Regional alterations in cortical thickness and white matter integrity in amyotrophic lateral sclerosis

Previous neuroimaging studies have revealed that both gray matter (GM) and white matter (WM) are altered in several morphological aspects in amyotrophic lateral sclerosis (ALS). However, the relations between GM and WM measures and their contributions to clinical features remain in doubt. In this study, we acquired high-resolution diffusion tensor imaging along with structural magnetic resonance imaging data on 20 patients with clinical evidence of ALS and 21 matched healthy controls. WM microstructural metrics and cortical thickness were measured to characterize the whole brain WM and GM degenerative patterns. Probabilistic diffusion tractography was used to reconstruct the tracts from the WM regions characterized by fractional anisotropy (FA) decrease in patients. Decreased FA and increased radial diffusivity was observed in WM regions of the bilateral corticospinal tracts (CST) and callosal motor fibers in the ALS patients, while the superior longitudinal fasciculus exhibited a changing trend. Cortical thinning was found in the anatomically congruent regions, including the motor-related cortices (i.e., bilateral precentral gyri, dorsal premotor cortices, and left supplementary motor area), prefrontal and occipito-parietal regions. However, there was no significant relationship between FA reduction and cortical thinning. Finally, patients with faster clinical progression showed more severe cortical thinning of the left precentral gyrus and FA reduction of the left CST. Together, these findings suggest that ALS is multisystem degeneration involving both the widespread cortices and the underlying WM fibers. GM and WM changes might play distinct roles in the disease progression.     

Voxel-based morphometry study of brain volumetry and diffusivity in amyotrophic lateral sclerosis patients with mild disability

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive and simultaneous degeneration of upper and lower motor neurons. The pathological process associated to ALS, albeit more pronounced in the motor/premotor cortices and along the corticospinal tracts (CST), does not spare extra-motor brain gray (GM) and white (WM) matter structures. However, it remains unclear whether such extra-motor cerebral abnormalities occur with mildly disabling disease, and how irreversible tissue loss and intrinsic tissue damage are interrelated. To this end, we used an optimized version of voxel-based morphometry (VBM) analysis to investigate the patterns of regional GM density changes and to quantify GM and WM diffusivity alterations of the entire brain from mildly disabled patients with ALS. A high-resolution T1-weighted 3D magnetization-prepared rapid acquisition gradient echo and a pulsed gradient spin-echo single shot echo-planar sequence of the brain were acquired from 25 mildly disabled patients with ALS and 18 matched healthy controls. An analysis of covariance was used to compare volumetry and diffusivity measurements between patients and controls. Compared with controls, ALS patients had significant clusters of locally reduced GM density (P < 0.001) in the right premotor cortex, left inferior frontal gyrus (IFG), and superior temporal gyrus (STG), bilaterally. In ALS patients contrasted to controls, we also found significant clusters of locally increased MD (P < 0.001) in the splenium of the corpus callosum and in the WM adjacent to the IFG, STG, and middle temporal gyrus (MTG) of the right hemisphere, and in the WM adjacent to the MTG and lingual gyrus in the left hemisphere. Compared with controls, ALS patients also had significant clusters of locally decreased FA values (P < 0.001) in the CST in the midbrain and corpus callosum, bilaterally. This study supports the notion that ALS is a multisystem disorder and suggests that extra-motor involvement may be an early feature of the disease.     

A multimodal meta-analysis of regional structural and functional brain alterations in type 2 diabetes

Neuroimaging studies have identified brain structural and functional alterations of type 2 diabetes mellitus (T2DM) patients; however, there is no systematic information on the relations between abnormalities in these two domains. We conducted a multimodal meta-analysis of voxel-based morphometry and regional resting-state functional MRI studies in T2DM, including fifteen structural datasets (693 patients and 684 controls) and sixteen functional datasets (378 patients and 358 controls). We found, in patients with T2DM compared to controls, conjoint decreased regional gray matter volume (GMV) and altered intrinsic activity mainly in the default mode network including bilateral superior temporal gyrus/Rolandic operculum, left middle and inferior temporal gyrus, and left supramarginal gyrus; decreased GMV alone in the limbic system; and functional abnormalities alone in the cerebellum, insula, and visual cortex. This meta-analysis identified complicated patterns of conjoint and dissociated brain alterations in T2DM patients, which may help provide new insight into the neuropathology of T2DM.     

