Brain activation by disgust-inducing pictures in obsessive-compulsive disorder

Glutamate dynamics and BOLD response during OCD symptom provocation in the lateral occipital cortex: A 7 Tesla fMRI-fMRS study

Obsessive-compulsive disorder (OCD) is linked with dysfunction in frontal-striatal, fronto-limbic, and visual brain regions. Research using proton magnetic resonance spectroscopy (1H-MRS) suggests that altered neurometabolite levels, like glutamate, may contribute to this dysfunction. However, static neurometabolite levels in OCD patients have shown inconsistent results, likely due to previous studies' limited focus on neurometabolite dynamics. We employ functional MRS (fMRS) and functional magnetic resonance imaging (fMRI) to explore these dynamics and brain activation during OCD symptom provocation. We utilized a combined 7-tesla fMRI-fMRS setup to examine task-related BOLD response and glutamate changes in the lateral occipital cortex (LOC) of 30 OCD participants and 34 matched controls during an OCD-specific symptom provocation task. The study examined main effects and between-group differences in brain activation and glutamate levels during the task. A whole sample task-effects analysis on data meeting predefined quality criteria showed significant glutamate increases (n = 41 (22 OCD, 19 controls), mean change: 3.2 %, z = 3.75, p < .001) and task activation (n = 54 (26 OCD, 28 controls), p < .001) in the LOC during OCD blocks compared to neutral blocks. However, no differences in task-induced glutamate dynamics or activation between groups were found, nor a correlation between glutamate levels and task activation. We were able to measure task-induced increases in glutamate and BOLD levels, emphasizing its feasibility for OCD research. The absence of group differences highlights the need for further exploration to discern to what extent neurometabolite dynamics differ between OCD patients and controls. Once established, future studies can use pre-post intervention fMRS-fMRI to probe the effects of therapies modulating glutamate pathways in OCD.

A neurofunctional signature of subjective disgust generalizes to oral distaste and socio-moral contexts

While disgust originates in the hard-wired mammalian distaste response, the conscious experience of disgust in humans strongly depends on subjective appraisal and may even extend to socio-moral contexts. Here, in a series of studies, we combined functional magnetic resonance imaging with machine-learning-based predictive modelling to establish a comprehensive neurobiological model of subjective disgust. The developed neurofunctional signature accurately predicted momentary self-reported subjective disgust across discovery (n = 78) and pre-registered validation (n = 30) cohorts and generalized across core disgust (n = 34 and n = 26), gustatory distaste (n = 30) and socio-moral (unfair offers; n = 43) contexts. Disgust experience was encoded in distributed cortical and subcortical systems, and exhibited distinct and shared neural representations with subjective fear or negative affect in interoceptive-emotional awareness and conscious appraisal systems, while the signatures most accurately predicted the respective target experience. We provide an accurate functional magnetic resonance imaging signature for disgust with a high potential to resolve ongoing evolutionary debates.

A multimodal meta-analysis of regional functional and structural brain abnormalities in obsessive-compulsive disorder

Numerous neuroimaging studies of resting-state functional imaging and voxel-based morphometry (VBM) have revealed abnormalities in specific brain regions in obsessive-compulsive disorder (OCD), but results have been inconsistent. We conducted a whole-brain voxel-wise meta-analysis on resting-state functional imaging and VBM studies that investigated differences of functional activity and gray matter volume (GMV) between patients with OCD and healthy controls (HCs) using seed-based d mapping (SDM) software. A total of 41 independent studies (51 datasets) for resting-state functional imaging and 42 studies (46 datasets) for VBM were included by a systematic literature search. Overall, patients with OCD displayed increased spontaneous functional activity in the bilateral inferior frontal gyrus (IFG) (extending to the bilateral insula) and bilateral medial prefrontal cortex/anterior cingulate cortex (mPFC/ACC), as well as decreased spontaneous functional activity in the bilateral paracentral lobule, bilateral cerebellum, left caudate nucleus, left inferior parietal gyri, and right precuneus cortex. For the VBM meta-analysis, patients with OCD displayed increased GMV in the bilateral thalamus (extending to the bilateral cerebellum), right striatum, and decreased GMV in the bilateral mPFC/ACC and left IFG (extending to the left insula). The conjunction analyses found that the bilateral mPFC/ACC, left IFG (extending to the left insula) showed decreased GMV with increased intrinsic function in OCD patients compared to HCs. This meta-analysis demonstrated that OCD exhibits abnormalities in both function and structure in the bilateral mPFC/ACC, insula, and IFG. A few regions exhibited only functional or only structural abnormalities in OCD, such as the default mode network, striatum, sensorimotor areas, and cerebellum. It may provide useful insights for understanding the underlying pathophysiology of OCD and developing more targeted and efficacious treatment and intervention strategies.

Comparison of Emotional Processing Between Patients with Substance Use Disorder and Those with Dual Diagnosis: Relationship with Severity of Dependence and Use During Treatment

This study analyzed, in a Spanish sample, the differences in emotional processing in patients diagnosed with substance use disorder (SUD) and patients with a dual diagnosis (DD), and tested whether alterations in emotional regulation were related to the severity of dependence and consumption during treatment. A descriptive follow-up study was conducted with 88 adult outpatients (83% men) who were receiving treatment for alcohol and cocaine SUD. Of the sample, 43.2% presented dual diagnosis according to DSM-IV-TR criteria. Emotional processing was assessed with the IAPS, and dependence severity with the SDSS. Consumption was determined with self-reports and toxicological tests. Regression analyses revealed that the DD group had more difficulties in identifying the valence and arousal of the images than patients with SUD. Patients with DD presented more difficulty in identifying images in which valence was manipulated, but not in those in which arousal was manipulated. Cocaine use during treatment was associated with difficulties in identifying unpleasant (U = 734.0; p < .05) and arousing (U = 723.5; p < .05) images. Although these results are preliminary, findings suggest that impaired emotional processing is aggravated in dual patients, although it may be a common transdiagnostic factor in SUD and other comorbid mental disorders. Findings highlight the importance of evaluating emotional regulation to better understand its possible role in the maintenance of substance use.

The Seeking Proxies for Internal States (SPIS) Model of OCD - A Comprehensive Review of Current Findings and Implications for Future Directions

The Seeking Proxies for Internal States (SPIS) model of obsessive-compulsive disorder (OCD) explains symptoms of OCD as stemming from attenuated access to internal states, which is compensated for by using proxies, which are indices of these states that are more discernible or less ambiguous. Internal states in the SPIS model are subjective states that are not accessible to others, encompassing physiological states, motivations, preferences, memories, and emotions. Compensatory proxies in OCD include fixed rules and rituals as well as seeking and relying on external information. In the present review, we outline the SPIS model and describe its basic tenets. We then use the SPIS conceptualization to explain two pivotal OCD-related phenomena - obsessive doubt and compulsive rituals. Next, we provide a detailed overview of current empirical evidence supporting the SPIS in several domains, including physiological states, emotions, sense of understanding, decision-making, and sense of agency. We conclude by discussing possible neural correlates of the difficulty in accessing internal states, focusing on the anterior insular cortex (AIC) and highlighting potential clinical implications of the model to the treatment of OCD.

