Cortical Thickness In Children Research Articles

Brain volumes and cortical thickness and associations with cognition in children born extremely preterm.

Children born extremely preterm (EPT) have altered brain volumes and cortical thickness and lower cognition than children born at term. Associations between these have remained largely unexplored, due to the lack of studies focusing on children born EPT. Children underwent brain magnetic resonance imaging (MRI) at term and/or 10 years and cognitive assessments at 12 years. The study comprised of 42 children born EPT and 29 term-born controls with cognitive data and MRI data at 10 years, 25 children born EPT had MRI data at term age and 20 had longitudinal MRI data. Cognition was positively associated with brain volumes at 10 years, but negatively associated with cortical thickness at 10 years. Most associations between term age brain volumes and cognitive outcomes were non-significant for children born EPT. Growth from term to 10 years in children born EPT was not associated with cognition. Insular volume was positively associated with cognition in children born EPT. Imaging assessments at 10 years had similar associations to cognition in children born EPT and term-born controls. Insular volume could be a biomarker for cognitive outcome. Associations between brain volumetric growth and cognition require further investigation. This study investigated brain volumes, volumetric growth, and cortical thickness in children born extremely preterm, who have rarely been studied exclusively, and compared the data with term-born controls. In both groups, brain volumes at 10 years were positively associated with cognitive outcome at 12 years, but cortical thickness at 10 years was negatively associated with cognitive outcome at 12 years. Volumetric growth from term age to 10 years was not associated with cognitive outcome in the subset of children born extremely preterm with longitudinal data. Insular volume may be a potential biomarker for cognitive outcome in children born extremely preterm.

Language performance and brain volumes, asymmetry, and cortical thickness in children born extremely preterm

BackgroundChildren born preterm are more prone to have language difficulties. Few studies focus on children born extremely preterm (EPT) and the structural differences in language-related regions between these children and children born at term.MethodsOur study used T1-weighted magnetic resonance imaging (MRI) scans to calculate the brain volumetry, brain asymmetry, and cortical thickness of language-related regions in 50 children born EPT and 37 term-born controls at 10 years of age. The language abilities of 41 of the children born EPT and 29 term-born controls were then assessed at 12 years of age, using the Wechsler Intelligence Scale for Children, Fifth Edition and the Clinical Evaluations of Language Fundamentals, Fourth Edition. The differences between MRI parameters and their associations with language outcomes were compared in the two groups.ResultsBrain volume and cortical thickness of language-related regions were reduced in children born EPT, but volumetric asymmetry was not different between children born EPT and at term. In children born EPT the brain volume was related to language outcomes, prior to adjustments for full-scale IQ.ConclusionsThese findings expand our understanding of the structural correlates underlying impaired language performance in children born with EPT.ImpactThe article expands understanding of the structure-function relationship between magnetic resonance imaging measurements of language-related regions and language outcomes for children born extremely preterm beyond infancy.Most literature to date has focused on very preterm children, but the focus in this paper is on extreme prematurity and language outcomes.While the brain volume and cortical thickness of language-related regions were reduced in children born EPT only the volume, prior to adjustment for full-scale IQ, was associated with language outcomes.We found no differences in volumetric asymmetry between children born EPT and at term.

Regional Cortical Thickness Correlates of Intellectual Abilities Differ in Children With Traumatic Brain Injury Versus Those With Orthopedic Injury in the Chronic Post-Injury Phase.

