Marijuana messes up working memory

A team of researchers in France found working memory deteriorates in people who use marijuana. Study leader Giovanni Marsicano of Inserm Research Unit 862 at the University of Bordeaux, in collaboration with a team led by Xia Zhang, identified the mechanism by which compounds found in marijuana leaves and buds affect working memory. The researchers demonstrated the adverse effect of cannabinoids on working memory is exerted via receptors located in the glial cells -- brain cells present in large numbers and scarcely studied. Their study, published in the journal Cell, found the marijuana compounds were associated with a decrease in neural connections in the hippocampus -- the region of the brain that coordinates working memory processes. Working memory is used to perform common cognitive operations such as thinking, reading, writing, calculating, etc. on information stored temporarily -- for periods ranging from a few seconds to a few minutes. This allows for the integration of audio, visual and spatial information, Marsicano explained. Marijuana disturbs this function, preventing the consumer from performing common daily tasks, the researchers said.