Neural Correlates of Facial Emotion Recognition Impairment in Blepharospasm: A Functional Magnetic Resonance Imaging Study

Selective impairment in recognizing facial expressions of disgust was reported in patients with focal dystonia several years ago, but the basic neural mechanisms remain largely unexplored. Therefore, we investigated whether dysfunction of the brain network involved in disgust recognition processing was related to this selective impairment in blepharospasm. Facial emotion recognition evaluations and resting-state functional magnetic resonance imaging were performed in 33 blepharospasm patients and 33 healthy controls (HCs). The disgust processing network was constructed, and modularity analyses were performed to identify sub-networks. Regional functional indexes and intra- and inter-functional connections were calculated and compared between the groups. Compared to HCs, blepharospasm patients demonstrated a worse performance in disgust recognition. In addition, functional connections within the sub-network involved in perception processing rather than recognition processing of disgust were significantly decreased in blepharospasm patients compared to HCs. Specifically, decreased functional connections were noted between the left fusiform gyrus (FG) and right middle occipital gyrus (MOG), the left FG and right FG, and the right FG and left MOG. We identified decreased functional activity in these regions, as indicated by a lower amplitude of low-frequency fluctuation in the left MOG, fractional amplitude of low-frequency fluctuation in the right FG, and regional homogeneity in the right FG and left MOG in blepharospasm patients versus HCs. Our results suggest that dysfunctions of the disgust processing network exist in blepharospasm. A deficit in disgust emotion recognition may be attributed to disturbances in the early perception of visual disgust stimuli in blepharospasm patients.

Mice lacking Ptprd exhibit deficits in goal-directed behavior and female-specific impairments in sensorimotor gating

Protein Tyrosine Phosphatase receptor type D (PTPRD) is a member of the protein tyrosine phosphatase family that mediates cell adhesion and synaptic specification. Genetic studies have linked Ptprd to several neuropsychiatric phenotypes, including Restless Leg Syndrome (RLS), opioid abuse disorder, and antipsychotic-induced weight gain. Genome-wide association studies (GWAS) of either pediatric obsessive-compulsive traits, or Obsessive-Compulsive Disorder (OCD), have identified loci near PTPRD as genome-wide significant, or strongly suggestive for this trait. We assessed Ptprd wild-type (WT), heterozygous (HT), and knockout (KO) mice for behavioral dimensions that are altered in OCD, including anxiety and exploration (open field test, dig test), perseverative behavior (splash-induced grooming, spatial d), sensorimotor gating (prepulse inhibition), and home cage goal-directed behavior (nest building). No effect of genotype was observed in any measure of the open field test, dig test, or splash test. However, Ptprd KO mice of both sexes showed impairments in nest building behavior. Finally, female, but not male, Ptprd KO mice showed deficits in prepulse inhibition, an operational measure of sensorimotor gating that is reduced in female, but not male, OCD patients. Our results indicate that constitutive lack of Ptprd may contribute to the development of certain domains that are altered OCD, including goal-directed behavior, and reduced sensorimotor gating specifically in females.

Relationships between interoceptive sensibility and resting-state functional connectivity of the insula in obsessive-compulsive disorder

Patients with obsessive-compulsive disorder (OCD) exhibit abnormality in their subjective perception of internal sensation, a process known as interoceptive sensibility (IS), as well as altered functioning of the insula, a key neural structure for interoception. We investigated the multivariate structure of IS in 77 OCD patients and 53 controls and examined associations of IS with resting-state functional connectivity (FC) of the insula within the OCD group. For each group, principal component analysis was performed on 8 subscales of the Multidimensional Assessment of Interoceptive Awareness assessing putatively "adaptive" and "maladaptive" aspects of IS. Associations between IS components and insula FC in the OCD group were evaluated using seed regions placed in each of 3 subdivisions of the insula (posterior, anterior dorsal, and anterior ventral). Behaviorally, controls showed a 2-component solution broadly categorized into "adaptive" and "maladaptive" IS, while OCD patients exhibited a 3-component solution. The general tendency to notice or be aware of sensation loaded onto an "adaptive" IS component in controls but loaded onto both "adaptive" and "maladaptive" IS components in OCD. Within OCD, insula FC was differentially associated with distinct aspects of IS, identifying network connections that could serve as future targets for the modulation of IS in OCD.

Disorganized functional architecture of amygdala subregional networks in obsessive-compulsive disorder

A precise understanding of amygdala-centered subtle networks may help refine neurocircuitry models of obsessive-compulsive disorder (OCD). We applied connectivity-based parcellation methodology to segment the amygdala based on resting-state fMRI data of 92 medication-free OCD patients without comorbidity and 90 matched healthy controls (HC). The amygdala was parcellated into two subregions corresponding to basolateral amygdala (BLA) and centromedial amygdala (CMA). Amygdala subregional functional connectivity (FC) maps were generated and group differences were evaluated with diagnosis-by-subregion flexible factorial ANOVA. We found significant diagnosis × subregion FC interactions in insula, supplementary motor area (SMA), midcingulate cortex (MCC), superior temporal gyrus (STG) and postcentral gyrus (PCG). In HC, the BLA demonstrated stronger connectivity with above regions compared to CMA, whereas in OCD, the connectivity pattern reversed to stronger CMA connectivity comparing to BLA. Relative to HC, OCD patients exhibited hypoconnectivity between left BLA and left insula, and hyperconnectivity between right CMA and SMA, MCC, insula, STG, and PCG. Moreover, OCD patients showed reduced volume of left BLA and right CMA compared to HC. Our findings characterized disorganized functional architecture of amygdala subregional networks in accordance with structural defects, providing direct evidence regarding the specific role of amygdala subregions in the neurocircuitry models of OCD.

Functional Connectivity within the Frontal–Striatal Network Differentiates Checkers from Washers of Obsessive-Compulsive Disorder

Background: Obsessive-compulsive disorder (OCD) is a psychiatric disorder with high clinical heterogeneity manifested by the presence of obsessions and/or compulsions. The classification of the symptom dimensional subtypes is helpful for further exploration of the pathophysiological mechanisms underlying the clinical heterogeneity of OCD. Washing and checking symptoms are the two major symptom subtypes in OCD, but the neural mechanisms of the different types of symptoms are not yet clearly understood. The purpose of this study was to compare regional and network functional alterations between washing and checking OCD based on resting-state functional magnetic resonance imaging (rs-fMRI). Methods: In total, 90 subjects were included, including 15 patients in the washing group, 30 patients in the checking group, and 45 healthy controls (HCs). Regional homogeneity (ReHo) was used to compare the differences in regional spontaneous neural activity among the three groups, and local indicators were analyzed by receiver operating characteristic (ROC) curves as imaging markers for the prediction of the clinical subtypes of OCD. Furthermore, differently activated local brain areas, as regions of interest (ROIs), were used to explore differences in altered brain functioning between washing and checking OCD symptoms based on a functional connectivity (FC) analysis. Results: Extensive abnormalities in spontaneous brain activity involving frontal, temporal, and occipital regions were observed in the patients compared to the HCs. The differences in local brain functioning between checking and washing OCD were mainly concentrated in the bilateral middle frontal gyrus, right supramarginal gyrus, right angular gyrus, and right inferior occipital gyrus. The ROC curve analysis revealed that the hyperactivation right middle frontal gyrus had a better discriminatory value for checking and washing OCD. Furthermore, the seed-based FC analysis revealed higher FC between the left medial superior frontal gyrus and right caudate nucleus compared to that in the healthy controls. Conclusions: These findings suggest that extensive local differences exist in intrinsic spontaneous activity among the checking group, washing group, and HCs. The neural basis of checking OCD may be related to dysfunction in the frontal–striatal network, which distinguishes OCD from washing OCD.

Abnormal spontaneous neural activity in hippocampal-cortical system of patients with obsessive-compulsive disorder and its potential for diagnosis and prediction of early treatment response

Early brain functional changes induced by pharmacotherapy in patients with obsessive-compulsive disorder (OCD) in relation to drugs per se or because of the impact of such drugs on the improvement of OCD remain unclear. Moreover, no neuroimaging biomarkers are available for diagnosis of OCD and prediction of early treatment response. We performed a longitudinal study involving 34 patients with OCD and 36 healthy controls (HCs). Patients with OCD received 5-week treatment with paroxetine (40 mg/d). Resting-state functional magnetic resonance imaging (fMRI), regional homogeneity (ReHo), support vector machine (SVM), and support vector regression (SVR) were applied to acquire and analyze the imaging data. Compared with HCs, patients with OCD had higher ReHo values in the right superior temporal gyrus and bilateral hippocampus/parahippocampus/fusiform gyrus/cerebellum at baseline. ReHo values in the left hippocampus and parahippocampus decreased significantly after treatment. The reduction rate (RR) of ReHo values was positively correlated with the RRs of the scores of Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) and obsession. Abnormal ReHo values at baseline could serve as potential neuroimaging biomarkers for OCD diagnosis and prediction of early therapeutic response. This study highlighted the important role of the hippocampal-cortical system in the neuropsychological mechanism underlying OCD, pharmacological mechanism underlying OCD treatment, and the possibility of building models for diagnosis and prediction of early treatment response based on spontaneous activity in the hippocampal-cortical system.

