Analysis of Effective Connectivity in micro networks of Multi-Unit Activity and Local Field Potential in Human Mesial Temporal Lobe Epilepsy

COLLAVINI, SANTIAGO; KOCHEN, SILVIA; C.H. MURAVCHIK; ROMERO, U.

Virtual

Congreso; Congreso Argentino de Neurociencias; 2020

Sociedad Argentina de Investigación en Neurociencias

Intracranial electroencephalography (iEEG) is one of the most used procedures to identify the epileptogenic zone (EZ) in surgical treatment of drug resistant epilepsypatients [1, 2]. Since the 1950s, iEEG recordings have been performed using stereo-electroencephalography (SEEG). SEEG recordings are performed by multiplecontact depth electrodes placed inside the brain [3]. The electrode positioning is established based upon hypotheses about the localization of the EZ and electricalspread pathways [1, 4]. We have combined SEEG with micro-electrodes recordings in order to simultaneously record action potentials from individual neurons and theEEG generated by the surrounding neuronal network. This is an extraordinary opportunity to record single-unit activity from the EZ and its neighborhood. It is widelydiscussed the role of single-unit firing rate at seizure onset and during its propagation [5, 6]. In the present work, we report the duration, magnitude and spatial extent ofthe changes in neuronal firing seen during epileptic seizures and some technique limitations. It has long been recognized that the out degree connectivity pattern fromDirect Transfer Function (DTF) matrix of iEEG records is a biomarker of EZ and seizure onset zone (SOZ) with more than 80% of sensibility [7, 8]. Here, we analyzedthese patterns in a micro-scale