Background: The prevalence of adolescent obesity has increased drastically in the last few decades, spurring research examining causes and consequences of this chronic health condition. Neuroimaging techniques are being used to determine possible neural correlates of obesity that could help inform research in this field. However, the research among adolescents is not as abundant and findings so far are contradictory. This study sought to examine the association of the shape and volume of subcortical brain structures involved in reward processing with weight status in adolescent females. Additionally, this study sought to determine if the shape and volume of these structures were correlated with the Power of Food Scale (PFS), a self-report measure of food reward sensitivity. Method: The shape and volume of the nucleus accumbens (NAc) and amygdala were examined in 89 adolescent females ranging from normal weight to obese. MR scans were acquired using a high-resolution T1-weighted (MPRAGE) sequence. Shape was estimated using Large Deformation Diffeomorphic Metric Mapping. Seemingly unrelated regression models (SUM) were used for both brain structures with shape and volume as outcome variables and zBMI as the predictor variable. Pairwise correlation coefficients were determined for PFS score and both regions of interest (ROI). Results: SUM results revealed that zBMI was significantly associated with the shape of the left amygdala (β = -1.1, p<.021, 95% confidence interval [CI] = -2.02, -.16). When we controlled for age on the relationship between zBMI and left amygdala shape, we found the following partial correlation: r = -.24, p = .03. The PFS was found to have weak correlations with the volume and shape of the right NAc that approached significance (r = .20, p = .06; r = .19, p = .08, respectively). Conclusions: Our study suggests that there is an association between higher zBMI and aberrations in the shape of the left amygdala. We did not find associations between zBMI and the shape of our other reward-related ROIs, nor did we find any associations with zBMI and ROI volume. These findings suggest that variation in the shape of certain ROIs implicated in reward processing is associated with weight status in adolescents. Our findings also suggest that the shape and volume of the NAc could be a neural correlate of the PFS warranting further investigation. These findings may elucidate an important neural link between weight status and reward processing that could help to inform obesity research in adolescents.



College and Department

Family, Home, and Social Sciences



Date Submitted


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neuroimaging, obesity, adolescence, reward, amygdala, nucleus accumbens