The summer of 2011 portrays weeks on end of agonizing urban heat. I can vividly remember it. Most afternoons, you would find me on the track, jogging for 40 minutes to an hour. I was enjoying it, even though it was like walking into an oven.
I seldom knew how time flew by. With my earplugs on, Brian Tracy was whispering motivational stories from his program The Power of Self-Confidence. His voice was pleasant, his language simple, his advice practical – a delight!
People inherently know the concepts and ideas pushed in such books and programs. Many folks read motivational books on an ongoing basis, yet never achieve anything in their lives. They barely move a finger. It took me some time to learn that achievement is about acting in a persistent, feedback-driven, and constantly-optimizing fashion.
Ever since my earlier exposure to self-development, I knew that there is something more to personal success than mere positive self-talk.
My curiosity got me to more solid grounds when I stumbled upon Joe Dispenza book, which presented a somewhat neuroscientific approach to human achievement. It got me hooked when I read how people can, in a systematic fashion, become better versions of themselves. I became more convinced that in self-growth there’s no magic, no overnight success, and no follow your passion bland advice. It’s more about pure, deep and systematic practice.
What about Skill?!
One great quote from Dispenza’s book will carry with me indefinitely:
Nerve cells that fire together wire together.
This is derived from the Hebbian theory to learning and it describes a basic mechanism to brain plasticity. I wrote about this here.
Until recently, the scientific community held that the brain cannot physically change itself, that it cannot rewire – growing new connections between neurons, solidifying existing connections, and even trimming weaker connections. Dispenza’s book provided the trigger for further investigation and, of course, for personal experimentation.
With a systematic approach, I managed to overcome my complex of driving (details here). It is how I became better in my English, both written and spoken. It is how I became better in all my sports practices It is how I learned that practice trumps passion and why follow your passion fails miserably for many folks. It is how I turned into a voracious reader. Ironically, I was that person who would laugh at those claiming to read books.
More importantly, from Dispenza’s book I learned how myelin plays a crucial role in skill acquisition and learning. This is where the unfeasible positive-self-talk meets neuroscience. When you can see some science behind personal success, you may be more empowered to do something about your life. Reading motivation is good for a start, but it will do you nothing in the long-run.
In Daniel Coyle’s The Talent Code:
Skill is a cellular insulation that wraps neural circuits and that grows in response to certain signals. The more time and energy you put into the right kind of practice—the longer you stay in the zone, firing the right signals through your circuits—the more skill you get, or, to put it a slightly different way, the more myelin you earn. 
The insulation Coyle talks about is myelin. To put in simple language:
Myelin wraps nerve fibers to increase the strength of the signal that passes through :
When we fire our circuits in the right way—when we practice swinging that bat or playing that note—our myelin responds by wrapping layers of insulation around that neural circuit, each new layer adding a bit more skill and speed. The thicker the myelin gets, the better it insulates, and the faster and more accurate our movements and thoughts become. 
From a structural point of view:
Myelin in situ has a water content of about 40%. The dry mass of both CNS and PNS myelin is characterized by a high proportion of lipid (70 to 85%) and, consequently, a low proportion of protein (15 to 30%).  
Cholesterol is an essential constituent of myelin :
Douglas Fields of NIH  thinks that you get more myelination as you become better at a certain skill:
For more than a century scientists looked at neurons through their microscopes and saw long fibers, the axons, extending from a neuronal cell body to a neighboring one, like an outstretched, elongated finger. Each axon was found to be coated with a thick crystalline gel. Anatomists surmised that the fatty covering must insulate axons like rubber sheathing along a copper wire. 
Later research showed that many axons are not coated at all. More over, some of the coated axons present gaps in insulation (every 1 mm). This gap is known as the node of Ranvier and its purpose may be to regenerate action potential and allow for saltatory conduction to occur. 
Modern investigation has revealed that nerve impulses race down axons on the order of 100 times faster when they are coated with myelin. Without myelin, the signal leaks and dissipates. For maximum conduction velocity, the insulation thickness must be strictly proportional to the diameter of the fiber inside. 
The process of myelination (wrapping nerve fibers with myelin) is known to occur at different ages. When you are born, there are only a few regions in your brain where myelin is prevalent. As you progress through life and reach your late 20s, researchers think that most myelin has been laid out.
