Altered late semantic processing of food stimuli in female anorexia nervosa and atypical anorexia nervosa patients

Introduction Anorexia Nervosa (AN) patients exhibit cognitive and neural disturbances during food processing, yet underlying mechanisms remain unclear. Our study investigated whether AN and Atypical AN (AAN) patients show altered neural, cognitive, and behavioral responses to high and low-calorie food stimuli, and whether these effects appear largely food-specific. Methods Seventeen AN/AAN, 17 HCs, and 17 overweight/obese females viewed high and low-calorie food stimuli, rated palatability (yes/no), and completed an emotional picture viewing task (IAPS) while high-density EEG was recorded. Results Palatability ratings did not differ significantly among groups; however, exploratory analyses suggested that patients with the restricting subtype (AN-R; n  = 6) rated high-calorie foods as less palatable than low-calorie foods compared to other groups. EEG findings revealed significant but modest group-specific modulation (N400; 388–418 ms; p  = 0.049; Cluster size = 97 voxels; Peak statistic X  = 9.78): HCs showed enhanced responses to high-calorie food, whereas AN/AAN and overweight/obese participants showed greater responses to low-calorie food. Source localization implicated the right fusiform gyrus and inferior-medial temporal cortices. No comparable effects occurred during the IAPS task. Conclusion AN/AAN individuals exhibit disrupted calorie-dependent semantic processing in right inferior temporal regions, indicating altered food evaluation. These findings provide a neural basis for restrictive eating in AN/AAN, highlighting the role of semantic processing in disorder-specific food disturbances.