Yogic Control of Thoughts
Brain proposes and body disposes. That is how our body functions are perceived to be controlled by brain through a network of nerves that reach out to different organs. But many lower animals like single-celled Amoeba or bacteria have no brain and yet carry out all activities and respond to stimuli as efficiently as higher animals do. Intelligence, it appears is not confined to brain only but seems to be permeated in the whole body and in each cell. We may call it mind that every living being, even bacteria and viruses possess. On the other hand, a well-organized physical brain is a feature found only in higher animals, particularly vertebrates.
Brain is a highly complex organ, difficult to explore and experiment with but still physical. On the contrary mind is subtle and mysterious and spirit an unfathomable enigma. Brain, which is only 2% of our body weight is composed of about 15 billion nerve cells, each one of them connected to 20,000 others. That makes human brain’s capacity to process information to almost unlimited. Also, neurosecretory cells produce specific chemical messengers in response to thoughts arising in the brain. These specialized chemicals carry brain’s messages to different parts of body. Brain does not tolerate surgery because its tissues cannot regenerate. Most of the earlier studies on brain have, therefore, been rather indirect and superficial. But some recent techniques like MRI (Magnetic Resonance Imaging) and PET scan (Positron Emission Tomography) have revealed some hitherto unknown and mysterious activities of even deep-seated parts of brain that were so far mysterious to us.
The Emotional Brain
Two insignificant looking areas of brain, namely, Limbic System and Hypothalamus have now been found to control our hedonic feelings like pain, pleasure, anger, depression, anxiety, aggression, fear, sexual urge etc. we also know that emotional vicissitudes are the prime causes of organ malfunctions and diseases. It is therefore very important to understand how the thought patterns affect brain and eventually channelise into the body. Thoughts generally emerge in the large frontal lobes of brain, left side of which is concerned with thoughts related with planning, language, math skills, science and logic, while the right side deals with music, dance, art, sculpture, fantasy and perception. Thoughts appearing in frontal lobes immediately translate into chemical messages secreted by the neurosecretory cells.
The Limbic System
Seated deep in the temporal lobes is the limbic system, a small but important area that controls our day-to-day behavior and interaction with others. Stimulation of a group of cells in this region called septum pellucidum gives immense pleasure. Yogis by constant meditation somehow learn to stimulate this area and thereby derive constant bliss while sitting in meditation for hours. It can also be stimulated by planting electrodes. Another organ called Amygdala is associated with aggression, fearlessness and excitement. People having an aggressive disposition; apparently carry an overactive amygdala in their heads.
Attentiveness, learning, consciousness and memory are all controlled by a small cluster of cells called hippocampus, which is highly sensitive to alcohol. That is the reason a couple of drinks knocks out one’s attentiveness, memory and normal behavior. Nuclei of limbic system can also be stimulated by mild electric current, neurotransmitters, hormones like estrogen and testosterone, drugs, alcohol etc. to instantly alter the behavior of the subjects.
A stimulated limbic system transmits its messages to the corresponding areas of hypothalamus, which is a small but mighty area that connects mind with body and maintains body rhythms. Anterior part of hypothalamus contains sleep centers. Preoptic nuclei are related with sexual activity which is stimulated by sex hormones like estrogen and testosterone produced by gonads. Green (1954) stimulated this area by planting electrodes in monkeys and elicited a heightened sexual urge in them. Similarly, Olds (1953) of Montreal University implanted electrodes in pleasure centers of posterior hypothalamus and in septum pellucidum of rats. A mild current could be passed by pressing a lever. Rats quickly learned to stimulate this area by pressing the lever and some of them pressed it 5000 times in one hour. Posterior hypothalamus has centers for fighting, rage and aggression, while lateral hypothalamus possesses feeding centers. A tumor in this region can alter the corresponding behavior completely. When satiety centers in ventromedian hypothalamus of rats are destroyed by lesions, they were found to continue eating till they died of excessive eating.
Chemistry of thoughts
When a thought appears in the frontal lobes, it stimulates neurosecretory cells to release a specific neurotransmitter, a chemical that is capable of stimulating a specific center in the limbic system. A neurochemical produced by the negative thought will be entirely different from the one induced by a positive thought. Hundreds of these specialized chemical messengers are constantly secreted in our brain in response to a variety of thoughts appearing in the frontal lobes. Our brain possesses this amazing capacity to convert a thought, which is abstract into a chemical that is matter. As all our body activities are regulated by the complex biochemical processes, this is brain’s way to influence our body functions by producing thoughts in response to external stimuli.
Let us understand the whole psychosomatic mechanism of brain function by an example. If a robber attacks a group of persons, the thoughts originating in response to the attack will be different in each individual. Thoughts in a brave man’s brain will be very different from those in a coward and hence the neurochemicals secreted in frontal lobes will also be different.
In a brave man’s brain they will stimulate amygdala in the limbic system, which is associated with aggression and fearlessness whereas in a coward’s brain this center will be inhibited. An excited amygdala will stimulate the posterior and lateral hypothalamus (associated with aggression), which in turn will stimulate sympathetic part of the autonomic nervous system. Such a person will enter in a state known as “Fight or flight” syndrome, in which heart beat, blood pressure and respiration will go up, face will become red, eyes brighten up, sweating stimulated and the person will fight the robber.
On the other hand, in the case of coward, the chain of chemicals will stimulate the parasympathetic system, which is antagonistic to the sympathetic one. Consequently, the person will undergo depression and will probably faint or freeze. Such effects are normally momentary and disappear within a few hours. However, thoughts keep appearing ceaselessly in brain. Brain is never free from thoughts, not even in sleep. Therefore, the chain of biochemical stimulation of limbic system, hypothalamus, autonomic nervous system and endocrine glands also goes on continuously.
Negative thoughts if persistent will knock the body’s physiology out of balance. Such persons will eventually develop problems of organ malfunction and opportunistic diseases. No amount of medication can eradicate this kind of psychosomatic disbalance. Only a remedy at the thought level can bring about the desired biochemical homeostatic balance in body.
It is human nature to entertain negative thoughts like jealousy, malice, criticizing others etc., which always gain a silent entry in our minds but refuse to leave easily. We magnify them by identifying with them and entertaining them. On the other hand positive thoughts are benign and have to be introduced by effort. The best way to purify the mind-body biochemical chain is to be conscious of all thoughts entering our mind and firmly reject the negative ones. This has to be developed gradually as a habit, preferably through meditation. Meditation is the ultimate remedy to free mind of negative influences.
In transcendental form of meditation, with eyes closed, we try to make the mind thoughtless by constantly removing all thoughts that try to enter it silently. If practiced for about 20 minutes, the mind becomes blank and a lot of harmful neurochemicals are not released during this period. The stressed organs get much-required relief and body has time to carry out repairs.
A rejuvenated brain becomes more receptive to positive thoughts. As you proceed with your practice, lesser and lesser negative thoughts will enter mind and gradually the cycle of mind-body biochemistry will get modified and balance restored. Happiness, after all, is hidden inside us, within our minds and not in outside world. We must return back again and again to explore our minds and find it.