Structural neuroimaging of skin-picking disorder.

BACKGROUND: Skin-picking disorder (SPD) is conceptualized as an obsessive-compulsive and related disorder (OCRD). Patients with SPD excessively manipulate their skin, which leads to skin lesions, psychological distress, and functional impairment. The neuroanatomical facets of this disorder are still poorly understood. METHODS: A total of 220 participants (123 patients with a primary diagnosis of SPD and 97 healthy controls; mean age = 30 years, 80% female) were recruited for a voxel-based morphometry (VBM) study. VBM data were compared between patients and controls, and between three SPD subgroups, each characterized by a distinct age of symptom onset (before puberty, during puberty, adulthood). RESULTS: Relative to the healthy comparison group, patients with SPD had significantly less grey matter volume (GMV) in regions of interest (ROIs: insula, orbitofrontal cortex, pallidum, cerebellum, supramarginal gyrus) and in the frontal pole and occipital regions (whole-brain findings). Early onset of symptoms (before puberty) was associated with elevated levels of focused skin-picking, in addition to less GMV in specific ROIs (insula, orbitofrontal cortex) as well as in paracingulate/ superior temporal regions (whole-brain findings). CONCLUSIONS: SPD-related reductions in GMV were identified in brain regions involved in interoception, emotion regulation, and motor control. This partially aligns with findings for OCD. The detection of different age-of-onset groups based on clinical as well as morphometric data points to the heterogeneity of the disorder and warrants further investigation.

The pill you don't have to take that is still effective: neural correlates of imaginary placebo intake for regulating disgust.

A commonly established protocol for the administration of open-label placebos (OLPs)-placebos honestly prescribed-emphasizes the necessity of ingesting the pill for the placebo effect to manifest. The current functional magnetic resonance imaging study used a novel approach to OLP administration: the imaginary intake of an OLP pill for regulating disgust. A total of 99 females were randomly allocated to one of three groups that either swallowed a placebo pill (OLP Pill), imagined the intake of a placebo pill (Imaginary Pill) or passively viewed (PV) repulsive and neutral images. The imaginary pill reduced reported disgust more effectively than the OLP pill and was also perceived as a more plausible method to reduce emotional distress. Relative to the OLP pill, the imaginary pill lowered neural activity in a region of interest involved in disgust processing: the pallidum. No significant differences in brain activation were found when comparing the OLP pill with PV. These findings highlight that imagining the intake of an OLP emerged as a superior method for regulating feelings of disgust compared to the actual ingestion of a placebo pill. The study's innovative approach sheds new light on the potential of placebo interventions in emotion regulation.

Brain mechanisms for processing caress-like touch in skin-picking disorder.

Skin-picking disorder (SPD) is characterized by repetitive touching and picking of one's skin. The picking is typically experienced as pleasant although this behavior leads to tissue damage. The present functional magnetic resonance imaging (fMRI) study investigated how individuals with SPD react to caress-like touch, which stimulates C-tactile afferents. A standardized touch procedure was used. Seventy females with a primary diagnosis of SPD and 62 healthy females received CT-optimal brushing of their forearms (3 cm/s) and non-optimal brushing (30 cm/s) during an fMRI session. The two types of tactile stimulation were rated according to pleasure, arousal, and urge to pick one's skin. Relative to healthy controls, patients with SPD showed greater activation in parietal regions (supramarginal/angular gyrus) during CT-optimal touch. Moreover, the deactivation of the middle/ inferior frontal cortex displayed by control participants was absent in the SPD group. Being touched was rated as less pleasant, more arousing, and elicited a greater urge to perform skin-picking in participants with SPD. The mentioned frontal and parietal brain regions are sources of attentional control. They are involved in integrating somatosensory information and switching attention between external/internal stimuli. The present study adds to the limited database on the dysfunctional processing of touch in SPD. This study was preregistered on the German Clinical Trials Register (DRKS00022123, June 8th, 2020).

Atypical cerebellar activity and connectivity during affective touch in adults with skin-picking disorder.

