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

Convergent functional change of frontoparietal network in obsessive-compulsive disorder: a voxel-based meta-analysis

Background

Obsessive-compulsive disorder (OCD) is a chronic psychiatric illness with complex clinical manifestations. Cognitive dysfunction may underlie OC symptoms. The frontoparietal network (FPN) is a key region involved in cognitive control. However, the findings of impaired FPN regions have been inconsistent. We employed meta-analysis to identify the fMRI-specific abnormalities of the FPN in OCD.

Methods

PubMed, Web of Science, Scopus, and EBSCOhost were searched to screen resting-state functional magnetic resonance imaging (rs-fMRI) studies exploring dysfunction in the FPN of OCD patients using three indicators: the amplitude of low-frequency fluctuation/fractional amplitude of low-frequency fluctuation (ALFF/fALFF), regional homogeneity (ReHo) and functional connectivity (FC). We compared all patients with OCD and control group in a primary analysis, and divided the studies by medication in secondary meta-analyses with the activation likelihood estimation (ALE) algorithm.

Results

A total of 31 eligible studies with 1359 OCD patients (756 men) and 1360 healthy controls (733 men) were included in the primary meta-analysis. We concluded specific changes in brain regions of FPN, mainly in the left dorsolateral prefrontal cortex (DLPFC, BA9), left inferior frontal gyrus (IFG, BA47), left superior temporal gyrus (STG, BA38), right posterior cingulate cortex (PCC, BA29), right inferior parietal lobule (IPL, BA40) and bilateral caudate. Additionally, altered connectivity within- and between-FPN were observed in the bilateral DLPFC, right cingulate gyrus and right thalamus. The secondary analyses showed improved convergence relative to the primary analysis.

Conclusion

OCD patients showed dysfunction FPN, including impaired local important nodal brain regions and hypoconnectivity within the FPN (mainly in the bilateral DLPFC), during the resting state. Moreover, FPN appears to interact with the salience network (SN) and default mode network (DMN) through pivotal brain regions. Consistent with the hypothesis of fronto-striatal circuit dysfunction, especially in the dorsal cognitive circuit, these findings provide strong evidence for integrating two pathophysiological models of OCD.

Heterogeneous Brain Abnormalities in Schizophrenia Converge on a Common Network Associated With Symptom Remission

BACKGROUND AND HYPOTHESIS

There is a huge heterogeneity of magnetic resonance imaging findings in schizophrenia studies. Here, we hypothesized that brain regions identified by structural and functional imaging studies of schizophrenia could be reconciled in a common network.

STUDY DESIGN

We systematically reviewed the case-control studies that estimated the brain morphology or resting-state local function for schizophrenia patients in the literature. Using the healthy human connectome (n = 652) and a validated technique "coordinate network mapping" to identify a common brain network affected in schizophrenia. Then, the specificity of this schizophrenia network was examined by independent data collected from 13 meta-analyses. The clinical relevance of this schizophrenia network was tested on independent data of medication, neuromodulation, and brain lesions.

STUDY RESULTS

We identified 83 morphological and 60 functional studies comprising 7389 patients with schizophrenia and 7408 control subjects. The "coordinate network mapping" showed that the atrophy and dysfunction coordinates were functionally connected to a common network although they were spatially distant from each other. Taking all 143 studies together, we identified the schizophrenia network with hub regions in the bilateral anterior cingulate cortex, insula, temporal lobe, and subcortical structures. Based on independent data from 13 meta-analyses, we showed that these hub regions were specifically connected with regions of cortical thickness changes in schizophrenia. More importantly, this schizophrenia network was remarkably aligned with regions involving psychotic symptom remission.

CONCLUSIONS

Neuroimaging abnormalities in cross-sectional schizophrenia studies converged into a common brain network that provided testable targets for developing precise therapies.

Systematic review and meta-analysis: multimodal functional and anatomical neural alterations in autism spectrum disorder

BACKGROUND

This meta-analysis aimed to explore the most robust findings across numerous existing resting-state functional imaging and voxel-based morphometry (VBM) studies on the functional and structural brain alterations in individuals with autism spectrum disorder (ASD).

METHODS

A whole-brain voxel-wise meta-analysis was conducted to compare the differences in the intrinsic functional activity and gray matter volume (GMV) between individuals with ASD and typically developing individuals (TDs) using Seed-based d Mapping software.

RESULTS

A total of 23 functional imaging studies (786 ASD, 710 TDs) and 52 VBM studies (1728 ASD, 1747 TDs) were included. Compared with TDs, individuals with ASD displayed resting-state functional decreases in the left insula (extending to left superior temporal gyrus [STG]), bilateral anterior cingulate cortex/medial prefrontal cortex (ACC/mPFC), left angular gyrus and right inferior temporal gyrus, as well as increases in the right supplementary motor area and precuneus. For VBM meta-analysis, individuals with ASD displayed decreased GMV in the ACC/mPFC and left cerebellum, and increased GMV in the left middle temporal gyrus (extending to the left insula and STG), bilateral olfactory cortex, and right precentral gyrus. Further, individuals with ASD displayed decreased resting-state functional activity and increased GMV in the left insula after overlapping the functional and structural differences.

