Effects of Transient Epileptiform Activity on Long-Term Synaptic and Network Properties in Turtle Cortex.
Abstract number :
2.010
Submission category :
Year :
2001
Submission ID :
252
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
B.K. Clinton, Neurobiology & Behavior, Columbia University, New York, NY; A.C. Flint, M.D., Ph.D., Neurology, Columbia University, New York, NY; A.R. Kriegstein, M.D.,Ph.D., Neurology, Columbia University, New York, NY
RATIONALE: In vitro brain slice preparations have been useful to study epileptiform activity. However, the cellular mechanisms that generate ictal activity and the extent to which ictal activity influences postictal synaptic connectivity are poorly understood.
METHODS: We used coronal slices of the juvenile turtle P. scripta elegans, a model capable of generating spontaneous epileptiform activity, to study activity-dependent changes in synaptic connectivity and network properties. Cortical slices including the dorsal and medial cortex were isolated for whole-cell patch and dual recording.
RESULTS: In ACSF, the pyramidal neurons situated in a single cellular layer were active but did not exhibit rhythmic depolarizations. Bath application of the GABA-A receptor antagonist bicuculline (20mM) led to spontaneous discharges with an inter-event interval of 4-5 seconds. Experiments using dual recording and microdissection of slices revealed that epileptiform activity originates in the medial cortex. Stimulation in the molecular layer was used to evoke EPSPs before and after application of bicuculline to test the hypothesis that a brief period of epileptiform activity may be capable of altering long-term synaptic strength and seizure threshold.
CONCLUSIONS: Understanding seizure-induced changes in synaptic connectivity in the relatively simple turtle cortex may help evaluate synaptic changes related to epileptic events.
Support: 2 R01 NS21223-15
Role of Intercellular Signaling in Neocortical Development