants with early Huntington's disease (HD) were more impaired on an emotion recognition task compared to non-apathetic participants and healthy controls.

METHODS

We included 43 participants from the TRACK-HD study who reported apathy on the Problem Behaviours Assessment - short version (PBA-S), 67 participants who reported no apathy, and 107 controls matched for age, sex, and level of education. During their baseline TRACK-HD visit, participants completed a battery of cognitive and psychological tests including an emotion recognition task, the Hospital Depression and Anxiety Scale (HADS) and were assessed on the PBA-S.

RESULTS

Compared to the non-apathetic group and the control group, the apathetic group were impaired on the recognition of happy facial expressions, after controlling for depression symptomology on the HADS and general disease progression (Unified Huntington's Disease Rating Scale total motor score). This was despite no difference between the apathetic and non-apathetic group on overall cognitive functioning assessed by a cognitive composite score.

CONCLUSIONS

Impairment of the recognition of happy expressions may be part of the clinical picture of apathy in HD. While shared reliance on frontostriatal pathways may broadly explain associations between emotion recognition and apathy found across several patient groups, further work is needed to determine what relationships exist between recognition of specific emotions, distinct subtypes of apathy and underlying neuropathology. (JINS, 2019, 25, 453-461).

Pervasive autobiographical memory impairments in Huntington's disease

Autobiographical memory dysfunction is a pervasive feature of neurodegenerative disorders, but less is known about the integrity of autobiographical memory in Huntington's disease (HD). Deficits in anterograde verbal episodic memory on traditional neuropsychological tests have been detected in HD, however, whether personally-relevant autobiographical retrieval is also affected is unknown. We examined autobiographical memory performance in 26 participants genetically confirmed to have HD who were in the peri-manifest stage of the disease (including 12 in the late premanifest stage and 14 who were early diagnosed), and 24 matched controls using the Autobiographical Interview (AI), a semi-structured interview assessing retrieval of autobiographical details from discrete epochs across the lifetime. Relative to controls, people with HD exhibited global episodic autobiographical memory impairments, regardless of recency or remoteness of the memory being retrieved. While specific cues bolstered the retrieval of episodic (internal) details in HD participants, their performance remained significantly below that of controls. Moreover, following probing, people with HD retrieved more extraneous (external) details not directly related to the autobiographical event they originally retrieved, including semantic details, repetitions, and metacognitive statements. Our results reveal marked autobiographical memory dysfunction in HD, not directly attributable to strategic retrieval deficits, and suggest that autobiographical memory impairment may represent an overlooked feature of the cognitive phenotype of HD.

Structural and functional changes of the visual cortex in early Huntington's disease

Huntington's disease (HD) is an autosomal-dominant inherited neurodegenerative disorder characterized by motor disturbances, psychiatric disturbances, and cognitive impairment. Visual cognitive deficits and atrophy of the posterior cerebral cortex are additionally present in early disease stages. This study aimed to assess the extent of structural and functional brain alterations of the visual cortex in HD gene carriers using different neuroimaging modalities. Structural and functional magnetic resonance imaging data were acquired from 18 healthy controls, 21 premanifest, and 20 manifest HD gene carriers. Voxel-based morphometry (VBM) analysis and cortical thickness measurements were performed to assess structural changes in the visual cortex. Brain function was measured by assessing neuronal connectivity changes in response to visual stimulation and at rest in visual resting-state networks. Multiple linear regression analyses were performed to examine the relationship between visual cognitive function and structural imaging measures. Compared to controls, pronounced atrophy and decreased neuronal function at rest were present in associative visual cortices in manifest HD. The primary visual cortex did not show group differences in cortical thickness and in vascular activity after visual stimulation. Thinning of the associative visual cortex was related to worse visual perceptual function. Premanifest HD gene carriers did not show any differences in brain structure or function compared to controls. This study improves the knowledge on posterior brain changes in HD, as our findings suggest that the primary visual cortex remains preserved, both structurally and functionally, while atrophy of associative visual cortices is present in early HD and linked to clinical visual deficits.

Social Cognition and Oxytocin in Huntington's Disease: New Insights

This study is aimed at relating social cognition in Huntington's Disease (HD) to plasma levels of the social hormone oxytocin (OT). Indeed, HD patients commonly display reduced social skills and OT is involved in bonding behavior and improved recognition of facial emotions. Twelve mild-symptomatic HD patients (stage II Shoulson &amp; Fahn) and 11 gender/age matched controls (healthy controls, HC), without concurrent psychiatric disorders, were investigated at baseline (T₀) for OT plasma levels and social cognition through an extensive battery of neuropsychological tests. Social cognition was also re-examined after two years (T1) in 8 of the 12 patients. Results showed a trend for reduced T₀-OT levels in HD vs. HC, mean ± stardard deviation: 6.5 ± 2.4 vs. 9.9 ± 7.2 pg/mL, without reaching statistical significance. At T₀, patients showed significantly lower performances than controls at the "Faux-Pas" and "Strange Stories" tests (p < 0.05; p < 0.01); a reduced perception of visual emotions (p < 0.01) and verbal stimuli (p < 0.01) was also reported, involving anger, fear, and sadness (p < 0.05; p < 0.01). Additionally, in the HD population, OT concentrations positively correlated with T1-performances at Neutral\Faux-Pas test (p < 0.05), whereas the cognitive Montreal Cognitive Assessment (MoCA) and Mini Mental State Examination (MMSE) scores positively correlated with psychosocial perception at the "Strange Stories" and Karolinska Directed Emotional Faces (KDEF) tests (p < 0.05). This study, despite its limitations, supports correlations between OT and HD social cognition, suggesting a possible therapeutic use of this hormone. More subjects and additional body tissues/fluids, such as cerebrospinal fluid, should be investigated to confirm this hypothesis.

