Region of the brain activated during drugs relapse

US scientists have identified an area of the brain which makes heroin-addicted rats relapse. The study on rats showed that by blocking nerve cells in the region – the medial prefrontal cortex - there were fewer relapses.

The study replicated the idea of an addict relapsing when they returned to the place they previously took drugs. Rats were trained to take heroin in one location, they were then sent to "rehab" in an entirely different location which had different sounds and lighting, here they had no access to heroin.

Once the rats had detoxed they were returned to the original location. Here they demonstrated behaviour consistent with heroin seeking. The scientists then used drugs to inhibit the medial prefrontal cortex area of the brain and recorded that the heroin seeking behaviour decreased.

Dr Jennifer Bossert from the National Institute on Drugs Abuse in the US said "There are two main implications, at a research level we've demonstrated this cause/effect relationship in a specific set of activated neurons."

"In the clinical setting, heroin relapse is different to cocaine relapse so drug relapse is probably caused by different circuits for different drugs, which would have consequences for medication."

She also warned about transferring the findings into humans, saying: "You have to be very careful, you can't. Human addicts are very different to rat models, they're often multi-drug users, they're complex."

The full news item can be read here - http://www.bbc.co.uk/news/science-environment-12505223