CONCLUSIONS

The present multimodal meta-analysis demonstrated that ASD exhibited similar alterations in both function and structure of the insula and ACC/mPFC, and functional or structural alterations in the default mode network (DMN), primary motor and sensory regions. These findings contribute to further understanding of the pathophysiology of ASD.

Local structural and functional MRI markers of compulsive behaviors and obsessive-compulsive disorder diagnosis within striatum-based circuits

BACKGROUND

Obsessive-compulsive disorder (OCD) is a classic disorder on the compulsivity spectrum, with diverse comorbidities. In the current study, we sought to understand OCD from a dimensional perspective by identifying multimodal neuroimaging patterns correlated with multiple phenotypic characteristics within the striatum-based circuits known to be affected by OCD.

METHODS

Neuroimaging measurements of local functional and structural features and clinical information were collected from 110 subjects, including 51 patients with OCD and 59 healthy control subjects. Linked independent component analysis (LICA) and correlation analysis were applied to identify associations between local neuroimaging patterns across modalities (including gray matter volume, white matter integrity, and spontaneous functional activity) and clinical factors.

RESULTS

LICA identified eight multimodal neuroimaging patterns related to phenotypic variations, including three related to symptoms and diagnosis. One imaging pattern (IC9) that included both the amplitude of low-frequency fluctuation measure of spontaneous functional activity and white matter integrity measures correlated negatively with OCD diagnosis and diagnostic scales. Two imaging patterns (IC10 and IC27) correlated with compulsion symptoms: IC10 included primarily anatomical measures and IC27 included primarily functional measures. In addition, we identified imaging patterns associated with age, gender, and emotional expression across subjects.

CONCLUSIONS

We established that data fusion techniques can identify local multimodal neuroimaging patterns associated with OCD phenotypes. The results inform our understanding of the neurobiological underpinnings of compulsive behaviors and OCD diagnosis.

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.

Pathological Networking of Gray Matter Dendritic Density With Classic Brain Morphometries in OCD

Importance

The pathogenesis of obsessive-compulsive disorder (OCD) may involve altered dendritic morphology, but in vivo imaging of neurite morphology in OCD remains limited. Such changes must be interpreted functionally within the context of the multimodal neuroimaging approach to OCD.

Objective

To examine whether dendritic morphology is altered in patients with OCD compared with healthy controls (HCs) and whether such alterations are associated with other brain structural metrics in pathological networks.

Design, Setting, and Participants

This case-control study used cross-sectional data, including multimodal brain images and clinical symptom assessments, from 108 patients with OCD and 108 HCs from 2014 to 2017. Patients with OCD were recruited from Shanghai Mental Health Center, Shanghai, China, and HCs were recruited via advertisements. The OCD group comprised unmedicated adults with a Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition) (DSM-IV) diagnosis of OCD, while the HCs were adults without any DSM-IV diagnosis, matched for age, sex, and education level. Data were analyzed from September 2019 to April 2023.

Exposure

DSM-IV diagnosis of OCD.

Main Outcomes and Measures

Multimodal brain imaging was used to compare neurite microstructure and classic morphometries between patients with OCD and HCs. The whole brain was searched to identify regions exhibiting altered morphology in patients with OCD and explore the interplay between the brain metrics representing these alterations. Brain-symptom correlations were analyzed, and the performance of different brain metric configurations were evaluated in distinguishing patients with OCD from HCs.

Results

Among 108 HCs (median [IQR] age, 26 [23-31] years; 50 [46%] female) and 108 patients with OCD (median [IQR] age, 26 [24-31] years; 46 [43%] female), patients with OCD exhibited deficient neurite density in the right lateral occipitoparietal regions (peak t = 3.821; P ≤ .04). Classic morphometries also revealed widely-distributed alterations in the brain (peak t = 4.852; maximum P = .04), including the prefrontal, medial parietal, cingulate, and fusiform cortices. These brain metrics were interconnected into a pathological brain network associated with OCD symptoms (global strength: HCs, 0.253; patients with OCD, 0.941; P = .046; structural difference, 0.572; P < .001). Additionally, the neurite density index exhibited high discriminatory power in distinguishing patients with OCD from HCs (accuracy, ≤76.85%), and the entire pathological brain network also exhibited excellent discriminative classification properties (accuracy, ≤82.87%).

Conclusions and Relevance

The findings of this case-control study underscore the utility of in vivo imaging of gray matter dendritic density in future OCD research and the development of neuroimaging-based biomarkers. They also endorse the concept of connectopathy, providing a potential framework for interpreting the associations among various OCD symptom-related morphological anomalies.

Functional and structural MRI based obsessive-compulsive disorder diagnosis using machine learning methods

BACKGROUND

The success of neuroimaging in revealing neural correlates of obsessive-compulsive disorder (OCD) has raised hopes of using magnetic resonance imaging (MRI) indices to discriminate patients with OCD and the healthy. The aim of this study was to explore MRI based OCD diagnosis using machine learning methods.

METHODS

Fifty patients with OCD and fifty healthy subjects were allocated into training and testing set by eight to two. Functional MRI (fMRI) indices, including amplitude of low-frequency fluctuation (ALFF), fractional ALFF (fALFF), regional homogeneity (ReHo), degree of centrality (DC), and structural MRI (sMRI) indices, including volume of gray matter, cortical thickness and sulcal depth, were extracted in each brain region as features. The features were reduced using least absolute shrinkage and selection operator regression on training set. Diagnosis models based on single MRI index / combined MRI indices were established on training set using support vector machine (SVM), logistic regression and random forest, and validated on testing set.

