Disgust and happiness recognition correlate with anteroventral insula and amygdala volume respectively in preclinical Huntington's disease

Dissociating emotional and cognitive empathy in pre-clinical and clinical Huntington's disease

Huntington's disease (HD) is centrally characterized by motor, neurocognitive and psychiatric symptoms, but impaired emotional decoding abilities have also been reported. However, more complex affective abilities are still to be explored, and particularly empathy, which is essential for social relations and is impaired in various psychiatric conditions. This study evaluates empathic abilities and social skills in pre-clinical and clinical HD, and explores the distinction between two empathy sub-components (emotional-cognitive). Thirty-six HD patients (17 pre-clinical) and 36 matched controls filled in the Empathy Quotient Scale, while controlling for psychopathological comorbidities. At the clinical stage of HD, no global empathy impairment was observed but rather a specific deficit for the cognitive sub-component, while emotional empathy was preserved. A deficit was also observed for social skills. Pre-clinical HD was not associated with any empathy deficit. Emotional deficits in clinical HD are thus not limited to basic emotion decoding but extend towards complex interpersonal abilities. The dissociation between impaired cognitive and preserved emotional empathy in clinical HD reinforces the proposal that empathy subtypes are sustained by distinct processes. Finally, these results underline the extent of distinct affective and social impairments in HD and the need to grasp them in clinical contexts.

Specific disgust processing in the left insula: New evidence from direct electrical stimulation

Neuropsychological and neuroimaging studies yielded controversial results concerning the specific role of the insula in recognizing the facial expression of disgust. To verify whether the insula has a selective role in facial disgust processing, emotion recognition was studied in thirteen patients during intraoperative stimulation of the insula in awake surgery performed for removal of a glioma close to this structure. Direct electrical stimulation of the left insula produced a general decrease in emotion recognition but only in the case of disgust there was a statistically significant detrimental effect (p=0.004). Happiness and anger were the best and the worst recognized emotion, respectively. The worst baseline performance with anger and, partly, fear could be explained with the involvement of the left temporal regions, striatum, and the connection between the striatum and the frontal lobe, as suggested in previous studies. Therefore, upon these intra-operative evidences, we argue for a selective role of the left insula in disgust recognition, although a (non significant) decrease in the recognition of other negative emotions was found. However, additional networks can develop, as demonstrated by the fact that disgust recognition was not impaired after surgery even in patients with insular resection in the current as in previous studies.

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.

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.

Obsessive-compulsive disorder--A question of conscience? An fMRI study of behavioural and neurofunctional correlates of shame and guilt

Shame and guilt can be described as 'self-conscious emotions' and are an essential part of the psychopathology in obsessive-compulsive disorder (OCD). Our primary aim was to explore whether individuals with OCD are processing shame and guilt differently from healthy individuals (N = 20 in both groups; 50% female; age: 20-40 years) on the behavioural and neurobiological level. For the experimental task, participants were scanned with functional magnetic resonance tomography (functional magnetic resonance imaging, 3 T) while imagining neutral, shame inducing and guilt inducing scenarios. In addition to clinical questionnaires, participants were asked to complete questionnaires measuring shame and guilt. The functional data indicate an increased activity in OCD patients in the shame condition in the limbic, temporal and sub-lobar (hypothalamus) areas, in the guilt condition inter alia in frontal, limbic and temporal areas. In summary we found activity in OCD patients in neural networks which are responsible for stimulus filtering, emotion regulation, impulse control and memory. The results from our study may contribute to a better understanding of the origins and maintenance of OCD in association with the pathological processing of shame and guilt on different functional levels.

Emotion recognition in frontotemporal dementia and Alzheimer's disease: A new film-based assessment

Deficits in recognizing others' emotions are reported in many psychiatric and neurological disorders, including autism, schizophrenia, behavioral variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD). Most previous emotion recognition studies have required participants to identify emotional expressions in photographs. This type of assessment differs from real-world emotion recognition in important ways: Images are static rather than dynamic, include only 1 modality of emotional information (i.e., visual information), and are presented absent a social context. Additionally, existing emotion recognition batteries typically include multiple negative emotions, but only 1 positive emotion (i.e., happiness) and no self-conscious emotions (e.g., embarrassment). We present initial results using a new task for assessing emotion recognition that was developed to address these limitations. In this task, respondents view a series of short film clips and are asked to identify the main characters' emotions. The task assesses multiple negative, positive, and self-conscious emotions based on information that is multimodal, dynamic, and socially embedded. We evaluate this approach in a sample of patients with bvFTD, AD, and normal controls. Results indicate that patients with bvFTD have emotion recognition deficits in all 3 categories of emotion compared to the other groups. These deficits were especially pronounced for negative and self-conscious emotions. Emotion recognition in this sample of patients with AD was indistinguishable from controls. These findings underscore the utility of this approach to assessing emotion recognition and suggest that previous findings that recognition of positive emotion was preserved in dementia patients may have resulted from the limited sampling of positive emotion in traditional tests.

