Dynamic evolution of the anterior cingulate‐insula network during seizures

Abstract

ObjectivesIn physiological situations, the anterior cingulate cortex (ACC) and anterior insular cortex (AIC) are prone to coactivation. The functional connectivity and interaction between ACC and AIC in the context of epilepsy remain unclear. This study aimed to investigate the dynamic coupling between these two brain regions during seizures.MethodsPatients who underwent stereoelectroencephalography (SEEG) recording were included in this study. The SEEG data were visually inspected and quantitatively analyzed. The narrowband oscillations and aperiodic components at seizure onset were parameterized. The frequency‐specific non‐linear correlation analysis was applied to the functional connectivity. The excitation/inhibition ratio (E:I ratio) reflected by the aperiodic slope was performed to evaluate the excitability.ResultsTwenty patients were included in the study, with 10 diagnosed with anterior cingulate epilepsy and 10 with anterior insular epilepsy. In both types of epilepsy, the correlation coefficient (h2) between the ACC and AIC at seizure onset exhibited a significantly higher value than that during interictal and preictal periods (p < 0.05). The direction index (D) showed a significant increase at seizure onset, serving as an indicator for the direction of information flow between these two brain regions with up to 90% accuracy. The E:I ratio increased significantly at seizure onset, with the seizure‐onset zone (SOZ) demonstrating a more pronounced increase compared to non‐SOZ (p < 0.05). For seizures originating from AIC, the E:I ratio was significantly higher in the AIC than in the ACC (p = 0.0364).ConclusionsIn the context of epilepsy, the ACC and AIC are dynamically coupled during seizures. The functional connectivity and excitability exhibit a significant increase at seizure onset. By analyzing connectivity and excitability, the SOZ in ACC and AIC can be identified. The direction index (D) serves as an indicator for the direction of information flow from SOZ to non‐SOZ. Notably, the excitability of SOZ changes more significantly than that of non‐SOZ.

Subthalamic nucleus dynamics track microlesion effect in Parkinson’s disease

“…Specifically, a decrease in spectral exponent (flatter spectrum) is indicative of heightened excitatory activity, while an increase in spectral exponent steeper spectrum) suggests an elevation in inhibitory activity. Furthermore, Lendner et al observed that individuals in an anesthetized state exhibit higher exponent as compared to their awake counterparts (Lendner et al, 2020b), and Yang et al reported that epileptic patients demonstrate lower exponents at the onset of seizures when contrasted with the preictal period (Yang et al, 2023). These investigations, which focus on disorders associated with the E/I balance, significantly enhance our comprehension of the intricate relationships between spectral indices and the equilibrium of excitatory and inhibitory mechanisms.…”