중첩경련 실험동물모델에서 경련단계에 따른 뇌파의 라아프노프 지수를 이용한 예비연구
A Preliminary Study for the Estimation of the First Positive Lyapunov Exponent of the EEG in Experimental Status Epilepticus Rats
이광수, 김영인, 이상봉, 김대진, 정재승, 김수용,
소속 상세정보
이광수 ( Lee Kwang-Soo )
가톨릭대학교 의과대학 신경과학교실
김영인 ( Kim Yeong-In )
가톨릭대학교 의과대학 신경과학교실
이상봉 ( Lee Sang-Bong )
가톨릭대학교 의과대학 신경과학교실
김대진 ( Kim Dai-Jin )
가톨릭대학교 의과대학 정신과학교실
정재승 ( Jeong Jae-Seung )
KAIST 물리학과
김수용 ( Kim Soo-Yong )
KAIST 물리학과
KMID : 0877219990030020150
Abstract
Background and Objectives: The hypothesis that brain is a nonlinear dynamic system exhibiting deterministic chaos has offered new methods to the investigation of information processing in the brain by analysis and classification of EEG signals. We used the first positiveLyapunov exponent (L1) which is one of indicator of nonlinear dynamic to evaluate the brain function in chemical seizure models
Methods: Lithium-Pilocarpine induced seizure model and kainic acid induced seizure model are used. From serial EEG according to seizure stages. 32.768 sec of data (16.384 data point) were recorded and digirized by a 12-bit analog-digital converter in an IBM PC. The data from serial EEG according to seizure stageswere analyzed for determining the L1. We used the time delays calculated by the method of mutual information to reconstruct the attactor. Time delays of 46-58 msec and enbedding dimensions of 13-19 were used for chemical seizure model. The L1 were calculated for 4 channels.
Results: The averaged valued of L1 were serially decreased in both lithium-pilocarpin model and kainic acid model according to increasing seizure stages.
Conclusion: Our results reveal the decrease of the chaotic activity according to increasing seizure stage. It is suggested that the brain has decreased information procedding and a less flexible neural network during seizure. However further evaluation is required because the significance of these changes are not confirmed.
키워드
리아프노프 지수; 뇌파; 중첩경련; 카오스; 리튬-필로카르핀; 카이닉산
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