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Journal of Psychiatry & Neuroscience :... Nov 2020Structural differences associated with depression have not been confirmed in brain regions apart from the hippocampus. Comorbid anxiety has been inconsistently assessed,... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Structural differences associated with depression have not been confirmed in brain regions apart from the hippocampus. Comorbid anxiety has been inconsistently assessed, and may explain discrepancies in previous findings. We investigated the link between depression, comorbid anxiety and brain structure.
METHODS
We followed Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) guidelines (PROSPERO CRD42018089286). We searched the Cochrane Library, MEDLINE, PsycInfo, PubMed and Scopus, from database inception to Sept. 13, 2018, for MRI case-control studies that reported brain volumes in healthy adults and adults with clinical depression. We summarized mean volumetric differences using meta-analyses, and we assessed demographics, depression factors and segmentation procedure as moderators using meta-regressions.
RESULTS
We included 112 studies in the meta-analyses, assessing 4911 healthy participants and 5934 participants with depression (mean age 49.8 yr, 68.2% female). Volume effects were greater in late-onset depression and in multiple episodes of depression. Adults with depression and no comorbidity showed significantly lower volumes in the putamen, pallidum and thalamus, as well as significantly lower grey matter volume and intracranial volume; the largest effects were in the hippocampus (6.8%, p < 0.001). Adults with depression and comorbid anxiety showed significantly higher volumes in the amygdala (3.6%, p < 0.001). Comorbid anxiety lowered depression effects by 3% on average. Sex moderated reductions in intracranial volume.
LIMITATIONS
High heterogeneity in hippocampus effects could not be accounted for by any moderator. Data on symptom severity and medication were sparse, but other factors likely made significant contributions.
CONCLUSION
Depression-related differences in brain structure were modulated by comorbid anxiety, chronicity of symptoms and onset of illness. Early diagnosis of anxiety symptomatology will prove crucial to ensuring effective, tailored treatments for improving long-term mental health and mitigating cognitive problems, given the effects in the hippocampus.
Topics: Adult; Anxiety Disorders; Brain; Comorbidity; Depressive Disorder; Female; Humans; Male; Middle Aged
PubMed: 32726102
DOI: 10.1503/jpn.190156 -
Neurology India 2020The incidence and prevalence of Parkinson's (PD) are increasing rapidly in developing countries. PD is difficult to diagnose based on clinical assessment. Presently,...
The incidence and prevalence of Parkinson's (PD) are increasing rapidly in developing countries. PD is difficult to diagnose based on clinical assessment. Presently, magnetic resonance imaging (MRI) methods such as R2* and Quantitative Susceptibility Mapping (QSM) were found to be useful in diagnosing the PD based on the iron deposition in different regions of the brain. The objective of this review was to evaluate the efficacy of QSM over R2* in assessment of PD. A comprehensive literature search was made on PubMed-Medline, CINAHL, Science Direct, Scopus, Web of Science, and the Cochrane library databases for original research articles published between 2000 and 2018. Original articles that reported the efficacy of QSM and R2* in assessment of PD were included. A total of 327 studies were identified in the literature search. However, only ten studies were eligible for analysis. Of the ten studies, five studies compared the accuracy of QSM over R2* in measuring the iron deposition in different regions of brain in PD. Our review found that QSM has better accuracy in identifying iron deposition in PD patients compared to R2*. However, there is discrepancy in the results between MRI Imaging methods and Postmortem studies. Additional longitudinal research studies are needed to provide a strong evidence base for the use of MRI imaging methods such as R2*and QSM in accurately measuring iron deposition in different regions of brain and serve as biomarkers in PD.