Poorer Well-Being in Children With Misophonia: Evidence From the Sussex Misophonia Scale for Adolescents

Objective

Misophonia is an unusually strong aversion to a specific class of sounds - most often human bodily sounds such as chewing, crunching, or breathing. A number of studies have emerged in the last 10 years examining misophonia in adults, but little is known about the impact of the condition in children. Here we set out to investigate the well-being profile of children with misophonia, while also presenting the first validated misophonia questionnaire for children.

Materials and Methods

We screened 142 children (10-14 years; Mean 11.72 SD 1.12; 65 female, 77 male) using our novel diagnostic [the Sussex Misophonia Scale for Adolescents (SMS-Adolescent)]. This allowed us to identify a group of children already manifesting misophonia at that age - the first population-sampled cohort of child misophonics examined to date. Children and their parents also completed measures of well-being (for convergent validation of our SMS-Adolescent) and creative self-construct (for discriminant validation).

Results

Data show that children with misophonia have significantly elevated levels of anxiety and obsessive compulsive traits. Additionally children with misophonia have significantly poorer life-satisfaction, and health-related quality of life. As predicted, they show no differences in creative self-construct.

Conclusion

Together our data suggest the first evidence in population sampling of poorer life outcomes for children with misophonia, and provide preliminary convergent and discriminant validation for our novel misophonia instrument. Our data suggest a need for greater recognition and therapeutic outlets for adolescents with misophonia.

Obsessive-compulsive disorder-contamination fears, features, and treatment: novel smartphone therapies in light of global mental health and pandemics (COVID-19)

This review aims to shed light on the symptoms of obsessive-compulsive disorder (OCD) with a focus on contamination fears. In addition, we will briefly review the current therapies for OCD and detail what their limitations are. A key focus will be on discussing how smartphone solutions may provide approaches to novel treatments, especially when considering global mental health and the challenges imposed by rural environments and limited resources; as well as restrictions imposed by world-wide pandemics such as COVID-19. In brief, research that questions this review will seek to address include: (1) What are the symptoms of contamination-related OCD? (2) How effective are current OCD therapies and what are their limitations? (3) How can novel technologies help mitigate challenges imposed by global mental health and pandemics/COVID-19.

Avoidance of negative emotional contrast from worry and rumination: An application of the Contrast Avoidance Model

According to the Contrast Avoidance model (CAM), worry causes increased and sustained negative affect and such negative affect enables avoidance of a future sharp increase in negative emotion. However, only pathological worriers (vs. controls) view worry as a positive coping strategy to avoid a negative emotional contrast (NEC). We examined if rumination, which is another type of repetitive negative thought, would function similarly. Individuals with self-reported symptoms of pure generalized anxiety disorder (GAD; n = 90), pure depression (MDD; n = 85), and non-anxious/non-depressed controls (HC; n = 93) were randomly assigned to conditions where they were asked to worry, ruminate, or relax. Emotional and physiological changes were measured during worry and subsequent exposure to fearful and sad videos. We also assessed participant group differences in preference for worry or rumination as a strategy to cope with negative affect during the negative emotional video exposures. Consistent with CAM, regardless of the group, both worry and rumination enabled avoidance of NEC. Whereas worry led to greater avoidance of a fear contrast, rumination led to greater avoidance of a sadness contrast. On the other hand, relaxation enhanced NEC. Skin conductance also indicated patterns in line with CAM. In the subjectively perceived preference, the GAD group reported a greater preference for worry in coping with a fear contrast than HC. However, such a salient pattern was not found for the MDD group. Treatment implications of these findings are discussed.

Common and distinct neurofunctional representations of core and social disgust in the brain: Coordinate-based and network meta-analyses

Disgust represents a multifaceted defensive-avoidance response. On the behavioral level, the response includes withdrawal and a disgust-specific facial expression. While both serve the avoidance of pathogens, the latter additionally transmits social-communicative information. Given that common and distinct brain representation of the primary defensive-avoidance response (core disgust) and encoding of the social-communicative signal (social disgust) remain debated, we employed neuroimaging meta-analyses to (1) determine brain systems generally engaged in disgust processing, and (2) segregate common and distinct brain systems for core and social disgust. Disgust processing, in general, engaged a bilateral network encompassing the insula, amygdala, occipital and prefrontal regions. Core disgust evoked stronger reactivity in left-lateralized threat detection and defensive response network including amygdala, occipital and frontal regions, while social disgust engaged a right-lateralized superior temporal-frontal network engaged in social cognition. Anterior insula, inferior frontal and fusiform regions were commonly engaged during core and social disgust, suggesting a shared neurofunctional basis. We demonstrate a common and distinct neural basis of primary disgust responses and encoding of associated social-communicative signals.

Symptom provocation in obsessive-compulsive disorder: A voxel-based meta-analysis and meta-analytic connectivity modeling

BACKGROUND

Obsessive-compulsive disorder (OCD) is a heterogeneous psychiatric illness with a complex array of symptoms and potentially distinct neural underpinnings. We employed meta-analysis and connectivity modeling of symptom dimensions to delineate the circuit mechanisms of OCD.

METHODS

With the activation likelihood estimation (ALE) algorithm we performed meta-analysis of whole-brain functional magnetic resonance imaging (fMRI) studies of symptom provocation. We contrasted all OCD patients and controls in a primary analysis and divided the studies according to clinical symptoms in secondary meta-analyses. Finally, we employed meta-analytic connectivity modeling analyses (MACMs) to examine co-activation patterns of the brain regions revealed in the primary meta-analysis.

RESULTS

A total of 14 experiments from 12 eligible studies with a total of 238 OCD patients (124 men) and 219 healthy controls (120 men) were included in the primary analysis. OCD patients showed higher activation in the right caudate body/putamen/insula and lower activation in the left orbitofrontal cortex (OFC), left inferior frontal gyrus (IFG), left caudate body/middle cingulate cortex (MCC), right middle temporal gyrus (MTG), middle occipital gyrus (MOG) and right lateral occipital gyrus (LOG). MACMs revealed significant co-activation between left IFG and left caudate body/MCC, left MOG and right LOG, right LOG and MTG. In the secondary meta-analyses, the washing subgroup showed higher activation in the right OFC, bilateral ACC, left MOG and right caudate body.

CONCLUSION

OCD patients showed elevated dorsal striatal activation during symptom provocation. In contrast, the washing subgroup engaged higher activation in frontal, temporal and posterior cortical structures as well as right caudate body. Broadly consistent with the proposition of cortico-striatal-thalamic-cortical circuit dysfunction, these findings highlight potentially distinct neural circuits that may underlie the symptoms and potentially etiological subtypes of OCD.

A Unified Functional Network Target for Deep Brain Stimulation in Obsessive-Compulsive Disorder

BACKGROUND

Multiple deep brain stimulation (DBS) targets have been proposed for treating intractable obsessive-compulsive disorder (OCD). Here, we investigated whether stimulation effects of different target sites would be mediated by one common or several segregated functional brain networks.

