216 | Neuronal firing during seizures in epilepsy surgery candidates

Neural Circuits and Systems Neuroscience

Author: Alejandro Nasimbera | Email: alejandro_nasimbera@hotmail.com

Alejandro Nasimbera , Santiago Cordisco , Brenda Giagante , Juan Pablo Princich , Pablo Seoane , Silvia Kochen

1° ENyS CONICET  Hospital de Alta Complejidad en Red El Cruce Néstor Kirchner – Universidad Nacional Arturo Jauretche.

Patients with drug-resistant epilepsy could benefit from surgery if the epileptogenic zone(EZ) is identified. Intracranial electroencephalography with macro-microelectrodes records single neuron (SN) activity during seizures. Our goal is to evaluate SN behavior during seizures.
Macro-microelectrodes were implanted in patients with drug-resistant epilepsy, recording signals via the Cervello system at 30 kHz. Firing rates (FR) of SN activity were analyzed in 15-second intervals before and after ictal onset. Electrodes covered ictal onset zone (IOZ), close propagation zone (CPZ), and distal propagation zone (DPZ). For comparisons, repeated measures ANOVA was employed. Signal processing was done in MATLAB using WAVE_CLUS and FieldTrip.
A total of 80 epileptic seizures from 11 different patients were analyzed; 1932 groups of neurons were identified, 257 in the EZ, 607 in the CPZ, and 1033 in the DPZ. A statistically significant difference was found in the firing rates before and after the ictal onset. In patients with temporal lobe epilepsy, there was a significant difference between firing rates of neurons ipsilateral to the EZ and those in contralateral regions.
The analysis of the behavior of the SN contributes to our comprehension of neural network dynamics during seizures, with particular significance for temporal lobe epilepsy cases where it may aid in lateralization determination.