[Abstract Title]. - Society for Neuroscience

Disclosures: K.P. Lillis, None; M.A. Kramer, None; J. Mertz, None; J.A. White, None.
Poster
250. Epilepsy: Networks
Time: Sunday, November 16, 2008, 1:00 pm - 5:00 pm
Program#/Poster#: 250.13/V25
Topic: C.06.f. Circuits and systems
Support: NSF CAREER Grant PHY-0547647
Title: Spatiotemporal patterns of phase synchronization in voltage-sensitive dye imaging of
4AP-induced epileptic seizures in the rat neocortex
Authors: *D. TAKESHITA, V. TSYTSAREV, S. BAHAR;
Dept Physics & Astronomy, Univ. Missouri-St. Louis, St. Louis, MO
Abstract: We use voltage-sensitive dye imaging to investigate how spatiotemporal patterns of
synchronization change during drug-induced in vivo neocortical seizures in rats. Focal seizures
were caused by the potassium channel blocker 4-aminopyridine (4AP).
The neocortex was stained with the voltage-sensitive dye RH-1691. The intensity changes in dye
fluorescence were imaged using a 16-bit CCD camera and are consistent with the signal from
local field potential recording. After the administration of 4AP, seizure events were triggered by
electrical stimulation. Imaging data before electrical stimulation was collected as a reference.
The power spectrum was calculated, using a sliding window, for voltage sensitive dye recordings
both before and during the seizure event. The signal from each pixel after electrophysiological
seizure onset was classified as part of the seizure event if the power spectrum was higher a
threshold value determined from the pre-seizure state.
The epileptic area increases quickly at the beginning of a seizure event and stays almost constant
throughout the duration of the seizure. A sudden decrease of the area is observed at the end of
each seizure event. We applied phase synchronization analysis to the voltage-sensitive dye
signals from multiple pairs of pixels throughout the seizure area. We observe a dramatic increase
in synchronization during the seizure events. We also observe that closer pairs of pixels show
stronger synchronization than pairs separated by a larger distance. Even widely separated pairs of
pixels within the seizure area, however, show a significant increase in synchronization during the
seizure event.
Disclosures: D. Takeshita, None; V. Tsytsarev, None; S. Bahar, None.