RESULTS

SVM model based on combined fMRI indices, including ALFF, fALFF, ReHo and DC, achieved the optimal performance, with a cross-validation accuracy of 94%; on testing set, the area under the receiver operating characteristic curve was 0.90 and the validation accuracy was 85%. The selected features were located both within and outside the cortico-striato-thalamo-cortical (CSTC) circuit of OCD. Models based on single MRI index / combined fMRI and sMRI indices underperformed on the classification, with a largest validation accuracy of 75% from SVM model of ALFF on testing set.

CONCLUSION

SVM model of combined fMRI indices has the greatest potential to discriminate patients with OCD and the healthy, suggesting a complementary effect of fMRI indices on the classification; the features were located within and outside the CSTC circuit, indicating an importance of including various brain regions in the model.

Abnormal voxel-mirrored homotopic connectivity in first-episode, drug-naïve patients with obsessive-compulsive disorder

Prior studies suggest that obsessive-compulsive disorder (OCD) can cause both anatomical and functional variations in the brain, but to date, altered functional synchronization between two functional hemispheres remains unclear in OCD patients. Voxel-mirrored homotopic connectivity (VMHC) is defined as the temporal correlation of spontaneous low-frequency blood oxygenation level-dependent signal fluctuations across mirror regions of hemisphere revealing the homotopic connectivity between each voxel in one hemisphere and its mirrored counterpart in the contralateral hemisphere. To investigate the alterations of brain regional function and VMHC in patients with OCD, the current study enrolled 103 OCD patients and 118 healthy controls, undergoing resting-state functional magnetic resonance imaging. Compared to healthy controls (HCs), patients had decreased VMHC in bilateral cerebellum, lingual and fusiform gyrus; bilateral paracentral lobule, pre and postcentral gyrus; and bilateral superior and middle temporal gyrus, putamen and bilateral precuneus without global signal regression. And we found mostly similar results after regressing global signals; apart from the regions mentioned above, decreased in bilateral cuneus and calcarine was also showed. Furthermore, the mean VMHC values of the left cerebellum were negatively correlated with the obsession scores (ρ = -.204, π = .039). The decreased values in right fusiform and putamen were negatively correlated with duration of disease (ρ = -.205, π = .038; ρ = -.196, π = .047). We confirmed a significant VMHC reduction in OCD patients in broad areas. Our findings suggest that the patients tend to disconnect information exchange across hemispheres.

Different degrees of nodes behind obsessive-compulsive symptoms of schizophrenia

Obsessive-compulsive symptoms are frequently observed in various psychiatric disorders, including obsessive-compulsive disorder, schizophrenia, depression, and anxiety. However, the underlying anatomical basis of these symptoms remains unclear. In this study, we aimed to investigate the mechanism of schizophrenia with obsessive-compulsive symptoms by using diffusion tensor imaging (DTI)-based structural brain connectivity analysis to assess the network differences between patients with obsessive-compulsive disorder (OCD), patients with schizophrenia showing obsessive-compulsive symptoms (SCH), schizophrenia patients with obsessive-compulsive symptoms due to clozapine (LDP), and healthy controls (CN). We included 21 patients with OCD, 20 patients with SCH, 12 patients with LDP, and 25 CN. All subjects underwent MRI scanning, and structural brain connections were estimated using diffusion tensor imaging for further analysis of brain connectivity. The topology and efficiency of the network and the characteristics of various brain regions were investigated. We assessed baseline YALE-BROWN OBSESSIVE COMPULSIVE SCALE (Y-BOCS), Positive and Negative Syndrome Scale (PANSS), and 24-item Hamilton Depression Scale (HAMD-24) scores. Our results showed significant differences among the SCH, OCD, and CN groups (p < 0.05) in the MRI-measured degree of the following nodes: the superior orbitofrontal gyrus (25Frontal_Med_Orb_L), lingual gyrus (47Lingual_L), postcentral gyrus (58Postcentral_R), and inferior temporal gyrus (90Temporal_Inf_R). Additionally, we found significant differences in the degree of the brain regions 02Precentral_R, 47Lingual_L, 58Postcentral_R, and 90Temporal_Inf_R between the CN, OCD, SCH, and LDP groups (p < 0.05). These findings suggest that alterations in the degree of nodes might be the mechanism behind obsessive-compulsive symptoms in schizophrenia.

Neural predictors of cognitive-behavior therapy outcome in anxiety-related disorders: a meta-analysis of task-based fMRI studies

BACKGROUND

Cognitive-behavior therapy (CBT) is a well-established first-line intervention for anxiety-related disorders, including specific phobia, social anxiety disorder, panic disorder/agoraphobia, generalized anxiety disorder, obsessive-compulsive disorder, and posttraumatic stress disorder. Several neural predictors of CBT outcome for anxiety-related disorders have been proposed, but previous results are inconsistent.

METHODS

We conducted a systematic review and meta-analysis of task-based functional magnetic resonance imaging (fMRI) studies investigating whole-brain predictors of CBT outcome in anxiety-related disorders (17 studies, n = 442).

