What is brain plasticity?
Brain plasticity, or neuroplasticity, is the capacity of the brain to change its structure and function in reaction to new information. Our brains do this at all ages. “Plastic” as an adjective means being able to change shape – like warm plastic does.
Brain functions can move from one location in the brain to another. For example, this may happen when the original site is damaged. We call this functional plasticity.
The physical structure of the brain also sometimes changes, for example when the brain learns many new things in a new field. This is called structural plasticity. There is an excellent example of this from London.
In 2006, research showed that London taxidrivers have a significantly larger hippocampus (the rear area in the brain) than London bus drivers. This area is specialised in processing spacial information such as how to find your way. London taxidrivers underwent a multi-year training in which they meticulously learned the streets of their city off head – so not using satellite navigation. Bus drivers know a significantly smaller part of the street network because busses have fixed routes, and used their hippocampi a lot less than the taxi drivers. As a result, their hippocampi had physically grown a lot less than those of the taxi drivers.
‘Use it or loose it’
Brain plasticity is a physical process in which the grey cell matter in our brains actually grows or shrinks – usually physically at a small scale. Connections between brain cells can be pruned or weakened. But they can also be created, refined and strengthened.
Changes in the physical brain express themselves as improvements in our skills and functioning. The reverse is also true when we lose skills and functioning. This can be due to some form of neurological damage. But it can also be due to not using certain connections. Nerve connections which are not used are pruned over time. Just as muscles which are not used are.
For a long time, it was thought that after a certain age this was a one-way process of only being able to lose connections and therefor functioning. Dr. Michael Merzenich and others discovered that new connections can be formed as long as the brain lives.
Neuroplasticity and brain damage
A positive effect of brain plasticity is that brain activity associated with a function can move to another physical location in the brain. Either in the case of a normal event, but often in the case of brain damage and recovery. This is called functional relocation. Dr. Norman Doidge discusses this extensively in his book “The Brain That Changes Itself: Stories of Personal Triumph from the Frontiers of Brain Science”. His folllow-on book “The Brain’s Way of Healing” touches on ABM Neuromovement and the work of Anat Baniel.
An example of functional relocation for instance is when someone whose arm is paralysed due to a stroke learns to use that arm again. Even when the area of the brain responsible for controlling the arm has died off, the function of the arm can be regained as another area of the brain takes over that role.