Biology subjects

de Bruijn, S.

Publications and source records attributed to de Bruijn, S..

3 recordsLinked to original sources

bioRxiv2021

Longitudinal changes of ADHD symptoms in association with white matter microstructure: a tract-specific fixel-based analysis

BackgroundVariation in the longitudinal course of childhood attention deficit/hyperactivity disorder (ADHD) coincides with neurodevelopmental maturation of brain structure and function. Prior work has attempted to determine how alterations in white matter (WM) relate to changes in symptom severity, but much of that work has been done in smaller cross-sectional samples using voxel-based analyses. Using standard diffusion-weighted imaging (DWI) methods, we previously showed WM alterations were associated with ADHD symptom remission over time in a longitudinal sample of probands, siblings, and unaffected individuals. Here, we extend this work by further assessing the nature of these changes in WM microstructure by including an additional follow-up measurement (aged 18 - 34 years), and using the more physiologically informative fixel-based analysis (FBA). MethodsData were obtained from 139 participants over 3 clinical and 2 follow-up DWI waves, and analyzed using FBA in regions-of-interest based on prior findings. We replicated previously reported significant models and extended them by adding another time-point, testing whether changes in combined ADHD and hyperactivity-impulsivity (HI) continuous symptom scores are associated with fixel metrics at follow-up. ResultsClinical improvement in HI symptoms over time was associated with more fiber density at follow-up in the left corticospinal tract (lCST) (tmax=1.092, standardized effect[SE]=0.044, pFWE=0.016). Improvement in combined ADHD symptoms over time was associated with more fiber cross-section at follow-up in the lCST (tmax=3.775, SE=0.051, pFWE=0.019). Conclusions: Aberrant white matter development involves both lCST micro- and macrostructural alterations, and its path may be moderated by preceding symptom trajectory.

neuroscience↗

bioRxiv2018

Reactive/proactive aggression specific cortical and subcortical alterations in children and adolescents with disruptive behavior

ObjectiveMaladaptive aggression, as present in conduct disorder (CD) and, to a lesser extent, oppositional defiant disorder (ODD), has been associated with structural alterations in various brain regions, such as ventromedial prefrontal cortex (vmPFC), anterior cingulate cortex (ACC), amygdala, insula and ventral striatum. Although aggression can be subdivided into reactive and proactive subtypes, no neuroimaging studies have yet investigated if any structural brain alterations are associated with either of the subtypes specifically. Here we investigated this association in predefined regions of interest.\n\nMethodT1-weighted magnetic resonance images were acquired from 158 children and adolescents with aggressive behavior (ODD/CD) and 96 controls in a multi-centre study. Aggression subtypes were assessed by questionnaires. Cortical volume and subcortical volumes and shape were determined using Freesurfer and the FMRIB integrated registration and segmentation tool. Associations between volumes and continuous measures of aggression were established using multilevel linear mixed effects models.\n\nResultsIn cases only proactive aggression was negatively associated with amygdala volume (b=-11.82, p=0.05), while reactive aggression was negatively associated with insula volume (b=-46.41, p=0.01). Classical group comparison showed that children and adolescents with aggressive behavior had smaller volumes than controls in (bilateral) ventral striatum (p=0.003), ACC (p=0.01), and vmPFC (p=0.003) with modest effect sizes.\n\nConclusionsAggression was associated with reduced volume in brain regions involved in decision making. Negative associations were found between reactive aggression and volumes in regions involved in threat responsivity and between proactive aggression and regions linked to empathy. This provides evidence for aggression subtype-specific alterations in brain structure.

neuroscience↗

bioRxiv2017

Phylogenomic Synteny Network Analysis Reveals an Ancient MADS-Box Transcription Factor Tandem Duplication and Lineage-Specific Transpositions

Conserved genomic context (or synteny) provides critical information for comparative evolutionary analysis, such as the inference of ancient polyploidy events, recurrent genomic rearrangements across species and gene ancestry. With the increase of sequenced and assembled plant genomes, we now have the opportunity to use synteny to analyze the dynamics of gene family expansion and contraction across broad phylogenetic groups. Here we present an integrated approach to organize plant kingdom-wide gene synteny networks using k-clique percolation. As an example, we analyzed the gene synteny network of the MADS-box transcription factor family based on fifty-one completed plant genomes. We conclude from two massive gene clusters that one of the two Type II MADS-box gene clades evolved from an ancient tandem gene duplication likely predating the radiation of seed plants, which then expanded by polyploidy events and sub-functionalization. This gene clade now contains key regulators of major phenotypes of angiosperms including flower development. Moreover, we find lineage-specific gene clusters derived from transposition events. For example, lineage-specific clusters in the Brassicales containing genes that are well-known for their function in controlling flower morphology (AP3 and PI). Our phylogenomic synteny network approach can be applied to any group of species to gain new insights into the evolution and dynamics of any set of genes.

genomics↗