RESULTS

Across different tasks, we observed that brain response in a network of regions involved in salience and interoception processing, encompassing fronto-insular (the right inferior frontal gyrus-anterior insular cortex) and fronto-limbic (the dorsomedial prefrontal cortex-dorsal anterior cingulate cortex) cortices was strongly associated with a positive CBT outcome.

CONCLUSIONS

Our results suggest that there are robust neural predictors of CBT outcome in anxiety-related disorders that may eventually lead (probably in combination with other data) to develop personalized approaches for the treatment of these mental disorders.

Structural and functional deficits and couplings in severe and moderate OCD

Changes in gray matter volume and functional connections have been frequently observed in patients with obsessive compulsive disorder. However, different grouping may cause diverse volume alterations and could draw more adverse conclusions about the pathophysiology of obsessive compulsive disorder(OCD). Most of them preferred to divide subjects into patients and healthy controls, rather than a detailed subgroup. Moreover, multimodal neuroimaging studies about structural-functional defects and couplings are rather rare. Our aim was to explore gray matter volume(GMV) and functional networks abnormalities induced by structural deficits based on severity of Yale-Brown Obsessive Compulsive Scale(Y-BOCS) symptom including OCD patients with severe(S-OCD, n = 31) and moderate symptoms(M-OCD, n = 42) and healthy controls (HCs, n = 54); Voxel-based morphometry(VBM) method was used to detect GMV differences among three groups, then used as masks according to one-way analysis of variance(ANOVA) results for the subsequent resting-state functional connectivity(rs-FC) analysis. Besides, correlation and subgroup analysis were performed to detect the potential roles of structural deficits between every two groups. ANOVA analysis showed that both S-OCD and M-OCD had increased volume in anterior cingulate cortex(ACC), left precuneus(L-Pre) and paracentral lobule(PCL), postcentral gyrus, left inferior occipital gyrus(L-IOG) and right superior occipital gyrus(R-SOG) and bilateral cuneus, middle occipital gyrus(MOG), and calcarine. Additionally, increased connections between Pre and angular gyrus(AG) and inferior parietal lobule(IPL) have been found. Moreover, connections between the left cuneus and lingual gyrus, between IOG and left lingual gyrus, fusiform and between L-MOG and cerebellum were also included. Subgroup analysis showed that decreased GMV in left caudate was negatively correlated with compulsion and total score in patients with moderate symptom compared to HCs. Our findings indicated that altered GMV in occipital-related regions, Pre, ACC and PCL and the disrupted FC networks including MOG-cerebellum and Pre-AG and IPL. Moreover, subgroup GMV analysis furtherly revealed negative associations between GMV changes and Y-BOCS symptom, offering preparatory proof for the involvement of structural and functional deficits in cortical-subcortical circuitry. Thus, they could provide insights into the neurobiological basis.

Altered frontoparietal connectivity in patients with obsessive-compulsive disorder during an fMRI cognitive reappraisal task

Patients with obsessive-compulsive disorder (OCD) present increased brain activity in orbitofrontal and limbic regions when experiencing negative emotions, which could be related to deficits in emotion regulation abilities. 30 OCD patients and 29 healthy controls (HC) performed a cognitive reappraisal functional magnetic resonance imaging (fMRI) task and completed emotion regulation and OCD symptomatology questionnaires. Besides task activation, connectivity was also compared between groups through psychophysiological interaction analysis (PPI), using regions previously reported to be hyperactive in OCD as seeds. Finally, brain-behavior correlations were performed between activation/connectivity strength in group differential regions and the questionnaires' scores, as well as the emotional ratings reported during the task. Behaviorally, patients with OCD were less successful than controls at lowering the emotional impact of negative images. At the brain level, there were no significant between-group differences in brain activation. Contrarily, PPI analyses showed that HC had increased frontoparietal connectivity when experiencing negative emotions in comparison to OCD patients, while this pattern was reversed when regulating emotions (increased connectivity in patients). Finally, frontoparietal connectivity was correlated with measures of emotion regulation success and OCD symptomatology. Our findings point towards frontoparietal altered connectivity as a potential compensatory mechanism during emotion regulation in OCD patients.

Efficacy of Non-Invasive Brain Stimulation for Refractory Obsessive-Compulsive Disorder: A Meta-Analysis of Randomized Controlled Trials

Obsessive-compulsive disorder (OCD) is a neuropsychiatric disorder, with 30−40% of OCD patients being unresponsive to adequate trials of anti-OCD drugs and cognitive behavior therapy. The aim of this paper is to investigate the efficacy of non-invasive brain stimulation (NIBS) on treating refractory OCD. With PubMed, Embase, PsycInfo, and Cochrane Library used on 15 February 2022, 24 randomized controlled trials involving 663 patients were included. According to this analysis, NIBS including repetitive transcranial magnetic stimulation (rTMS), theta-burst stimulation (TBS), and transcranial direct current stimulation (tDCS), had a moderate effect on the reduction of Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores (SMD = 0.54, 95% CI: 0.26−0.81; p < 0.01). In the subgroup analysis, rTMS seemed to produce a better therapeutic effect (SMD = 0.73, 95% CI: 0.38−1.08; p < 0.01). Moreover, excitatory (SMD = 1.13, 95% CI: 0.24−2.01; p = 0.01) and inhibitory (SMD = 0.81, 95% CI: 0.26−1.36; p < 0.01) stimulation of the dorsolateral prefrontal cortex (DLPFC) both alleviated OCD symptoms. In the secondary outcome of clinical response rates, NIBS treatment led to an increase in response rates (RR = 2.26, 95% CI: 1.57−3.25; p < 0.01).

