New research from Ohio State University suggests that small, daily doses of marijuana may slow the onset of memory loss and diseases like Alzheimer's, Parkinson's and multiple sclerosis, the Toronto Globe and Mail reported Nov. 20.

Researchers gave rats affected by memory loss small doses of a synthetic compound identical to THC, the main ingredient in marijuana, to activate areas in the brain affected by memory loss. They found that giving the rats the equivalent of one puff of marijuana -- not enough to get high -- activated these brain regions and stimulated new brain-cell formation.

The rats were exposed to the drug, WIN-55212-2, for three weeks, after which the researchers assessed the rats based on a memory test. The rats treated with the compound performed better on the test than those not given the drug, the study authors found. The experimental group also experienced reduced inflammation and more growth of new brain cells.

"We are trying to tease out the positive aspects of this plant," said researcher Gary Wenk, professor of psychology and neuroscience at Ohio State University. "Millions of people have used this plant for thousands of years. There is a lot of evidence that there are some interesting things going on in the brains of these people."

The researchers said they are hopeful that their research may lead to the development of a drug to slow down memory loss in those with a history of degenerative disease in their families. "The model could be used for anyone at risk," added Yannick Marchalant, co-author of the study, "perhaps 20 years before the usual onset of the decline in memory."

The researchers presented their findings at the annual meeting of the Society for Neuroscience.