Gray Matter Volume In Children Research Articles

Alterations of brain gray matter volume in children with obstructive sleep apnea.

Obstructive sleep apnea (OSA) seriously affects the children's cognitive functions, but the neuroimaging mechanism of cognitive impairment is still unclear. The purpose of our study was to explore the difference in brain local gray matter volume (GMV) between children with OSA and non-OSA, and the correlation between the difference regions of brain gray matter volume and cognitive, the severity of OSA. Eighty-three children aged 8-13 years were recruited in our study, 52 children were diagnosed as OSA by polysomnography, and 31 as the non-OSA. All the subjects were underwent high-resolution 3-dimensional T1-weighted magnetic resonance images. The voxel-based morphometry (VBM) was be used to analyse the local GMV. The Das-Naglieri cognitive assessment system (DN: CAS) was used to assess the subjects' cognitive. The difference of local GMV between the two groups was analyzed by two-sample T-test. The PSG variables and the scores of DN: CAS between the OSA group and non-OSA group were compared by independent samples t-tests. Pearson correlation was used to calculate the association between the difference areas of gray matter volumes in brain and DN: CAS scores, obstructive apnea/hypopnea index (OAHI, an index of the severity of OSA). The gray matter volume of the right Middle Frontal Gyrus (MFG_R) in OSA children were larger than the non-OSA children, and the OSA children had lower scores of the Word Series in DN: CAS. There was negative correlation between the scores of Expressive Attention in DN: CAS and the gray matter volume of the right middle frontal gyrus, and it was no significantly correlation between OAHI and the gray matter volume of the right middle frontal gyrus. Our results suggest that the development of gray matter volume in frontal cortex, which associated with attention, were sensitive to the effects of OSA, provides neuroimaging evidence for cognitive impairment in children with OSA.

Absence of associations with prefrontal cortex and cerebellum may link to early language and social deficits in preschool children with ASD.

Autism spectrum disorder (ASD) is a complex developmental disorder, characterized by language and social deficits that begin to appear in the first years of life. Research in preschool children with ASD has consistently reported increased global brain volume and abnormal cortical patterns, and the brain structure abnormalities have also been found to be clinically and behaviorally relevant. However, little is known regarding the associations between brain structure abnormalities and early language and social deficits in preschool children with ASD. In this study, we collected magnetic resonance imaging (MRI) data from a cohort of Chinese preschool children with and without ASD (24 ASD/20 non-ASD) aged 12-52 months, explored group differences in brain gray matter (GM) volume, and examined associations between regional GM volume and early language and social abilities in these two groups, separately. We observed significantly greater global GM volume in children with ASD as compared to those without ASD, but there were no regional GM volume differences between these two groups. For children without ASD, GM volume in bilateral prefrontal cortex and cerebellum was significantly correlated with language scores; GM volume in bilateral prefrontal cortex was significantly correlated with social scores. No significant correlations were found in children with ASD. Our data demonstrate correlations of regional GM volume with early language and social abilities in preschool children without ASD, and the absence of these associations appear to underlie language and social deficits in children with ASD. These findings provide novel evidence for the neuroanatomical basis associated with language and social abilities in preschool children with and without ASD, which promotes a better understanding of early deficits in language and social functions in ASD.

Cognitive and Brain Gray Matter Changes in Children with Obstructive Sleep Apnea: A Voxel-Based Morphological Study.

To explore the neural difference between children with obstructive sleep apnea (OSA) and healthy controls, together with the relation between this difference and clinical severity indicator of children with OSA. Twenty-seven children with OSA (7.6 ± 2.5 years, apnea hypopnea index [AHI]: 9.7 ± 5.3 events/h) and 30 healthy controls (7.8 ± 2.6 years, AHI: 1.7 ± 1.2 events/h) were recruited and matched with age, gender, and handedness. All children underwent 3.0 T magnetic resonance imaging of the brain and cognitive testing evaluating. Volumetric segmentation of cortical and subcortical structures and voxel-based morphometry were performed. Pearson's correlation analysis was performed between these features of gray matter volume (GMV) and obstructive apnea index (OAI) among children with OSA. In the comparison of children's Wechsler test scores of full-scale intelligence quotient and verbal intelligence quotient, the OSA group was significantly lower than the control group (p < 0.05). Compared with the control group, the GMV of many brain regions in the OSA group was significantly decreased (p < 0.05). In the correlation analysis of GMV and OAI in OSA group, right inferior frontal gyrus volume was significantly negatively correlated with OAI (r = - 0.49, p = 0.02). Children with OSA presented abnormal neural activities in some brain regions and impaired cognitive functions. This finding suggests an association between the OSA and decreased GMV in children.

