Insulin sensitivity and brain reward activation in overweight Hispanic girls: a pilot study

Insulin resistance is a link between obesity and the associated disease risk. In addition to its role as an energy regulatory signal to the hypothalamus, insulin also modulates food reward.

To examine the relationship of insulin sensitivity (SI) and fasting insulin with cerebral activation in response to food and non-food cues in children.

Twelve overweight Hispanic girls (age: 8-11) participated in two study visits, a frequently sampled intravenous glucose tolerance test and a functional neuroimaging session (GE HDxt 3.0Tesla) with visual stimulation tasks. Blocks of images (high calorie [HC], low calorie [LC] and non-food [NF]) were presented in randomized order.

Comparing HC with NF, SI was inversely associated with activation in the anterior cingulate (r(2)  = 0.65; P < 0.05), the insula (r(2)  = 0.69; P < 0.05), the orbitofrontal cortex (r(2)  = 0.74; P < 0.05), and the frontal and rolandic operculum (r(2)  = 0.76; P < 0.001). Associations remained significant after adjustment for body mass index. Association of fasting insulin and cerebral activation disappeared after adjustment for waist circumference.

In addition to weight loss, insulin sensitivity may pose an important target to regulate neural responses to food cues in the prevention of excessive weight gain.