Scientists explain marijuana short-term memory loss

smoking pot

(CNET) -- Scientists have long been puzzled to explain short-term memory loss that results from marijuana smoking. But while an open-and-shut explanation still remains elusive, a couple of neuroscientists may be getting close.

Writing in the journal Cell, Xia Zhang of the University of Ottawa Institute of Mental Health Research, and Giovanni Marsicano of the University of Bordeaux, France, came up with a working explanation by focusing on a kind of signalling mechanism called astrocytes that previously had only been considered important for protecting neurons.

"Our study provides compelling evidence that astrocytes control neurons and memory," Zhang told the journal Nature. "The supporting actor has become the leading actor."

The scientists carried out a series of experiments on rats, giving them THC, the psychoactive ingredient of marijuana, to come up with a theory about the link between astrocyte signalling and cognitive function

The psychoactive ingredient of marijuana is tetrahydrocannabinol (THC). Using microelectrodes implanted into the brains of anaesthetized rats, the researchers found that the compound weakens the connections, or synapses, between neurons in the hippocampus, a structure that is crucial for memory formation.

You can read the full story about the experiments here.

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    Charles Cooper is an executive editor at CNET News. He has covered technology and business for more than 25 years, working at, the Associated Press, Computer & Software News, Computer Shopper, PC Week, and ZDNet. E-mail Charlie.