Excessive touching and picking of one's skin are core symptoms of skin-picking disorder (SPD). Previous research has shown that patients with SPD display difficulties in motor control and show altered reward responsivity. Considering the limited knowledge about neuronal mechanisms in SPD, particularly concerning the cerebellum, the analysis focused on this brain region due to its involvement in sensorimotor and affective functions. The participants of the present study received affective (caress-like), which is typically perceived as pleasant and can be passively enjoyed. A total of 132 female participants (70 patients with SPD, 62 healthy controls) received affective and nonaffective touch to their forearms (slow vs. fast brushing) during functional magnetic resonance imaging. This tactile stimulation was rated according to pleasure, arousal, and the urge to pick one's skin. Being touched was perceived as more negative and arousing by the SPD group, and elicited a greater urge to perform skin-picking. During affective touch, those participants with SPD were characterized by reduced activity in lobule VIII, reduced functional connectivity of lobule VIII with the hippocampus, and increased connectivity with the superior parietal lobule. Since VIII is involved in the inhibition of movement, the present findings point to deficient motor control in SPD in the context of affective-sensory processing.

A differentiated look at emotions: association between gaze behaviour during the processing of affective videos and emotional granularity.

The ability to distinguish between subtle differences among emotions of similar valence is labelled emotion differentiation (ED). Previous research has demonstrated that people high in ED are less likely to use disengagement regulation strategies (i.e. avoidance/distraction) during negative affective states.The present eye-tracking study examined associations between ED and visual attention/avoidance of affective stimuli. A total of 160 participants viewed emotional video clips (positive/ negative), which were concurrently presented with a non-affective distractor image. After each video, participants verbally described their experienced emotions with adjectives in an open-response format. Moreover, they completed an ED questionnaire.The computed ED specificity index for the negative videos (the number of specific adjectives divided by all adjectives used) was positively associated with the scores on the ED questionnaire and visual revisits for the negative videos (how many times the participants gazed back and forth between video and distractor). This viewing style might reflect more active exploratory behaviour directed toward acquiring information about the negative stimulus and its context. The ED measures were not associated with the gaze behaviour for positive videos.

A randomized trial that compared brain activity, efficacy and plausibility of open-label placebo treatment and cognitive repappraisal for reducing emotional distress.

Placebo pills can reduce emotional distress even when recipients have been informed about the inert nature of the treatment. However, before such open-label placebos (OLPs) can be recommended for general clinical use, their efficacy and acceptability need to be further investigated and compared with established methods for emotion regulation, such as cognitive reappraisal (CR). The current study with functional magnetic resonance imaging compared the effects of an OLP pill with CR for reducing a specific form of emotional distress: disgust. Participants (150 healthy females) were randomly allocated to one of three groups, all of which were exposed to disgusting and neutral images (OLP, CR, PV: passive viewing). It was tested whether the three groups would differ in brain activity and reported disgust. Ratings for the perceived efficacy and plausibility of treatment were also compared between OLP and CR. Both OLP and CR increased the activity in a cognitive control region, the ventrolateral prefrontal cortex. Relative to PV and OLP, CR reduced activity in the putamen and pallidum. These regions play an important role in decoding disgust signals from different modalities. Self-reports indicated that CR was perceived as a more effective and plausible intervention strategy than OLP. In conclusion, CR was a superior method for disgust regulation compared to OLP, both on the subjective as well as the neurobiological level. Future OLP studies are needed to test whether the observed effects generalize to other forms of emotional distress.

A neurobiological evaluation of soft touch training for patients with skin-picking disorder.

BACKGROUND: Individuals with skin-picking disorder (SPD) display reduced neural sensitivity to slow/soft touch. This functional magnetic resonance imaging (fMRI) study investigated the effects of Soft Touch Training (STT) on neural correlates of touch processing and SPD symptoms. METHOD: Females with a primary diagnosis of SPD (n = 57) were randomly assigned to receive either four weeks of STT (guided soft brushing of selected skin regions) or Progressive Muscle Relaxation (PMR) training (guided tensing and relaxing of selected muscle regions). The app-assisted intervention consisted of 15-minute daily training sessions at home. Before and after the four-week intervention, the two groups participated in a standardized tactile stimulation procedure during fMRI (affective vs nonaffective touch of the forearm). Intervention-based changes in subjective and neural responses to the tactile stimulation as well as SPD severity were compared between the groups. RESULTS: STT increased the pleasantness ratings for (affective) touch administered during fMRI, which was accompanied by decreased activation in the parietal operculum (PO) and supramarginal gyrus (SMG), as well as increased PO-SMG connectivity. These findings possibly reflect normalized affective touch processing due to STT. Both interventions (STT and PMR) reduced SPD severity. CONCLUSIONS: This study demonstrated that a brief app-assisted touch training can change the experience of receiving touch from others and the associated brain activity and connectivity. Adaptations of the training relating to duration/ frequency of sessions might enhance its effectiveness.

Discriminative and Affective Processing of Touch: Associations with Severity of Skin-picking.

