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                                Chapter 6
 connectivity with dorsal cortical regions, including the dlPFC, dACC, dmPFC, the parietal cortex, and to the cerebellum (Roy et al., 2009). The positive connectivity patterns from the amygdala are ventrally oriented, including the vmPFC, the rostral ACC, and the OFC, but also more temporally oriented, towards the insula and inferior frontal gyrus (IFG) (Stein et al., 2007; Roy et al., 2009).
The development of limbic/subcortical-prefrontal cortex functional brain connectivity from childhood to adulthood has also been studied with RS-fMRI (e.g., Fareri et al. (2015), Gabard-Durnam et al. (2014), van Duijvenvoorde et al. (2016a)). Developmental studies consistently report an overall shift from local limbic/subcortical-subcortical connectivity in childhood towards more distributed long-range limbic/subcortical-cortical connectivity in adulthood (Fair et al., 2009; Vogel et al., 2010; Menon, 2013; Rubia, 2013). However, this age- related shift from local to distributed connectivity was called into question after several studies had shown that these developmental changes were largely influenced by age-related changes in head-motion (Van Dijk et al., 2010; Power et al., 2012). That is to say, head motion can result in substantial changes in RS- fMRI connectivity (Van Dijk et al., 2010; Power et al., 2012). Specifically, volume- to-volume micro movement (i.e., head motion between two frames) can overestimate short-distance connectivity and underestimate long-distance connectivity (Satterthwaite et al., 2013). Young children usually have more difficulty lying still, resulting in more volume-to-volume micro movement, which may have resulted in an underestimation of subcortical-cortical brain connectivity in childhood. Therefore, there is a need to better understand connectivity patterns in childhood, using large samples and replication designs.
The PFC gradually develops both structurally and functionally until maturation in early adulthood (Lenroot and Giedd, 2006; van Duijvenvoorde et al., 2016a). Both the striatum and the amygdala show plasticity to the environment (for a review, see Tottenham and Galvan (2016)). For example, caregiving adversity during childhood (neglect, institutional care or low parental warmth) has been associated with amygdala hyper reactivity during adolescence (Tottenham et al., 2011; Garrett et al., 2012; Casement et al., 2014). In addition, adults and adolescents with a history of childhood stress show less striatum activity when receiving a monetary reward (Goff et al., 2013; Boecker et al., 2014; Hanson et al., 2016). Given these environmental influences on ventral striatum and amygdala activity, the connectivity between these limbic regions and cortical PFC regions may also be influenced by environmental factors. Alternatively, the high commonality of psychiatric disorders that rely on limbic/subcortical-PFC connections in families may suggest a heritability factor as well (Bouchard and McGue, 2003; Flint and Kendler, 2014). It is important to note that heritability estimates for brain anatomy and connectivity differ across development such that heritability estimates are stronger in adulthood than in childhood (Lenroot et al., 2009; van den Heuvel et al., 2013).
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