Gray Matter Volume Abnormality in Chronic Pain Patients With Depressive Symptoms: A Systemic Review and Meta-Analysis of Voxel-Based Morphometry Studies

Background

Gray matter volume (GMV) alteration in specific brain regions has been widely regarded as one of the most important neuroplasticity features in chronic pain patients with depressive symptoms (CP-D). However, the consistent and significant results were still lacking. Thus, further exploration was suggested to be performed.

Objectives

This study aimed to comprehensively collect the voxel-based morphometry (VBM) studies on GMV alteration between CP-D and healthy controls (HCs). And a systemic review and meta-analysis were made to explore the characteristic brain regions in chronic pain and depression comorbidity.

Methods

Search of PubMed, MEDLINE, Web of Science, and Cochrane Library databases updated to July 13, 2021. The altered GMV between CP-D and HCs in VBM studies was included in this meta-analysis. In total, 18 studies (20 datasets) and 1320 participants (520 patients and 800 HCs) were included. The significant coordinate information (x, y, z) reported in standard space and the effect size (t-value or z-score) were extracted and analyzed by anisotropic effect size-signed differential mapping (AES-SDM) 5.15 software.

Results

According to the main analysis results, CP-D showed significant and consistent increased GMV in the left hippocampus (HIP. L) and decreased GMV in the medial part of the left superior frontal gyrus (SFG. L, BA 10) compared to HCs. Subgroup analysis showed significant decreased GMV in the medial orbital part of SFG.R (BA 10) in neuropathic pain, as well as significant increased GMV in the right parahippocampal gyrus (PHG.R, BA 35), left hippocampus (HIP.L, BA 20), and right middle frontal gyrus (MFG.R) in musculoskeletal pain. Furthermore, meta-regression showed a positive relationship between the decreased GMV in the medial part of SFG.L and the percentage of female patients.

Conclusion

GMV abnormality in specific brain areas (e.g., HIP.L and SFG) was robust and reproducible, which could be significantly involved in this comorbidity disease. The findings in this study may be a valuable reference for future research.

Systematic Review Registration

[www.crd.york.ac.uk/prospero/].

Multimodal meta-analysis of structural gray matter, neurocognitive and social cognitive fMRI findings in schizophrenia patients

Neuroimaging research has shown that patients with schizophrenia (SCZ) present brain structural and functional alterations, but the results across imaging modalities and task paradigms are difficult to reconcile. Specifically, no meta-analyses have tested whether the same brain systems that are structurally different in SCZ patients are also involved in neurocognitive and social cognitive tasks. To answer this, we conducted separate meta-analyses of voxel-based morphometry, neurocognitive functional magnetic resonance imaging (fMRI), and social cognitive fMRI studies. Next, with a multimodal approach, we identified the common alterations across meta-analyses. Further exploratory meta-analyses were performed taking into account several clinical variables (illness duration, medication status, and symptom severity). A cluster covering the dorsomedial prefrontal cortex (dmPFC) and the supplementary motor area (SMA), and the right inferior frontal gyrus (IFG), presented shared structural and neurocognitive-related activation decreases, while the right angular gyrus presented shared decreases between structural and social cognitive-related activation. The exploratory meta-analyses replicated to some extent these findings, while new regions of alterations appeared in patient subgroups with specific clinical features. In conclusion, we found task-specific correlates of brain structure and function in SCZ, which help summarize and integrate a growing literature.

Longitudinal changes in neurometabolite concentrations in the dorsal anterior cingulate cortex after concentrated exposure therapy for obsessive-compulsive disorder

BACKGROUND

The dorsal anterior cingulate cortex (dACC) plays an important role in the pathophysiology of obsessive-compulsive disorder (OCD) due to its role in error processing, cognitive control and emotion regulation. OCD patients have shown altered concentrations in neurometabolites in the dACC, particularly Glx (glutamate+glutamine) and tNAA (N-acetylaspartate+N-acetyl-aspartyl-glutamate). We investigated the immediate and prolonged effects of exposure and response prevention (ERP) on these neurometabolites.

METHODS

Glx and tNAA concentrations were measured using magnetic resonance spectroscopy (1H-MRS) in 24 OCD patients and 23 healthy controls at baseline. Patients received concentrated ERP over four days. A subset was re-scanned after one week and three months.

RESULTS

No Glx and tNAA abnormalities were observed in OCD patients compared to healthy controls before treatment or over time. Patients with childhood or adult onset differed in the change over time in tNAA (F(2,40) = 7.24, ɳ²_p= 0.27, p = 0.004): concentrations increased between one week after treatment and follow-up in the childhood onset group (t(39) = -2.43, d = -0.86, p = 0.020), whereas tNAA concentrations decreased between baseline and follow-up in patients with an adult onset (t(42) = 2.78, d = 1.07, p = 0.008). In OCD patients with versus without comorbid mood disorders, lower Glx concentrations were detected at baseline (t(38) = -2.28, d = -1.00, p = 0.028). Glx increased after one week of treatment within OCD patients with comorbid mood disorders (t(30) = -3.09, d = -1.21, p = 0.004).