A multicentre study of motor functional connectivity changes in patients with multiple sclerosis

In this multicentre study involving eight European centres, we characterized the spatial pattern of functional connectivity (FC) in the sensorimotor network from 61 right-handed patients with multiple sclerosis (MS) and 74 age-matched healthy subjects assessed with the use of functional magnetic resonance imaging (fMRI) and a simple motor task of their right dominant hand. FC was investigated by using: (i) voxel-wise correlations between the left sensorimotor cortex (SMC) and any other area in the brain; and (ii) bivariate correlations between time series extracted from several regions of interest (ROIs) belonging to the sensorimotor network. Both healthy controls and MS patients had significant FC between the left SMC and several areas of the sensorimotor network, including the bilateral postcentral and precentral gyri, supplementary motor area, middle frontal gyri, insulae, secondary somatosensory cortices, thalami, and right cerebellum. Voxel-wise assessment of FC revealed increased connectivity between the left SMC and the right precentral gyrus, right middle frontal gyrus (MFG) and bilateral postcentral gyri in MS patients as compared with controls. ROI analysis also showed a widespread pattern of altered connectivity, characterized by increased FC between the right MFG, the left insula and the right inferior frontal gyrus in comparison with many regions of the sensorimotor network. These results provide further evidence for increased bihemispheric contributions to motor control in patients with MS relative to healthy controls. They further suggest that multicentre fMRI studies of FC changes are possible, and provide a potential imaging biomarker for use in experimental therapeutic studies directed at enhancing adaptive plasticity in the disease.     

Different spatial patterns of brain atrophy and global functional connectivity impairments in major depressive disorder

Alterations in grey matter structure and functional connectivity (FC) are pathological features of major depressive disorder (MDD). However, the relationship between brain structural and functional impairments in MDD remains uncertain. Thus, the aim of this study was to investigate the relationship between alterations in grey matter volume (GMV) and resting-state global functional connectivity density (rs-gFCD) in MDD. Forty-five patients with MDD and 48 healthy controls underwent structural and resting-state functional magnetic resonance imaging (fMRI). GMV and rs-gFCD maps of each subject were created, and the intergroup differences in these neuroimaging metrics were evaluated. Compared to healthy controls, patients with MDD displayed reduced GMV in the left insula, putamen, amygdala and hippocampus (mainly in the limbic system). In contrast, decreased rs-gFCD was observed in the left postcentral and precentral gyri, right fusiform gyrus and lingual gyrus (mainly in the sensory system). Furthermore, we found no significant correlations between GMV and rs-gFCD in these brain regions. Finally, overlap ratio analysis demonstrated that the spatial distribution patterns of intergroup differences on the GMV and rs-gFCD maps were distinct. Our findings suggest that the presence of distinct spatial distribution patterns of brain atrophy and global FC impairments might be pathological features of MDD.     

失独伴慢性创伤后应激障碍患者脑基于体素形态学及功能连接分析

目的:探讨失独伴慢性创伤后应激障碍（posttraumatic stress disorder, PTSD）患者脑灰质体积和功能连接改变及其与PTSD症状的关系。方法:2017年10月至2019年5月共纳入19例伴慢性PTSD失独者（伴PTSD组）、28例不伴PTSD失独者（不伴PTSD组）及27例健康对照者（对照组）...     

Motor and extra-motor gray matter integrity may underlie neurophysiologic parameters of motor function in amyotrophic lateral sclerosis: a combined voxel-based morphometry and transcranial stimulation study

