Psilocybin and the Functions of the Brain

A study of psilocybin brain imaging showed unexpected revelation.

Reports from a previous article revealed that some recent interesting studies focused on the impact of the drug psilocybin, a classic psychedelic drug. Scientists have not fully understood the mechanisms of the brain by which psilocybin produces its effects. A recent study made use of brain scanning (particularly, functional magnetic resonance imaging) to show a window into the brain of 30 volunteers with which the drug, psilocybin was injected to reveal what happens during the transition between the regular waking consciousness and the beginning of the drug’s effects (Carhart-Harris et al., 2012). The researchers were amazed to find out that the effects of the drug were related to the decrease in activity in some of the key brain areas, instead of the expected increase. This finding led to the assumptions about the relationship between brain activity and the mystical states experienced when using psychedelic drugs. Nevertheless, the real implications of the results of the study are not clear at all.

In this study, each participant had two brain scans, one after receiving a saline injection, and the other, after receipt of a psilocybin injection. Then a comparison of the effects on brain activity was carried out. After administering psilocybin, the flow of blood in the brain decreased, showing reduced activity. In particular, the most regular deactivation in activity was seen in areas regarded as important network hubs that maintain the connectivity of the different parts of the brain. These areas are the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC). (If you are irritated by neuroscience, please do not stop reading just yet, I will try to simplify the brain science as much as I can). These two areas are known to play very significant roles in self- awareness regulation because they are activated specifically, for instance when people are asked to think about themselves (Wicker, Ruby, Royet, & Fonlupt, 2003). The authors were quite fascinated because, under normal circumstances, these areas show much higher activity than other parts of the brain, however, under the influence of the drug, they exhibited the greatest deactivation. Also, the intensity of the changes of consciousness as reported by the volunteers was the same as the decrease in brain activity experienced. This implies that the higher the degree of decrease in brain activity, the “trip” experienced became more vivid.

The reason psilocybin might trigger reductions in brain activity is unknown, but it is okay to make assumptions. The authors argued that the results are consistent with Aldous Huxley’s idea that natural consciousness behaves like a “reducing valve” which limits the amount of information a person naturally takes in, to prevent one from getting overwhelmed by chaotic impulse. Therefore, the evident “mind-expanding” impact of psychedelic drugs results from a relaxation of this limiting effect. The reduction in the activity of the brains connector hubs might allow an “unlimited cognition style” which produces psychedelic effects (Carhart-Harris, et al., 2012).

In an article for Time Magazine, Carhart-Harris adds more assumptions to this. When psilocybin is administered in higher doses, a lot of people experience a feeling of self-transcendence in which the boundaries of the self, tend to dissolve resulting in an ecstatic state of being united with the universe. As earlier observed, parts of the brain connected with self-awareness, the mPFC, and the PCC, indicated a clear reduction in activity under psilocybin. This could mean that that self-transcendence is induced by reduced activity in these parts of the brain. This idea seems to appeal to people when considering that contemplative traditions target ego-transcendence development when the mind is kept quiet.

However, let us not be in a hurry to conclude yet. There is a potential issue with the interpretation of Carhart-Harris et al. findings which they have failed to consider. Research carried out before has revealed that a lot of some brain areas, including the mPFC and the PCC, normally indicate very high levels of activity when a person is only at rest, and also show decrease in activity when concentration is based on various tasks that are not associated with self-thoughts (D’Argembeau et al., 2005; Wicker, et al., 2003). Even though it is true that this part of the brain are important for self-awareness, easy tasks like looking out of a window or thinking about others can cause a reduction of activity in these areas under normal conditions. In the study of Carhart-Harris et al., the brain activity was compared under the influence of psilocybin and when simply at rest. This is a potential problem because activity in the mPFC and PCC appears to be highest when at rest. So, reduced activity in these areas under psilocybin might only be because volunteers were concentrating on the unfolding hallucinatory experience instead of thinking of nothing in particular. Future research could test this by using comparing conditions where participants are involved in an attentional task instead of just resting. If there are noticeable differences in the intensity of deactivation in the major brain areas, this might be evidence that these specific brain areas play a significant part in the psilocybin experience.

With all these concerns, the idea that psilocybin permits “unlimited cognition style” does not fascinate me. Following the discussions in my previous article, there is a strong connection between the absorption of personality traits and the extent to which a person experiences changes in consciousness under the influence of psilocybin (Studerus, Gamma, Kometer, & Vollenweider, 2012). Absorption relates to likelihood to have unusual ideas and loose connections; this suggests that high absorption is related to a cognition style that is very less limited compared to that of the average person. Also, a study of volunteers who have never taken psychedelic drugs revealed that volunteers who experienced serious mystical experience under psilocybin were exposed to increase in long-term openness to experience (MacLean, Johnson, & Griffiths, 2011), a personality trait that has a close association with absorption. This implies that for certain people, the use of psilocybin could result in a permanent change in their cognitive style, perhaps associated with the intensely “unlimited” style experienced when under the influence of psilocybin.

The research on the effects of psilocybin on the brain function is still new. More research into this area could result in interesting findings of the connectivity of the brain and consciousness.


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