METHODS

First, seeding from active electrodes of 4 OCD patient cohorts (N = 50) receiving DBS to anterior limb of the internal capsule or subthalamic nucleus zones, optimal functional connectivity profiles for maximal Yale-Brown Obsessive Compulsive Scale improvements were calculated and cross-validated in leave-one-cohort-out and leave-one-patient-out designs. Second, we derived optimal target-specific connectivity patterns to determine brain regions mutually predictive of clinical outcome for both targets and others predictive for either target alone. Functional connectivity was defined using resting-state functional magnetic resonance imaging data acquired in 1000 healthy participants.

RESULTS

While optimal functional connectivity profiles showed both commonalities and differences between target sites, robust cross-predictions of clinical improvements across OCD cohorts and targets suggested a shared network. Connectivity to the anterior cingulate cortex, insula, and precuneus, among other regions, was predictive regardless of stimulation target. Regions with maximal connectivity to these commonly predictive areas included the insula, superior frontal gyrus, anterior cingulate cortex, and anterior thalamus, as well as the original stereotactic targets.

CONCLUSIONS

Pinpointing the network modulated by DBS for OCD from different target sites identified a set of brain regions to which DBS electrodes associated with optimal outcomes were functionally connected-regardless of target choice. On these grounds, we establish potential brain areas that could prospectively inform additional or alternative neuromodulation targets for obsessive-compulsive disorder.

Interoception and Obsessive-Compulsive Disorder: A Review of Current Evidence and Future Directions

Disrupted interoceptive processes are present in a range of psychiatric conditions, and there is a small but growing body of research on the role of interoception in obsessive-compulsive disorder (OCD). In this review, we outline dimensions of interoception and review current literature on the processing of internal bodily sensations within OCD. Investigations in OCD utilizing objective measures of interoception are limited and results mixed, however, the subjective experience of internal bodily sensations appears to be atypical and relate to specific patterns of symptom dimensions. Further, neuroimaging investigations suggest that interoception is related to core features of OCD, particularly sensory phenomena and disgust. Interoception is discussed in the context of treatment by presenting an overview of existing interventions and suggesting how modifications aimed at better targeting interoceptive processes could serve to optimize outcomes. Interoception represents a promising direction for multi-method research in OCD, which we expect, will prove useful for improving current interventions and identifying new treatment targets.

Specialty knowledge and competency standards for pharmacotherapy for adult obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) affects approximately one person in 40 and causes substantial suffering. Evidence-based treatments can benefit many; however, optimal treatment can be difficult to access. Diagnosis is frequently delayed, and pharmacological and psychotherapeutic interventions often fail to follow evidence-based guidelines. To ameliorate this distressing situation, the International OCD Accreditation Task Force of the Canadian Institute for Obsessive-Compulsive Disorders has developed knowledge and competency standards for specialized treatments for OCD through the lifespan. These are foundational to evidence-based practice and will form the basis for upcoming ATF development of certification/accreditation programs. Here, we present specialty standards for the pharmacological treatment of adult OCD. We emphasize the importance of integrating pharmacotherapy with clear diagnosis, appreciation of complicating factors, and evidence-based cognitive behavioral therapy. Clear evidence exists to inform first- and second-line pharmacological treatments. In disease refractory to these initial efforts, multiple strategies have been investigated, but the evidence is more equivocal. These standards summarize this limited evidence to give the specialist practitioner a solid basis on which to make difficult decisions in complex cases. It is hoped that further research will lead to development of a clear, multi-step treatment algorithm to support each step in clinical decision-making.

Functional Brain Imaging and OCD

In the last 20 years, functional magnetic resonance imaging (fMRI) has been extensively used to investigate system-level abnormalities in the brain of patients with obsessive-compulsive disorder (OCD). In this chapter, we start by reviewing the studies assessing regional brain differences between patients with OCD and healthy controls in task-based fMRI. Specifically, we review studies on executive functioning and emotional processing, protocols in which these patients have been described to show alterations at the behavioral level, as well as research using symptom provocation protocols. Next, we review studies on brain connectivity alterations, focusing on resting-state studies evaluating disruptions in fronto-subcortical functional connectivity and in cortical networks. Likewise, we also review research on effective connectivity, which, different from functional connectivity, allows for ascertaining the directionality of inter-regional connectivity alterations. We conclude by reviewing the most significant findings on a topic of translational impact, such as the use of different fMRI measurements to predict response across a variety of treatment approaches. Overall, results suggest that there exists a pattern of regions, involving, but not limited to, different nodes of the cortico-striatal-thalamo-cortical circuits, showing robust evidence of functional alteration across studies, although the nature of the alterations critically depends on the specific tasks and their particular demands. Moreover, such findings have been, to date, poorly translated into clinical practice. It is suggested that this may be partially accounted for by the difficulty to integrate into a common framework results obtained under a wide variety of analysis approaches.

Animal Models for OCD Research

OCD has lagged behind other psychiatric illnesses in the identification of molecular treatment targets, due in part to a lack of significant findings in genome-wide association studies. However, while progress in this area is being made, OCD's symptoms of obsessions, compulsions, and anxiety can be deconstructed into distinct neural functions that can be dissected in animal models. Studies in rodents and non-human primates have highlighted the importance of cortico-basal ganglia-thalamic circuits in OCD pathophysiology, and emerging studies in human post-mortem brain tissue point to glutamatergic synapse abnormalities as a potential cellular substrate for observed dysfunctional behaviors. In addition, accumulated evidence points to a potential role for neuromodulators including serotonin and dopamine in both OCD pathology and treatment. Here, we review current efforts to use animal models for the identification of molecules, cell types, and circuits relevant to OCD pathophysiology. We start by describing features of OCD that can be modeled in animals, including circuit abnormalities and genetic findings. We then review different strategies that have been used to study OCD using animal model systems, including transgenic models, circuit manipulations, and dissection of OCD-relevant neural constructs. Finally, we discuss how these findings may ultimately help to develop new treatment strategies for OCD and other related disorders.

Deep brain stimulation modulates directional limbic connectivity in obsessive-compulsive disorder

Deep brain stimulation is effective for patients with treatment-refractory obsessive-compulsive disorder. Deep brain stimulation of the ventral anterior limb of the internal capsule rapidly improves mood and anxiety with optimal stimulation parameters. To understand these rapid effects, we studied functional interactions within the affective amygdala circuit. We compared resting state functional MRI data during chronic stimulation versus 1 week of stimulation discontinuation in patients, and obtained two resting state scans from matched healthy volunteers to account for test-retest effects. Imaging data were analysed using functional connectivity analysis and dynamic causal modelling. Improvement in mood and anxiety following deep brain stimulation was associated with reduced amygdala-insula functional connectivity. Directional connectivity analysis revealed that deep brain stimulation increased the impact of the ventromedial prefrontal cortex on the amygdala, and decreased the impact of the amygdala on the insula. These results highlight the importance of the amygdala circuit in the pathophysiology of obsessive-compulsive disorder, and suggest a neural systems model through which negative mood and anxiety are modulated by stimulation of the ventral anterior limb of the internal capsule for obsessive-compulsive disorder and possibly other psychiatric disorders.

Insula Volume in Patients Diagnosed with Obsessive Compulsive Disorder and its Relation with Clinical Variables

Introduction

Neuroimaging studies performed in recent years on patients with obsessive compulsive disorder have determined anomalies that are possibly associated with the determinant signs and symptoms of the disease. The purpose of this study is to investigate the morphometric changes in insula volume and related parameters in order to understand the etiopathogenesis of obsessive compulsive disorder better.

Method

Throughout the study, 20 patients eligible for the study criteria, who were diagnosed with OCD according to DSM-5 diagnostic criteria and receiving inpatient or outpatient treatment after applying to Fırat University Hospital Psychiatry Department, and 13 healthy subjects in the control group have been included in the study. Sociodemographic and Clinical Data Form, Hamilton Depression Rating Scale (HAM-D), Hamilton Anxiety Rating Scale (HAM-A), Yale-Brown Obsession Compulsive Scale (Y-BOCS) and SCID-I have been applied to the patients. Volumetric measurements were performed on the insula by using magnetic resonance imaging (MRI) in patient and control groups.

