Scientists hoping to allow users of medical marijuana to avoid the impairment of short-term memory that typically goes along with the drug have made a dramatic breakthrough in the understanding of how memory functions.

According to Scientific American, Giovanni Marsicano and his colleagues at the University of Bordeaux in France removed cannabinoid receptors from neurons in mice, then fed them THC, the primary active ingredient in marijuana. The mice turned out to do just as badly at remembering the location of a hidden platform in a pool as regular stoned mice.

The researchers then removed the cannabinoid receptors from the astrocytes surrounding the neurons -- and suddenly the stoned mice were memory whizzes.

Astrocytes are a form of glial cells, which were once thought to serve only as scaffolding and "glue" to keep neurons in place. Recent studies have connected the glial cells with many unconscious processes, but this is the first experiment to show they also play a major role in conscious thought.

“It's very likely that astrocytes have many more functions than we thought,” Marsicano says. “Certainly their role in cognition is now being revealed.”

The pain-relieving properties of THC appear to work through the neurons and not the glial cells, so it may prove possible to separate those properties out from the effects on memory. However, there's no word yet on which kinds of cells are responsible for getting you high.

Photo from Laurie Avocado [CC-BY-2.0 (], via Wikimedia Commons