A decline in intellectual functioning (intelligence quotient [IQ]) is often observed following more severe forms of traumatic brain injury (TBI) and is a useful index for long-term outcome. Identifying brain correlates of IQ can serve to inform developmental trajectories of behavior in this population. Using magnetic resonance imaging (MRI), we examined the relationship between intellectual abilities and patterns of cortical thickness in children with a history of TBI or with orthopedic injury (OI) in the chronic phase of injury recovery. Participants were 47 children with OI and 58 children with TBI, with TBI severity ranging from complicated-mild to severe. Ages ranged from 8 to 14 years old, with an average age of 10.47 years, and an injury-to-test range of ∼1-5 years. The groups did not differ in age or sex. The intellectual ability estimate (full-scale [FS]IQ-2) was derived from a two-form (Vocabulary and Matrix Reasoning subtests) Wechsler Abbreviated Scale of Intelligence (WASI). MRI data were processed using the FreeSurfer toolkit and harmonized across data collection sites using neuroComBat procedures, while holding demographic features (i.e., sex, socioeconomic status [SES]), TBI status, and FSIQ-2 constant. Separate general linear models per group (TBI and OI) and a single interaction model with all participants were conducted with all significant results withstanding correction for multiple comparisons via permutation testing. Intellectual ability was higher (p < 0.001) in the OI group (FSIQ-2 = 110.81) than in the TBI group (FSIQ-2 = 99.81). In children with OI, bi-hemispheric regions, including the right pre-central gyrus and precuneus and bilateral inferior temporal and left occipital areas were related to IQ, such that higher IQ was associated with thicker cortex in these regions. In contrast, only cortical thickness in the right pre-central gyrus and bilateral cuneus positively related to IQ in children with TBI. Significant interaction effects were found in the bilateral temporal, parietal, and occipital lobes and left frontal regions, indicating that the relationship between IQ and cortical thickness differed between groups in these regions. Changes in cortical associations with IQ after TBI may reflect direct injury effects and/or adaptation in cortical structure and intellectual functioning, particularly in the bilateral posterior parietal and inferior temporal regions. This suggests that the substrates of intellectual ability are particularly susceptible to acquired injury in the integrative association cortex. Longitudinal work is needed to account for normal developmental changes and to investigate how cortical thickness and intellectual functioning and their association change over time following TBI. Improved understanding of how TBI-related cortical thickness alterations relate to cognitive outcome could lead to improved predictions of outcome following brain injury.

Bilingualism and creativity across development: Evidence from divergent thinking and convergent thinking.

Numerous studies have demonstrated the benefits of creativity from bilingualism. Divergent thinking and convergent thinking are considered the two most important components of creativity. Various (although not all) studies have concluded that bilingual children outperform monolingual children in divergent thinking, however, no study on children or adolescents so far has explored the relation between bilingualism and convergent thinking, or the brain structural basis of interaction between bilingualism and creativity. This study aimed to explore the impact of bilingualism on both convergent and divergent thinking in children and adolescents based on neuropsychological assessments, and the possible structural basis of the effect of bilingualism on creativity by a whole-brain analysis of regional gray matter volume (rGMV) and cortical thickness in children and adolescents. 92 healthy children and adolescents of age 4-18 were recruited from public or private schools in the French-speaking side of Switzerland. Demographic data of the participants were collected, including gender, age, pedagogy, usage of language, and parents' socioeconomic status. Most of the participants underwent the neuropsychological assessments of divergent thinking, convergent thinking, and fluid intelligence. Structural image data of 75 participants were analyzed. Both voxel-based morphometry (VBM) and surface-based morphometry (SBM) were processed, to perform the analyses of rGMV and cortical thickness respectively. The outcomes indicated that convergent thinking, but not divergent thinking benefits from bilingualism in children and adolescents. However, this bilingual advantage appears to weaken across development. Unexpectedly, no significant correlation between morphometry and bilingualism was found. Neither divergent thinking scores nor convergent thinking scores showed any significant correlation with rGMV. However, the whole brain SBM showed that the cortical thickness in the right supplementary motor area (SMA) was negatively correlated with convergent thinking scores, which suggested that the children and adolescents with higher convergent thinking abilities may have thinner, more mature, and more activated cortex in the right SMA. Bilingualism and cortical thinness in the right SMA might facilitate convergent thinking independently, by enhancing this selective ability.

Alterations in Cortical Thickness in Children with Congenital Strabismus and Dissociated Vertical Deviation

Introduction: Little is known about the morphometric changes that occur in the cerebral cortex of children with congenital strabismus and Dissociated Vertical Deviation (DVD). Mathematical morphology provides the opportunity to discover alterations in cortical thickness. Objective: Identify and measure differences in cortical thickness in children with congenital strabismus and DVD. Materials and Methods: Twenty-two MRI brain studies were conducted, each comprising 120 sagittal slices of 1 mm. A cohort of 11 healthy children formed the control group, and a cohort of 11 children with congenital strabismus and Dissociated Vertical Deviation, both in Dissociated Esotropia and Dissociated Exotropia formed the case group. Differences in cortical thickness between both groups were compared and identified using the FreeSurfer suite. Subsequently, areas of interest were analyzed using the ImageJ program to determine density, area, size, and pixel quantity in these regions. Study results are presented through tables and figures. Results: Twelve inflated brain projections were obtained from 2640 MRI images. Thickness differences between both groups exhibited three areas with significant morphometric changes: the Left Angular Gyrus, Left Supramarginal Gyrus, and Right Pars Opercularis. Discussion: Children with congenital strabismus and DVD showed changes in cortical thickness that could be identified and measured through Voxel-Based Morphometry (VBM). It is plausible to consider that these changes are related to suppression, aiming to avoid diplopia.

