Role of electric fields in generation and propagation of epileptic activity

Event Date:
November 18th 9:00 AM - 10:00 AM

Meeting ID: 928 0482 8495 Passcode: 185518

Speaker: Muthumeenakshi Subramanian

Research Advisor: Prof. Durand

Role of electric fields in generation and propagation of epileptic activity

Neural recruitment in epilepsy occurs in part due to electric field (ephaptic) coupling in addition to synaptic mechanisms. We have shown that neural activity like theta waves, epileptic spikes and seizures can cross a physical transection in vivo using electric fields thus propagating independent of synaptic transmission. Hence, controlling the local electric field could suppress or cancel the generation of these epileptic events. We tested the hypothesis that clamping the local extracellular electric fields in a known focus can prevent the generation of epileptic spikes and seizures in the hippocampus in-vitro. 100 % of the induced epileptic activity originated from the temporal edge of the hippocampal slice. An extracellular voltage clamp system was connected to the recording electrode and applied a feedback current through stimulating electrodes to maintain the voltage equal to zero. When the feedback circuit was turned “on” the electric field produced by the applied current cancelled the local extracellular electric field involved in the generation of the epileptic events as evidenced by the clamp achieving 100% suppression of both epileptic spikes and seizure events. No spikes or seizures were observed in the septal region when the clamp was “on”. When the clamp was turned off both the spikes and seizure events recovered. An extracellular voltage clamp applied to a known epileptic focus can completely supress the generation of the epileptiform activity and prevent its propagation away from the focus. Although the spatial extent of the control is currently limited to the region around the recording site, this method could be effective to control seizure generation in a small known focus.