A Reproducible Cortical Model of Focal Epileptiform Activity with a Multi-Biomarker Analysis Pipeline

Abstract

The development of surface-based therapeutic strategies, including extracranial illumination and epicortical electrical or optoelectronic neuromodulation, requires experimental models in which focal pathological activity can be generated and monitored within an accessible cortical region. Here, we established an acute cortical model of focal epileptiform activity in anesthetized mice based on local microinjection of 4-aminopyridine (4-AP) into the barrel cortex. This preparation provides precise spatial and temporal control of the epileptiform focus while enabling simultaneous electrophysiological sampling across cortical depth. To objectively characterize the induced activity, we implemented a Python-based analysis pipeline integrating complementary electrophysiological biomarkers, including oscillatory power, multi-unit activity, pathological fast ripples (250-650 Hz), and epileptiform bursts. Local 4-AP administration produced robust increases in gamma (30-100 Hz) power, multi-unit firing (MUA), fast ripple and burst activity. Pharmacological sensitivity of the framework was evaluated using carbamazepine, which robustly attenuated 4-AP-induced increases in all biomarkers. Together, this study provides a reproducible experimental and analytical framework for investigating focal cortical epileptiform activity and for the future evaluation of pharmacological, optical, and electrical interventions targeting superficial cortical networks.