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Neuroscience and Biobehavioral Reviews Nov 2021A growing literature has shown associations between socioeconomic disadvantage and neural properties (such as brain structure and function). In this review, we aimed to... (Review)
Review
A growing literature has shown associations between socioeconomic disadvantage and neural properties (such as brain structure and function). In this review, we aimed to synthesize findings on the neural correlates of socioeconomic status (SES) in youth samples across neuroimaging modalities. We also aimed to disentangle the effects of different SES measures (e.g., parent income and education) in our synthesis. We found relatively consistent patterns of positive associations between SES and both volume and cortical surface area of frontal regions, and amygdala, hippocampal, and striatal volume (with most consistent results for composite SES indices). Despite limited longitudinal work, results suggest that SES is associated with developmental trajectories of gray matter structure. Higher SES was also found to be associated with increased fractional anisotropy of some white matter tracts, although there were more null than positive findings. Finally, methodological heterogeneity in brain function and connectivity studies prevented us from making strong inferences. Based on our findings, we make recommendations for future research, discuss the role of mitigating factors, and implications for policy.
Topics: Adolescent; Brain; Hippocampus; Humans; Neuroimaging; Social Class; White Matter
PubMed: 34474050
DOI: 10.1016/j.neubiorev.2021.08.027 -
Brain Imaging and Behavior Jun 2023Microstructural alterations in white matter are evident in obsessive-compulsive disorder (OCD) both in adult and paediatric populations. Paediatric patients go through... (Review)
Review
Microstructural alterations in white matter are evident in obsessive-compulsive disorder (OCD) both in adult and paediatric populations. Paediatric patients go through the process of maturation and thus may undergo different pathophysiology than adult OCD. Findings from studies in paediatric obsessive-compulsive disorder have been inconsistent, possibly due to their small sample size or heterogeneous populations. The aim of this review is to provide a comprehensive overview of white matter structures in paediatric obsessive-compulsive disorder and their correlation with clinical features. Based on PRISMA guidelines, we performed a systematic search on diffusion tensor imaging studies that reported fractional anisotropy, mean diffusivity, radial diffusivity, or axial diffusivity alterations between paediatric patients with obsessive-compulsive disorder and healthy controls using voxel-based analysis, or tract-based spatial statistics. We identified fifteen relevant studies. Most studies reported changes predominantly in the corpus callosum, cingulum, arcuate fasciculus, uncinate fasciculus, inferior longitudinal fasciculus, superior longitudinal fasciculus, inferior fronto-occipital fasciculus, corticospinal tract, forceps minor and major, and the cerebellum in paediatric obsessive-compulsive disorder. These alterations included increased and decreased fractional anisotropy and radial diffusivity, and increased mean and axial diffusivity in different white matter tracts. These changes were associated with obsessive-compulsive disorder symptoms. Moreover, specific genetic polymorphisms were linked with cerebellar white matter changes in paediatric obsessive-compulsive disorder. White matter changes are widespread in paediatric OCD patients. These changes are often associated with symptoms however there are controversies in the direction of changes in some tracts.
Topics: Adult; Humans; Child; Diffusion Tensor Imaging; White Matter; Magnetic Resonance Imaging; Diffusion Magnetic Resonance Imaging; Obsessive-Compulsive Disorder; Anisotropy; Brain
PubMed: 36935464
DOI: 10.1007/s11682-023-00761-x -
GeroScience Apr 2024In the context of a globally aging population, exploring interventions that counteract age-related cognitive decline and cerebral structural alterations is paramount.... (Meta-Analysis)
Meta-Analysis
In the context of a globally aging population, exploring interventions that counteract age-related cognitive decline and cerebral structural alterations is paramount. Among various strategies, physical exercise (PE) emerges as a prevalent activity routinely incorporated in many individuals' lives. This systematic review and meta-analysis aims to elucidate the impact of PE on white matter (WM) integrity and cognitive function in older adults. Data from 581 participants, 312 in the PE intervention group, and 269 in the control group were extracted from nine randomized controlled trials (RCTs) retrieved from databases including PubMed, Embase, Web of Science, and the Cochrane Library. The results indicated a significant improvement in white matter (WM) integrity in individuals engaged in PE, as evidenced by enhanced fractional anisotropy (FA) scores (SMD = 0.4, 95% confidence interval (CI) [0.05, 0.75], P = 0.024). The GRADE assessment revealed a moderate risk. However, no significant associations were found between PE and other metrics such as radial diffusivity (RD), mean diffusivity (MD), white matter volume (WMV), hippocampal volume (HV), and cognitive functions (executive function [EF], memory, processing speed). In conclusion, our study emphasizes the potential neurostructural and cognitive functional benefits of physical exercise for the brain health of older adults.