The association between gray matter (GM) density and neurophysiologic changes is still unclear in amyotrophic lateral sclerosis (ALS). We evaluated the relationship between GM density and motor system integrity combining voxel-based morphometry (VBM) and transcranial magnetic stimulation (TMS) in ALS. We included 17 ALS patients and 22 healthy controls (HC) who underwent 3D-T1-weighted imaging. Among the ALS group, we applied left motor cortex single-pulse TMS. We used whole-brain VBM comparing ALS and HC in GM density. We also conducted regression analysis to examine correlations between GM density and the following TMS parameters: motor evoked potential (MEP)/M ratio and central motor conduction time (CMCT). We found significantly decreased GM density in ALS patients in several frontal, temporal, parietal/occipital and cerebellar regions (p?<?0.001 uncorrected; cluster-extent threshold k?=?100 voxels per cluster). With regards to TMS parameters, ALS patients showed mostly increased MEP/M ratio and modest prolongation of CMCT. MEP/M ratio was associated with GM density in (a) rolandic operculum/inferior frontal gyrus/precentral gyrus; anterior cingulate gyrus; inferior temporal gyrus; superior parietal lobule; cuneus; superior occipital gyrus and cerebellum (positive association) and (b) paracentral lobule/supplementary motor area (negative association). CMCT was associated with GM density in (a) inferior frontal gyrus and middle cingulated gyrus (positive association) and (b) superior parietal lobule; cuneus and cerebellum (negative association). Our findings support a significant interaction between motor and extra-motor structural and functional changes and highlight that motor and extra-motor GM integrity may underlie TMS parameters of motor function in ALS patients.     

Structural neuroplasticity in the sensorimotor network of professional female ballet dancers

Evidence suggests that motor, sensory, and cognitive training modulates brain structures involved in a specific practice. Functional neuroimaging revealed key brain structures involved in dancing such as the putamen and the premotor cortex. Intensive ballet dance training was expected to modulate the structures of the sensorimotor network, for example, the putamen, premotor cortex, supplementary motor area (SMA), and the corticospinal tracts. We investigated gray (GM) and white matter (WM) volumes, fractional anisotropy (FA), and mean diffusivity (MD) using magnetic resonance‐based morphometry and diffusion tensor imaging in 10 professional female ballet dancers compared with 10 nondancers. In dancers compared with nondancers, decreased GM volumes were observed in the left premotor cortex, SMA, putamen, and superior frontal gyrus, and decreased WM volumes in both corticospinal tracts, both internal capsules, corpus callosum, and left anterior cingulum. FA was lower in the WM underlying the dancers' left and right premotor cortex. There were no significant differences in MD between the groups. Age of dance commencement was negatively correlated with GM and WM volume in the right premotor cortex and internal capsule, respectively, and positively correlated with WM volume in the left precentral gyrus and corpus callosum. Results were not influenced by the significantly lower body mass index of the dancers. The present findings complement the results of functional imaging studies in experts that revealed reduced neural activity in skilled compared with nonskilled subjects. Reductions in brain activity are accompanied by local decreases in GM and WM volumes and decreased FA. Hum Brain Mapp, 2010. © 2009 Wiley‐Liss, Inc.     

Longitudinal course of cortical thickness decline in amyotrophic lateral sclerosis

To determine longitudinal rates of cortical atrophy in classical Amyotrophic lateral sclerosis (ALS) and ALS variants. Rates of cortical thinning were determined between 2 scans, 3–15 months apart, in 77 ALS patients: 51 classical, 12 upper motor neuron (UMN), and 14 lower motor neuron (LMN) ALS variants. Cortical thickness at the first assessment was compared with 60 healthy controls matched by age and gender. Atrophy rates were compared between patient sub-groups and correlated with disease duration, progression, and severity. Using a cross-sectional analysis, we found a significant difference in cortical thickness between ALS patients and controls in the motor and extra-motor areas (left medial orbito frontal gyrus, left inferior parietal gyrus, bilateral insular cortex, right fusiform gyrus, bilateral precuneus). Using a longitudinal analysis, we found a significant decline of cortical thickness in frontal, temporal, and parietal regions over the course of the study in ALS patients. Effects were independent of the clinical subtype, with exception of the precentral gyrus (p < 0.001). The LMN ALS variants demonstrated the highest rates of cortical thinning in the precentral gyrus, the UMN-dominant subjects exhibited intermediate rates of atrophy, and the classical ALS patients exhibited no such change. Atrophy of the precentral gyrus in classical ALS indicates a floor effect at the first assessment, resulting in a lack of further atrophy over time. Structural loss of the precentral gyrus appears to be an early sign of classical ALS. Over time, patterns of cortical thinning in extra-motor areas can be identified in ALS, regardless of the phenotype.     

