Distinct grey matter volume alterations in adult patients with panic disorder and social anxiety disorder: A systematic review and voxel-based morphometry meta-analysis

Climate change on the brain: Neural correlates of climate anxiety

Climate change is a global crisis impacting individuals' mental health. Climate anxiety is an emerging area of interest within popular culture and the scientific community. Yet, little is known about the mechanisms underlying climate anxiety. We provide evidence that climate anxiety is related to gray matter volume in the midcingulate cortex as well as its level of functional connectivity with the insula cortex. These neuroanatomical and neurofunctional features of climate anxiety are involved in identifying and anticipating potential threats within the environment and preparing an appropriate action response to such threats. These neural correlates align with those observed in anxiety disorders. Yet, climate anxiety itself as well as the neural correlates of climate anxiety were related to pro-environmental behavior. This may suggest that the midcingulate and insula are part of a network linked to an adaptive aspect of climate anxiety in motivating behavioral engagement.

Grey matter structural alterations in anxiety disorders: a voxel-based meta-analysis

Anxiety disorders (ADs) are a group of prevalent and destructive mental illnesses, but the current understanding of their underlying neuropathology is still unclear. Employing voxel-based morphometry (VBM), previous studies have demonstrated several common brain regions showing grey matter volume (GMV) abnormalities. However, contradictory results have been reported among these studies. Considering that different subtypes of ADs exhibit common core symptoms despite different diagnostic criteria, and previous meta-analyses have found common core GMV-altered brain regions in ADs, the present research aimed to combine the results of individual studies to identify common GMV abnormalities in ADs. Therefore, we first performed a systematic search in PubMed, Embase, and Web of Science on studies investigating GMV differences between patients with ADs and healthy controls (HCs). Then, the anisotropic effect-size signed differential mapping (AES-SDM) was applied in this meta-analysis. A total of 24 studies (including 25 data sets) were included in the current study, and 906 patients with ADs and 1003 HCs were included. Compared with the HCs, the patients with ADs showed increased GMV in the left superior parietal gyrus, right angular gyrus, left precentral gyrus, and right lingual gyrus, and decreased GMV in the bilateral insula, bilateral thalamus, left caudate, and right putamen. In conclusion, the current study has identified some abnormal GMV brain regions that are related to the pathological mechanisms of anxiety disorders. These findings could contribute to a better understanding of the underlying neuropathology of ADs.

Smaller hypothalamic subregion with paraventricular nucleus in patients with panic disorder

In panic disorder (PD), functional disturbance of the hypothalamus-pituitary-adrenal (HPA) axis has been considered. However, in neuroimaging studies of PD, the hypothalamus and pituitary gland are poorly studied.We investigated the volume of PD patients' hypothalamus and pituitary gland, enrolling 38 PD patients and 38 healthy controls. Severity of PD was mild to moderate according to the Panic Disorder Severity Scale, and the illness duration was relatively short (median = 2.8 years). The hypothalamus' gray matter was automatically extracted and segmented, whereas the pituitary gland was manually traced. Regarding the hypothalamus, the paraventricular nucleus (PVH), which produces the corticotropin-releasing hormone, was of interest.The volumes of the pituitary and the bilateral anterior-superior hypothalamic subunits, where the PVH would be located, were compared by the multiple regression analyses controlling for age and intracranial content volume. To compensate for limitation in the abovementioned segmentation and analyses, the voxel-based morphometry with small volume correction (VBM-SVC) targeting the whole hypothalamus was also performed.The multiple regression analyses did not find significant effect of PD diagnosis on the volumes. However, in the VBM-SVC analysis, volume reduction of the PVH was suggested in PD even when patients who experienced PD for ≥ 3 years were excluded [peak coordinate (x, y, z = -2, 3, -8), FWE-corrected P = .022 (cluster-level) and 0.003 (peak-level), voxel size = 63]. Our results suggested structural alteration of the PVH in PD patients for the first time, indicating importance of the HPA-axis in PD pathology.

