We've got our wires crossed: The bizarre stories of people whose brains have rewired themselves
The human brain is the most complex organ in the body and contains 20 billion cells, responsible for everything from dreaming and movement to appetite and emotions.
It consists mainly of grey matter - the brain cells or neurons where information is processed.
It also contains white matter - the nerve fibres which, like electric cables, send out chemical messengers and relay information between the cells.
In fact, the brain contains more nerve fibres than there are wires in the entire international telephone network and sometimes the brain's 'wires' can become crossed, as a result of injury, illness or genetics.
Scientists used to think a brain injury resulted in permanent damage to the brain's functions, but new research suggests this is not necessarily the case.
'When one area of our brain is damaged we now know from scans that the functions of that area are distributed elsewhere,' says Dr Keith Muir, a senior lecturer in neuroscience at Glasgow University.
'That is why after a stroke people sometimes lose the use of their hand or leg then regain it because another area of the brain eventually takes up the job of movement.'
In fact, says Dr Muir, rather than talking about different areas of the brain it is better to think of it as having numerous different systems which link up and work together.
When the brain is injured, the systems learn to link up differently - sometimes with surprising results.
Some people are actually born with this kind of altered wiring. At birth we all have far more brain cells than we need and as we develop there's a period of so-called 'pruning' - when only the connections and brain cells needed and used survive.
In some cases it's thought that this process goes awry - perhaps because of a faulty gene - resulting in cross wiring or extra connections.
Here, we talk to people whose brains have been 'scrambled' as a result of illness or birth.
But far from being a hindrance, some of them believe it is actually beneficial.
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