Can my brain be filled to capacity? Is it too full to learn more?
No, you cannot use the excuse that your brain is too full to learn
more. Instead of filling up, the brain is a remarkable, plastic structure.
The brain changes constantly so that you can learn, forget, remember
what’s important, and unlearn what you no longer need to know.
When you learn, some of the neurons in your brain generate
dendritic spines. Dendritic spines are little knobs that stick out of
neuronal dendrites. At these knobs, you can find synapses, which are
widely considered to be locations where learning happens at the
molecular level. Synapses are tiny spaces (30-50 nm) between two
neurons, across which one neuron sends a message to the other. It
has been estimated that there are ~86 billion neurons and ~100 trillion
synapses in the human brain.
When neurons communicate more with each other, synapses and
spines are generated or strengthened. When neurons communicate
less with each other, spines can be retracted. The dynamic process of
building and eliminating synapses continues throughout your entire
life. The brain is constantly remodeling itself by inserting new spines
and getting rid of unneeded spines. The ability to remodel based on
learning and experiences is called plasticity, or neuroplasticity.
In the past, people thought brains were like computers because you
learn and store information. However, today we know that the brain is
so much more capable than a computer because a brain remodels itself,
never gets too full, and adjusts to experiential learning. In contrast,
when a hard drive is full, you simply cannot add any new information.
You can delete information to make room for something new, but a
hard drive cannot intelligently decide what is unimportant and okay to
delete on its own.
When we are born, the brain is full of extra synapses and
miscellaneous connections. As a newborn learns and experiences the
world, the brain begins to learn which synaptic connections are
important. The important synaptic connections get stronger, while the
unneeded synapses disconnect and retract. Through this process of
pruning, our brains develop into highly functional adult brains that are
less plastic and more refined for our daily activities.