Michael teaches yoga and meditation, practises bodywork, and does philosophy relating to the mind, body, and yoga.

this is your brain on movement

Considering how common life is on this planet, it’s surprising that no one can come up with a single definition of what it is…One definition has to do with maintaining a non-equilibrium situation, and using that situation to build complex molecular factories that can reproduce themselves and evolve. Life is something that can control the speed at which energy flows through its system, manipulating the stream to maintain itself. Nothing that is in equilibrium can be alive.

Bubble physicist Helen Czerski is one of my science idols. This simple definition of life blew my mind when I read it a few months ago in her fantastic book Storm in a Teacup: The Physics of Everyday Life. But it also took me into a state of unexpected dismay. 

My fellow yogis and I immerse ourselves in, and work to disseminate, a culture in which one of the most vaunted values is the ability to find perfect balance in one’s self and in one’s life. But when I think about it, I have never met a yogi who has been able to achieve this simple-sounding yet surprisingly lofty goal. I am certainly no exception. Reading this passage, which Czerski places smack dab in the juicy centre of her book, caused me to doubt whether sattva guna (yogic homeostasis) was even a goal worth having if no human being—in fact, no living being whatsoever—will ever achieve this state. Perhaps, I told myself, I should just give up the vain struggle toward such a patently unachievable goal.

However, as I came to ponder over the course of the next few days, the fact remains that all of life is indeed a part of nature. Even human life exists not in spite of nature, but because of it. And according to Newton’s second law of thermodynamics, everything in nature desires equilibrium. For example, cooler air rushes in to fill the vacuum left by rising warmer air, thus creating the winds of the world. So, how does organic life fit in to this equation? Czerski in fact posits that life exists not necessarily in defiance of nature’s desired balance, but essentially as a temporary prolonging of the journey toward true homeostasis. 

We can see a microcosm of this model when we look at the life cycle of a fascinating (and adorably named) critter called the sea squirt.

Photo via  Stephen Goodheart

It is the kind of animal that your intuition might tell you shouldn’t even count as an animal. It lives most of its life stuck to a rock on the seabed, or a cliff, or occasionally on the hull of a ship. It receives its nutrition via a filtering process that brings in delicious microorganisms…and that sums up the extent of its activity. 

However, this describes only the adult phase of the creature’s life. The larva of the sea squirt, like the larva of a frog, is informally known as a tadpole. It looks, in fact, very much like an amphibian polliwog, and is a free-swimming individual with a tail outfitted with a rudimentary brain, spinal column, and muscular system in order to provide motility. The organism spends this (admittedly short-lived) first chapter of its life looking for a suitable spot to spend the rest of its days as a grown-up. The day that it closes the deal on its forever-home, the sea squirt’s DNA is preprogrammed to cannibalise its superfluous nervous and muscular systems for nourishment, which occurs at the same time as (and apparently as a prerequisite for) its metamorphosis into maturity. In other words, the little squirt settles down and eats its own brain

This TedTalk by Daniel Wolpert explains how the story of the sea squirt can teach us a lot about the purpose of brains in general. A self-proclaimed “movement chauvinist,” Wolpert theorises that brains exist solely in order to create movement. Even though many of us tend to view cognition as a means of creating and communicating in abstract, higher-level concepts, the video demonstrates the unfathomably impressive trigonometry that accompanies making even the simplest movements which we take for granted. In Wolpert’s model, all of the abstract concepts we have, such as beliefs and creative impulses, are there to serve muscular motility. He explains the cognitive processes which drive animal movement as a “Bayesian inference machine” which combines sensory input with both memories and beliefs about what might occur next—all in order to create appropriate muscular action. Neuroscientists find this process astonishingly complex, and as Wolpert points out, so do the engineers who attempt to build robots with movement capacities that can approach anything near the fluid accuracy that even human toddlers are capable of.

