Altered neural circuit for working memory before and after symptom provocation in patients with obsessive-compulsive disorder

Polygenic risk for obsessive-compulsive disorder (OCD) predicts brain response during working memory task in OCD, unaffected relatives, and healthy controls

Alterations in frontal and parietal neural activations during working memory task performance have been suggested as a candidate endophenotype of obsessive-compulsive disorder (OCD) in studies involving first-degree relatives. However, the direct link between genetic risk for OCD and neuro-functional alterations during working memory performance has not been investigated to date. Thus, the aim of the current functional magnetic resonance imaging (fMRI) study was to test the direct association between polygenic risk for OCD and neural activity during the performance of a numeric n-back task with four working memory load conditions in 128 participants, including patients with OCD, unaffected first-degree relatives of OCD patients, and healthy controls. Behavioral results show a significant performance deficit at high working memory load in both patients with OCD and first-degree relatives (p < 0.05). A whole-brain analysis of the fMRI data indicated decreased neural activity in bilateral inferior parietal lobule and dorsolateral prefrontal cortex in both patients and relatives. Most importantly, OCD polygenic risk scores predicted neural activity in orbitofrontal cortex. Results indicate that genetic risk for OCD can partly explain alterations in brain response during working memory performance, supporting the notion of a neuro-functional endophenotype for OCD.

Intrinsic brain abnormalities in drug-naive patients with obsessive-compulsive disorder: A resting-state functional MRI study

BACKGROUND

Using the resting-state functional magnetic resonance imaging (rs-fMRI) in a relatively large sample of drug-naive patients with obsessive-compulsive disorder (OCD), the current study aims to explore alterations in regional and network-level neural function and to determine the association between these alterations in intrinsic neural activity and symptom severity in OCD.

METHODS

A total of 68 drug-naive OCD patients and 68 healthy control subjects (HCS) were examined using rs-fMRI. Regional cerebral function was evaluated by measuring the fraction of amplitude of low-frequency fluctuation (fALFF). Regions with fALFF alterations were used as seeds in whole-brain functional connectivity (FC) analysis. Statistical analyses of fALFF and FC differences between OCD patients with HCS were performed voxel-by-voxel using a two-sample t-test in Statistical Parametric Mapping version 8 (SPM8). Whole brain correlation analyses were performed to identify the association between functional neural correlates and OCD symptom severity evaluated using Yale-Brown Obsessive Compulsive scale (Y-BOCS) and subscale scores.

RESULTS

Relative to HCS, OCD patients showed higher fALFF in the right putamen and right superior frontal gyrus (P < 0.05, corrected for AlphaSim); higher FC in the limbic-striatal circuit and lower FC in the fronto-temporal and fronto-striato-thalamic networks (P < 0.05, corrected for AlphaSim). FC in striato-thalamic junction was negatively correlated with the Y-BOCS total score (r = -0.493, P < 0.001).

CONCLUSION

These findings of focal spontaneous hyperfunction confirmed the prevailing frontal-striatal model of OCD, and altered brain connectivity in large-scale resting-state networks indicated a connectivity-based pathophysiological process in OCD.

Aberrant Dynamic Connectivity for Fear Processing in Anorexia Nervosa and Body Dysmorphic Disorder

Anorexia nervosa (AN) and body dysmorphic disorder (BDD) share distorted perceptions of appearance with extreme negative emotion, yet the neural phenotypes of emotion processing remain underexplored in them, and they have never been directly compared. We sought to determine if shared and disorder-specific fronto-limbic connectivity patterns characterize these disorders. FMRI data was obtained from three unmedicated groups: BDD (n = 32), weight-restored AN (n = 25), and healthy controls (HC; n = 37), while they viewed fearful faces and rated their own degree of fearfulness in response. We performed dynamic effective connectivity modeling with medial prefrontal cortex (mPFC), rostral anterior cingulate cortex (rACC), and amygdala as regions-of-interest (ROI), and assessed associations between connectivity and clinical variables. HCs exhibited significant within-group bidirectional mPFC-amygdala connectivity, which increased across the blocks, whereas BDD participants exhibited only significant mPFC-to-amygdala connectivity (P < 0.05, family-wise error corrected). In contrast, participants with AN lacked significant prefrontal-amygdala connectivity in either direction. AN showed significantly weaker mPFC-to-amygdala connectivity compared to HCs (P = 0.0015) and BDD (P = 0.0050). The mPFC-to-amygdala connectivity was associated with greater subjective fear ratings (R2 = 0.11, P = 0.0016), eating disorder symptoms (R2 = 0.33, P = 0.0029), and anxiety (R2 = 0.29, P = 0.0055) intensity scores. Our findings, which suggest a complex nosological relationship, have implications for understanding emotion regulation circuitry in these related psychiatric disorders, and may have relevance for current and novel therapeutic approaches.

