Zen Meditation

Zen meditation has been practiced for thousands of years, and it is widely believed that the practice has mental and physical health benefits. Recently, the scientific community has become interested in Zen meditation and has begun to study its effects.

A common finding in several studies is an increase in activity of both alpha and theta waves in the frontal region of the brain during meditation (Takahashi et.al. Murata et. al.).  Alpha waves are associated with “relaxed wakefulness“ with the eyes closed and usually cease upon eye-opening. Alpha blocking is associated with visual perception. Alpha waves tend to synchronize during inwardly focused attention and desynchronize during externally-focused attention. The alpha waves typical of meditation are slow and synchronized and are present even with the eyes open, suggesting internal awareness and decreased focus on the visual field. Experienced meditators sometimes report perceiving an “inner light.” Interestingly, during the perception of inner light while meditating with closed eyes, alpha activity ceased as it would upon eye-opening in non-meditators.
Another common finding is an increase in the normalized unit of high frequency power on the EEG, which indicates increases in parasympathetic activity, and a decrease in the normalized unit of low frequency power, which indicates decreased sympathetic activity (Lo and Wu, Takahashi et.al.).  The sympathetic nervous system is often called the “fight or flight” system while the Parasympathetic nervous system is often called the “rest and digest” system. Takahashi et.al. suggests that it is the increase in alpha activity that suppresses the sympathetic nervous system and that the increase in theta activity stimulates the parasympathetic system.
The level of training and experience in Zen meditation an individual has seems to be an important factor in the kind of brain activity present during meditation and possibly even when not meditating. Murata et. al. shows that more experienced meditators show more theta activity in the frontal region of the brain when meditating than do less experienced meditators and that the alpha activity in these individuals increases in early meditation but does not continue to increase in later meditation as it does in those with less experience. Lo, Huang, and Chang show that in very experienced meditators high frequency beta waves occur in rare bursts.
Personality may also be related to an individual’s ability to successfully induce these changes through meditation. Takahashi et.al. studied the relationship between personality traits and meditation induced brainwaves. Subjects who had a high novelty seeking score on the personality test showed a greater increase in alpha activity during meditation.  A high novelty seeking score is also associated with dopaminergic activity.  Dopamine-releasing drugs have been shown to increase slow alpha power and inhibit the sympathetic nervous system and meditation has been shown to increase dopamenergic activity. Additionally, a high harm avoidance score correlates with an increase in theta activity through meditation. A high harm avoidance score indicates an inhibitory response to aversive stimuli and is associated with serotonin receptor sensitivity. Serotonin activation has been shown to increase theta activity (Takahashi et. al.).
Zen meditation has effects on behavior as well. Grant and Rainville show that highly trained Zen meditators experience a decrease in pain intensity and in pain unpleasantness when meditating or “attending mindfully.” The suppression of the sympathetic nervous system during meditation might help explain this phenomenon. Pain elicits a norepinephrine-like response in most people and the sympathetic nervous system is responsible for the release of norepinephrine. Another explanation is that since meditation is marked by a blocking of external attention (Takahashi et.al.), the painful stimuli was merely not the focus of the meditators‘ attentions. The slowed respiratory rate during meditation was also proposed as a possible explanation (Grant and Rainville).
Interestingly, the meditators had a significantly higher pain tolerance than did the non-meditators even when not engaging in meditation. This finding suggests that the long-term practice of Zen meditation may in fact permanently alter the brain. Pagnoni, Cekic, and Guo suggest that “regular practice of Zen meditation enhances the capacity for voluntary regulation of spontaneous mental activity.” Also evidence that meditation might have a lasting impact on the brain is the study conducted by Murata et. al. showing that Zen priests have increased theta rhythms in the frontal brain area even when not meditating.
Zen masters appear to not only have the ability to alter their own bodies and minds, but others’ as well. Lo, Huang, and Chang showed that while resting with eyes closed, several meditators began alpha blocking upon receiving a blessing from a Zen master. The subjects did not know that they were receiving a blessing and the Zen master was in a different room than the subjects. Yu, Tsai, and Hwang showed that meditation from a Zen master can inhibit tumor growth. Prostate cancer cells were places in 16 plates. Eight were meditated over by a Zen master. He placed his right hand over each for a minute. The other eight were not meditated upon. The cells he meditated over showed significantly less growth and three times as much PAcP. PAcP is important for regulating prostate cell growth.

Works Cited:

Grant, Joshua A.; Rainville, Pierre. “Pain Sensitivity and Analgesic Effects of Mindful States in Zen Meditators: A Cross Sectional Study.” Psychosomatic Medicine 71 (2009).

                Lo, Pei-Chen; Huang, Ming-Liang; Chang, Kang-Ming. “EEG Alpha Blocking Correlated with Perception of Inner Light During Zen Meditation.” The American Journal of Chinese medicine. Vol. 31 No. 4 (2003).

                Lo, Pei Chen; Wu, Shr-Da. “Inward attention meditation increases parasympathetic activity: a study based on heart rate variability. Biomedical research 29 (2008).

Murata, Tetsuhito et. al. “Quantitative EEG Study on Zen Meditation (Zazen).” The Japanese Journal of Psychiatry and Neurology, Vol. 48 No. 4. (1994).

Pagnoni, Giuseppe; Cekic, Milos; Guo, Ying. “Thinking About not Thinking: Neural Correlates of Conceptual Processing during Zen Meditation.” PLoS ONE 3(9): e3083 doi:10.1371/journal.pone.0003083

Takahashi, Tetsuya et al. “Changes in EEG and autonomic nervous activity during meditation and their association with personality traits.” International Journal of Psychophysiology 55 (2005).

Yu, Tiing; Tsai, Hui Ling; Hwang, Ming Liang. “Suppressing Tumor Progression of In Vitro Prostrate Cancer Cells by Emitted Psychosomatic Power through Zen Meditation.” The American Journal of Chinese Medicine. Vol. 31 No. 3 (2003).