Depression and anxiety symptoms are associated to disruption of default mode network in subacute ischemic stroke

Depression and anxiety symptoms are common after stroke and associated to reduction in quality of life and poor physical and social outcomes. The Default Mode Network (DMN) plays an important role in the emotional processing. We investigated whether these symptoms are associated to a disruption of DMN functional connectivity in the first month after stroke. Thirty-four subacute ischemic stroke patients were submitted to: 1) behavioral assessment through Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Structured Clinical Interview for DSM Disorders; 2) neuropsychological assessment using Mini Mental State Examination and Montreal Cognitive Assessment; 3) resting state functional magnetic resonance imaging acquisition using a 3 T scanner (Philips Achieva). Patients with depression and/or anxiety symptoms showed an increased DMN functional connectivity in left inferior parietal gyrus and left basal nuclei, when compared to stroke controls. Specific correlation between BDI/BAI scores and DMN functional connectivity indicated that depression symptoms are correlated with increased functional connectivity in left inferior parietal gyrus, while anxiety symptoms are correlated with increased functional connectivity in cerebellum, brainstem and right middle frontal gyrus. Our study provides new insights into the underlying mechanisms of post stroke depression and anxiety, suggesting an alternate explanation other than regional structural damage following ischemic event, that these psychiatric symptoms are related to brain network dysfunction.