Emotional Processing in Obsessive-Compulsive Disorder: A Systematic Review and Meta-analysis of 25 Functional Neuroimaging Studies

BACKGROUND

Patients with obsessive-compulsive disorder (OCD) experience aversive emotions in response to obsessions, motivating avoidance and compulsive behaviors. However, there is considerable ambiguity regarding the brain circuitry involved in emotional processing in OCD, especially whether activation is altered in the amygdala.

METHODS

We conducted a systematic literature review and performed a meta-analysis-seed-based d mapping-of 25 whole-brain neuroimaging studies (including 571 patients and 564 healthy control subjects) using functional magnetic resonance imaging or positron emission tomography, comparing brain activation of patients with OCD and healthy control subjects during presentation of emotionally valenced versus neutral stimuli. Meta-regressions were employed to investigate possible moderators.

RESULTS

Patients with OCD, compared with healthy control subjects, showed increased activation in the bilateral amygdala, right putamen, orbitofrontal cortex extending into the anterior cingulate and ventromedial prefrontal cortex, and middle temporal and left inferior occipital cortices during emotional processing. Right amygdala hyperactivation was most pronounced in unmedicated patients. Symptom severity was related to increased activation in the orbitofrontal and anterior cingulate cortices and precuneus. Greater comorbidity with mood and anxiety disorders was associated with higher activation in the right amygdala, putamen, and insula as well as with lower activation in the left amygdala and right ventromedial prefrontal cortex.

CONCLUSIONS

Patients with OCD show increased emotional processing-related activation in limbic, frontal, and temporal regions. Previous mixed evidence regarding the role of the amygdala in OCD has likely been influenced by patient characteristics (such as medication status) and low statistical power.

Compensatory frontoparietal activity during working memory: an endophenotype of obsessive-compulsive disorder

BACKGROUND

Subtle deficits in executive functioning are present in patients with obsessive-compulsive disorder (OCD) and their first-degree relatives, suggesting involvement of the frontoparietal circuits. The neural correlates of working memory may be a neurocognitive endophenotype of OCD.

METHODS

Forty-three unmedicated OCD patients, 17 unaffected siblings, and 37 matched comparison subjects performed a visuospatial n-back task, with a baseline condition (N0) and three working memory load levels (N1, N2, N3) during functional magnetic resonance imaging. Task-related brain activity was compared between groups in frontoparietal regions of interest. Generalized psychophysiological interaction analyses were used to study task-related changes in functional connectivity.

RESULTS

Obsessive-compulsive disorder patients, compared with comparison subjects and siblings, showed increased error rates at N3. Compared with comparison subjects, OCD patients showed task-related hyperactivation in left dorsal frontal areas and left precuneus associated with better task performance. Siblings exhibited hyperactivation in a bilateral frontoparietal network. Increased task load was associated with increased task-related brain activity, but in OCD patients and siblings this increase was smaller from load N2 to N3 than in comparison subjects. Obsessive-compulsive disorder patients, compared with siblings and comparison subjects, showed increased task-related functional connectivity between frontal regions and bilateral amygdala.

CONCLUSIONS

These findings indicate that compensatory frontoparietal brain activity in OCD patients and their unaffected relatives preserves task performance at low task loads but is insufficient to maintain performance at high task loads. Frontoparietal dysfunction may constitute a neurocognitive endophenotype for OCD, possibly reflecting limbic interference with and neural inefficiency within the frontoparietal network.

Reduced fronto-callosal fiber integrity in unmedicated OCD patients: a diffusion tractography study