Anecdotally, researchers have speculated that skimpy forebrain myelin is one reason that teenagers do not have adult decision-making abilities. 
Modern technology allows for non-intrusive deep brain investigation. With diffusion tensor imaging (DTI), we are now able to observe white matter dynamics in the cortex.
In 2005, Professor Fredrik Ullen from the Stockholm Brain Institute found that the more hours a day a musician had practiced over time, the stronger the DTI signals were in these white matter tracts; the axons were more heavily myelinated or tightly packed. [1,11]
In another study, neuroscientist Vincent Schmithorst of Cincinnati Children’s Hospital used DTI to compare whiter matter in children 5 to 18 years old. 
A higher development of white matter structure, Schmithorst found, correlates directly with higher IQ. Other reports reveal that children who suffer severe neglect have up to 17 percent less white matter in the corpus callosum. 
As proposed by Fields  experience (and practice, I would add) has an impact on myelin formation. Unsurprisingly, the resulting myelin would further support the learning process. So, the more you practice, the easier it becomes and the faster it is to keep improving.
Far from the bland positive self-talk of personal development books, skill acquisition and mastery may now be observed through the lens of epigenetics (the impact of environmental stimuli on physiology). When more signals pass through certain neurons, this is a call for myelination:
A type of glial cell called an astrocyte releases a chemical factor when it senses increased impulse traffic. This chemical code stimulates oligodendrocytes to form more myelin. 
There you have it: epigenetics in action.
On the other side of the spectrum, a mutation in an astrocyte gene leads to abnormal myelination and mental retardation . Other pathologic conditions with genetic roots have been attributed to myelin dysfunction:
Polymorphisms for several myelin genes have emerged as unexpected risk factors for:
schizophrenia [6, 7]
depression  and
obsessive-compulsive disorder .
This is genetics in action. However, the coming of age of gene editing technologies such as CRISPr/Cas9 may allow for correction of these and other mutations – when no other intervention would fail to work .
Similarly, myelin is damaged by many metabolic disorders, including Canavan, Menke’s, Krabbe’s and Refsum’s disease, and by infection, trauma, toxins (including alcohol), hormonal imbalance and asphyxia. 
Setting aside pathology, Fields  reaches opposing arguments, that further require investigation (sign of good critical thinking!):
If myelination is largely finished in a person’s 20s, however, doesn’t that contradict recent claims that the brain remains plastic throughout middle and old age?
Other experiments suggest myelination continues into our mid-50s but on a much subtler level. 
Fields  also proposes that for skill acquisition to be most efficient, one must start from a young age. This is tricky though because unless you have parents reading the work of researchers like Fields, you would not have the knowledge, determination and initiative to do it on your own. It’s probably why many of us are not geniuses or grown-up prodigies.
Nevertheless, Fields (and I) thinks that adults can still reach mastery – with much more effort than youngsters though:
Of course, old geezers can still learn, but they are engaged in a different kind of learning involving the synapses directly. And yet intensive training causes neurons to fire, so the potential exists for that firing to stimulate myelination. 
Plus, myelination research is far from being set in stone. I wouldn’t be surprised for the research community to obtain similar findings to synaptic plasticity.
Now, before the research field reaches those findings, I’d like to give some actionable steps for the so-called mastery of a skill. These are Daniel Coyle’s steps, which he widely discusses in his book The Talent Code :
To sum up: it’s time to rewrite the maxim that practice makes perfect. The truth is, practice makes myelin, and myelin makes perfect. And myelin operates by a few fundamental principles.
- The firing of the circuit is paramount
I cannot say this better than Coyle :
Myelin is not built to respond to fond wishes or vague ideas or information that washes over us like a warm bath. The mechanism is built to respond to actions: the literal electrical impulses traveling down nerve fibers. It responds to urgent repetition.
Deep and extended practice builds skill. This is how passion arises. You don’t seek your passion. You gradually build it. There’s no magic or romanticism attached to it, no matter how much some would like to delude themselves/us about it. 
- Myelin is universal
Seems like there are situations when one size does indeed fit all.
