复杂性与脑功能

COMPLEXITY AND BRAIN FUNCTION

EEG代表了大脑活动的一种电信号,但是用它来研究脑的功能活动是非常困难的.近年来由于非线性动力学的新发展,为我们提供了从一维EEG的时间序列提取脑的多维动力系统的信息,其中一个重要的方法是测量“关联维数”,但发现EEG是非平稳的混沌态,分维的知识只能给出系统的几何特征.而非平稳性表现出的是动态特性.因此我们对EEC的“复杂性”进行了研究,并与其它已知的标准的奇异吸引子做了比较.

In our common sense the meaning of something simple or complex are very clear, however it is difficult to give a precise definition and quantification of 'complexity'. In this paper we will show by the definition of Lempel and Ziv with the algorithms of Kasper and Schuster that the complexity of a time series may be computed. EEG is more complex than that of Lorenz and Rossler str-ange attractors and its complexity is closely related to the functional states.