Socioeconomic disparities in sleep duration are associated with cortical thickness in children.

Disrupted sleep has been consistently linked with lower academic achievement and worse mental health in children. Less is understood about sleep as a potential factor underlying socioeconomic differences in brain morphometry in children. The goals of this study were to investigate the associations among socioeconomic factors, sleep duration, and brain morphometry in children, and to examine the roles of the sleep environment and family routines in these associations. Participants were 5- to 9-year-old children from socioeconomically diverse families (N=94; 61% female). Parents reported on children's weekday and weekend sleep durations, sleep environment, and family routines. High-resolution, T1-weighted structural magnetic resonance imaging (MRI) data were acquired. Analyses focused on cortical thickness, cortical surface area, and amygdala and hippocampal volume. Results indicated that lower family income-to-needs ratio and parental education were significantly associated with shorter weekday sleep duration in children. Shorter weekday sleep duration was significantly associated with reduced thickness in the left middle temporal, right postcentral, and right superior frontal cortices and smaller basolateral but not centromedial amygdala volume. Family routines significantly mediated the associations of family income-to-needs ratio and parental education with weekday sleep duration in children. These results contribute to our understanding of sleep factors as proximal mechanisms through which socioeconomic context may alter neural development during childhood.

Relationships between physical activity, healthy eating and cortical thickness in children and young adults.

Prior neuroimaging studies have shown associations between healthy lifestyle factors and cortical thickness; however, results on the direction of this association have been inconsistent. While the majority of studies were performed in older adults within specific weight status categories, little has been reported in younger populations with a range of adiposity, including groups with healthy-weight, overweight, and obesity. Here we investigated relationships between indices of physical activity (PA) and healthy eating with cortical thickness in children and youth/young adults and examined whether these relationships differed by weight status and age groups. Study participants included 119 youth/young adults and 159 children. We hypothesized that greater levels of PA and/or healthy eating index (HEI) composite scores would be positively associated with cortical thickness, and that this association would differ in overweight or obese groups versus normal weight groups, as well as youth/young adults vs. child cohorts. Overall PA (minutes/day) was assessed using 24-hour PA recalls. HEI was calculated to assess diet quality. A structural MRI was performed, and FreeSurfer 6.0 was used to assess cortical thickness in 68 regions of interest (ROI). Mixed effects modeling was performed to investigate associations of PA or HEI with cortical thickness. FDR corrections were applied for multiple ROIs. PA was positively associated with cortical thickness in the caudal middle frontal cortex (FDR adjusted p = 0.042) and cuneus cortex (FDR adjusted p = 0.017) after controlling for sex, age group, and weight status. When stratified by age, in youth/young adults, higher time spent in PA was associated with greater cortical thickness in the frontal, temporal, parietal and occipital cortex, after adjusting for sex and weight group (FDR adjusted ps < 0.05). No significant associations between PA and cortical thickness were observed in children. No significant associations between PA and cortical thickness were observed when stratified by weight group. No significant associations between HEI and cortical thickness were observed. These results indicate that higher time spent in PA is associated with greater cortical thickness, a relationship that appears to be stronger during youth/young adulthood and may be related to more favorable brain health outcomes.

Febrile seizures reduce hippocampal subfield volumes but not cortical thickness in children with focal onset seizures

