Validation of a child-friendly version of the monetary incentive delay task

Abstract

The monetary incentive delay (MID) task (Knutson, 2000) is an imaging paradigm used to measure neural activity of incentive receipt anticipation. The task reliably elicits striatal activation and is commonly used with both adult and adolescent populations, but is not designed for use with children. In the current article, we present data on the newly designed 'piñata task' a child-friendly analog of the MID task. We demonstrate the task can be used successfully in children to study the neural correlates of anticipatory incentive processing. Results from a behavioral study and a neuroimaging study are reported. In Study #1, a sample of 8- to 14-year-old children demonstrates expected behavioral effects: subjects responded most quickly and most accurately on trials with greater potential rewards; older children displayed faster reaction times than younger. In Study #2, 8- to 12-year-old children showed neural activation patterns consistent with those seen in adults in the MID task: activation was modulated by cue incentive value in reward-processing regions, including the striatum, thalamus, mesial prefrontal cortex and insula. Study results suggest that the piñata task is a valid analog of the MID task, and can be used to assess neural correlates of reward processing in children as young as 8-9 years of age.

Keywords: Reward; childhood; fMRI.

Fig. 1

Trial structure of the piñata task.

Fig. 2

Whole-brain fMRI results. Regions showing parametric incentive cue-based activation, P < 0.005. x = 3.

Fig. 3

Striatal ROI fMRI results. Parametric incentive cue-based activation in both anterior and posterior striatum, P < 0.005. Left is left.

Fig. 4

Activation in the caudate head by cue type.

Fig. 5

Salience-related changes in mean caudate head activation by age.