Right Fusiform Gray Matter Volume in Children with Long-Term Abacus Training Positively Correlates with Arithmetic Ability

Abacus-based mental calculation (AMC) training has a positive effect on number-related cognitive abilities. While visuospatial strategy may distinguish AMC from conventional calculation method, the underlying neural mechanism is still elusive. The current study aimed to address this question by examining the plasticity of fusiform induced by AMC training and whether this training affects the association between the volume of fusiform and behavioral performance in numerical cognitive tasks using voxel-based morphometry analysis. The results showed that gray matter volumes of bilateral fusiform were significantly smaller in the AMC group relative to the control group. In addition, the volume of right fusiform was positively correlated with digit memory span and negatively correlated with reaction time of an arithmetic operation task only within the AMC group. These results indicate that bilateral fusiform may be the essential neural substrate for AMC experts to recognize and reconstruct abacus-based representations for numbers. These results may advance our understanding of the neural mechanisms of AMC and shield some lights to potential interactions between brain development and cognitive training in children.

Obesity is associated with decreased gray matter volume in children: a longitudinal study.

Childhood obesity has become a global health problem. Previous studies showed that childhood obesity is associated with brain structural differences relative to controls. However, few studies have been performed with longitudinal evaluations of brain structural developmental trajectories in childhood obesity. We employed voxel-based morphometry (VBM) analysis to assess gray matter (GM) volume at baseline and 2-year follow-up in 258 obese children (OB) and 265 normal weight children (NW), recruited as part of the National Institutes of Health Adolescent Brain and Cognitive Development study. Significant group × time effects on GM volume were observed in the prefrontal lobe, thalamus, right precentral gyrus, caudate, and parahippocampal gyrus/amygdala. OB compared with NW had greater reductions in GM volume in these regions over the 2-year period. Body mass index (BMI) was negatively correlated with GM volume in prefrontal lobe and with matrix reasoning ability at baseline and 2-year follow-up. In OB, Picture Test was positively correlated with GM volume in the left orbital region of the inferior frontal gyrus (OFCinf_L) at baseline and was negatively correlated with reductions in OFCinf_L volume (2-year follow-up vs. baseline). These findings indicate that childhood obesity is associated with GM volume reduction in regions involved with reward evaluation, executive function, and cognitive performance.

Altered gray matter volume in children with newly diagnosed type 1 diabetes mellitus.

Type 1 diabetes mellitus (T1DM) affects the development of cognitive function in children, which may be due to deficits in brain structures or functions. It is unclear whether children with T1DM experience alterations in the gray matter (GM) structure at the initial stages of the disease. This study investigated GM structure alterations in children with newly diagnosed T1DM. Based on 3D T1-weighted MR images, we investigated the gray matter volume (GMV) of 35 newly diagnosed T1DM children and 35 age- and sex-matched healthy controls using voxel-based morphometry. The brain regions with significant differences in GMV between the newly diagnosed T1DM children and the controls were extracted and the correlation with clinical data was assessed. Compared with the control group, children with newly diagnosed T1DM had a lower GMV in the right inferior and middle temporal gyri, right lingual gyrus, and left superior frontal gyrus. In T1DM subjects, the GMV of the right middle temporal gyrus was positively correlated with IQ but was negatively correlated with HbA1c. Our findings provide compelling evidence that GM abnormalities occur during early disease stages in T1DM children, which may be a potential neurobiological mechanism underlying cognitive deficits. Using an efficient method to analyze gray matter changes in T1DM is very important. The anterior, posterior, and temporal brain regions are susceptible to T1DM in children. Recent glucose variability may affect regional gray matter volume in children with newly diagnosed T1DM. Structural changes were documented in the gray matter of the brain even at the early stages of the disease in children with T1DM.

