Distraction attenuates goal-directed neural responses for food rewards
Distracted eating can lead to increased food intake, but it is unclear how. We hypothesized that distraction affects the change in motivated responses for food reward after satiation. To investigate this, 38 healthy normal-weight participants (28F, 10M) performed a detection task varying in attentional load (high or low distraction) during fMRI. Simultaneously, they exerted effort for food rewards (sweet or savory) by repeated button presses. Two fMRI runs were separated by outcome devaluation (satiation) of one of the reward outcomes, to assess outcome-sensitive, i.e. goal-directed, responses. Behavioral results showed no effect of distraction on effort for food reward following outcome devaluation. At an uncorrected threshold (p<0.001), distraction decreased goal-directed responses (devalued versus valued) in the right inferior frontal gyrus (rIFG). Importantly, these distraction-sensitive rIFG responses correlated negatively (r = - 0.40, p = 0.014) with the effect of distraction on the number of button presses. Specifically, decreased rIFG responses due to distraction related to increased button presses for food reward after satiation, in line with the rIFGs established role in response inhibition. Furthermore, distraction decreased functional connectivity between the rIFG (seed) and left putamen for valued versus devalued food rewards (pFWE(cluster)<0.05). Our results suggest that distraction attenuates the ability to inhibit responses for food reward after satiation by affecting the rIFG. Furthermore, distraction attenuated connectivity between two regions involved in response inhibition - rIFG and putamen - after outcome devaluation. These results may explain why distraction can lead to overeating in our current, distracting, environment. The study was preregistered at: https://osf.io/ad2qk.