Topics: Brain; Caudate Nucleus; Globus Pallidus; Humans; Iron; Magnetic Resonance Imaging; Parkinson Disease; Putamen; Red Nucleus; Sensitivity and Specificity; Substantia Nigra; Thalamus
PubMed: 32415005
DOI: 10.4103/0028-3886.284377 -
NeuroImage Apr 2020Adolescence is increasingly viewed as a sensitive period in the development of substance use disorders (SUDs). Neurodevelopmental 'dual-risk' theories suggest adolescent... (Meta-Analysis)
Meta-Analysis
Adolescence is increasingly viewed as a sensitive period in the development of substance use disorders (SUDs). Neurodevelopmental 'dual-risk' theories suggest adolescent vulnerability to problematic substance use is driven by an overactive reward drive mediated by the striatum, and poor cognitive control mediated by the prefrontal cortex. To this end, there has been a growing number of neuroimaging studies examining cognitive and affective neural systems during adolescence for markers of vulnerability to problematic substance use. Here, we perform a coordinate-based meta-analysis on this emerging literature. Twenty-two task-based voxelwise fMRI studies with activation differences associated with substance use vulnerability, representative of approximately 1092 subjects, were identified through a systematic literature search (PubMed, Scopus) and coordinates of activation differences (N = 190) were extracted. Adolescents were defined as 'at-risk' for problematic substance use based on a family history of SUD or through prospective prediction of substance use initiation or escalation. Multilevel kernel density analysis was used to identify the most consistent brain regions associated with adolescent substance use vulnerability. Across the included studies, substance use vulnerability was most reliably associated with activation differences in the striatum, where at-risk adolescents had hyper-activation in the dorsal subdivision (putamen). Follow-up analyses suggested striatal differences were driven by tasks sharing a motivational and/or reward component (e.g., monetary incentive) and common across subgroups of substance use risk (family history and prospective prediction studies). Analyses examining the role of psychiatric comorbidity revealed striatal activation differences were significantly more common in samples whose definition of substance use risk included cooccurring externalizing psychopathology. Furthermore, substance use risk meta-analytic results were no longer significant when excluding these studies, although this may reflect limitations in statistical power. No significant activation differences were observed in prefrontal cortex in any analysis. These results suggest striatal dysfunction, rather than prefrontal, may be a more primary neural feature of adolescent vulnerability to problematic substance use, possibly through a dimension of individual variability shared with externalizing psychopathology. However, our systematic literature search confirms this is still an emerging field. More studies, increased data sharing, and further quantitative integration are necessary for a comprehensive understanding of the neuroimaging markers of adolescent substance use risk.
Topics: Adolescent; Adolescent Behavior; Corpus Striatum; Executive Function; Functional Neuroimaging; Humans; Substance-Related Disorders
PubMed: 31875520
DOI: 10.1016/j.neuroimage.2019.116476 -
Clinical Radiology Oct 2019To test the network degeneration hypothesis in multiple sclerosis (MS) with a two-stage coordinate-based meta-analysis by: (1) characterising regional selectivity of... (Meta-Analysis)
Meta-Analysis
AIM
To test the network degeneration hypothesis in multiple sclerosis (MS) with a two-stage coordinate-based meta-analysis by: (1) characterising regional selectivity of grey matter (GM) atrophy and (2) testing for functional connectivity involving these regions.
MATERIALS AND METHODS
Meta-analytic sources included 33 journal articles (1,666 MS patients and 1,269 healthy controls) with coordinate-based results from voxel-based morphometry analysis demonstrating GM atrophy. Mass univariate and multivariate coordinate-based meta-analyses were performed to identify a convergent pattern of GM atrophy and determine inter-regional co-activation (as a surrogate of functional connectivity), with anatomical likelihood estimation and functional meta-analytic connectivity modelling, respectively.
RESULTS
Localised GM atrophy was demonstrated in the thalamus, putamen, caudate, sensorimotor cortex, insula, superior temporal gyrus, and cingulate gyrus. This convergent pattern of atrophy displayed significant inter-regional functional co-activations.
CONCLUSION
In MS, GM atrophy was regionally selective, and these regions were functionally connected. The meta-analytic model-based results of this study are intended to guide future development of quantitative neuroimaging markers for diagnosis, evaluating disease progression, and monitoring treatment response.