Topics: Humans; Aged; White Matter; Diffusion Tensor Imaging; Cognition; Brain; Exercise
PubMed: 38108993
DOI: 10.1007/s11357-023-01033-8 -
Neuroinformatics Jan 2021Diffusion MRI is the modality of choice to study alterations of white matter. In past years, various works have used diffusion MRI for automatic classification of...
Diffusion MRI is the modality of choice to study alterations of white matter. In past years, various works have used diffusion MRI for automatic classification of Alzheimer's disease. However, classification performance obtained with different approaches is difficult to compare because of variations in components such as input data, participant selection, image preprocessing, feature extraction, feature rescaling (FR), feature selection (FS) and cross-validation (CV) procedures. Moreover, these studies are also difficult to reproduce because these different components are not readily available. In a previous work (Samper-González et al. 2018), we propose an open-source framework for the reproducible evaluation of AD classification from T1-weighted (T1w) MRI and PET data. In the present paper, we first extend this framework to diffusion MRI data. Specifically, we add: conversion of diffusion MRI ADNI data into the BIDS standard and pipelines for diffusion MRI preprocessing and feature extraction. We then apply the framework to compare different components. First, FS has a positive impact on classification results: highest balanced accuracy (BA) improved from 0.76 to 0.82 for task CN vs AD. Secondly, voxel-wise features generally gives better performance than regional features. Fractional anisotropy (FA) and mean diffusivity (MD) provided comparable results for voxel-wise features. Moreover, we observe that the poor performance obtained in tasks involving MCI were potentially caused by the small data samples, rather than by the data imbalance. Furthermore, no extensive classification difference exists for different degree of smoothing and registration methods. Besides, we demonstrate that using non-nested validation of FS leads to unreliable and over-optimistic results: 5% up to 40% relative increase in BA. Lastly, with proper FR and FS, the performance of diffusion MRI features is comparable to that of T1w MRI. All the code of the framework and the experiments are publicly available: general-purpose tools have been integrated into the Clinica software package ( www.clinica.run ) and the paper-specific code is available at: https://github.com/aramis-lab/AD-ML .
Topics: Aged; Aged, 80 and over; Alzheimer Disease; Brain; Diffusion Magnetic Resonance Imaging; Female; Humans; Image Interpretation, Computer-Assisted; Machine Learning; Male
PubMed: 32524428
DOI: 10.1007/s12021-020-09469-5 -
Neuropsychology Review Sep 2021While converging evidence suggests linguistic roles of white matter tracts, detailed associations between white matter alterations of dual pathways and language... (Meta-Analysis)
Meta-Analysis Review
While converging evidence suggests linguistic roles of white matter tracts, detailed associations between white matter alterations of dual pathways and language abilities remain unknown in aphasic patients. We aimed to verify language functions of dual-pathway tracts from specific domains and investigate the influence of moderators. PubMed, Web of Science, Embase, and CENTRAL were searched for studies published between January 1, 1985 and March 17, 2019. A meta-analysis of 46 studies including 1353 aphasic patients was performed by pooling correlation coefficients between linguistic domains and diffusion metrics of dual-pathway tracts. Among these tracts, the fractional anisotropy (FA) value of the left inferior fronto-occipital fasciculus predominated across most linguistic aspects, showing the strongest correlations with global severity, comprehension, naming and reading ability. The left uncinate fasciculus and inferior longitudinal fasciculus also showed significant FA - comprehension correlations. For syntactic processing, FA values of the left superior longitudinal fasciculus and arcuate fasciculus showed significant positive correlations. Meta-regression revealed no influence of etiology on FA - language correlations, while sex had a moderating effect on the FA - comprehension correlation of the arcuate fasciculus, and age influenced the FA - naming correlation in the superior longitudinal fasciculus. In conclusion, multifunctional characteristics of tracts were revealed in aphasic patients, including broad linguistic associations of the inferior fronto-occipital fasciculus, and repetition and syntactic involvement of the arcuate fasciculus. Language associations of the inferior longitudinal fasciculus and uncinate fasciculus were clarified regarding comprehension subdomains. The insignificant moderating effect of the etiology indicates damage of dual pathways is the common neural mechanism, while sex and age influence the correlation with comprehension and naming ability, respectively, in specific tracts.