Age-dependent alterations in the coordinated development of subcortical regions in adolescents with social anxiety disorder

Subcortical brain regions play essential roles in the pathology of social anxiety disorder (SAD). While adolescence is the peak period of SAD, the relationships between altered development of the subcortical regions during this period and SAD are still unclear. This study investigated the age-dependent alterations in structural co-variance among subcortical regions and between subcortical and cortical regions, aiming to reflect aberrant coordination during development in the adolescent with SAD. High-resolution T1-weighted images were obtained from 76 adolescents with SAD and 67 healthy controls (HC), ranging from 11 to 17.9 years. Symptom severity was evaluated with the Social Anxiety Scale for Children (SASC) and the Depression Self Rating Scale for Children (DSRS-C). Structural co-variance and sliding age-window analyses were used to detect age-dependent group differences in inter-regional coordination patterns among subcortical regions and between subcortical and cortical regions. The volume of the striatum significantly correlated with SAD symptom severity. The SAD group exhibited significantly enhanced structural co-variance among key regions of the striatum (putamen and caudate). While the co-variance decreased with age in healthy adolescents, the co-variance in SAD adolescents stayed high, leading to more apparent group differences in middle adolescence. Moreover, the striatum's mean structural co-variance with cortical regions decreased with age in HC but increased with age in SAD. Adolescents with SAD suffer aberrant developmental coordination among the key regions of the striatum and between the striatum and cortical regions. The degree of incoordination is age-dependent, which may represent a neurodevelopmental trait of SAD.

Pre-COVID brain network topology prospectively predicts social anxiety alterations during the COVID-19 pandemic

Background

Social anxiety (SA) is a negative emotional response that can lead to mental health issues, which some have experienced during the coronavirus disease 2019 (COVID-19) pandemic. Little attention has been given to the neurobiological mechanisms underlying inter-individual differences in SA alterations related to COVID-19. This study aims to identify neurofunctional markers of COVID-specific SA development.

Methods

110 healthy participants underwent resting-state magnetic resonance imaging and behavioral tests before the pandemic (T1, October 2019 to January 2020) and completed follow-up behavioral measurements during the pandemic (T2, February to May 2020). We constructed individual functional networks and used graph theoretical analysis to estimate their global and nodal topological properties, then used Pearson correlation and partial least squares correlations examine their associations with COVID-specific SA alterations.

Results

In terms of global network parameters, SA alterations (T2-T1) were negatively related to pre-pandemic brain small-worldness and normalized clustering coefficient. In terms of nodal network parameters, SA alterations were positively linked to a pronounced degree centrality pattern, encompassing both the high-level cognitive networks (dorsal attention network, cingulo-opercular task control network, default mode network, memory retrieval network, fronto-parietal task control network, and subcortical network) and low-level perceptual networks (sensory/somatomotor network, auditory network, and visual network). These findings were robust after controlling for pre-pandemic general anxiety, other stressful life events, and family socioeconomic status, as well as by treating SA alterations as categorical variables.

Conclusions

The individual functional network associated with SA alterations showed a disrupted topological organization with a more random state, which may shed light on the neurobiological basis of COVID-related SA changes at the network level.

Altered Putamen Activation for Social Comparison-Related Feedback in Social Anxiety Disorder: A Pilot Study

INTRODUCTION

Social anxiety disorder (SAD) is characterized by abnormal processing of performance-related social stimuli. Previous studies have shown altered emotional experiences and activations of different sub-regions of the striatum during processing of social stimuli in patients with SAD. However, whether and to what extent social comparisons affect behavioural and neural responses to feedback stimuli in patients with SAD is unknown.

MATERIALS AND METHODS

To address this issue, emotional ratings and functional magnetic resonance imaging (fMRI) responses were assessed while patients suffering from SAD and healthy controls (HC) were required to perform a choice task and received performance feedback (correct, incorrect, non-informative) that varied in relation to the performance of fictitious other participants (a few, half, or most of others had the same outcome).

RESULTS

Across all performance feedback conditions, fMRI analyses revealed reduced activations in bilateral putamen when feedback was assumed to be received by only a few compared to half of the other participants in patients with SAD. Nevertheless, analysis of rating data showed a similar modulation of valence and arousal ratings in patients with SAD and HC depending on social comparison-related feedback.

