Altered Functional Organization within and between Resting-State Networks in Chronic Subcortical Infarction

Abstract

This study aimed to investigate the changes in functional connectivity (FC) within each resting-state network (RSN) and between RSNs in subcortical stroke patients who were well recovered in global motor function. Eleven meaningful RSNs were identified via functional magnetic resonance imaging data from 25 subcortical stroke patients and 22 normal controls using independent component analysis. Compared with normal controls, stroke patients exhibited increased intranetwork FC in the sensorimotor (SMN), visual (VN), auditory (AN), dorsal attention (DAN), and default mode (DMN) networks; they also exhibited decreased intranetwork FC in the frontoparietal network (FPN) and anterior DMN. Stroke patients displayed a shift from no FC in controls to negative internetwork FC between the VN and AN as well as between the VN and SMN. Stroke patients also exhibited weakened positive (anterior and posterior DMN; posterior DMN and right FPN) or negative (AN and right FPN; posterior DMN and dorsal SMN) internetwork FC when compared with normal controls. We suggest that subcortical stroke may induce connectivity changes in multiple functional networks, affecting not only the intranetwork FC within RSNs but also the internetwork FC between these RSNs.

Gray matter volume changes in chronic subcortical stroke: A cross-sectional study

“…Similarly, the intergroup differences in intra- and inter-network function connectivity are found to be evidently different between the left- and right-sided stroke patients (Wang et al, 2014). The exact neural mechanisms underlying the lesion-side effect on GMV following subcortical stroke are far from clear, however, several possibilities may be related to this effect.…”

“…However, most prior neuroimaging studies on stroke recovery have not taken the issue into consideration. They either only focus on one side of lesions (Fan et al, 2013, Xing et al, 2016) or flipped the imaging data from one side to another along the midline (Abela et al, 2015, Wang et al, 2014, Zhang et al, 2014). In other words, it is remains unclear whether brain structural and functional alterations are different in subcortical stroke patients with lesions in the left and right hemispheres, which may help to identify the common and specific changes following the left and right hemispheric subcortical damage.…”

Integrity of normal-appearing white matter and functional outcomes after acute ischemic stroke

“…17 Therefore, it is reasonable to assume that DTI-based anisotropy metrics of NAWM provide insights into WM composition and, as a result, are informative of functional connectivity and overall cognitive performance. 7,27,[29][30][31] Thus, it seems intuitive that WM integrity would influence poststroke recovery. 3,4,[32][33][34][35] The exact mechanisms by which prestroke WM integrity might influence poststroke functional recovery are yet to be determined; however, data that underscore the role of structural connectivity in functional performance in general populations point in the direction of potential underlying pathology.…”

Structural and Resting-State Brain Connectivity of Motor Networks After Stroke

“…A non-hypothesis-driven independent component analysis decomposition of RSNs in patients with chronic stroke 48 found elevated intranetwork connectivity in different sensory, motor, and default mode networks compared with controls, but connectivity was decreased within associative frontoparietal networks and between networks. These findings partly suggest that RSNs reorganization in the chronic stage involves higher integration within networks than across.…”