Spect Reveals Yoga’s Effects, Potential
According to Megan McDonough, CNMT, a nuclear medicine technologist and yoga teacher from Hardwick, Mass., historic evidence suggests the genesis of yogic roots existed as far back as five million years ago. McDonough, who speaks internationally at imaging conferences and provides yoga training sessions for diagnostic imaging groups, said the fully developed philosophical school of yoga began as a system of mental, physical and spiritual exercises in approximately 500 B.C. by the physician and sage Patanjali.
He formalized the tradition into a science involving ethical restrain, self-discipline, mental focus, physical exercise and meditation.
Yoga is defined as a “simplification of consciousness” that decreases the extraneous matter that causes pain and suffering and leaves clarity about the true nature of reality. There are different branches of yoga, McDonough said, based on the knowledge that each person is unique and will respond differently to a given practice. The most familiar branch is Hatha-Yoga, which is based on the premise that the physical body can be purified through postures leading to self-transformation. It can be used as a spiritual practice and to strengthen the body, clear the mind, increase flexibility and relieve stress and tension. Hatha-Yoga uses breathing to settle the body and focus the mind. It is easy to notice the effect breathing has on one’s own state of mind. Changing that state requires an awareness of the current breathing pattern and then application of an antidote.
Medical practitioners recognize the role of stress as a major contributor to disease, and many believe a simple stress management technique such as yoga/meditation could be constructively applied in the clinical setting.
Medical uses of yoga
All sensory input creates a mental activity located in the brain that can be measured by such imaging modalities as SPECT (single photon emission computed tomography) and MR. Imaging test results have shown health and medical benefits derived from meditation and yoga. At the University of Pennsylvania, a new department has been opened, neurotheology, that encompasses the ground-breaking work of the SPECT machine, which can record brain activity during meditation and prayer.
In Penn’s department of neurotheology, Andrew Newberg, MD, conducted a SPECT study on Tibetan Buddhist monks and Franciscan nuns. When each study subject’s focus was at maximum, he or she would tug on a piece of rope connected to the SPECT technologist, who would then inject radioactive tracer into an intravenous line in the subject. The SPECT image tracked the tracer in the brain’s blood flow, highlighting neuronal activity. The pictures clearly showed that specific, previously active portions of the brain became quiet, and vice versa. This revealed which parts of the brain were stimulated or pacified during different meditative practices. This was enough evidence to support future research.
Results showed that meditation is associated with increased blood flow in the frontal lobes, which correlates with decreased activity in the posterior parietal lobes. Decreases in blood flow in the left superior parietal lobe and increases in the left prefrontal cortex suggest the two areas work together to create a sense of space. This finding corroborates prior studies. There was also an increase in blood flow to the sensorimotor cortex, which contradicted Dr. Newberg’s hypothesis that meditation dampens the perception of distracting external stimuli. Increased activity was also found in the thalamus and midbrain.
During meditation, areas of the brain that control logic, reason, association and orientation are “knocked out,” creating a dream-like stage similar to that of sleep. This is known as a “higher state of consciousness.” The beneficial effects of meditation, lower blood pressure, sense of deep rest, and constructive immune response are thought to be due to the activity of cholinergic neurons during this state.
Other studies have measured the different physiological changes that meditation and related practices are associated with, including those related to blood pressure, heart rate and changes in cortisol levels. Because there are different types of meditation, it is important to evaluate and compare changes associated with different types of meditation to help elucidate the physiological mechanisms underlying the effects of meditation (Newberg, et al., 2001). Meditation provides the energy sources needed for full cognitive functioning. The stress-related, hypothalamus-pituitary axis is linked to the hippocampus, which undergoes increased activation during meditation.
Studies show that the hippocampus of patients with depression is smaller than usual, which is considered related to increased stress-induced cortical levels. Thoughts have been shown to have a corresponding reaction at the physiological level. For instance, anger raises the heart rate and blood pressure, which can then lead to heart attack.