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.

The Alteration of Emotion Regulation Precedes the Deficits in Interval Timing in the BACHD Rat Model for Huntington Disease

Huntington disease (HD) is an autosomal dominantly inherited, progressive neurodegenerative disorder which is accompanied by executive dysfunctions and emotional alteration. The aim of the present study was to assess the impact of emotion/stress on on-going highly demanding cognitive tasks, i.e., temporal processing, as a function of age in BACHD rats (a “full length” model of HD). Middle-aged (4–6 months) and old (10–12 months) rats were first trained on a 2 vs. 8-s temporal discrimination task, and then exposed to a series of bisection tests under normal and stressful (10 mild unpredictable foot-shocks) conditions. The animals were then trained on a peak interval task, in which reinforced fixed-interval (FI) 30-s trials were randomly intermixed with non-reinforced probe trials. After training, the effect of stress upon time perception was again assessed. Sensitivity to foot-shocks was also assessed independently. The results show effects of both age and genotype, with largely greater effects in old BACHD animals. The older BACHD animals had impaired learning in both tasks, but reached equivalent levels of performance as WT animals at the end of training in the temporal discrimination task, while remaining impaired in the peak interval task. Whereas sensitivity to foot-shock did not differ between BACHD and WT rats, delivery of foot-shocks during the test sessions had a disruptive impact on temporal behavior in WT animals, an effect which increased with age. In contrast, BACHD rats, independent of age, did not show any significant disruption under stress. In conclusion, BACHD rats showed a disruption in temporal learning in late symptomatic animals. Age-related modification in stress-induced impairment of temporal control of behavior was also observed, an effect which was greatly reduced in BACHD animals, thus confirming previous results suggesting reduced emotional reactivity in HD animals. The results suggest a staggered onset in cognitive and emotional alterations in HD, with emotional alteration being the earliest, possibly related to different time courses of degeneration in cortico-striatal and amygdala circuits.

The level of cognitive function and recognition of emotions in older adults

Background

The association between cognitive decline and the ability to recognise emotions in interpersonal communication is not well understood. We aimed to investigate the association between cognitive function and the ability to recognise emotions in other people’s facial expressions across the full continuum of cognitive capacity.

Methods

Cross-sectional analysis of 4039 participants (3016 men, 1023 women aged 59 to 82 years) in the Whitehall II study. Cognitive function was assessed using a 30-item Mini-Mental State Examination (MMSE), further classified into 8 groups: 30, 29, 28, 27, 26, 25, 24, and <24 (possible dementia) MMSE points. The Facial Expression Recognition Task (FERT) was used to examine recognition of anger, fear, disgust, sadness, and happiness.

Results

The multivariable adjusted difference in the percentage of accurate recognition between the highest and lowest MMSE group was 14.9 (95%CI, 11.1–18.7) for anger, 15.5 (11.9–19.2) for fear, 18.5 (15.2–21.8) for disgust, 11.6 (7.3–16.0) for sadness, and 6.3 (3.1–9.4) for happiness. However, recognition of several emotions was reduced already after 1 to 2-point reduction in MMSE and with further points down in MMSE, the recognition worsened at an accelerated rate.

Conclusions

The ability to recognize emotion in facial expressions is affected at an early stage of cognitive impairment and might decline at an accelerated rate with the deterioration of cognitive function. Accurate recognition of happiness seems to be less affected by a severe decline in cognitive performance than recognition of negatively valued emotions.

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.

Abnormal Visual Scanning of Emotionally Evocative Natural Scenes in Huntington's Disease

Huntington's disease (HD) is a neurodegenerative movement disorder associated with deficits in the processing of emotional stimuli, including alterations in the self-reported subjective experience of emotion when presented with pictures of emotional scenes. The aim of this study was to determine whether individuals with HD, compared to unaffected controls, display abnormal visual scanning of emotionally evocative natural scenes. Using eye-tracking, we recorded eye-movements of 25 HD participants (advanced pre-symptomatic and early symptomatic) and 25 age-matched unaffected control participants during a picture viewing task. Participants viewed pictures of natural scenes associated with different emotions: anger, fear, disgust, happiness, or neutral, and evaluated those pictures on a valence rating scale. Individuals with HD displayed abnormal visual scanning patterns, but did not differ from controls with respect to their valence ratings. Specifically, compared to controls, HD participants spent less time fixating on the pictures and made longer scan paths. This finding highlights the importance of taking visual scanning behavior into account when investigating emotion processing in HD. The visual scanning patterns displayed by HD participants could reflect a heightened, but possibly unfocussed, search for information, and might be linked to attentional deficits or to altered subjective emotional experiences in HD. Another possibility is that HD participants may have found it more difficult than controls to evaluate the emotional valence of the scenes, and the heightened search for information was employed as a compensatory strategy.