ObjectivesWhether febrile seizures (FS) produce long-term injury to the hippocampus or other brain structures is a critical question concerning focal onset seizures in children. Our aims are to evaluate the effect of FS on subfields of the hippocampus, thalamic nuclei, amygdala, cortical thickness, and surface area quantitatively in children with FS who later developed focal seizures and to identify biomarkers based on MRI structures. MethodsChildren who had focal onset seizures with or without previous FS and normal 3-T MRI findings were included retrospectively. The MRI was performed within 2 years after the onset of focal seizures. Age-matched controls were also recruited. Hippocampal subfields and thalamic nuclei, amygdala volumes, cortical thickness, and cortical surface area in individual cortical regions were segmented by FreeSurfer version 7.1.1. Volumetric and morphometric data among children who had focal seizures with or without previous FS, as well as controls, were compared and correlated with clinical parameters. ResultsChildren with a history of FS who had focal seizures exhibited smaller right cornu ammonis (CA) 1 and right molecular cell layer of the hippocampus, compared to those without FS. A larger left hippocampal fissure was also found in FS with focal seizures compared to age-matched controls. There were no statistically significant differences in each nucleus of the thalamus, amygdala, cortical thickness, and surface area of each cortical region among the three groups. A smaller whole hippocampal volume was found for the right hippocampus in children with FS and focal seizures compared to those without FS. A trend of negative correlation was found between the frequency of FS and the left and right CA1 subfield volume ratios of the hippocampus. ConclusionsWe concluded that multiple episodes of FS may be associated with a trivial difference in volume reduction in the CA1 and molecular layer of the right hippocampus and an enlarged hippocampal fissure of the left hippocampus, but not with individual cortical thicknesses, surface area, thalamic nuclei, or amygdala in children with focal onset seizures.The hippocampal subfield CA1 and molecular layer of the right hippocampus may be more vulnerable than the cortices in children with focal seizures who experienced multiple FS episodes. This study highlights the minimal differences in brain volumes among children with recent onset focal seizures with or without FS history and controls, suggesting that the brain injurious aspects of the FS and recent onset focal seizures may have been previously overstated. This suggests that physicians can be reassuring about brain injury associated with these seizure types when discussing outcomes with parents and patients.

Brain network modularity predicts changes in cortical thickness in children involved in a physical activity intervention.

Individual differences in brain network modularity at baseline can predict improvements in cognitive performance after cognitive and physical interventions. This study is the first to explore whether brain network modularity predicts changes in cortical brain structure in 8- to 9-year-old children involved in an after-school physical activity intervention (N=62), relative to children randomized to a wait-list control group (N=53). For children involved in the physical activity intervention, brain network modularity at baseline predicted greater decreases in cortical thickness in the anterior frontal cortex and parahippocampus. Further, for children involved in the physical activity intervention, greater decrease in cortical thickness was associated with improvements in cognitive efficiency. The relationships among baseline modularity, changes in cortical thickness, and changes in cognitive performance were not present in the wait-list control group. Our exploratory study has promising implications for the understanding of brain network modularity as a biomarker of intervention-related improvements with physical activity.

Association of Latent Trauma With Distinctive Patterns of Cortical Thickness in Children

The developing brain is marked by high plasticity which can lead to vulnerability to early life stressors, such as trauma. Trauma has been shown to affect brain structure and to increase the risk of developing psychopathology later in life. However, previous studies on the relationship between trauma and brain structure are limited by small sample size, case-control designs, and heterogeneous age groups. The present study aimed to investigate how trauma is associated with cortical thickness and gray matter volume (GMV) in the early developmental stage by leveraging a large sample of 9 to 10-year-old children (N=9,270) from the Adolescent Brain and Cognitive Development Study (ABCD Study).

Regional Cortical Thickness in Children and Adolescents with Obesity

Regional Cortical Thickness in Children and Adolescents with Obesity

儿童青少年皮层厚度的发展：基于核磁影像的研究

儿童青少年皮层厚度的发展：基于核磁影像的研究

Parental hostility predicts reduced cortical thickness in males.

Although impacts of negative parenting on children's brain development are well-documented, little is known about how these associations may differ for males and females in childhood. We examined interactions between child sex and early and concurrent parental hostility on children's cortical thickness and surface area. Participants included 63 children (50.8% female) assessed during early childhood (Wave 1: M age=4.23years, SD=0.84) and again three years later (Wave 2: M age=7.19years, SD=0.89) using an observational parent-child interaction task. At Wave 2, children completed a structural MRI scan. Analyses focused on regions of interest. After correcting for multiple comparisons, Wave 1 parental hostility predicted males' reduced thickness in middle frontal and fusiform cortices, and Wave 2 parental hostility was concurrently associated with males' reduced thickness in the middle frontal cortex. Interactions between sex and parenting on children's surface area did not survive corrections for multiple comparisons. Our findings provide support for a male-specific neural vulnerability of hostile parenting across development. Results have important implications for uncovering neural pathways to sex-differences in psychopathology, learning, and cognitive disabilities.

Methylphenidate Effects on Cortical Thickness in Children and Adults with Attention-Deficit/Hyperactivity Disorder: A Randomized Clinical Trial.

