Neural Circuits and Systems Neuroscience
Author: Alejandro Nasimbera Nasimbera | email: alejandro_nasimbera@hotmail.com
Alejandro Nasimbera 1°, Santiago Cordisco Gonzalez 1°, Brenda Giagante 1°, Silvia Oddo 1°, Ines Mintz 1°, Patricia Solis 1°, Juan Pablo Princich 1°, Pablo Seoane 1°, Silvia Kochen 1°
1° ENyS CONICET – Hospital de Alta Complejidad en Red El Cruce “Néstor Kirchner” – Universidad Nacional Arturo Jauretche
Patients with focal drug-resistant epilepsy could benefit from surgical treatment if the epileptogenic zone(EZ) is identified. Intracranial electroencephalography with macro-microelectrodes allows the recording of local field potentials(LFP), the extracellular activity of multiple neurons(MUA) and the activity of single neurons(SN). Objective: to evaluate the behavior of the SN during epileptic seizures. MATERIALS AND METHODS: Macro-microelectrodes were implanted in patients with drug-resistant epilepsy and the signal was recorded with the Cervello system filtered between 1-9000 Hz and sampled at 30 kHz. SN activity were analyzed in 100-ms windows from 5 min before ictal onset and 1 min after in the ictal onset zone (IOZ) and in the propagation zone(ZP). Firing rates(FR), stereotypy, and Fano Factor(FF) were determined. The signal was processed in MATLAB using WAVE_CLUS and FieldTrip. RESULTS: A total of 150 SN from 4 patients in 59 seizures were analyzed, 78 in IOZ and 72 in PZ. As for the firing rate, three distinct ictal patterns of the SN were identified: increased, decreased and unchanged FR. The FF showed a significant increase in the neurons involved in the IOZ. All neurons involved in the IOZ showed a high degree of stereotypy. CONCLUSIONS: The analysis of the behavior of the SN allowed to describe patterns of ictal activity, contributing to understand the dynamics neural networks during seizures. Future analyzes could identify biomarkers of the EZ at the microscale.