A meditation on the brain’s duality: the influence of meditation on the brain and the mind

The practice of meditation is concerned with eliminating duality (the separation of body and mind) and instead strives for a state in which the body and mind work together as one system (1). The brain can be viewed as a dualist system: it is a physical component of the body, yet gives rise to an abstract component, the mind. Drawing from discussions in class, I would argue that because the mind arises from the physical workings of the brain, it is often influenced by the various processes in the physical structure even though the mind likes to think of itself as being a component beyond the influence of the neurophysiologic processes of the brain. Thus the noise in the mind, its everyday commentary on what is going on around, and in relation to, us, might be a function of the mind’s internal processing of experience combined with the unconscious workings of the brain (unconscious in that they arise from the brain, not in a process open to the mind’s experience of itself).

From this viewpoint, the way to silence the mind, the goal of meditation, temporarily requires both relaxing the mind, as well as the brain itself. Since anyone who successfully meditates can experience the quieting of the mind, the influence of meditation on the mind is tangibly realized. However, there is still much to be learned about how meditation actually affects the brain, and perhaps how those effects then translate into influences on the mind. I would like to touch on only the surface of this broad and interesting subject by exploring the effects of meditation on a person’s perception of pain and positive thoughts by both the mind and the brain. I will begin by looking at pain perception in a 2006 study by Orme-Johnson and colleagues (2).

The study involved a group of long-term meditators and a control group whose brain activity was viewed (using functional magnetic resonance imaging) while experiencing pain induced by placing their fingers in hot water. The procedure was repeated again after the control group had been taught to meditate for five months. After each testing, the subjects rated their pain on a Pain Visual Analog Scale, a way to quantify pain experienced by the mind. Before the controls were taught to meditate, both they and the meditators showed the same ratings of pain on the Pain Visual Analog Scale, but brain scans showed as much as 50 percent less cerebral blood flow (which equates to activity). After only 5 months of meditation, controls showed the same response in brain scans as those people who had been meditating for many years.

These results suggest that meditation affects how the brain perceives pain by minimizing pain sensation input to the brain, but has no effect on how the mind perceives pain since the Visual Analog Scale tests of meditators and nonmediators alike claimed that they experienced the same degree of pain. The fact that the magnitude of pain perceived by the mind is the same whether the brain is experiencing a greater or lesser amount of pain from the same stimulus suggests that the pathway of pain is not first the experience in the brain, and then the output to the mind; rather it appears that the mind is getting its input both from the brain and somewhere else, perhaps at the sight of pain sensory input. Whatever the other input is, it appears that meditation has no effect on its influence over the mind.

It should be noted that the pain-infliction tests were not done while the subjects were meditating (2), suggesting that the differences in neural activity seen in the brain scans of meditators versus nonmeditators represent permanent changes in the brain. This permanence of change in the brain due to meditation has also been reported by others (3). It seems to be well accepted that repeating a certain thought process or pattern of activity in the brain makes it more likely for that process or activity to take place again in the future (4). Thus, habitually practicing meditation should lead to almost permanent changes in the brain’s circuitry.

One area of the brain that is noticeably influenced by such changes is the left prefrontal cortex, which has been seen to increase in thickness with the regular practice of meditation (3, 5, 6) and shows increased activity in brain scans taken on people as they meditate (6). The prefrontal cortex is associated with the ability to experience emotions (7). The left prefrontal cortex appears to be associated with positive emotions, while the right is more connected with negative emotional response. It is proposed that the left prefrontal cortex can minimize one’s emotional reaction to unpleasant situations and can more rapidly shut down a negative response once it has begun (7).

The thickening of the left prefrontal cortex as a result of meditation practices, suggests that meditation can change one’s emotional experience of life. It is reasonable to extend this benefit of meditation to a practical application: the treatment of disorders that negatively affect one’s emotional experience of life, such as depression. People who suffer from depression have much lower brain activity in the prefrontal cortex and the severity of depression is frequently linked to the degree to which brain activity is reduced in the prefrontal cortex (8). Interestingly, research suggests that increases in brain thickness are proportionally related to the amount of time in their life that a person has been meditating (5). Using brain thickness as an indication of brain activity (5), a logical conclusion of these discoveries is that people who have been meditating for many years should not be prone to depression.

Comparing the effects of meditation on pain perception and emotional perception is interesting because on the one hand, meditation decreases activity in the brain for a given process, pain perception, and on the other hand, it increases activity in the brain for a different process, emotional experience. For each case, the influence of meditation is present even if the activity is not taking place at the moment when the stimulus input is received. While meditation causes definite changes in brain structure and function, it is still unclear how much those changes influence the mind or whether the mind is influenced by meditation through some other means not measurable by brain activity. Perhaps the meditation’s effect on the mind is an emergent property of certain circuitry patterns in the brain not localized to one region, or perhaps meditation affects the internal workings of the mind itself, rather than affecting the mind by changing the brain from which the mind arises. Whatever the case, more research into meditation with respect to its influence on the brain and the mind is necessary to clarify both how meditation influences a person’s mental reality, their mind, and the physical organ from which the mind derives, the brain.

References:

1 Buddhist Meditation: Meditation in Buddhism. <http://www.experiencefestival.com/a/BuddhistMeditation/id/52700>.

2 Orme-Johnson, DW, Schneider, RH, Son, YD, Nidich, S, Cho, Z. 2006. Neuroimaging of meditation’s effects on brain reactivity to pain. Neuroreport 17(12): 1359-1363.

3 Kaufman, Marc. 2005. Meditation Gives Brain a Charge, Study Finds. Washington Post. <http://www.washingtonpost.com/wp-dyn/articles/A43006-2005Jan2.html>.

4 Siegel, Daniel J. The Developing Mind: How Relationships and the Brain Interact to Shape Who We Are. The Guilford Press: New York, 1999.

5 Cromie, WJ. Meditation found to increase brain size. 2006. Physorg.com Harvard University. <http://www.physorg.com/news10312.html>.

6 Wijesiri, Lional. Meditation’s Effect on the Brain. 2005. Maithri.com Ceylon Daily News. <http://www.maithri.com/links/articles/meditation_effect_brain.htm>.

7 Davidson, RJ. Understanding Positive and Negative Emotion. 2000. The Science of Emotion: Davidson (Library of Congress). <http://www.loc.gov/loc/brain/emotion/Davidson.html>.

8 Beauregard, M. Parts of the Brain that Slow Down or Speed up in Depression. The Brain from Top to Bottom. <http://thebrain.mcgill.ca/flash/i/i_08/i_08_cr/i_08_cr_dep/i_08_cr_dep.html>.