A Study of Neural Excitability in Human Patients Undergoing Brain Tissue Resections for the Treatment of Medically Resistant Epilepsy 

 

 

This study aims to investigate the correlation between changes in intrinsic cell properties within resected areas and surgical outcomes in patients undergoing epilepsy surgery. Specimens collected from patients with surgical resection of the seizure onset zone (SOZ) and surrounding tissue will be analyzed. During surgery and upon resection of the tissue, the tissue block will be placed in an ice-cold sucrose-modified ACSF containing (in mM) 210 sucrose, 10 NaCl, 1.9 KCl, 1.2 Na2HPO4, 33 NaHCO3, 6 MgCl2, 1 CaCl2, 10 glucose, and 2 kynurenic acid; pH 7.3–7.4 saturated with 95% O2-5% CO2 (Gonzalez-Burgos et al., 2015). The biopsy tissue blocks will be kept in a tightly sealed plastic container placed on ice and transported to the Robarts 7th floor (slice electrophysiology laboratory) in shock-absorbing containers. The study involves functional exploration of single neurons using patch clamp techniques on resected tissue, aiming to reveal increased excitability that may correlate with poor surgical outcomes. Additionally, neuronal morphology will be reconstructed to understand the complexity of arborizations, with the anticipation that increased arborization in pyramidal cells may indicate a worse outcome. The main objectives include identifying structural and functional properties of neurons in patients with medically resistant epilepsy, conducting intracellular recordings in extracted tissue slices, and building a database of single neuron electrophysiology as a resource for modeling epileptic networks. The study also includes collection of relevant clinical data, including tissue from other sources to be used as a control group for comparison. Patients will be contacted via telephone to participate and will provide written consent either before surgery in the clinic or if they participate in the SNSX study, in which case they are able to sign consent during the MRI appointment.

 

Inclusion criteria:

  • For epilepsy participants: Patients ages 18 or older with medically resistant epilepsy who are undergoing surgical resection of SOZ tissue who speak English.
  • For control participants: Patients ages 18 or older who do not have a previous diagnosis of epilepsy, and who are undergoing surgical resection of another lesion unrelated to epilepsy.

 

Exclusion criteria:

  • For epilepsy participants: Patients are not 18 years or older and who are not undergoing surgical resection of SOZ tissue and do not speak English.
  • For control participants: Patients are not 18 years or older or older, have a previous diagnosis of epilepsy, and/or who are undergoing surgical resection of a lesion related to epilepsy.

 

  Principal Investigator: Dr. Ana Suller Marti

 

Mariam Elnazali (Research Assistant), Homa Vahidi (Research Assistant), Alaa Taha (PhD student), and Dr. Greydon Gilmore (neurophysiologist) will obtain verbal consent from patients via telephone and collect written consent when they accompany patients for the SNSX study, or prior to their surgery at an appointment.