Although methylphenidate is frequently used to treat children with attention-deficit/hyperactivity disorder, it is currently unknown how methylphenidate affects brain development. In a randomized controlled trial, we investigated whether the cortical effects of methylphenidate are modulated by age. Between June 1, 2011, and June 15, 2015, we conducted a randomized, double-blind, placebo-controlled trial (Effects of Psychotropic Drugs on Developing Brain-Methylphenidate) in 99 males with attention-deficit/hyperactivity disorder (according to Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, criteria) from referral centers in the greater Amsterdam area in the Netherlands. The trial was registered on March 24, 2011 (identifier NL34509.000.10) and subsequently at the Netherlands National Trial Register (identifier NTR3103). Participants (first enrolled October 13, 2011) were 10-12 years or 23-40 years of age and randomized to treatment with either methylphenidate or a placebo for 16 weeks. Our main outcome was a change in cortical thickness in predefined ROIs as measured by MR imaging pre- and posttreatment. We observed a time × medication × age interaction (F[1,88.825] = 4.316, P < .05) for the right medial cortex ROI, where methylphenidate treatment yielded less cortical thinning in children, but not in adults or the placebo groups. Our finding that the effects of methylphenidate on right medial cortical thickness differ between children and adults infers that the drug affects gray matter development in this brain region. This warrants replication in larger groups with longer follow-up to determine whether this effect can also be observed in other cortical brain regions and whether it may have long-term consequences.

TEMPORARY REMOVAL: Changes of regional cortical thickness in children with post-traumatic stress disorder—A magnetic resonance imaging study

Abstract Neuroimaging studies suggest altered gray matter in adults with post-traumatic stress disorder (PTSD). But the impact of PTSD on brain structure in children is rarely known. The study aimed to examine the alterations of gray matter thickness in children with PTSD. Fifty-one children (26 with and 25 without PTSD) were imaged by 3.0 T magnetic resonance imaging (MRI). This research uses FreeSurfer software for exploratory analysis. Children with PTSD showed thinner cortical thickness in the bilateral frontal, parietal, and temporal gyrus, and thicker thickness in the left middle temporal gyrus, as well as the right insula, compared with those without PTSD. The cortical thickness of the left middle temporal gyrus is negatively correlated with age (Pearson's correlation, r = 0.558, P = 0.003). The cortical thickness of the right insula of female children with PTSD is different from that of female non-PTSD survivors (P = 0.027). These results suggest that stress can have a potential impact on the specific brain regions of a child with PTSD. Changes in cortical thickness may provide some potential information about the age and gender of children with PTSD.

Association of Optic Radiation Integrity with Cortical Thickness in Children with Anisometropic Amblyopia.

Previous studies have indicated regional abnormalities of both gray and white matter in amblyopia. However, alterations of cortical thickness associated with changes in white matter integrity have rarely been reported. In this study, structural magnetic resonance imaging and diffusion tensor imaging (DTI) data were obtained from 15 children with anisometropic amblyopia and 15 age- and gender-matched children with normal sight. Combining DTI and surface-based morphometry, we examined a potential linkage between disrupted white matter integrity and altered cortical thickness. The fractional anisotropy (FA) values in the optic radiations (ORs) of children with anisometropic amblyopia were lower than in controls (P<0.05). The cortical thickness in amblyopic children was lower than controls in the following subregions: lingual cortex, lateral occipitotemporal gyrus, cuneus, occipital lobe, inferior parietal lobe, and temporal lobe (P<0.05, corrected), but was higher in the calcarine gyrus (P<0.05, corrected). Node-by-node correlation analysis of changes in cortical thickness revealed a significant association between a lower FA value in the OR and diminished cortical thickness in the following subregions: medial lingual cortex, lateral occipitotemporal gyrus, lateral, superior, and medial occipital cortex, and lunate cortex. We also found a relationship between changes of cortical thickness and white matter OR integrity in amblyopia. These findings indicate that developmental changes occur simultaneously in the OR and visual cortex in amblyopia, and provide key information on complex damage of brain networks in anisometropic amblyopia. Our results also support the hypothesis that the pathogenesis of anisometropic amblyopia is neurodevelopmental.

Does a Mother's Depression Affect Her Baby's Brain?

