Abstract
Functional connectivity maps using resting-state functional magnetic resonance imaging (rs-fMRI) can closely resemble task fMRI activation patterns, suggesting that resting-state brain activity may predict task-evoked activation or behavioral performance. However, this conclusion was mostly drawn upon a healthy population. It remains unclear whether the predictive ability of resting-state brain activity for task-evoked activation would change under different pathological conditions. This study investigated dynamic changes of coupling between patterns of resting-state functional connectivity (RSFC) and motion-related activation in different stages of cerebral stroke. Twenty stroke patients with hand motor function impairment were involved. rs-fMRI and hand motion-related fMRI data were acquired in the acute, subacute, and early chronic stages of cerebral stroke on a 3-T magnetic resonance (MR) scanner. Sixteen healthy participants were enrolled as controls. For each subject, an activation map of the affected hand was first created using general linear model analysis on task fMRI data, and then an RSFC map was determined by seeding at the peak region of hand motion activation during the intact hand task. We then measured the extent of coupling between the RSFC maps and motion-related activation maps. Dynamic changes of the coupling between the two fMRI maps were estimated using one-way repeated measures analysis of variance across the three stages. Moreover, imaging parameters were correlated with motor performances. Data analysis showed that there were different coupling patterns between motion-related activation and RSFC maps associating with the affected motor regions during the acute, subacute, and early chronic stages of stroke. Coupling strengths increased as the recovery from stroke progressed. Coupling strengths were correlated with hand motion performance in the acute stage, while coupling recovery was negatively correlated with the recovery outcome of hand motion performance in the early chronic stages. Couplings between RSFC and motion-related activation were dynamically changed with stroke progression, which suggested changes in the prediction of resting-state brain activity for task-evoked brain activity in different pathological states. The changes in coupling strength between these two types of brain activity implicate a reparative mechanism of brain injury and may represent a biomarker for predicting motor recovery in cerebral stroke.
Highlights
Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging, as a non-invasive imaging technique, has become an effective tool for investigating the human brain, both in a clinical context and a research context
Our main novel findings were as follows: [1] compared with healthy controls, stroke patients showed reduced motion-related activation and coupling strength during the acute and subacute stages; [2] compared with the acute stage, motion-related activation and resting-state functional connectivity (RSFC) strength significantly increased in the ipsilesional sensorimotor cortex during the early chronic stage; and [3] coupling strength between motion-related activation and RSFC in the ipsilesional sensorimotor cortex was significantly increased following motor function recovery from the acute stage to the early chronic stage in stroke patients with motor impairment
These findings indicated that the coupling relationship between task-based functional magnetic resonance imaging (fMRI) and resting-state fMRI (rs-fMRI) in stroke patients was influenced by different stages of pathological progression
Summary
Blood oxygenation level-dependent (BOLD) functional magnetic resonance imaging (fMRI), as a non-invasive imaging technique, has become an effective tool for investigating the human brain, both in a clinical context and a research context. The pattern of resting-state spontaneous brain activity is regarded as a potential predictor for brain activation [16,17,18], and an individual’s task performance or behavior [19]. These interpretations were mostly based on studies involving a healthy population. No previous studies have used fMRI to investigate the changing patterns of coupling between these two types of activity under different pathological conditions
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