THC and other cannabinoids are known to induce neurogenesis — the creation of new neurons — in the brain. There are reasons to believe that this can positively influence diseases like dementia or traumatic brain injury, as well as the ability to learn. Malaysian researchers recently probed the question, does THC improve cognition by inducing neurogenesis? Yes, but only at the right dose. When they applied a dose 6-7 times lower than is commonly used to study THC’s effect on memory, the rats learned from their environment more rapidly and showed signs of neurogenesis in a brain region called the hippocampus. The improvements were even greater after chronic treatment. Unfortunately, these sorts of animal studies are hard to interpret because of the number of factors involved. The results of experiments on THC and cognition may change if the animal is stressed in its learning environment, if mice are used rather than rats, if the dose is given at a different time, etc.