A Standardized Protocol for Efficient and Reliable Quality Control of Brain Registration in Functional MRI Studies.

Automatic alignment of brain anatomy in a standard space is a key step when processing magnetic resonance imaging for group analyses. Such brain registration is prone to failure, and the results are therefore typically reviewed visually to ensure quality. There is however no standard, validated protocol available to perform this visual quality control (QC).

The Quebec Newborn Twin Study at 21.

This paper is a revised and updated edition of a previous description of the Quebec Newborn Twin Study (QNTS), an ongoing prospective longitudinal follow-up of a birth cohort of twins born between 1995 and 1998 in the greater Montreal area, Québec, Canada. The goal of QNTS is to document individual differences in the cognitive, behavioral, and social-emotional aspects of developmental health across childhood, their early genetic and environmental determinants, as well as their putative role in later social-emotional adjustment, school, health, and occupational outcomes. A total of 662 families of twins were initially assessed when the twins were aged 6 months.

Identifying craniofacial features associated with prenatal exposure to androgens and testing their relationship with brain development.

We used magnetic resonance (MR) images obtained in same-sex and opposite-sex dizygotic twins (n = 119, 8 years of age) to study possible effects of prenatal androgens on craniofacial features. Using a principal component analysis of 19 craniofacial landmarks placed on the MR images, we identified a principal component capturing craniofacial features that distinguished females with a presumed differential exposure to prenatal androgens by virtue of having a male (vs. a female) co-twin (Cohen's d = 0.

A methodological comparison of the Porges algorithm, fast Fourier transform, and autoregressive spectral analysis for the estimation of heart rate variability in 5-month-old infants.

Little empirical evidence exists on the comparability of heart rate variability (HRV) quantification methods commonly used in infants. The aim was to compare three methods of HRV estimation: (1) fast Fourier transform (FFT), (2) autoregressive (AR), and (3) the Porges methods. HRV was estimated in 63 healthy 5-month-old infants.

Genetic and environmental influences on eating behaviors in 2.5- and 9-year-old children: a longitudinal twin study.

Background: Eating behaviors during childhood are related both to children's diet quality and to their weight status. A better understanding of the determinants of eating behavior during childhood is essential for carrying out effective dietary interventions.

Methods: We assessed the contribution of genetic and environmental factors to variations in selected eating behaviors in early and late childhood.

Gene-environment processes linking peer victimization and physical health problems: a longitudinal twin study.

Objective: This study examined whether (a) a genetic disposition for physical health problems increases the risk of peer victimization and (b) peer victimization interacts with genetic vulnerability in explaining physical health problems.

Methods: Participants were 167 monozygotic and 119 dizyogtic twin pairs. Physical symptoms were assessed in early childhood and early adolescence.

Gene-environment contributions to energy and macronutrient intakes in 9-year-old children: results from the Quebec Newborn Twin Study.

Background: Few twin studies have examined nutrition-related phenotypes among children, and none has investigated energy and macronutrient intakes.

Objective: The objective was to quantify genetic and environmental influences on variations in energy and macronutrient intakes among children aged 9 years.

Design: We conducted a nutrition study among children participating in the Quebec Newborn Twin Study, a population-based birth cohort of twins.

Genetic and environmental influences on daytime and nighttime sleep duration in early childhood.

Objectives: To determine the relative contributions of genetic and environmental factors on daytime and nighttime continuous sleep duration at 6, 18, 30, and 48 months of age, and to identify different subgroups of children who followed different daytime and nighttime sleep duration trajectories and to investigate their etiology.

Methods: The current study included 995 twins (405 monozygotic and 586 dizygotic) of the Quebec Newborn Twin Study recruited from the birth records of the Quebec Statistics Institute. Daytime and nighttime sleep was assessed through maternal reports at 6, 18, 30, and 48 months of age.

Strong genetic contribution to peer relationship difficulties at school entry: findings from a longitudinal twin study.

This study assessed the genetic and environmental contributions to peer difficulties in the early school years. Twins' peer difficulties were assessed longitudinally in kindergarten (796 twins, Mage = 6.1 years), Grade 1 (948 twins, Mage = 7.

The Quebec Newborn Twin Study into adolescence: 15 years later.

The Quebec Newborn Twin Study (QNTS) is an ongoing prospective longitudinal follow-up of a birth cohort of twins born between 1995 and 1998 in the greater Montreal area, Québec, Canada. The goal of QNTS is to document individual differences in the cognitive, behavioral, and social-emotional aspects of developmental health across childhood, their early bio-social determinants, as well as their putative role in later social-emotional adjustment, school and health outcomes. A total of 662 families of twins were initially assessed when the twins were aged 6 months.

Genetic and environmental contributions to weight, height, and BMI from birth to 19 years of age: an international study of over 12,000 twin pairs.

Objective: To examine the genetic and environmental influences on variances in weight, height, and BMI, from birth through 19 years of age, in boys and girls from three continents.

Design And Settings: Cross-sectional twin study. Data obtained from a total of 23 twin birth-cohorts from four countries: Canada, Sweden, Denmark, and Australia.

Gene-environment processes linking aggression, peer victimization, and the teacher-child relationship.

Aggressive behavior in middle childhood is at least partly explained by genetic factors. Nevertheless, estimations of simple effects ignore possible gene-environment interactions (G × E) or gene-environment correlations (rGE) in the etiology of aggression. The present study aimed to simultaneously test for G × E and rGE processes between aggression, on the one hand, and peer victimization and the teacher-child relationship in school, on the other hand.

Altered patterns of brain activity during transient sadness in children at familial risk for major depression.