Altered cortical gray matter volume and functional connectivity after transcutaneous spinal cord direct current stimulation in idiopathic restless legs syndrome

ObjectiveTo explore the neurophysiological mechanism of clinically effective transcutaneous spinal cord direct current stimulation (tsDCS) on idiopathic restless legs syndrome (RLS), structural magnetic resonance imaging (sMRI), and resting-state functional MRI (rs-fMRI) were applied to reveal the structural and functional changes in idiopathic RLS patients after tsDCS.MethodsThirty idiopathic RLS patients and 20 gender- and age-matched healthy controls (HC) were enrolled. All patients were randomly divided into anodal treatment group and sham treatment group and were treated with tsDCS for 2 weeks. The international RLS Rating Scale (IRLS-RS) and Pittsburgh Sleep Quality Index (PSQI) were used to evaluate the severity of RLS and sleep quality respectively. The sMRI and rs-fMRI data of anodal treatment group and HC were collected. Voxel-based morphology (VBM) and resting-state functional connectivity analysis were used to assess the change of cortical gray matter volume (GMV) and corresponding functional connectivity (FC) respectively in anodal treatment group after tsDCS treatment.ResultsSham treatment group showed no significant change in IRLS-RS and PSQI scores after tsDCS, while significant decrease scores were observed in anodal treatment group, and the improvement sustained up to 2 weeks. Anodal treatment group showed significant regional decrease of GMV in bilateral cuneus compared to the HC. After tsDCS treatment, the GMV in the bilateral cuneus and left ventral post central gyrus (PoCG_L) decreased significantly. The FC between bilateral cuneus and left primary visual cortex (V1_L), and between right cuneus (Cune_R) and right lingual gyrus (LG_R) increased significantly after tsDCS, whereas the FC between PoCG_L and supplementary motor area (SMA) decreased significantly. The changed FC between PoCG_L and SMA, between Cune_R and V1_L were correlated with the changed IRLS-RS.ConclusionDisturbance of sensorimotor network and visual processing network may be involved in the pathogenesis of RLS. tsDCS probably can regulate FC in the sensorimotor cortex and visual processing cortex to relieve the symptom of RLS. Continuous tsDCS may improve the symptoms of RLS patients for a long time. tsDCS probably could provide a potential non-pharmacologic treatment for idiopathic RLS patients.     

Structural deficits in the emotion circuit and cerebellum are associated with depression, anxiety and cognitive dysfunction in methadone maintenance patients: a voxel-based morphometric study

Heroin users on methadone maintenance treatment (MMT) have elevated rates of co-morbid depression and are associated with have higher relapse rates for substance abuse. Structural abnormalities in MMT patients have been reported, but their impact on clinical performance is unknown. We investigated differences in gray matter volume (GMV) between 27 MMT patients and 23 healthy controls with voxel-based morphometry, and we correlated findings in the patients with Beck Depression Inventory scores, Beck Anxiety Inventory scores, and diminished cognitive functioning. MMT patients exhibited higher emotional deficits than healthy subjects. There was significantly smaller GMV in multiple cortices, especially in the left inferior frontal gyrus and left cerebellar vermis in the MMT group. The smaller GMV in the pre-frontal cortices, left sub-callosal cingulate gyrus, left post-central gyrus, left insula, and right cerebellar declive correlated with higher depression scores. The smaller GMV in the pre-frontal cortices, left sub-callosal cingulate gyrus, and left postcentral gyrus also correlated with higher anxiety scores, while smaller GMV in the cerebellum and bilateral insula was associated with impaired performance on tests of executive function. These results reveal that MMT patients have low GMV in brain regions that are hypothesized to influence cognition and emotion, and the GMV findings might be involved comorbid disorders in the MMT group.     

Neuroanatomical abnormalities in schizophrenia: a multimodal voxelwise meta-analysis and meta-regression analysis

Despite an increasing number of published voxel based morphometry studies of schizophrenia, there has been no adequate attempt to examine gray (GM) and white matter (WM) abnormalities and the heterogeneity of published findings. In the current article, we used a coordinate based meta-analysis technique to simultaneously examine GM and WM abnormalities in schizophrenia and to assess the effects of gender, chronicity, negative symptoms and other clinical variables. 79 studies meeting our inclusion criteria were included in the meta-analysis. Schizophrenia was associated with GM reductions in the bilateral insula/inferior frontal cortex, superior temporal gyrus, anterior cingulate gyrus/medial frontal cortex, thalamus and left amygdala. In WM analyses of volumetric and diffusion-weighted images, schizophrenia was associated with decreased FA and/or WM in interhemispheric fibers, anterior thalamic radiation, inferior longitudinal fasciculi, inferior frontal occipital fasciculi, cingulum and fornix. Male gender, chronic illness and negative symptoms were associated with more severe GM abnormalities and illness chronicity was associated with more severe WM deficits. The meta-analyses revealed overlapping GM and WM structural findings in schizophrenia, characterized by bilateral anterior cortical, limbic and subcortical GM abnormalities, and WM changes in regions including tracts that connect these structures within and between hemispheres. However, the available findings are biased towards characteristics of schizophrenia samples with poor prognosis.     

