Whole-brain volume alteration and its correlation with anxiety severity in patients with obsessive-compulsive disorder and generalized anxiety disorder

Grey matter alterations in generalized anxiety disorder: A voxel-wise meta-analysis of voxel-based morphometry studies

OBJECTIVE

Grey matter, a crucial component of the brain, has been found altered in generalized anxiety disorder (GAD) of several voxel-based morphometry studies. The conclusive and consistent grey matter alterations in GAD have not been confirmed.

METHOD

Eleven voxel-based morphometry studies of GAD patients were included in the current systematic review and meta-analysis. The linear model of anxiety severity scores was applied to explore the relationship of grey matter alterations and anxiety severity. The subgroup analysis of adult GAD and adolescent GAD was also performed.

RESULTS

Significantly modest grey matter alterations in the left superior temporal gyrus of patients with GAD were found. The anxiety severity score was significantly correlated with grey matter alterations in the right insula, lenticular nucleus, putamen and striatum. The subgroup analysis of adult GAD and adolescent GAD all failed to show significant grey matter alterations. However, in the adult GAD subgroup, anxiety severity score was significantly correlated with grey matter alterations in the right insula.

CONCLUSION

GAD might have the modest grey matter alterations in the left superior temporal gyrus. Anxiety severity might be related to the grey matter alterations in the limbic regions, such as the right insula, lenticular nucleus, putamen and striatum. This kind of correlation might be related to the effects of adult GAD. Future studies with adequate sample sizes and sophisticated GAD categories will be needed.

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.

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).

Medial prefrontal area reductions, altered expressions of cholecystokinin, parvalbumin, and activating transcription factor 4 in the corticolimbic system, and altered emotional behavior in a progressive rat model of type 2 diabetes

Metabolic disorders are associated with a higher risk of psychiatric disorders. We previously reported that 20-week-old Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of progressive type 2 diabetes, showed increased anxiety-like behavior and regional area reductions and increased cholecystokinin-positive neurons in the corticolimbic system. However, in which stages of diabetes these alterations in OLETF rats occur remains unclear. We aimed to investigate anxiety-like behavior and its possible mechanisms at different stages of type 2 diabetes in OLETF rats. Eight- and 30-week-old OLETF rats were used as diabetic animal models at the prediabetic and progressive stages of type 2 diabetes respectively, and age-matched Long-Evans Tokushima Otsuka rats served as non-diabetic controls. In the open-field test, OLETF rats showed less locomotion in the center zone and longer latency to leave the center zone at 8 and 30 weeks old, respectively. The areas of the medial prefrontal cortex were smaller in the OLETF rats, regardless of age. The densities of cholecystokinin-positive neurons in OLETF rats were higher in the lateral and basolateral amygdala only at 8 weeks old and in the anterior cingulate and infralimbic cortices and hippocampal cornu ammonis area 3 at both ages. The densities of parvalbumin-positive neurons of OLETF rats were lower in the cornu ammonis area 2 at 8 weeks old and in the prelimbic and infralimbic cortices at both ages. No apoptotic cell death was detected in OLETF rats, but the percentage of neurons co-expressing activating transcription factor 4 and cholecystokinin and parvalbumin was higher in OLETF rats at both ages in the anterior cingulate cortex and basolateral amygdala, respectively. These results suggest that altered emotional behavior and related neurological changes in the corticolimbic system are already present in the prediabetic stage of OLETF rats.

Subclinical depression and anxiety impact verbal memory functioning differently in men and women -an fMRI study

BACKGROUND

Depressive symptoms are known to affect memory efficiency in various populations. More specifically, several studies conducted in patients suffering from schizophrenia have indicated that memory efficiency is affected by depressed mood in female patients and by anxiety in male patients. We investigated, using neuroimaging techniques, whether similar gender-specific associations with subclinical depression and anxiety could be observed in a non-clinical sample.

METHOD

Forty-five healthy Spanish-speaking individuals (23 females) were administered a verbal memory task. Lists of high- and low-frequency words were presented. Immediate free recall was requested after the learning of each list, and a yes/no recognition task was completed during the acquisition of the fMRI data.

RESULTS

Regression analyses revealed that higher depression scores in women, and higher anxiety scores in men, were associated with poorer recall. In women, higher depression scores were further associated with decreased cerebral activity in the right temporoparietal junction, left inferior occipitotemporal gyrus, bilateral thalamus, and left anterior cingulate during correct recognition of target words. In men, anxiety scores were not associated with any cerebral activity.

CONCLUSIONS

Subclinical depression in women appears to affect memory efficiency by impacting cerebral regions specifically recruited for the cognitive demands of the task, as well as cerebral regions more generally involved in arousal, decision-making, and emotional regulation. Anxiety in men might impact the encoding memory processes. The results, although preliminary, suggest that gender differences may need to be taken into account when developing strategies for the cognitive and pharmacological remediation of memory impairment.

