Authors :
Presenting Author: Nigel Pedersen, MBBS – University of California, Davis
Ashley Ragu, MBBS, PhD – Emory University; Veeresh Shivamurthy, MD – University of Connecticut; Joshua Chern, MD, PhD – Children's Healthcare of Atlanta; Robert Gross, MD, PhD – Emory University; Jon Willie, MD PhD – Washington University; Raymond Dingledine, PhD – Emory University; Ammar Kheder, MD – Children's Healthcare of Atlanta
Rationale: The piriform cortex is highly epileptogenic in rodents. Recent surgical outcomes in human studies suggest a benefit in resection of the piriform cortex in medial temporal lobe epilepsy. However, the electrophysiology of the piriform cortex in human epilepsy has not been studied. We sought to examine the electrophysiological role of the piriform cortex in the epileptogenic network in patients with suspected temporal lobe epilepsy.
Methods: This case-series study relied on identifying the piriform cortex in imaging and examining the electrophysiology of seizures from depth electrodes, from Emory University Hospital or Children’s Healthcare of Atlanta. We included patients with frontotemporal or temporal lobe hypotheses undergoing stereo-electroencephalographic (SEEG) studies and with the rare scenario of one or more electrode contacts in the piriform cortex.
Results: Twenty-two patients were included. Only one patient showed involvement of the piriform cortex at seizure onset, associated with an olfactory aura; two showed early piriform cortex involvement, and the remaining showed late or no piriform cortex involvement. Electrical stimulation of the piriform cortex resulted in after-discharges in three patients and reproduced a habitual seizure in one.
Conclusions: These findings contrast with surgical outcome studies and raise the prospect that the piriform cortex is typically not involved in the epileptogenic network in patients with non-lesional temporal lobe epilepsy.
Funding: NIH K08NS105929, R21NS122011, and a CURE Epilepsy Award partly supported NPP. RJD is supported by NIH 1R01NS112308. NIH R01-MH120194 and P41-EB018783 support JTW.