Resting‐state functional MRI: Functional connectivity analysis of the visual cortex in primary open‐angle glaucoma patients

Purpose: To analyze functional connectivity (FC) of the visual cortex using resting‐state functional MRI in human primary open‐angle glaucoma (POAG) patients. Materials and Methods: Twenty‐two patients with known POAG and 22 age‐matched controls were included in this IRB‐approved study. Subjects were evaluated by 3 T MR using resting‐state blood oxygenation level dependent and three‐dimensional brain volume imaging (3D‐BRAVO) MRI. Data processing was performed with standard software. FC maps were generated from Brodmann areas (BA) 17/18/19/7 in a voxel‐wise fashion. Region of interest analysis was used to specifically examine FC among each pair of BA17/18/19/7. Results: Voxel‐wise analyses demonstrated decreased FC in the POAG group between the primary visual cortex (BA17) and the right inferior temporal, left fusiform, left middle occipital, right superior occipital, left postcentral, right precentral gyri, and anterior lobe of the left cerebellum. Increased FC was found between BA17 and the left cerebellum, right middle cerebellar peduncle, right middle frontal gyrus, and extra‐nuclear gyrus (P < 0.05). In terms of the higher visual cortices (BA18/19), positive FC was disappeared with the cerebellar vermis, right middle temporal, and right superior temporal gyri (P < 0.05). Negative FC was disappeared between BA18/19 and the right insular gyrus (P < 0.05). Region of interest analysis demonstrated no statistically significant differences in FC between the POAG patients relative to the controls (P > 0.05). Conclusion: Changes in FC of the visual cortex are found in patients with POAG. These include alterations in connectivity between the visual cortex and associative visual areas along with disrupted connectivity between the primary and higher visual areas. Hum Brain Mapp 34:2455–2463, 2013. © 2012 Wiley Periodicals, Inc.     

Localization of Motor Areas Adjacent to Arteriovenous Malformations: A Positron Emission Tomographic Study

Motor cortex activity was localized with positron emission tomography (PET) in 4 patients with large arteriovenous malformations adjacent to or undercutting the left primary motor cortex. Relative cerebral blood flow responses were measured during execution of a visually guided motor tracking task performed with the right index finger, hand, great toe, tongue, or eyes alone (control) and mapped onto each patient's corresponding magnetic resonance imaging (MRI) scan. The relative cerebral blood flow responses in the contralateral precentral gyrus, adjacent to each arteriovenous malformation, demonstrated a normal somatotopic distribution, similar to that in a control population. In the 3 patients with preserved motor function, responses were also present in the ipsilateral primary motor cortex, bilateral supplementary motor area, and ipsilateral anterior cerebellum, similar in location to those of a control population. In the fourth patient with a hemiparesis, responses were attenuated in the primary motor cortex, increased in the supplementary motor area, and absent in the cerebellum. The results demonstrate that PET cerebral blood flow mapping can localize motor cortex despite the presence of significant blood flow abnormalities in adjacent arteriovenous malformations. The method, particularly when combined with MRI, may be used in the planning of surgical, radiation, or embolization therapy.     

