This thesis had two main focuses. First, it investigated the mechanisms underlying individual differences in brain structure, developmental changes, and function. Second, it examined how enriched... Show moreThis thesis had two main focuses. First, it investigated the mechanisms underlying individual differences in brain structure, developmental changes, and function. Second, it examined how enriched and deprived environments affect brain development from middle childhood to early adolescence (ages 7-14). The study revealed distinct genetic and environmental influences on the developing brain during this period. Genetic contributions largely explained the variations in brain structure and developmental changes, along with location-specific environmental factors. While studies on genetic and environmental influences on brain regions showed both overlapping and unique outcomes, the interplay between these influences is complex. Using MRI and fMRI provided a comprehensive understanding of how individual differences arise. Additionally, the thesis highlighted the distinct effects of specific environmental influences on brain development. An enriched cognitive environment, such as musical ability, was linked to attenuated development, while a deprived environment, exemplified by the COVID-19 pandemic, accelerated development. Notably, the brain showed resilience to adverse effects, particularly in TPJ growth during the pandemic, suggesting adaptive processes during this developmental phase. Future research should explore whether the relationship between environmental effects and brain maturation pace is linked to positive mental health outcomes. Ultimately, identifying interventions to ensure all children thrive throughout their development is crucial. Show less
This thesis deals with various aspects of twin anemia polycythemia sequence (TAPS). TAPS is a condition that can develop due to unbalanced feto-fetal blood transfusion through minuscule vascular... Show moreThis thesis deals with various aspects of twin anemia polycythemia sequence (TAPS). TAPS is a condition that can develop due to unbalanced feto-fetal blood transfusion through minuscule vascular placental anastomoses in monochorionic twin pregnancies, causing the donor twin to become anemic and the recipient twin to become polycythemic. In this thesis we show that a difference in middle cerebral artery peak systolic velocity (MCA-PSV) > 0.5 Multiples of the Median (MoM) has a high diagnostic accuracy for the the antenatal diagnosis of TAPS. For postnatal diagnosis of the condition, inspection of the color of the maternal side of the placenta can be of great value. Furthermore, we present the results of a large international registry, and report on outcomes after different treatment options for TAPS. As the best treatment for TAPS is unclear, we propose the protocol of The TAPS Trial (a multicenter open-label international RCT) to investigate the potential beneficial effect of fetoscopic laser surgery for the outcome in TAPS twins . In the last chapters of this thesis we discuss short- and long-term outcome and show that TAPS donors show significantly higher rates of perinatal mortality and long-term neurodevelopmental impairment than their recipient co-twins. Show less
Meulen, M. van der; Wierenga, L.M.; Achterberg, M.; Drenth, N.; IJzendoorn, M.H. van; Crone, E.A. 2020
Prosocial behavior and empathy are important aspects of developing social relations in childhood. Prior studies showed protracted structural development of social brain regions associated with... Show moreProsocial behavior and empathy are important aspects of developing social relations in childhood. Prior studies showed protracted structural development of social brain regions associated with prosocial behavior. However, it remains unknown how structure of the social brain is influenced by genetic or environmental factors, and whether overlapping heritability factors explain covariance in structure of the social brain and behavior. The current study examined this hypothesis in a twin sample (aged 7-9-year; N = 512). Bilateral measures of surface area and cortical thickness of the medial prefrontal cortex (mPFC), temporo-parietal junction (TPJ), posterior superior temporal sulcus (pSTS), and precuneus were analyzed. Results showed genetic contributions to surface area and cortical thickness for all brain regions. We found additional shared environmental influences for TPJ, suggesting that this region might be relatively more sensitive to social experiences. Genetic factors also influenced parent-reported prosocial behavior (A = 45%) and empathy (A = 59%). We provided initial evidence that the precuneus shares genetically determined variance with empathy, suggesting a possible small genetic overlap (9%) in brain structure and empathy. These findings show that structure of the social brain and empathy are driven by a combination of genetic and environmental factors, with some factors overlapping for brain structure and behavior. Show less
To thrive as an individual and within society, children need to master the ability to control their behavior and adapt it to social rules and standards. They also need to acquire the social... Show moreTo thrive as an individual and within society, children need to master the ability to control their behavior and adapt it to social rules and standards. They also need to acquire the social competence to interact and communicate with others. Studies showing the relevance of behavioral control and social competence for children’s future development give rise to the search for factors that are associated with these competencies. These factors can be characteristics of the child, factors within the child’s social environment, and factors within the physical and socioeconomic environment. In the current thesis we aimed to identify some of these factors associated with the development of behavioral control in early childhood, and with prosocial behavior in early to mid-adolescence. We assessed four types of behavioral control: parent-reported effortful control, observed cheating behavior, delay of gratification, and response inhibition. For prosocial behavior, one type was assessed: observed compensating behavior towards an excluded peer. The results show that there is quite some variation in children’s level of behavioral control as well as in adolescents’ level of prosocial behavior and that these levels can be related to child characteristics, factors in their social environment, physical, and socioeconomic environment in a meaningful way. Show less
This is the first behavior genetic study of salivary -amylase (sAA), focusing on genetic and environmental influences on stability and change in sAA during baseline and exposure to infant crying.... Show moreThis is the first behavior genetic study of salivary -amylase (sAA), focusing on genetic and environmental influences on stability and change in sAA during baseline and exposure to infant crying. The sample consisted of 184 adult twin pairs. Although there was significant variation between individuals in basal levels of sAA and in responsivity to infant crying, strong stability in sAA concentrations across conditions was found. Similar genetic mechanisms influenced sAA at baseline and in response to cry sounds (explained variance: 51–62%), accounting for part of the stability in sAA. Unique environmental factors explained the remaining variance in sAA, some of them only emerging in response to the cry sounds, explaining individual differences in the pattern of reactivity. These findings confirm that sAA is sensitive to the effects of potentially stressful stimuli (state variance) and at the same time demonstrate its relative robustness and stability across time and conditions (trait variance). Show less
