Effects of Psilocybin and Other Selective Serotonin Agonists on Hippocampal-Dependent Learning and Neurogenesis

Aberrations in brain 5-HT neurotransmission have been implicated in psychiatric disorders including anxiety, depression and deficits in learning and memory. Many of these disorders are treated with drugs which promote the availability of 5-HT in the synapse. However, it is not clear which of the 5-HT receptors are involved in behavioral improvements and neurogenesis. The delay in the appearance of anti-depressant effects of SSRIs corresponds to the time required to generate new neurons. The current study evaluated the effects of the acute and chronic administration of 5HT2A agonists psilocybin and 251-NBMeO and the 5HT2A/C antagonist ketanserin on hippocampal neurogenesis. Chronic administration of psilocybin increased the number of new neurons in the dentate gyrus while the antagonist suppressed hippocampal neurogenesis, suggesting that the 5HT2A receptor appears to be involved in the regulation of hippocampal neurogenesis. Another goal of the study was to investigate the effects of psilocybin, a 5HT2A receptor agonist on hippocampal-dependent learning. All mice developed contextual and cued fear conditioning; however, mice treated with psilocybin extinguished the cued fear conditioning more rapidly than saline treated mice. Interestingly, mice given the 5HT2A/C receptor antagonist ketanserin showed less of cued fear response than saline and psilocybin treated mice. Future studies should examine the temporal effects of acute and chronic psilocybin administration on hippocampal-dependent learning tasks.

This video is from Psychedelic Science in the 21st Century, a conference taking in place in San Jose, California on April 15-18, 2010. The conference was organized by the Multidisciplinary Association for Psychedelic Studies (MAPS) in collaboration with the Heffter Research Institute, the Council on Spiritual Practices, and the Beckley Foundation.

This video was produced by Teal Sievers of Living Dream Films (livingdreamfilms.com).

This video was produced by Green Fuse Media, contact Nathan at greenfusefilms@gmail.com

To learn more about MAPS or to support our work, visit maps.org.

Loading more stuff…

Hmm…it looks like things are taking a while to load. Try again?

Loading videos…