As we age, the number of grey hairs on our head may increase, but the grey matter inside shrinks. Most people will lose around a tenth of their brain volume, during their adult life, despite most of their brain cells remaining healthy. Neuroscientists studying brains for signs of ageing, have used magnetic resonance imaging to map the grey matter of people dependent on cocaine. They scanned the brains of 60 non-drug-users (left image) and 60 addicts (right image) and found that people addicted to cocaine lost their grey matter twice as fast as those with no history of drug abuse. The areas most affected by shrinkage (shown here in blue) are important for attention span, decision-making and memory, and may explain why long-term cocaine users often look older than their peers and show signs of premature mental decline.
Written by Caroline Cross
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