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Background: Neuroimaging findings have provided evidence for a relation between variations in brain structures and Attention Deficit/Hyperactivity Disorder (ADHD). However, longitudinal neuroimaging studies are typically confined to children who have already been diagnosed with ADHD. In a population-based study, we aimed to characterize the prospective association between brain structures measured during infancy and executive function and attention deficit/hyperactivity problems assessed at preschool age. Methods: In the Generation R Study, the corpus callosum length, the gangliothalamic ovoid diameter (encompassing the basal ganglia and thalamus), and the ventricular volume were measured in 784 6-week-old children using cranial postnatal ultrasounds. Parents rated executive functioning at 4 years using the Behavior Rating Inventory of Executive Function-Preschool Version in five dimensions: inhibition, shifting, emotional control, working memory, and planning/organizing. Attention Deficit/Hyperactivity Problems were assessed at ages 3 and 5 years using the Child Behavior Checklist. Results: A smaller corpus callosum length during infancy was associated with greater deficits in executive functioning at 4 years. This was accounted for by higher problem scores on inhibition and emotional control. The corpus callosum length during infancy did not predict Attention Deficit/Hyperactivity Problem at 3 and 5 years, when controlling for the confounders. We did not find any relation between gangliothalamic ovoid diameter and executive function or Attention Deficit/Hyperactivity Problem. Conclusions: Variations in brain structures detectible in infants predicted subtle impairments in inhibition and emotional control. However, in this population-based study, we could not demonstrate that early structural brain variations precede symptoms of ADHD. [ABSTRACT FROM AUTHOR]

Background: Previous research highlights the significance of a functional polymorphism located in the promoter region (5-HTTLPR) of the serotonin transporter gene in emotional behaviour. This study examined the effect of the 5-HTTLPR polymorphism on emotion processing in a large number of healthy preschoolers. Methods: The 5-HTTLPR genotype was classified in 605 children as homozygous for the short allele (SS), homozygous for the long allele (LL), or heterozygous (LS). Emotion-processing was assessed using age-appropriate computer tasks where children matched happy, sad, angry, and fearful facial expressions preceded by a shape-matching task to assess basic matching ability. Results: We found that young children could differentiate between emotion categories ( F = 12.1, p < .001). The effect of 5-HTTLPR genotype depended on the emotion category presented ( F = 2.3, p = .031). This effect was explained by the finding that SS children were less accurate at recognising fearful faces than LL or LS children ( F = 5.3, p = .005). We did not find any significant differences as a result of 5-HTTLPR genotype for happy, sad or angry expressions ( p > .05). Conclusions: Results indicate that 5-HTTLPR allele status selectively impacts the processing of fearful but not other facial expressions. This pattern is already apparent in very young typically developing children. Results may signal an early vulnerability for affective problems before disorders emerge. [ABSTRACT FROM AUTHOR]