LIMITATIONS

Our OCD sample size allowed the detection of moderate to large effect sizes only.

CONCLUSION

ERP induced changes in neurometabolites in OCD seem to be dependent on mood disorder comorbidity and disease stage rather than OCD itself.

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.

Functional connectivity alterations between default mode network and occipital cortex in patients with obsessive-compulsive disorder (OCD)

Altered brain network connectivity is a potential biomarker for obsessive-compulsive disorder (OCD). A meta-analysis of resting-state MRI studies by Gürsel et al. (2018) described altered functional connectivity in OCD patients within and between the default mode network (DMN), the salience network (SN), and the frontoparietal network (FPN), as well as evidence for aberrant fronto-striatal circuitry. Here, we tested the replicability of these meta-analytic rsfMRI findings by measuring functional connectivity during resting-state fMRI in a new sample of OCD patients (n = 24) and matched controls (n = 33). We performed seed-to-voxel analyses using 30 seed regions from the prior meta-analysis. OCD patients showed reduced functional connectivity between the SN and the DMN compared to controls, replicating previous findings. We did not observe significant group differences of functional connectivity within the DMN, SN, nor FPN. Additionally, we observed reduced connectivity between the visual network to both the DMN and SN in OCD patients, in particular reduced functional connectivity between lateral parietal seeds and the left inferior lateral occipital pole. Furthermore, the right lateral parietal seed (associated with the DMN) was more strongly correlated with a cluster in the right lateral occipital cortex and precuneus (a region partly overlapping with the Dorsal Attentional Network (DAN)) in patients. Importantly, this latter finding was positively correlated to OCD symptom severity. Overall, our study partly replicated prior meta-analytic findings, highlighting hypoconnectivity between SN and DMN as a potential biomarker for OCD. Furthermore, we identified changes between the SN and the DMN with the visual network. This suggests that abnormal connectivity between cortex regions associated with abstract functions (transmodal regions such as the DMN), and cortex regions associated with constrained neural processing (unimodal regions such as the visual cortex), may be important in OCD.

The Role of Stress in Obsessive-Compulsive Disorder: A Narrative Review

Obsessive-compulsive disorder (OCD) has a worldwide prevalence of 2%-3%. Characterized by the presence of either one or two core symptoms-obsessions and compulsions-it generally runs a chronic course and may cause serious functional impairment. Though previously thought to be of psychogenic origin, the pathophysiology of OCD is now understood to be more complex. A multitude of environmental factors have been shown to contribute to the development of OCD, including infection, neonatal complications, childhood trauma, occurrence of stressful events, and brain injury. It has also been proposed that genetic vulnerability may play a role in OCD pathology, although candidate genes have yet to be identified. Likewise, although it is widely accepted that stress plays a role in OCD pathophysiology, the mechanisms remain unclear. Observations from the clinics indicate that stress may serve as both a triggering and aggravating factor, meaning it can prompt symptoms to appear while also contributing to their exacerbation. Additionally, dysfunction of the hypothalamic-pituitary-adrenal axis and impaired stress response have been identified in OCD patients. In this review, we analyze the role of stress in the pathophysiology of OCD, complemented by relevant findings from recent animal studies.

Temporal variability of regional intrinsic neural activity in drug-naïve patients with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) displays alterations in regional brain activity represented by the amplitude of low-frequency fluctuation (ALFF), but the time-varying characteristics of this local neural activity remain to be clarified. We aimed to investigate the dynamic changes of intrinsic brain activity in a relatively large sample of drug-naïve OCD patients using univariate and multivariate analyses. We applied a sliding-window approach to calculate the dynamic ALFF (dALFF) and compared the difference between 73 OCD patients and age- and sex-matched healthy controls (HCs). We also utilized multivariate pattern analysis to determine whether dALFF could differentiate OCD patients from HCs at the individual level. Compared with HCs, OCD patients exhibited increased dALFF mainly within regions of the cortical-striatal-thalamic-cortical (CSTC) circuit, including the bilateral dorsal anterior cingulate cortex, medial prefrontal cortex and striatum, and right dorsolateral prefrontal cortex (dlPFC). Decreased dALFF was identified in the bilateral inferior parietal lobule (IPL), posterior cingulate cortex, insula, fusiform gyrus, and cerebellum. Moreover, we found negative correlations between illness duration and dALFF values in the right IPL and between dALFF values in the left cerebellum and Hamilton Depression Scale scores. Furthermore, dALFF can distinguish OCD patients from HCs with the most discriminative regions located in the IPL, dlPFC, middle occipital gyrus, and cuneus. Taken together, in the current study, we demonstrated a characteristic pattern of higher variability of regional brain activity within the CSTC circuits and lower variability in regions outside the CSTC circuits in drug-naïve OCD patients.

