In order to assess the potential benefits of any meditation technique, we must consider in detail what happens in the body, especially in the brain but also overall in the central nervous system. This is the case with Mindfulness meditation, a technique derived from Vipassana meditation, a practice which medical professor Jon Kabat-Zinn has « secularized » so that it would be readily accepted in all strata of American society. This apparent « secularism » has allowed Mindfulness to spread easily, especially in the medical community. The practice can be learned by simply reading a book on the subject as these usually have an accompanying CD, by informing oneself over the Internet or by participating in a paid, eight-week structured course. This meditation technique consists of training the mind to focus on the present moment by putting one’s attention on the breath or on any other bodily processes, without making a value judgment. This attention can be maintained outside the strict framework of “eyes-closed” meditations, and can be practiced while eating, walking, working, etc. Several studies show that Mindfulness is quite effective in reducing stress, anxiety, pain or fighting against the recurrence of depression. How does Mindfulness meditation, Mindfulness in short, affect brain functions? Before answering this question, a side step is necessary to review how our brain works.
This organ weighing one and a half kilo (three and a half pounds) consists of about 200 billion cells, 10% of which are neurons, 4 million kilometers of axons, and billions upon billions of synapses. Its role is to unify the diversity of the outside world manifested as billions of bits of information with which it is constantly bombarded through the five senses. More and more experts in neuroscience admit that the seat of consciousness lies in the non-material activities of the brain, much like a radio station receiving its programs through electromagnetic waves. One fundamental aspect of brain functions are the several ranges of electric waves that have been identified through the use of electroencephalography (EEG) technology: delta waves below 3.5 Hz, theta waves between 4 and 8 Hz, alpha waves between 8 and 12 Hz, beta waves between 12 and 25 Hz and finally gamma waves above 25 Hz. These waves testify to specific activities in the rest of the physiology: delta waves are usually associated with deep, dreamless sleep, theta waves correspond to a state of deep relaxation while awake, alpha waves characterize a state of relaxation, beta waves are those of normal activity and finally gamma waves reflect intense activity, often associated with creativity.
Despite its visible complexity, the brain can be divided into four main anatomical parts: the front area of the prefrontal cortex, the rear areas of the parietal and occipital cortices as well as a temporal lobe on each side of the two hemispheres. The occipital area governs vision, the parietal area relates to space and time, the left temporal area governs memory and the language, the right temporal area relates to sensory functions such as hearing and tasting while the prefrontal cortex is linked to all the advanced functions pertaining to the identity and personality of the subject. In a broad outline, the front of the brain deals with the inner world of the subject, whereas the rear of the brain deals with our representation of the external world (vision, hearing, touch, etc.), the observed object. The prefrontal cortex of the human brain is located just behind the forehead. It governs essential cognitive functions such as intelligence, moral reasoning, beliefs, emotional stability, personality development, self-confidence, creativity, leadership, academic performance, the ability to make decisions, etc. Alpha waves define the subject and therefore the observer, beta waves define the observation process and gamma waves define the observed object.
Let us now examine in detail the phenomenon of stress, a term so overused that its exact characteristics are largely unrecognized by the public. Discovered by Hans Selye in the 1930s, stress is the organism’s response to a situation that an individual is afraid of not being able to manage because his prefrontal cortex judges it to be difficult. Conflict, examinations, medical surgery, work overload … the causes of stress are infinite. As a response, the organism changes its chemistry in order to react. It is important to note that the same situation that may stress you may energize your neighbor. Stress is always a personal response resulting from an interpretation of the prefrontal cortex. The latter – whose role is often compared to that of a CEO (Chief Executive Officer,) – manages the functioning of the brain. Under stress, regardless of its origin, it activates the amygdala, which in turn activates a level of vigilance in the body via the limbic brain, triggering a whole series of chain reactions in order to facilitate action and ensuring survival in case of danger. On the level of the physiology, there is an increase in heart rate, constriction of blood vessels or muscle bandage. In addition to a rise in cortisol levels in the blood, the brain secretes epinephrine, a hormone that slows the digestive system and increases respiratory rate, blood pressure and blood sugar; all factors that prepare the body for action. This hormone momentarily disconnects the prefrontal cortex from the brain to allow the amygdala and the limbic areas which house the survival mechanisms to take over. Once the stressful event is passed, rest restores the normal functioning of the body, including that of the amygdala.
