For the second section of the study, the strength of functional connectivity between NAcc and every other voxel in the brain was correlated with indices of the delay discounting task. The task measures impulsive choice by evaluating the intolerance to delay-of-gratification, or delay-discounting, proposed to be a core dysfunction in ADHD (Sagvolden et al., 1998; Sonuga-Barke, 2005). 133 children were presented a computerized task also utilized by Wilson and colleagues (Wilson et al., 2011) and based on the task described by Mitchell (1999). The task consisted of 91 questions for which children had to choose between smaller amounts of hypothetical money now and hypothetical $10.00 after a varying delay. Most of the participants completed a task with four hypothetical delays of 7, 30, 90, 180 days (126 subjects); a small number had four different delays of 1, 7, 30, 90 days (5 subjects); and two participants had five delays of 7, 30, 90, 180, 365 days delays. These variations did not affect results as explained later.