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.

The Brain Basis of Positive and Negative Affect: Evidence from a Meta-Analysis of the Human Neuroimaging Literature

The ability to experience pleasant or unpleasant feelings or to represent objects as "positive" or "negative" is known as representing hedonic "valence." Although scientists overwhelmingly agree that valence is a basic psychological phenomenon, debate continues about how to best conceptualize it scientifically. We used a meta-analysis of 397 functional magnetic resonance imaging (fMRI) and positron emission tomography studies (containing 914 experimental contrasts and 6827 participants) to test 3 competing hypotheses about the brain basis of valence: the bipolarity hypothesis that positive and negative affect are supported by a brain system that monotonically increases and/or decreases along the valence dimension, the bivalent hypothesis that positive and negative affect are supported by independent brain systems, and the affective workspace hypothesis that positive and negative affect are supported by a flexible set of valence-general regions. We found little evidence for the bipolar or bivalent hypotheses. Findings instead supported the hypothesis that, at the level of brain activity measurable by fMRI, valence is flexibly implemented across instances by a set of valence-general limbic and paralimbic brain regions.

Is Dysregulation of the HPA-Axis a Core Pathophysiology Mediating Co-Morbid Depression in Neurodegenerative Diseases?

There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson's disease (PD) and Huntington's disease (HD). These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA)-axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioral deficits and/or mood disorders. Dysregulation of the HPA-axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, antidepressant drugs, such as the selective serotonin reuptake inhibitors have been shown to alter HPA-axis activity. In this review, we will summarize the current state of knowledge regarding HPA-axis pathology in Alzheimer's, PD and HD, differentiating between prodromal and later stages of disease progression when evidence is available. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the preclinical evidence to better inform prospective, intervention studies.

Taste and olfactory status in a gourmand with a right amygdala lesion

In a patient with a lesion of the right amygdala and temporal pole who had the characteristics of the gourmand syndrome, sensory and hedonic testing was performed to examine the processing of taste, olfactory, and some emotional stimuli. The gourmand syndrome describes a preoccupation with food and a preference for fine eating and is associated with right anterior lesions. It was found that the taste thresholds for sweet, salt, bitter, and sour were normal; that the patient did not dislike the taste of salt (NaCl) at low and moderate concentrations as much as age-matched controls; that this also occurred for monosodium glutamate (MSG); that there were some olfactory differences from normal controls; and that there was a marked reduction in the ability to detect face expressions of disgust.

Cerebellar contribution to anger recognition deficits in Huntington's disease

Although there is increasing evidence that cerebellar loss of grey matter volume (GMV) is associated with affective deficits, this has not been tested for patients suffering from Huntington's disease (HD), who show a pronounced impairment in the recognition of anger. We assessed GMV in 18 symptomatic HD patients and 18 healthy controls using voxel-based morphometry. The GMV of cerebellar subregions was correlated with participants' intensity and accuracy ratings for facial expressions of basic emotions from the Karolinska Directed Emotional Faces (Lundqvist et al. 1998). The patients gave lower and less accurate anger ratings for angry faces than controls. This anger recognition deficit was correlated with atrophy of selected hemispheric and vermal regions of the cerebellum. Furthermore, cerebellar volume reductions of the HD patients were associated with longer disease duration and greater functional impairment. The data imply that anger recognition deficits could potentially serve as indicators of disease onset and progression in HD. Furthermore, the patients might profit from specific affect trainings.

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.

