Research on Cardiovascular System and CNS Electrophysiological Phenomena under Zen Meditation

• Main Authors: Chuan-Yi Liu, 劉權毅
• Other Authors: Pei-Chen Lo
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/56615651600627638936

博士 === 國立交通大學 === 電機與控制工程系所 === 96 === This dissertation reports the effects of Zen meditation on cardiovascular system and CNS electrophysiological behaviors. In the aspect of cardiovascular study, we evaluated the effects of meditation on cardiovascular system based on four parameters derived from blood pressure wave (BPW) that included the rising slope, normalized height of T wave, normalized height of V3 valley, and normalized height of D wave. The results showed that Zen meditation could lead to better heart ejection ability and aorta compliance, better arterial elasticity and aortic valve function, as well as the decreasing peripheral resistance of blood vessels. The observation allows us to infer that Zen meditation effectively improves functional characteristics of the cardiovascular system. To investigate the common experience of meditation practitioners - perception of inner light during meditation, we designed the flash visual evoked potentials (F-VEPs) experiments. Flash stimuli were applied before, during and after meditation- / relaxation-session in experimental / control subjects. Our results show that amplitudes of late latency components N3-P3 and P3-N4 at Oz decrease during meditation in the experimental group, whereas they increase in the control group. Both Cz and Fz amplitudes increase during meditation, yet decrease during relaxation for the control group. The latencies of some components increase under relaxation in control group, yet little variation (except P2) is observed in the meditators. According to our findings, Zen meditation induces particular effects on the visual nervous system and cortex that are distinguishable from those observed for normal relaxation. In chapter 4, we report our preliminary results of investigating the spatial focalization of Zen-meditation EEG (electroencephalograph) in alpha band (8-13 Hz). For comparison, the study involved two groups of subjects, practitioners (experimental group) and non-practitioners (control group). Wavelet analysis was applied to multi-channel EEG signals to extract the alpha rhythm. Normalized alpha-power vectors were classified by Fuzzy C-means based algorithm to explore various brain spatial characteristics. Number of clusters was determined by correlation coefficients of the membership-value vectors of each cluster center. Our results show that, in the experimental group, the incidence of frontal alpha activity varies in accordance with the meditation stage. And the results demonstrated three different spatiotemporal modules consisting with three distinctive meditation stages normally recognized by meditation practitioners. The parietal alpha activity in two groups decreased in different ways. Particularly, monotonic decline was observed in the control group. The phenomenon might imply various mechanisms employed by meditation and relaxation in modulating parietal alpha. In the research of visual perception under meditation based on alpha-dependent F-VEPs, we designed a strategy to record the F-VEPs under the consistent condition of background EEG – the emergence of dominant frontal alpha activity. According our preliminary results, the frontal alpha rhythms were more active during meditation. This event was thus used as the reference of meditation stage to trigger the flash stimuli. Based on the experimental protocol proposed, considerable differences between experimental and control groups were observed. In sum, amplitudes of P1-N2 and N2-P2 on Cz and Fz increased significantly during meditation, contrary to the F-VEPs of control group at rest. We thus suggest that Zen meditation results in acute response on primary visual cortex and the associated parts.