Common neurofunctional dysregulations characterize obsessive-compulsive, substance use, and gaming disorders-An activation likelihood meta-analysis of functional imaging studies

Compulsivity and loss of behavioral control represent core symptoms in obsessive-compulsive disorder (OCD), substance use disorder (SUD), and internet gaming disorder (IGD). Despite elaborated animal models suggesting that compulsivity is mediated by cortico-striatal circuits and a growing number of neuroimaging case-control studies, common neurofunctional alterations in these disorders have not been systematically examined. The present activation likelihood estimation (ALE) meta-analysis capitalized on previous functional magnetic resonance imaging (fMRI) studies to determine shared neurofunctional alterations among the three disorders. Task-based fMRI studies of individuals with SUD, OCD, or IGD were obtained. ALE was performed within each disorder. Next, contrast and conjunction meta-analyses were performed to determine differential and common alterations. Task-paradigm classes were group according to Research Domain Criteria (RDoC) domains to determine contributions of underlying behavioral domains. One hundred forty-four articles were included representing data from n = 6897 individuals (SUD = 2418, controls = 2332; IGD = 361, controls = 360; OCD = 715, controls = 711) from case-control studies. Conjunction meta-analyses revealed shared alterations in the anterior insular cortex between OCD and SUDs. SUD exhibited additionally pronounced dorsal-striatal alterations compared with both, OCD and IGD. IGD shared frontal, particularly cingulate alterations with all SUDs, while IGD demonstrated pronounced temporal alterations compared with both, SUD and OCD. No robust overlap between IGD and OCD was observed. Across the disorders, neurofunctional alterations were mainly contributed by cognitive systems and positive valence RDoC domains. The present findings indicate that neurofunctional dysregulations in prefrontal regions engaged in regulatory-control represent shared neurofunctional alterations across substance and behavioral addictions, while shared neurofunctional dysregulations in the anterior insula may mediate compulsivity in substance addiction and OCD.

Set-shifting-related basal ganglia deformation as a novel familial marker of obsessive-compulsive disorder

The symptoms of obsessive-compulsive disorder (OCD) are suggestive of cognitive rigidity, and previous work identified impaired flexible responding on set-shifting tasks in such patients. The basal ganglia are central to habit learning and are thought to be abnormal in OCD, contributing to inflexible, rigid habitual patterns of behaviour. Here, we demonstrate that increased cognitive inflexibility, indexed by poor performance on the set-shifting task, correlated with putamen morphology, and that patients and their asymptomatic relatives had common curvature abnormalities within this same structure. The association between the structure of the putamen and the extradimensional errors was found to be significantly familial in OCD proband-relative pairs. The data implicate changes in basal ganglia structure linked to cognitive inflexibility as a familial marker of OCD. This may reflect a predisposing heightened propensity toward habitual response patterns and deficits in goal-directed planning.

Abnormalities of intrinsic brain activity in essential tremor: A meta-analysis of resting-state functional imaging

Neuroimaging studies using a variety of techniques have demonstrated abnormal patterns of spontaneous brain activity in patients with essential tremor (ET). However, the findings are variable and inconsistent, hindering understanding of underlying neuropathology. We conducted a meta‐analysis of whole‐brain resting‐state functional neuroimaging studies in ET compared to healthy controls (HC), using anisotropic effect‐size seed‐based d mapping, to identify the most consistent brain activity alterations and their relation to clinical features. After systematic literature search, we included 13 studies reporting 14 comparisons, describing 286 ET patients and 254 HC. Subgroup analyses were conducted considering medication status, head tremor status, and methodological factors. Brain activity in ET is altered not only in the cerebellum and cerebral motor cortex, but also in nonmotor cortical regions including prefrontal cortex and insula. Most of the results remained unchanged in subgroup analyses of patients with head tremor, medication‐naive patients, studies with statistical threshold correction, and the large subgroup of studies using functional magnetic resonance imaging. These findings not only show consistent and robust abnormalities in specific brain regions but also provide new information on the biology of patient heterogeneity, and thus help to elucidate the pathophysiology of ET.

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.

Focusing on Comorbidity-A Novel Meta-Analytic Approach and Protocol to Disentangle the Specific Neuroanatomy of Co-occurring Mental Disorders

BACKGROUND

In mental health, comorbidities are the norm rather than the exception. However, current meta-analytic methods for summarizing the neural correlates of mental disorders do not consider comorbidities, reducing them to a source of noise and bias rather than benefitting from their valuable information.

OBJECTIVES

We describe and validate a novel neuroimaging meta-analytic approach that focuses on comorbidities. In addition, we present the protocol for a meta-analysis of all major mental disorders and their comorbidities.

METHODS

The novel approach consists of a modification of Seed-based d Mapping-with Permutation of Subject Images (SDM-PSI) in which the linear models have no intercept. As in previous SDM meta-analyses, the dependent variable is the brain anatomical difference between patients and controls in a voxel. However, there is no primary disorder, and the independent variables are the percentages of patients with each disorder and each pair of potentially comorbid disorders. We use simulations to validate and provide an example of this novel approach, which correctly disentangled the abnormalities associated with each disorder and comorbidity. We then describe a protocol for conducting the new meta-analysis of all major mental disorders and their comorbidities. Specifically, we will include all voxel-based morphometry (VBM) studies of mental disorders for which a meta-analysis has already been published, including at least 10 studies. We will use the novel approach to analyze all included studies in two separate single linear models, one for children/adolescents and one for adults.

