Brain Activation by Visual Food-Related Stimuli and Correlations with Metabolic and Hormonal Parameters: A fMRI Study

Regional brain activity in 15 healthy, normal weight males during processing of visual food stimuli in a satiated and a hungry state was examined and correlated with neuroendocrine factors known to be involved in hunger and satiated states. Two functional Magnetic Resonance Imaging (fMRI) sessions were performed with a one week interval, after overnight fasting or 1 hour after a standardized meal. Blood samples and appetite assessment were obtained after each fMRI session. Main effects of processing food versus non-food stimuli were observed in the ventral visual stream, including the fusiform gyrus and hippocampal areas bilaterally, significantly more in the fasting state. Leptin concentration correlated negatively with activity in the left hippocampal area and right insula during the satiation condition. A positive correlation between ghrelin and “thought of food” hunger scores were found. The positive correlation between ghrelin and food related activation in the insula areas and the right hippocampus during fasting did not reach significance. Conclusion: The increased activation of food vs non-food pictures in the ventral visual stream reflects increased salience of food pictures when subjects are hungry. Leptin was associated with activations in areas involved in processing of new information and emotion.