Depression Circuit Adaptation In Post-stroke Depression

Stroke is an acute cerebrovascular disease characterized by focal neurological impairment,with high incidence,high disability rate and high mortality.In addition to sensory and motor dysfunction,stroke can also cause emotional disorders.Post-stroke depression(PSD)is one of the most frequent psychiatric disorders after stroke.The patients with PSD are often associated with lower quality of life,poor functional prognosis,and higher mortality.Therefore,it is very important to study and explore the brain mechanism of PSD.In recent years,rs-f MRI has become a common method for examining brain function.Its advantages such as no unnecessary cooperation of subjects and simple operation provide great convenience for the diagnosis and research of brain diseases,so it is widely used in the brain function research of stroke and PSD.Functional connectivity(FC)is a commonly used index to study the abnormal brain mechanism of PSD.Most previous studies have identified regions of interest to analyze dysfunctional brain regions based on primary depression outcomes,while ignoring the impact of attention outcomes.However,a recent study pointed out that lesion locations of PSD mapped to a depression circuit which centered by the left dorsolateral prefrontal cortex(DLPFC).Repetitive transcranial magnetic stimulation(r TMS)targets in the clinical treatment of PSD are also in this depression ring.However,it remains unknown whether the compensatory adaptations that may occur in this depression circuit due to the lesions in PSD.Furthermore,it is unclear whether there are ideal therapeutic targets in this depression circuit.Using rs-f MRI,we aim to investigate the PSD-specific alterations of connectivity within the depression circuit,and further explore the potentially optimum r TMS treatment target for PSD.In current study,rs-f MRI data were collected from 82 non-depressed stroke patients(Stroke),39 PSD patients and 74 healthy controls(HC).We tested the existence of depression circuit,examined PSD-related alterations of DLPFC-seeded connectivity and their associations with depression severity,and analyzed the connectivity between each r TMS target and DLPFC to find the best treatment target for PSD.We found that:(1)based on brain lesions,depression circuit centered left DLPFC have been found in PSD;(2)in comparison to both Stroke and HC groups,PSD exhibited increased connectivity with DLPFC in bilateral lingual gyrus,contralesional superior frontal gyrus(SFG),precuneus(PCUN),and middle frontal gyrus(MFG);(3)the connectivity between DLPFC and the contralesional LING positively correlated with depression severity;(4)the r TMS target in center of MFG showed largest betweengroup difference in connectivity with DLPFC,and also reported the highest predicted clinical efficacy.Collectively,these findings demonstrated the PSD underwent specific alterations in depression circuit,which may help to establish objective imaging markers for early diagnosis and interventions of the disease.