Activation of specific neuronal networks leads to different seizure onset types.
|Title||Activation of specific neuronal networks leads to different seizure onset types.|
|Publication Type||Journal Article|
|Year of Publication||2016|
|Authors||Shiri Z, Manseau F, Lévesque M, Williams S, Avoli M|
|Date Published||2016 Mar|
OBJECTIVE: Ictal events occurring in temporal lobe epilepsy patients and in experimental models mimicking this neurological disorder can be classified, based on their onset pattern, into low-voltage, fast versus hypersynchronous onset seizures. It has been suggested that the low-voltage, fast onset pattern is mainly contributed by interneuronal (γ-aminobutyric acidergic) signaling, whereas the hypersynchronous onset involves the activation of principal (glutamatergic) cells.METHODS: Here, we tested this hypothesis using the optogenetic control of parvalbumin-positive or somatostatin-positive interneurons and of calmodulin-dependent, protein kinase-positive, principal cells in the mouse entorhinal cortex in the in vitro 4-aminopyridine model of epileptiform synchronization.RESULTS: We found that during 4-aminopyridine application, both spontaneous seizure-like events and those induced by optogenetic activation of interneurons displayed low-voltage, fast onset patterns that were associated with a higher occurrence of ripples than of fast ripples. In contrast, seizures induced by the optogenetic activation of principal cells had a hypersynchronous onset pattern with fast ripple rates that were higher than those of ripples.INTERPRETATION: Our results firmly establish that under a similar experimental condition (ie, bath application of 4-aminopyridine), the initiation of low-voltage, fast and of hypersynchronous onset seizures in the entorhinal cortex depends on the preponderant involvement of interneuronal and principal cell networks, respectively.
|Alternate Journal||Ann. Neurol.|
|PubMed Central ID||PMC4878884|
|Grant List||74609 / / Canadian Institutes of Health Research / Canada |
8109 / / Canadian Institutes of Health Research / Canada
MOP119340 / / Canadian Institutes of Health Research / Canada