Skin-picking is a common behavior in the general population that generally serves emotion regulation (e.g., reduction of tension). However, recent research suggests it may also be associated with changes in tactile processing sensitivity. Along these lines, the present study examined whether the severity of skin-picking (SOSP) is related to discriminative and affective touch processing. A total of 160 participants (59 males, 101 females, mean age = 31 years) completed two tactile discrimination tests (two-point discrimination, surface texture discrimination), as well as a well-validated affective touch paradigm (delivery of soft/slow touch, which is found to be generally pleasant). A hierarchical regression analysis was carried out to investigate the association between SOSP, age, sex, and indicators of tactile sensitivity. Replicating previous findings, females reported higher SOSP. While the performance in the discrimination tests did not predict SOSP, affective touch processing was associated with SOSP. Participants with high SOSP reported an urge to pick their skin after being softly touched. This seems paradoxical since previous findings have suggested skin-picking may be carried out to manage negative affective states. Our findings add to the literature describing altered sensitivity and responsivity to specific tactile stimuli in individuals with excessive skin-picking.

Self-disgust in Patients with Dermatological Diseases.

BACKGROUND: Dermatological diseases can be associated with symptoms such as oozing pus, weeping, and/or bleeding, which represent primary disgust elicitors. This study examined the role of self-disgust in people with different skin conditions (e.g., hidradenitis suppurativa, psoriasis, lichen sclerosus). METHODS: A self-selected sample of 200 dermatology patients completed questionnaires for the assessment of self-disgust, experienced stigmatization, symptoms of depression, anxiety, and somatization. Multiple regression analysis and mediation analysis were computed to examine the relationship between self-disgust and the other selected variables. RESULTS: Sixty-four percent of the patients reported elevated self-disgust. Sex, age, depression, and perceived stigmatization were predictors of self-disgust. Depression mediated the relationship between stigmatization (e.g., staring by others) and self-disgust. CONCLUSIONS: This study points to the important role of self-disgust in dermatological conditions. Public health programs to counteract stigmatization of patients with skin diseases as well as therapy approaches that help decrease patients' self-disgust and increase self-acceptance are urgently needed.

The association between local brain structure and disgust propensity.

Research has discovered structural differences in the brains of people with different personality types. In the present voxel-based morphometry study we focused on the association between disgust propensity (DP: the temporally stable tendency to experience disgust across different situations) and grey matter volume (GMV) in regions of interest [insula, orbitofrontal cortex (OFC), basal ganglia]. We collected structural brain scans from 498 healthy individuals (352 females, 146 males; mean age = 27 years). Regression analyses were performed to test the association between three domains of DP (core, animal-reminder, contamination) and GMV. We observed negative correlations between animal-reminder DP and the volume of the insula, and contamination DP and OFC volume. Animal-reminder DP correlated positively with GMV in the basal ganglia (putamen). This study identified weak correlations between local brain volume and disgust propensity. The association between DP and insula volume concerned the posterior insula and was in the opposite of the expected direction. The findings of this study are inconsistent with the concept of the anterior insula as a region that specifically mediates DP.

The association between the belief in coronavirus conspiracy theories, miracles, and the susceptibility to conjunction fallacy.

Previous research has shown that people who endorse conspiracy theories are more prone to the conjunction fallacy: the tendency to perceive conjunct events as more probable than constituent events. The present study examined the relationship between specific beliefs (belief in conspiracy theories, religiosity) and the susceptibility to conjunction errors (CEs) in specific domains. A total of 500 participants was presented with brief scenarios from the domains "coronavirus conspiracy," "miraculous healing," and a control condition. Each scenario included one statement about a separate event and a second statement about two joint events co-occurring. The participants estimated the probability of each statement. Results showed that the number of CEs made in the coronavirus domain was only associated with the belief in conspiracy theories, while general religiosity was only associated with CEs for scenarios describing miraculous healings. The assessed beliefs were not associated with CEs made in the control condition. Results suggest that distinct beliefs are uniquely associated with the susceptibility to conjunction errors in particular domains.

Placebo Effects in the Context of Religious Beliefs and Practices: A Resting-State Functional Connectivity Study.