DISCUSSION

The novel approach is a valid method to focus on comorbidities. The meta-analysis will yield a comprehensive atlas of the neuroanatomy of all major mental disorders and their comorbidities, which we hope might help develop potential diagnostic and therapeutic tools.

Structural Imaging in OCD

Anatomical imaging in OCD using magnetic resonance imaging (MRI) has been performed since the late 1980s. MRI research was further stimulated with the advent of automated image processing techniques such as voxel-based morphometry (VBM) and surface-based methods (e.g., FreeSurfer) which allow for detailed whole-brain data analyses. Early studies suggesting involvement of corticostriatal circuitry (particularly orbitofrontal cortex and ventral striatum) have been complemented by meta-analyses and pooled analyses indicating additional involvement of posterior brain regions, in particular parietal cortex. Recent large-scale meta-analyses from the ENIGMA consortium have revealed greater pallidum and smaller hippocampus volume in adult OCD, coupled with parietal cortical thinning. Frontal cortical thinning was only observed in medicated patients. Previous reports of symptom dimension-specific alterations were not confirmed. In paediatric OCD, thalamus enlargement has been a consistent finding. Studies investigating white matter volume (VBM) or integrity (using diffusion tensor imaging (DTI)) have shown mixed results, with recent DTI meta-analyses mainly showing involvement of posterior cortical-subcortical tracts in addition to subcortical-prefrontal connections. To which extent these abnormalities are unique to OCD or common to other psychiatric disorders is unclear, as few comparative studies have been performed. Overall, neuroanatomical alterations in OCD appear to be subtle and may vary with time, stressing the need for adequately powered longitudinal studies. Although multivariate approaches using machine learning methodologies have so far been disappointing in distinguishing individual OCD patients from healthy controls, including multimodal data in such analyses may aid in further establishing a neurobiological profile of OCD.

Advances in multimodal data fusion in neuroimaging: Overview, challenges, and novel orientation

Multimodal fusion in neuroimaging combines data from multiple imaging modalities to overcome the fundamental limitations of individual modalities. Neuroimaging fusion can achieve higher temporal and spatial resolution, enhance contrast, correct imaging distortions, and bridge physiological and cognitive information. In this study, we analyzed over 450 references from PubMed, Google Scholar, IEEE, ScienceDirect, Web of Science, and various sources published from 1978 to 2020. We provide a review that encompasses (1) an overview of current challenges in multimodal fusion (2) the current medical applications of fusion for specific neurological diseases, (3) strengths and limitations of available imaging modalities, (4) fundamental fusion rules, (5) fusion quality assessment methods, and (6) the applications of fusion for atlas-based segmentation and quantification. Overall, multimodal fusion shows significant benefits in clinical diagnosis and neuroscience research. Widespread education and further research amongst engineers, researchers and clinicians will benefit the field of multimodal neuroimaging.

A Systematic Review of Behavioral, Physiological, and Neurobiological Cognitive Regulation Alterations in Obsessive-Compulsive Disorder

Obsessive-compulsive disorder (OCD) is characterized by cognitive regulation deficits. However, the current literature has focused on executive functioning and emotional response impairments in this disorder. Herein, we conducted a systematic review of studies assessing the behavioral, physiological, and neurobiological alterations in cognitive regulation in obsessive-compulsive patients using the PubMed database. Most of the studies included explored behavioral (distress, arousal, and frequency of intrusive thoughts) and neurobiological measures (brain activity and functional connectivity) using affective cognitive regulation paradigms. Our results pointed to the advantageous use of reappraisal and acceptance strategies in contrast to suppression to reduce distress and frequency of intrusive thoughts. Moreover, we observed alterations in frontoparietal network activity during cognitive regulation. Our conclusions are limited by the inclusion of underpowered studies with treated patients. Nonetheless, our findings support the OCD impairments in cognitive regulation of emotion and might help to improve current guidelines for cognitive therapy.

Stress Influences the Effect of Obsessive-Compulsive Symptoms on Emotion Regulation

Obsessive-compulsive disorder (OCD) is associated with emotion regulation impairments, namely the frequent use of maladaptive strategies such as suppression and the decreased use of reappraisal strategies. Additionally, these patients exhibit elevated stress levels. Since stress exposure affects emotion regulation abilities, stress might influence the relationship between obsessive-compulsive symptoms and emotion regulation. In this study, we explored the effects of stress and obsessive-compulsive symptoms on emotion regulation in a sample of healthy and OCD individuals. We used self-reported psychometric scales to measure stress levels, obsessive-compulsive symptoms, and emotion reappraisal and suppression skills. We applied multiple regression and mediation analyses. Our results demonstrated that increased reappraisal scores were associated with higher suppression scores. Additionally, elevated stress values predicted increased scores for suppression and decreased scores for reappraisal. Furthermore, the reappraisal abilities resulted from a combination of a direct effect of obsessive-compulsive symptoms and an indirect effect of obsessive-compulsive symptoms mediated by stress. The reliance on suppression strategies and the difficulty in using reappraisal approaches are explained by stress levels and are not directly explained by obsessive-compulsive symptoms. This study highlights the necessity of targeting stress in current therapy-based treatments for OCD.