CONCLUSIONS

This suggests altered neural processing of performance feedback depending on social comparisons in patients with SAD.

Abnormal causal connectivity of prefrontal-limbic circuit by structural deficits in drug-naive anxiety disorders

BACKGROUND

Structural and functional deficits in the prefrontal-limbic circuit have been revealed in patients with anxiety disorders. However, the effect of structural abnormalities on causal connectivity within this circuit remains unclear. This study aimed to investigate causal connectivity in the prefrontal-limbic circuit associated with structural deficits in drug-naive patients with generalized anxiety disorder (GAD) and panic disorder (PD) and the changes after treatment.

METHODS

A total of 64 GAD patients, 54 PD patients and 61 healthy controls (HCs) completed the resting-state magnetic resonance imaging scans at baseline. Among them, 96 patients with anxiety disorders (52 in GAD group and 44 in PD group) completed a 4-week paroxetine treatment. Voxel-based morphometry and Granger causality analysis (GCA) were applied to analyze the data based on the human brainnetome atlas.

RESULTS

Patients with GAD and PD showed decreased gray matter volume (GMV) in the bilateral A24cd subregions of cingulate gyrus. Whole-brain analysis revealed decreased GMV in the left cingulate gyrus in patients with PD. Hence, the left A24cd subregion was selected as a seed. Compared with HCs, unidirectional causal connectivity between the limbic-superior temporal gyrus (STG) temporal pole and the limbic-precentral/middle frontal gyrus was enhanced in patients with GAD and PD (from the left A24cd subregion of cingulate gyrus to the right STG temporal pole, and from the left A24cd subregion of cingulate gyrus to the right precentral/middle frontal gyrus). Compared with patients with PD, the limbic-precuneus unidirectional causal connectivity was enhanced in patients with GAD, and the cerebellum crus1 - limbic connectivity has a positive feedback effect.

CONCLUSIONS

The anatomical defects in the left A24cd subregion of cingulate gyrus may partially affect the prefrontal-limbic circuit, and the unidirectional causal effect from the left A24cd subregion to the right STG temporal pole may be an imaging change shared by anxiety disorders. The causal effect of the left A24cd subregion of cingulate gyrus to precuneus might be related to the neurobiology of GAD.

Gender differences in anxiety and depressive symptomatology determined by network analysis in panic disorder

BACKGROUND

It has been suggested that gender differences in anxiety and depressive symptoms characterize panic disorder (PD) in terms of vulnerability to stressful life events, anxiety, depressive symptom patterns, and brain structure. However, few studies have investigated the gender differences in PD using a network approach.

METHODS

This study included 619 participants with PD (313 men). The Panic Disorder Severity Scale, Albany Panic and Phobia Questionnaire, and Beck Depression Inventory-II were used to evaluate symptomatology. To investigate the PD-related white matter (WM) neural correlates, tract-based spatial statistics were used. The PD-related clinical scales and WM neural correlates were included in the network analysis to identify associations between variables. To evaluate network differences between genders, network comparison tests were conducted.

RESULTS

Our findings revealed that agoraphobia in men was the strongest central symptom. In addition, loss of pleasure, and not anxiety or panic symptoms, was the strongest central symptom in women with PD. The network comparison test revealed that the bridge strength score was higher in agoraphobia and tiredness in men and in self-criticalness in women. Furthermore, in the network that includes neural correlates of WM, the bridge strength score was higher in the cingulate gyrus WM in men and the cingulum hippocampus in women.

LIMITATIONS

Since this is a cross-sectional network study of PD patients, the causal relationship between interactions in this network analysis for both genders may not be accurately determined.

CONCLUSION

Network structures of anxiety and depressive symptomatology and related WM neural correlates can differ according to gender in PD patients.