Topics: Aphasia; Diffusion Tensor Imaging; Humans; Language Development Disorders; Neural Pathways; White Matter
PubMed: 33656701
DOI: 10.1007/s11065-021-09482-8 -
Brain Imaging and Behavior Oct 2022The pathophysiology of migraine as a headache disorder is still undetermined. Diffusion tensor imaging (DTI) has significantly improved our knowledge about brain... (Review)
Review
The pathophysiology of migraine as a headache disorder is still undetermined. Diffusion tensor imaging (DTI) has significantly improved our knowledge about brain microstructure in this disease. Here, we aimed to systematically review DTI studies in migraine and survey the sources of heterogeneity by investigating diffusion parameter changes associated with clinical characteristics and migraine subtypes. Microstructural changes, as revealed by widespread alteration of diffusion metrics in white matter (WM) tracts, subcortical and cortical regions, were reported by several migraine DTI studies. Specifically, we reported changes in the corpus callosum, thalamic radiations, corona radiata, and brain stem. These alterations showed high variability across migraine cycle phases. Additionally, migraine associated with depressive/anxiety symptoms revealed significant changes in the corpus callosum, internal capsule, and superior longitudinal fasciculus. No significant WM microstructural differences were observed between migraine patients with and without aura. Overall, differences between chronic and episodic migraine showed inconsistency across studies. Migraine is associated with microstructural changes in widespread regions including thalamic radiations, corpus callosum, and brain stem. These alterations can highlight neuronal damage and neuronal plasticity mechanisms either following pain stimulations occurring in migraine cycle or as a compensatory response to pain in chronic migraine. Longitudinal studies applying advanced modalities may shed new light on the underlying microstructural changes in migraine subtypes.
Topics: Humans; Diffusion Tensor Imaging; White Matter; Magnetic Resonance Imaging; Migraine Disorders; Brain; Leukoaraiosis; Pain; Anisotropy
PubMed: 35710680
DOI: 10.1007/s11682-022-00690-1 -
NeuroImage. Clinical 2017Antisocial behavior (AB), including aggression, violence, and theft, is thought be underpinned by abnormal functioning in networks of the brain critical to emotion... (Review)
Review
Antisocial behavior (AB), including aggression, violence, and theft, is thought be underpinned by abnormal functioning in networks of the brain critical to emotion processing, behavioral control, and reward-related learning. To better understand the abnormal functioning of these networks, research has begun to investigate the connections between brain regions implicated in AB using diffusion tensor imaging (DTI), which assesses white-matter tract microstructure. This systematic review integrates findings from 22 studies that examined the relationship between white-matter microstructure and AB across development. In contrast to a prior hypothesis that AB is associated with greater diffusivity specifically in the uncinate fasciculus, findings suggest that adult AB is associated with greater diffusivity across a range of white-matter tracts, including the uncinate fasciculus, inferior fronto-occipital fasciculus, cingulum, corticospinal tract, thalamic radiations, and corpus callosum. The pattern of findings among youth studies was inconclusive with both higher and lower diffusivity found across association, commissural, and projection and thalamic tracts.
Topics: Antisocial Personality Disorder; Diffusion Tensor Imaging; Humans; Neural Pathways; White Matter
PubMed: 28180079
DOI: 10.1016/j.nicl.2017.01.014 -
NeuroImage. Clinical 2016Since the introduction of diffusion tensor imaging, white matter abnormalities in epilepsy have been studied extensively. However, the affected areas reported, the... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Since the introduction of diffusion tensor imaging, white matter abnormalities in epilepsy have been studied extensively. However, the affected areas reported, the extent of abnormalities and the association with relevant clinical parameters are highly variable. We aimed to obtain a more consistent estimate of white matter abnormalities and their association with clinical parameters in different epilepsy types.
METHODS
We systematically searched for differences in white matter fractional anisotropy and mean diffusivity, at regional and voxel level, between people with epilepsy and healthy controls. Meta-analyses were used to quantify the directionality and extent of these differences. Correlations between white matter differences and age of epilepsy onset, duration of epilepsy and sex were assessed with meta-regressions.
RESULTS
Forty-two studies, with 1027 people with epilepsy and 1122 controls, were included with regional data. Sixteen voxel-based studies were also included. People with temporal or frontal lobe epilepsy had significantly decreased fractional anisotropy (Δ -0.021, 95% confidence interval -0.026 to -0.016) and increased mean diffusivity (Δ0.026 × 10 mm/s, 0.012 to 0.039) in the commissural, association and projection white matter fibers. White matter was much less affected in generalized epilepsy. White matter changes in people with focal epilepsy correlated with age at onset, epilepsy duration and sex.
