Transfer of information across repeated decisions in general and in obsessive-compulsive disorder.

Real-life decisions are often repeated. Whether considering taking a job in a new city, or doing something mundane like checking if the stove is off, decisions are frequently revisited even if no new information is available. This mode of behavior takes a particularly pathological form in obsessive-compulsive disorder (OCD), which is marked by individuals' redeliberating previously resolved decisions. Surprisingly, little is known about how information is transferred across decision episodes in such circumstances, and whether and how such transfer varies in OCD. In two experiments, data from a repeated decision-making task and computational modeling revealed that both implicit and explicit memories of previous decisions affected subsequent decisions by biasing the rate of evidence integration. Further, we replicated previous work demonstrating impairments in baseline decision-making as a function of self-reported OCD symptoms, and found that information transfer effects specifically due to implicit memory were reduced, offering computational insight into checking behavior.

Noncanonical cytoplasmic poly(A) polymerases regulate RNA levels, alternative RNA processing, and synaptic plasticity but not hippocampal-dependent behaviours.

Noncanonical poly(A) polymerases are frequently tethered to mRNA 3' untranslated regions and regulate poly(A) tail length and resulting translation. In the brain, one such poly(A) polymerase is Gld2, which is anchored to mRNA by the RNA-binding protein CPEB1 to control local translation at postsynaptic regions. Depletion of CPEB1 or Gld2 from the mouse hippocampus results in a deficit in long-term potentiation (LTP), but only depletion of CPEB1 alters animal behaviour. To test whether a related enzyme, Gld4, compensates for the lack of Gld2, we separately or simultaneously depleted both proteins from hippocampal area CA1 and again found little change in animal behaviour, but observed a deficit in LTP as well as an increase in long-term depression (LTD), two forms of protein synthesis-dependent synaptic plasticity. RNA-seq data from Gld2, Gld4, and Gld2/Gld4-depleted hippocampus show widespread changes in steady state RNA levels, alternative splicing, and alternative poly(A) site selection. Many of the RNAs subject to these alterations encode proteins that mediate synaptic function, suggesting a molecular foundation for impaired synaptic plasticity.

Chest Wall Mobility: Identification of Underlying Predictors.

OBJECTIVE: The purpose of this study was to identify factors contributing to normal mobility or hypermobility of the chest wall. METHODS: Seventy-eight young adults were divided into 2 groups: patients with normal mobility (group 1, n = 40) and hypermobility of the chest wall (group 2, n = 38). The mean mobility of the chest wall in groups 1 and 2 was 9.9 and 6.1 cm, respectively. The mean age of groups 1 and 2 was 22.2 and 21.5 years, respectively. The Brief Symptom Inventory, State-Trait Anxiety Inventory, Beck Depression Inventory, and the Perceived Stress Scale were used to evaluate the psychometric properties. Quality of life was assessed using 12-Item Short Form Health Survey. Smoking status was determined via self-report of current smoking status. Chest wall mobility was measured using thoracic and axillary cirtometry. Pulmonary functions were evaluated using a Spirobank II device. Subsequently, forced vital capacity (FVC), forced expiratory volume in 1 second, peak expiratory flow, and forced expiratory flow 25% to 75% were verified. Carefusion Micro RPM and the 6-minute walk test were used to evaluate maximal respiratory pressures and functional capacity, respectively. RESULTS: With backward linear regression models, FVC and obsessive-compulsive traits were significant predictors of chest wall mobility (R²â€¯= 0.27; P < .001 and P = .01, respectively). In logistic regression models, FVC, maximum inspiratory pressure, and obsessive-compulsive traits were significant predictors of normal mobility/hypermobility of the chest wall (R²â€¯= 0.42; P < .001, P = .01, and P = .03, respectively). CONCLUSION: Forced vital capacity, maximum inspiratory pressure, and obsessive-compulsive traits are significant predictors of chest wall mobility and normal mobility or hypermobility of the chest wall.

