Page 251 - Like me, or else... - Michelle Achterberg

Summary and general discussion
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separated by a 2-year interval. This sample was part of the 3-wave longitudinal Braintime study (van Duijvenvoorde et al., 2016b). First, I examined linear and non-linear development of both brain connectivity and behavior. The development of delay of gratification showed a quadratic trajectory, with a steep increase during late childhood and the peak in late adolescence. Structural brain connectivity showed cubic relations across development, with the most pronounced changes during late childhood and early adolescence. Moreover, age related increases in the preference for delayed rewards (i.e., less impulsive choice) were significantly dependent on a better quality of connections between the PFC and striatum. The longitudinal analysis revealed that stronger connectivity between striatum and PFC predicted less impulsive choices 2 years later, indicating that brain maturation precedes emotion regulation and behavioral outcomes. These findings fit well with neurocognitive models suggesting that striatum-prefrontal cortex maturation is an important factor contributing to the development of emotion regulation (Casey, 2015; Nelson et al., 2016).
Discussion
Taken together, the studies described in this thesis revealed several important findings. First, using the Social Network Aggression Task I was able to disentangle between neural activation that was specific for social rejection and social acceptance, and activity that was related to general social salience. Second, by including a retaliation component to the paradigm, I showed how individual differences in aggression regulation were related to differences in neural activation of the DLPFC. Third, by combining findings of task-based functional MRI with both functional and structural connectivity analyses, I gathered knowledge on the development of social emotion regulation and shed light on the important neural development that takes place during childhood. These three main outcomes are discussed in detail below and suggestions for a novel theoretical framework are provided.
Social pain, social gain and general social signaling
Prior studies on social evaluation processing have suggested that the ACC and AI might signal for social pain, as these regions showed increased neural activation after social rejection (Eisenberger and Lieberman, 2004; Kross et al., 2011; Rotge et al., 2015). However, several researchers have questioned this hypothesis as they reported increased activation of the ACC also in relation to expectancy violation (Somerville et al., 2006; Cheng et al., 2019), indicating these regions might signal for social salience in general (Dalgleish et al., 2017). The Social
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