Prefrontal Hierarchical Control of Corticomuscular Coherence in Stroke

Stroke recovery involves reorganization of large-scale brain networks, yet most neurophysiological biomarkers assess either motor or cognitive function in isolation. To address this limitation, we introduce phase-modulated corticomuscular coherence (pmCMC), a novel metric that quantifies how prefrontal delta-phase activity modulates beta-band corticomuscular coherence between the primary motor cortex and peripheral muscle. This approach integrates cross-frequency and corticomuscular coupling, offering a dynamic index of cognitive-motor interaction. We applied pmCMC to a cohort of individuals with hemiparetic stroke who performed a precision grip task during high-density EEG and EMG recording at admission and discharge from an inpatient rehabilitation facility. Our findings reveal that pmCMC increases across rehabilitation and positively relates to corticostriatal but not corticospinal tract injury. Additionally, higher pmCMC at admission was positively associated with greater gains in motor coordination, functional independence, and cognitive status. These results position pmCMC as hybrid neurophysiological measure of cognitive-motor integration relevant to post-stroke recovery and encourages further investigation of its prognostic utility, causal mechanisms, and applicability across diverse motor tasks and clinical populations.