Extensive literature on the subject pretends that a certain amount of stress would be necessary to be productive, when it is really challenges or deadlines that stimulate us to act or take risks. In case of mild stress, the chemical changes in the body fade quickly and the parameters return to normal levels after the rest of one or two nights’ good sleep. If stress becomes chronic, the amygdala is activated permanently, creating a state of hypervigilance that a few nights of restful sleep are not enough to reverse. Such a state for example, would be justified by the fear felt when crossing a jungle surrounded by enemies. From then on, the amygdala takes control of the prefrontal cortex, which is what happens in case of ‘burn out’ and post traumatic stress. Only deep rest brought by meditation techniques ease these extreme cases, whether they involve stress linked to the violence of war or the intense stress of work.
As another result of stress, neural interconnections, whose richness ensures the proper functioning of the brain, are gradually destroyed, and attention becomes fragmented. The individual loses the ability to concentrate. He is able to only place part of his attention on his actions. Consequently, a large amount of thoughts escape his attention. His perception of time is also fragmented; he is simultaneously in the present, past and future. A study conducted at Harvard University by psychologist Matthew Killingworth shows that when under stress, we spend 46.9% of our waking hours thinking about something other than what we are doing. Thirty percent of our time is spent daydreaming during all our activities. Mental life is therefore marked with a certain « non-presence ».
The beneficial effects of most meditation techniques on stress rest on the plasticity of the brain; that is to say the ability of the brain to change its structures based on the stimuli it receives. So, frequently used neural circuits, those with rich neural interconnections, consolidate and develop. Those that are used infrequently or are victims of stress eventually wither. Research shows that different meditation techniques increase the connections between different parts of the brain.[]The white matter [] of the brain of people practicing a meditation technique shows more nerve fiber bundles connecting the different parts of the brain, including the corpus callosum, which connects the right and left hemispheres, the pyramidal tract which connects the brain to the spinal cord and finally the uniform beam linking the frontal lobe to the limbic system, the seat of emotions . Among other findings, research shows a high level of activity in the parts of the brain that help form positive emotions such as enthusiasm, self-control and joy, accompanied by a lessening of activity in parts connected with negative emotions, in particular the area related to fear and anger.
The many researchers who have worked on the various meditation techniques and their effects on stress met in 2013 in New York to bring some order and consistency to their work, particularly in terms of assessment criteria. Failing to define common criteria, they classified meditation techniques into three families that are differentiated not only by their procedures but also by how they impact the workings of the brain. These are « meditations with focused attention”, « meditations with unfocused attention » and « meditations with automatic transcendence. » Each type of meditation takes a different angle of exploring consciousness, each inducing different experiences and effects. Compassion Meditation, which belongs to the category of « meditations with focused attention, » develops the « emotional system » of the brain. The emotional life of the individual becomes richer and fuller. Mindfulness and Vipassana meditations, which are « meditations with open and unfocused attention, » develop mindfulness of situations and increase mental and physical well-being. Transcendental Meditation, which is a « meditation with automatic transcendence, » goes beyond the development of any particular competence. It develops overall coherence in the brain, especially visible by means of an electroencephalography (EEG) in the alpha waves in all parts of the brain, starting with the prefrontal cortex.
During the practice of Mindfulness meditation, the focus of this article, attention is brought to the breath or any other bodily process. This mechanism is accompanied by an acceptance of the present moment without judgement of anything that happens. It decreases the flow of thoughts issued by the wandering mind. A review of EEG activity reveals activation of the left prefrontal cortex, a slight increase in alpha and theta waves in the brain, but most notably a sharp increase in the gamma wave range, a phenomenon that some call the « signature of Mindfulness”. During periods of intense stress, a wandering mind forces the person to make an effort to concentrate in order to keep the attention on the breath. This effort of concentration creates mental fatigue. At this stage of the practice, some give up, convinced that the technique does not work, that it is difficult or that they are going in circles. Sometimes it also happens that the person lets go, in which case attention goes naturally and effortlessly to a state of deep rest and inner silence. Those who practice Mindfulness – or Vipassana, the Buddhist meditation which served as its origin, certainly have had accidental experiences of that state. During practice, it can also happen that the person navigates difficult moments, similar to psychotic episodes. In an academic article on the subject , British psychologist Tim Lomas, lecturer at the School of Psychology of the University of East London, said that although most people benefit from Mindfulness, a quarter of them encounter « considerable difficulties » in terms of identity. A possible explanation: according to Mr. Lomas, Mindfulness makes people aware of their distress without offering them a solution. Nevertheless, these difficulties put in question the analogy that the brain operates like a muscle that needs exercise.
