Evidence for a specific regional association between lateral orbitofrontal cortex morphometry and increased appetite in major depression

Abstract

Increased appetite and body weight are core features of atypical depression. While previous research has consistently highlighted the presence of distinct immunometabolic profiles in atypical depression, little is still known about the neural correlates of atypical symptoms in major depression. Even though obesity and increased body-mass index have frequently been associated with prefrontal brain structural alterations first and foremost in the orbitofrontal cortex (OFC) in healthy and depressed subjects, it is unclear if conceptually related atypical depressive symptoms are associated with similar neural signatures. Here we aimed to investigate associations between appetite and weight change in major depression and OFC morphometry using a multimodal structural neuroimaging approach. We found that increased appetite was associated with significantly lower cortical thickness and lower gray matter density specifically in the right lateral OFC. Further, Bayesian model comparison showed that appetite change was a more informative predictor for changes in cortical thickness and gray matter density compared to body mass index. No conclusive association between appetite change and white matter tracts connected to the right lateral OFC was found. Our findings highlight the relevance of the right lateral OFC for future investigation of the neurobiological underpinnings of the atypical depressive symptom dimensions appetite and weight gain.