Application of EEG non-linear analysis in cognitive function research / 中华神经科杂志

ABSTRACT

Objective To investigate the changes of non-linear dynamics properties of EEG under different mental tasks,and the application of non-linear dynamic analysis for cognitive function research. Methods EEG was recorded in 30 healthy university students under four states eyes closed,eyes open,mental arithmetic with eyes closed and graphic reasoning test with eyes open.Correlation dimension (D 2) and point-wise correlation dimension (PD 2) were calculated for all subjects.We also performed a surrogate data test in 5 randomized selected subjects. Results In all states tested,the results argued for the presence of non-linearity and fractal D 2 and PD 2.D 2 and PD 2 increased significantly during mental tasks as compared to the rest states (D 2 of above four states was 3.93,4.47,4.33 and 4.98 respectively).The results showed that values of D 2 and PD 2 fluctuated with time,which suggests an intermittent activation of the brain areas participated in the task.With non-linear dynamic analysis,there might be a working circuit from bilateral temporal lobes to the left frontal lobe and parental lobe under mental arithmetic task.Conclusions Through dynamic analysis based on D 2 and PD 2 topographic maps,we can see clearly the distribution of D 2 and PD 2 in the brain,the sequence and the degree of activation of the regions involved in the cognitive task under mental tasks.Dynamic and short-time non-linear analysis methods are more appropriate for the study of mental functions.Non-linear dynamic analysis might help us understand the working mechanism of brain during mental activities.