Interictal thalamocortical network configuration is associated with susceptibility to seizure-related impaired consciousness in focal epilepsy.
Source: PubMed, NCBI / U.S. National Library of Medicine
Focal seizures with impaired consciousness (FIC) and focal to bilateral tonic-clonic seizures (FBTCS) impose substantial medical and psychosocial burden. Although the centromedian nucleus (CMN) is a promising neuromodulation target, its role in seizure-related impairment of consciousness remains unclear. We therefore used CMN-SEEG recordings to examine interictal thalamocortical network features associated with impaired consciousness. We analyzed awake interictal epochs without epileptiform discharges from 14 children undergoing CMN-SEEG. Thalamocortical interactions among the CMN, seizure-onset zone (SOZ), and non-SOZ cortex were compared according to FIC and FBTCS phenotypes. Power spectral density was parameterized into periodic and aperiodic components. To ensure physiologically meaningful connectivity estimates, phase synchronization index (PSI) was calculated only for electrode pairs exhibiting concurrent oscillatory peaks within each frequency band, as identified using spectral parameterization. PSI was then used to quantify functional connectivity between CMN-SOZ and CMN-non-SOZ networks across canonical frequency bands. FBTCS was associated with significantly lower aperiodic offset in both the SOZ and CMN. PSI analysis revealed significant interactions between network type (CMN-SOZ vs. CMN-non-SOZ) and FIC status in the theta, alpha, and beta bands, as well as a significant interaction with FBTCS status in the beta band. Interictal thalamocortical network organizatio
Abstract
Focal seizures with impaired consciousness (FIC) and focal to bilateral tonic-clonic seizures (FBTCS) impose substantial medical and psychosocial burden. Although the centromedian nucleus (CMN) is a promising neuromodulation target, its role in seizure-related impairment of consciousness remains unclear. We therefore used CMN-SEEG recordings to examine interictal thalamocortical network features associated with impaired consciousness. We analyzed awake interictal epochs without epileptiform discharges from 14 children undergoing CMN-SEEG. Thalamocortical interactions among the CMN, seizure-onset zone (SOZ), and non-SOZ cortex were compared according to FIC and FBTCS phenotypes. Power spectral density was parameterized into periodic and aperiodic components. To ensure physiologically meaningful connectivity estimates, phase synchronization index (PSI) was calculated only for electrode pairs exhibiting concurrent oscillatory peaks within each frequency band, as identified using spectral parameterization. PSI was then used to quantify functional connectivity between CMN-SOZ and CMN-non-SOZ networks across canonical frequency bands. FBTCS was associated with significantly lower aperiodic offset in both the SOZ and CMN. PSI analysis revealed significant interactions between network type (CMN-SOZ vs. CMN-non-SOZ) and FIC status in the theta, alpha, and beta bands, as well as a significant interaction with FBTCS status in the beta band. Interictal thalamocortical network organization involving the CMN is associated with susceptibility to seizure-related impaired consciousness. Band-specific differences in the relative configuration of CMN-SOZ and CMN-non-SOZ synchronization, together with reduced aperiodic offset in FBTCS, may reflect interictal network states related to vulnerability or resilience to impaired consciousness during focal seizures.