Results

No significant difference was observed between patients with Obsessive Compulsive Disorder and healthy controls with regard to insula volume.

Discussion

It may be stated that insula may be associated with both the pathophysiology and clinical course of the disease. It is suggested that studies considering the imaging methods examining the functional characteristics of this area and tests on cognitive functions together may lead to significant and efficient results.

Individual traits that influence the frequency and emotional characteristics of involuntary musical imagery: An experience sampling study

In this study, we investigated individual traits that influence the frequency of involuntary musical imagery (INMI) and the emotional valence of these occurrences using the experience sampling method (ESM) that measures INMI in daily life at the moment they occur. As individual traits, the effects of non-clinical obsessive-compulsive (OC) tendencies, personality traits, and musical expertise were examined. Among them, we were particularly interested in the effect of OC tendencies that are assumed to be related to INMI but are yet to be fully examined using ESM. A total of 101 university students completed questionnaires that assessed OC tendencies, the Big Five personality traits, and musical expertise. During the seven-day sampling period, participants received smartphone notifications six times per day and responded by stating whether they had experienced INMI and described the emotional characteristics of those occurrences. A multilevel analysis showed the relationship between OC tendencies and INMI. A positive effect was observed for intrusive thoughts (obsession) on the occurrence of INMI. Regarding the emotional characteristics of INMI, a negative effect of compulsive washing was observed on both the pleasantness of INMI experiences and the extent to which the participants liked the music they had heard internally. The effects of both personality traits and musical expertise were also observed in the analysis of INMI occurrences, both of which are consistent with previous findings. In summary, the present study using ESM supports previous findings on individual traits that affect INMI and clarifies them with additional detail and accuracy.

Global Image Properties Predict Ratings of Affective Pictures

Affective pictures are widely used in studies of human emotions. The objects or scenes shown in affective pictures play a pivotal role in eliciting particular emotions. However, affective processing can also be mediated by low-level perceptual features, such as local brightness contrast, color or the spatial frequency profile. In the present study, we asked whether image properties that reflect global image structure and image composition affect the rating of affective pictures. We focused on 13 global image properties that were previously associated with the esthetic evaluation of visual stimuli, and determined their predictive power for the ratings of five affective picture datasets (IAPS, GAPED, NAPS, DIRTI, and OASIS). First, we used an SVM-RBF classifier to predict high and low ratings for valence and arousal, respectively, and achieved a classification accuracy of 58–76% in this binary decision task. Second, a multiple linear regression analysis revealed that the individual image properties account for between 6 and 20% of the variance in the subjective ratings for valence and arousal. The predictive power of the image properties varies for the different datasets and type of ratings. Ratings tend to share similar sets of predictors if they correlate positively with each other. In conclusion, we obtained evidence from non-linear and linear analyses that affective pictures evoke emotions not only by what they show, but they also differ by how they show it. Whether the human visual system actually uses these perceptive cues for emotional processing remains to be investigated.

Multi-Level Clustering of Dynamic Directional Brain Network Patterns and Their Behavioral Relevance

Dynamic functional connectivity (DFC) obtained from resting state functional magnetic resonance imaging (fMRI) data has been shown to provide novel insights into brain function which may be obscured by static functional connectivity (SFC). Further, DFC, and by implication how different brain regions may engage or disengage with each other over time, has been shown to be behaviorally relevant and more predictive than SFC of behavioral performance and/or diagnostic status. DFC is not a directional entity and may capture neural synchronization. However, directional interactions between different brain regions is another putative mechanism by which neural populations communicate. Accordingly, static effective connectivity (SEC) has been explored as a means of characterizing such directional interactions. But investigation of its dynamic counterpart, i.e., dynamic effective connectivity (DEC), is still in its infancy. Of particular note are methodological insufficiencies in identifying DEC configurations that are reproducible across time and subjects as well as a lack of understanding of the behavioral relevance of DEC obtained from resting state fMRI. In order to address these issues, we employed a dynamic multivariate autoregressive (MVAR) model to estimate DEC. The method was first validated using simulations and then applied to resting state fMRI data obtained in-house (N = 21), wherein we performed dynamic clustering of DEC matrices across multiple levels [using adaptive evolutionary clustering (AEC)] – spatial location, time, and subjects. We observed a small number of directional brain network configurations alternating between each other over time in a quasi-stable manner akin to brain microstates. The dominant and consistent DEC network patterns involved several regions including inferior and mid temporal cortex, motor and parietal cortex, occipital cortex, as well as part of frontal cortex. The functional relevance of these DEC states were determined using meta-analyses and pertained mainly to memory and emotion, but also involved execution and language. Finally, a larger cohort of resting-state fMRI and behavioral data from the Human Connectome Project (HCP) (N = 232, Q1–Q3 release) was used to demonstrate that metrics derived from DEC can explain larger variance in 70 behaviors across different domains (alertness, cognition, emotion, and personality traits) compared to SEC in healthy individuals.

Modality-specific overlaps in brain structure and function in obsessive-compulsive disorder: Multimodal meta-analysis of case-control MRI studies

Neuroimaging research has shown that patients with obsessive-compulsive disorder (OCD) may present brain structural and functional alterations, but the results across imaging modalities and task paradigms are difficult to reconcile. Are the same brain systems that are structurally different in OCD patients also involved in executive function and emotional processing? To answer this, we conducted separate meta-analyses of voxel-based morphometry studies, executive function functional magnetic resonance imaging (fMRI) studies, and emotional processing fMRI studies. Next, with a multimodal approach (conjunction analysis), we identified the common alterations across meta-analyses. Patients presented increased gray matter volume and hyperactivation in the putamen, but the putamen subregions affected differed depending on the psychological process. Left posterior/dorsal putamen showed hyperactivation during executive processing tasks, while predominantly right anterior/ventral putamen showed hyperactivation during emotional processing tasks. Interestingly, age was significantly associated with increased right putamen volume. Finally, the left dorsolateral prefrontal cortex was hyperactive in both functional domains. Our findings highlight task-specific correlates of brain structure and function in OCD and help integrate a growing literature.

Neural correlates of symptom provocation in pediatric obsessive-compulsive disorder

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Largest controlled pediatric OCD symptom provocation study.

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Novel standardized symptom provocation picture set for pediatric OCD.

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Behavioral group differences strongest for ‘Just Right’ factor.

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Temporal pole recruited by OCD group.

Obsessive-compulsive disorder

(OCD)-affected adults and children exhibit three to four symptom dimensions with distinct but overlapping neural correlates. No symptom provocation behavioural or imaging study has examined all symptom dimensions in a pediatric OCD sample.

Method

Clinically diagnosed pediatric OCD-affected participants (n = 25) as well as age, gender and Tanner pubertal stage-matched healthy controls (HCs; n = 24) (total sample: mean age = 14.77 ± 2.93 years; age range = 9–18 years; 35% male) viewed alternating blocks of OCD symptom provocation (Contamination, Bad Thoughts, and Just Right symptom dimensions), Fear, Neutral and Rest (i.e. fixation) conditions during functional magnetic resonance imaging. A region-of-interest analysis used seeds based upon results of an adult OCD meta-analysis

Results

OCD participants found OCD symptom-related stimuli bothersome, particularly when compared to controls in the “Just Right” symptom dimension. Pediatric OCD patients exhibited greater recruitment of the left superior temporal gyrus (STG) than healthy controls during combined symptom provocation versus neutral conditions.

Conclusion

Findings suggest involvement of the temporal poles rather than in classic cortico-striatal-thalamico-cortical circuits in pediatric OCD during symptom provocation.

