Cocaine 'rapidly changes the brain'

Taking cocaine can change the structure of the brain within hours in what could be the first steps of drug addiction, according to US researchers.

Animal tests, reported in the journal Nature Neuroscience, showed new structures linked to learning and memory began to grow soon after the drug was taken.

Mice with the most brain changes showed a greater preference for cocaine.

Experts described it as the brain "learning addiction".

The team at University of California, Berkeley and UC San Francisco looked for tiny protrusions from brain cells called dendritic spines. They are heavily implicated in memory formation.