Background: Placebos (inert substances or procedures) can positively influence a person's psychological and physical well-being, which is accompanied by specific changes in brain activity. There are many different types of placebos with different effects on health-related variables. This study investigated placebo effects in the context of religious beliefs and practices. The participants received an inert substance (tap water) along with the verbal suggestion that the water would come from the sanctuary in Lourdes (a major Catholic pilgrimage site with reports of miracle cures). We investigated changes in resting-state functional connectivity (rsFC) in three brain networks (default-mode, salience, cognitive control) associated with the drinking of the placebo water. Methods: A total of 37 females with the belief that water from the sanctuary in Lourdes has positive effects on their spiritual, emotional, and physical well-being participated in this placebo study with two sessions. The participants drank tap water that was labeled "Lourdes water" (placebo) before a 15-min resting-state scan in one session. In the other (control) session, they received tap water labeled as tap water. The participants rated their affective state (valence, arousal) during the session and were interviewed concerning specific thoughts, feelings, and bodily sensations directly after each of the two sessions. Results: The placebo reduced rsFC in the frontoparietal cognitive control network and increased rsFC in the salience network (insular-cerebellar connectivity). During the session, the participants rated their affective state as very pleasant and calm. The ratings did not differ between the two conditions. Immediately after the session, the participants reported increased intensity of pleasant bodily sensations (e.g., feelings of warmth, tingling) and feelings (e.g., gratefulness) for the "Lourdes water" condition. Conclusions: The present findings provide the first evidence that placebos in the context of religious beliefs and practices can change the experience of emotional salience and cognitive control which is accompanied by connectivity changes in the associated brain networks.

The association between the propensity to experience meaningful coincidence and brain anatomy in healthy females: The moderating role of coping skills.

When two events co-occur within a specific time interval, some people experience 'meaningful coincidence'. This may be a consequence of the mind searching for causal structure in reality. In cases of negative events, it may be a coping strategy for managing stress. The present voxel-based morphometry (VBM) study investigated neural correlates of the propensity to experience meaningful coincidence (PEMC). VBM data from 115 females (mean age: 26 years) were correlated with self-reported PEMC and the use of certain coping strategies (e.g. seeking support, positive focusing). PEMC was negatively correlated with grey matter volume (GMV) in the medial prefrontal cortex, the inferior frontal gyrus, and the superior/inferior parietal cortex. Moderation analyses indicated that the negative association between GMV in the mentioned brain regions and PEMC was only present in participants with average or below-average coping skills. The identified fronto-parietal regions are part of an integrated neural network implicated in the detection of causality and cognitive control.

The processing of visual food cues during bitter aftertaste perception in females with high vs. low disgust propensity: an fMRI study.

An extremely bitter taste can signal food spoilage, and therefore typically elicits disgust. The present cross-modal functional magnetic resonance imaging experiment investigated whether the personality trait 'disgust propensity' (DP; temporally stable tendency to experience disgust across different situations) has an influence on the processing of visual food cues during bitter aftertaste perception. Thirty females with high DP and 30 females with low DP viewed images depicting sweet food (e.g., cakes, ice cream) and vegetables, once in combination with an extremely bitter aftertaste (concentrated wormwood tea), and once with a neutral taste (water). Females highly prone to disgust (compared to low disgust-prone females) showed increased activity in the anterior cingulate cortex (ACC) and increased mPFC-insula connectivity when presented with the mismatch of a bitter aftertaste and visual cues of sweet food. The ACC is involved in conflict monitoring and is strongly interconnected with insular areas. This connection plays a critical role in awareness of changes in homeostatic states. Our findings indicate that the personality trait DP is associated with cross-modal integration processes of disgust-relevant information. Females high in DP were more alert to food-related sensory mismatch (pleasant visual features, aversive taste) than females low in DP.

Enjoyment of watching pimple popping videos: An fMRI investigation.

BACKGROUND: Millions of people enjoy watching videos of pimple treatments. The underlying neural mechanisms of this enjoyment have not been investigated so far. METHOD: We administered a total of 96 video clips from three categories: Pimple Popping (PP), Water Fountains (WF), and Steam Cleaning (SC). The PP videos showed a pimple or blackhead that was opened to squeeze out the pus or sebum. The female participants (mean age: 24 years) were assigned to one of two groups: females who reported to enjoy watching PP (PPE_high; n = 38) and those with little enjoyment (PPE_low; n = 42). We analyzed brain activity in regions of interest (ROI) involved in the encoding of pleasure and aversion (e.g., nucleus accumbens (NAc), insula). RESULTS: The PPE_high group showed less deactivation of the NAc (ROI finding), more frontopolar activation (whole-brain finding), and stronger accumbens-insula coupling than the PPE_low group. CONCLUSIONS: A specific pattern of brain activity and connectivity that involves the NAc and insula (coding of aversion/pleasure) and the frontopolar region (prediction of outcomes of motor decisions) is associated with the enjoyment of PP videos.

Comparison of women with high vs. low food addiction tendency: a pilot study with voxel-based morphometry.

