Monthly Ed Tip January 2022: Neuroplasticity - What does learning look like on the molecular level

What we know about the brain is changing at a rapid pace and much of what we thought we knew about the brain turns out not to be true or is incomplete.  Some of these misconceptions are more obvious than others.  For example, we used to think the brain did not and could not change.  It turns out nothing can be farther from the truth.  Another misconception was that only parts of the brain are used at any given time and it is silent when we are doing nothing.  Also untrue.  Even at rest and doing nothing, the brain is highly active.  In fact, the brain is more active at night during sleep than during our daily activities.  Lastly, is the persistent and proverbially false belief that we only use 10% of our brain.  Advances in technology such as the fMRI allow us to make these many important discoveries. Read on to find out what learning looks like on a molecular level.

Perhaps the most transformative discovery is that with everything we learn, a new fact or skill, our brain is changed forever.  This is called neuroplasticity.

About 25 years ago the science community thought that after puberty, the only changes made in the brain were negative, such as the loss of brain cells due to aging or as a result of a stroke.  Then studies began to show remarkable reorganization in the adult brain.  Research has shown that all of our behaviors and experiences change our brains.  These changes are not limited by age, and are consistently taking place.

---

John Ratey, associate clinical professor of psychiatry at Harvard Medical School, refers to teachers as literal brain surgeons because when a student learns as a result of their instruction, the brain of the student is physically changed forever.   Or as the Greek philosopher Heraclitus said, “You never step into the same river twice.”

---

So what do the changes in the brain due to neuroplasticity look like?

The brain can change in three very basic ways to support learning.

The first is chemically.  The brain functions by increasing chemical signals between brain cells (neurons) triggering a series of actions and reactions.  These actions transpire during short-term learning as the brain increases the amount or the concentration of chemicals between neurons.  This takes place very rapidly, supporting short-term memory in the form of short-term performance of a motor skill or learning task.

The second way the brain can change to support learning is to alter its structure.  This change results in long-term learning, where the brain structurally changes the connections between neurons, hence the physical structure of neurons are actually changed.  However, these changes take time but ultimately result in permanent improvement in long-term learning and skills.

These processes interact.  For instance, we have all tried to learn a new skill such as learning to play golf or the piano.  We had the experience of getting better within a single session and thinking how easy it is to learn.  Yet upon returning to practice the next day, most of the improvements are lost.  What happened?  In the short term, the brain was able to increase the chemical signaling between neurons, but not undergo the structural changes that is necessary to support long-term memory.  The creation of long-term memories and skills takes time and the chemical changes associated with short-term memory do not directly lead to the physical changes in the neurons that are required for long-term memory.

Structural changes in the brain also lead to the integrated networks of brain regions that function together to support learning, leading to certain brain regions that support specific behaviors by changing structurally or enlarging.  For example, people who read braille have larger hand sensory areas in the brain, while the brain areas of London cab drivers devoted to spatial memories are larger due to the required memorization of the labyrinth of London’s streets which are necessary for passing a mandatory licensing exam needed to drive a London cab.

The third way the brain can change to support learning is to alter its function.  As a brain region is used more frequently, it becomes more excitable and easier to stimulate.  In these areas that become more excitable, the brain shifts in how it is activated resulting in whole networks that are shifted and changed.

In summary, neuroplasticity is supported by chemical, by structural, and by functional brain changes.  They can happen across the whole brain or happen in isolation from one another, but mostly they occur in concert with one another.  Together they support learning and are taking place all the time.