Is sustained attention deficit related to subclinical obsessive thoughts in children and adolescents with ADHD?

Background: Thought content and its impact on sustained attention in individuals with attention deficit hyperactivity disorder (ADHD) are topics of growing interest in literature.Objective: We hypothesised that subclinical obsessive thoughts may be correlated with attention lapses in individuals with ADHD.Method: Thirty children diagnosed with ADHD participated in the study and their level of subclinical obsessive thoughts, attention, and executive function were measured using Children Yale-Brown Obsessive Scale and Conners' Continuous Performance Test II.Results: No significant correlation between sustained attention impairment and the level of obsessive thoughts in patients with ADHD was found. Nevertheless, patients with ADHD with subclinical obsessive thoughts showed more commission errors than those without (W = 51.5; p = 0.02).Conclusion: The nature of thought content in individuals with ADHD should be linked to executive dysfunction rather than attentional impairment. This could be of importance in the therapeutic strategy choice, addressing the importance of executive function remediation in the specific context of subclinical obsessive thoughts.Key points Patients with ADHD, without OCD or ASD comorbidity, still present subclinical obsessive thoughts (36% of our sample). • Subclinical obsessive thoughts could be a part of thought content in patients with ADHD. • Subclinical obsessive thoughts as measured by the CPT-II are not correlated with attention function in patients with ADHD. • ADHD patients with subclinical obsessive symptoms present more impairment in response inhibition than the ones without. • Results on subclinical obsessive thoughts are similar to those on another type of thought content called 'mind wandering'. • A clinical improvement strategy for patients with ADHD could be using executive function remediation rather than classical attention function remediation, according to both to our and previous results.

Obsessive-Compulsive Symptoms are Less Common in Huntington's Disease than Reported Earlier.

BACKGROUND: Previous research using the Symptom-Checklist-90-Revised (SCL-90-R) has shown that compulsive symptoms in Huntington's disease (HD) occur in 10% to 52% of all cases. The "Hamburger-Zwangsinventar" (HZI), a self-rating questionnaire comprising 188 items, taps into the domain of compulsiveness in greater detail, but has not been used in HD so far. In addition, little is known about the association of obsessive-compulsive symptoms with pre-clinical stages of HD. OBJECTIVE: Comparison of OC symptoms measured by the SCL-90-R and the HZI in pre-HD and HD. METHODS: 29 premanifest mutation carriers (pre-HD) and 40 manifest HD patients completed both questionnaires. Clinical characteristics of HD were rated by using the UHDRS. RESULTS: Compared to data from general population prevalence of OC symptoms were not higher as expected in preHD and only slightly elevated in manifest HD if using HZI. Both instruments detected more OC symptoms in HD patients compared to pre-HD. The SCL-90-R more often detects compulsivity than the HZI. Results of both questionnaires showed correlations to cognition, depression, and disease duration. Compared to findings from OCD patients, there was a subordinate role in the HZI subscale for "washing and cleaning" in HD. CONCLUSIONS: OC symptoms in pre-HD occur not more often than in general population. The HZI appears to be useful for examining OC symptoms in detail in pre-HD and HD. HZI-subscale ratings for washing and cleaning compulsions were less pronounced in HD compared to OCD patients, possibly due to loss of disgust. The SCL-90-R might overestimate OC symptoms in both groups.

Contribution of left frontal-motor alpha phase synchronization to semantic inhibition in obsessive-compulsive tendencies.

