149 | Behavioral markers of epileptogenesis and pharmacoresistance in a longitudinal pilocarpine model of temporal lobe epilepsy

Nicolò Ricciardi¹, Miriana Scordino¹, Giulia Urone¹, Miriam Buttacavoli¹, Giuseppa Mudò¹, Pierangelo Sardo¹, Giuseppe Giglia^1|2, Valentina Di Liberto¹, Giuditta Gambino¹ | ¹Department of Biomedicine, Neuroscience and Advanced Diagnostics, University of Palermo, Italy; ²Euro Mediterranean Institute of Science and Technology - IEMEST, Palermo, Italy.

Abstract

Temporal lobe epilepsy (TLE) represents a chronic neurological disorder characterized by dynamic alterations in neural networks, behavior, and responsiveness to antiepileptic drugs, although integrated longitudinal studies remain scarce. In this study, we examined the temporal trajectory of behavioral alterations associated with TLE progression using a pilocarpine-induced rat model. Assessments were conducted at five experimental stages: baseline (T0), acute phase (T1, 1 week post–status epilepticus), latent phase (T2, 4 weeks), chronic phase (T3, 8 weeks), and after assessment of phenobarbital responsiveness (T4, 12 weeks). Drug-resistance was evaluated by recording the number of seizures through continuous video-monitoring from chronic phase to T4. Our findings revealed progressive, phase-specific alterations of behavioral patterns. From the acute to the chronic phase, epileptic rats exhibited a hypermotor phenotype, characterized by increased exploratory activity and reduced immobility, together with reduced anxiety-like behavior in the light–dark box test. In parallel, natural behaviors progressively deteriorated, as shown by decreased burrowing activity and the emergence of hedonic drive dysregulation. During epileptogenesis, significant impaired memory consolidation and retrieval emerged in the novel object recognition test. Furthermore, after phenobarbital treatment, a distinct pharmacoresistant epileptic subgroup emerged, displaying a behavioral phenotype with specific functional signatures. Collectively, these data offer a comprehensive longitudinal framework for TLE progression and highlight candidate translational biomarkers relevant for epileptogenesis and antiepileptic drug resistance.