You’re going to a house that you’ve never been to before. At a stoplight you glance at the address and then, when the light turns green, you look for the number. You’re using what is technically called working memory to maintain mental access to the house number.

Many studies have shown that working memory may be improved through intensive training, which is encouraging since aging reduces working memory capacity. There are also neurological and psychiatric disorders that impact working memory.

The neurotransmitter dopamine is known to play a central role in working memory. Researchers asked if intensive mental activity due to training could affect dopamine. Specifically they looked at the concentration of two types of dopamine receptors in the brain. They looked to see if there may be a change in the number of D1 receptors in the cerebral cortex or D2 receptors in subcortical brain regions.

The paper titled “Changes in Cortical Dopamine D1 Receptor Binding Associated with Cognitive Training” was published February 6, 2009 in Science.

Volunteers went through 14 hours of training to improve working memory over a 5 week period. Using brain imaging techniques (functional magnetic resonance imaging) the research team showed that improved working memory was associated with a decrease in the number of available D1 receptors.