General and Specific Factors of Environmental Stress and Their Associations With Brain Structure and Dimensions of Psychopathology

BackgroundEarly-life stressors can adversely affect the developing brain. While hierarchical modeling has established the existence of a general factor of psychopathology, no studies have modeled a general factor of environmental stress and related this factor to brain development. Using a large sample of children from the ABCD (Adolescent Brain Cognitive Development) Study, the current study aimed to identify general and specific factors of environmental stress and test their associations with brain structure and psychopathology. MethodsIn a sample of 11,878 children, bifactor modeling and higher-order (second-order) modeling identified general and specific factors of environmental stress: family dynamics, interpersonal support, neighborhood socioeconomic status deprivation, and urbanicity. Structural equation modeling was performed to examine associations between these factors and regional gray matter volume (GMV) and cortical thickness as well as general and specific factors of psychopathology. ResultsThe general environmental stress factor was associated with globally smaller cortical and subcortical GMV as well as thinner cortices across widespread regions. Family dynamics and neighborhood socioeconomic status deprivation were associated with smaller GMV in focal regions. Urbanicity was associated with larger cortical and subcortical GMV and thicker cortices in frontotemporal regions. The environmental factors were associated with psychopathology in the expected directions. The general factors of environmental stress and psychopathology were both predictors of smaller GMV in children, while remaining distinct from each other. ConclusionsThis study reveals a unifying model of environmental influences that illustrates the inherent organization of environmental stressors and their relationship to brain structure and psychopathology.

Sex differences in medial prefrontal and parietal cortex structure in children with disruptive behavior

Sex differences in brain structure in children with disruptive behavior disorders (DBD) remain poorly understood. This study examined sex differences in gray matter volume in children with DBD in a priori regions-of-interest implicated in the pathophysiology of disruptive behavior. We then conducted a whole-brain analysis of cortical thickness to examine sex differences in regions not included in our hypothesis. Exploratory analyses investigated unique associations between structure, and dimensional measures of severity of disruptive behavior and callous-unemotional traits. This cross-sectional study included 88 children with DBD (30 females) aged 8–16 years and 50 healthy controls (20 females). Structural MRI data were analyzed using surface-based morphometry to test for interactions between sex and group. Multiple-regression analyses tested for sex-specific associations between structure, callous-unemotional traits, and disruptive behavior severity. Boys with DBD showed reduced gray matter volume in the left ventromedial prefrontal cortex (vmPFC) and reduced cortical thickness in the supramarginal gyrus, but not girls compared to respective controls. Dimensional analyses revealed associations between sex, callous-unemotional traits, and disruptive behavior for amygdala and vmPFC volume, and ventrolateral prefrontal cortex cortical thickness. Sex-specific differences in prefrontal structures involved in emotion regulation may support identification of neural biomarkers of disruptive behavior to inform target-based treatments.

Morphological changes of the cerebral cortex between children with isolated growth hormone deficiency and idiopathic short stature

The growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis plays an important role in normal brain development, and GH deficiency inevitably affects the growth of the cerebral cortex. This study was designed to analyze morphological differences in gray matter volume, cortical surface area, and gray matter thickness between children with isolated growth hormone deficiency (IGHD) and children with idiopathic short stature (ISS). Twenty-four children with IGHD (mean age 9.42 years, peak GH < 5 μg/l) and 24 controls with ISS (mean age 9.21 years, peak GH > 10 μg/l) were included. High-resolution three-dimensional T1-weighted MRIs were acquired at participants’ first visit. Measurements of gray matter volume, cortical surface area and gray matter thickness were obtained using FreeSurfer. The total and regional differences between groups were statistically analyzed. Correlations between the FreeSurfer results and GH and IGF-I levels were also obtained. The gray matter volume, cortical surface area and gray matter thickness of the total brain and of the bilateral hemispheres of children with IGHD were significantly smaller than those of children with ISS (all P values < 0.05). All the measurements had similar cortical distributions between groups but varied across regions. Cortical regions with significant differences in the mean gray matter volume and surface area were mainly distributed around the bilateral central sulci and the lateral and basal parts of the temporal lobes (all P values < 0.05). There were negative correlations between gray matter volume, cortical surface area and GH levels, and the right hemispheric and total cortical surface area correlated significantly with GH levels (all P values < 0.05) in children with IGHD. There were significant positive correlations between gray matter volume, cortical surface area and IGF-I levels (all P values < 0.05) in both groups, except for in left hemispheric gray matter volume in children with ISS. Children with IGHD have significant morphological changes in the cerebral cortex, which were partially influenced by GH and IGF-I levels. These cortical changes may be related to deficits in their relatively slower development in intelligence, motor performance, and other functions.