SIGNIFICANCE
This study provides a better estimation of white matter changes in different epilepsies. Effects are particularly found in people with focal epilepsy. Correlations with the duration of focal epilepsy support the hypothesis that these changes are, at least partly, a consequence of seizures and may warrant early surgery. Future studies need to guarantee adequate group sizes, as white matter differences in epilepsy are small.
Topics: Adolescent; Adult; Anisotropy; Brain; Child; Diffusion Tensor Imaging; Epilepsy, Generalized; Female; Humans; Image Interpretation, Computer-Assisted; Magnetic Resonance Imaging; Male; Middle Aged; White Matter; Young Adult
PubMed: 27882296
DOI: 10.1016/j.nicl.2016.10.025 -
JAACAP Open Dec 2023A growing body of literature has focused on the neural mechanisms of depression. Our goal was to conduct a systematic review on the white matter microstructural...
OBJECTIVE
A growing body of literature has focused on the neural mechanisms of depression. Our goal was to conduct a systematic review on the white matter microstructural differences in adolescents with depressive disorders vs adolescents without depressive disorders.
METHOD
We searched PubMed and PsycINFO for publications on August 3, 2022 (original search conducted in July 2021). The review was registered on PROSPERO (registration number: CRD42021268200), and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. Eligible studies were original research papers comparing diffusion tensor/spectrum imaging findings in adolescents with vs without depression (originally ages 12-19 years, later expanded to 11-21 years). Studies were excluded if they focused on depression exclusively in the context of another condition, used only dimensional depressive symptom assessment(s), or used the same dataset as another included publication.
RESULTS
The search yielded 575 unique records, of which 14 full-text papers were included (824 adolescents with depression and 686 without depression). The following white matter regions showed significant differences in fractional anisotropy in at least 3 studies: uncinate fasciculus, cingulum, anterior corona radiata, inferior fronto-occipital fasciculus, and corpus callosum (genu and body). Most studies reported decreased, rather than increased, fractional anisotropy in adolescents with depression. Limitations include the possibility for selective reporting bias and risk of imprecision, given the small sample sizes in some studies.
CONCLUSION
Our systematic review suggests aberrant white matter microstructure in limbic-cortical-striatal-thalamic circuits, and the corpus callosum, in adolescents with depression. Future research should focus on developmental trajectories in depression, identifying sources of heterogeneity and integrating findings across imaging modalities.
PubMed: 38576601
DOI: 10.1016/j.jaacop.2023.08.006 -
Neurological Sciences : Official... May 2024Post-COVID conditions (PCCs) cover a wide spectrum of lingering symptoms experienced by survivors of coronavirus disease 2019 (COVID-19). Neurological and... (Review)
Review
Post-COVID conditions (PCCs) cover a wide spectrum of lingering symptoms experienced by survivors of coronavirus disease 2019 (COVID-19). Neurological and neuropsychiatric sequelae are common in PCCs. Advanced magnetic resonance imaging (MRI) techniques can reveal subtle alterations in brain structure, function, and perfusion that underlie these sequelae. This systematic review aimed to synthesize findings from studies that used advanced MRI to characterize brain changes in individuals with PCCs. A detailed literature search was conducted in the PubMed and Scopus databases to identify relevant studies that used advanced MRI modalities, such as structural MRI (sMRI), diffusion tensor imaging (DTI), functional MRI (fMRI), and perfusion-weighted imaging (PWI), to evaluate brain changes in PCCs. Twenty-five studies met the inclusion criteria, comprising 1219 participants with PCCs. The most consistent findings from sMRI were reduced gray matter volume (GMV) and cortical thickness (CTh) in cortical and subcortical regions. DTI frequently reveals increased mean diffusivity (MD), radial diffusivity (RD), and decreased fractional anisotropy (FA) in white matter tracts (WMTs) such as the corpus callosum, corona radiata, and superior longitudinal fasciculus. fMRI demonstrated altered functional connectivity (FC) within the default mode, salience, frontoparietal, somatomotor, subcortical, and cerebellar networks. PWI showed decreased cerebral blood flow (CBF) in the frontotemporal area, thalamus, and basal ganglia. Advanced MRI shows changes in the brain networks and regions of the PCCs, which may cause neurological and neuropsychiatric problems. Multimodal neuroimaging may help understand brain-behavior relationships. Longitudinal studies are necessary to better understand the progression of these brain anomalies.
Topics: Humans; Diffusion Tensor Imaging; COVID-19; Magnetic Resonance Imaging; Neuroimaging; Brain; Magnetic Resonance Spectroscopy; White Matter
PubMed: 38421524
DOI: 10.1007/s10072-024-07427-6