Neuronal Bursting Properties in Focal and Parafocal Regions in Pediatric Neocortical Epilepsy Stratified by Histology

• DOI: 10.1097/wnp.0b013e3181fe06d8
• Publication Date: 2010-11-01T07:24:00Z
• Authors: Charles J. Marcuc...; Andrew K. Tryba; Wim van Drongelen; Henner Koch; Jean Charles Viemari; Fernando Peña-Ortega; Erin L. Doren; Peter Pytel; Marc Chevalier; Ana Mrejeru; Michael H. Kohrman; Robert E. Lasky; Sean M. Lew; David M. Frim; Jan-Marino Ramirez
• Keywords: Male; Neurons; Epilepsy; N-Methylaspartate; Patch-Clamp Techniques; Adolescent; Action Potentials; Neocortex; In Vitro Techniques; Bicuculline; Electric Stimulation; Piperazines; 03 medical and health sciences; 0302 clinical medicine; Child, Preschool; Phosphopyruvate Hydratase; Excitatory Amino Acid Agonists; Humans; Female; GABA-A Receptor Antagonists; Child; Excitatory Amino Acid Antagonists

To test the hypothesis that focal and parafocal neocortical tissue from pediatric patients with intractable epilepsy exhibits cellular and synaptic differences, the authors characterized the propensity of these neurons to generate (a) voltage-dependent bursting and (b) synaptically driven paroxysmal depolarization shifts. Neocortical slices were prepared from tissue resected from patients with intractable epilepsy. Multiunit network activity and simultaneous whole-cell patch recordings were made from neurons from three patient groups: (1) those with normal histology; (2) those with mild and severe cortical dysplasia; and (3) those with abnormal pathology but without cortical dysplasia. Seizure-like activity was characterized by population bursting with concomitant bursting in intracellularly recorded cortical neurons (n = 59). The authors found significantly more N-methyl-D-aspartic acid-driven voltage-dependent bursting neurons in focal versus parafocal tissue in patients with severe cortical dysplasia (P < 0.01). Occurrence of paroxysmal depolarization shifts and burst amplitude and burst duration were significantly related to tissue type: focal or parafocal (P < 0.05). The authors show that functional differences between focal and parafocal tissue in patients with severe cortical dysplasia exist. There are functional differences between patient groups with different histology, and bursting properties can be significantly associated with the distinction between focal and parafocal tissue.