What An Acid Trip Reveals About How The Brain Creates Meaning

LSD causes neurological changes that can help us understand how the brain assigns significance to things in the environment.

When tripping on acid, people often say that everyday objects become drenched with deep meaning and significance.

In The Doors of Perception, Aldous Huxley famously wrote of becoming utterly captivated by the folds in his gray flannel pants during his first-ever psychedelic experience.

“I looked down by chance, and went on passionately staring by choice, at my own crossed legs,” the writer and philosopher recollected. “Those folds in the trousers ― what a labyrinth of endlessly significant complexity! And the texture of the gray flannel ― how rich, how deeply, mysteriously sumptuous!”

An enhanced sense of meaning is one of the hallmarks of the psychedelic experience. People who have been under the influence of drugs like LSD, mescaline or hallucinogenic mushrooms often describe finding profound significance in even the most prosaic objects and sensations. LSD dramatically changes the way people perceive the environment and themselves, often blurring the boundaries between the two.

But the brain changes underlying these dramatic shifts in consciousness haven’t been entirely clear.

A University of Zurich study, published recently in the journal Current Biology, traces the effect of heightened meaning-making back to certain important neurochemicals and receptors in the brain that are activated by the drug. The findings highlight what’s going on in the brain to create a sense of personal meaningfulness ― not only during the psychedelic experience, but also in our normal waking consciousness.

“[We now know] which receptors, neurotransmitters, and brain regions are involved when we perceive our environment as meaningful and relevant,” Dr. Katrin Preller, the study’s lead author, said in a statement.

Preller explained that in our everyday lives, attaching personal significance to things ― like songs, friends and household objects ― allows us to experience our environment as meaningful. To investigate the neurobiology underlying this phenomenon, the researchers looked to the LSD state, in which the brain goes into overdrive to find meaning in the environment.

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How The Mundane Becomes Meaningful

For the experiment, 22 participants took a high dose of LSD as the researchers monitored their states of consciousness, perceptions, anxiety levels and moods using the OAV, a standard questionnaire on altered states of consciousness. This confirmed that across the board, the drug typically brought about an enhanced sense of meaningfulness.

Next, the participants were given either LSD, a placebo, or LSD with a drug called ketanserin, which blocks the ability of LSD to act on 5-HT2A serotonin receptors. The researchers wanted to isolate the activity of this particular serotonin receptor ― which is known to mediate the drug’s hallucinatory effects ― to determine whether it was also responsible for enhanced meaning-making.

After the LSD had kicked in, the participants had their brains scanned while they ranked the meaning they associated with a series of songs they had previously described as personally meaningful, neutral or without meaning.

The experiment showed that songs that were previously meaningless to the participants took on special meaning when they were tripping. However, this effect was greatly reduced when the participants took ketanserin along with LSD.

5-HT2A is thought to be the main brain receptor involved in LSD’s consciousness-bending effects. So blocking LSD from altering this receptor also blocked the drug’s effect of enhanced meaning-making, as well as other psychedelic effects. This suggests that these serotonin receptors play a key role in our ability to attribute relevance to things around us, from a song to a constellation in the sky.

“Our study shows that there is a certain network of brain regions involved in the attribution of meaning,” Preller told The Huffington Post.

The same receptor may also play a role in another common effect of LSD: the loosening of self-other boundaries and sense of oneness and interconnection.

But it’s not all positive. Imbalanced stimulation of the receptor can cause an unhealthy attribution of personal meaning to things in the environment, potentially causing paranoia and phobias. It’s likely that this occurs in schizophrenia, which can involve a feeling that people are “out to get you.”

Beyond helping psychedelic enthusiasts better understand their altered states, Preller hopes that her findings will help people suffering from psychiatric disorders, who may be dealing with an imbalanced stimulation of this important receptor.

“It’s important to consider the serotonin 2A receptor as potential target for the treatment of and development of new medication for psychiatric illnesses characterized by alterations in personal relevance attribution,” she said.

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