Associations of sleep with gray matter volume and their implications for academic achievement, executive function and intelligence in children with overweight/obesity.

Children with overweight/obesity have poorer sleep and smaller gray matter volume (GMV) than normal-weight children. No studies have investigated the associations of objectively-assessed sleep and GMV in children with overweight/obesity, or their implications for academic and cognitive outcomes. To explore the associations of sleep behaviors with GMV in the whole brain and particularly the hippocampus as a region of interest independent of sedentary time (SED) and physical activity; and to assess whether GMV in the associated regions was related to academic achievement, executive function and intelligence quotient (IQ). Ninety-six children with overweight/obesity (10 ± 1 year) were included. Sleep behaviors were assessed with accelerometers. GMV was acquired by magnetic resonance imaging. Academic achievement, executive function and IQ were assessed with separate tests. Analyses were adjusted for sex, peak height velocity and parent education as well as SED and physical activity. Earlier wake time, less time in bed, wakening after sleep onset (WASO) and WASO occurrences were associated with higher GMV in eight cortical brain regions (k:56-448, P's < .001). Longer total sleep time, higher sleep efficiency and less WASO time were associated with higher GMV in the right hippocampus (β:0.187-0.220, P's < .05). The inferior temporal, fusiform, supramarginal, and postcentral gyri, the superior parietal cortex, precuneus and hippocampus associated with academic achievement and/or IQ. Associations remained after adjustments for SED and physical activity. Sleep behaviors are associated with GMV in multiple cortical regions including the right hippocampus in children with overweight/obesity, which in turn, were associated with academic achievement and IQ.

Linking Lysosomal Enzyme Targeting Genes and Energy Metabolism with Altered Gray Matter Volume in Children with Persistent Stuttering

Developmental stuttering is a childhood onset neurodevelopmental disorder with an unclear etiology. Subtle changes in brain structure and function are present in both children and adults who stutter. It is a highly heritable disorder, and 12–20% of stuttering cases may carry a mutation in one of four genes involved in intracellular trafficking. To better understand the relationship between genetics and neuroanatomical changes, we used gene expression data from the Allen Institute for Brain Science and voxel-based morphometry to investigate the spatial correspondence between gene expression patterns and differences in gray matter volume between children with persistent stuttering (n = 26, and 87 scans) and their fluent peers (n = 44, and 139 scans). We found that the expression patterns of two stuttering-related genes (GNPTG and NAGPA) from the Allen Institute data exhibited a strong positive spatial correlation with the magnitude of between-group gray matter volume differences. Additional gene set enrichment analyses revealed that genes whose expression was highly correlated with the gray matter volume differences were enriched for glycolysis and oxidative metabolism in mitochondria. Because our current study did not examine the participants’ genomes, these results cannot establish the direct association between genetic mutations and gray matter volume differences in stuttering. However, our results support further study of the involvement of lysosomal enzyme targeting genes, as well as energy metabolism in stuttering. Future studies assessing variations of these genes in the participants’ genomes may lead to increased understanding of the biological mechanisms of the observed spatial relationship between gene expression and gray matter volume.

Gray Matter Structure Is Associated with Reading Skill in Typically Developing Young Readers.

