Summary
After a pleasurable or a painful experience, the brain builds up conditioned neuronal circuits (saṅkhāras) for repeating or avoiding the experience. Such circuits are triggered when similar circumstances, real or imaginary, reappear. The recall of such circumstances automatically induces desires and cravings, on one side, or fears and rejections, on the other.
Depending upon the frequency or the intensity of the initial experiences, the normal inhibitory mechanisms reduce their strength and may fail to block the conditioned neuronal circuits that urgently demand repetition or avoidance. Compulsions and aversions arise then and, as things get worse, they get totally out of control.
During mindfulness meditation, a significant number of inhibitory neurons are turned on and off continuous and indiscriminately; they get “exercised” in the routine, so to speak, and eventually the lazy ones—those “guards” that had gone on strike—go back to work, which is to say, go back to their regular blocking duty. As either a drugless or a complementary therapy, mindfulness meditation is showing a very promising potential in the prevention and treatment of some mental disorders.
Mind exercisingDuring physical and mental exercising routines, such as dancing or ball juggling, the neuronal work in the brain is mostly excitatory—it triggers action on other neurons—while in the peripheral nervous system, in a symphonic coordination of muscular tensions and releases, it is both excitatory and inhibitory. In purely mental exercising such as chess or Sudoku, on the other hand, the neuronal activity, which is now centered in the brain, is mostly of an excitatory nature. How do we then exercise our brain inhibitory neurons, roughly one fifth of the one-hundred-billion (or 1011) total neurons? How do you train such important cells the work of which—stopping other neurons’ doings—goes very much unnoticed? The answer is through the practice of any form of meditation and, for increased effectiveness, through the practice of mindfulness meditation, a mental discipline which was developed by Siddhattha Gautama, the Buddha, twenty five centuries ago.
Mindfulness is the permanent awareness of life as it unfolds; mindfulness meditation—the quiet and still sitting while focusing attention on some object, means or mental device—is the practice of “directed” mindfulness to make it a permanent habit. Geographically and historically, breath observation is by far the most common meditation tool; as meditators gain experience, they progressively might focus attention on other objects or means such as their bodies, sensations or mind states, or the actual meditation experience.
Neurology Basics
Simply stated, excitatory neurons are nerve cells that send increasing activity signals to their neighbors; inhibitory neurons, reciprocally, are those which order their neighbors to reduce or stop activity. Nervous signals are carried by some chemicals, known as neurotransmitters, which travel through interneuronal junctions or synapses; each neuron is connected to its neighbors by an average of 7,000 synapses (so our brain contains some 7 x 1014 synapses).
Brain functions result from excitatory and inhibitory neurons being connected together in different ways to form neural circuits—ensembles of neurons that process specific kinds of information. When first acquired or experienced, every learned or developed functional task—a piece of knowledge, a skill, an image, a memory, an emotional state, a preference, a dislike—becomes a neural circuit.
Synapses within a neural circuit weaken (or strengthen) with the reduced (or increased) activity of the circuit’s function. Every time a task is repeated or re-experienced, the corresponding neural circuit is “re-run”, strengthening the associated connections in the repetition. Seldom used circuits weaken and the associated function is eventually forgotten. Medical science knows today that the underuse of the brain does decrease both length and quality of life.
Mindfulness meditation
The practice of mindfulness meditation is the “purposeful” stopping of as many common alert state functions as feasible. What happens to your neurons while you meditate? Though every meditator follows his or her personal routine, the steps below represent a typical sequence which, for the purpose of this note, contains enough information for the intended association between neuronal inhibition and mindfulness meditation. While beginners normally stay within the first four or five numerals of this progression, disciplined meditators regularly reach and experience the highest introspection levels. The sequence is as follows:
1. Just by sitting still, quiet, with eyes closed and in an isolated place, an important fraction of your excitatory neurons—the motors, the talkers, the observers, the listeners and, if you have not eaten anything during the previous hours, the digesters—go to rest. Thus far, except for the posture, meditating and sleeping are similar activities.
2. When you become aware of gross sensations—your clothes, the contact with your seat or the floor—the inhibitory neurons that ordinarily block such sensations are turned off (you perceive such sensations; sensations are on).