Thomas Zoega Ramsoy, a neuropsychologist at the Lions Collegium in Copenhagen, said, “Looking for effects or benefits of yoga in the brain might lead to a problem of interpretation, since we are only dealing with correlations. However, I have noticed that different kinds of yoga and meditation might have beneficial effects on many abnormal states such as epilepsy, depression and anxiety.”
At the State University Hospital in Copenhagen, Hans Lou and Troels Kjaer from the Kennedy Institute have taken PET scans of the brain during meditative deep-relaxation. Although researchers at the Scandinavian Meditation School had previously collaborated to examine the effects of yoga on blood pressure and other physiology, actually measuring consciousness and how the brain functions by conscious control of awareness, was new.
During the PET scan, the brain’s activity was measured by electroencephalography (EEG), which showed that the subjects were in a meditative state during the entire deep yoga. PET scans were also taken of a normal waking state and also showing in which areas of the brain the activity had increased during yoga. The scans show that the subjects were not drowsy or unconscious during the relaxation. The pictures showed specific areas in the brain being activated sequentially based on where the subject was in yoga. Researchers deduced that what happens in the brain during yoga, or where it happens, is not a matter of chance-concentration is a spontaneous state, which comes of its own accord when a method is used that removes whatever is hindering it (Nilsson, 2001). Lou and Kjaer said, “It proves that the 1.5kg (brain mass) with the unknown content can control its own activity in an astonishingly precise manner; holistically, this indicates that the soul and body act in unity.”
fMRI and meditation
fMRI has also been used to study the brain during meditation, and the fMRI signal has been seen to vary with measured physiological changes (Lazar, et al., 2000). The signal increases were regionally specific, rather than global in nature. The foci activation identified in this study were consistent with those described by the PET study of Lou, et al., which did not find changes in global cerebral blood flow (Lazar, et al., 2000). Elucidation of the biological basis of meditation will shed new light on cognitive and emotional brain processing systems elicited by the relaxation response, and hopefully lead to greater acceptance of the relaxation response as a complement to other medical treatments (Lazar, et al., 2000).
The work of Alarik Arenander, a neuroscientist, educator, national lecturer and leading researcher, into the neurobiology of brain development has helped establish the field of neuroscience as a leading area for exploring human potentiality. Dr. Arenander has conducted pioneering research at the University of California at Los Angeles, Penn State University at Hershey, University of Wisconsin at Madison, and the Maharishi University of Management (MUM) in Fairfield, Iowa. Since 1999, he has been the director of the Brain Research Institute at MUM’s Institute of Science, Technology and Public Policy. His research focuses primarily on brain development, on the relationship of brain and consciousness, and the role of the environment and experience on developmental processes.
Dr. Arenander said, “Not all neuroimaging techniques are alike, so one will expect different findings from different technique studies. Each technique has good and bad points, advantages and disadvantages, strengths and weaknesses.” Dr. Arenander thinks the PET work is the best of the studies, because it is easier to quantify, and the research designs have been better.
“The imaging of meditation is just now beginning,” he said. “It is a little like the wild, wild west lots of new exploration, minimal rules and lots of opinions.”
He continued, “Since the brain structure is always quite fluid and plastic, each experience gives a direction to change. In turn, the brain will automatically determine our behavior.”
For example, violin lessons help you learn the violin, but do not impact your social skills. Also, he said, input of specific, fragmented, superficial content will have a different effect than experience, which is more holistic, integrated and deeply connected to the individual’s inner values of mind and consciousness. Since diversity dominates at present, Dr. Arenander believes, we can only hold to the scientific method and look for the underlying unifying principles that mediation and yoga offer to our lives.
Dr. Arenander’s research on meditation is trying to bring some sense of order or structure to a very fluid territory. “Progress demands that we find the basic principles by which humans can transcend, contact their inner source of consciousness and health, and explore and develop the full potential of human experience,” he said.
