Neurophysiological correlatives of eating behavior in obese children and adolescents

Objective: Searching for the neurophysiological background of the motivation of eating behavior we currently conduct a clinical trial with 45 obese children and adolescents and 20 age-related controls. Before and after multimodal therapy we acquired psychological data, event related potentials (ERP), functional MRI and peripheral physiological parameters. First results of ERP and peripheral physiology will be presented. Methods: Visual evoked ERP were recorded after picture presentation by using an 128-channel EEG system. We defined 4 categories of pictures with different semantic stimuli: foods, sports, in this regard neutral and emotional pleasant figures. In several trials we recorded peripheral data during picture viewing like electrodermal activity and heart rate changes. All subjects rated the pictures using standardized scales. Results: Comparing the groups we discovered distinct ERP differences particulary over the frontal brain areas between 300–500ms. Normal controls respond more frontal negativity to sports-related figures, while obese show enhanced negative potentials to food-related figures. Moreover, obese subjects also showed less heart rate deceleration to food cues than controls. Conclusions: These data suggest that obese children show stronger frontal activity during viewing of food cues that might be interpreted as the attempt to inhibit the desire to eat. Accordingly, obese children also exhibit less cardiac orienting activity to food cues supporting the conclusion that obese children try to avoid to engage in processing of food cues, rather than showing increased appetitive motivation.