Introduction: We used functional magnetic resonance imaging (fMRI) to investigate the neural correlates of sadness, the prevailing mood in major depression (MD), in a prospective, well-documented community sample followed since birth.

Methods: The children, comprising 136 children (65 boys and 71 girls) of mothers with varying levels of depressive symptomatology, were scanned - using a 1.5-Tesla system - while they watched 5 blocks of both sad and neutral film excerpts.

Salivary cortisol levels are associated with resource control in a competitive situation in 19 month-old boys.

Glucocorticoids (GCs) have been related to social rank in many studies across species, a particular rank giving rise to a particular stress-related physiological profile. Our aim was to examine the hypothesis that GCs levels in toddlers would be related to social dominance in a competitive resource situation. Subjects were 376 toddlers from the Quebec Newborn Twin Study.

Neuroanatomy of childhood disruptive behavior disorders.

Our aims were to (1) examine possible neuroanatomical abnormalities associated with the Disruptive Behavior Disorders (DBDs) as a group and (2) assess neuroanatomical anomalies specific to each DBD (i.e., conduct disorder [CD] and oppositional defiant disorder).

A monozygotic twin difference study of friends' aggression and children's adjustment problems.

This study used the monozygotic (MZ) twin difference method to examine whether differences in friends' aggression increased the differences in MZ twins' aggression and depressive symptoms from kindergarten to Grade 1 and whether perceived victimization by the friend played a mediating role in this context. Participants were 223 MZ twin pairs. Results showed that differences in kindergarten friends' aggression significantly predicted an increased difference in MZ twins' aggression from kindergarten (mean age = 6.

Genetic and environmental influences on structural variability of the brain in pediatric twin: deformation based morphometry.

Twin studies are one of the most powerful study designs for estimating the relative contribution of genetic and environmental influences on phenotypic variation inhuman brain morphology. In this study, we applied deformation based morphometry, a technique that provides a voxel-wise index of local tissue growth or atrophy relative to a template brain, combined with univariate ACE model, to investigate the genetic and environmental effects on the human brain structural variations in a cohort of homogeneously aged healthy pediatric twins. In addition, anatomical regions of interest (ROIs) were defined in order to explore global and regional genetic effects.

Genetic and environmental etiology of disregard for rules.

Disregard for rules, a key component of oppositional defiant and conduct disorders, is stable during early childhood. This study investigates for the first time the relative importance of genetic and environmental factors underlying this early developmental stability. Maternal reports of child disregard for rules were obtained at four time points from 20 to 64 months of age in a population-based twin sample (N = 597 twin pairs, including 238 monozygotic and 359 dizygotic pairs).

Early impact of 5-HTTLPR polymorphism on the neural correlates of sadness.

Healthy adults carrying the short (S) allele of the human serotonin transporter gene linked polymorphism (5-HTTLPR) show increased amygdala activation during visual processing of emotionally negative stimuli compared to healthy adults homozygous for the long (L) allele. To determine whether abnormal brain responses during negative emotion appear early in life in S allele carriers, functional magnetic resonance imaging (fMRI) was used to measure brain activity during a transient state of sadness in children carrying the S allele (S group) or homozygous for the L allele (L group). Blood-oxygen-level dependent (BOLD) signal changes were measured while subjects viewed blocks of neutral film excerpts and sad film excerpts.

Prenatal alcohol exposure and cortisol activity in 19-month-old toddlers: an investigation of the moderating effects of sex and testosterone.

Rationale: Early exposure to stress and teratogenic substances have an impact on brain structures involved in cognition and mental health. While moderate-to-high levels of prenatal alcohol exposure (PAE) have repeatedly been associated with long-term neurodevelopmental deficits, no consensus has yet been reached on the detrimental effects of low-to-moderate PAE on the children's functioning, including the limbic-hypothalamic-pituitary-adrenal axis.

Objectives: The study aims to examine the association between low PAE and cortisol response to unfamiliar situations in 19-month-old children and to determine whether this association was moderated by sex and testosterone levels.

Interactive links between theory of mind, peer victimization, and reactive and proactive aggression.

This study investigated the relation between theory of mind and reactive and proactive aggression, respectively, as well as the moderating role of peer victimization in this context. The 574 participants were drawn from a longitudinal study of twins. Theory of mind was assessed before school entry, when participants were 5 years old.

Lateralized genetic and environmental influences on human brain morphology of 8-year-old twins.

It has been increasing rapidly interest in understanding genetic effects on brain structure and function in recent years. In this study, we examined the genetic and environmental influences on the variation in cortical thickness and specific tissue volumes in a large cohort of 8-year-old healthy twins. The present study can provide a better estimation of the genetic and environmental effects by virtue of the homogeneously aged pediatric twin pairs with a similar growing environment.

Early child language mediates the relation between home environment and school readiness.

Home environment quality is a well-known predictor of school readiness (SR), although the underlying processes are little known. This study tested two hypotheses: (a) child language mediates the association between home characteristics (socioeconomic status and exposure to reading) and SR, and (b) genetic factors partly explain the association between language and SR. Data were collected between 6 and 63 months in a large sample of twins.

Gene-environment interplay between peer rejection and depressive behavior in children.

Background: Genetic risk for depressive behavior may increase the likelihood of exposure to environmental stressors (gene-environment correlation, rGE). By the same token, exposure to environmental stressors may moderate the effect of genes on depressive behavior (gene-environment interaction, GxE). Relating these processes to a peer-related stressor in childhood, the present study examined (1) whether genetic risk for depressive behavior in children is related to higher levels of rejection by the peer group (rGE) and (2) whether peer rejection moderates the effect of genetic factors on children's depressive behavior (GxE).