White-matter disconnection shapes distributed cortical spectral dynamics after stroke

Focal brain lesions are thought to induce sleep-like slow-wave activity in perilesional cortex through altered excitation-inhibition balance and structural disconnection, but whether these dynamics extend to remote yet structurally intact regions remain unclear. Here we combined source-reconstructed high-density EEG (128 channels) with structural disconnection mapping in 49 acute stroke patients and 20 age-matched controls. Cortical regions were classified as perilesional, structurally disconnected, or non-disconnected using individual lesion masks registered to normative white-matter atlases. Perilesional cortex showed increased delta and theta power and reduced beta power relative to controls. Critically, structurally disconnected regions exhibited electrophysiological changes comparable to perilesional cortex, including enhanced low-frequency activity and steeper aperiodic spectral slopes. These alterations correlated with neurological severity and multidomain behavioral impairment. Our findings demonstrate that post-stroke slow-wave activity propagates along structural disconnection pathways, providing direct electrophysiological evidence for connectional diaschisis and identifying distributed network targets for physiology-guided neuromodulation.