The Devil’s in the Details: How to Harness Inhibition for Seizure Control

Abstract

Paradoxical Effects of Optogenetic Stimulation in Mesial Temporal Lobe Epilepsy Levesque M, Chen LY, Etter G, et al. Ann Neurol. 2019;86(5):714-728. doi:10.1002/ana.25572. Objective: To establish the effects induced by long-term, unilateral stimulation of parvalbumin (PV)-positive interneurons on seizures, interictal spikes, and high-frequency oscillations (80-500 Hz) occurring after pilocarpine-induced status epilepticus (SE)—a proven model of mesial temporal lobe epilepsy (MTLE)—in transgenic mice expressing or not expressing ChR2. Methods: Both PV-ChR2 (n = 6) and PV-Cre (n = 6) mice were treated with pilocarpine to induce SE. Three hours after SE onset, unilateral optogenetic stimulation (450 nm, 25 mW, 20 ms pulses delivered at 8 Hz for 30 seconds every 2 minutes) of CA3 PV-positive interneurons was implemented for 14 continuous days in both groups. Results: Rates of seizures (P