Research using functional and structural magnetic resonance imaging has identified areas of reduced brain activation and gray matter volume in children and adults with reading disability, but associations between cortical structure and individual differences in reading in typically developing children remain underexplored. Furthermore, the majority of research linking gray matter structure to reading ability quantifies gray matter in terms of volume, and cannot specify unique contributions of cortical surface area and thickness to these relationships. Here, we applied a continuous analytic approach to investigate associations between distinct surface-based properties of cortical structure and individual differences in reading-related skills in a sample of typically developing young children. Correlations between cortical structure and reading-related skills were conducted using a surface-based vertex-wise approach. Cortical thickness in the left superior temporal cortex was positively correlated with word and pseudoword reading performance. The observed positive correlation between cortical thickness in the left superior temporal cortex and reading may have implications for the patterns of brain activation that support reading.

Associations of Objectively-Assessed Physical Activity and Sedentary Time with Hippocampal Gray Matter Volume in Children with Overweight/Obesity.

This study investigated physical activity (PA) and sedentary time (SED) in relation to hippocampal gray matter volume (GMV) in pediatric overweight/obesity. Ninety-three children (10 ± 1 year) were classified as overweight, obesity type I, or type II–III. PA was assessed with non-dominant wrist accelerometers. GMV was acquired by magnetic resonance imaging (MRI). Neither PA nor SED associated with GMV in the hippocampus in the whole sample (p > 0.05). However, we found some evidence of moderation by weight status (p < 0.150). Moderate-to-vigorous PA (MVPA) positively associated with GMV in the right hippocampus in obesity type I (B = 5.62, p = 0.017), which remained when considering SED, light PA, and sleep using compositional data (γ = 375.3, p = 0.04). Compositional models also depicted a negative association of SED relative to the remaining behaviors with GMV in the right hippocampus in overweight (γ = −1838.4, p = 0.038). Reallocating 20 min/day of SED to MVPA was associated with 100 mm3 GMV in the right hippocampus in obesity type I. Multivariate pattern analysis showed a negative-to-positive association pattern between PA of increasing intensity and GMV in the right hippocampus in obesity type II–III. Our findings support that reducing SED and increasing MVPA are associated with greater GMV in the right hippocampus in pediatric overweight/obesity. Further studies should corroborate our findings.

P.764 The role of cortical geometry and deformation, in antipsychotic treatment optimization. From poroelasticity and information theory to clinical practice

Early-life stressors can adversely affect the developing brain. While hierarchical modeling has established the existence of a general factor of psychopathology, no studies have modeled a general factor of environmental stress and related this factor to brain development. Using a large sample of children from the ABCD (Adolescent Brain Cognitive Development) Study, the current study aimed to identify general and specific factors of environmental stress and test their associations with brain structure and psychopathology.In a sample of 11,878 children, bifactor modeling and higher-order (second-order) modeling identified general and specific factors of environmental stress: family dynamics, interpersonal support, neighborhood socioeconomic status deprivation, and urbanicity. Structural equation modeling was performed to examine associations between these factors and regional gray matter volume (GMV) and cortical thickness as well as general and specific factors of psychopathology.The general environmental stress factor was associated with globally smaller cortical and subcortical GMV as well as thinner cortices across widespread regions. Family dynamics and neighborhood socioeconomic status deprivation were associated with smaller GMV in focal regions. Urbanicity was associated with larger cortical and subcortical GMV and thicker cortices in frontotemporal regions. The environmental factors were associated with psychopathology in the expected directions. The general factors of environmental stress and psychopathology were both predictors of smaller GMV in children, while remaining distinct from each other.This study reveals a unifying model of environmental influences that illustrates the inherent organization of environmental stressors and their relationship to brain structure and psychopathology.

Weight loss, behavioral change, and structural neuroplasticity in children with obesity through a multidisciplinary treatment program.