Internet addiction-induced brain structure and function alterations: a systematic review and meta-analysis of voxel-based morphometry and resting-state functional connectivity studies

Internet addiction (IA) is a growing social concern and has been intensively studied in recent years. Previous imaging studies have shown that IA may impair brain structure and function, but with no robust conclusions. We conducted a systematic review and meta-analysis of neuroimaging studies in IA. Two separate meta-analyses were conducted for voxel-based morphometry (VBM) studies and resting-state functional connectivity (rsFC) studies. All meta-analyses were performed using two analysis methods activation likelihood estimation (ALE) and seed-based d mapping with permutation of subject images (SDM-PSI). The ALE analysis of VBM studies revealed less gray matter volume (GMV) in the supplementary motor area (SMA) (1176 mm³), anterior cingulate cortex (ACC) (one cluster size is 744 mm³ and the other is 688 mm³), and orbitofrontal cortex (OFC) (624 mm³) in subjects with IA. The SDM-PSI analysis showed less GMV in the ACC (56 voxels). The ALE analysis of rsFC studies showed stronger rsFC from posterior cingulate cortex (PCC) (880 mm³) or insula (712 mm³) to the whole brain in subjects with IA; however, the SDM-PSI analysis revealed no obvious rsFC alteration. These changes may underlie the core symptoms of IA, which include emotional regulation disorder, distraction, and impaired executive control. Our results reflect the common features of neuroimaging studies related to IA in recent years and may potentially help inform the development of more effective diagnostic and treatment approaches.

Volume of subcortical brain regions in social anxiety disorder: mega-analytic results from 37 samples in the ENIGMA-Anxiety Working Group

There is limited convergence in neuroimaging investigations into volumes of subcortical brain regions in social anxiety disorder (SAD). The inconsistent findings may arise from variations in methodological approaches across studies, including sample selection based on age and clinical characteristics. The ENIGMA-Anxiety Working Group initiated a global mega-analysis to determine whether differences in subcortical volumes can be detected in adults and adolescents with SAD relative to healthy controls. Volumetric data from 37 international samples with 1115 SAD patients and 2775 controls were obtained from ENIGMA-standardized protocols for image segmentation and quality assurance. Linear mixed-effects analyses were adjusted for comparisons across seven subcortical regions in each hemisphere using family-wise error (FWE)-correction. Mixed-effects d effect sizes were calculated. In the full sample, SAD patients showed smaller bilateral putamen volume than controls (left: d = -0.077, pFWE = 0.037; right: d = -0.104, pFWE = 0.001), and a significant interaction between SAD and age was found for the left putamen (r = -0.034, pFWE = 0.045). Smaller bilateral putamen volumes (left: d = -0.141, pFWE < 0.001; right: d = -0.158, pFWE < 0.001) and larger bilateral pallidum volumes (left: d = 0.129, pFWE = 0.006; right: d = 0.099, pFWE = 0.046) were detected in adult SAD patients relative to controls, but no volumetric differences were apparent in adolescent SAD patients relative to controls. Comorbid anxiety disorders and age of SAD onset were additional determinants of SAD-related volumetric differences in subcortical regions. To conclude, subtle volumetric alterations in subcortical regions in SAD were detected. Heterogeneity in age and clinical characteristics may partly explain inconsistencies in previous findings. The association between alterations in subcortical volumes and SAD illness progression deserves further investigation, especially from adolescence into adulthood.

Structural and Functional Neural Alterations in Internet Addiction: A Study Protocol for Systematic Review and Meta-Analysis

A growing number of neuroimaging studies have revealed abnormal brain structural and functional alterations in subjects with internet addiction (IA), however, with conflicting conclusions. We plan to conduct a systematic review and meta-analysis on the studies of voxelbased morphometry (VBM) and resting-state functional connectivity (rsFC), to reach a consolidated conclusion and point out the future direction in this field. A comprehensive search of rsFC and VBM studies of IA will be conducted in the PubMed, Cochrane Library, and Web of Science databases to retrieve studies published from the inception dates to August 2021. If the extracted data are feasible, activation likelihood estimation and seed-based d mapping methods will be used to meta-analyze the brain structural and functional changes in IA patients. This study will hopefully reach a consolidated conclusion on the impact of IA on human brain or point out the future direction in this field.