It is widely accepted that abnormalities in the frontal area of the brain underpin the pathophysiology of obsessive-compulsive disorder (OCD). Fundamental to this investigation is the delineation of frontal white matter tracts including dorsal and ventral frontal projections of interhemispheric connections. While previous investigations of OCD have examined the dorsal and ventral frontal regions, the corresponding callosal connections have not been investigated, despite their importance. We recruited twenty patients with OCD (15 drug-naïve and 5 currently unmedicated) and demographically similar healthy controls, and conducted fiber tractography and post hoc quantitative analysis using diffusion tensor imaging. We extracted fractional anisotropy (FA) of the fronto-callosal fibers along the entire length of the tract. Function-specific [by the Brodmann area region-of-interest (ROI) approach] and region-specific (by the length-parameterization approach) tracts were defined. In addition, we devised a new index of dorsal-ventral imbalance (DVII) of fiber integrity. Significant FA decreases were observed in orbitofrontal and dorsolateral prefrontal projections of the corpus callosum (P < 0.05, false discovery rate-corrected) with higher function/region sensitivity than voxel-based or ROI-based approaches. Importantly, OCD patients also exhibited significantly higher ventral-greater-than-dorsal asymmetry of FA values than normal controls (P < 0.05, FDR-corrected). This study is the first to investigate fiber integrity in the dorsal/ventral frontal parts of the callosal tractography in unmedicated OCD patients. Using a more quantitative method in terms of functional and regional specificity than previous studies, we report abnormalities in interhemispheric connectivity of both dorsal and ventral networks in the pathophysiology of OCD.

The involvement of distinct neural systems in patients with obsessive-compulsive disorder with autogenous and reactive obsessions

OBJECTIVE

To investigate the regional metabolite abnormalities and changes after treatment in patients with OCD with autogenous and reactive obsessions.

METHOD

We assessed right anterior cingulate cortex (ACC) and amygdala-hippocampal region (Am + Hpp) N-acetyl-aspartate (NAA), choline (Cho) and creatine (Cr) concentrations and NAA/Cr and Cho/Cr ratios using single-voxel proton magnetic resonance spectroscopy in 15 patients with autogenous obsessions (OCD-A), 15 patients with reactive obsessions (OCD-R) and 15 healthy controls (HC). Measurements were repeated after 16 weeks of fluoxetine treatment.

RESULTS

Baseline ACC NAA/Cr ratios of both OCD groups were significantly lower than HC. OCD-A group had significantly lower baseline NAA/Cr ratios in the Am + Hpp than other groups. These differences were more likely to be explained by higher Cr levels in ACC. We found no significant differences and changes for Cho levels and Cho/Cr ratios between groups and within groups. Significant increase in NAA/Cr ratios of OCD-A group found in the Am + Hpp was more likely to be explained by increased NAA levels. No significant changes were found in ACC NAA/Cr ratios.

CONCLUSION

While disturbed energy metabolism in ACC might reflect a common pathology in patients with OCD regardless of symptom dimension, alterations in mesiotemporal lobe are more likely for autogenous obsessions.

Dopamine D(1) receptor binding in the anterior cingulate cortex of patients with obsessive-compulsive disorder

Functional neuroimaging studies in patients with obsessive-compulsive disorder (OCD) suggest there is a hyperactivation of the anterior cingulate cortex (ACC) during provocation of symptoms and conflict-inhibition tasks. Since dopamine, acting through D(1) receptors is suggested to modulate ACC activity, we hypothesised that there would be an altered D(1) binding potential (BP) in the ACC of OCD patients. Using [(11)C]-SCH23390 and positron emission tomography, we report significantly reduced D(1) BP in seven drug-free OCD patients compared with matched healthy controls. These findings suggest mesocortical dopamine inputs via D(1) receptors may play a role in the aetiology of OCD.

Neuroimaging in obsessive-compulsive disorder

Many neuroimaging studies have investigated the pathophysiology of obsessive-compulsive disorder. These studies have contributed greatly to the development of contemporary neurocircuitry models of obsessive-compulsive disorder, which emphasize the dysfunction of fronto-striato-thalamocortical circuitry in obsessive-compulsive disorder patients. Specifically, dysfunctions of the orbitofrontal cortex, anterior cingulate cortex, thalamus and caudate nucleus have been revealed through resting state or symptom provocation studies. In addition, dysfunctional activations in the dorsolateral prefrontal cortex and parietal regions have been reported. Recently, these findings have led to the suggestion that the pathogenesis of obsessive-compulsive disorder involves an imbalance between dorsal and ventral fronto-striatal circuits. In this review, we provide updated findings on structural and functional neuroimaging studies performed with obsessive-compulsive disorder patients. The limitations of traditional imaging techniques and recent developments to overcome them will also be discussed.