Patients with obsessive-compulsive disorder attempt to suppress obsessions and/or compulsions. Although previous psychological research suggests reduced semantic inhibition in such patients, no research has explored the underlying neural mechanisms of semantic control in patients with obsessive-compulsive disorder. In addition to semantic representation, semantic control also generates task-relevant behaviors. Previous research has implicated the left frontal and posterior temporal areas in semantic control; however, no research approaches the dynamic relationships among task-relevant brain areas. To address this, we investigated the phase synchronizations among these areas using time-frequency analysis of data from an electroencephalograph, recorded during a semantic classification task. Participants were healthy patients whose obsessive-compulsive tendencies were assessed using a questionnaire. In this task, when presented with a red colored word, participants were required to classify it into categories as either plants or animals with a keypress (i.e. the classification condition). When presented with a green colored word, participants were required to read it without classification (i.e. the inhibition condition). The behavioral results showed that the semantic negative priming (i.e. the increase in reaction time to the word included in the previously inhibited category) was negatively correlated with obsessive-compulsive tendencies. Electroencephalograph results showed that the left frontal-motor alpha phase synchronization under the classification condition was significantly higher than under the inhibition condition. This phase synchronization under the inhibition condition was positively correlated with obsessive-compulsive tendencies. These results suggest that a dynamic link between the left frontal and motor areas may reflect reduced semantic inhibition in individuals with stronger obsessive-compulsive tendencies.

Altered anatomical connections of associative and limbic cortico-basal-ganglia circuits in obsessive-compulsive disorder.

BACKGROUND: Current neurocognitive models suppose dysfunctions of associative and limbic cortico-basal ganglia circuits to be at the core of obsessive-compulsive disorder (OCD). As little is known about the state of underlying anatomical connections, we investigated whether these connections were reduced and/or not properly organised in OCD patients compared to control. METHODS: Diffusion magnetic resonance images were obtained in 37 OCD patients with predominant checking symptoms and 37 matched healthy controls. We developed indices to characterise the quantity (spatial extent and density) and the organisation (topography and segregation) of 24 anatomical connections between associative and limbic cortical (anterior cingulate, dorsolateral prefrontal, orbitofrontal cortices and the frontal pole), and subcortical (caudate nucleus, putamen and thalamus) areas in each hemisphere. RESULTS: Associative and limbic cortico-basal-ganglia connections were reduced in OCD patients compared to controls: 19/24 connections had a reduced subcortical spatial extent, 9/24 had a reduced density. Moreover, while the general topography was conserved, the different cortical projection fields in the striatum and thalamus were hyper-segregated in OCD patients compared to controls. CONCLUSION: These quantitative and qualitative differences of anatomical connections go beyond the current model of a reduced cortical control of automatic behaviour stored in the basal ganglia. The hyper-segregation in OCD could also impair the integration of cortical information in the thalamus and striatum and distort the subsequent behavioural selection process. This provides new working hypotheses for functional and behavioural studies on OCD.

OCD-like behavior is caused by dysfunction of thalamo-amygdala circuits and upregulated TrkB/ERK-MAPK signaling as a result of SPRED2 deficiency.

Obsessive-compulsive disorder (OCD) is a common neuropsychiatric disease affecting about 2% of the general population. It is characterized by persistent intrusive thoughts and repetitive ritualized behaviors. While gene variations, malfunction of cortico-striato-thalamo-cortical (CSTC) circuits, and dysregulated synaptic transmission have been implicated in the pathogenesis of OCD, the underlying mechanisms remain largely unknown. Here we show that OCD-like behavior in mice is caused by deficiency of SPRED2, a protein expressed in various brain regions and a potent inhibitor of Ras/ERK-MAPK signaling. Excessive self-grooming, reflecting OCD-like behavior in rodents, resulted in facial skin lesions in SPRED2 knockout (KO) mice. This was alleviated by treatment with the selective serotonin reuptake inhibitor fluoxetine. In addition to the previously suggested involvement of cortico-striatal circuits, electrophysiological measurements revealed altered transmission at thalamo-amygdala synapses and morphological differences in lateral amygdala neurons of SPRED2 KO mice. Changes in synaptic function were accompanied by dysregulated expression of various pre- and postsynaptic proteins in the amygdala. This was a result of altered gene transcription and triggered upstream by upregulated tropomyosin receptor kinase B (TrkB)/ERK-MAPK signaling in the amygdala of SPRED2 KO mice. Pathway overactivation was mediated by increased activity of TrkB, Ras, and ERK as a specific result of SPRED2 deficiency and not elicited by elevated brain-derived neurotrophic factor levels. Using the MEK inhibitor selumetinib, we suppressed TrkB/ERK-MAPK pathway activity in vivo and reduced OCD-like grooming in SPRED2 KO mice. Altogether, this study identifies SPRED2 as a promising new regulator, TrkB/ERK-MAPK signaling as a novel mediating mechanism, and thalamo-amygdala synapses as critical circuitry involved in the pathogenesis of OCD.

