Computational protocol: The effect of social rank feedback on risk taking and associated reward processes in adolescent girls

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Protocol publication

[…] See for a detailed description of the image acquisition and preprocessing steps. Statistical analyses were performed on individual subjects’ data using the general linear model (GLM) in SPM8 (http://www.fil.ion.ucl.ac.uk). Trials were modeled as separate zero-duration events starting at the onset of stimulus presentation. Note that while each trial consisted of a stimulus, anticipation, and outcome phase, these phases were not modeled separately due to the absence of jittered periods in between the different phases within each trial. Feedback phases were also modeled as zero-duration events starting at the onset of feedback presentation. Transition phases were modeled as 12-s events starting at the onset of the transition screen presentation. Here, we report the results of analyses collapsed across the different trial types (LR-1pt, LR-3pts, HR-1pt, HR-3pts).We created two separate subject-specific design matrices to look at risk taking (choice model) and reward processing (outcome model), separately for the social rank and monetary feedback conditions. The choice model included four regressors of interest that modeled the trials based on the choices participants made, separately for each feedback type: Social Play, Monetary Play, Social Pass, and Monetary Pass. The outcome model included six regressors of interest that modeled the trials based on the outcomes participants experienced, separately for each feedback type: Social Gain, Monetary Gain, Social Loss, and Monetary Loss (for Play trials); Social Pass and Monetary Pass (for Pass trials). Note that the only difference between these two models is the further categorization of Play trials (in the choice model) into (i) play choices that resulted in gains, and (ii) play choices that resulted in losses (in the outcome model), which allowed for the comparison of Gain and Loss outcomes following the choice to play (separately for each feedback type). For each of these first-level statistical models, misses (trials on which participants failed to make a response within the allotted time) were modeled as a separate regressor of no interest. Additional regressors of no interest were included for (i) feedback phases, (ii) transition phases, and (iii–viii) the movement parameters (roll, pitch, yaw and displacement in superior, left and posterior directions). The feedback phases themselves were not analysed, since there were only eight instances of monetary and social rank feedback. More importantly, as noted earlier, we were interested in the influence of social ‘context’ on decisions and associated reward processes, not the influence of feedback per se.To examine group-level differences between the feedback types in risk taking-related brain activation, we conducted second-level statistical analyses to test the contrasts of Social vs Monetary Play and Social vs Monetary Pass. To examine group-level differences in reward-related brain activation associated with risk taking, we tested the contrasts of Social vs Monetary Gain and Social vs Monetary Loss (following the choice to play). Task-related responses were considered significant if they exceeded a family-wise error (FWE) corrected threshold of P < 0.05.To examine individual differences in choice and reward-related brain activation, we applied the MarsBar toolbox for use with SPM8 () to extract parameter estimates from specific regions of interest (ROIs). The NAc ROI was created by drawing 4 mm-radius spheres around the coordinates for bilateral NAc (x= ±10, y= 12, z = −3), as reported in . The mPFC ROI was defined by taking the entire functional cluster located in the mPFC that resulted from the Gain > Loss contrast calculated across the group (reported in ). To ensure the inspection of brain functioning within anatomical boundaries, additional masked ROIs were each created by taking the overlapping region of (i) the entire cluster of activation that resulted from the whole-brain results for the contrast of Social > Monetary Play trials (i.e. the functional ROI) and (ii) the anatomical ROI, available through the MarsBar anatomical automatic labeling (AAL) toolbox.To test whether differences in brain and behavior as a function of feedback type were related to differences in pubertal hormones, we correlated the parameter estimates extracted for each participant with individual (averaged) levels of testosterone and estradiol. We also looked at the relation of brain and behavior with other measures of development (age, pubertal stage and BMI) and self-reported resistance to peer influence. […]

Pipeline specifications

Software tools SPM, AAL
Applications Magnetic resonance imaging, Functional magnetic resonance imaging
Organisms Homo sapiens
Chemicals Estradiol