Rewiring the brain

Neurons that fire together, wire together

Learning changes the brain

Wiring and rewiring the brain

Advanced technologies that rewire the brain

"When we say that neurons 'rewire' themselves, we mean that alterations occur at the synapses, strengthening and increasing, or weakening and decreasing, the number of connections between the neurons."

When we "change the channel" and refocus on a new activity, we exercise the brain in a new way and grow new circuits.

Norman Doidge in The Brain That Changes Itself

The term "wiring the brain" or "rewiring the brain" refers to changes that occur at the synapses or connecting spaces between neurons. A synapse is the microscopic space between two neurons across which they connect to each other. Neurons can either fire or not fire. They "fire" when they're stimulated and become active.

Axons send or take information away from an activated neuron, and dendrites receive or bring information to a neuron. Electrical impulses or signals travel down the axon of the activated neuron to its axon terminals, where chemicals called neurotransmitters are released into the synaptic space. Neurotransmitters are the chemical messengers that are released from axon terminals of one neuron, and cross a synaptic gap to interact with receptors in the dendrites of another neuron.

Neurotransmitters affect the receiving neuron in one of two ways. They are excitatory or inhibitory. They can either excite a neuron, causing it to fire. Or they can inhibit a neuron, making it less likely to fire.

Canadian behavioural neuropsychologist, Donald Hebb proposed in 1949 that neurons firing together strengthen neuronal connections and pathways. His contribution led to the popular axiom - "neurons that fire together wire together."

Synaptic changes may strengthen and increase, or weaken and decrease, the number of synapses or connections between neurons. Neurons may even create new neuronal pathways or network connections between neurons. For example, in the case of brain damage from stroke, recovery occurs when the brain creates new communication pathways to replace damaged networks.

In other words, neurons "wire" when they regularly connect across synaptic gaps, and along neuronal pathways. They "rewire" when these connections and networks are replaced by others. These synaptic changes are reflected in lasting brain change.

Neuroscientists have contributed other axioms. "Neurons that fire apart wire apart." "Neurons out of sync fail to link." "Use it or lose it." In other words, if neurons are not activated, or co-activated, those synaptic connections and neuronal networks are weakened, and eventually lost.

Recommended Resources

Sharon Begley in Time Magazine - "How the Brain Rewires Itself"

CBC Documentary - Changing Your Mind

Norman Doidge - The Brain That Changes Itself

Jeffrey Schwartz - You are not your brain

The Globe and Mail - Can a controversial learning program transform brains?

Article on Alain Brunet's treatment for PTSD - The Spotless Mind