Your ego disappears, you feel united with the Universe, you see things which are not there and your time perception is distorted: Even if you’ve never taken drugs these effects sound familiar to you; this is what your friends told you after they took acid at some festival or after their recent trip to Amsterdam.
Prehistoric art suggests that psychedelic drugs have a pretty long relationship with humans, their usage in spiritual and healing rituals going as far back as about 5000 years (our ancestors knew what’s up). However, due to political mostly than scientific reasons, psychedelic research was prohibited not long after blooming in the 1960’s and 1970’s. Currently, what can be called a reneissance in the research of psychedelic substances is taking place as more and more scientists turn their attention towards the neural correlates of the fascinating altered states of consciousness associated with psilocybin (the main component of magic mushrooms), ayahuaska and LSD.
So what do these substances do exactly to our brain and how do they do it? Let’s go step by step.
1) TL;DR: Hyperconnectivity.
On psychedelics our brain becomes hyperconnected. Regions which are only weakly or not at all communicating in the normal state of consciousness now show significantly increased connections with each other. Imagine it like this: Different areas in our brain can be understood as various districts of a city. Normally there are guards on the roads not letting certain cars pass to certain districts. Yet after the administration of psylocibin the guards are abolished and the traffic between all the city regions increases immensely — people from each district use the opportunity to visit every place they were prohibited to go before. This way the brain reaches a state of a higher entropy — entropy being themeasure of the randomness of a system in this case. It means that there is an increased number of patterns of activity that are possible; a much larger range of potential brain states you could enter. Take psychedelics, they said, it will lead to a mind expansion, they said.
Consider the following example: Normally, activity in the visual areas of the brain is primarily driven by the visual input. However, on acid the connection between the visual networks and the networks responsible for introspection and day-dreaming is significantly strenghtened. This could cause inaccurate visual percepts and an increased influence of imagination on the visual processing. This might be the explanation for the hallucinations you see with your eyes open and closed. This is a very simplified but a very pretty illustration of what I just said from a study investigating it with very complex mathematical methods I don’t really understand (‘a’ being the sober state and ‘b’ being the psychedelic state).
2) TL;DR: Break-down within networks
There are networks in our brain which are thought to maintain our sense of self, to filter our sensory experiences and to ground them in reality. As you might have guessed, on acid they fail to keep up their integrity and become disintegrated. Psychedelics inhibit brain’s filtering mechanism and allow the senses to run free: The mechanisms working on keeping the world predictable and stable fail and that the previously inhibited background noise gains importance. If sober this crack on your wall merely slightly resembled a spider then on acid — when nothing restricts your perception with knowledge or expectations — you might see a huge black widow step-dancing (sorry I couldn’t think of a more positive example). Also as normally very active regions keeping your ego stable become disconnected you might experience an ego-dissolution, sense of the unity with the Universe and sign up for a hippie camp.
3) TL;DR: Soon, a doctor will prescribe you LSD. Maybe.
It is a safe bet that an average person would not say “cure for mental diseases”, “ or “psychiatry” if asked for the first associations with drugs. However, current research suggests that psychedelics might be very well used in treating various mental disorders: There are studies showing positive effects of psychedelics on addiction, cancer-related anxiety and depression. Moreover, they silence the area which is hyperactive in depression and anxiety and this way prevent people from ruminating and getting caught in bad thoughts about themselves. This means they are very likely to soon be competing with the traditional antidepressants. “Can I get some acid, doc?” might soon not be as unrealistic as you think!
In the end I would like to quote Robin Carhart-Harris, one of the leading researchers on the topic and my current scientific crush right now, because what he says is BEAUTIFUL and FASCINATING:
“One hypothesis is that what you’re actually seeing is the functional organization of the visual cortex itself. The visual cortex is organized in a sort of fractal way [it repeats the same patterns in different sizes]. It’s the same way that fractals are everywhere in nature. Like tree branches, the brain recapitulates [itself],” says Carhart-Harris. “You’re not seeing the cells themselves, but the way they’re organized — as if the brain is revealing itself to itself”.