Topics: Atrophy; Brain; Gray Matter; Humans; Magnetic Resonance Imaging; Multiple Sclerosis; Neuroimaging
PubMed: 31421864
DOI: 10.1016/j.crad.2019.07.005 -
Journal of Child and Adolescent... Aug 2019Addictive disorders start during adolescence for most individuals, and developmental differences in brain maturation and response to treatments are present. Recent... (Meta-Analysis)
Meta-Analysis
Addictive disorders start during adolescence for most individuals, and developmental differences in brain maturation and response to treatments are present. Recent studies in adults have identified associations between addiction treatment response and regional and circuit specific brain dysfunction, suggesting candidate neural treatment targets. The purpose of this systematic review and meta-analysis was to qualitatively and quantitatively summarize findings from structural and functional neuroimaging studies that examine neural correlates of treatment response in adolescents and young adults with addictive disorders. A systematic review and meta-analysis of peer-reviewed studies was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Studies were selected if they included individuals aged 13-26 with a DSM-IV or DSM-5 () addictive disorder diagnosis, used neuroimaging, administered a treatment/intervention, and reported within- or between-subject contrasts in brain structure or activity across treatment/intervention and a control condition or brain-behavior correlations with treatment-outcome variables. Quantitative meta-analyses used an activation-likelihood estimation (ALE) approach. Out of 3177 citations, 27 studies were included in the qualitative analysis. Qualitative analyses revealed anatomical, connectivity, and functional brain-behavior associations with response to addiction interventions across a broad array of cortical and subcortical brain regions and associated networks. Eighteen functional magnetic resonance imaging studies involving 354 participants and 88 brain foci were included in the ALE meta-analysis. Despite significant heterogeneity in study design and methods, six ALE activation clusters localized to the anterior cingulate cortex, inferior frontal gyrus, supramarginal gyrus, middle temporal gyrus, precuneus, and putamen showed consistent brain-behavior associations with treatment-outcome variables. Cortical and subcortical brain regions involved in cognition, emotion regulation, decision-making, reward, and self-reference are associated with treatment response in addicted youth. These results are consistent with findings in the adult literature and suggest overlapping neural treatment targets across developmental stages.
Topics: Adolescent; Adolescent Behavior; Behavior, Addictive; Brain; Cognition; Decision Making; Functional Neuroimaging; Humans; Reward; Substance-Related Disorders; Young Adult
PubMed: 31313938
DOI: 10.1089/cap.2019.0007 -
Neuropsychopharmacology Reports Sep 2019Altered trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors has been reported in postmortem studies and suggested the involvement of...
BACKGROUND AND OBJECTIVES
Altered trafficking of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors has been reported in postmortem studies and suggested the involvement of AMPA receptors in the pathophysiology underpinning addictive disorders. However, these findings seemed mixed.
METHODS
A systematic literature search was conducted, using PubMed and Embase (last search, August 2018), to identify human postmortem studies that examined the expression of proteins and mRNA of AMPA receptor subunits in patients with addictive disorders in comparison with healthy controls.
RESULTS
Twelve (18 studies) out of 954 articles were identified to be relevant. Eight studies included alcohol use disorders, and four studies included heroin/cocaine abusers. The most frequently investigated regions were the hippocampus (three studies), amygdala (three studies), and putamen (three studies). In summary, two out of the three studies showed an increase in the expression of AMPA receptors in the hippocampus, while the other study found no change. Two studies to examine the amygdala demonstrated either a decreased or no change in receptor expression or binding. Concerning putamen, two studies showed no significant change whereas an overexpression of receptors was observed in the other.
CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE
The hippocampus and amygdala may be pertinent to addictive disorders through their functions on learning and memory, whereas findings in other regions were inconsistent across the studies. Human postmortem studies are prone to degenerative changes after death. Moreover, only qualitative assessment was conducted because of the limited, heterogenous data. These limitations emphasize the need to investigate AMPA receptors in the living human brains.
Topics: Adult; Aged; Amygdala; Autopsy; Female; Hippocampus; Humans; Male; Middle Aged; Protein Binding; Protein Subunits; Putamen; RNA, Messenger; Receptors, AMPA; Substance-Related Disorders
PubMed: 31070872
DOI: 10.1002/npr2.12058