Discrete Neural Correlates for the Recognition of Negative Emotions: Insights from Frontotemporal Dementia

Patients with frontotemporal dementia have pervasive changes in emotion recognition and social cognition, yet the neural changes underlying these emotion processing deficits remain unclear. The multimodal system model of emotion proposes that basic emotions are dependent on distinct brain regions, which undergo significant pathological changes in frontotemporal dementia. As such, this syndrome may provide important insight into the impact of neural network degeneration upon the innate ability to recognise emotions. This study used voxel-based morphometry to identify discrete neural correlates involved in the recognition of basic emotions (anger, disgust, fear, sadness, surprise and happiness) in frontotemporal dementia. Forty frontotemporal dementia patients (18 behavioural-variant, 11 semantic dementia, 11 progressive nonfluent aphasia) and 27 healthy controls were tested on two facial emotion recognition tasks: The Ekman 60 and Ekman Caricatures. Although each frontotemporal dementia group showed impaired recognition of negative emotions, distinct associations between emotion-specific task performance and changes in grey matter intensity emerged. Fear recognition was associated with the right amygdala; disgust recognition with the left insula; anger recognition with the left middle and superior temporal gyrus; and sadness recognition with the left subcallosal cingulate, indicating that discrete neural substrates are necessary for emotion recognition in frontotemporal dementia. The erosion of emotion-specific neural networks in neurodegenerative disorders may produce distinct profiles of performance that are relevant to understanding the neurobiological basis of emotion processing.

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.

Structural MRI in Huntington's disease and recommendations for its potential use in clinical trials

Huntington's disease (HD) results in progressive impairment of motor and cognitive function and neuropsychiatric disturbance. There are no disease-modifying treatments available, but HD research is entering a critical phase where promising disease-specific therapies are on the horizon. Thus, a pressing need exists for biomarkers capable of monitoring progression and ultimately determining drug efficacy. Neuroimaging provides a powerful tool for assessing disease progression. However, in order to be accepted as biomarkers for clinical trials, imaging measures must be reproducible, robust to scanner differences, sensitive to disease-related change and demonstrate a relationship to clinically meaningful measures. We provide a review of the current structural imaging literature in HD and highlight inconsistencies between studies. We make recommendations for the standardisation of reporting for future studies, such as appropriate cohort characterisation and documentation of methodologies to facilitate comparisons and inform trial design. We also argue for an intensified effort to consider issues highlighted here so that we have the best chance of assessing the efficacy of the therapeutic benefit in forestalling this devastating disease.

Affective neuronal selection: the nature of the primordial emotion systems

Based on studies in affective neuroscience and evolutionary psychiatry, a tentative new proposal is made here as to the nature and identification of primordial emotional systems. Our model stresses phylogenetic origins of emotional systems, which we believe is necessary for a full understanding of the functions of emotions and additionally suggests that emotional organizing systems play a role in sculpting the brain during ontogeny. Nascent emotional systems thus affect cognitive development. A second proposal concerns two additions to the affective systems identified by Panksepp. We suggest there is substantial evidence for a primary emotional organizing program dealing with power, rank, dominance, and subordination which instantiates competitive and territorial behavior and is an evolutionary contributor to self-esteem in humans. A program underlying disgust reactions which originally functioned in ancient vertebrates to protect against infection and toxins is also suggested.

Brain structure abnormalities in adolescent girls with conduct disorder

BACKGROUND

Conduct disorder (CD) in female adolescents is associated with a range of negative outcomes, including teenage pregnancy and antisocial personality disorder. Although recent studies have documented changes in brain structure and function in male adolescents with CD, there have been no neuroimaging studies of female adolescents with CD. Our primary objective was to investigate whether female adolescents with CD show changes in grey matter volume. Our secondary aim was to assess for sex differences in the relationship between CD and brain structure.

METHODS

Female adolescents with CD (n = 22) and healthy control participants matched in age, performance IQ and handedness (n = 20) underwent structural magnetic resonance imaging. Group comparisons of grey matter volume were performed using voxel-based morphometry. We also tested for sex differences using archive data obtained from male CD and control participants.

RESULTS

Female adolescents with CD showed reduced bilateral anterior insula and right striatal grey matter volumes compared with healthy controls. Aggressive CD symptoms were negatively correlated with right dorsolateral prefrontal cortex volume, whereas callous-unemotional traits were positively correlated with bilateral orbitofrontal cortex volume. The sex differences analyses revealed a main effect of diagnosis on right amygdala volume (reflecting reduced amygdala volume in the combined CD group relative to controls) and sex-by-diagnosis interactions in bilateral anterior insula.

CONCLUSIONS

We observed structural abnormalities in brain regions involved in emotion processing, reward and empathy in female adolescents with CD, which broadly overlap with those reported in previous studies of CD in male adolescents.

