Appetitive Conditioning in Anorexia Nervosa

Anorexia nervosa (AN) is characterized by a reduced drive to pursue rewarding experiences and stimuli. Food consumption - which is almost universally experienced as pleasurable - is not described as rewarding by those with AN. This is thought to be underpinned by abnormalities around reward learning. However, the most fundamental question relating to reward in AN - whether those with AN may learn positive associations - remains unaddressed. In this study, the investigators will identify the patterns of how those with AN acquire positive associations, how they diminish, and their relationships to physiology (heart rate and pupil responses) and brain activation. In assessing the robustness of this learning, the investigators will investigate the extent to which this association is reactivated after 24 hours, and the extent to which a memory prompt will help reinstate this previously learned positive association. This project will allow for important advances in our understanding of the neurobiology of AN. The investigators will first identify if, and how, those with AN come to learn positive associations to cues, and secondly, the extent to which learned positive associations remain over time. Moreover, the investigators will use machine learning to ascertain whether reward learning can be predicted by physiological and neural biomarkers.