Over the past few years brain scientists have used magnetic resonance imaging to try to understand how the brain can change over time and how this relates to disease. While MRIs expose us to considerable electromagnetic radiation, the data that has come from the past decade of brain scan research is notable.
Such research finds, in fact, what was already known in ancient times – that yoga meditation or meditation in general, whether part of a hatha yoga system, prayer or otherwise – has the ability to reduce and even reverse the symptoms related to chronic fatigue and chronic pain.
But scientists want to know the mechanisms before they can accept the relationship between Yoga and pain and fatigue. It is not enough that millions of people have reported pain and fatigue reduction over thousands of years of the practice of yoga.
While doing MRI brain scans has not revealed the mechanism between meditation and the reduction of pain and fatigue, it has revealed one of the byproducts of each: the brain’s gray matter (or grey matter) with the brain.
What the heck is Gray Matter anyway?
Put simply, the gray matter of the brain is composed of brain and nerve cells (neurons) tightly bunched together and bound together with their axons and synapses. Furthermore, these neurons do not typically have the myelin sheaths that will surround other types of neurons.
Within the gray matter is where much of the action of the brain occurs. Gray matter is also thick with capillaries, which deliver nutrients to feed those important neurons of the brain.
Gray matter is different from white matter in that white matter contains more sparse populations of neurons. Those neurons will also typically have the myelin sheaths and will have longer axons – rendering them with greater reach through the body.
Thus we find the gray matter especially critical for the processes of the brain.
Cortical Gray Matter
In a healthy person, each of our brain regions – each cortex – will be thick with gray matter. Areas where gray matter is critical include the cerebral cortex, the cerebellum, the cuneal and precuneal cortices, the motor cortices and the somatosensory cortex among others.
Having normal levels of gray matter is critical to our brain’s proper functioning, which includes decision-making, executive cognitive functions, retaining memories and so on. They are also critical for the brain’s sensory and motor responses.
Gray matter and chronic pain and chronic fatigue
Why is this important? Because brain scan research has found that people with chronic pain and chronic fatigue will typically also have abnormal levels of gray matter among different cortices of the brain.
Chronic pain, for example, has been linked to a reduction of gray matter in the cerebral cortex. And chronic fatigue syndrome patients have been found to have less gray matter in prefrontal and occipital cortices of the brain.
Meanwhile, research has illustrated that insomnia is associated with less gray matter in the brain’s left orbitofrontal cortex.
Different types of chronic pain are related to gray matter abnormalities in different areas.
For example, one university study found that patients with chronic back pain have reduced gray matter in the postcentral gyrus, along with the left precuneus and bilateral cuneal cortex.
This study also found that upper back pain patients had gray matter abnormality in different locations of the brain – such as a reduction in the left precentral and left postcentral cortices.
And chronic migraine sufferers have also been found to have significant abnormalities in gray matter content.
All of these and other brain scan studies had a basic method: The researchers would do brain scans on a good number of people with the condition. Then they would compare these to brain scans done on a good number of people who were healthy. They would then calculate the differences in gray matter.
What this means is there is a growing database of what is considered normal gray matter within the brain’s regions. While there are individual differences between our gray matter, there are also great similarities in the amount of gray matter volume among healthy people.
This brings us to research specific to yoga meditation practice. Researchers from the Brain Imaging and Analysis Center at Duke University Medical Center tested seven hatha yoga meditation practitioners and seven people who did not have a history of hatha yoga or meditation. They were all between the ages of 18 and 55.
The researchers gave each of the subjects a battery of tests, including those on symptoms of depression, anxiety and mood states. They also tested cognition and of course, conducted MRI brain scans on each.
The yoga meditation practitioners had significantly greater gray matter volumes in a number of brain regions. These included the bilateral orbital frontal cortex, the right middle frontal and the left precentral region. The yoga meditation practitioners also had higher levels of gray matter among the cerebellum, the temporal cortices, the occipital cortex and the hippocampus.
One of the most important findings was the significant increase in gray matter among the prefrontal cortex regions of the yoga meditation practitioners. Other research has found this region of the brain is involved in decision making, reward-consequence, lifestyle evaluation, control and action coordination.
This region together with the cerebellum is also involved in executive functions related to coordinating our goals and objectives in life. The researchers mentioned that this indicated a link between yoga meditation and cognitive plasticity.
Cognitive plasticity in the brain means that the brain is responding to the self’s objectives, by altering the brain’s functions, size and general condition.
In no case did the researchers find those that did not practice yoga meditation had greater gray matter regions than those who did practice the yoga meditation.
To be fair, this study didn’t necessarily prove that yoga meditation increases gray matter per se. From a pure scientific method approach, there is always the possibility that those with greater gray matter just happen to choose hatha yoga meditation. This, however, would be an incredible coincidence, and thus unlikely.
Other research finds meditation increases gray matter
Gray matter content is increased with meditation. This is also confirmed by other research that has indeed found that hatha yoga and mindfulness meditation in general not only affect brainwave content within the brain, but also boost gray matter content within the brain.
Other research has in fact seen this type of ‘intervention’ effect – increasing gray matter. Researchers from India’s National Institute of Mental Health and Neurosciences studied seven elderly persons who added hatha yoga practice to their lives for six months. The research found significant increases in gray matter within the hippocampus of the test subjects.
Furthermore, researchers from the University of Illinois at Chicago investigated no less than 15 studies that examined yoga interventions and the brain. The researchers found that yoga practices significantly produced immediate and lasting changes within the brain:
“It was concluded that breathing, meditation, and posture-based yoga increased overall brain wave activity. Increases in gray matter along with increases in amygdala and frontal cortex activation were evident after a yoga intervention. Yoga practice may be an effective adjunctive treatment for a clinical and healthy aging population. Further research can examine the effects of specific branches of yoga on a designated clinical population.”
A review of a broader swath of research led by Dr. John de Castro from the Sam Houston State University also found that the associations of yoga practice with the brain were also similar to those found from mindfulness meditation as well as prayer. Dr. Castro concluded that both mindfulness and prayer had a foundation within the context of meditation.
The word yoga is derived from ancient Sanskrit which literally means ‘union with God.’ As we have investigated elsewhere, the understanding that our ultimate identity lies on the spiritual rather than the physical plane has been established repeatedly through scientific research.
Now we find that focusing upon spiritual practices indeed affects not just the mind, but the body in a real sense: Scientifically establishing the traditional healer’s assumption of the connection between the body, the mind and the spirit.
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Case Adams is a California Naturopath and a Board Certified Alternative Medicine Practitioner with a PhD in Natural Health Sciences, and diplomas in Homeopathy, Aromatherapy, Bach Flower Remedies, Blood Chemistry, Clinical Nutritional Counseling and Colon Hydrotherapy. He has authored 26 books on natural healing strategies.