BACKGROUND: The concept of 'food addiction' (FA) posits that highly processed food with added fat and/or refined carbohydrates is capable of triggering addictive-like eating behavior. FA may be one possible phenotype in obesity. METHODS: The present voxel-based morphometry (VBM) study compared data from three groups of women. One group scored high on the Yale Food Addiction Scale (YFAS) and was overweight (n = 21), whereas the two other groups had low YFAS scores and were either overweight (n = 21) or normal-weight (n = 21). RESULTS: Overweight women with high YFAS scores had less grey matter volume (GMV) in the inferior frontal gyrus (IFG) than overweight women with low FA tendency, who in turn had less GMV in the IFG than the normal-weight group. The IFG is involved in response inhibition, which is relevant for the control of appetite and food intake. In the group with high FA tendency, the frequency of binge episodes was substantially correlated with the YFAS scores, and 11 women of this group were diagnosed with binge-eating disorder (BED). The association between IFG volume and YFAS scores was not statistically significant anymore when controlling for the effect of binge frequency as revealed by partial correlation analysis. CONCLUSION: This VBM study revealed an association between reported FA tendency and a neural correlate of disinhibited eating. Future studies with bigger sample sizes are needed in order to demonstrate that FA is sufficiently different from existing conditions (e.g., BED) to warrant classification as a distinct disease phenotype.

Neural underpinnings of perception and experience of disgust in individuals with a reduced sense of smell: An fMRI study.

BACKGROUND: Individuals with reduced olfactory function (anosmia, hyposmia) have reported changes in disgust perception and disgust experience compared to normosmic controls. The current functional magnetic resonance imaging (fMRI) study investigated the neural underpinnings of the altered disgust processing. METHOD: Twenty-four patients with anosmia or hyposmia and 26 normosmic controls were presented with images depicting facial expressions and scenes from the categories disgust and neutral. The disgusting scenes depicted stimuli that typically smell repulsive (spoiled food, excrements). Brain activity and structure in the primary olfactory cortex (POC) and in a region that processes affective/motivational olfactory-related information (insula, orbitofrontal cortex, basal ganglia) were compared between the two groups. RESULTS: The anosmic/hyposmic participants were characterized by greater activation in the POC while looking at disgusting scenes. The POC can be activated by olfactory imagery and holds predictive templates of olfactory stimuli. The neural processing of the facial stimuli did not differ between the two groups. Additionally, group differences in functional connectivity and brain structure were not present or only minor. CONCLUSION: The increased POC activation in anosmic/hyposmic patients might reflect a compensatory process that helps to compensate for their olfactory deficit. However, in general, this study identified only small adaptations in the neural disgust system as a consequence of reduced olfactory function.

Belief in the miracles of Lourdes: A voxel-based morphometry study.

BACKGROUND: It has been shown that particular religious beliefs and practices are associated with brain function and structure. The present voxel-based morphometry study investigated the correlation between the belief in the miracles of Lourdes (a major Catholic pilgrimage site) and gray matter volume in specific brain regions associated with theory of mind (ToM). METHOD: Structural brain data from 84 women (mean age: 25 years; no current somatic illness; 80% Roman-Catholic) were correlated with self-report measures on belief in miracles, religious-spiritual well-being, and psychological problems. Selected brain regions of the ToM network included the temporoparietal junction (TPJ), hippocampus, amygdala, and medial prefrontal cortex (MPFC). RESULTS: The belief in the miracles of Lourdes was positively correlated with general religiousness and with feelings of connectedness; there was no association with psychological problems. Belief in miracles of Lourdes correlated positively with TPJ volume and negatively with MPFC volume. CONCLUSION: Belief in the miracles was associated with brain volume in regions involved in mentalizing and self-control.

Cerebellar Gray Matter and Olfactory Performance.

The role of the cerebellum in the chemical senses is still poorly understood. This voxel-based morphometry (VBM) study investigated associations between gray matter volume (GMV) in subregions of the cerebellum and olfactory performance. VBM data from 48 men were analyzed. The participants were tested with a standardized olfactory test that measured olfactory threshold, discrimination, and identification ability. The investigated sample covered a wide range of olfactory performance, including individuals with a reduced sense of smell (anosmia and hyposmia) and normosmia. The computed regression analyses revealed a positive association between olfactory identification performance and GMV in lobule VI. This cerebellar subregion is involved in higher-order cognitive functions (language and memory), which are necessary prerequisites for correct odor labeling. Odor detection and discrimination were unrelated to cerebellar GMV.