Photo: Joe Szilagyi/Flickr CC

The effects of pot on the brain are proving as complex as they are promising, as scientists pull apart the plant’s components…

One new study (its methodology is detailed, below), finds that “CBD did not impair learning but increased adult neurogenesis, whereas THC reduced learning without affecting adult neurogenesis.”

For people suffering from severe depression, this might be good news: The finding here suggests that patients can regain hippocampal cells lost to major depressive episodes. (As the psychedelics expert Sasha Shulgin has pointed out, this is how SSRI’s such as Zoloft appear to work.)

Adult neurogenesis is a particular example of brain plasticity that is partially modulated by the endocannabinoid system. Whereas the impact of synthetic cannabinoids on the neuronal progenitor cells has been described, there has been lack of information about the action of plant-derived extracts on neurogenesis. Therefore we here focused on the effects of delta-9-tetrahydrocannabinol (THC) and Cannabidiol (CBD) fed to female C57Bl/6 and Nestin-GFP-reporter mice on proliferation and maturation of neuronal progenitor cells and spatial learning performance. In addition we used cannabinoid receptor 1 (CB1) deficient mice and treatment with CB1 antagonist AM251 in Nestin-GFP-reporter mice to investigate the role of the CB1 receptor in adult neurogenesis in detail.

via Abstract | Cannabinoid receptor CB1 mediates baseline and activity-induced survival of new neurons in adult hippocampal neurogenesis.