Correlation of Extracellular Epileptiform Discharges with the Pathological Degree of Cortical Dyslamination in Human Malformation of Cortical Development (MCD) Neocortex.
Abstract number :
2.035
Submission category :
Year :
2001
Submission ID :
2714
Source :
www.aesnet.org
Presentation date :
12/1/2001 12:00:00 AM
Published date :
Dec 1, 2001, 06:00 AM
Authors :
H. Seo, B.S., Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea; Y.J. Lee, B.S., Neurosurgery, Seoul National University Hospital, Seoul, Republic of Korea; Y. Choi, M.D., Pathology, Seoul National University Hospital, Seoul, Repu
RATIONALE: Malformation of cortical development (MCD) corresponds to a disruption of the normal cortical lamination with inherent epileptogenesis. However, little is known that there would be difference between severity of cortical dyslamination and electrical abnormality in MCD.
METHODS: Field potential was recorded in slices of human neocortex obtained during surgery for the treatment of epilepsy associated with MCD (n=9 patients). The event duration and frequency were compared with the severity of cortical dyslamination; mild, and moderate to severe in Nissl stain.
RESULTS: Ictal-like epileptiform discharges, along with isolated field potentials, were induced by bath application of 4-aminopyridine (4AP, 100[mu]M). In contrast to clustering of interictal spikes (duration, 3-8 seconds; interval of occurrence, 5-80 seconds) in the mild MCD (n=5), prolonged ictal-like discharges (duration, 6-117 seconds; interval of occurrence, 5-25 seconds, up to 24Hz) were recorded in the moderate to severe MCD (n=4). In case of isolated field potentials, there was also difference. In contrast to isolated negative events in the mild group (duration, 0.7-3 seconds; intervals of occurrence, 4-40 seconds), they were faster (duration, 0.4-3 seconds; intervals, 2-26 seconds) in the moderate to severe group. The response of the moderate to severe group was longer in duration and shorter in interval than that of mild group.
Twenty minutes after 4AP treatment, we compared the oscillation frequency. In the mild group, the oscillation frequency was slower than that in the moderate to severe group (mild, 0.6-3 Hz; moderate to severe, 6-22 Hz).
Ictal-like discharges were abolished by N-methyl-D-aspartate receptor antagonists (D-APV, 100[mu]M). However, the isolated field potentials continued to occur synchronously during excitatory transmission blockade. There was no discernible difference between mild and moderate to severe groups.
CONCLUSIONS: Our study demonstrated that MCD tissue in vitro had an intrinsic ability to generate ictal-like epileptiform discharges with 4AP, and the frequency and duration of synchronous activities were correlated with the degree of cortical dyslamination.
Support: This work was supported in part by a grant from the Korean Ministry of Health and Welfare (HMP-99-N-02-0003).