Western science for most of its history has considered the mind and body as separate entities, and it is only in the last 20 to 25 years that science has proven that notion to be false. If neurotransmitters, which were once believed to be exclusively brain information chemicals that control mood, are found in the body, and have been discovered to be manufactured by the immune system also, and neuropeptides that are secreted by the immune system and endocrine system have receptors in the brain, it becomes obvious that there is a two-way communication happening.
Candace Pert, PhD suggests that it is useful to think of these messenger chemicals as information substances that link the brain to the body and vice-versa. When we think of the mind, we think of the flow of information and emotion in a non-material sense, but mind can also be viewed as the communication network between the material body and the brain. Therefore, as Candace Pert says, we can acknowledge that mind and body are actually one, and that there is an intelligence to the system - it is not simply mechanical hardware, reflexes and electricity as was once believed. Mind or consciousness leads to manifestation in the body. According to Candace Pert, emotions are the neuropeptides and receptors that carry information that link the major systems of the body into "one unit that we can call the bodymind". In her words, "We can no longer think of the emotions as having less validity than physical, material substance, but instead must see them as cellular signals that are involved in the process of translating information into physical reality, literally transforming mind into matter. Emotions are at the nexus between matter and mind, going back and forth between the two and influencing both."
An example of this is when we are nervous we often feel butterflies in the stomach. We talk about "gut instincts". We have tons of neuropeptides and their receptors in the intestinal tract, so it isn't surprising that we often feel our emotions in our gut. And when our intestines are not functioning well and can't digest our food, we often feel short tempered, so the flow of information can go both ways. Another example is that controlled breathing is often used to reduce pain for women in labour. Women are taught how to alter their breathing on a conscious level, which in turn alters the quantities of endorphins released, which reduces the pain. The physical change of altering the breath, change the feeling of pain. Going the other way, if you vividly imagine slicing and then biting into a juicy lemon, you will probably find yourself salivating. Your thought created a physical response in your body. So, your physical body can change your thought or feeling, and your thought or feeling can change your physical body. And this all happens through peptides being released and binding to receptors as a consequence of your physical actions, your thoughts or your feelings.
Howard Hall in 1992 showed that the immune system, which is filled with peptides, could be trained at a conscious level through biofeedback techniques. This has huge implications for the major diseases. Studies have shown that cancer patients who controlled their anger or grief did not recover as well as those who expressed their feelings. This is not to say that it is the individual's fault that they got cancer. But, a cancer patient can learn to aid the immune system to fight the cancer by refusing to hold back on his/her feelings. Allowing oneself to feel ones feelings is important to keeping the peptides flowing freely and the psychosomatic system functioning effectively. Thinking happy thoughts that cover up repressed feelings is not helpful. So let out your anger, grief, frustration etc. in a constructive way, and jumpstart your immune system.
Candace Pert's book Molecules of Emotion: Why You Feel the Way You Feel is a fantastic mix of autobiography and explanation of the hard core science she was doing at Johns Hopkins, at the NIH, and at Georgetown University. Her research into the physiology of emotions is facinating, and the implications actually give some credibility to alternative therapies that use mind-body and/or spiritual techniques. Part of what I enjoyed so much about this book was how her own research forced her to open her own mind to ideas that typically would not even be entertained by a research scientist. I highly recommend the read.
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Pert, Candace PhD, Molecules of Emotion Scribner, New York, NY, 1997.
Hall, Howard R. et al. Voluntary modulation of neutrophil adhesiveness using a cyberphysiologic strategy International Journal of Neuroscience 63, 287-297, 1992.
Hall, Howard R. et al. Voluntary immunomodulation: A preliminary study International Journal of Neuroscience 63 (3-4), 275-285, 1992
Andrews, Vivian H et al. The effects of relaxation/imagery training on recurrent aphthous stomatitis: A preliminary study Psychosomatic Medicine 52, 526-535, 1990.