Neuronal desynchronization as a trigger for seizure generation.
IEEE Trans Neural Syst Rehabil Eng
; 16(1): 62-73, 2008 Feb.
Article
em En
| MEDLINE
| ID: mdl-18303807
ABSTRACT
Experimental reports have appeared which challenge the dogma that epileptic seizures arise as a consequence of neuronal hypersynchronization. We sought to explore what mechanisms that desynchronize neuronal firing could induce epileptic seizures. A computer model of connections in a mammalian hippocampal slice preparation was constructed including two recently-reported distinct inhibitory feedback circuits. When inhibition by interneurons that synapse on pyramidal dendrites was decreased, highly localized seizure-like bursting was observed in the CA3 region similar to that which occurs experimentally under GABAergic blockade. In contrast, when inhibition by interneurons that synapse in the axosomatic region was similarly decreased, no such bursting was observed. However, when this transient inhibition was increased, normal coordinated spread of excitation was interrupted by high-frequency localized seizure-like bursting. The increase of this inhibitory input resulted in decreased cell coupling of pyramidal neurons. A decrease in phase coherence was initially observed until seizure-like activity initiated causing a net increase in coherence as has been observed in epileptic patients. These results provide a possible pathway in which a decrease in synchronization could provide the trigger for inducing epileptiform activity.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Convulsões
/
Sincronização Cortical
/
Interneurônios
Tipo de estudo:
Risk_factors_studies
Limite:
Humans
Idioma:
En
Revista:
IEEE Trans Neural Syst Rehabil Eng
Assunto da revista:
ENGENHARIA BIOMEDICA
/
REABILITACAO
Ano de publicação:
2008
Tipo de documento:
Article
País de afiliação:
Estados Unidos