Abstract
ObjectiveThis study intends to track whole-brain functional connectivity strength (FCS) changes and the lateralization index (LI) in left basal ganglia (BG) ischemic stroke patients.MethodsTwenty-five patients (N = 25; aged 52.73 ± 10.51 years) with five visits at <7, 14, 30, 90, and 180 days and 26 healthy controls (HCs; N = 26; 51.84 ± 8.06 years) were examined with resting-state functional magnetic resonance imaging (rs-fMRI) and motor function testing. FCS and LI were calculated through constructing the voxel-based brain functional network. One-way analysis of covariance (ANOVA) was first performed to obtain longitudinal FCS and LI changes in patients among the five visits (Bonferroni corrected, P < 0.05). Then, pairwise comparisons of FCS and LI were obtained during the five visits, and the two-sample t test was used to examine between-group differences in FCS [family-wise error (FWE) corrected, P < 0.05] and LI. Correlations between connectivity metrics (FCS and LI) and motor function were further assessed.ResultsCompared to HCs, decreased FCS in the patients localized in the calcarine and inferior occipital gyrus (IOG), while increased FCS gathered in the middle prefrontal cortex (MPFC), middle frontal gyrus, and insula (P < 0.05). The LI and FCS of patients first decreased and then increased, which showed significant differences compared with HCs (P < 0.05) and demonstrated a transition at the 30-day visit. Additionally, LI at the third visit was significantly different from those at the other visits (P < 0.05). No significant longitudinal correlations were observed between motor function and FCS or LI (P > 0.05).ConclusionFocal ischemic stroke in the left BG leads to extensive alterations in the FCS. Strong plasticity in the functional networks could be reorganized in different temporal dynamics to facilitate motor recovery after BG stroke, contribute to diagnosing the disease course, and estimate the intervention treatment.
Highlights
Cerebral stroke is a major cause of mortality and long-term disability
Major functional connectivity strength (FCS) decreases gathered in the left CAL and right inferior occipital gyrus (IOG), and FCS increases more likely located in the right middle prefrontal cortex (MPFC), bilateral MFG, and right INS. (b) Comparing the healthy controls (HCs), LI lost the left hemisphere dominance in patients, and LI changes at the 30-day visit were significant. (c) Transition of FCS and LI changes occurred in the patients with five visits, and the turning point occurred approximately 30 days after onset, which served as a predictive biomarker for the development of basal ganglia (BG) stroke
In the left BG stroke patients, we found that decreased FCS localized in the CAL and IOG
Summary
Cerebral stroke is a major cause of mortality and long-term disability. More than 80% of strokes stem from ischemic damage to the brain due to the acute reduction of the blood supply (Kessner et al, 2019). Functional connectivity strength (FCS), a graph theory-based analysis method can explore nodal weighted centrality and reflect its FC within the whole brain network (Gao et al, 2017; Zhang et al, 2020). This measurement indirectly reflects the position and importance of the node or brain regions in the whole-brain networks, without a priori defined seed (Wang L. et al, 2014). Combination of rs-fMRI and lateralization may provide reliable metrics and has been successfully used in brain disorders (Rosazza et al, 2013)
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