White Matter Connectivity and Gray Matter Volume Changes Following Donepezil Treatment in Patients With Mild Cognitive Impairment: A Preliminary Study Using Probabilistic Tractography

The donepezil treatment is associated with improved cognitive performance in patients with mild cognitive impairment (MCI), and its clinical effectiveness is well-known. However, the impact of the donepezil treatment on the enhanced white matter connectivity in MCI is still unclear. The purpose of this study was to evaluate the thalamo-cortical white matter (WM) connectivity and cortical thickness and gray matter (GM) volume changes in the cortical regions following donepezil treatment in patients with MCI using probabilistic tractography and voxel-based morphometry. Patients with MCI underwent magnetic resonance examinations before and after 6-month donepezil treatment. Compared with healthy controls, patients with MCI showed decreased WM connectivity of the thalamo-lateral prefrontal cortex, as well as reduced thickness in the medial/lateral orbitofrontal cortices (p < 0.05). The thalamo-lateral temporal cortex connectivity in patients with MCI was negatively correlated with Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog) (r = −0.76, p = 0.01). The average score of the Korean version of the mini-mental state examination (K-MMSE) in patients with MCI was improved by 7.9% after 6-months of donepezil treatment. However, the patterns of WM connectivity and brain volume change in untreated and treated patients were not significantly different from each other, resulting from multiple comparison corrections. These findings will be valuable in understanding the neurophysiopathological mechanism on MCI as a prodromal phase of Alzheimer's disease in connection with brain functional connectivity and morphometric change.

Region-specific brain area reductions and increased cholecystokinin positive neurons in diabetic OLETF rats: implication for anxiety-like behavior

Metabolic disorders can induce psychiatric comorbidities. Both brain and neuronal composition imbalances reportedly induce an anxiety-like phenotype. We hypothesized that alterations of localized brain areas and cholecystokinin (CCK) and parvalbumin (PV) expression could induce anxiety-like behavior in type 2 diabetic Otsuka Long-Evans Tokushima fatty (OLETF) rats. Twenty-week-old OLETF and non-diabetic Long-Evans Tokushima Otsuka (LETO) rats were used. The areas of corticolimbic regions were smaller in OLETF rats. The densities of CCK positive neurons in the lateral and basolateral amygdala, hippocampal cornu ammonis area 2, and prelimbic cortex were higher in OLETF rats. The densities of PV positive neurons were comparable between OLETF and LETO rats. Locomotion in the center zone in the open field test was lower in OLETF rats. These results suggest that imbalances of specific brain region areas and neuronal compositions in emotion-related areas increase the prevalence of anxiety-like behaviors in OLETF rats.

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

Neuroimaging research has shown that patients with obsessive-compulsive disorder (OCD) may present brain structural and functional alterations, but the results across imaging modalities and task paradigms are difficult to reconcile. Are the same brain systems that are structurally different in OCD patients also involved in executive function and emotional processing? To answer this, we conducted separate meta-analyses of voxel-based morphometry studies, executive function functional magnetic resonance imaging (fMRI) studies, and emotional processing fMRI studies. Next, with a multimodal approach (conjunction analysis), we identified the common alterations across meta-analyses. Patients presented increased gray matter volume and hyperactivation in the putamen, but the putamen subregions affected differed depending on the psychological process. Left posterior/dorsal putamen showed hyperactivation during executive processing tasks, while predominantly right anterior/ventral putamen showed hyperactivation during emotional processing tasks. Interestingly, age was significantly associated with increased right putamen volume. Finally, the left dorsolateral prefrontal cortex was hyperactive in both functional domains. Our findings highlight task-specific correlates of brain structure and function in OCD and help integrate a growing literature.

A comparative study of white matter volume between postoperative female-to-male transsexuals and healthy female

Cross-sex hormones in female-to-male (FtM) transsexuals play a crucial role in brain plasticity. Morphological study associated with white matter (WM) volume in postoperative FtM transsexuals receiving cross-sex hormones has not been published yet. This study was performed to discriminate the regional WM volume differences between postoperative FtM transsexuals and female controls using voxel-based morphometry (VBM) and further to assess the correlations between regional volume variations and cross-sex hormones. WM volume was assessed in 12 postoperative FtM transsexuals receiving cross-sex hormones with 16 age-matched female controls. WM volume was processed using SPM8 software with diffeomorphic anatomical registration via an exponentiated Lie algebra (DARTEL) algorithm. Serum sex hormones, including estriol, free testosterone (free-T), estradiol, follicle-stimulating hormone, and luteinizing hormone were measured. Postoperative FtM transsexuals showed significantly (p < 0.05) larger WM volumes in the inferior parietal lobule, postcentral gyrus, and middle temporal gyrus compared with female controls. However, there were no brain areas with larger WM volume in female controls compared with FtM transsexuals. WM volumes of the inferior parietal lobule and middle temporal gyrus in FtM transsexuals were positively correlated with the levels of free-T. This study revealed WM volume change and its correlation with free-T level in postoperative FtM transsexuals. These findings will improve our understanding of the morphometric changes in FtM transsexuals under cross-sex hormone therapy.