Mapping neural mechanisms of appetitive behavior

Tasty food is both pleasure and pain. Hedonic indulgence conflicts with a healthy eating and healthy weight goal. Tasty food cues activate behavioural and neural approach tendencies that can undercut rational dietary decision making. Yet, it has proven difficult to measure these automatic approach tendencies due to methodological reasons. As a result, treatment development is slowed and weight reduction programs often fail due to cravings and binge eating. Among a range of behavioural measures that putatively index automatic responses to appetitive stimuli, approachavoidance tests (AAT) have more recently gained considerable attention. Derived from the anxiety literature, the AAT has now been applied to appetitive stimuli including drugs, alcohol and snack foods. In the alcohol domain, trainings based on the AAT have shown clinical utility. Yet, in the food domain, results are more mixed. The present proposal builds on a previous behavioural paper by our group showing that AAT biases in the form of faster pull than push movements with a joystick in response to images of foodsonly emerge when individuals attend to the images and not when they attend to an irrelevant image feature. Thus, attention to the image might be necessary for a full reward response to unfold, which, in consequence, might trigger approach-related motor response systems. Mechanisms of such attentional modulations might be uncovered through functional magnetic resonance imaging (fMRI): when attention is guided to image content through respective instructions, reward system activity might become evident and might show connectivity with motor system activity, thereby mediating behavioural approach biases. There is a striking lack of neural data on processes underlying AAT effects and, thus, no mechanism- oriented approach bias modification line could emerge that would provide a tool to mitigate the persistent cravings and snacking habits and their deleterious effects on nutritional health. The present proposal thus develops a neural network model of food-related AAT effects and tests it with state of the art fMRI analysis and connectivity methodology.

Palatable foods activate automatic approach tendencies, which we have investigated in this project using reaction time measures. The studies indicate that unhealthy eating behaviors are partially attributable to such automatic approach tendencies generated in the cognitive-affective system. Thus, additional self-regulation is needed in order to develop healthful eating habits.