Authors :
Presenting Author: Belén Diaz-Fernandez, PhD – Institut de Psychiatrie et Neurosciences de Paris
David Henao-Herreño, PhD – CIRB, College de France, Paris; Elena Dossi, PhD – CIRB, College de France, Paris; Capelle Laurent, MD – Pitié-Salpêtrière Hospital, Paris; Johan Pallud, MD, PhD – Saint-Anne Hospital, Paris; Nathalie Rouach, PhD – CIRB, College de France, Paris; Michel LeVanQuyen, PhD – LIB, Paris; Gilles Huberfeld, MD, PhD – CIRB, College de France, Paris
Rationale: As seizure occurrence is unpredictable, focusing on the preictal period is key to better understand the physiopathology of seizure initiation, and to develop new tools for “seizure high-risk periods” detection. The use of postsurgical human tissue provides a unique opportunity to study preictal dynamics, such as the transition from the interictal state to the seizure in cortex slices recorded with high spatial resolution using MultiElectrode Array (MEA) (1). Our aim is to describe the spatio-temporal dynamics of extracellular neuronal activities during the transition to an ictal-like event (ILE), by assessing multiscale electrophysiological data including field potentials (FP), multiunit activity (MUA), and high-frequency oscillations (HFO), recorded with MEA, in human postoperative tissues of epileptic patients suffering from gliomas.
Methods: Forty-four peritumoral neocortical slices from 27 glioma patients were included in this study. Extracellular recordings were performed with a 120 contacts MEA, at a basal state with artificial cerebrospinal fluid (aCSF) during which spontaneous interictal discharges (IIDs) are generated by these epileptic tissues, and during the transition to ILE, induced by bathing slices with an excitatory milieu (6K-lowMg aCSF).
Results: The preictal period was characterized by the emergence of preictal discharges (PIDs), appearing
898.60±562.22 seconds after the addition of the ictogenic solution. PIDs presented larger and progressively increasing amplitudes (
87.39±42.97 µV) and rising slopes
(1.4±0.71), before reaching a steady state, compared to spontaneous IIDs (amplitude
13.27 ± 5.88 µV and rising slope 0.64±0.38) that remained stable
(Mann-Whitney test, p< 0.001