To explore depression's teratogenic effects on prenatal brain development, researchers studied 52 pregnant women and their children. Mothers' depression-screening scores were obtained during each trimester of pregnancy and at 3 months postpartum; magnetic resonance imaging was used to measure children's cortical thickness and white-matter connectivity at ages 2.6 to 5.1 years. No diagnostic interviews were conducted. Depending on the screening-score cutoff, a diagnosis of major depression was suggested in 4% of women …

Prenatal Cannabis and Tobacco Exposure in Relation to Brain Morphology: A Prospective Neuroimaging Study in Young Children

BackgroundCannabis use during pregnancy has been associated with negative behavioral outcomes and psychopathology in offspring. However, there has been little research evaluating alterations in brain structure as a result of maternal cannabis use. In this prospective study, we investigated the association between prenatal cannabis exposure and brain morphology in young children. MethodsWe matched 96 children prenatally exposed to tobacco only (without cannabis) with 113 unexposed control subjects on the basis of age and gender and subsequently selected 54 children exposed to prenatal cannabis (mostly combined with tobacco exposure). These children (aged 6 to 8 years) were part of a population-based study in the Netherlands, the Generation R Study, and were followed from pregnancy onward. We assessed brain volumetric measures and cortical thickness in magnetic resonance imaging scans using FreeSurfer. We performed vertexwise analyses in FreeSurfer and linear regression analyses adjusting for relevant covariates using Statistical Package for the Social Sciences. ResultsPrenatal cannabis exposure was not associated with global brain volumes, such as total brain volume, gray matter volume, or white matter volume. However, prenatal cannabis exposure was associated with differences in cortical thickness: compared with nonexposed control subjects, cannabis-exposed children had thicker frontal cortices. Prenatal tobacco exposure compared with nonexposed control subjects was associated with cortical thinning, primarily in the superior frontal and superior parietal cortices. ConclusionsOur findings suggest an association between prenatal cannabis exposure and cortical thickness in children. Further research is needed to explore the causal nature of this association.

Morphological abnormalities in prefrontal surface area and thalamic volume in attention deficit/hyperactivity disorder

Although previous morphological studies have demonstrated abnormalities in prefrontal cortical thickness in children with attention deficit/hyperactivity disorder (ADHD), studies investigating cortical surface area are lacking. As the development of cortical surface is closely linked to the establishment of thalam-ocortical connections, any abnormalities in the structure of the thalamus are likely to relate to altered cortical surface area. Using a clinically well-defined sample of children with ADHD (n=25, 1 female) and typically developing controls (n=24, 1 female), we studied surface area across the cortex to determine whether children with ADHD had reduced thalamic volume that related to prefrontal cortical surface area. Relative to controls, children with ADHD had a significant reduction in thalamic volume and dorsolateral prefrontal cortical area in both hemispheres. Furthermore, children with ADHD with smaller thalamic volumes were found to have greater reductions in surface area, a pattern not evident in the control children. Our results are further evidence of reduced lateral prefrontal cortical area in ADHD. Moreover, for the first time, we have also shown a direct association between thalamic anatomy and frontal anatomy in ADHD, suggesting the pathophysiological process that alters surface area maturation is likely to be linked to the development of the thalamus.

Associations between serotonin transporter gene (SLC6A4) methylation and clinical characteristics and cortical thickness in children with ADHD.

Attention deficit hyperactivity disorder (ADHD) is a common, highly heritable psychiatric disorder. Additionally, environmental factors such as perinatal stress and early adversities contribute to the occurrence and severity of ADHD. Recently, DNA methylation has emerged as a mechanism that potentially mediates gene-environmental interaction effects in the aetiology and phenomenology of psychiatric disorders. Here, we investigated whether serotonin transporter gene (SLC6A4) methylation patterns were associated with clinical characteristics and regional cortical thickness in children with ADHD. In 102 children with ADHD (age 6-15 years), the methylation status of the SLC6A4 promoter was measured. Brain magnetic resonance imaging was obtained and ADHD symptoms were evaluated. A higher methylation status of the SLC6A4 promoter was significantly associated with worse clinical presentations (more hyperactive-impulsive symptoms and more commission errors). Additionally, a negative correlation was observed between SLC6A4 methylation levels and cortical thickness values in the right occipito-temporal regions. Our results suggest that the SLC6A4 methylation status may be associated with certain symptoms of ADHD, such as behavioural disinhibition, and related brain changes. Future studies that use a larger sample size and a control group are required to corroborate these results.