Study of social behavior and cortical rhythm in an animal model of temporal lobe epilepsy

Abstract

Epilepsy is a diverse set of chronic neurological disorders. It is important to focus on the aspect of etiology, but the most important concerns of patients involves social aspects. Although this issue is gradually surfacing, the neural mechanisms underlying the social behavioral alterations are still poorly understood, and the onset of psychiatry-related social behavioral dysfunctions in epilepsy is still an unresolved issue. In this study, we investigated psychiatry-related social behavioral alterations and cortical rhythmic changes during latent and chronic epileptic stages in the pilocarpine mouse model of temporal lobe epilepsy (TLE). We found that both latent and chronic epileptic mice exhibited severe impairments in the social behavioral tasks, such as reduced sociability, reduced social interactions, and the extinction of social novelty preference, observational social fear learning, and enhanced defensiveness. Next, we found aberrant brain activities in both the latent and chronic epileptic period mice through the social interaction task using juvenile mouse simultaneously with Video-EEG recordings. They had enhanced delta (1-4 Hz) band power and reduced the alpha (8.5-12 Hz) and gamma (30-55 Hz) band power in the baseline behavioral state. Interestingly, in the social interaction state, abnormal theta (4.5-8 Hz ), alpha, and gamma band power seemed to correlate the outcomes of social behavior tasks. Thus, we suggest that social deficits and aberrant brain activities develop at the early stage of epileptogenesis before SRSs develop. This knowledge helps to understand psychiatry-related social behavior of patients with epilepsy and other psychiatric brain disorders, and may improve the medical management and the at-risk patients’ quality of life from initial injuries that can develop into epilepsy.