Low signal intensity in motor cortex on susceptibility-weighted MR imaging is correlated with clinical signs of amyotrophic lateral sclerosis: a pilot study

There is no reliable objective indicator for upper motor neuron dysfunction in amyotrophic lateral sclerosis (ALS). To determine the clinical significance and potential utility of magnetic resonance (MR) signals, we investigated the relationship between clinical symptoms and susceptibility changes in the motor cortex measured using susceptibility-weighted MR imaging taken by readily available 3-T MRI in clinical practice. Twenty-four ALS patients and 14 control subjects underwent 3-T MR T1-weighted imaging and susceptibility-weighted MR imaging with the principles of echo-shifting with a train of observations (PRESTO) sequence. We analysed relationships between relative susceptibility changes in the motor cortex assessed using voxel-based analysis (VBA) and clinical scores, including upper motor neuron score, ALS functional rating scale revised score, and Medical Research Council sum score on physical examination. Patients with ALS exhibited significantly lower signal intensity in the precentral gyrus on susceptibility-weighted MR imaging compared with controls. Clinical scores were significantly correlated with susceptibility changes. Importantly, the extent of the susceptibility changes in the bilateral precentral gyri was significantly correlated with upper motor neuron scores. The results of our pilot study using VBA indicated that low signal intensity in motor cortex on susceptibility-weighted MR imaging may correspond to clinical symptoms, particularly upper motor neuron dysfunction. Susceptibility-weighted MR imaging may be a useful diagnostic tool as an objective indicator of upper motor neuron dysfunction.     

MRI Predicts Efficacy of Constraint-Induced Movement Therapy in Children With Brain Injury

Using resting state (RS) functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI), we identified the predictors of clinical improvement following constraint-induced movement therapy (CIMT) in pediatric patients with chronic hemiplegia.From 14 children with congenital or acquired brain injury and 10 sex- and age-matched healthy controls, brain dual-echo, DTI and RS fMRI sequences were acquired before CIMT. The Quality of Upper Extremities Skills Test and the Gross Motor Function Measure (GMFM) were administered at baseline, at the end of CIMT (10 weeks), and after 6 months. Mean diffusivity and fractional anisotropy (FA) were measured in the lesion responsible for the clinical symptomatology, the affected and unaffected corticospinal tract (CST), motor transcallosal fibers, and uncinate fasciculus (as an internal control). Independent component analysis was used to identify the sensorimotor RS network. The ability of baseline MRI variables to predict clinical changes over time was assessed using multivariate linear models. At baseline, patients had increased mean diffusivity in the symptomatic lesion and decreased FA in the symptomatic lesion, affected corticospinal tract, and motor transcallosal fibers. A reduced RS functional connectivity was found in the bilateral cerebellum, left precentral gyrus, and right secondary sensorimotor cortex. At follow up, Quality of Upper Extremities Skills Test and GMFM scales improved significantly. Baseline average lesion FA predicted clinical improvement at week 10, and baseline functional connectivity of the right secondary sensorimotor cortex and cerebellum predicted GMFM improvement at month 6. DTI and RS fMRI offer promising and objective markers to predict clinical outcomes following CIMT in pediatric patients with congenital or acquired hemiplegia.     

Altered intra- and interregional synchronization in the absence of the corpus callosum: a resting-state fMRI study

Agenesis of the corpus callosum (AgCC) can result in subtle to severe cognitive deficits. Individuals with impaired cognition often show abnormalities on resting-state functional magnetic resonance imaging (rs-fMRI). This study used rs-fMRI to investigate changes in regional homogeneity (ReHo) and functional connectivity (FC) among individuals with AgCC. AgCC individuals (n = 10) and age-, sex-, and education-matched healthy control subjects (n = 19) were included in this study. The ReHo values were calculated to represent spontaneous brain activity. The regions which showed altered ReHo were selected as seeds to compare FC with the whole brain between the AgCC group and the healthy control group. Compared with healthy control subjects, the AgCC individuals had increased ReHo in the left anterior cingulate gyrus, left rolandic operculum, and right precuneus and decreased ReHo in the right calcarine, right cingual gyrus and right cuneus gyrus. The right calcarine and the right lingual gyrus in the AgCC exhibited decreased FC with bilateral cuneus, superior occipital gyrus, Rolandic operculum, superior temporal gyrus, posterior central gyrus, and midcingulate gyrus.The right cuneus gyrus in the AgCC individuals exhibited decreased FC with the bilateral calcarine gyrus, left cuneus, and left superior occipital gyrus. Our study revealed several subareas within the visual cortex exhibited remarkable abnormalities of spontaneous brain activity and decreased FC with the higher-order cognitive cortex.The abnormalities of ReHo and FC in AgCC individuals may provide new insights into the neurological pathophysiology.     

