Abstract
Background and purposeCognitive impairment is a common consequence of stroke, and the rewiring of the surviving brain circuits might contribute to cognitive recovery. Studies investigating how the functional connectivity of networks change across time and whether their remapping relates to cognitive recovery in stroke patients are scarce. We aimed to investigate whether resting-state functional connectivity was associated with cognitive performance in stroke patients and if any alterations in these networks were correlated with cognitive recovery. MethodsUsing an fMRI ROI-ROI approach, we compared the ipsilesional, contralesional and interhemispheric functional connectivity of three resting-state networks involved in cognition – the Default Mode (DMN), Salience (SN) and Central Executive Networks (CEN), in subacute ischemic stroke patients (time 1, n = 37, stroke onset: 24.32 ± 7.44 days, NIHSS: 2.66 ± 3.45) with cognitively healthy controls (n = 20). Patients were reassessed six months after the stroke event (time 2, n = 20, stroke onset: 182.05 ± 8.17 days) to verify the subsequent reorganization of functional connections and whether such reorganization was associated with cognitive recovery. ResultsAt time 1, patients had weaker interhemispheric connectivity in the DMN than controls; better cognitive performance at time 1 was associated with stronger interhemispheric and ipsilesional DMN connectivity, and weaker contralesional SN connectivity. At time 2, there were no changes in functional connectivity in stroke patients, compared to time 1. Better cognitive recovery measured at time 2 (time 2 – time 1) was associated with stronger functional connectivity in the DMN, and weaker interhemispheric subacute connectivity in the SN, both from time 1. ConclusionsStroke disrupts the functional connectivity of the DMN, not only at the lesioned hemisphere but also between hemispheres. Six months after the stroke event, we could not detect the remapping of networks. Cognitive recovery was associated with the connectivity of both the DMN and SN of time 1. Our findings may be helpful for facilitating further understanding of the potential mechanisms underlying post-stroke cognitive performance.
Highlights
Worldwide, cerebrovascular accidents are the second lead ing cause of death and the third leading cause of disability (WHO, 2012)
Our goals were two-fold: to measure the integrity of three networks involved in cognition – the Default Mode Network (DMN), the Central Executive Networks (CEN) and the SN (Sridharan et al, 2008), and to ascertain whether possible network disruptions were related to cognitive performance in subacute stroke patients
As we found a significant cognitive recovery at time 2, we analyzed whether changes in Montreal Cognitive Assessment (MoCA) scores (ΔMoCA) could be related to changes in functional connectivity (ΔFC), or functional connectivity at time 1 (FCtime1)
Summary
Cerebrovascular accidents (stroke) are the second lead ing cause of death and the third leading cause of disability (WHO, 2012). For example, has shown acute (Jiang et al, 2018) and choric disruptions (Dacosta-Aguayo et al, 2015; Tuladhar et al, 2013) in the Default Mode Network (DMN) and other resting-state networks (Wang et al, 2014) after a stroke event In this context, the rewiring of the surviving brain circuits can contribute and predict cognitive recovery after stroke (Carter et al, 2010, 2012; Dacosta-Aguayo et al, 2014b; Ding et al, 2014; Puig et al, 2018; Siegel et al, 2016). Methods: Using an fMRI ROI-ROI approach, we compared the ipsilesional, contralesional and interhemispheric functional connectivity of three resting-state networks involved in cognition – the Default Mode (DMN), Salience (SN) and Central Executive Networks (CEN), in subacute ischemic stroke patients (time 1, n = 37, stroke onset: 24.32 ± 7.44 days, NIHSS: 2.66 ± 3.45) with cognitively healthy controls (n = 20). Our findings may be helpful for facilitating further understanding of the potential mechanisms underlying post-stroke cognitive performance
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