Philosopher Ellen Fridland takes things a step further. In this paper she argues that higher-level abstract mental concepts exist not just in support of physical movements, but that “the flexibility, creativity, agency, and deliberateness involved in [physical] skill refinement play key roles in the development of human-style intelligence.” In other words, fully abstract, conceptual, higher-level thought happens in part as a result of our learning how to acquire an adaptable and flexible mastery over our environment. She points out that what separates human beings from other animals is not only our higher-level cognitive functioning, but also the fact that we appear to be the only creatures who learn skills (such as playing the guitar, doing a handstand, or solving a Rubik's cube with feet) that have no obvious evolutionary advantage. In Fridland’s view, this odd human trait may very well may provide a clue as to how abstract thinking emerges.

Let's look at Fridland’s example of a child learning how to kick a ball successfully. The child may already know in general how to kick a ball, but in order to do it in a fashion that approximates the precision and intentionality with which her older sibling does it, she will have to break the action down into phases. She will experiment with the speed and number of steps she takes on the approach. She will test different levels of muscular engagement in order to see how far the ball flies when her foot makes contact. She will try kicking it with various parts of her foot to see which option sends the ball in the desired direction. She will make mistakes, and she will then break the steps down into even smaller steps in order to maximise the success rate of her movement. Eventually, all the broken-down steps approach a certain level of fluidity, and the various aspects of the sequence will no longer seem like separate pieces. But interestingly, in the act of deconstructing the movement, many of the refined procedural steps will have attained a certain degree of what we might call “transfer value.” So the run-up to kicking the ball can be generalised, essentially, in order to function in a similar fashion as the run-up to a cartwheel, or the run-up to a cannonball into the swimming pool. The child can also learn to recombine the pieces of the sequence, so that the order in which she performs them does not ultimately need to match the order in which she originally learned them.

As Fridland notes, this embodied experience of refinement and generality requires a certain degree of introspection. Both Wolpert’s team and that of neuroscientist Rick Grush have provided evidence that the brain creates a mental model—a “simulation,” or an “emulator”—of every movement the body engages in. Fractions of a second before you act, your brain mocks up the precise trajectory, effort, and timing you will apply in order to execute that action. Therefore, before we can affect the world around us, the entire system needs to look within. All of the basic maps required for manifestly survival-related movement appear to be pre-loaded software. This is why, for example, a task like walking from one side of the room to the other will look remarkably similar across a wide range of individuals. Even though the hips and the shoulders are both ball-and-socket joints with exceptional ranges of motion, it is unlikely that most individuals will randomly flail appendages out away from the midline as they go. Our mental maps are programed with efficiency of movement in mind.

But as humans appear to be the only animals who consistently engage in acquiring new skills just for the sake of it, I posit that we also stand unique in consciously creating brand-new mental maps as a result. In the process of skill learning and refinement, we constantly reinforce the necessary impulse to introspect both in the moment preceding the task and in assessing how we feel about our performance ex post facto. For Fridland, the coalescence of highly sensitive introspection and physical sequence recombination serves as a platform for learning how to recombine, generalise, and reflect upon our mental representations as well, at the next stage of development. 

On the other side of life’s journey, studies of the brain’s ageing process also support the supreme role that movement has in cognitive function. Among the most effective means to maintain your marbles is to dance frequently. This opportunity to engage the entire body in movements that are well beyond the quotidian serves also as a way in which to keep the internal movement emulator fit as it fires away to find the most energetically efficient path toward executing a brand new sequence of movements. (NB—I have not found significant longitudinal studies of the effects of yoga āsana on cognitive function in later life, but I would imagine that the practice might have similar effects—provided that there is some degree of variation in sequencing.)

I suggest that the same mechanism is at work when an individual speaks a second language—another activity which research demonstrates can delay the onset of dementia by an average of nearly five years. Speaking may not involve the kinds of full-body versatility that learning new dance moves does; however, the movements of the vocal apparatus require a stupendous degree of specialisation and refinement. All in all, the languages of the world have around 800 phonemes—the specific combinations of tongue, lip, and vocal chord movement needed in order to produce distinct consonants and vowels. The average language has about 40 phonemes, so even with overlapping sounds, any given bilingual person will make use of a significantly larger number of overall phonemes than any given monoglot. This means that he will train his vocal apparatus, along with the necessary mental maps to produce the required movements, to a more refined degree. This process will necessarily recruit a greater number of active neurons, which may serve as an effective bulwark against cognitive decline. 

