Cortical Activation and Connectivity of Frontoparietal Lobe During Wrist Movements in Stroke Patients: Insights from Functional Near-Infrared Spectroscopy

WEIWEI LU^1,2XUNLUN JIN³Guanghua Liu³Liang Zhou^4*JING CHEN^3*TAO WU^1,4*

• ¹Tongji University School of Medicine, Shanghai, China
• ²Shanghai Geriatric Medical Center, Shanghai, China
• ³Zhongshan Hospital Fudan University, Shanghai, China
• ⁴Shanghai University of Medicine and Health Sciences, Shanghai, China

Objective: The combined use of multiple rehabilitation interventions for stroke in real-world settings makes it difficult to isolate and observe the specific effects of each training method on cortical activity. This study aimed to investigate immediate cortical responses in the frontoparietal lobe to commonly applied wrist extension tasks—active movement, assisted movement, and motor imagery—in patients with subcortical ischemic stroke. Methods: Fifteen patients with subcortical ischemic stroke were recruited for this experiment. The functional near-infrared spectroscopy (fNIRS) with 53 channels collected the change of Oxyhemoglobin concentration (HBO) on the frontoparietal lobe, when patients conducted the three tasks of wrist extension, including active movement, assisted movement, and motor imagery. The sampling rate was 20 Hz. Generalized linear model analysis of HBO was used to estimate β values of each channel. Single-sample t-test of the β value was employed across the 53 fNIRS channels, evaluating if each task activated the frontoparietal lobe. Pearson correlation analysis was employed to analyze functional connectivity (FC) between regions of interest (ROIs) during the three tasks. Results: The active wrist extension task exhibited significant activation in the Supramarginal Gyrus - Wernicke's Area, Somatosensory Cortex (S1), Premotor and Supplementary Motor Cortex (PreM & SMC), Primary Motor Cortex (M1), Frontal Eye Field (FEF). The assisted wrist extension task demonstrated significant activation in the Supramarginal Gyrus - Wernicke's Area, S1, PreM & SMC. The motor imagery task showed significant activation in the Supramarginal Gyrus - Wernicke's Area, S1, FEF, PreM & SMC. During active movement, contralesional PreM & SMC exhibited strong correlations with both bilateral M1. In the assisted movement task, contralesional PreM & SMC were highly correlated with contralesional M1, ipsilesional M1, and ipsilesional PreM & SMC. Furthermore, contralesional S1 demonstrated a strong correlation with ipsilesional PreM & SMC. During motor imagery, contralesional PreM & SMC maintained significant correlations with bilateral M1. Conclusion: Active, assisted movement and motor imagery of wrist extension significantly enhanced activation in the frontoparietal region of ischemic stroke patients. FC between ROIs suggested that ipsilesional M1 and contralesional PreM & SMC would be key therapeutic targets for motor recovery.