Can you believe that by using electron microscopes and other types of imaging, scientists have been able to look at the results of learning in the brain?  They have found that knowledge isn't just that invisible batch of information in your brain, but rather a physical thing. 

Just like when you lift weights, you increase muscle mass, so when you exercise your brain, you increase brain mass!  As you learn, the neurons (nerve cells) in your brain grow fibers called dendrites.  These dendrites make connections with other neurons within the brain.

Scientists know this because they have found, for example, that a baby's brain has neurons with only a few dendrites extending from the body of the cells while the brains of older babies have even more dendrites.  (Actually, it's amazing how many dendrites babies put on in the womb.) 

And the dendrites increase as you get older and learn more.  In fact, older people's brains contain such a jungle of matted dendrites, it's been described as similar to the grass roots in turf.  (The word "dendrites" very appropriately comes from the Greek word meaning trees.)

When scientists provided mice with enriched environments (meaning more opportunity to learn), they discovered that the brains of those mice weighed more than the brains of mice raised in sterile environments.

So you can imagine that when you learn anything, your brain is growing more dendrites and therefore, getting heavier!

Here are more examples of dendrite growth.


So how does it work?

In addition to all the dendrites, each neuron has one long tentacle called the axon that ends in more branches, which are called axon terminals or boutons. 

An electro-chemical pulse travels through the axon and out the terminals, jumping a tiny gap called a synapse, and over into the dendrite of another neuron.

Thus the pulse travels across the brain, jumping from brain cell to brain cell.

(Now scientists are figuring out how to see that impulse.  Here are some of the results from patch clamp imaging.)


The myelin sheath serves as insulation, just like the plastic covering on electric wires.  Good thing too, or our brains might short out!

The more dendrites we have, the more directions a thought can go.  It's easier to find or relocate information because you can get to it from so many different directions.


These neurons that form connections are called neuron networks.  The more thorough your learning, the more complicated the networks.  The same information can be found in more than one place in the brain.  This "redundancy" protects the information from being lost. 



Most of this information comes from Rita Smilkstein's book We're Born to Learn:  Using the Brain's Natural Learning Process to Create Today's Curriculum, published by Corwin Press, 2003.

This page was last updated, Tuesday, May 18, 2010, by Connie Gulick.
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