So with such a lack of consistent information regarding cannabis' effects, how do we know what to believe? In 2006, neuroscientists Ivan Soltesz and Kevin Staley teamed up in order to attempt to identify any relationship between cannabinoids and memory. This research examined the effects various cannabinoids, such as THC, a phytocannabinoid that is the major psychoactive principle of marijuana, and CP55940, a synthetic cannabinoid, on the CB1 cannabinoid receptors. This type of cannabinoid receptor is the most abundant G-protein-coupled receptor in the brain and has an extremely high density in the hippocampal formation, suggesting a possible link between cannabinoids and memory deficits.
This study found that in vivo, THC depressed hippocampal and neocortical EEGs at several frequencies. This process was then repeated using the synthetic cannabinoid CP55940, which acts as a CB1 receptor agonist, to confirm THC acted as an agonist to the receptor. Similar results were observed, finding that these cannabinoids lessened the power of hippocampal EEG activity in theta, fast ripple, and gamma oscillations. These oscillations play a critical role in several memory functions such as working memory, coordination of neuronal discharges across regions and memory consolidation. These results successfully show a correlation between memory deficits and the binding of an exogenous cannabinoid receptor agonist to hippocampal CB1 receptors. As a control, these trials were repeated, this time preadministering SR141716A, a CB1 receptor antagonist. As expected, the effects of the cannabinoids were successfully blocked.
This research is important for providing the groundwork for future marijuana research, which can be useful in future memory studies as well as studying models of addiction. So, before you go light up that joint, remember not everything you hear about marijuana is a myth: phytocannabinoids in marijuana are associated with memory deficits.
Soltesz, Ivan, and Kevin Staley. "High times for Memory: Cannabis Disrupts Temporal Coordination among Hippocampal Neurons." Natureneuroscience.com. Nature Neuroscience, 2006. Web.
1 Colorado Medical Marijuana Registry