Nonlinear causality analysis of EEG signals evoked by manual acupuncture

Manual acupuncture (MA), as a mechanical action, can be equivalent to an external stimulus to the neural system. To explore the effect of MA on the information transformation of the brain, we design an experiment that acupuncture at Zusanli acupoint of right leg with four different frequencies to obtain electroencephalograph (EEG) signals. Neural system is a complex nonlinear dynamics system that possesses strong nonlinear characteristic, so we introduce nonlinear Granger causality method to investigate the effect of MA on the causality relationship between different brain regions. It is found that different MA has different effect on the causality relationship between different brain regions, and that acupuncture at right leg acupoint obviously affects the information transformation on contralateral hemisphere.