Neural and behavioral signatures of food reward processing in co-occurring depression and body fat-defined obesity: Evidence from behavioral and fMRI tasks

Objective Depression and obesity frequently co-occur and are associated with greater functional impairment, yet food-reward processing in their co-occurrence remains poorly understood. This study examined behavioral and neural signatures of food-reward processing in adults classified by depressive symptoms and BFP-defined obesity. Methods One hundred and one adults completed the PHQ-9, BIA-based body-composition assessment, standardized food-image ratings, and an fMRI FID task separating reward anticipation from outcome feedback. Participants were categorized as HC, OW/OB, DS, or OW/OB-DS. The fMRI analyses included 91 participants after motion quality control. Results No significant between-group differences were observed in food-image rating indices or FID target-response RTs. Whole-brain analyses showed Group effects centered in bilateral fusiform regions, with additional involvement of rAIns and mCC across anticipation and feedback. DCM showed stronger lFusG-to-rAIns modulation in OW/OB than HC and in OW/OB-DS than OW/OB during food reward anticipation. During food reward feedback, OW/OB-DS showed more negative mCC-to-rdlPFC modulation than DS and OW/OB. Conclusions In this symptom-defined, nonclinical sample, the findings identify phase-specific group differences in visual-salience and cingulate-prefrontal effective connectivity during food-reward processing.