Cognition-related brain networks underpin the symptoms of unipolar depression: Evidence from a systematic review

• Systematic review of cognition-related networks and symptoms of unipolar depression.
• Autobiographic memory network (AMN) overactive; linked to rumination, brooding.
• Cognitive control network (CCN) anticorrelated with AMN and therefore underactive.
• CCN abnormality linked to poor concentration and cognitive distortion in depression.
• Downstream effects include dysregulation of affective and vegetative networks.

This systematic review sources the latest neuroimaging evidence for the role of cognition-related brain networks in depression, and relates their abnormal functioning to symptoms of the disorder. Using theoretically informed and rigorous inclusion criteria, we integrate findings from 59 functional neuroimaging studies of adults with unipolar depression using a narrative approach. Results demonstrate that two distinct neurocognitive networks, the autobiographic memory network (AMN) and the cognitive control network (CCN), are central to the symptomatology of depression. Specifically, hyperactivity of the introspective AMN is linked to pathological brooding, self-blame, rumination. Anticorrelated under-engagement of the CCN is associated with indecisiveness, negative automatic thoughts, poor concentration, distorted cognitive processing. Downstream effects of this imbalance include reduced regulation of networks linked to the vegetative and affective symptoms of depression. The configurations of these networks can change between individuals and over time, plausibly accounting for both the variable presentation of depressive disorders and their fluctuating course. Framing depression as a disorder of neurocognitive networks directly links neurobiology to psychiatric practice, aiding researchers and clinicians alike.