Different Types of Meditation Techniques Affect Neural Activity Differently
By John M. de Castro, Ph.D.
“The picture we have is that mindfulness practice increases one’s ability to recruit higher order, pre-frontal cortex regions in order to down-regulate lower-order brain activity.” – Adrienne Taren
Meditation training has been shown to improve health and well-being. It has also been found to be effective for a large array of medical and psychiatric conditions, either stand-alone or in combination with more traditional therapies. As a result, meditation training has been called the third wave of therapies. One problem with understanding meditation effects is that there are, a wide variety of meditation techniques and it is not known which work best for improving different conditions.
There are a number of different types of meditation. Many can be characterized on a continuum with the degree and type of attentional focus. In focused attention meditation, the individual practices paying attention to a single meditation object, learns to filter out distracting stimuli, including thoughts, and learns to stay focused on the present moment, filtering out thoughts centered around the past or future. Transcendental meditation is a silent mantra-based focused meditation in which a word or phrase is repeated over and over again with the meditator focusing attention on the mantra. This is designed to evoke the experience of pure awareness. In open monitoring meditation, the individual opens up awareness to everything that’s being experienced regardless of its origin. These include bodily sensations, external stimuli, and even thoughts. The meditator just observes these thoughts and lets them arise and fall away without paying them any further attention. Loving Kindness Meditation is designed to develop kindness and compassion to oneself and others. The individual systematically pictures different individuals from self, to close friends, to enemies and wishes them happiness, well-being, safety, peace, and ease of well-being.
These techniques have common properties of restful attention on the present moment, but there are large differences. These differences are likely to produce different effects on the practitioner. One way to distinguish between the effects of these different meditation techniques is to observe the effects of each technique on the brain’s activity. This can be measured by recording the electroencephalogram (EEG). The brain produces rhythmic electrical activity that can be recorded from the scalp. It is usually separated into frequency bands. Delta activity consists of oscillations in the 0.5-3 cycles per second band. Theta activity in the EEG consists of oscillations in the 4-7.5 cycles per second band. Alpha activity consists of oscillations in the 8-12 cycles per second band. Beta activity consists of oscillations in the 13-30 cycles per second band while Gamma activity occurs in the 30-100 cycles per second band.
In today’s Research News article “.” (See summary below or view the full text of the study at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5890111/ ), and colleagues review and summarize the published research literature on the effects of various meditation techniques on neural activity as measured with the electroencephalogram (EEG). They report that meditation practice, in general, is associated with increased brain oscillations and the greater the amount of practice the greater the increase in oscillations. This suggests that meditation practice, regardless of type, effects neural activity.
Activity in the Theta band of the EEG (4-7.5 hz.) differs with the type of meditation practiced. Both, focused and open monitoring meditation increase Theta oscillations in the anterior portions of the cerebral cortex. But, focused meditation also increases Theta activity in the posterior cortex. Theta activity is associated with positive emotional states and memory.
Activity in the Alpha band of the EEG (6-12 hz.) differs with the type of meditation practiced. Both, focused and open monitoring meditation increase Alpha oscillations in the posterior portions of the cerebral cortex. But, focused meditation also increases Alpha activity in the anterior cortex while open monitoring meditation decreases Alpha on the left side of the frontal cortex. Alpha activity is associated with relaxation and drowsiness.
Activity in the Gamma band of the EEG (6-12 hz.) increases in the frontal regions with all forms of meditation. This is sometimes known as fast wave activity and is associated with sensory and cognitive processing. There is conflicting evidence regarding the effects of meditation practice on the other oscillatory bands.
This research makes it clear that meditation practice increases the brains electrical activity and there appears to be differences in the oscillatory patterns produced by different meditation techniques. This may help in identifying the underlying processes responsible for the differing effects of these practices. But, the research is at a very early stage of development and much more work will be required to come to any firm conclusions.
So, it is clear that different types of meditation techniques affect neural activity differently.
“It was already known that during meditation brain wave activity increases in areas like alpha waves. These MRIs showed something more permanent: denser gray matter in specific regions like the hippocampus, which is crucial for learning and memory, as well as in other areas associated with self-awareness, compassion, and reflection.” – Deepak Chopra
CMCS – Center for Mindfulness and Contemplative Studies
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Lee, D. J., Kulubya, E., Goldin, P., Goodarzi, A., & Girgis, F. (2018). Review of the Neural Oscillations Underlying Meditation. Frontiers in Neuroscience, 12, 178. http://doi.org/10.3389/fnins.2018.00178
Objective: Meditation is one type of mental training that has been shown to produce many cognitive benefits. Meditation practice is associated with improvement in concentration and reduction of stress, depression, and anxiety symptoms. Furthermore, different forms of meditation training are now being used as interventions for a variety of psychological and somatic illnesses. These benefits are thought to occur as a result of neurophysiologic changes. The most commonly studied specific meditation practices are focused attention (FA), open-monitoring (OM), as well as transcendental meditation (TM), and loving-kindness (LK) meditation. In this review, we compare the neural oscillatory patterns during these forms of meditation.
Method: We performed a systematic review of neural oscillations during FA, OM, TM, and LK meditation practices, comparing meditators to meditation-naïve adults.
Results: FA, OM, TM, and LK meditation are associated with global increases in oscillatory activity in meditators compared to meditation-naïve adults, with larger changes occurring as the length of meditation training increases. While FA and OM are related to increases in anterior theta activity, only FA is associated with changes in posterior theta oscillations. Alpha activity increases in posterior brain regions during both FA and OM. In anterior regions, FA shows a bilateral increase in alpha power, while OM shows a decrease only in left-sided power. Gamma activity in these meditation practices is similar in frontal regions, but increases are variable in parietal and occipital regions.
Conclusions: The current literature suggests distinct differences in neural oscillatory activity among FA, OM, TM, and LK meditation practices. Further characterizing these oscillatory changes may better elucidate the cognitive and therapeutic effects of specific meditation practices, and potentially lead to the development of novel neuromodulation targets to take advantage of their benefits.