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Subcortical-PFC resting state connectivity
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Introduction
The contributions of limbic brain regions and the prefrontal cortex (PFC) to enhanced coordination in affective/motivational behaviors change considerably from childhood to adulthood (van Duijvenvoorde et al., 2016b). Resting State functional MRI (RS-fMRI) studies on limbic/subcortical-cortical functional brain connectivity in adults have provided insights into the connectivity patterns between different limbic/subcortical (sub) regions and the PFC, with positive connectivity between limbic/subcortical regions and affective PFC regions, and negative connectivity between limbic/subcortical regions and dorsal control regions of the PFC (Di Martino et al., 2008; Roy et al., 2009; Choi et al., 2012). Despite the consistent findings in general connectivity patterns in adults, not much is known about the robustness of these effects in children, and the role of genetic and environmental influences on limbic/subcortical- PFC brain connectivity. To date, the size of environmental and genetic contributions to limbic/subcortical-PFC connectivity has not been examined in children. In this study, we therefore investigated the robustness of findings regarding limbic/subcortical-PFC functional brain connectivity in childhood, and the heritability of these connections in 7-to-9-year-old twins (N=220). The current paper is the first to investigate childhood RS connectivity in two independent samples and additionally explore genetic and environmental influences on that connectivity, thereby providing important insights in the underlying mechanisms of functional brain connectivity in childhood.
RS-fMRI studies in adults have shown that the striatum is functionally connected to distributed regions throughout the entire brain, including motor, cognitive, and affective systems (Di Martino et al., 2008; Barnes et al., 2010; Choi et al., 2012). Different sub regions within the striatum show distinct functional connectivity patterns (Di Martino et al., 2008; Choi et al., 2012). A pioneering study of Choi et al. (2012) revealed distinct cortical-connectivity for five different sub regions in the striatum. For example, a dorsal sub region of the striatum was mainly connected to a network of the dorsolateral PFC (dlPFC), the dorsal medial PFC (dmPFC), and parietal regions, whereas a more ventral sub region of the striatum was primarily connected to medial/orbitofrontal regions of PFC (Di Martino et al., 2008; Choi et al., 2012). In the current study we focused on the ventral striatum, since this striatal sub region is consistently implicated in affective/motivational behavior (Haber and Knutson, 2010). Adult studies revealed that the ventral striatum is positively connected to limbic-affective regions such as the ventral medial PFC (vmPFC), the ventral anterior cingulate cortex (vACC), the orbitofrontal cortex (OFC), and the insula (Di Martino et al., 2008; Choi et al., 2012). In contrast, negative connectivity has been reported between the ventral striatum and cortical regions related to cognitive control, such as the dlPFC, the dorsal anterior cingulate cortex (dACC), the parietal cortex, and the precuneus (Di Martino et al., 2008). The amygdala also shows negative
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