In the new study, the scientists inhibited actin polymerization - the creation of large chainlike molecules - by blocking a molecular motor called myosin II in the brains of mice and rats during the maintenance phase of methamphetamine-related memory formation.
Behavioural tests showed the animals immediately and persistently lost memories associated with methamphetamine-with no other memories affected.
In the tests, animals were trained to associate the rewarding effects of methamphetamine with a rich context of visual, tactile and scent cues.
When injected with the inhibitor many days later in their home environment, they later showed a complete lack of interest when they encountered drug-associated cues. At the same time, the response to other memories, such as food rewards, was unaffected.
The study has been published online in the journal Biological Psychiatry.