FOCAL RADIOFREQUENCY THERMOCOAGULATION DISRUPTION OF HEMODYNAMICS BEYOND THE LESION CORE: INTER AND INTRAHEMISPHERIC EFFECTS

Hemodynamic coupling between cerebral blood flow (CBF), oxygenated (HbO), and deoxygenated hemoglobin (HbR) provides a window into the cortical dynamics linking neuronal activity to oxygen demand, delivery, extraction, and consumption. Characterizing this relationship is essential for interpreting hemodynamic signals—particularly blood oxygenation level dependent (BOLD) response—whose relationship with neuronal activity remains incompletely understood, especially under pathological conditions (Devor et al., 2003). We investigated CBF-HbO and CBF-HbR cortical brain-wide network coupling before and after focal lesions induced by radiofrequency thermocoagulation (RFTC) in the anesthetized mouse. RFTC is used in neurosurgery to silence pathological neuronal discharges. We leveraged RFTC (150 µA, DC=30s) as a network disruption model to quantify changes in hemodynamic coupling. Hemodynamics were acquired using simultaneous Laser Speckle Flowmetry and Optical Intrinsic Signal Imaging, enabling non-contact, high spatial resolution, temporally resolved (50 Hz), wide-field (~8x8 mm2) mapping of perfusion and oxygenation across the cortex. At baseline, CBF is coupled to HbO (Lin and Powers, 2018). In perilesional cortex, 2h post-lesion we observed reduced CBF, decreased HbO, and increased HbR, consistent with impaired oxygen delivery relative to metabolic demand. These effects extended beyond the lesion: in distant (~5 mm) ipsilesional regions, we observed modest increases in CBF accompanied by elevated HbR, suggesting a mismatch between flow and oxygenation. Overall, this 1-mm lesion produced hemodynamic alterations that propagated beyond the perilesional zone, consistent with large-scale network disruption and with diaschisis, whereby damage to one node perturbs function in connected, remote regions. Funded by European Union (ERC, NEMESIS-101071900).