2.3 Emotion regulation task
Participants completed an adapted emotion regulation task43,44 during fMRI scanning. During the task (Figure 1 ), participants viewed distress-inducing stimuli and rated their current emotional distress after each trial. Participants rated their distress on a 1-6 visual analog scale (VAS; 1=“No distress at all”, 6=“Worst possible distress”) using an adapted version of the FACES scale.45,46 Task stimuli consisted of ten validated 30 s video clip vignettes depicting various realistic, salient stressors (e.g., child receiving an injection) that have been shown to induce transient distress in children.47 Negative stimuli were used to test for differences in brain response to distress-inducing stimuli. Participants were explicitly instructed to pay attention to the movie as if it were real, pretend they were the child in the movie, and react as if they were in that situation. Prior to each video clip, participants were given instructions for one of four conditions: (1) focused attention to breath, BREATH, (2) mindful acceptance, ACCEPT, (3) distraction, DISTRACT, or (4) passive viewing, LOOK (Supplemental Methods 1.2). Participants were cued using the text and visual cue during the task in the fMRI scanner. Each trial lasted 30 s, and included a 2 s instruction slide, a 30 s video clip, and a 5 s emotion rating period (Figure 1 ). The inter-trial interval (2 s) was a “RELAX” screen. There were 5 trials of each of the 4 conditions, for a total of 20 trials (total time=13 min, 21 sec). Video clips were counterbalanced across conditions. Presentation software (Neurobehavioral Systems, Inc.) was used for stimulus presentation and behavioral data acquisition. The task was displayed on a back-projection screen affixed to the head coil and behavioral responses were registered using a 2x2 MR-compatible response device.