Evolution of brain gray matter loss in Huntington's disease: a meta-analysis

BACKGROUND

Huntington's disease is characterized by neuronal loss throughout the disease course. Voxel-based morphometry studies have reported reductions in gray matter concentration (GMC) in many brain regions in patients with Huntington. The description of the time course of gray matter loss may help to identify some evolution markers. Here, we conducted a meta-analysis of voxel-based morphometry studies of Huntington's disease to describe the evolution of brain gray matter loss.

METHODS

A systematic search led to the inclusion of 11 articles on Huntington's disease (297 patients and 205 controls). We extracted data from patients with preclinical Huntington, patients with clinical Huntington, and controls. Finally, anatomical likelihood estimation analyses were conducted to identify GMC changes between preclinical patients and controls, between clinical patients and controls, and between preclinical and clinical patients.

RESULTS

Preclinical patients exhibited gray matter loss in the left basal ganglia and the prefrontal cortex. Clinical patients had bilateral gray matter loss in the basal ganglia, the prefrontal cortex, and the insula. The left striatum was smaller in clinical patients than in preclinical patients.

CONCLUSIONS

Neurodegenerative processes associated with Huntington's disease, as assessed by GMC reduction, begin in the left hemisphere and extend to the contralateral hemisphere throughout the inexorable course of the disease. Changes in gray matter, especially the volumetric side ratio of the striatum, could represent a relevant biomarker for characterizing the different progression stages of the disease.

Consistent neurodegeneration and its association with clinical progression in Huntington's disease: a coordinate-based meta-analysis

BACKGROUND

The neuropathological hallmark of Huntington's disease (HD) is progressive striatal loss starting several years prior to clinical onset. In the past decade, whole-brain magnetic resonance imaging (MRI) studies have provided accumulating evidence for widely distributed cortical and subcortical atrophy in the early course of the disease.

OBJECTIVE

In order to synthesize current morphometric MRI findings and to investigate the impact of clinical and genetic features on structural changes, we performed a coordinate-based meta-analysis of voxel-based morphometry (VBM) studies in HD.

METHODS

Twenty HD samples derived from 17 studies were integrated in the analysis comparing a total of 685 HD mutation carriers [345 presymptomatic (pre-HD) and 340 symptomatic (symp-HD) subjects] and 507 controls. Convergent findings across studies were delineated using the anatomical likelihood estimation approach. Effects of genetic and clinical parameters on the likelihood of observing VBM findings were calculated by means of correlation analyses.

RESULTS

Pre-HD studies featured convergent evidence for neurodegeneration in the basal ganglia, amygdala, thalamus, insula and occipital regions. In symp-HD, cerebral atrophy was more pronounced and spread to cortical regions (i.e., inferior frontal, premotor, sensorimotor, midcingulate, frontoparietal and temporoparietal cortices). Higher cytosine-adenosine-guanosine repeats were associated with striatal degeneration, while parameters of disease progression and motor impairment additionally correlated with cortical atrophy, especially in sensorimotor areas.

CONCLUSION

This first quantitative meta-analysis in HD demonstrates the extent of striatal atrophy and further consistent extrastriatal degeneration before clinical conversion. Sensorimotor areas seem to be core regions affected in symp-HD and, along with widespread cortical atrophy, may account for the clinical heterogeneity in HD.

Functional neuroimaging in specific phobia

Specific phobias (SPs) are common, with lifetime prevalence estimates of 10%. Our current understanding of their pathophysiology owes much to neuroimaging studies, which enabled us to construct increasingly efficient models of the underlying neurocircuitry. We provide an updated, comprehensive review and analyze the relevant literature of functional neuroimaging studies in specific phobias. Findings are presented according to the functional neuroanatomy of patients with SPs. We performed a careful search of the major medical and psychological databases by crossing SP with each neuroimaging technique. Functional neuroimaging, mostly using symptom provocation paradigms, showed abnormal activations in brain areas involved in emotional perception and early amplification, mainly the amygdala, anterior cingulate cortex, thalamus, and insula. The insula, thalamus and other limbic/paralimbic structures are particularly involved in SPs with prominent autonomic arousal. Emotional modulation is also impaired after exposure to phobic stimuli, with abnormal activations reported for the prefrontal, orbitofrontal and visual cortices. Other cortices and the cerebellum also appear to be involved in the pathophysiology of this disorder. Functional neuroimaging identified neural substrates that differentiate SPs from other anxiety disorders and separate SP subtypes from one another; the results support current Diagnostic and Statistical Manual of Mental Disorders, 4th edition-Text Revision (DSM-IV-TR) diagnostic subtyping of SPs. Functional neuroimaging shows promise as a means of identifying treatment-response predictors. Improvement in these techniques may help in clarifying the neurocircuitry underlying SP, for both research and clinical-therapeutic purposes.