Selective impairment in visual perception of biological motion in obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is associated with a variety of well-documented cognitive deficits such as deficits in memory and executive functioning, but little is known about basic perceptual concomitants of OCD. This study investigated global, configural processing in OCD using dynamic (moving) and static stimuli with minimal demands on cognitive function. Twenty OCD patients and 16 age- and education-matched healthy control subjects were tested on four perceptual tasks: two motion tasks involved detection and discrimination of human activity portrayed by point-light animations ("biological" motion). The other two tasks involved detection of coherent, translational motion defined by random-dot cinematograms and detection of static global shape defined by spatially distributed contours. OCD patients exhibited impaired performance on biological motion tasks; in contrast, their performance on tasks of coherent motion detection and global form perception were comparable to those of healthy controls. These results indicate that OCD patients have a specific deficit in perceiving biological motion signals, whereas their perception of non-biological coherent motion and static global shape is intact. Because efficient social interactions depend on accurate and rapid perception of subtle socially relevant cues, deficits in biological motion perception may compromise social functioning in people with OCD.

Cortical thinning in obsessive compulsive disorder

Although studies of obsessive-compulsive disorder (OCD) over the last 20 years have suggested abnormalities in frontal-subcortical circuitry, evidences of structural abnormalities in those areas are still imperfect and contradictory. With recent advances in neuroimaging technology, it is now possible to study cortical thickness based on cortical surfaces, which offers a direct quantitative index of cortical mass. Using the constrained Laplacian-based automated segmentation with proximities (CLASP) algorithm, we measured cortical thickness of 55 patients with OCD (33 men and 22 women) and 52 age- and sex-matched healthy volunteers (32 men and 20 women). We found multiple regions of cortical thinning in OCD patients compared to the normal control group. Patients with OCD had thinner left inferior frontal, left middle frontal, left precentral, left superior temporal, left parahippocampal, left orbitofrontal, and left lingual cortices. Most thinned regions were located in the left ventral cortex system, providing a new perspective that this ventral cortical system may be involved in the pathophysiology of OCD.

Neurocognitive indices of executive hypercontrol in obsessive-compulsive disorder

OBJECTIVE

Cognitive impairment, more often involving memory and/or executive functions, has been reported in obsessive-compulsive (OC) patients. The present study aimed at: i) replicating, in an independent sample, previous findings by our group showing neurocognitive slowness limited to executive tasks; ii) assessing the influence of deficit in general cognitive abilities on executive dysfunction.

METHOD

A comprehensive neuropsychological battery was administered to 30 drug-free OC patients and 30 healthy controls.

RESULTS

Obsessive-compulsive patients performed worse on visuospatial tests, were slower on executive tasks, and performed worse on the Wisconsin Card Sorting Test. After covarying for Wechsler Adult Intelligence Scale-Revised performance Intellectual Quotient, a lesser degree of executive dysfunction was observed.

CONCLUSION

Obsessive-compulsive patients exhibit an impairment of executive functions, especially when tasks also require visuospatial abilities. The impairment might reflect a hyperactivity of the executive control.

Neurobiologie bei Tic- und Zwangsstörungen

Zusammenfassung. Erst in den letzten Jahren wird auch in der Forschung vermehrtes Augenmerk auf die Überschneidung von Tic- und Zwangsstörungen gerichtet. Während in Übersichtsarbeiten zum gemeinsamen Auftreten von Tic- und Zwangsstörungen die zahlreichen Befunde zu Phänomenologie, begleitender Psychopathologie, Epidemiologie und daraus resultierenden Therapieimplikationen breiten Raum einnehmen, sind die Untersuchungsergebnisse hinsichtlich ätiologischer und pathophysiologischer Gemeinsamkeiten in entsprechenden Arbeiten unterrepräsentiert. Daher wird mit dieser Arbeit ein Überblick über den aktuellen neurobiologischen Forschungsstand zu den Gemeinsamkeiten und Unterschieden von Tic- und Zwangsstörungen gegeben.

Neuropsychological profiles of patients with obsessive-compulsive disorder: early onset versus late onset

In this study, we assess the neuropsychological profiles of both early and late symptom-onset obsessive-compulsive disorder (OCD) patients. The early and late-onset OCD patients are compared to the control group with a series of neuropsychological measurements. The late-onset OCD patients exhibited impaired performance on the immediate and the delayed recall conditions of the Rey-Osterrieth Complex Figure Test (RCFT) and the letter and category fluency of the Controlled Oral Word Association Test (COWA), compared to the normal controls and the early-onset OCD patients. The controls and early-onset OCD patients did not differ on any of the neuropsychological measurements taken in this study. These results suggest that different neurophysiological mechanisms are in play in early and late-onset OCD patients, and age of onset can serve as a potential marker for the subtyping of OCD.