"Marijuana appears to improve the memory and learning abilities of old mice. Scientists discovered low doses of its main psychoactive ingredientcannabinoid THCcan reverse the agerelated decline in cognitive abilities a finding that could lead to scientists figuring out a way of slowing brain aging in humans. Researchers are increasingly examining THC tetrahydrocannabinol for its potential medical benefits. In the U.K. Oxford University recently launched a  million  million program to identify new medical therapies through research into the molecular cellular and systems mechanisms of cannabinoids. Meanwhile the U.S. Food and Drug Administration has now approved several medications derived from THC. Many scientists are currently looking at its potential use as a treatment for neurological conditions including multiple sclerosis epilepsy and Parkinsons disease. In a study published in Nature Medicine httpnature.comarticlesdoi.nm. on Monday researchers led by Andreas Zimmer from the University of Bonn Germany have shown how THC can provide significant benefits to mice when it comes to agerelated cognitive decline. THC interacts with receptors in the brains endocannabinoid system which is involved in many physiological functions including pain mood memory and appetite. Previous research has also shown activity in the endocannabinoid system declines as we get older indicating it plays a role in the progression of aging. To study what effect THC has on the aging brain scientists gave low doses of THC to mice at three different life stagestwo months  months and  months. The latter two groups represented mature and old age. The team carried out three experiments. The first involved a water maze where mice have to learn and then remember how to navigate their way to the end. In a control group mature and old mice performed worse than the young group. However when treated with THC the older groups improved at the task while the young mice fared far worse. The studys authors noted that this was in good agreement with the known detrimental effects of THC on cognition in young animals and humans. Next they created a task where mice had to locate a specific object. Older mice treated with THC performed to the same standard as young mice that had not been given the drug. A third test relating to partner recognition also showed THC led to improved memory in mature and older mice. Together these results reveal a profound longlasting improvement of cognitive performance resulting from a low dose of THC treatment in mature and old animals the scientists write. Further research showed what might cause the improvement with THC appearing to restore hippocampal gene transcription patternsactivity in the brain relating to memory and learningto a similar state seen in young mice. The team argues that while they do not yet know if these findings would be same in humans it could lead to new treatments to prevent cognitive decline in older people Cannabis preparations and THC are used for medicinal purposes they write. They have an excellent safety record and do not produce adverse sideeffects when administered at a low dose to older individuals. Thus chronic lowdose treatment with THC or cannabis extracts could be a potential strategy to slow down or even to reverse cognitive decline in the elderly. Zameel Cader associate professor in clinical neurosciences at Oxford University is involved in the institutions  million cannabis research project. Commenting on the Nature Medicine study he tells Newsweek the paper is very interesting on a number of levels. First of all theres clearly growing interest in the potential therapeutic role of cannabinoids and in this particular case THC on various human conditions he says. This paper is addressing a possible role for that compound in memory and cognition which is relevant to disorders such as Alzheimers and other dementias. He said that while it is important to remember the study was carried out on mouse models the differences in the effect of the drug on younger animals versus older animals tells us a lot about our understanding of the differences between old and young brains. Moving this research forward however will be problematic Testing in humans is going to be difficult. This is a challenge faced by anyone wanting to develop a therapy for a human disorder such as dementia. Human lifespan is very extensive. So the question would be when would be the most appropriate time to give these kinds of medications Over what period of time do you need to evaluate the effects In humans it could be years before an effect is noticed. Finally there is the issue surrounding safety. With a cannabinoid like THC which does have adverse effects in certain individuals there would be worries about the chronic dosing of this kind of medicine. We would need to assess the safety first before going into seeing whether it would improve cognition."