Concerning the general effects of this technique, the work of Dr. Richard Davidson (University of Wisconsin) shows that mindfulness develops clarity of intent, altruism, kindness, empathy and compassion. On her part, Dr. Sara Lazar (Harvard) showed a thickening of the cerebral cortex in certain specific areas of the brain. This result was very clear in brain areas relating to vision, the insula cortex in the right hemisphere and the upper and middle sulcus (grooves) of the prefrontal cortex. The insula in the right hemisphere, which allows one to become aware of sensations in the moment, is developed, which is not surprising since the practice of mindfulness precisely focuses attention on the breath or any other biological processes. The activation of the sulcus of the prefrontal cortex testifies to better emotional stability. Mindfulness develops more presence by taking the attention away from mind-wandering. The part of the brain connected with the outside world is strongly activated during practice. Among meditators who have practiced for a long time, the work of Judson Brewer and his team showed on a small scale the activation of the left prefrontal lobe associated with decreased activation of the default mode network , indicating a state of activity of the brain.
A study published in “Biological Psychiatry” at the beginning of 2016 attempted to assess the impact of Mindfulness on a group of 35 unemployed people with high levels of stress. Two groups were formed: the first group practiced Mindfulness meditation for 3 days, while the second group practiced a classic relaxation technique. For 3 days, the 35 participants while in a state of rest went through the scanner 5 minutes before starting their programs and again after practicing. In addition, blood samples were taken before the start of the session and again four months later to measure interleukin 6, a biomarker of inflammation. The results: the scans showed that the practice of Mindfulness increased connectivity in the dorsolateral prefrontal cortex (left prefrontal), which was not the case with the group who practiced relaxation. Furthermore, participants who meditated saw their interleukin-6 levels drop. According to David Creswell, lead author of the study , the brain’s neural reorganization favored better stress management and one of its notable results, inflammation.
Another study conducted last year at the University of San Diego  also showed that Mindfulness deconstructs and transforms the relationship with time, which could promote the creation of false memories and have a negative effect on memory tests. In this study, three hundred participants were divided into two groups. The first was invited to practice a fifteen minute guided meditation where attention was focused on the breath. The second group only needed to stay calm, keep their eyes closed and think of what came to their minds. Both groups were subjected to a standard test of memorizing a list of fifteen words linked semantically to the term « garbage ». They were asked to remember as many words as possible. Result: both groups remembered the same number of words. In contrast, 39% of participants in the group who practiced Mindfulness remembered reading the term « garbage » in the list versus only 20% of the other group! The actual term of course was not included. The authors of the study conclude: « With Mindfulness meditation, memories become less reliable”. A psychiatrist and specialist of therapies based on Mindfulness meditation, Dr. Yasmine Lienard tried to explain this surprising result in a column of the French magazine Sciences et Avenir: « When meditating, something like a dissociative fugue occurs. One learns to forget who one is, and where one is according to one’s habitual concepts and this can create a secondary cognitive disorganization. Meditation deconstructs the usual landmarks and transforms the relationship with time. People feel better, but the relationship with the world is transformed. They should be supported and so there is no impact on daily life, it is necessary to provide them with resources so they remain stable”. It should be noted that no other meditation technique shows a similar result in memory tests.
Systematically reported by the mainstream media, numerous studies have been conducted in recent years on the technique of Mindfulness. What lessons can be learned from them? A meta-analysis published early in 2014 in the Journal of American Medical Association, Internal Medicine  concluded that the results of this practice in terms of health are « low to moderate » on levels of anxiety, depression and pain. Professor of internal medicine at Johns Hopkins School of Medicine, Madhav Goyal, the principal author of the meta-analysis estimated that more research with more significant samples is needed. His meta-analysis was conducted on a sample of 3,500 participants over 47 studies. After a watchful evaluation of the placebo effect of his studies, Madhav Goyal believes that the effects of Mindfulness on health, mood, eating habits, sleep or weight regulations are not significant. This finding confirms the one from the American Heart Association in 2013 that ranked Mindfulness meditation among the meditation techniques where studies did not provide enough scientific evidence about its positive effect on hypertension.
Unaware of the research, the public has adopted this technique that can be learned from a book or downloaded to a mobile device. If it gains popularity, its success is in large measure due to the « secularism » of the practice. Although inspired by Vipassana meditation, this technique has willingly sacrificed all ritual, finding itself somehow cut off from its roots: it no longer has access to the thousand-year old experience of Vipassana meditation, knowledge which is nonetheless necessary to move forward on a path of evolution that is much more subtle than what the marketing discourse allows us to see. Other meditation techniques have not cut their ties to the tradition from which they originate, which does not prevent them from being practiced by people of all religious beliefs and social backgrounds. Note also that U.S. companies that have introduced Mindfulness to their staff still rely on teachers from the Buddhist tradition. At Google, Chade-Meng Tan, a man of Buddhist tradition, organizes the teaching and practices of the staff, which is paradoxical for a technique that affirms its « secularism », but quite justified when it comes to answering the many questions that can arise from any meditation practice. Another factor contributing to the success of Mindfulness: a well-crafted marketing approach centered on stress reduction through presence, a notion presented as the alpha and omega of the practice, an access point to happiness. This association is partially based on the fact that a wandering mind is indicative of a state of unhappiness. However, we know that the present itself can also be a source of unhappiness!
