Pathways to Wellness

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Brain basics: a primer

The brain is the most important and the most amazing organ in our bodies.  It’s involved in everything that we think, do, say and feel.  All of our experiences – both positive and negative – influence brain development, particularly in early childhood when the brain is undergoing rapid change.


The brain of a newborn weighs just under half a kilogram, or 400 grams. By 4 years of age, the brain has tripled in weight to 1,200 grams, just 200 grams less than an adult brain.

The brain of a child is a work in progress. Brain development begins during pregnancy but it takes about 25 years to produce a fully formed and functioning brain!  This helps explain the mysteries and perplexing behaviour of adolescents – their brains are still under development.

A baby is born with the same number of brain cells (called neurons) as an adult – about 100 billion.  Everyday experiences shape how the brain gets built.  In the first few years of life, 700 new connections between brain cells (called synapses) are formed every second!   By age 2, the brain of a toddler has 2 times as many connections as their parents’ brains.  Does this make them smarter?  No, just incredibly fast learners! 

Connections that are used become faster and more efficient.  Connections that aren’t used die off through a process called pruning (just like trees and bushes!).  During pruning, as many as 100,000 connections are lost every second.  Pruning begins in mid-childhood and continues through adolescence.

Brains develop throughout one’s life – every time you learn something new or form a new memory, some re-wiring happens.  But it’s never as easy as it is in the first few years of life!  You can take some consolation in knowing that babies’ brains work more slowly than their parents – but they quickly catch up.  Who’s got the fastest brains?  15 year olds hold the record. 

Here are two good videos made by Harvard University on how early experiences build the brain’s architecture and lifelong health and well-being.  The first and shorter video will give you the basics.  Interested in more details?  Watch the second video which is about 5 minutes long.



And here is an easy-to-read booklet on brain development put together by the Canadian Centre of Excellence for Early Childhood Development.

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