PT  - JOURNAL ARTICLE
AU  - Selin Neseliler
AU  - Uku Vainik
AU  - Mahsa Dadar
AU  - Yvonne H.C. Yau
AU  - Isabel Garcia-Garcia
AU  - Stephanie G. Scala
AU  - Yashar Zeighami
AU  - D. Louis Collins
AU  - Alain Dagher
TI  - Neural and behavioral endophenotypes of obesity
AID  - 10.1101/348821
DP  - 2018 Jan 01
TA  - bioRxiv
PG  - 348821
4099  - http://biorxiv.org/content/early/2018/06/16/348821.short
4100  - http://biorxiv.org/content/early/2018/06/16/348821.full
AB  - BackgroundImpulsivity is a risk factor for obesity. It has different underlying facets that can be assessed using questionnaires. Impulsivity can be further refined by the use of food-specific questionnaires, which measure a tendency to uncontrolled eating. We examined how these impulsivity measures relate to each other, to obesity, and to brain anatomy.MethodsWe assessed students in their first year of university - a risky period for weight gain- at the beginning (N = 2214) and at the end of the school year (N = 1145) using questionnaire measures of impulsivity, personality, stress reactivity and eating-specific traits. A subset of participants (N = 72) underwent T1-weighted MRI to investigate the brain correlates of impulsivity.ResultsUsing factor analysis, we show that impulsivity can be stratified into three domains, which we label stress reactivity, reward sensitivity and self-control, while eating questionnaires resolve into a single latent factor - uncontrolled eating. A watershed model shows that uncontrolled eating mediates the effect of impulsivity traits on BMI. Self-control and stress reactivity scores are associated with a thinner lateral orbitofrontal cortex. In addition, stress reactivity correlates positively with amygdala and negatively with hippocampal volume. Longitudinally, lack of self-control, not uncontrolled eating, correlates with weight gain, while stress reactivity correlates with weight loss in male students.ConclusionsThe brain-impulsivity-obesity relationship is hierarchical. Structural brain differences relate to differences in impulsivity domains which affect BMI via uncontrolled eating. However, longitudinally, low self-control, not uncontrolled eating, is a predictor of weight gain in this sample.