Both the reward circuitry and the brain prefrontal networks relevant to top-down regulation play an important role in appetite regulation. Prior work showed that neural responses to food cues in the nucleus accumbens (NAc) and orbital frontal cortex (OFC) predicted subsequent increases in body mass index (BMI) in adults and adolescents. It remains unknown whether food cue reactivity in reward regions and/or prefrontal inhibition regions would predict future increases in BMI in children.
Thirty-six children (age: 8.29±0.73 years; sex: 11 boys and 25 girls; BMI range:13.8~34 kg/m2) completed a MRI session at baseline where they viewed appetizing food cues and neutral non-food cues (as a control). A priori region-of-interests included the NAc, OFC, and dorsolateral prefrontal cortex (dlPFC). Height and weight were measured at baseline and 1-year follow up visit. Behavioral food responsiveness was additionally measured at baseline visit using child eating behavioral questionnaire.
The average increase in BMI over a 1-year period was 0.68± 1.04 kg/m2 (range: -1.46~3.27 kg/m2). Smaller dlPFC response to food vs. non-food cues was significantly correlated with a greater BMI increase (r=-0.34, P=0.045), and this result remained significant after adjusting for age, sex and baseline BMI (P=0.01). There was a marginally significant negative relationship between dlPFC food cue reactivity and behavioral food responsiveness (r=-0.37, P=0.085). Although it was not significant, there was a trend of greater NAc food cue reactivity associated with a greater increase in BMI (r=0.26, P=0.13).
Our results suggest that children who show hypo-activation in the dlPFC during observation of appetitive food cues may be at increased risk for weight gain. The dlPFC may play an important role in top down regulation of eating behavior.