Everyone knows that practice makes perfect. Throughout life we learn new motor skills and improve upon them as we grow. It seems common sense that practicing a particular task results in increased performance over time, but have you ever stopped to wonder how exactly that happens? An immense amount of research has gone into trying to find out how the brain learns and develops motor skills. Much of this research focuses on two areas of the brain known as the primary motor cortex (M1) and the primary somatosensory cortex (S1). The M1 works with other parts of the brain to plan and execute motor movements as where the S1 gives us our sense of touch and relays information about joint position and movement. These two areas are part of a larger region called the cerebral cortex, which is the highly folded outer layer of the brain that plays a key role in memory, language, and consciousness. The M1 and S1 are located next to one another along a main fold of the brain called the central sulcus which stretches from ear to ear over the top of the brain.

Our brains are composed of a complex system of integrated brain cells called neurons. These neurons carry charges and convey information to one another via electrical transmission. An analogy for this would be that they work similar to computer wiring, where wires convey information in the form of electricity. These neuron systems make up areas of the brain such as the M1 and S1, and can be broken down further into regions of grey matter and white matter.  Using the computer analogy again, the gray matter can be thought of as the informational processors, whereas the white matter makes up the cables connecting the processors together. Grey matter contains the central cell bodies of neurons and appears greyish in colour. The white matter contains neuron fibers called axons (our bodies’ wires) and appear white due to a fatty substance called myelin that surrounds them. This myelin acts in similar fashion to the rubber seen in modern electrical wires which helps to insulate current.

Most studies to date have focused on how grey matter changes in response to improvement upon motor skills. However, very little is known about how the corresponding white matter changes. A research article that was published recently aims to address this issue. In this study mice were split into three groups: An SR group where mice were able to successfully reach through the bars of their cage to retrieve a sugar pellet, A UR group where mice unsuccessfully reached for a sugar pellet that was out of reach, and a CC group where mice did not reach for anything. Each group received sugar pellets initially. SR and UR mice were trained on the single-pellet reaching task for 15 minutes daily for 11 days. The UR mice could never successfully reach the pellet but were rewarded with one for every five attempts they made.

You may ask yourself what the significance of mice reaching for sugar pellets is. Well, after the testing was complete, the researchers examined the M1 and S1 white matter areas of the three mice groups. The SR group showed increased amounts of myelination in the axons associated with fine motor movement of the paws. This showed that practice of motor activity lead to increased amounts of myelination; therefore those axons would become better insulated and send stronger electrical transmissions. The SR group showed more myelination then both the UR and CC group meaning that the actual practice of handling the sugar pellet and not just random movement of the paws lead to increased myelination.

Studies in the past have shown that neurons increase connectivity in response to learning; in other words they make more network connections with one another as motor skills develop. This study differs from others in that it shows that the neurons themselves can change structurally in response to learning.These findings lend us insight into how professional athletes become good at sport. It can also help us to develop better rehabilitation programs for people who have damaged white matter regions of the brain.

Source: Sampaio-Baptista, C., Khrapitchev, A.A., Foxley, S., Schlagheck, T., Scholz1, J., Jbabdi, S., DeLuca, G.C., Miller, K.L., Taylor, A., Thomas, N., Kleim, J., Sibson, N.R., Bannerman, D., & Johansen-Berg, H. (2013). Motor Skill Learning Induces Changes in White Matter Microstructure and Myelination. The Journal of Neuroscience, 33(50), 19499-19503.