Individuals who have taken psychedelic drugs, such as magic mushrooms or LSD, often report feeling as if they are in a state of enhanced consciousness. Now, researchers from Imperial College London in the UK say they may have found out why; the drugs trigger similar brain activity to what is experienced during dreaming.
The research team, including Dr. Robin Carhart-Harris of the Department of Medicine at Imperial College London, recently published their findings in the journal Human Brain Mapping.
Psychedelic drugs are known to cause hallucinations and distort a person's sense of reality - events that are described as "mind expansion." But exactly how the drugs do this has been unclear.
With a view to finding out, the researchers conducted a new analysis on a study they had previously published in 2012. In the original study, the researchers used functional magnetic resonance imaging (fMRI) to analyze the brain activity of 15 volunteers as they were given psilocybin - a psychedelic chemical found in magic mushrooms - and as they were given a placebo.
Specifically, the team looked at any changes in participants' blood-oxygen level dependent (BOLD) signal, which indicates changes in brain activity.
Psilocybin 'triggers brain activity in network linked to emotional thinking'
In this latest study, the researchers applied a mathematical model to results, called entropy. This allowed them to measure the variability of brain activity in specific brain areas to better determine how psilocybin triggers mind expansion.
Participants who had been given psilocybin - a compound found in magic mushrooms - demonstrated simultaneous activity in certain areas of the brain, including the hippocampus and anterior cingulate cortex, which is usually seen in people who are dreaming.
Results of the study revealed that when the subjects had been given psilocybin, they showed greater activity in the brain network associated with emotional thinking. The researchers note that certain areas of this network - including the hippocampus (involved in memory and emotion) and anterior cingulate cortex (linked to states of arousal) - were active at the same time, which is usually seen in the brains of people who are dreaming.
"I was fascinated to see similarities between the pattern of brain activity in a psychedelic state and the pattern of brain activity during dream sleep, especially as both involve the primitive areas of the brain linked to emotions and memory," says Dr. Carhart-Harris. "People often describe taking psilocybin as producing a dream-like state and our findings have, for the first time, provided a physical representation for the experience in the brain."
Furthermore, the team found that participants who had taken psilocybin showed unsynchronized and disorganized activity in areas of the brain linked to high-level thinking, such as self-consciousness.
According to the researchers, past studies have suggested that for the brain to function normally - that is, at a normal level of consciousness - it must have an optimal number of active networks. Their findings suggest that psilocybin increases the number of active networks, which tips the mind into a "chaotic regime," causing psychological effects, such as a dream-like state.
Dr. Carhart-Harris says that determining exactly how psychedelic drugs affect the brain may lead to better understanding of how they can be used for certain health conditions:
"We are currently studying the effect of LSD on creative thinking and we will also be looking at the possibility that psilocybin may help alleviate symptoms of depression by allowing patients to change their rigidly pessimistic patterns of thinking.
Psychedelics were used for therapeutic purposes in the 1950s and 1960s but now we are finally beginning to understand their action in the brain and how this can inform how to put them to good use."
The researchers conclude that further research is warranted before any solid conclusion can be made from their results regarding how psychedelic drugs affect brain activity.
In 2011, Medical News Today reported on a study suggesting that psilocybin may change an individual's personality permanently, making them more open about their feelings and the way they perceive things.