A Voxel-Based Morphometric Study of Gray Matter in Specific Phobia

The objective of this study was to analyze the neurostructural abnormalities of brain areas responsible for the acquisition and maintenance of fear in small animal phobia by comparing gray matter volume (GMV) in individuals with phobia and non-fearful controls. Structural magnetic resonance imaging was obtained from 62 adults (79% female) assigned to one of two groups: 31 were diagnosed with small animal phobia and 31 were non-fearful controls. To investigate structural alterations, a whole-brain voxel-based morphometry analysis was conducted to compare the GMV of the brain areas involved in fear between both groups. The results indicated that individuals with a small animal specific phobia showed smaller GMV in cortical regions, such as the orbitofrontal (OFC) and medial frontal cortex, and greater GMV in the putamen than non-fearful controls. These brain areas are responsible for avoidant behavior (putamen) and emotional regulation processes or inhibitory control (prefrontal cortex (PFC)), which might suggest a greater vulnerability of phobic individuals to acquiring non-adaptive conditioned responses and emotional dysregulation. The findings provide preliminary support for the involvement of structural deficits in OFC and medial frontal cortex in phobia, contributing to clarify the neurobiological substrates for phobias.

Associations between levels of Internet Gaming Disorder symptoms and striatal morphology-replication and associations with social anxiety

Background

Brain structural alterations of the striatum have been frequently observed in internet gaming disorder (IGD); however, the replicability of the results and the associations with social-affective dysregulations such as social anxiety remain to be determined.

Methods

The present study combined a dimensional neuroimaging approach with both voxel-wise and data-driven multivariate approaches to (i) replicate our previous results on a negative association between IGD symptom load (assessed by the Internet Gaming Disorder Scale-Short Form) and striatal volume, (ii) extend these findings to female individuals, and (iii) employ multivariate and mediation models to determine common brain structural representations of IGD and social anxiety (assessed by the Liebowitz Social Anxiety Scale).

Results

In line with the original study, the voxel-wise analyses revealed a negative association between IGD and volumes of the bilateral caudate. Going beyond the earlier study investigating only male participants, the present study demonstrates that the association in the right caudate was comparable in both the male and the female subsamples. Further examination using the multivariate approach revealed regionally different associations between IGD and social anxiety with striatal density representations in the dorsal striatum (caudate) and ventral striatum (nucleus accumbens). Higher levels of IGD were associated with higher social anxiety and the association was critically mediated by the multivariate neurostructural density variations of the striatum.

Conclusions

Altered striatal volumes may represent a replicable and generalizable marker of IGD symptoms. However, exploratory multivariate analyses revealed more complex and regional specific associations between striatal density and IGD as well as social anxiety symptoms. Variations in both tendencies may share common structural brain representations, which mediate the association between increased IGD and social anxiety.

Pathological fear, anxiety and negative affect exhibit distinct neurostructural signatures: evidence from psychiatric neuroimaging meta-analysis

Internalizing disorders encompass anxiety, fear and depressive disorders, which exhibit overlap at both conceptual and symptom levels. Given that a neurobiological evaluation is lacking, we conducted a Seed-based D-Mapping comparative meta-analysis including coordinates as well as original statistical maps to determine common and disorder-specific gray matter volume alterations in generalized anxiety disorder (GAD), fear-related anxiety disorders (FAD, i.e., social anxiety disorder, specific phobias, panic disorder) and major depressive disorder (MDD). Results showed that GAD exhibited disorder-specific altered volumes relative to FAD including decreased volumes in left insula and lateral/medial prefrontal cortex as well as increased right putamen volume. Both GAD and MDD showed decreased prefrontal volumes compared to controls and FAD. While FAD showed less robust alterations in lingual gyrus compared to controls, this group presented intact frontal integrity. No shared structural abnormalities were found. Our study is the first to provide meta-analytic evidence for distinct neuroanatomical abnormalities underlying the pathophysiology of anxiety-, fear-related and depressive disorders. These findings may have implications for determining promising target regions for disorder-specific neuromodulation interventions (e.g. transcranial magnetic stimulation or neurofeedback).

White matter hyperintensities-related cortical changes and correlation with mild behavioral impairment

PURPOSE

The aim of this study was to analyze cortical thickness and gray matter volume (GMV) changes in white matter hyperintensities (WMH) which were associated brain regions and their association with mild behavioral impairment (MBI) by means of voxel- and surface-based morphology (VBM and SBM).