As a result of the secularization of the approach, the spiritual dimension of this meditation technique has completely disappeared, while the practice inevitably awakens that dimension in the person, sometimes leading to difficult experiences. How to explain such difficulties? The American doctor Daniel Ingram , a specialist in Theravada Buddhism, leader of a meditation forum attended by over 5,000 people, believes that according to Theravada Buddhism, these experiences are part of the evolutionary path to spiritual awakening. In this tradition, there is a phase in the practice which induces experiences related to the identity that can lead to depression and even suicide. That’s where the connection with a tradition, even the presence of a spiritual master become indispensable in navigating unharmed through such experiences and attain spiritual awakening.
To return to Mindfulness, presence is introduced as the only short and long term aim of this meditation technique, while the Buddhist traditions will seek nothing less than spiritual awakening. Recall that it was while meditating under a tree that the Buddha attained cosmic consciousness, a key step in enlightenment. We note that the state of presence glorified by Mindfulness has no specific biological characteristics. It is an ordinary waking state without mental wandering. Through various paths, all meditation techniques bring attention to this same present moment, away from mental wandering. From this point of view, Mindfulness therefore contributes nothing special. How long does the attention remain focused on the present moment? Everything of course depends on the person and his level of stress. Among veterans of war or victims of attack with post-traumatic stress, their attention is continuously captured by traumatic memories, the amygdala having stolen control of the brain from the prefrontal cortex. This is why these people struggle to live a « normal life » in their professional environment and struggle to form meaningful relationships
Conclusion: Studies show that Mindfulness obviously develops qualities of altruism. It leads the brain of the meditator to remain focused on the present moment, which allows for a certain reduction in anxiety, depression and pain. Its effects on health are yet to be validated by further studies.
Jo Cohen, Human Resources Consultant
(*) Cet article est une traduction de l’article français intitulé « Comprendre les effets de la pratique de la méditation de la pleine conscience ». Il s’adresse à un public anglo-saxon.
 ‘Long-Term Meditators Self-Induce High-Amplitude Gamma Synchrony During Mental Practice’, Antoine Lutz, Lawrence L. Greischar, Nancy B. Rawlings, Matthieu Ricard and Richard J. Davidson, Proceedings of the National Academy of Sciences of the United States of America.
 The white matter is a material class of central nervous system, mainly composed of axons associated with myelin sheaths or not of neurons. It connects different areas of gray matter where the cell bodies of neurons are located.
 « Enhanced brain connectivity in long-term meditation Practitioners ». Luders E, K Clark et al. Neuroimage 2011 June 6
 « A Qualitative Analysis of Experiential Challenges Associated with Meditation Practice » Tim Lomas, Tina Cartwright, Trudi Edginton, Damien Ridge. Mindfulness
August 2015 Volume 6, Issue 4, pp 848-860 First online: 10 August 2014
 Radio BBC reported a few cases you can listen in English. http://www.bbc.co.uk/programmes/articles/2nB1psRz3JFQpzDh6J2Z6xl/is-mindfulness-meditation-dangerous
 « Meditation experience is associated with differences in default network activity and fashion connectivity », Judson Brewer et al. Proceedings of the National Academy of Science of the USA, dec.2013.
 It is a network of brain regions that are active when a person is more focused on the external world, his brain being then considered in a state of rest.
 The study was conducted at the Department of Humanities and Social Sciences at Carnegie Mellon American University.
 The results of this study were published in the journal Psychological Science.
 « Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis, » Dr. Madhav Goyal, Sonal Singh, Anastasia Rowland-Seymour, Zackary Berger, Padmini Ranasinghe and Eric Bass. JAMA IM January 2014.
 ‘Long-Term Meditators Self-Induce High-Amplitude Gamma Synchrony During Mental Practice’, Antoine Lutz, Lawrence L. Greischar , Nancy B. Rawlings , Mathieu Ricard and Richard J. Davidson, Proceedings of the National Academy of Sciences of the United States of America.
 Luders E, Clark K et al. Enhanced brain connectivity in long-term meditation practitioners. Neuroimaging. 2011 June 6Google+
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