Page 107 - Like me, or else... - Michelle Achterberg
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                                Heritability of aggression following social evaluation
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 information (Apps et al., 2016; Lee and Seo, 2016), and both play important roles in social cognition and behavior (Blakemore, 2008). Our results suggest that whereas the ACCg signals for social salient cues, the mPFC might signal for social threatening cues. Positive feedback, on the other hand, resulted in heightened activation in the caudate, SMA and bilateral DLPFC, which is consistent with previous social evaluation paradigms that reported increased activation in striatum (Davey et al., 2010; Gunther Moor et al., 2010b; Guyer et al., 2012), superior frontal gyrus/SMA (Gunther Moor et al., 2010b; Guyer et al., 2012), and middle frontal gyrus /DLPFC (Gunther Moor et al., 2010b).
Interestingly, SMA and DLPFC activity were also associated with aggressive behavior on the task. SMA and DLPFC activations were related to aggression after negative (relative to neutral and/or positive) feedback. Post hoc visualization of PE values showed that children who were more aggressive after negative feedback showed relatively less activation of the DLPFC during negative feedback compared to positive social feedback. This is in line with prior studies in adults which showed that more DLPFC activity after negative social feedback was related to less subsequent aggression (Riva et al., 2015; Achterberg et al., 2016b). It should be noted, however, that we did not observe brain-behavior associations when we performed whole brain regression analyses, in contrast to earlier studies in adults (Achterberg et al., 2016b). Moreover, our brain-behavior associations on ROIs did not survive Bonferroni correction. The DLPFC is one of the brain regions that take longest to mature (Sowell et al., 2001; Gogtay et al., 2004), leaving ample room for individual, developmental differences. Although our sample size was fairly large compared to previous fMRI studies, individual developmental differences are best captured with longitudinal designs, due to individual variation in the timing of brain maturation.
We did not find significant brain-behavior associations in other ROIs (caudate, IFG, insula, mPFC, ACCg) that responded to social peer feedback. The lack of brain-behavior associations might indicate that these regions signal for social cues, but are not sensitive to retaliation behaviors. Indeed previous studies have indicated the IFG, insula, mPFC and ACCg as important regions of the “social brain” (for reviews, see Blakemore (2008) and Adolphs (2009)). The social brain is defined as a network of brain regions that is activated when we evaluate others and think about others’ intentions and feelings (Brothers, 1990; Blakemore, 2008). Activation in these regions during peer feedback evaluation could indicate that children evaluate the intentions of the peers, but might not be specifically related to the actions they intent towards that peer. Regions that did show a relation with aggression, namely the SMA and DLPFC, have indeed been shown to be associated with behavioral motor planning (SMA) and behavioral control (DLPFC) in previous research (Riva et al., 2015; Achterberg et al., 2016b).
Genetic modeling showed that genetics played a role in activation in the DLPFC, the SMA and the right caudate, with 10-14% of the variance explained by genetics. Previous heritability studies on structural brain measures have focused
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