METHODS

A total of 60 patients underwent 3T MRI scan and MBI checklist (MBI-C) assessment and were divided into two groups: lower WMH (LWMH) and higher WMH (HWMH). After adjusting for confounding factors i.e. age, gender, education, and total intracranial volume, we found a GMV decrease in the left anterior insula (AIns), right middle frontal gyrus, right central operculum, right fusiform gyrus, left cerebellum exterior, and thalamus proper in the HWMH group based VBM, while in the HWMH group based SBM we found cortical thickness decrease in the left lingual, right posterior cingulate cortex (rPCC), right precentral, left superior frontal, right medial orbitofrontal gyrus, and left pars opercularis.

RESULTS

The HWMH group had higher MBI-C scores. The GMV in the left AIns and thalamus proper and the thickness of rPCC negatively correlated with the MBI-C scores. The mediation analysis suggested that WMH may partially mediate MBI-C scores by reducing the GMV and cortical thickness of the mentioned brain regions.

CONCLUSIONS

In WMH patients, the occurrence of MBI is associated with atrophy of gray matter and cortex. The occurrence of MBI may be partially mediated by WMH through gray matter and cortical atrophy. It provides a new insight into the relationship between WMH and dementia.

An interpretable radiomics model for the diagnosis of panic disorder with or without agoraphobia using magnetic resonance imaging

BACKGROUND

Early and accurate diagnosis of panic disorder with or without agoraphobia (PDA) is crucial to reducing disease burden and individual suffering. However, its diagnosis is challenging for lack of validated biomarkers. This study aimed to investigate whether radiomic features extracted from T1-weighted images (T1) of major fear-circuit structures (amygdala, insula, and anterior cingulate cortex [ACC]) could differentiate patients with PDA from healthy controls (HCs).

METHODS

The 213 participants (93 PDA, 120 HCs) were allocated to training (n = 149) and test (n = 64) sets after undergoing magnetic resonance imaging. Radiomic features (n = 1498) were extracted from T1 of the studied structures. Machine learning models were trained after feature selection and then validated in the test set. SHapley Additive exPlanations (SHAP) explored the model interpretability.

RESULTS

We identified 29 radiomic features to differentiate participants with PDA from HCs. The area under the curve, accuracy, sensitivity, and specificity of the best performing radiomics model in the test set were 0.84 (95% confidence interval: 0.74-0.95), 81.3%, 75.0%, and 86.1%, respectively. The SHAP model explanation suggested that the energy features extracted from the bilateral long insula gyrus and central sulcus of the insula and right ACC were highly associated with the risk of PDA.

LIMITATIONS

This was a cross-sectional study with a relatively small sample size, and the causality of changes in radiomic features and their biological and clinical meanings remained to be elucidated.

CONCLUSIONS

Our findings suggest that radiomic features from the fear-circuit structures could unveil hidden microstructural aberrations underlying the pathogenesis of PDA that could help identify PDA.

SARS-CoV-2 is associated with changes in brain structure in UK Biobank

There is strong evidence for brain-related abnormalities in COVID-19 1-13 . It remains unknown however whether the impact of SARS-CoV-2 infection can be detected in milder cases, and whether this can reveal possible mechanisms contributing to brain pathology. Here, we investigated brain changes in 785 UK Biobank participants (aged 51-81) imaged twice, including 401 cases who tested positive for infection with SARS-CoV-2 between their two scans, with 141 days on average separating their diagnosis and second scan, and 384 controls. The availability of pre-infection imaging data reduces the likelihood of pre-existing risk factors being misinterpreted as disease effects. We identified significant longitudinal effects when comparing the two groups, including: (i) greater reduction in grey matter thickness and tissue-contrast in the orbitofrontal cortex and parahippocampal gyrus, (ii) greater changes in markers of tissue damage in regions functionally-connected to the primary olfactory cortex, and (iii) greater reduction in global brain size. The infected participants also showed on average larger cognitive decline between the two timepoints. Importantly, these imaging and cognitive longitudinal effects were still seen after excluding the 15 cases who had been hospitalised. These mainly limbic brain imaging results may be the in vivo hallmarks of a degenerative spread of the disease via olfactory pathways, of neuroinflammatory events, or of the loss of sensory input due to anosmia. Whether this deleterious impact can be partially reversed, or whether these effects will persist in the long term, remains to be investigated with additional follow up.