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.

The brain basis of emotion: a meta-analytic review

Researchers have wondered how the brain creates emotions since the early days of psychological science. With a surge of studies in affective neuroscience in recent decades, scientists are poised to answer this question. In this target article, we present a meta-analytic summary of the neuroimaging literature on human emotion. We compare the locationist approach (i.e., the hypothesis that discrete emotion categories consistently and specifically correspond to distinct brain regions) with the psychological constructionist approach (i.e., the hypothesis that discrete emotion categories are constructed of more general brain networks not specific to those categories) to better understand the brain basis of emotion. We review both locationist and psychological constructionist hypotheses of brain-emotion correspondence and report meta-analytic findings bearing on these hypotheses. Overall, we found little evidence that discrete emotion categories can be consistently and specifically localized to distinct brain regions. Instead, we found evidence that is consistent with a psychological constructionist approach to the mind: A set of interacting brain regions commonly involved in basic psychological operations of both an emotional and non-emotional nature are active during emotion experience and perception across a range of discrete emotion categories.

Social cognitive deficits and their neural correlates in progressive supranuclear palsy

Although progressive supranuclear palsy is defined by its akinetic rigidity, vertical supranuclear gaze palsy and falls, cognitive impairments are an important determinant of patients’ and carers’ quality of life. Here, we investigate whether there is a broad deficit of modality-independent social cognition in progressive supranuclear palsy and explore the neural correlates for these. We recruited 23 patients with progressive supranuclear palsy (using clinical diagnostic criteria, nine with subsequent pathological confirmation) and 22 age- and education-matched controls. Participants performed an auditory (voice) emotion recognition test, and a visual and auditory theory of mind test. Twenty-two patients and 20 controls underwent structural magnetic resonance imaging to analyse neural correlates of social cognition deficits using voxel-based morphometry. Patients were impaired on the voice emotion recognition and theory of mind tests but not auditory and visual control conditions. Grey matter atrophy in patients correlated with both voice emotion recognition and theory of mind deficits in the right inferior frontal gyrus, a region associated with prosodic auditory emotion recognition. Theory of mind deficits also correlated with atrophy of the anterior rostral medial frontal cortex, a region associated with theory of mind in health. We conclude that patients with progressive supranuclear palsy have a multimodal deficit in social cognition. This deficit is due, in part, to progressive atrophy in a network of frontal cortical regions linked to the integration of socially relevant stimuli and interpretation of their social meaning. This impairment of social cognition is important to consider for those managing and caring for patients with progressive supranuclear palsy.

Disturbance of emotion processing in frontotemporal dementia: a synthesis of cognitive and neuroimaging findings

Accurate processing of emotional information is a critical component of appropriate social interactions and interpersonal relationships. Disturbance of emotion processing is present in frontotemporal dementia (FTD) and is a clinical feature in two of the three subtypes: behavioural-variant FTD and semantic dementia. Emotion processing in progressive nonfluent aphasia, the third FTD subtype, is thought to be mostly preserved, although current evidence is scant. This paper reviews the literature on emotion recognition, reactivity and expression in FTD subtypes, although most studies focus on emotion recognition. The relationship between patterns of emotion processing deficits and patterns of neural atrophy are considered, by integrating evidence from recent neuroimaging studies. The review findings are discussed in the context of three contemporary theories of emotion processing: the limbic system model, the right hemisphere model and a multimodal system of emotion. Results across subtypes of FTD are most consistent with the multimodal system model, and support the presence of somewhat dissociable neural correlates for basic emotions, with strongest evidence for the emotions anger and sadness. Poor emotion processing is evident in all three subtypes, although deficits are more widespread than what would be predicted based on studies in healthy cohorts. Studies that include behavioural and imaging data are limited. Future investigations combining these approaches will help improve the understanding of the neural network underlying emotion processing. Presently, longitudinal investigations of emotion processing in FTD are lacking, and studies investigating emotion processing over time are critical to understand the clinical manifestations of disease progression in FTD.