And now I must address the 800-pound gorilla in the room. If the brain is for movement, and if movement keeps the brain healthy, why am I such a massive advocate for seated meditation? Well, I’m glad you asked. 

If you watch the Wolpert TedTalk, which I really do encourage you to check out, he shares at one point a video of a young American lady setting a world record in a sport called cup-stacking. In this event, the object is to stack and unstack a group of plastic cups a number of times, in a particular order, in the shortest time possible. Since Wolpert’s talk, a young man named Austin Naber became the new world record holder. He also became the subject of a study for neuroscientist David Eagleman. In his book The Brain: The Story of You, Eagleman challenges himself to learn the cup-stacking sequence in order to have an in-depth analysis of the functioning of his own brain as compared to Naber’s during the process. Please watch at least the first :35 of this video if you don’t have time to watch the whole thing right away:

In the book, we learn that in an EEG comparison, Eagleman’s brain was exhibiting high levels of fast-moving beta waves. These are, understandably, the same kinds of waves the brain produces when faced with a stressful task. Naber’s brain, on the other hand, entered an alpha-wave rhythm state during the cup-stacking. We usually associate this type of brain rhythm with a state of deep rest, such as the mentally quiet moments one experiences on the brink of sleep and, incidentally, during many forms of meditation

According to Wolpert, a successful internal simulator can significantly reduce the amount of sensory “noise” when the body is performing any given task. The mental emulator serves, for example, as a means of cancelling out sensory input from the body’s own movements when it is attempting to act on an object in the world. (This is the very reason it is nearly impossible to tickle yourself, by the way.) In employing the effective simulator, Wolpert says, the brain engages “dedicated neural circuitry” in order to subtract as much noise as possible from the equation by reducing variability of movement. In contrast, the “noise” of variability increases as the force gets bigger, so the key is—as Wolpert emphasises—to “avoid big forces.” I take this as neuroscientific evidence for the ubiquitous advice of “not getting in your own way” and of “not trying too hard.”

As the Naber video demonstrates, executing a task with such a supreme degree of efficiency and minimal "noise" requires new neural pathways which change the physical structure of the brain. Many meditation practices are also associated with structural differences in the brain, and perhaps with a greater degree of transfer value. I believe that more evidence may eventually show a strong measure of correlation between the restful, alpha brain waves that meditators cultivate and the efficiency of specific movements, the streamlining of skill acquisition, or even higher levels of cognitive functioning. This seems to be the very thing that yoga gurus, Zen masters, and martial arts sages point to when they speak of executing any given action in a state of “no-mind” in order to achieve the highest standard of effectiveness.

So in the end, perhaps we can cultivate even stillness primarily in order to support our movements. Seen as a tool with which we can more effectively "control the speed at which energy flows through" us, it seems rather fitting that, in spite of what Yoga Journal always advertisesyoga actually appears to slow down metabolism. And slower metabolism is linked to greater longevity. So if Czerski is right in her definition of life as that which temporarily refuses to submit to equilibrium, perhaps the equilibrium we yogis strive for is ultimately a temporary means to support of our own elegant, dynamic, organic effervescence. And while we may never find a state of permanent balance in this lifetime, the process of refining ourselves may at least lead to an ability to live in a greater degree of harmony with the natural world of which our lives are just a small part, for a time that is only as brief as a bubble.

Further Reading: For a wonderfully elegant overview of the brain's body maps, check out The Body Has a Mind of its Own: How Body Maps in the Brain Help You Do (Almost) Everything Better, by Sandra Blakeslee and Matthew Blakeslee

ex libris...

yoga and epigenetics: muting the buzz