Brain Activation during Qigong Meditation: Comparison of EEG and Optical Topography Results

Many studies have shown a power increase of alpha activity and sometimes a high-amplitude theta rhythm over the frontal lobes during meditation. But few studies have discussed the related brain areas. In this paper, we studied qigong meditation by employing a newly developed technique, optical topography to identify cortical areas specifically involved in the meditation state. As comparison, EEG results on the same task are also presented. Compared with the control state, our EEG analysis results showed statistically significant increases(p<0.001)of alpha power in Fp1 and O1 areas, while statistically significant increases (p<0.001)of the theta power were found in Fz, C3, C4, T5 and T6 areas. In the analysis of optical topography, the results varied considerably in different regions. In the frontal areas, with the progression of the qigong meditation task, after decreasing for some time, the concentration of oxygenated hemoglobin (HbO2) and total hemoglobin (tHb) increased together. While in the parietal-occipital areas, both of them decreased continuously. On the other hand, concentration of deoxygenated hemoglobin (deoxy-Hb) increased slightly during the qigong meditation state, then declined gradually to the original level during the control state in the frontal areas, but remained constant in the parietal-occipital areas. Comparison to other studies on mental concentration tasks employing near-infrared spectroscopy suggested that “revival after inhibition of the frontal lobes” could be one of the characteristics of the brain activity during qigong meditation.