In the mid 1900’s brain scientist Donald Hebb brought some lab rats back to his home for a period so his kids could play with them. When he returned the rats back to the lab he found that they learned faster than rats that had remained in cages at the lab. He soon discovered that by interacting with his kids the rats he took home had developed bigger, heavier brains.

Using rats, Hebb had stumbled across what took another 50 years for neuroscientists to agree upon in humans -  that our brains are changed through experience! The old dogma that our brains become fixed early in life has been overthrown. In fact what we now know is that our brains continue to change and ‘rewire’ through experienceinto old age, although at a slowing rate.

What is neuroplasticity?

Neuroplasticity is the general term that describes changes in our brain via experience throughout life. The confirmation of neuroplasticity has killed the old Nature vs Nurture debate. A more correct term seems to be Nature x Nurture where although inborn temperamental factors like how strongly we tend to feel emotions are important, even from before birth our experiences begin restructuring our brain’s structure and functioning.

The principles of neuroplasticity

So how does what happens to us shape our brain?

From the beginning of life our brains respond to experiences by making, changing, or strengthening connections among neurons, which are the basic building blocks of the brain. We produce new neurons throughout life at a slowing rate and with each new experience neurons fire, developing an incredible web of connections of about 100 billion neurons that are connected to an average of 10000 other neurons each!

How it works is that when neurons become activated they connect with other neurons that are activated at the same time. This process led to a famous saying about brains- “What fires together, Wires together.” It is the neurons that become activated the most that survive and thrive. And because neurons fire based on how many connections they have with other neurons, the most important factor in neural survival is to be friendly with other neurons. Only the most social of neurons survive. In a process called pruning those neurons that don’t form friends by making connections with other neurons do not become useful, so they literally shrivel and die. This is the brain’s way of becoming more efficient.

Just like muscles…

A simple way to think about our brain’s plasticity is to compare the process to developing our body’s muscles. When we have physical experiences our muscles strengthen just like neurons strengthen with activity and connection, but when our muscles are not exercised they also shrivel and fade away.

So our experiences throughout life play a major role in the way that our brains develop. This is great news for caregivers looking to positively impact the lives of kids. To look more specifically at how brain changes occur, what elements influence how plastic the brain is, and real life examples of brain plasticity see Neuroplasticity: Mechanisms, Environments, and Examples.