Sertraline Effects on Striatal Resting-State Functional Connectivity in Youth With Obsessive-Compulsive Disorder: A Pilot Study

OBJECTIVE

Foundational knowledge on neural circuitry underlying pediatric obsessive-compulsive disorder (OCD) and how it changes during standard treatment is needed to provide the basis for conceptualization and development of novel targeted treatments. This study explored the effects of sertraline, a selective serotonin reuptake inhibitor, on resting-state functional connectivity in cortico-striatal-thalamic-cortical circuits in pediatric OCD.

METHOD

Medication-free youths with OCD (n = 14) and healthy controls (n = 14) were examined at baseline and 12 weeks with resting-state functional magnetic resonance imaging. Between scan sessions, participants with OCD received 12 weeks of sertraline. For each scan, seed-based whole-brain resting-state functional connectivity analyses were conducted with 6 striatal seeds. Analysis of variance examined the interaction between group and time on striatal connectivity, including cluster-based thresholding to correct for multiple tests. Connectivity changes within circuits identified in group analyses were correlated with clinical change.

RESULTS

Two significant group-by-time effects in the OCD group showed increased striatal connectivity from baseline to 12 weeks compared with controls. Circuits demonstrating this pattern included the right putamen with the left frontal cortex and insula and the left putamen with the left frontal cortex and pre- and post-central cortices. Increase in connectivity in the left putamen circuit was significantly correlated with clinical improvement on the Children's Yale-Brown Obsessive-Compulsive Scale score (r = -0.58, p = .03).

CONCLUSION

Sertraline appears to affect specific striatal-based circuits in pediatric OCD, and these changes in part could account for clinical improvement. Future work is needed to confirm these preliminary findings, which would facilitate identification of circuit-based targets for novel treatment development.

CLINICAL TRIAL REGISTRATION INFORMATION

Effects of Sertraline on Brain Connectivity in Adolescents with OCD; https://clinicaltrials.gov/; NCT02797808.

Empathy in Facial Mimicry of Fear and Disgust: Simultaneous EMG-fMRI Recordings During Observation of Static and Dynamic Facial Expressions

Real-life faces are dynamic by nature, particularly when expressing emotion. Increasing evidence suggests that the perception of dynamic displays enhances facial mimicry and induces activation in widespread brain structures considered to be part of the mirror neuron system, a neuronal network linked to empathy. The present study is the first to investigate the relations among facial muscle responses, brain activity, and empathy traits while participants observed static and dynamic (videos) facial expressions of fear and disgust. During display presentation, blood-oxygen level-dependent (BOLD) signal as well as muscle reactions of the corrugator supercilii and levator labii were recorded simultaneously from 46 healthy individuals (21 females). It was shown that both fear and disgust faces caused activity in the corrugator supercilii muscle, while perception of disgust produced facial activity additionally in the levator labii muscle, supporting a specific pattern of facial mimicry for these emotions. Moreover, individuals with higher, compared to individuals with lower, empathy traits showed greater activity in the corrugator supercilii and levator labii muscles; however, these responses were not differentiable between static and dynamic mode. Conversely, neuroimaging data revealed motion and emotional-related brain structures in response to dynamic rather than static stimuli among high empathy individuals. In line with this, there was a correlation between electromyography (EMG) responses and brain activity suggesting that the Mirror Neuron System, the anterior insula and the amygdala might constitute the neural correlates of automatic facial mimicry for fear and disgust. These results revealed that the dynamic property of (emotional) stimuli facilitates the emotional-related processing of facial expressions, especially among whose with high trait empathy.

Affective modulation of the associative-limbic subthalamic nucleus: deep brain stimulation in obsessive-compulsive disorder

Affective states underlie daily decision-making and pathological behaviours relevant to obsessive-compulsive disorders (OCD), mood disorders and addictions. Deep brain stimulation targeting the motor and associative-limbic subthalamic nucleus (STN) has been shown to be effective for Parkinson's disease (PD) and OCD, respectively. Cognitive and electrophysiological studies in PD showed responses of the motor STN to emotional stimuli, impairments in recognition of negative affective states and modulation of the intensity of subjective emotion. Here we studied whether the stimulation of the associative-limbic STN in OCD influences the subjective emotion to low-intensity positive and negative images and how this relates to clinical symptoms. We assessed 10 OCD patients with on and off STN DBS in a double-blind randomized manner by recording ratings of valence and arousal to low- and high-intensity positive and negative emotional images. STN stimulation increased positive ratings and decreased negative ratings to low-intensity positive and negative stimuli, respectively, relative to off stimulation. We also show that the change in severity of obsessive-compulsive symptoms pre- versus post-operatively interacts with both DBS and valence ratings. We show that stimulation of the associative-limbic STN might influence the negative cognitive bias in OCD and decreasing the negative appraisal of emotional stimuli with a possible relationship with clinical outcomes. That the effect is specific to low intensity might suggest a role of uncertainty or conflict related to competing interpretations of image intensity. These findings may have implications for the therapeutic efficacy of DBS.

Individual OCD-provoking stimuli activate disorder-related and self-related neuronal networks in fMRI

For patients with Obsessive-Compulsive Disorder (OCD), whose triggers are highly idiosyncratic, individual stimulus material has been used in several fMRI studies. This study aims at comparing individual to standardized picture sets and at investigating a possible overlap of the former with the self-referential neuronal network. During fMRI-scanning, 17 inpatients with OCD and 17 healthy controls were exposed to pictures of their personal triggers, photographed in their domestic environments, to standardized pictures designed to provoke OCD symptoms, and to neutral pictures. Whole-brain analyses were calculated and the pictures were rated by both patients and controls with respect to valence, arousal, and coping. Patients rated the individualized stimuli lower in valence and coping and higher in arousal compared to controls, and also compared to standardized OCD- and neutral stimuli. The individual stimuli elicited neuronal activity in the cingulate cortex, hippocampus, insula, middle frontal/precentral gyrus, superior/inferior parietal lobe, and precuneus, while no group difference was detected by the standardized OCD-stimuli. In conclusion, individual picture sets facilitate the detection of neuronal activity, but the results might be confounded due to the overlap with the network of self-referential processing and memory retrieval. The use of individual symptom-provoking and individual neutral stimuli would therefore be optimal.

Abnormal Regional Homogeneity in Patients With Obsessive-Compulsive Disorder and Their Unaffected Siblings: A Resting-State fMRI Study

Objective: Previous studies suggest that abnormal brain structure and function may be neuroimaging endophenotypes of obsessive-compulsive disorder (OCD). Comparing the intrinsic brain activity of OCD patients and their unaffected siblings will help to further understand the susceptibility to, and pathological mechanisms of, OCD. We used a case-control study design aiming to establish whether the abnormal regional homogeneity (ReHo) found in OCD patients also exists in their unaffected siblings. Method: Fifteen unmedicated OCD patients, 15 of their unaffected siblings, and 30 healthy controls (HCs) received resting-state functional magnetic resonance imaging (r-s fMRI) scanning and clinical evaluation. We used the ReHo method to analyze the inter-regional synchronized activity of all participants. One-way analysis of covariance with post hoc tests was used to compare the ReHo maps across groups. A Pearson correlation analysis was conducted to assess the correlations between clinical characteristics and abnormal ReHo in OCD patients. Results: Relative to HCs, OCD patients and their unaffected siblings showed overlapping higher ReHo values in the right dorsolateral prefrontal cortex (DLPFC). Patients with OCD showed increased ReHo in left middle frontal gyrus (MFG) relative to both their unaffected siblings and HCs. In addition to the right DLPFC and left MFG, OCD patients, compared with HCs, also showed abnormal ReHo in other regions, including higher ReHo in the right superior parietal cortex and lower ReHo in the left inferior parietal cortex, right parahippocampal region, left thalamus, and right inferior temporal cortex. Compared with HCs, the unaffected siblings of patients with OCD had significantly higher ReHo in the right inferior parietal cortex, right MFG, and right supplementary motor area. There was no association between clinical symptoms and abnormal ReHo values in OCD patients. Conclusions: This study found overlapping higher ReHo values in the right DLPFC of OCD patients and their unaffected siblings. Our results suggest that the higher ReHo in the right DLPFC may be a potential neuroimaging endophenotype, which may reflect an increased genetic risk of OCD.

