Page 38 - Like me, or else... - Michelle Achterberg

Chapter 2
Neural activity: Whole brain and ROI analyses
The general contrast (all feedback conditions vs. baseline) showed a robust pattern of activation. Most regions that were active in the pilot sample could be confirmed in the test sample, and all regions that were active in the test sample were replicated in the replication sample (see Supplementary Materials). To test for differences between conditions, full factorial ANOVA’s were performed that were then decomposed by pair-wise comparisons. Moreover, we performed exploratory whole brain analyses in the combined test and replication groups (N=55), for which data were collected using the same MR scanner. Lastly, we performed ROI analyses in the three separate samples on three predefined ROIs: the amygdala (anatomically defined), the anterior insula and the mPFC/ACCg (based on Achterberg et al. (2016b)). To combine the results, we performed meta- analyses across the three samples for each of these ROIs.
Whole brain condition effects per sample
Pilot sample
All significant pairwise comparisons are displayed in Table 2. The contrasts positive>negative and positive>neutral feedback both resulted in one cluster of heightened activation in the lateral occipital cortex. The contrast negative > neutral feedback resulted in two significant clusters: one in the left lateral occipital cortex and one in the left orbitofrontal cortex, extending into the left insula.
Test sample
All significant pairwise comparisons are displayed in Table 2. The
contrasts positive>negative and positive>neutral feedback in the test sample also resulted clusters of heightened activation in the (lateral) occipital cortex. The contrast negative>neutral feedback resulted in two significant clusters, both in the lateral occipital cortex, extending into the fusiform gyrus.
Replication sample
All significant pairwise comparisons are displayed in Table 2. The contrasts positive>negative and positive>neutral feedback did not result in significant activation in the replication sample. Negative>positive feedback resulted in increased activation in the left inferior frontal gyrus, the left amygdala, and left lateral occipital cortex. Last, negative>neutral feedback resulted in increased activation of the left and right lateral occipital cortex, extending into the fusiform gyrus.
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