Factor analysis of symptom dimensions (psychotic, affective and obsessive compulsive symptoms) in schizophrenia.

AIM: To carryout factor analysis of symptom profile of patients with schizophrenia assessed by using positive and negative syndrome scale (PANSS), Calgary depression rating scale (CDSS), Young mania rating scale (YMRS) and YBOCS checklist. METHODOLOGY: 181 patients of schizophrenia were assessed on PANSS, CDSS, YMRS and YBOCS checklist. RESULTS: Factor analysis of PANSS yielded 3 factor structure (positive, negative, anxiety). When the items of CDSS were added to the PANSS items, total number of factors increased to 4 with depression emerging as a separate factor. Addition of YMRS to PANSS and CDSS led to emergence of 5 factor model. Further addition of YBOCS checklist led to emergence of a 7 factor model (positive, depressive, obsessive compulsive, negative, manic, anxiety and obsessive compulsive-2), which explained 49.85% variance of the data. Positive symptoms emerged as the factor-1. Depressive symptoms loaded on the factor-2, negative symptoms loaded on to factor-4, manic symptoms loaded onto factor-5 and anxiety symptoms loaded onto factor-6. OC symptoms loaded onto factor 3 and 7. CONCLUSIONS: Present study suggests that when multiple scales are used for assessment of various symptoms of schizophrenia, the symptoms separate out into 7 factors. This finding suggests that clinical assessment of schizophrenia should not be limited to core psychotic symptoms only and structured instruments must be used to elicit other symptoms too while monitoring the clinical picture of patients with schizophrenia.

Alterations of gray and white matter morphology in obsessive compulsive disorder.

BACKGROUND: While the ethio-pathogenesis of Obsessive-Compulsive disorder (OCD) remains unknown, there is increased evidence of widespread structural alterations in both white and gray matter in OCD patients that include, but are not restricted, to abnormalities in cortico-striatal-thalamo-cortical (CSTC) regions. The objective of this study was to test the existence of structural alterations in both white and gray matter in a sample of OCD patients when compared with a group of non-clinical matched controls (NCC), using voxel-based morphometry (VBM). METHOD: Fifteen patients with OCD and 15 NCC underwent MRI structural scanning. RESULTS: Frontal (increased gray matter in the middle frontal gyrus) and subcortical regions (increased white matter in the pallidum) were found to be affected in patients. Additionally, temporal-parietal regions were also found to be affected and highly correlated with OCD symptom severity (decrease of gray matter in the superior parietal lobe and white matter in the angular and superior temporal gyri). CONCLUSIONS: These alterations may be associated with prominent OCD symptoms, such as difficulties with inhibitory control (pallidum, angular gyrus), executive functioning (middle frontal gyris), compulsive checking (superior temporal gyrus) and visual-spatial deficits (superior parietal lobe).

Anodal tDCS over the right dorsolateral prefrontal cortex modulates cognitive processing of emotional information as a function of trait rumination in healthy volunteers.