Meta-analytic investigations of common and distinct grey matter alterations in youths and adults with obsessive-compulsive disorder

Obsessive-compulsive disorder (OCD) is a disabling illness with onset generally in childhood. OCD-youths differ from OCD-adults with regard to gender distribution, comorbidity patterns and treatment options. However, little is known about the neural correlate differences underpin those two populations. The current meta-analysis summarizes voxel based morphometry findings to elucidate whether differences of neural correlates exist between these two populations. Both OCD-youths and OCD-adults demonstrated greater striatal volume and smaller prefrontal grey matter volume (GMV). However, smaller GMV in left visual cortex was observed in OCD-youths only, while smaller GMV in anterior cingulate gyrus and greater GMV in cerebellum were demonstrated only in OCD-adults. Meta-regression showed greater GMV in left putamen was most prominent in samples with higher percentages of medicated OCD-adults. Our findings confirmed the most consistent GMV alterations in OCD were in prefrontal-striatal circuitry. Besides, other regions may involve at different developmental stages including deficits of visual cortex in OCD-youths and abnormalities of limbic-cerebellar circuit in OCD-adults. Medication effect may be more pronounced in the striatum, especially the putamen.     

A multiparametric evaluation of regional brain damage in patients with primary progressive multiple sclerosis

The purpose of this study is to define the topographical distribution of gray matter (GM) and white matter (WM) damage in patients with primary progressive multiple sclerosis (PPMS), using a multiparametric MR‐based approach. Using a 3 Tesla scanner, dual‐echo, 3D fast‐field echo (FFE), and diffusion tensor (DT) MRI scans were acquired from 18 PPMS patients and 17 matched healthy volunteers. An optimized voxel‐based (VB) analysis was used to investigate the patterns of regional GM density changes and to quantify GM and WM diffusivity alterations of the entire brain. In PPMS patients, GM atrophy was found in the thalami and the right insula, while mean diffusivity (MD) changes involved several cortical‐subcortical structures in all cerebral lobes and the cerebellum. An overlap between decreased WM fractional anisotropy (FA) and increased WM MD was found in the corpus callosum, the cingulate gyrus, the left short temporal fibers, the right short frontal fibers, the optic radiations, and the middle cerebellar peduncles. Selective MD increase, not associated with FA decrease, was found in the internal capsules, the corticospinal tracts, the superior longitudinal fasciculi, the fronto‐occipital fasciculi, and the right cerebral peduncle. A discrepancy was found between regional WM diffusivity changes and focal lesions because several areas had DT MRI abnormalities but did not harbor T2‐visible lesions. Our study allowed to detect tissue damage in brain areas associated with motor and cognitive functions, which are known to be impaired in PPMS patients. Combining regional measures derived from different MR modalities may be a valuable tool to improve our understanding of PPMS pathophysiology. Hum Brain Mapp 2009. © 2009 Wiley‐Liss, Inc.     

Regional Homogeneity Brain Alterations in Schizophrenia: An Activation Likelihood Estimation Meta-Analysis

ObjectiveResting state functional magnetic resonance imaging (rsfMRI) provides a lot of evidence for local abnormal brain activity in schizophrenia, but the results are not consistent. Our aim is to find out the consistent abnormal brain regions of the patients with schizophrenia by using regional homogeneity (ReHo), and indirectly understand the degree of brain damage of the patients with drug-naive first episode schizophrenia (Dn-FES) and chronic schizophrenia. MethodsWe performed the experiment by activation likelihood estimation (ALE) software to analysis the differences between people with schizophrenia group (all schizophrenia group and chronic schizophrenia group) and healthy controls. ResultsThirteen functional imaging studies were included in quantitative meta-analysis. All schizophrenia group showed decreased ReHo in bilateral precentral gyrus (PreCG) and left middle occipital gyrus (MOG), and increased ReHo in bilateral superior frontal gyrus (SFG) and right insula. Chronic schizophrenia group showed decreased ReHo in bilateral MOG, right fusiform gyrus, left PreCG, left cerebellum, right precuneus, left medial frontal gyrus and left anterior cingulate cortex (ACC). No significant increased brain areas were found in patients with chronic schizophrenia. ConclusionOur findings suggest that patients with chronic schizophrenia have more extensive brain damage than FES, which may contribute to our understanding of the progressive pathophysiology of schizophrenia.