Brain-immune interactions and the neural basis of disease-avoidant ingestive behaviour

Neuro-immune interactions are widely manifested in animal physiology. Since immunity competes for energy with other physiological functions, it is subject to a circadian trade-off between other energy-demanding processes, such as neural activity, locomotion and thermoregulation. When immunity is challenged, this trade-off is tilted to an adaptive energy protecting and reallocation strategy that is identified as 'sickness behaviour'. We review diverse disease-avoidant behaviours in the context of ingestion, indicating that several adaptive advantages have been acquired by animals (including humans) during phylogenetic evolution and by ontogenetic experiences: (i) preventing waste of energy by reducing appetite and consequently foraging/hunting (illness anorexia), (ii) avoiding unnecessary danger by promoting safe environments (preventing disease encounter by olfactory cues and illness potentiation neophobia), (iii) help fighting against pathogenic threats (hyperthermia/somnolence), and (iv) by associative learning evading specific foods or environments signalling danger (conditioned taste avoidance/aversion) and/or at the same time preparing the body to counteract by anticipatory immune responses (conditioning immunomodulation). The neurobiology behind disease-avoidant ingestive behaviours is reviewed with special emphasis on the body energy balance (intake versus expenditure) and an evolutionary psychology perspective.

Structural neuroanatomy of face processing in frontotemporal lobar degeneration

Impairments of face processing occur frequently in frontotemporal lobar degeneration (FTLD) but the neuroanatomical basis for these deficits has seldom been studied systematically. Here a prospective voxel based morphometry study is described addressing the neuroanatomy of two key dimensions of face processing--face identification and facial emotion recognition--in a single cohort of 32 patients with FTLD (19 with frontal variant and 13 with temporal variant FTLD). For the FTLD group as a whole, face identification was positively associated with grey matter in the right anterior fusiform gyrus while recognition of angry expressions was positively associated with grey matter in the bilateral insula cortex. FTLD provides a perspective on the neuroanatomy of face processing that is complementary to focal lesion and normal functional imaging work.

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.

Acquired self-control of insula cortex modulates emotion recognition and brain network connectivity in schizophrenia

Real-time functional magnetic resonance imaging (rtfMRI) is a novel technique that has allowed subjects to achieve self-regulation of circumscribed brain regions. Despite its anticipated therapeutic benefits, there is no report on successful application of this technique in psychiatric populations. The objectives of the present study were to train schizophrenia patients to achieve volitional control of bilateral anterior insula cortex on multiple days, and to explore the effect of learned self-regulation on face emotion recognition (an extensively studied deficit in schizophrenia) and on brain network connectivity. Nine patients with schizophrenia were trained to regulate the hemodynamic response in bilateral anterior insula with contingent rtfMRI neurofeedback, through a 2-weeks training. At the end of the training stage, patients performed a face emotion recognition task to explore behavioral effects of learned self-regulation. A learning effect in self-regulation was found for bilateral anterior insula, which persisted through the training. Following successful self-regulation, patients recognized disgust faces more accurately and happy faces less accurately. Improvements in disgust recognition were correlated with levels of self-activation of right insula. RtfMRI training led to an increase in the number of the incoming and outgoing effective connections of the anterior insula. This study shows for the first time that patients with schizophrenia can learn volitional brain regulation by rtfMRI feedback training leading to changes in the perception of emotions and modulations of the brain network connectivity. These findings open the door for further studies of rtfMRI in severely ill psychiatric populations, and possible therapeutic applications.

The insular cortex and the neuroanatomy of major depression

BACKGROUND

The neuroanatomical substrate underlying Major Depressive Disorder (MDD) is incompletely understood. Recent reports have implicated the insular cortex.

METHODS

Two cohorts of participants with MDD were tested. In the first MDD cohort, we used standardised facial expression recognition tasks. In the second cohort, we focused on facial disgust recognition, a function associated with the insular cortex. T1 weighted MR imaging was used in the second cohort to test the hypothesis of abnormal insular volume being associated with impaired disgust recognition.

RESULTS

Disgust recognition was particularly impaired in both cohorts. In the second cohort, the magnitude of the disgust recognition deficit correlated with reduced insula grey matter volume. Exploring the idea of insula involvement in MDD further, we identified the insular cortex and the anterior cingulate cortex as key neural correlates of core symptoms, in that scores of 3 clinical scales (the Beck Depression Inventory, the Hamilton Depression Rating Scale, and the Snaith-Hamilton Pleasure Scale) correlated with grey matter volume in these structures.

LIMITATIONS

MDD participants were clinically representative of specialist and academic psychiatric practice in the UK and presented with robust primary diagnoses; we did not exclude common co-morbidities such as anxiety and personality disorders.

