The Yoga Sutras of Patanjali, are a collection of 196 Indian sutras on the theory and practice of yoga, compiling organized knowledge of Yoga from older traditions. Written prior to 400 CE, Sage Patanjali says, ‘yogaś-citta-vr̥tti-nirodhaḥ,’ which literally translates as, ‘yoga is the cessation (nirodhah) of fluctuations (vrtti) of the mind (citta).’ For thousands of years, Yoga has been taught in many forms and fashions, with the aim and claim of helping the student achieve peace of both mind and body. Each of which greatly impact one another.
In recent studies, science has finally been able to prove that Yoga helps to facilitate beneficial function changes of the body on a cellular as well as a molecular level. As biomedical research has evolved, we now have the tools to evaluate how Yoga is affecting people physiologically. Magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT) have all shown changes most commonly in the prefrontal cortex, hippocampus, tempro-parietal cortex, and insular cortex of long term practitioners of yoga and meditation. [1]
Neuroimaging has also been a powerful tool. It allows us to view the structural changes to the brain’s plasticity. Our brains and nervous systems have the ability to rewire themselves according to what we focus on, this is called neuroplasticity. Through the practice of Yoga, we begin to create more neural connections. Along with neural connections come increased nerve fibers, through the nervous system, to either the part of the body associated with the posture we are practicing, or the body as a whole. This is not only achieved through physical practice but also via the practice of meditation. These added neural connections and neural fibers are what compile to create our bodymaps.
Bodymaps are the parts of the brain that light up when we feel something physically, or even think of, or visualize, something. In turn, if a scientist was to stimulate a specific area of the brain with electricity, you would feel it in the associated body part, without that physical area ever being touched.
As we practice something, our ability to receive more information about the subtlety of what we are doing increases. The implications of the newfound knowledge of our bodymaps are broad but let’s keep it simple. For instance, when you are first learning to drive a car, you might have to run down a long list of things to check prior to starting the engine, as well as a continual list of things to check while the car is in motion. Being a new driver, the body may be under an immense amount of stress as it responds to the anxiety of the mind. As you get more and more comfortable, your body decreases its stress response and eventually you are figuratively driving on autopilot. Before you know it you’re hoping in the car, starting the engine and on the road without a second thought. All because you have practiced so much, your brain has made that once daunting checklist, second nature. Your bodymaps, in regard to this task, are clear and detailed. You no longer have to focus so intently on what you are doing, in order to accomplish the task. Through practice, you have created a map so clear, it’s easy for both the mind and body to follow, helping the body to decrease it’s stress response, the objective of Yoga.
In short, whatever path we take most frequently, will be the path easiest to follow. Anything we focus on, in any given moment, we are training ourselves to more easily shift our attention in that direction. Whatever we are doing or thinking, we are becoming better at it, our bodymaps become greater in number and more detailed. This has been proven, using the tool of neuroimaging, among others.
Having better awareness of ourselves helps us to begin managing our stress responses, which is largely the aim of the physical and meditative techniques to Yoga practice. Scientifically speaking, as we practice Yoga and meditation, we increase the neurological detail of our nervous system and bodymaps, making us better in tune with ourselves. But Yoga doesn’t only help us become more in tune with ourselves. As we develop our own bodymaps we are becoming more in tune with the our surroundings.
Through the observance of others we design a more detailed bodymap. Each of us possess what are called mirror neurons. Accurately named, mirror neurons are referred to as the science of human empathy, reflecting what we see around us. They give us the ability to feel what it would be like to do something, by simply observing someone doing it or even imagining it. When you find yourself responding equally to the facial expressions of the characters in a movie you are watching, or as your emotions change as you read a story, your mirror neurons are being triggered [2]. As we perceive not only the actions of others but also their emotions and facial gestures, we are unconsciously activating our own mirror neurons.
Neuro imaging has played an integral role in helping us to find the scientific backing for the benefits of regular yoga and meditation practice. Molecular biology has also given us the ability to see the action of the transmitters and molecules as we practice mindfulness and movement. Essentially, science is discovering that through our increased ability to feel our own bodies through the development of our bodymap, we increase our ability to feel the world around us. We literally begin to feel more information.
