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目的 从亚慢性染铅大鼠中枢神经系统电活动的变化 ,寻找铅中毒早期诊断敏感指标。方法 利用脑电信号及功率谱的混沌时间序列分析方法进行研究。结果 从染铅大鼠额、顶、枕部获取的脑电信号进行功率谱分析 ,在染铅组与对照组、各染铅组之间均未发现明显差异。脑电信号的混沌时间序列分析所得的分形维数及第一Lyapunov指数的值均表明脑电波具有混沌现象的典型特征。正常大鼠在额部、顶部和枕部脑电分形维数为 3.74± 0 .0 9、2 .2 3± 0 .31、4.2 8± 0 .43;低剂量组染铅大鼠的对应值分别是 7.77± 0 .34、7.78± 0 .6 4、7.6 5± 0 .95 ,两者间分形维数的差异有显著性 (P <0 .0 1)。各剂量组和对照组第一Lyapunov指数均为正值。 结论 铅接触大鼠脑电信号具有混沌特性 ,利用混沌时间序列分析为早期诊断提供灵敏的检测指标是可能的。
Objective To investigate the changes of electrical activity in the central nervous system of sub-chronic lead-exposed rats and find out the sensitive indexes for the early diagnosis of lead poisoning. Methods The method of chaotic time series analysis using EEG signal and power spectrum was studied. Results Power spectrum analysis of EEG signals obtained from the frontal, apex and occipital of lead-exposed rats showed no significant difference between the lead-exposed and control groups and the lead-exposed groups. The fractal dimension and the value of the first Lyapunov exponent in chaotic time series analysis of EEG indicate the typical characteristics of brain waves with chaos. EEG fractal dimension of the normal, frontal and occipital parts of the normal rats were 3.74 ± 0. 0 9,2. 23 ± 0. 31 and 42 8 ± 0. Respectively 7.77 ± 0.34, 7.78 ± 0.64, 7.65 ± 0.95, the difference between the fractal dimensions was significant (P <0.01). The first Lyapunov exponent in each dose group and control group was positive. Conclusions Lead-exposed rat brain electrical signals have chaotic characteristics. It is possible to use chaotic time series analysis to provide sensitive detection indexes for early diagnosis.