CONCLUSIONS

We propose that cognitive and emotional functions assumed to be associated with the insula are adversely affected in patients with MDD and that this may, therefore, represent the substrate for some core clinical features of MDD. Further exploration of the involvement of the insular cortex in MDD is warranted.

Distinct pathways of neural coupling for different basic emotions

Emotions are complex events recruiting distributed cortical and subcortical cerebral structures, where the functional integration dynamics within the involved neural circuits in relation to the nature of the different emotions are still unknown. Using fMRI, we measured the neural responses elicited by films representing basic emotions (fear, disgust, sadness, happiness). The amygdala and the associative cortex were conjointly activated by all basic emotions. Furthermore, distinct arrays of cortical and subcortical brain regions were additionally activated by each emotion, with the exception of sadness. Such findings informed the definition of three effective connectivity models, testing for the functional integration of visual cortex and amygdala, as regions processing all emotions, with domain-specific regions, namely: i) for fear, the frontoparietal system involved in preparing adaptive motor responses; ii) for disgust, the somatosensory system, reflecting protective responses against contaminating stimuli; iii) for happiness: medial prefrontal and temporoparietal cortices involved in understanding joyful interactions. Consistently with these domain-specific models, the results of the effective connectivity analysis indicate that the amygdala is involved in distinct functional integration effects with cortical networks processing sensorimotor, somatosensory, or cognitive aspects of basic emotions. The resulting effective connectivity networks may serve to regulate motor and cognitive behavior based on the quality of the induced emotional experience.

Personality influences the neural responses to viewing facial expressions of emotion

Cognitive research has long been aware of the relationship between individual differences in personality and performance on behavioural tasks. However, within the field of cognitive neuroscience, the way in which such differences manifest at a neural level has received relatively little attention. We review recent research addressing the relationship between personality traits and the neural response to viewing facial signals of emotion. In one section, we discuss work demonstrating the relationship between anxiety and the amygdala response to facial signals of threat. A second section considers research showing that individual differences in reward drive (behavioural activation system), a trait linked to aggression, influence the neural responsivity and connectivity between brain regions implicated in aggression when viewing facial signals of anger. Finally, we address recent criticisms of the correlational approach to fMRI analyses and conclude that when used appropriately, analyses examining the relationship between personality and brain activity provide a useful tool for understanding the neural basis of facial expression processing and emotion processing in general.

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.

Cross-emotion facial expression aftereffects

Increasing evidence suggests that the visual representations of different emotional facial expressions overlap. Here we used an adaptation paradigm to investigate overlap of anger, disgust and fear expressions. In Experiment 1, participants categorized faces morphed from neutral to anger or neutral to disgust after adaptation to expressions of anger, disgust, and fear. Adaptation to expressions of both anger and disgust was found to bias perception of anger expressions away from anger. For disgust expressions, adaptation to disgust biased perception away from disgust, whereas fear adaptation biased perception towards disgust. Adaptation to anger had no measurable effect. In Experiment 2, covering the mouth-region of the disgust adaptation face was found to severely diminish the effect of disgust adaptation on perception of anger targets whereas covering the nose- or eye-region had no effect. In Experiment 3, adaptation to anger had a substantial effect on perception of anger targets when the mouth-region of the anger face was covered; indicating that the results of Experiment 2 are not an artefact of the stimuli and procedures used. These results indicate that the visual representations of anger, disgust and fear expressions overlap to a considerable degree. Furthermore, the nature of this overlap appears related to the communicative functions of these expressions.

Genetics and neuropathology of Huntington's disease

Huntington's disease (HD) is an autosomal dominant progressive neurodegenerative disorder that prominently affects the basal ganglia, leading to affective, cognitive, behavioral and motor decline. The basis of HD is a CAG repeat expansion to >35 CAG in a gene that codes for a ubiquitous protein known as huntingtin, resulting in an expanded N-terminal polyglutamine tract. The size of the expansion is correlated with disease severity, with increasing CAG accelerating the age of onset. A variety of possibilities have been proposed as to the mechanism by which the mutation causes preferential injury to the basal ganglia. The present chapter provides a basic overview of the genetics and pathology of HD.

