Chaotic and stochastic dynamics of epileptiform-like activities in sclerotic hippocampus resected from patients with pharmacoresistant epilepsy

PLoS Comput Biol. 2022 Apr 13;18(4):e1010027. doi: 10.1371/journal.pcbi.1010027. eCollection 2022 Apr.

Abstract

The types of epileptiform activity occurring in the sclerotic hippocampus with highest incidence are interictal-like events (II) and periodic ictal spiking (PIS). These activities are classified according to their event rates, but it is still unclear if these rate differences are consequences of underlying physiological mechanisms. Identifying new and more specific information related to these two activities may bring insights to a better understanding about the epileptogenic process and new diagnosis. We applied Poincaré map analysis and Recurrence Quantification Analysis (RQA) onto 35 in vitro electrophysiological signals recorded from slices of 12 hippocampal tissues surgically resected from patients with pharmacoresistant temporal lobe epilepsy. These analyzes showed that the II activity is related to chaotic dynamics, whereas the PIS activity is related to deterministic periodic dynamics. Additionally, it indicates that their different rates are consequence of different endogenous dynamics. Finally, by using two computational models we were able to simulate the transition between II and PIS activities. The RQA was applied to different periods of these simulations to compare the recurrences between artificial and real signals, showing that different ranges of regularity-chaoticity can be directly associated with the generation of PIS and II activities.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Epilepsy*
  • Epilepsy, Temporal Lobe* / surgery
  • Hippocampus / surgery
  • Humans

Grants and funding

This work was partially supported by: Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (https://www.gov.br/capes) (code 001, granted to E.A.C. and C.A.S.), Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) (https://www.gov.br/cnpq/): 442563-2016/7, granted to J.F., Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (https://fapesp.br/): 15/24691-8, granted to C.A.S., CNPq/MCT-Instituto Nacional de Neurociência Translacional (INNT): 573604/2008-8, granted to E.A.C., and Universidad Nacional Autónoma de Honduras (CU-O-041-05-2014, granted to S.Z.R-G.). The sponsors/funders did not play any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.