Healthy individuals reporting higher (as compared to lower) levels of trait rumination recruit more neural activity in dorso-cortical regions (mostly in the right hemisphere) when inhibiting negative information, possibly to compensate their difficulty to disengage from it. In the present study, we investigated whether these latter neural correlates are causally implicated in cognitive control in these individuals. We administered the Cued Emotional Control Task, a measure of cognitive control indexed by cognitive costs for inhibiting versus providing a habitual response for emotional information, in thirty-five healthy volunteers reporting a broad range of trait rumination levels. Participants completed the task after receiving both real and sham-placebo (counterbalanced order) anodal transcranial Direct Current Stimulation (tDCS) over the right dorsolateral prefrontal cortex (DLPFC). Results reveal that the tDCS induced effects on cognitive costs for emotional information were associated with individual differences in trait rumination: the higher the trait rumination level, the less cognitive costs following real neuromodulation of the right DLPFC. Interestingly, these effects were observed for both positive and negative stimuli, and not only negative information as hypothesized. Overall, the data suggest that the right DLPFC is causally involved in the alteration of cognitive control in healthy individuals who tend to ruminate, possibly by helping them to disengage from emotional material.

Relationship between impulsivity and obsession types in obsessive-compulsive disorder.

OBJECTIVE: Impulsivity is an important aspect of obsessive-compulsive disorder (OCD) which is classified under a new heading in DSM-5 with other impulsivity related disorders like trichotillomania. Due to its heterogeneous nature, different obsessions may be linked to varying impulsivity profiles. Aim of this study was to investigate the impulsivity traits and their relationship with obsession types by comparing OCD subjects who display sexual, religious and aggressive obsessions or other obsessions to healthy controls. METHODS: Outpatients with OCD (n = 146) and healthy controls (n = 80) were evaluated with Sociodemographic Data Form, SCID-I, SCID non-patient version, Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and Barratt Impulsiveness Scale (BIS-11). RESULTS: BIS-11 attention scores of the OCD group were significantly higher than healthy subjects. In patients with sexual, aggressive, religious obsessions, BIS-11 attention scores were significantly higher than those who have other obsession types and that of controls. CONCLUSIONS: Higher levels of attentional impulsivity, particularly in patients suffering from sexual, aggressive or religious obsessions suggest a common diathesis for a dysfunction in neural correlates corresponding to these symptoms. The results of our study may promote further studies conducted with more advanced and objective neuropsychometric tests evaluating features of the clinical course, neurobiology and the response to OCD treatment.

Executive dysfunction, obsessive-compulsive symptoms, and attention deficit and hyperactivity disorder in Systemic Lupus Erythematosus: Evidence for basal ganglia dysfunction?

INTRODUCTION: Chorea is well described in a group of patients with Systemic Lupus Erythematosus (SLE). There is less information, however, on other movement disorders as well as non-motor neuropsychiatric features such as obsessive-compulsive symptoms (OCS), executive dysfunction and attention deficit and hyperactivity disorder (ADHD) in subjects with SLE. METHODS: Fifty-four subjects with SLE underwent a battery of neuropsychiatric tests that included the Mini Mental State Examination, the Montreal Cognitive Assessment, the Frontal Assessment Battery (FAB), the FAS verbal and the categorical (animals) semantic fluency tests, the Obsessive and Compulsive Inventory - Revised, the Yale-Brown Obsessive and Compulsive Scale and Beck's Anxiety and Depression Scales. ADHD was diagnosed according to DSM-IV criteria. SLE disease activity and cumulative damage were evaluated according to the modified SLE Disease Activity Index 2000 (mSLEDAI-2K) and the SLICC/ACR, respectively. RESULTS: Six (11.1%) and 33 (61.1%) patients had cognitive impairment according to the MMSE and MoCA, respectively. Eleven (20.4%) had abnormal FAB scores, and 5 (9.3%) had lower semantic fluency scores than expected. The overall frequency of cognitive dysfunction was 72.2% (39 patients) and of neuropsychiatric SLE was 77.8% (42 patients). Two patients (3.7%) had movement disorders. Fifteen (27.8%) had OCS and 17 (31.5%) met diagnostic criteria for ADHD. ADHD and OCS correlated with higher disease activity, p=0.003 and 0.006, respectively. Higher cumulative damage correlated with lower FAB scores (p 0.026). CONCLUSIONS: Executive dysfunction, ADHD, OCS, and movement disorders are common in SLE. Our finding suggests that there is frequent basal ganglia dysfunction in SLE.

