Medial prefrontal default-mode hypoactivity affecting trait physical anhedonia in schizophrenia

Anhedonia, as a deficit symptom, may be associated with default-mode hypofrontality in schizophrenia. To explore whether trait anhedonia in schizophrenia pertains to altered hypofrontal resting state brain function, resting state metabolic activities were compared and correlated with the Physical and Social Anhedonia Scale scores in 29 patients with schizophrenia and 21 healthy controls using ¹⁸F-fluorodeoxyglucose positron emission tomography (¹⁸F-FDG-PET). In patients with schizophrenia, Physical Anhedonia Scale scores showed a trend-level negative correlation with the hypoactive dorsomedial prefrontal metabolism while Positive and Negative Symptom Scale (PANSS) negative subscale scores positively correlated with hyperactive cerebellar metabolism. Voxelwise correlation analysis showed physical anhedonia correlates in resting state activities of the supplementary motor area, ventromedial and dorsolateral prefrontal cortex, insular gyrus, and the precuneus in patients with schizophrenia while no frontal metabolic correlates were found in healthy controls. The hypoactive dorsomedial prefrontal metabolism correlated with physical anhedonia-correlated resting state regional activities. These findings provide further evidence for the relation of functional hypofrontality to the deficit syndrome and possible involvement of the functional imbalance in the cortico-cerebellar-thalamic-cortical circuit in the resting state brain function of schizophrenia.