Use of an Individual-Level Approach to Identify Cortical Connectivity Biomarkers in Obsessive-Compulsive Disorder

BACKGROUND

Existing functional connectivity studies of obsessive-compulsive disorder (OCD) support a model of circuit dysfunction. However, these group-level observations have failed to yield neuroimaging biomarkers sufficient to serve as a test for the OCD diagnosis, predict current or future symptoms, or predict treatment response, perhaps because these studies failed to account for the substantial intersubject variability in structural and functional brain organization.

METHODS

We used functional regions, localized in each of 41 individual OCD patients, to identify cortical connectivity biomarkers of both global and dimension-specific symptom severity and to detect functional connections that track changes in symptom severity following intensive residential treatment.

RESULTS

Global OCD symptom severity was directly linked to dysconnectivity between large-scale intrinsic brain networks-particularly among the dorsal attention, default, and frontoparietal networks. Changes within a subset of connections among these networks were associated with symptom resolution. Additionally, distinct and nonoverlapping cortical connectivity biomarkers were identified that were significantly associated with the severity of contamination/washing and responsibility for harm/checking symptoms, highlighting the contribution of dissociable neural networks to specific OCD symptom dimensions. By contrast, when we defined functional regions conventionally, using a population-level brain atlas, we could no longer identify connectivity biomarkers of severity or improvement for any of the symptom dimensions.

CONCLUSIONS

Our findings would seem to encourage the use of individual-level approaches to connectivity analyses to better delineate the cortical and subcortical networks underlying symptom severity and improvement at the dimensional level in OCD patients.

Disgust in Anxiety and Obsessive-Compulsive Disorders: Recent Findings and Future Directions

PURPOSE OF REVIEW

In the past 20 years, the role of disgust in anxiety disorders and obsessive-compulsive disorder (OCD) has been investigated with increasing precision. In this review, we examine recent evidence implicating disgust in anxiety and OCD, highlighting recent measurement and methodological improvements. Specific emphasis is placed on understanding the mechanisms that may account for the role of disgust in OCD and related disorders.

RECENT FINDINGS

Recent developments include clarification of the role of distinct disgust-relevant vulnerabilities in the etiology of anxiety and OCD, an improved understanding of the neurobiology of disgust processing in OCD, and an increased focus on disgust-related mechanisms that contribute to psychopathology, such as disgust-based learning and emotion regulation. Disgust proneness is increasingly linked with symptoms of anxiety and OCD. However, further examination of the mechanisms that account for the roles of distinct disgust-relevant vulnerabilities is needed, and studies that directly examine disgust during the course of treatment are limited. Increasingly, the field has moved toward experimental investigation of specific disgust-relevant mechanisms that influence the etiology and treatment of OCD and related anxiety disorders.

Decoding moral emotions in obsessive-compulsive disorder

Background

Patients with obsessive-compulsive disorder (OCD) exhibit abnormal neural responses when they experience particular emotions or when they evaluate stimuli with emotional value. Whether these brain responses are sufficiently distinctive to discriminate between OCD patients and healthy controls is unknown. The present study is the first to investigate the discriminative power of multivariate pattern analysis of regional fMRI responses to moral and non-moral emotions.

Method

To accomplish this goal, we performed a searchlight-based multivariate pattern analysis to unveil brain regions that could discriminate 18 OCD patients from 18 matched healthy controls during provoked guilt, disgust, compassion, and anger. We also investigated the existence of distinctive neural patterns while combining those four emotions (herein termed multiemotion analysis).

Results

We found that different frontostriatal regions discriminated OCD patients from controls based on individual emotional experiences. Most notably, the left nucleus accumbens (NAcc) discriminated OCD patients from controls during both disgust and the multiemotion analysis. Among other regions, the angular gyrus responses to anger and the lingual and the middle temporal gyri in the multi-emotion analysis were highly discriminant between samples. Additional BOLD analyses supported the directionality of these findings.

Conclusions

In line with previous studies, differential activity in regions beyond the frontostriatal circuitry differentiates OCD from healthy volunteers. The finding that the response of the left NAcc to different basic and moral emotions is highly discriminative for a diagnosis of OCD confirms current pathophysiological models and points to new venues of research.

Symptom dimensions in obsessive-compulsive disorder as predictors of neurobiology and treatment response

Purpose of review

Specific symptom dimensions of obsessive-compulsive disorder (OCD) have been suggested as an approach to reduce the heterogeneity of obsessive-compulsive disorder, predict treatment outcome, and relate to brain structure and function. Here, we review studies addressing these issues.

Recent findings

The contamination and symmetry/ordering dimensions have not been reliably associated with treatment outcome. Some studies found that greater severity of sexual/aggressive/religious symptoms predicted a worse outcome after cognitive behavioral therapy (CBT) and a better outcome after serotonin reuptake inhibitors (SRIs). Contamination symptoms have been related to increased amygdala and insula activation in a few studies, while sexual/aggressive/religious symptoms have also been related to more pronounced alterations in the function and structure of the amygdala. Increased pre-treatment limbic responsiveness has been related to better outcomes of CBT, but most imaging studies show important limitations and replication in large-scale studies is needed. We review possible reasons for the strong limbic involvement of the amygdala in patients with more sexual/aggressive/religious symptoms, in relation to their sensitivity to CBT.

Summary

Symptom dimensions may predict treatment outcome, and patients with sexual/religious/aggressive symptoms are at a greater risk of not starting or delaying treatment. This is likely partly due to more shame and perceived immorality which is also related to stronger amygdala response. Competently delivered CBT is likely to help these patients improve to the same degree as patients with other symptoms.

Novel ensemble method for the prediction of response to fluvoxamine treatment of obsessive-compulsive disorder

OBJECTIVE

About 30% of obsessive-compulsive disorder (OCD) patients exhibit an inadequate response to pharmacotherapy. The detection of clinical variables associated with treatment response may result in achievement of remission in shorter period, preventing illness development and reducing socioeconomic costs.

METHODS

In total, 330 subjects with OCD diagnosis underwent 12-week pharmacotherapy with fluvoxamine (150-300 mg). Treatment response was ≥25% reduction in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) score. In total, 36 clinical attributes of 151 subjects who had completed their treatment course were analyzed. Data mining algorithms included missing value handling, feature selection, and new analytical method based on ensemble classification. The results were compared with those of other traditional classification algorithms such as decision tree, support vector machines, k-nearest neighbor, and random forest.

RESULTS

Sexual and contamination obsessions are high-ranked predictors of resistance to fluvoxamine pharmacotherapy as well as high Y-BOCS obsessive score. Our results showed that the proposed analysis strategy has good ability to distinguish responder and nonresponder patients according to their clinical features with 86% accuracy, 79% sensitivity, and 89% specificity.

CONCLUSION

This study proposed an analytical approach which is an accurate and a sensitive method for the analysis of high-dimensional medical data sets containing more number of missing values. The treatment of OCD could be improved by better understanding of the predictors of pharmacotherapy, which may lead to more effective treatment of patients with OCD.

Low frequency fluctuation of brain spontaneous activity and obsessive-compulsive symptoms in a large school-age sample

BACKGROUND

The present study was designed to explore alterations in brain dynamics at rest that are associated with Obsessive Compulsive Symptoms (OCS) in childhood by measuring low frequency fluctuation of spontaneous brain activity in a large school community sample from a developing country.

