Cocaine can 'alter the brain within hours' after use

Using cocaine can cause changes in the brain within only a few hours, which could become the beginnings of drug addiction, according to a new study. Memory and learning structures begin to grow within the brain hours after first taking cocaine. These structures develop within the brain's frontal cortex, which is responsible higher functions like decision making.

A new study, published in the journal 'Nature Neuroscience', used animal tests to discover the effects that cocaine can have upon a person's brain. A new technique, using a hi-tech laser scanning microscope, allowed scientists at the University of California at San Francisco to look into the brains of mice whilst they were still living, in order to witness the real-time effects that cocaine has.

Mice were injected with cocaine and scientists observed as, within two hours, their brains began to grow dendritic spines. These twig-like structures serve to connect neurons and create memory pathways. The growth of these spines occurred within the frontal cortex of each of the mice's brains.

Alongside this sudden growth of dendritic spines, the scientists observed a change in the behaviour of the mice. When offered a choice between two different environments, one where a cocaine shot had been administered and one where it had not, the mice began to prefer the environment where cocaine had been administered.

The scientists suggests that this change could be the start of drug addiction, as the growth of the new structures in the brain appear to encourage drug seeking behaviour.

Doctor Linda Wilbrecht, leader of the research, said: "It's been observed that long-term drug users show decreased function in the frontal cortex in connection with mundane cues or tasks, and increased function in response to drug-related activity or information. This research suggests how the brains of drug users might shift towards those drug-related associations."

Doctor Wilbrecht added that the new structures that formed in the brain following the administration of cocaine affect neurons that can bias in decision-making.