Results:

Food images induced brain responses in the hypothalamus, striatum, amygdala, insula, ventromedial prefrontal cortex (PFC), dorsolateral PFC and occipital lobe (whole brain correction, P< 0.05). Wanting (P< 0.001) and liking (P< 0.001) ratings were significantly higher for the food than the non-food images, but not different between insulin and saline infusion groups. Hunger ratings increased throughout the MRI scan and correlated with preference for high-calorie food pictures (r= 0.70; P< 0.001). However, neither brain activity nor food cravings were affected by hyperinsulinemia or hormonal status (leptin and ghrelin levels)(P= NS).

ConclusionS:

Our data demonstrate that visual food cues induce a strong response in motivation/reward and cognitive-executive control brain regions in non-obese subjects, but that these responses are not diminished by hyperinsulinemia per se. These findings suggest that our modern food cue saturated environment may be sufficient to overpower homeostatic hormonal signals, and thus contribute to the current obesity epidemic.