Now that we have covered the effects of meditation on brain activity during a specific task, let’s discuss the results of investigations on the resting state of the brain, due to the effects of ongoing, regular Yoga and meditation practice.
Situated near the thalamus, deep in the midbrain, each hemisphere contains a caudate nucleus. The caudate nucleus' of both hemispheres are centrally located near the basal ganglia. A Harvard study by Doctor Sara Lazar found that there was a greater widespread functional connectivity of the caudate in experienced Yoga practitioners and experienced meditators than in controls [3]. Through this study, increased activation in the caudate was reported during sustained meditation.
Because the greater connectivity occurred via widespread connections through the frontal, temporal, and parietal region, versus being driven by a single, strong connection, we can assume that yoga practitioners and meditators have more efficient basal ganglia cortico-thalamic feedback loops than controls. Traditionally the basal gangli have been thought to primarily involve the control of motor function, but these structures are now considered to be critical for learning new complex behaviors. They are also involved in the expression of goal-directed behavior, and the processes that lead to movement, such as emotions, motivation, and cognition. The thalamus is a critical piece of the circuitry in this loop, as it is also involved in a variety of aspects of motivation, cognition and motor control [4].
The models of Travis and Wallace (1999), Newberg and Iversen (2003), Sperduti et al. (2012), Vago and Silbersweig (2012), and Gard et al. (2014a) explains that the repeated involvement of these loops during a state meditation, could be what strengthens this basal ganglia cortico-thalamic feedback loop functioning. This could be of great relevance as disturbances in these loops have been associated with mental health disorders, e.g., autism (Turner et al., 2006), obsessive compulsive disorder (Harrison et al., 2009), schizophrenia (Salvador et al., 2010; Simpson et al., 2010), and depression (Bluhm et al., 2009). Through consistent practice, old harmful patterns of thoughts and emotions can be unlearned and new positive behavior can be learned.
Based on the findings of Dr. Sara Lazar, there is proposed a three component model for the state of meditation. First being the, “interference control system,” which would support the switching to, and maintenance of, the meditative state through the involvement of the putamen and the caudate as part of a basal ganglia cortico-thalamic feedback system. Second component being a “thoughts monitoring system,” and third, a “self monitoring system.”
This three component model is very much similar to the way we self regulate [5].
Let’s connect each of the three components of the model for meditation, to it’s associated area of the brain.
The Central Executive Network rules our, “interference control system,”. This network is where our strength of attention resides. It helps us to behave in a way that is goal directed and encourages us to self correct when we make mistakes.
Our, “thoughts monitoring system,” is dominated by our Moral Cognition Network which supports motivation and intention setting and encourages us to do good things for others and ourselves.
Our sense of self-awareness is created by the frontoparietal control network (FPCN). This network helps us to figure out what’s going on and then inhibits inappropriate responses. This is the dominant system of our self regulation or “self monitoring system.”
Combining this finding of increased connectivity between caudate and several brain regions, and the fact that mindfulness based interventions have been shown to improve mental health (Grossman et al., 2004), leads to the fact that Yoga and meditation increase connectivity in caudate, improving mental health.
“Yogaś-citta-vr̥tti-nirodhaḥ”, Yoga is the secession of the fluctuations of the mind, said Patanjali, and we now know this is not opinion, speculation, or belief. It is purely a fact, a truth. The interpretation of truth differs according to time, culture and perspective, so it must constantly be reinterpreted. In this day and age, science is the leading edge in defining truth. Through the most recent decades, science has been the truth that we fall back on and science has confirmed that through yoga practice and meditation, the brain's structure and physiology can be, and is, altered, leading to the experience of peace, positive emotions and compassion. Science has proven the truth in The Yoga Sutras of Patanjali.
Resources
[1] ww.liebertpub.co; alternative and complementary therapies, Vol.20, No. 1
[2] ttp://www.yogachicago.com/jan10/neuroscience.shtml
[3] ttps://dash.harvard.edu/bitstream/handle/1/15034918/4360708.pdf?sequence=1
[4] ww.ncbi.nlm.nih.gov/pmc/articles/PMC4459637/
[5] ttps://www.yogauonline.com/contributor-posts/neuroscience-how-yoga-helps-your-mental-health-part-1-2