This study evaluated the effect of a multidisciplinary treatment program for children with obesity (OB) on motor competence, executive functioning (EF), and brain structure. Nineteen children with OB (7-11 years), who attended a multidisciplinary treatment program consisting of diet restriction, cognitive behavioral therapy, and physical activity, were compared with an age-matched control group of 24 children with a healthy weight (HW), who did not follow any treatment. For both groups, anthropometric measurements and tests of motor competence and EF were administered twice, with 5 months between pretest and posttest. Additionally, children's brain structure was assessed by performing a magnetic resonance imaging (MRI) scan at the pretest and posttest, which included a T1 anatomical scan, diffusion MRI scan, and magnetization transfer imaging scan. Compared to HW controls, children with OB lost a considerable amount of their body mass (p ≤ .001) and significantly improved their balance skills (p ≤ .001), while no transfer effects of the program were observed for EF. Furthermore, the program resulted in a significant increase in total (p ≤ .001) and cerebellar (p ≤ .001) gray matter volume in children with OB, while no change was observed in the HW controls. Finally, only weak to moderate (nonsignificant) correlations could be observed between structural brain alterations, weight-related changes, and behavioral improvements. Altogether, this is the first longitudinal study showing behavioral and structural brain alterations in response to a multidisciplinary weight loss program for children with OB. Our findings support the need for multidimensional intervention (and prevention) measures for children with OB to deal with this multifactorial health problem.

Twins methods quantitatively explore the genetic impact on children and adolescents brain gray matter volume

The gray matter volumes of 58 pairs of twins ranging in age from 12 to 18 were measured by MRI to explore the genetic and environmental impacts on gray matter volume in twin children and adolescents. By means of A/C/E structural equation modeling, it was found that the gray matter volume in children and adolescents was jointly affected by genetic (A: 0.89) and environmental factors while genetic factors play a greater role. The gray matter volume in frontal lobe, parietal lobe, occipital lobe and lateral temporal lobe was mainly affected by genetics (A: 0.7–0.89), where as the gray matter volume in medial temporal lobe and cingulate cortex was affected by both genetics and environment.

Parental Praise Correlates with Posterior Insular Cortex Gray Matter Volume in Children and Adolescents.

A positive parenting style affects psychological and cognitive development in children. Neuroimaging studies revealed that a positive parenting style influenced brain structure in children. Parental praise is a concrete behavior observed in positive parenting. Although previous psychological studies revealed a positive effect of parental praise on children, little is known about the relationship between parental praise and brain structure in children. Thus, the purpose of the present study was to determine whether there was a correlation between the parental attitude towards praising their child and gray matter volume in the children (116 boys and 109 girls; mean age, 10.6 years old). We examined the correlation between regional gray matter volume and parental praise using voxel-based morphometry (VBM) following magnetic resonance imaging (MRI). In addition, to confirm the positive effects of parental praise, we analyzed the correlation between the frequency of parental praise and personality traits in children. We showed that the parental attitude towards praising their child was significantly and positively correlated with the gray matter volume of the left posterior insular cortex in children. Moreover, we found a significant positive correlation between parental attitude towards praising their child and the personality traits of conscientiousness and openness to experience in the children. Prior studies said that gray matter volume in the posterior insula was correlated with empathy, and the functional connectivity between this area and the amygdala was associated with emotional regulation. Furthermore, the posterior insula relates to auditory function, and therefore, was likely involved in the processing of parental praise. Considering the possibility of experience-dependent plasticity, frequent parental praise would lead to increased posterior insular gray matter volume in children. Our study is the first to elucidate the relationship between a specific positive parenting behavior and brain structure in children.

Self-reported functional impairment in individuals at clinical high-risk for psychosis

us to examine developmental trajectories that may be associated with psychopathology in these children at risk. The current study will investigate cortical abnormalities by measuring gray matter volume in children and adolescences at lowand high-risk of developing bipolar disorder. Methods: To date, nineteen partially-affected high-risk (HR) offspring (average age = 13.73 (2.81) years, 8 females), and 11 ageand sex-matched healthy controls (HC) (average age = 13.18 (2.74) years, 4 females) have been recruited for this study. Offspring were not excluded if they were diagnosed with depression, attention, behavioural or anxiety-related disorders. Highresolution magnetic resonance structural brain images were taken using a General Electric 3 Tesla scanner. Structural brain scans were analyzed using the CIVET pipeline in CBRAIN to extract measures of cortical thickness. Results: Preliminary whole-brain vertex-wise analyses suggest a significant difference in cortical thickness between HR and HC offspring. HR children had significantly thinner gray matter volumes in the left middle temporal gyrus, Broadmann area 21 (t = 3.98 and t = 3.92), the left superior frontal gyrus, Broadmann area 6 (t = 3.72) and the left parahippocampal gyrus, Broadmann area 27 (t = 3.57) compared to HC offspring. Conclusions: Our results suggest that cortical differences exist between HC children and symptomatic HR bipolar offspring. Specifically, we detected decreased cortical thickness in frontal and temporal areas of children at high risk of developing bipolar disorder.

