magic mushrooms work like meditation? the latest science

Magic Mushrooms

Magic mushrooms have been used since mesolithic times, about 10,000 to 5,000 BCE, for various purposes, including shamanic healing ceremonies.  Mushroom-shaped stones have been found in Mayan  (2000 BCE to 1500 ACE) temple ruins in Guatamela and were prominent in the Aztec culture (1300 to 1500 ACE) where they were referred to as "wondrous mushrooms".  However, despite renewed interest in their therapeutic properties, particularly in psychotherapy, almost nothing was known about how they work in the brain, until now.

A current paper in the prestigious Proceedings of the National Academy of Science, "Neural Correlates of the Psychedelic State As Determined By fMRI Studies with Psilocybin" by Carhart-Harris, et.al from Oxford, Imperial College London, University of Bristol, Cardiff University and University of Copenhagen, is the first to examine how the active material in magic 'shrooms, psilocybin, works in the brain.

In their study, psilocybin was administered intravenously in what would be a "moderate" dose orally and subjects were asked to describe the effects they had and how intense they were.  The results are shown in the bar graph at the left.  The highest rated (most intense and most common) was "I see my surroundings change in unusual ways".



   Experiments were conducted using the latest blood-oxygen level-dependent (BOLD) fMRI technology and arterial spin labeling (ASL) perfusion to determine cerebral blood flow (CBF).   The surprising outcome was that there were significant decreases in CBF in many areas of the brain, particularly the high-level association regions and connector hubs (PCC and mPFC).  These centers have been discussed extensively in earlier blog posts as key centers which are also deactivated in meditation, persistently so with sufficient meditation.

Decrease in PCC blood flow
with psilocybin and placebo

Increase in intensity of psilocybin effects with
decrease in PCC blood flow

The decrease in the PCC blood flow with psilocybin was shown to be very significant compared to the control placebo.  The intensity of the effects of the psilocybin increased as PCC blood flow decreased.



The next critical question was what changes there were in how different critical regions communicate with one another.   The fMRI work on the selfing/meing/doing network, discussed extensively in the Brewer, et. al. blog posting, in studies such as Andrews-Hannah at Harvard in 2010 and in the Farb work at the University of Toronto in 2007, showed that the PCC-mPFC coupling was a/the critical element in the selfing network, which is responsible for the default mode network (DMN).

PCC - mPFC selfing network (top)
replaced by experiential network (bottom)
with meditation

If, in the course of meditation the PCC is significantly deenergized, or if the coupling between the PCC and mPFC is weakened significantly, the DMN, the wandering-mind network constructed with many different "selfing" centers, is replaced by an experiential, "now, now, now" network, described in the Farb work by the PP/LPFC/insula and monitored and controlled by the ACC/LPFC network as described in the Brewer work.

In looking at the coupling between these same two key centers under the influence of psilocybin, Carhart-Harris, et. al. determined the level of connectivity between different centers using fMRI.  Using the mPFC as the reference point, they determined how connectivity between it and the other centers changed after psilocybin was used.

Baseline connectivity with different centers compared to the mPFC.
Orange are strongly connected; blue are weakly connected.
PCC is strongly orange and connected.

The PCC, the large orange area toward the back of the brain (left side) in the diagram at the left, (also shown above in the A diagram) is strongly correlated to the mPFC.  However, when psilocybin is administered, there is a dramatic difference.

After psilocybin administration,
the PCC is now blue/weakly connected to the mPFC

Now the previously well connected (orange) PCC is significantly more weakly connected (blue) to the mPFC, i.e. the core elements of the selfing network have been disrupted with psilocybin, much as they were with meditation.


These findings are consistent with correlations found between the experiences of psychedelics and experienced meditators, particularly for us "self reported persistent non-symbolic" (SRPNS) folk.  In  the previously discussed Jeffery Martin Ph. D. thesis, this is exactly what happened with the Hood Mysticism Scale.  we SRPNS/meditators had the highest average scores of 152 out of a possible 160, but the next highest group to the SRPNS was "psychedelics" with an average score of 150.

It should be no surprise that PCC deactivation would be key in both cases.  The PCC is large and is richly supplied with blood, demonstrating its functional importance.  The PCC typically has a 20% higher metabolism than most other brain regions, yet in the Carhart-Harris study, psilocybin decreased blood flow by up to 20%.   It obviously has a role in high-level constructs such as the self or "ego", but it is also an important connector hub for efficient information transfer in the brain by allowing communication between different regions with the fewest possible connections.  It is not surprising that it has such a profound effect on consciousness.

So what is the "take away" here?   The initial neurochemical route by which magic mushrooms operate  is different from that of meditation, but a/the causative factor of deactivation of key selfing centers is the same.   As many of you know, i have never done hallucinogens, not by choice, but because there was no opportunity before i had my Zen awakening experience, and then they weren't of any interest.  my experiences have been arrived at "just" through meditation.

Anecdotally, the same similarity of effects of psychedelics with persistent non-dual meditators has been observed with peyote/mescaline, ayahuasca/DMT and LSD as with psilocybin.  This is not surprising as they are all serotonergic and thus operate in similar/the same way.

It appears as if the path on which i found myself, meditation, works well as it can be persistent, virtually constant, and "natural", without having to do anything (other than meditate), with no "side effects" or legal issues.  It is, however it manifests for you, useful to realize that at the very least, either hallucinogenics or meditation can take you to very similar, if not the same, experiences.  IME, the persistent peace that passeth understanding, that is beyond mere experiences, that can arise from meditation, is worth whatever it costs.