One size fits all skills. Our myelin doesn’t “know” whether it’s being used for playing shortstop or playing Schubert: regardless of its use, it grows according to the same rules. Myelin is meritocratic: circuits that fire get insulated. If you moved to China, your myelin would wrap fibers that help you conjugate Mandarin verbs. To put it another way, myelin doesn’t care who you are—it cares what you do. 
To give some credit to one of my favorite mentors, Brian Tracy:
Whatever you mind dwells upon, grows into your reality.
And from others:
You are the average of the 5 people you spend most of your time with – this doesn’t have to be in person though.
- Myelin wraps—it doesn’t unwrap
Like a highway paving machine, myelination happens in one direction. Once a skill circuit is insulated, you can’t un-insulate it (except through age or disease). That’s why habits are hard to break. The only way to change them is to build new habits by repeating new behaviors—by myelinating new circuits. 
Charles Duhigg gives numerous arguments to habit formation and habit change in his book The Power of Habit, while Dr. Daniel G. Amen provides insight into habit change with the thousands of brain scans he analyzed in his psychiatry career in Change your Brain, Change your Life.
- Age matters
This is what gives me hope:
In children, myelin arrives in a series of waves, some of them determined by genes, some dependent on activity. The waves last into our thirties, creating critical periods during which time the brain is extraordinarily receptive to learning new skills. Thereafter we continue to experience a net gain of myelin until around the age of fifty, when the balance tips toward loss.
We retain the ability to myelinate throughout life—thankfully, 5 percent of our oligos remain immature, always ready to answer the call. But anyone who has tried to learn a language or a musical instrument later in life can testify that it takes a lot more time and sweat to build the requisite circuitry. 
As we learned, myelination can occur in the brain until later in life. More accentuated during earlier stages, it loses in intensity but it does not cease as we age (according to current research). As suggested by Fields  myelination affects information processing by controlling the speed and synchrony of nerve impulses. The thicker the myelin sheath the better the conductance and velocity of impulse – the better the skill, the closer to mastery.
To end on a positive note, I’ll leave you with a quote from Coyle’s book :
The truth is, practice makes myelin, and myelin makes perfect.
- Fields, R. D. (2008). White matter matters. Scientific American, 298(3), 54-61.
- Coyle, D. (2010). The Talent Code: Greatness Isn’t Born, It’s Grown. Random House.
- Fields, R. D. (2008). White matter in learning, cognition and psychiatric disorders. Trends in neurosciences, 31(7), 361-370.
- Morell, P., & Quarles, R. H. (1999). Characteristic composition of myelin. Accessed on NIH.gov.
- Morell, P., & Quarles, R. H. (1999). The myelin sheath. Accessed on NIH.gov.
- Hakak, Y., Walker, J. R., Li, C., Wong, W. H., Davis, K. L., Buxbaum, J. D., … & Fienberg, A. A. (2001). Genome-wide expression analysis reveals dysregulation of myelination-related genes in chronic schizophrenia. Proceedings of the National Academy of Sciences, 98(8), 4746-4751.
- Tkachev, D., Mimmack, M. L., Ryan, M. M., Wayland, M., Freeman, T., Jones, P. B., … & Bahn, S. (2003). Oligodendrocyte dysfunction in schizophrenia and bipolar disorder. The Lancet, 362(9386), 798-805.
- Stewart, S. E., Platko, J., Fagerness, J., Birns, J., Jenike, E., Smoller, J. W., … & Rauch, S. L. (2007). A genetic family-based association study of OLIG2 in obsessive-compulsive disorder. Archives of general psychiatry, 64(2), 209-214.
- Lander, E. S. (2016). The Heroes of CRISPR. Cell, 164(1), 18-28.
- Schmithorst, V. J., Wilke, M., Dardzinski, B. J., & Holland, S. K. (2005). Cognitive functions correlate with white matter architecture in a normal pediatric population: a diffusion tensor MRI study. Human brain mapping, 26(2), 139-147.
- Bengtsson, S. L., Nagy, Z., Skare, S., Forsman, L., Forssberg, H., & Ullén, F. (2005). Extensive piano practicing has regionally specific effects on white matter development. Nature neuroscience, 8(9), 1148-1150.
Images: adapted from here, here and here