The alteration of gray matter volume in children with mental retardation: the differences between the patients presented with operation deficit predominantly and those presented with language deficit mainly

Objective To detect the differences of grey matter volume between the patients with mental retardation (MR) presented clinically as operation deficit (OD) or as language deficit (LD) and the children with typical normal development using optimal VBM.The developmental connections between brain gray matter and language or operation skills were examined.Methods Magnetic resonance imaging was obtained from 9 children with mental retardation presented as OD predominantly and 11 children with mental retardation presented as LD mainly,as well as the age-matched control group (11 and 14 normal children,respectively) on a 1.5 T scanner.Voxel-based morphometry analysis with an optimization of spatial segmentation and normalization procedures was applied to compare the volume of grey matter between the two groups (OD VS.control; LD VS.control).Statistically,the total and local gray matter volumes were compared between the two groups with t test.Results The total gray matter volume of OD group was [(1.030 ± 0.078) × 106 mm3].Compared to that of controls [(0.984 ± 0.058) × 106 mm3],it was increased significantly (t =-2.6,P ＜ 0.05).And the gray matter volume in the posterior cingulated gyrus,left superior prefrontal gyrus,left cuneus,left middle prefrontal gyrus and the body of left caudate nucleus showed significantly increased.Meanwhile,the total gray matter volume of the MR children presented as LD [(1.002 ± 0.068) × 106 mm3] showed significantly increased(t =-3.0,P ＜ 0.05) compared with that of control group [(0.957 ±0.057) × 106 mm3].The gray matter volume in bilateral thalami,the left inferior temporal gyrus,the left inferior frontal gyrus,and the left cerebellum of the LD group was more than that of normal children.Conclusion As revealed by VBM,there are differences in alterations of gray matter volume between MR children presented with OD and with LD relative to control. Key words: Child ; Mental retardation ; Magnetic resonance imaging; Brain

Investigation of thealteration of gray matter volume in children with mental retardation with the optimalvoxel-based morphometry

：Objective To detectbrain structural difference between children with unexplained mental retardation andchildren with typically normal development. Methods The high-resolution magnetic MRimaging were obtained from 21 children with unexplained mental retardation and 30age-matched control children without intellectual disabilities. Voxel-based morphometryanalysis with an optimization of spatial segmentation and normalization procedures wereapplied to compare differences of gray matter volume between the two groups. The total andregional gray matter volume were compared between the two groups with independent t test.Meanwhile, correlation was conducted to analyze the relationship between the total graymatter volume and intelligence quotient (IQ) with partial correlation test. Results Thetotal gray matter volume was significantly increased in the mental retardation children[(1. 012 ±0. 079) × 106 mm3]in relative to the controls [(0. 956 ± 0. 059) × 106 mm3,t = - 2. 80, P ＜ 0. 05]. Compared tocontrols,children with unexplained mental retardation showed significantly increased graymatter volume in different regions, including the bilateral thalami, the bilateralsuperior frontal gyri, the bilateral gyri rectus, the bilateral temporal poles, the rightinferior frontal gyrus, right parahippocampal gyrus and the right cerebellum. Nocorrelation was detected between the total gray matter volume and IQ in children withmental retardation (r = 0. 078 ,P ＞ 0. 05). Conclusions VBM would detect the gray matterabnormalities that were not founded in routine MR scanning. The increase of gray mattervolume in the frontal-thalamus network might indicate the delayed maturation of the braindevelopment. This might be one of the causations of mental retardation in children. Key words: Mental retardation; Magnetic resonance imaging; Brain; Child