3. When you focus attention onto the flow of your breath, inhibitory neurons turn on to shut off distractions.
4. As distractions interfere, inhibitory neurons turn off to let distracting thoughts enter (involuntarily). When you notice you are distracted, you go back to Item 3 (inhibitory neurons on again.)
5. As, with practice and patience, you are able to maintain your awareness on your breath for longer and longer periods, subtle sensations appear in different parts of your body, which implies that inhibitory neurons, both at the central and peripheral systems, are turned off (sensations are “on”) wherever those sensations are perceived.
6. As you alternate attention between your breath and those subtle sensations throughout your body, you (a kind of) learn to turn off and on at will the inhibitory neurons that switch on and off these “subtle sensations.”
7. With continued and disciplined practice, you enter progressively deeper levels of joy, inner harmony, equanimity and pure consciousness (intense exaltation of mind and feelings.) At these stages, you always maintain awareness on your mind states and your actual meditation experience (going back to breath focusing whenever you get distracted).
What do you gain from the practice of mindfulness meditation? How do you benefit from the working out of inhibitory neurons, from continuously turning them on and off for a rather long period? The intuitive wisdom of the Buddha, who obviously knew nothing about neurons, answers these questions: With mindfulness meditation you develop the skill to be permanently mindful and reduce (and eventually eliminate) suffering (dukkha); the Buddha never spoke of mental disorders. How does this happen?
The role of inhibitory neurons is similar to that of building guards; when they are accurately and dutifully working (active, “on”), intruders do not cross the threshold (they are inactive, off), undesired people cannot enter and nothing seems to be happening. When guards do not show up to work, any person, intruders and disrupters included, can enter restricted premises. Similarly, when your inhibitory guards are off duty, intruding and disrupting thoughts—compulsive desires or intensive aversions—invade your mind.
Pleasure and pain
In our remote ancestors, pleasure and pain were survival mechanisms designed through natural selection. By generating the desiring emotions that call for the repetition of specific actions, the gratification of satisfying needs, both physiological and social, pleasure became a survival advantage for individuals and species. Similarly, the experience of pain led to the design of fear signals that set off automatic alarms when similar threatening dangers were encountered; the timely fight or flight conditioned response was instrumental for survival. Our desires and fears, therefore, are just simple natural reactions which our genetic code programs in our brain circuits; however, such responses are to be silenced by attentive inhibitory neuron once the demanding need or the threatening danger has been successfully managed.
Mental Disorders and Suffering
Unfortunately, reactions to demands and threats are sometimes mismanaged. If after the satisfaction of a particular need the neural patterns of desires are not shut off, the temporary wishes become permanent compulsions, addictions or obsessive demands. Similarly, if after the disappearance of a threat the neural patterns of fears are not shut off, the transitory worries become permanent aversions, panics or phobias. Minor cravings (the “controlled” daily drinking) and rejections (your “reasonable” hostility to someone “because you don’t have to like everybody”) are considered normal. The Buddha disagrees; according to him, the origin of suffering lies in these minor anomalies. It is only when the inhibitory mechanisms go wild and unruly that a variety of behavioral disorders arises and suffering becomes unbearable. Cognitive sciences are coming to the conclusion that many mental disorders, such as substance dependence, eating disorders, sexual addictions, obsessive compulsive disorders and post traumatic stress disorders, have roots in malfunctioning of inhibitory mechanisms.
Mindfulness meditation has already proven beneficial in dealing with such disarrays. As a therapy tool, it helps at both levels—the socially accepted and the psychologically unacceptable—but, as with any problem, prevention or early treatment is better than late correction. The Buddha properly addressed the elimination of the day-to-day suffering—the usual stress, the ordinary anxiety, the normal anguish of the common life—this is, the initial manifestation of the more complex problems. Mindfulness meditation, the exercise of large groups of inhibitory neurons which bring back inhibitory processes to order and harmony, was both the preventive and corrective prescription he recommended. What the Buddha knew intuitively since long time ago, cognitive sciences are learning the hard way today.
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