Major Depressive Disorder Shows Frequency-specific Abnormal Functional Connectivity Patterns Associated with Anhedonia

Anhedonia is a core feature of major depression disorder (MDD), is associated with the dysfunction of the dopamine system. Here, we aimed to examine how resting-state functional connectivity (FC) within the dopamine system in MDD patients is related to anhedonia and whether this relationship relies on specific frequency bands (slow 4: 0.027-0.073 Hz and slow 5: 0.01-0.027 Hz). The regional connectivity strength and FC were evaluated. Our results revealed decreased connectivity strength in MDD in the posterior cingulate cortex and hippocampus at slow 4 and in the anterior insula and hippocampus at slow 5. Of note, increased FC in the mesocorticolimbic system was found in MDD only at slow 5. Furthermore, the altered connectivity at slow 5 contributed to predicting anhedonia symptom and depression severity. These findings suggest that dopamine system functional connectivity remains a prime target for understanding the anhedonia of MDD.