禪坐組與一般控制組的腦電波Alpha波之非線性相依性的探討

Abstract

本篇論文以非線性動態系統的觀點，研究禪坐對於中樞神經系統的影響，並著重於腦電波中的Alpha波。首先利用連續時間小波轉換 (continuous-time wavelet transform) 來判斷Alpha波在各頻帶中的能量比例。接著藉由量化相似度指標(S)以及相位空間重建法發展出非線性相似性，另外利用傳統的線性理論進行相關性分析做為參考比較。我們選取了10位資深的禪定者 (實驗組)，與10位無禪定經驗者 (一般控制組)做進一步的研究。 本研究中所探討的腦區分為前腦(F)、後腦(P)、右腦(R)、左腦(L)、中腦(C)，而對實驗組而言分為三階段：閉眼放鬆 (stage R)、禪定 (stage M)、守禪心輪 (stage Z)。研究結果發現，實驗組在禪定和守禪心輪兩階段交互影響強度較閉眼放鬆高。對於控制組而言，實驗組也有較強的空間交互作用。

This thesis is aimed to investigate the effects of Chan meditation on brain electrophysiological behaviors from the viewpoint of nonlinear interdependence among regional neural networks. Particular emphasis is laid on the EEG (electroencephalograph) alpha rhythm. Continuous-time wavelet transform (CWT) was adopted to extract alpha rhythm. Nonlinear interdependent measurement based on quantification of similarity index S(X|Y), the influence of source signal Y on sink signal X, was applied to the nonlinear dynamical phase-space brain model reconstructed from multi-channel EEG. As a reference, coherence analysis based on linear assumption was applied to EEG time series to evaluate the spatially linear correlation among EEG channels. Experimental and control group involved respectively ten experienced Chan-Meditation practitioners and ten healthy control subjects within the same age range.

Nonlinear interdependence interaction among various cortical regions was explored for five regions of local neural networks, frontal (F), parietal (P), right-temporal (R), left-temporal (L) and central (C) regions. For the experimental group, the interaction was evaluated for the brain dynamics under three different stages, at rest (stage R, pre-meditation background recording), in Chan meditation (stage C) and the unique Chakra-focusing practice (stage C). This study on the experimental group reveals a significant finding of stronger interactions among local neural networks at stages M and Z compared with the result at stage R. The inter-group comparison demonstrates that Chan-meditation brain possesses better spatial interactions among various cortical regions than the resting brain of control group.