Zazen meditation and no-task resting EEG compared with LORETA intracortical source localization

Abstract

Meditation is a self-induced and willfully initiated practice that alters the state of consciousness. The meditation practice of Zazen, like many other meditation practices, aims at disregarding intrusive thoughts while controlling body posture. It is an open monitoring meditation characterized by detached moment-to-moment awareness and reduced conceptual thinking and self-reference. Which brain areas differ in electric activity during Zazen compared to task-free resting? Since scalp electroencephalography (EEG) waveforms are reference-dependent, conclusions about the localization of active brain areas are ambiguous. Computing intracerebral source models from the scalp EEG data solves this problem. In the present study we applied source modeling using low resolution brain electromagnetic tomography (LORETA) to 58-channel scalp EEG data recorded from 15 experienced Zen meditators during Zazen and no-task resting. Zazen compared to no-task resting showed increased alpha-1 and alpha-2 frequency activity in an exclusively right-lateralized cluster extending from prefrontal areas including the insula to parts of the somatosensory and motor cortices and temporal areas. Zazen also showed decreased alpha and beta-2 activity in the left angular gyrus and decreased beta-1 and beta-2 activity in a large bilateral posterior cluster comprising the visual cortex, the posterior cingulate cortex and the parietal cortex. The results include parts of the default mode network and suggest enhanced automatic memory and emotion processing, reduced conceptual thinking and self-reference on a less judgmental, i.e., more detached moment-to-moment basis during Zazen compared to no-task resting. Computing intracerebral source models from the scalp EEG data solves this problem. In the present study we applied source modeling using low resolution brain electromagnetic tomography (LORETA) to 58-channel scalp EEG data recorded from 15 experienced Zen meditators during Zazen and no-task resting. Zazen compared to no-task resting showed increased alpha-1 and alpha-2 frequency activity in an exclusively right-lateralized cluster extending from prefrontal areas including the insula to parts of the somatosensory and motor cortices and temporal areas. Zazen also showed decreased alpha and beta-2 activity in the left angular gyrus and decreased beta-1 and beta-2 activity in a large bilateral posterior cluster comprising the visual cortex, the posterior cingulate cortex and the parietal cortex. The results include parts of the default mode network and suggest enhanced automatic memory and emotion processing, reduced conceptual thinking and self-reference on a less judgmental, i.e., more detached moment-to-moment basis during Zazen compared to no-task resting.

Spectral power and functional connectivity changes during mindfulness meditation with eyes open: A magnetoencephalography (MEG) study in long-term meditators

“…It is also noteworthy that no significant changes in any of the other frequency bands were discovered over the course of the meditation, either within-or between-groups, which is in contrast to a number of previous studies which have utilized eyes-closed meditation techniques (Aftanas & Golocheikine, 2001, 2002, 2003Cahn & Polich, 2006;Faber et al, 2014;Huang & Lo, 2009;Lagopoulos et al, 2009). In particular the absence of changes related to the gamma frequency band is different from studies using eyes closed meditation.…”

“…Consistent with the eyes-closed meditation literature, an early EEG study by Murata et al (1994) involving 20 Zen monks and 10 control participants reported that frontal theta power was significantly increased 25 minutes into eyes-open meditation in comparison to the start of meditation, an increase that was only observed in the monks. In a more recent EEG study by Faber et al (2014), changes in brain activity were investigated in 15 experienced Zen practitioners whilst they completed 60 minutes of eyes-open meditation versus no-task resting, with the data analysed using low resolution brain electromagnetic tomography (LORETA). In comparison to the rest condition, alpha-1 (8.5-10 Hz) and alpha-2 (10.5-12 Hz) activity were found to be significantly increased in a right-lateralized cluster which included prefrontal areas, insula, somatosensory, motor cortices and temporal areas.…”

Meditation Experiences, Self, and Boundaries of Consciousness

“…Not only does meditation facilitate the ability to remain calm and in control of emotions during stressful situations, it also helps one to gain a better understanding of one's 'self' or presence in reality [52]. Meditation may be thought of as a voluntary practice altering state of mind in the direction of pure consciousness [53]. The process of meditation activates the brain's prefrontal cortex (PFC) increasing levels of free glutamate in the brain [50,54].…”

“…EEGs have shown that the 'breath of fire' technique that requires a moderate amount of conscious control, results in increased heart rate and decreases the connection between heart rate and breathing [63], that again are different experiences from pure consciousness. Zazen practitioners focus on attention on detachment from the thinking process to minimize thoughts, which has been shown to "enhance automatic memory, emotion processing, reduce conceptual thinking, and reduce judgmental self-referencing," along with "health, well-being and happiness" [53,64].…”

“…Meditation practice can alter a person's state of consciousness and the DMN activity may change via PFC activation [54,49,53,55]. PFC activation affects attention, emotions, feelings of fear and pain, feelings of calmness and relaxation, hormonal activity, and physiological changes in blood pressure and vascular resistance because of: 1) increased levels of free glutamate and beta-endorphins, 2) cardio-respiratory synchronization, and 3) regulation of the central nervous system and amygdala, among others.…”