The impact of obsessive dimension on symptoms and functioning in schizophrenia.

Obsessive Compulsive Symptoms (OCS) and Disorder (OCD) occur frequently in patients with schizophrenia. Nevertheless the impact of OCS/OCD on clinical characteristics and outcome of schizophrenia remains controversial. The aim of the present study is to examine the effect of obsessive-compulsive dimension on symptom expression and functioning in schizophrenia. Sixty patients affected by schizophrenia completed the SCID-IV, the Positive and Negative Syndrome Scale, the Yale-Brown Obsessive-Compulsive Scale, the Social and Occupational Functioning Assessment Scale and the Strauss and Carpenter Level of Functioning Rating Scale. Obsessive-compulsive dimension was associated neither with positive or disorganization symptoms nor with negative symptoms. By contrast, it adversely affected levels of functioning, with a major impact exerted by compulsions rather than obsessions. Obsessive-compulsive dimension appears to be independent from negative and positive symptoms of schizophrenia and independently decreases social functioning.

Is impaired response inhibition independent of symptom dimensions in obsessive-compulsive disorder? Evidence from ERPs.

Impaired response inhibition has been consistently reported in patients diagnosed with obsessive-compulsive disorder (OCD). This clinically heterogeneous disorder is characterized by several symptom dimensions that may have distinct, but partially overlapping, neural correlates. The present study examined whether alterations in response inhibition may be related to symptom severity and symptom dimensions. Event-related potentials (ERPs) were recorded in a group of 42 medication-free OCD patients as well as 42 healthy controls during a stop-signal task. Symptom dimension scores were obtained using the Yale-Brown Obsessive Compulsive Scale symptom checklist. OCD patients showed longer stop-signal reaction times (SSRT, p < 0.01) and larger stop-N2 amplitudes (p < 0.01) compared to healthy controls. Neither the longer SSRT nor the larger stop-N2 scores were significantly correlated with symptom severity or present or lifetime OCD symptoms in OCD patients. These results indicate that deficient response inhibition is a common occurrence in OCD patients that is independent of global symptom severity and symptom dimensions. These data support the notion that impaired response inhibition may be a general attribute of patients with OCD.

A maternally inherited 16p13.11-p12.3 duplication concomitant with a de novo SOX5 deletion in a male patient with global developmental delay, disruptive and obsessive behaviors and minor dysmorphic features.

We detail here the clinical description and the family genetic study of a male patient with global developmental delay, disruptive and obsessive behaviors and minor dysmorphic features and a combination of two rare genetic variants: a maternally inherited 16p13.11-p12.3 duplication and a de novo 12p12.1 deletion affecting SOX5. The 16p13.11 microduplication has been implicated in several neurodevelopmental and behavioral disorders and is characterized by variable expressivity and incomplete penetrance. The causes of this variation in phenotypic expression are not fully clear, representing a challenge in genetic diagnosis and counseling. However, several authors have proposed the two-hit model as one of the underlying mechanisms for this phenotypic heterogeneity. Our data could also support this two-hit model in which the 16p13.11-p12.3 duplication might contribute to the phenotype, not only as a single event but also in association with the SOX5 deletion. The SOX5 gene plays important roles in various developmental processes and has been associated with several neurodevelopmental disorders, mainly intellectual disability, developmental delay and language and/or speech delay as well as with behavior problems and dysmorphic features. However, many of the physical features and behavioral manifestations as well as language deficiencies present in our patient are consistent with those previously reported for SOX5 deletions. Patients carrying multiple genomic variants, as the one presented here, illustrate the difficulty in analyzing genotypes when the contribution of each variant results in overlapping phenotypes and/or, alternatively, in the modification of the clinical manifestations defined by the coexisting variant.