METHOD

Resting state functional magnetic resonance imaging data were collected in a sample of 655 children and adolescents (6-15 years old) from the brazilian 'High Risk Cohort Study for Psychiatric Disorders (HRC)'. OCS were assessed using items from the Compulsion and Obsessions section of the Development and Well-Being Assessment (DAWBA). The correlation between the fractional amplitude of low frequency fluctuations (fALFF) and the number of OCS were explored by using a general linear model, considering fALFF as response variable, OCS score as regressor and age, gender and site as nuisance variables.

RESULTS

The number of OCS was positively correlated with the fALFF coefficients at the right sensorimotor cortex (pre-motor, primary motor cortex and post-central gyrus) and negatively correlated with the fALFF coefficients at the insula/superior temporal gyrus of both hemispheres. Our results were specific to OCS and not due to associations with overall psychopathology.

CONCLUSIONS

Our results suggest that brain spontaneous activity at rest in the sensorimotor and insular/superior-temporal cortices may be involved in OCS in children. These findings need independent replication and future studies should determine whether brain spontaneous activity changes within these regions might be predictors of risk for obsessive-compulsive disorder latter in life.

The effects of cognitive reappraisal on conditioned disgust in contamination-based OCD: An analogue study

Experimental research has shown that conditioned disgust is resistant to extinction, which may account for the slower habituation to disgust relative to fear in contamination-based obsessive-compulsive disorder (OCD). However, few studies have examined the efficacy of interventions that may attenuate conditioned disgust responses. Studies of cognitive reappraisal have demonstrated that reinterpreting a stimulus can alter emotional responding. This technique is based on cognitive theories which suggest that anxiety disorders arise from biased cognitions; therefore, changing a person's thoughts will elicit durable changes in emotional responses. Given the demonstrated effectiveness of cognitive reappraisal, the present study examined whether cognitive reappraisal would attenuate conditioned disgust responses. We conditioned participants high in contamination fear (n=55) using images of neutral food items (conditioned stimuli; CS) paired with videos of individuals vomiting (unconditioned stimuli; US) while we obtained subjective disgust reports. After conditioning, half of the participants were randomly assigned to cognitive reappraisal training aimed at decreasing their emotional response to the US and CS, while the other half received no such training. The findings showed that cognitive reappraisal participants demonstrated a reduction in learned disgust across sessions and further benefited from extinction. These findings suggest that cognitive reappraisal may be an effective strategy for attenuating learned disgust.

OCD: obsessive-compulsive … disgust? The role of disgust in obsessive-compulsive disorder

Recent research has identified the important role of disgust in the symptomatology of obsessive-compulsive disorder (OCD). Exaggerated and inappropriate disgust reactions may drive some of the symptoms of OCD, and in some cases, may even eclipse feelings of anxiety. This paper reviews behavioural and neuroimaging research that recognizes the prominent role of disgust in contributing to OCD symptoms, especially contamination-based symptoms. We discuss how elevated behavioural and biological markers of disgust reported in OCD populations support the need for alternative clinical treatment strategies and theoretical models of OCD.

Is Disgust Proneness Associated With Anxiety and Related Disorders? A Qualitative Review and Meta-Analysis of Group Comparison and Correlational Studies

Research suggests that disgust may be linked to the etiology of some anxiety-related disorders. The present investigation reviews this literature and employs separate meta-analyses of clinical group comparison and correlational studies to examine the association between disgust proneness and anxiety-related disorder symptoms. Meta-analysis of 43 group comparison studies revealed those high in anxiety disorder symptoms reported significantly more disgust proneness than those low in anxiety symptoms. Although this effect was not moderated by clinical versus analogue studies or type of disorder, larger group differences were observed for those high in anxiety symptoms associated with contagion concerns compared to those high in anxiety symptoms not associated with contagion concerns. Similarly, meta-analysis of correlational data across 83 samples revealed moderate associations between disgust proneness and anxiety-related disorder symptoms. Moderator analysis revealed that the association between disgust proneness and anxiety-related disorder symptoms was especially robust for anxiety symptoms associated with contagion concerns. After controlling for measures of negative affect, disgust proneness continued to be moderately correlated with anxiety-related disorder symptoms. However, negative affect was no longer significantly associated with symptoms of anxiety-related disorders when controlling for disgust proneness. The implications of these findings are discussed in the context of a novel transdiagnostic model.

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.

Altered olfactory processing and increased insula activity in patients with obsessive-compulsive disorder: An fMRI study

Obsessive-compulsive disorder (OCD) patients show increased insula activation to disgust-inducing images compared to healthy controls (HC). We explored whether this disgust reactivity was also present in the olfactory domain by conducting the first fMRI study of olfaction in OCD. Neural activation in response to pleasant and unpleasant odors (vs. unscented air) was investigated in 15 OCD and 15 HC participants using fMRI. OCD participants (vs. HC) had increased left anterior insula activation to unpleasant odors (vs. unscented air), which positively correlated with their disgust sensitivity and ratings of the unpleasantness and intensity of those odors. OCD participants (vs. HC) showed increased activation of caudate nucleus and left anterior and posterior insula to pleasant odors (vs. unscented air), which positively correlated with their OCD symptom severity, trait anxiety, frequency of feeling disgust, and odor intensity ratings. OCD participants had increased anterior insula activation to both pleasant and unpleasant odors, which correlated with their OCD symptoms, anxiety, disgust sensitivity, and frequency of feeling disgust. OCD patients might have a negative cognitive bias and experience all stimuli, regardless of valence, as being more unpleasant than healthy people. These findings further elucidate the neural underpinnings of OCD and may contribute to more effective treatments.

Is disgust proneness sensitive to treatment for OCD among youth?: Examination of diagnostic specificity and symptom correlates

Although disgust proneness has been implicated in obsessive-compulsive disorder (OCD), there is a paucity of research examining change in disgust proneness during treatment as well as the correlates of such change, especially in children. This study examined the relationship between changes in disgust proneness and disorder-specific symptoms during residential treatment among youth with OCD, anxiety, and mood disorders. Youth ages 12-18 (n=472) completed pre- and post-outcome measures of OCD, anxiety, and mood symptoms and disgust proneness. Results indicate that although disgust proneness decreases during treatment for youth with OCD, anxiety, and mood disorders, youth with primary OCD experienced the greatest decrease in disgust proneness over the course of treatment. Reductions in disgust proneness during treatment were significantly correlated with reductions in multiple symptom measures, with the strongest correlations between reductions in disgust proneness and OCD symptoms. Implications and directions for future research are discussed.

Neuroanatomical assessment of the impact of negative emotion on implicit memory in patients with obsessive compulsive disorder

OBJECTIVE

We performed functional magnetic resonance imaging (fMRI) to discriminate the differential brain activation patterns in patients with obsessive compulsive disorder (OCD) and healthy controls during implicit retrieval tasks with emotionally neutral and unpleasant words.

METHODS

Sixteen patients with OCD (mean age: 31.4±10.1 years) and 16 healthy controls (mean age: 32.6±5.8 years) with no history of neurological or psychiatric illness underwent 3-T fMRI. The stimulation paradigm consisted of the following cycle: rest, encoding of a string of two-syllable words, rest, and retrieval of the previously encoded words with the first consonant omitted.

RESULTS

During the implicit retrieval task with emotionally neutral words, no distinct brain activity was observed in either the patients with OCD or healthy controls. On the other hand, during the retrieval task with unpleasant words, the patients with OCD showed predominant activity in the superior/middle temporal pole, medial superior frontal gyrus, and orbitofrontal cortex (uncorrected p<0.001, extent threshold: 30 voxels), whereas the healthy controls did not show any distinct regions of activation.

CONCLUSION

This study revealed the differential brain activation patterns between patients with OCD and healthy controls during implicit memory tasks with unpleasant words. Our results suggest that the impact of negative emotion on implicit memory task may be associated with the symptomatology of OCD. This finding may be helpful for understanding the neural mechanisms that underlie implicit memory retrieval, particularly the interaction between emotion and cognition, in patients with OCD.