Three systems of insular functional connectivity identified with cluster analysis

Despite much research on the function of the insular cortex, few studies have investigated functional subdivisions of the insula in humans. The present study used resting-state functional connectivity magnetic resonance imaging (MRI) to parcellate the human insular lobe based on clustering of functional connectivity patterns. Connectivity maps were computed for each voxel in the insula based on resting-state functional MRI (fMRI) data and segregated using cluster analysis. We identified 3 insular subregions with distinct patterns of connectivity: a posterior region, functionally connected with primary and secondary somatomotor cortices; a dorsal anterior to middle region, connected with dorsal anterior cingulate cortex, along with other regions of a previously described control network; and a ventral anterior region, primarily connected with pregenual anterior cingulate cortex. Applying these regions to a separate task data set, we found that dorsal and ventral anterior insula responded selectively to disgusting images, while posterior insula did not. These results demonstrate that clustering of connectivity patterns can be used to subdivide cerebral cortex into anatomically and functionally meaningful subregions; the insular regions identified here should be useful in future investigations on the function of the insula.

The embodiment of emotional feelings in the brain

Central to Walter Cannon's challenge to peripheral theories of emotion was that bodily arousal responses are too undifferentiated to account for the wealth of emotional feelings. Despite considerable evidence to the contrary, this remains widely accepted and for nearly a century has left the issue of whether visceral afferent signals are essential for emotional experience unresolved. Here we combine functional magnetic resonance imaging and multiorgan physiological recording to dissect experience of two distinct disgust forms and their relationship to peripheral and central physiological activity. We show that experience of core and body-boundary-violation disgust are dissociable in both peripheral autonomic and central neural responses and also that emotional experience specific to anterior insular activity encodes these different underlying patterns of peripheral physiological responses. These findings demonstrate that organ-specific physiological responses differentiate emotional feeling states and support the hypothesis that central representations of organism physiological homeostasis constitute a critical aspect of the neural basis of feelings.

Emotions in action through the looking glass

The paper aims at highlighting how our primary understanding of others' actions is rooted in the mirror mechanism. To this end, the anatomical architecture of the mirror neuron system for action will be outlined as well as its role in grasping goals and intentions in others' motor behaviour. One further step through the looking glass of social cognition will be referring to the ubiquitous emotional colouring of actions and considering its links with the motor domain. This will allow a clearer perspective on the mechanism underlying our abilities for emotional understanding and on cases in which these abilities are amiss, as in autistic spectrum disorders.

Early changes in the hypothalamic region in prodromal Huntington disease revealed by MRI analysis

Huntington disease (HD) is a fatal neurodegenerative disorder caused by an expanded CAG repeat. Its length can be used to estimate the time of clinical diagnosis, which is defined by overt motor symptoms. Non-motor symptoms begin before motor onset, and involve changes in hypothalamus-regulated functions such as sleep, emotion and metabolism. Therefore we hypothesized that hypothalamic changes occur already prior to the clinical diagnosis. We performed voxel-based morphometry and logistic regression analyses of cross-sectional MR images from 220 HD gene carriers and 75 controls in the Predict-HD study. We show that changes in the hypothalamic region are detectable before clinical diagnosis and that its grey matter contents alone are sufficient to distinguish HD gene carriers from control cases. In conclusion, our study shows, for the first time, that alterations in grey matter contents in the hypothalamic region occur at least a decade before clinical diagnosis in HD using MRI.

The relation between anger and different forms of disgust: implications for emotion recognition impairments in Huntington's disease

Initial reports of emotion recognition in Huntington's disease (HD) found disproportionate impairments in recognising disgust. Not all subsequent studies have found this pattern, and a review of the literature to date shows that marked impairments in recognising anger are also often seen in HD. However, the majority of studies have based their conclusions on a single test of facial expression recognition. In the current study we revisit this issue of emotion recognition in HD to address whether the pattern found on one test of facial expression recognition generalised to another, and to different modalities using tests of emotion recognition from facial expressions, vocal expressions, and short verbal vignettes. The results showed evidence of impairments in recognising anger, fear and disgust across the three domains, with recognition of anger the most severely impaired. Given work identifying different subtypes of disgust that are associated with different facial features, a second study examined the recognition of three disgust expressions that healthy participants reliably associate with unpleasant tastes, unpleasant smells, and a more general elaborated or expanded form of disgust that includes reactions to violations of moral standards. The results showed a disproportionate impairment in recognising faces associated with the expanded form, the subtype most closely aligned with anger. We conclude that the related emotions of disgust and anger associated with social disapproval are frequently impaired in HD and discuss factors that might cause one emotion to show more severe impairments than the other.