EXPLORING NETWORK RESILIENCE AND VULNERABILITY IN HUMAN EPILEPTIC BRAIN CIRCUITS THROUGH SPONTANEOUS AND EXPERIMENTALLY INDUCED CALCIUM DYNAMICS

Drug-resistant epilepsy is frequently described as a state of persistent network hyperexcitability, however, human brain circuits may still retain intrinsic homeostatic mechanisms that constrain the transition toward epileptiform activity. Whether and how such mechanisms fail in perturbed network states remains largely unexplored in human brain tissue. Identifying functional markers of network resilience versus vulnerability therefore requires experimental approaches capable of resolving population dynamics at cellular resolution during both spontaneous activity and experimentally perturbed network states. Here, we combine acute human brain slice preparations with two-photon calcium imaging to quantify spontaneous and pharmacologically induced network dynamics in human tissue resected from patients with focal drug-resistant epilepsy and from non-epileptic peritumoral access tissue. Neuronal populations are bulk-loaded with chemical calcium indicators and imaged using two-photon calcium microscopy under baseline conditions as well as during pro-convulsant manipulations designed to induce controlled perturbations of neuronal network states. Calcium signals are analyzed using an automated, bias-minimized pipeline enabling quantification of single-cell activity, population recruitment, and inter-neuronal correlation structure. Preliminary analyses may indicate an increased probability of spontaneous activity in epileptic tissue, and under experimentally perturbed conditions, network recruitment and functional coupling further increase compared to non-epileptic peritumoral access tissue, consistent with increased network vulnerability. Overall, this approach enables the identification of dynamic features associated with network-level processes underlying failure and recovery in human epileptic circuits.