Pre-ictal increase in theta synchrony between the hippocampus and prefrontal cortex in a rat model of temporal lobe epilepsy.

Pre-ictal increase in theta synchrony between the hippocampus and prefrontal cortex in a rat model of temporal lobe epilepsy.
Exp Neurol. 2016 Mar 4;
Authors: Broggini AC, Esteves IM, Romcy-Pereira RN, Leite JP, Leão RN
Abstract
The pathologically synchronised neuronal activity in temporal lobe epilepsy (TLE) can be triggered by network events that were once normal. Under normal conditions, hippocampus and medial prefrontal cortex (mPFC) work in synchrony during a variety of cognitive states. Abnormal changes in this circuit may aid to seizure onset and also help to explain the high association of TLE with mood disorders. We used a TLE rat model generated by perforant path (PP) stimulation to understand whether synchrony between dorsal hippocampal and mPFC networks is altered shortly before a seizure episode. We recorded hippocampal and mPFC local field potentials (LFP) of animals with spontaneous recurrent seizures (SRS) to verify the connectivity between these regions. We showed that SRS decrease hippocampal theta oscillations whereas coherence in theta increases over time prior to seizure onset. This increase in synchrony is accompanied by a stronger coupling between hippocampal theta and mPFC gamma oscillation. Finally, using Granger causality we showed that hippocampus/mPFC synchrony increases in the pre-ictal phase and this increase is likely to be caused by hippocampal networks. The dorsal hippocampus is not directly connecte...

Source: Experimental Neurology - March 4, 2016 Category: Neurology Authors: Broggini AC, Esteves IM, Romcy-Pereira RN, Leite JP, Leão RN Tags: Exp Neurol Source Type: research