Dimensionality of multichannel EEG (Omega Complexity) during meditation in five traditions

During meditation, the brain shows more independent processes than during ordinary rest. EEG recordings from experienced meditators in five traditions (Tibetan Buddhist, Qigong, Shaja Yoga, Ananda Marga Yoga, and Zen) were analyzed using Omega Complexity, a measure of how many independent processes generate the brain's electrical activity. Omega Complexity was higher during meditation than during resting in all five groups, with statistically significant increases for Tibetan Buddhists, Ananda Marga Yoga, and Zen. The subjectively pleasant feelings during meditation appear to accompany a brain state with more independent processes, not fewer.

Study at a glance

Abstract

IntroductionThe measure of complex dimensionality assesses the number of independent processes that generate an observed time series.ObjectivesTo investigate whether meditation exercises are associated with fewer or more independently active brain processes, and whether different meditation traditions show different results.AimsDoes brain electric complex dimensionality differ between the state of meditation and of task free resting in different meditation traditions?MethodsMultichannel EEG recordings (19 to 25 channels) from experienced meditators of five meditation traditions (13 Tibetan Buddhists, 15 Qigong, 14 Shaja Yoga, 14 Ananda Marga Yoga, and 15 Zen) were analyzed (bandpass 1.5–30 Hz) using ‘Omega Complexity’ that obtains a single value for a set of simultaneously recorded EEG time series from a given person (J. Wackermann, Acta Neurobiol Exp (Wars) 1996;56:197–208). Omega Complexity during meditation was compared to the mean of Omega Complexity during pre- and post-meditation resting.ResultsDuring meditation relative to resting (paired t tests), Omega Complexity was higher in all five traditions, significant for Tibetan Buddhists (p = 0.01), Ananda Marga Yoga (p = 0.007) and Zen (p = 0.0003).ConclusionThe subjectively experienced agreeable feelings during meditation apparently occur, across meditation traditions, during a brain functional state that is characterized by an increase of independent brain processes compared to task free resting.