Page 99 - Like me, or else... - Michelle Achterberg
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                                Heritability of aggression following social evaluation
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 Neural analyses
Whole brain analyses
To investigate the general valence effects of social feedback, we examined neural activity for positive versus neutral and negative versus neutral feedback using a conjunction analysis. We found common activation across positive and negative feedback in a wide network of regions including left and right insula, the ACCg, and the lateral occipital cortex (Figure 2a and Table 3).
To investigate effects of negative versus positive social feedback, we investigated the contrasts negative>positive and positive>negative. The contrast negative>positive feedback resulted in activation with local maxima in the medial PFC, the left and right inferior frontal gyrus (IFG), and the occipital pole (Figure 2b and Table 3). The reversed contrast positive>negative resulted in increased activation in the left and right orbitofrontal cortex (OFC), the precuneus, the supplementary motor cortex (SMA), the right caudate, the left and right DLPFC, and the lingual gyrus (Figure 2c and Table 3). Results did not change after exclusion of children with an Axis-I disorder (Table S3).
Brain-behavior analyses
To investigate possible brain-behavior associations in the clusters from the whole brain contrasts 10 ROIs were selected based on a priori hypotheses to predict behavioral aggression using least square regressions with HCSE. We chose 3 ROIs from the conjunction (the ACCg, the left insula, and the right insula), 3 ROIs from the contrast negative>positive (the mPFC, the left IFG, and the right IFG) and 4 ROIs from the contrast positive>negative (the SMA, the right caudate, the left DLPFC, and the right DLPFC) (Table 3). We focused on associations with noise- blast difference scores following negative social feedback (negative-positive and negative-neutral, corrected for age and IQ). We observed a significant association between noise blast differences and activity in left DLPFC, right DLPFC activation, and SMA activation (Table 4, Figure 3). These associations showed that greater activation during positive (versus negative) social evaluation was associated with more aggression after negative social feedback, see Figure 3a-d. To visualize this effect in more detail, we plotted the PE’s of the right DLPFC for participants with low aggression after negative feedback and participants with high aggression after negative feedback (Figure 3e). Groups were based on a median split of the noise-blast difference scores following negative social feedback (negative- positive, corrected for age and IQ). Participants who differentiated more in aggression (larger noise blast difference positive versus negative feedback) also differentiated more on a neural level (brain activation after positive versus negative feedback), see Figure 3e. In other words, participants who showed less DLPFC activity during negative feedback relative to positive feedback, were more aggressive after negative feedback. These associations did, however, not survive Bonferroni correction (p’s > 0.025).
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