By Navneet A Vasistha
I distinctly remember my first day of swimming class. As an adult of 30 years, I was surrounded by a bunch of kids no more than 8 to 10 years in age. While they gleefully splashed about at the deep end of the pool, I tensed my feet as hard as I could at the shallow end so as to not slip and drown. The instructor glared at me and with the voice of a company commander asked me to let go of the ledge of the pool and attempt to beat my feet and arms in unison to stay afloat.
On my first attempt, I ended up swallowing a mouthful of chlorinated water. Then came second, third and fourth attempts and each met with the same fate. An hour went by and I was glad it was the end of day one.
As a neurobiologist myself, I tried to recount how I could enhance my learning. I poured over Youtube videos and research papers and all of them said the same thing. Learning happens quicker during childhood because the neurons in our brains are eager to make and strengthen new connections. With age, this capability wanes and you end up with the awful taste of chlorine in your mouth.
I decided to keep the lessons going nevertheless and a month passed by and I had made very little progress. Fortunately, work pressures rescued me from the daily embarrassment and I stopped going to the pool completely.
Several months later,
while scouting academic journals for new research, I came across a paper titled “Motor skill learning requires active central myelination”. This piqued my interest for several reasons. From an academic standpoint, it said that in addition to neurons making new connections, it was also necessary for learning new motor skills (swimming, calligraphy, playing tennis etc) that the neurons responsible were ensheathed by myelin.
Myelin, for those who might have forgotten their high-school biology, is a fatty acid-rich wrapping found around the thin nerve fibres (or axons in scientific terms).
In our central nervous system (brain and spinal cord), myelin is produced by cells called ‘oligodendrocytes’. This wrap-around nerve fibre plays several important roles in our brains. Just like the plasticky insulation around the electrical wires in our houses, myelin protects our neurons from getting damaged. In addition, the presence of myelin can also speed up nerve impulses 100 times.
But this was not all that myelin could do.
Researchers had found that successful learning of a new motor skill was accompanied by the formation of new myelin wraps in the brain of mice. Interestingly, when the formation of new myelin was prevented, these mice could no longer learn this skill. This role of myelin is equally important when it comes to humans as well.
When participants performed repetitive movements (intercepting a ball in a virtual reality-based task) and subsequently underwent MRI scans, researchers found that it increased the amount of myelin in brain regions involved in that movement.
More importantly, the results suggested that a slower rate of learning resulted in greater change. In other words, adults could still learn new motor skills as long as they were regular and practised it over a longer period.
Armed with this new information, I signed up once again for swimming lessons. This time, I made sure to give myself enough time in between lessons but not get discouraged and fall off the radar. A few months into the lessons and I was getting better! I could gradually make it half-way and then the whole distance. I hadn’t mastered it yet but I was well on my way. Comparing against where I was a year before, I couldn’t pin point what had changed. Except that I perhaps had a bit more of fat supporting my neurons.
About the author
Navneet A Vasistha is a BRIDGE Translational Excellence Fellow at the University of Copenhagen where he researches how neuronal circuits go awry in autism and schizophrenia.
McKenzie IA, Ohayon D, Li H, et al. Motor skill learning requires active central myelination. Science. 2014;346(6207):318‐322. doi:10.1126/science.1254960
Lakhani B, Borich MR, Jackson JN, et al. Motor Skill Acquisition Promotes Human Brain Myelin Plasticity. Neural Plast. 2016;2016:7526135. doi:10.1155/2016/7526135