Sex is a defining feature of neuroimaging phenotypes in major brain disorders

Sex is a biological variable that contributes to individual variability in brain structure and behavior. Neuroimaging studies of population-based samples have identified normative differences in brain structure between males and females, many of which are exacerbated in psychiatric and neurological conditions. Still, sex differences in MRI outcomes are understudied, particularly in clinical samples with known sex differences in disease risk, prevalence, and expression of clinical symptoms. Here we review the existing literature on sex differences in adult brain structure in normative samples and in 14 distinct psychiatric and neurological disorders. We discuss commonalities and sources of variance in study designs, analysis procedures, disease subtype effects, and the impact of these factors on MRI interpretation. Lastly, we identify key problems in the neuroimaging literature on sex differences and offer potential recommendations to address current barriers and optimize rigor and reproducibility. In particular, we emphasize the importance of large-scale neuroimaging initiatives such as the Enhancing NeuroImaging Genetics through Meta-Analyses consortium, the UK Biobank, Human Connectome Project, and others to provide unprecedented power to evaluate sex-specific phenotypes in major brain diseases.

Adolescent anxiety disorders and the developing brain: comparing neuroimaging findings in adolescents and adults

Adolescence is the peak period for the incidence of anxiety disorders. Recent findings have revealed the immaturity of neural networks underlying emotional regulation in this population. Brain vulnerability to anxiety in adolescence is related to the unsynchronised development of anxiety-relevant brain functional systems. However, our current knowledge on brain deficits in adolescent anxiety is mainly borrowed from studies on adults. Understanding adolescent-specific brain deficits is essential for developing biomarkers and brain-based therapies targeting adolescent anxiety. This article reviews and compares recent neuroimaging literature on anxiety-related brain structural and functional deficits between adolescent and adult populations, and proposes a model highlighting the differences between adolescence and adulthood in anxiety-related brain networks. This model emphasises that in adolescence the emotional control system tends to be hypoactivated, the fear conditioning system is immature, and the reward and stress response systems are hypersensitive. Furthermore, the striatum’s functional links to the amygdala and the prefrontal cortex are strengthened, while the link between the prefrontal cortex and the amygdala is weakened in adolescence. This model helps to explain why adolescents are vulnerable to anxiety disorders and provides insights into potential brain-based approaches to intervene in adolescent anxiety disorders.

MRI tracking/detection of bone marrow mesenchymal stromal cells transplantation for treatment of ischemic cerebral infarction

Background

Cerebral stroke is the second leading cause of death with high mortality and morbidity worldwide, currently it lacks effective therapies to improve the prognosis. This study was aimed to explore the role of bone marrow mesenchymal stem cells (BMSCs) transplantation in the recovery of brain structure and function after ischemic cerebral infarction by magnetic resonance imaging (MRI).

Methods

By applying internal carotid artery embolization, the ischemic cerebral infarction model in rats was established. MRI was performed to detect the imaging changes in the brain tissue after modeling, and the successful modeling was evidenced by the presence of obvious high-signal infarct areas in the brain. BMSCs were then injected into the lateral ventricles of rats, and the recovery of brain tissue and function were quantitatively evaluated by T2-weighted image (T2WI) and voxel-based morphology (VBM) after 28 days.

Results

The results showed that BMSCs were cell subsets with multiple differentiation potentials. Deficits caused by Ischemic cerebral infarction were relieved by BMSCs transplantation, including increase in damaged cerebral tissue and recovery of cerebral function. In addition, the combined imaging technology of VBM and T2WI quantitatively revealed the effectiveness of BMSCs in repairing damaged brain tissue structure and function.

Conclusion

Taken together, the results revealed that the transplantation of BMSCs into the lateral ventricle was beneficial to repair the structure and function of the damaged brain tissue after ischemic cerebral infarction. Moreover, the combination of VBM and T2WI technology can detect the level of brain injury in ischemic cerebral infarction dynamically and noninvasively, and evaluate the recovery of structure and function of damaged brain tissue.

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.