Magic mushroom species Psilocybe cyanofriscosa
Credit: Wikimedia
LONDON: The effects of hallucinogenic drugs as they pass through the brain have been mapped for the first time, providing insight into the drug's effects on consciousness and mood.
Psychedelic drugs such as 'magic mushrooms' contain the active compound psilocybin, which causes hallucinations and existential experiences, but until now the causes behind this effect have been unknown.
Publishing in the Proceedings of the National Academy of Sciences today, researchers from the Imperial College London used fMRI techniques to map activity, blood flow and oxygenation in the brains of 30 human volunteers under the influence of either psilocybin or a placebo. They found decreased activity in key parts of the brain that connect surrounding regions responsible for connectivity and information flow across the brain.
"Psychedelics are thought of as 'mind-expanding' drugs so it has commonly been assumed that they work by increasing brain activity," said co-author and neuropsychopharmacologist David Nutt.
"But surprisingly, we found that psilocybin actually caused activity to decrease in areas that have the densest connections with other areas. These hubs constrain our experience of the world and keep it orderly. We now know that deactivating these regions leads to a state in which the world is experienced as strange."
How psilocybin makes you feel
Volunteers were also asked to report how the psilocybin made them feel, which included experiencing visions of geometric patterns, unusual bodily sensations and an altered sense of space and time.
These feelings were shown to be synonymous with decreases blood flow and oxygenation in these regions of the brain, namely the medial prefrontal cortex (mPFC) and the anterior and posterior cingulate cortex. The greater this decrease, the more intense the volunteers reported the effects of the drugs to be.
The mPFC is also known to be hyperactive in depression, which potentially explains the anti-depressant effects felt by users after a reduction in this hyperactivity. "Previous studies have suggested that psilocybin can improve people's sense of emotional well-being and even reduce depression in people with anxiety," said lead author and neuropsychopharmacologist Robin Carhart-Harris from the Imperial College London. "This is consistent with our finding that psilocybin decreases mPFC activity, as many effective depression treatments do."
A therapeutic tool?
Psychedelic drugs have harboured hopes as potential psychotherapy agents in the past, but because the mechanisms behind their effects on the brain were unknown, such applications were limited. This new insight into the changes in brain activity initiated by psilocybin could enable therapeutic applications in the future.
"These results strongly imply that the subjective effects of psychedelic drugs are caused by decreased activity and connectivity in the brain's key connector hubs, enabling a state of unconstrained cognition," the researchers said. "The effects need to be investigated further, and ours was only a small study, but we are interested in exploring psilocybin's potential as a therapeutic tool".
However, the findings aren't as straight-forward as using psilocybin as a treatment for conditions such as depression. "Just because some region has been shown to be active during some task or circumstance does not mean that whenever we see that region activate, those same processes are necessarily taking place," commented Phillip Corlett, assistant professor of psychiatry at Yale University in the U.S. "Nevertheless, this study is an intriguing new insight into how the brain can be coaxed to misrepresent the world and, while much more work is needed to establish the mechanisms, both cognitive and neurochemical, this work provides a very exciting new platform from which to begin that work."
Natural vs Synthetic
UK’s government has yet to be impressed with the magic of mushrooms and continues to classify them as a Schedule 1 controlled substances with no currently accepted medical use. Something one could argue bears very well with most established drug manufacturers who have every incentive to continue demonizing natural psychedelics as they pump up their own synthetic and highly profitable depression drugs.
http://scallywagandvagabond.com/2012/01/ex-government-drug-advisor-fired-for-his-views-on-psychedelics-now-argues-main-ingredient-of-magic-mushrooms-may-help-with-depression/