Topological reorganization of the default mode network in patients with poststroke depressive symptoms: A resting-state fMRI study
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AbstractObjective
This study mapped the topological configuration of the default mode network (DMN) in patients with depressive symptoms after acute ischemic stroke.

Methods
The study sample comprised 63 patients: 36 with poststroke depressive symptoms (PSD) and 37 without PSD matched according to age, gender and the severity of stroke. PSD was defined by a cutoff of ≥ 7 on the 15-item Geriatric Depression Scale (GDS). Resting-state functional magnetic resonance imaging (fMRI) was used to examine functional connectivity (FC) to reconstruct the DMN. Network based statistics estimated the FC differences of the DMN between the PSD and non-PSD groups. Graph theoretical approaches were used to characterize the topological properties of this network.

Results
The study sample mainly comprised patients with mild to moderate stroke. A widespread hyper-connected configuration of the functional DMN was characterized in PSD group. The orbital frontal, dorsolateral prefrontal, dorsal medial prefrontal and, ventromedial prefrontal corticis, the middle temporal gyrus and the inferior parietal lobule were the functional hubs related to PSD. The nodal topology in inferior parietal lobule and superior frontal gyrus, overlapping with dorsal medial prefrontal and, ventromedial prefrontal cortices, tended to be functionally integrated in patients with PSD. After False Discovery Rate correction, no significant difference between the PSD and non-PSD groups was found with respect to the global and nodal metrics of the DMN. However, the correlations between these altered network metrics and severity of PSD were lacking.

Limitations
The diagnosis of PSD was based on the GDS score rather than established with a structured clinical interview.

Conclusions
The DMN in PSD was functionally integrated and more specialized in some core hubs such as the inferior parietal lobule and dorsal prefrontal cortex. The configuration of the subnetwork like DMN may be more essential in the pathogenesis of PSD than single stroke lesions.
Acceptance Date08/09/2019
All Author(s) ListLiang Y, Yao YC, Zhao L, Shi L, Chen YK, Mok VC, Ungvari GS, Chu WC, Tang WK
Journal nameJournal of Affective Disorders
Year2020
Month1
Volume Number260
Pages557 - 568
ISSN0165-0327
LanguagesEnglish-United States
KeywordsDefault mode network; Functional magnetic resonance imaging; Graph theoretical analysis; Poststroke depressive symptoms; Stroke

Last updated on 2020-01-04 at 23:48