Increased orbitofrontal cortex activation associated with "pro-obsessive" antipsychotic treatment in patients with schizophrenia.

BACKGROUND: Patients with schizophrenia have an approximately 10-fold higher risk for obsessive-compulsive symptoms (OCS) than the general population. A large subgroup seems to experience OCS as a consequence of second-generation antipsychotic agents (SGA), such as clozapine. So far little is known about underlying neural mechanisms. METHODS: To investigate the role of SGA treatment on neural processing related to OCS in patients with schizophrenia, we stratified patients according to their monotherapy into 2 groups (group I: clozapine or olanzapine; group II: amisulpride or aripiprazole). We used an fMRI approach, applying a go/no-go task assessing inhibitory control and an n-back task measuring working memory. RESULTS: We enrolled 21 patients in group I and 19 patients in group II. Groups did not differ regarding age, sex, education or severity of psychotic symptoms. Frequency and severity of OCS were significantly higher in group I and were associated with pronounced deficits in specific cognitive abilities. Whereas brain activation patterns did not differ during working memory, group I showed significantly increased activation in the orbitofrontal cortex (OFC) during response inhibition. Alterations in OFC activation were associated with the severity of obsessions and mediated the association between SGA treatment and co-occurring OCS on a trend level. LIMITATIONS: The main limitation of this study is its cross-sectional design. CONCLUSION: To our knowledge, this is the first imaging study conducted to elucidate SGA effects on neural systems related to OCS. We propose that alterations in brain functioning reflect a pathogenic mechanism in the development of SGA-induced OCS in patients with schizophrenia. Longitudinal studies and randomized interventions are needed to prove the suggested causal interrelations.

Neural substrates of rumination tendency in non-depressed individuals.

The tendency to ruminate, experienced by both healthy individuals and depressed patients, can be quantified by the Ruminative Response Scale (RRS). We hypothesized that brain activity associated with rumination tendency might not only occur at rest but also persist to some degree during a cognitive task. We correlated RRS with whole-brain fMRI data of 20 healthy subjects during rest and during a face categorization task with different levels of cognitive demands (easy or difficult conditions). Our results reveal that the more subjects tend to ruminate, the more they activate the left entorhinal region, both at rest and during the easy task condition, under low attentional demands. Conversely, lower tendency to ruminate correlates with greater activation of visual cortex during rest and activation of insula during the easy task condition. These results indicate a particular neural marker of the tendency to ruminate, corresponding to increased spontaneous activity in memory-related areas, presumably reflecting more internally driven trains of thoughts even during a concomitant task. Conversely, people who are not prone to ruminate show more externally driven activity.

Perceptual properties of obsessive thoughts are associated with low insight in obsessive-compulsive disorder.

Obsessions are traditionally defined as bothersome and repetitive thoughts that the patient is unable to resist. Preliminary evidence suggests that in a subgroup of patients with obsessive-compulsive disorder (OCD), obsessions are experienced as partially perceptual. The present study explored the frequency of perceptually laden obsessions and their relationship with illness insight and depression. Twenty-six patients with OCD were administered the newly developed Sensory Properties of Obsessions Questionnaire. Participants were asked to endorse on a 5-point Likert scale whether their obsessions were associated with perceptual features. Participants showed moderate symptom severity. A total of 73% affirmed that their obsessions contained perceptual features. The predominant perceptual channels were visual, tactile, and somatic (i.e., bodily sensations). The extent of perceptual aspects associated with obsessions was strongly correlated with lack of insight (Yale-Brown Obsessive-Compulsive Scale item 11) but not depression severity. The present study suggests that obsessive thoughts are frequently accompanied by perceptual sensations, which concurs with models assuming a continuum between hallucinations and intrusions. Apparently, the more "real" or authentic the obsessive thought is experienced, the less the afflicted person is able to dismiss its content as fully irrational or absurd.