Brain Scans Show Why LSD Makes You Feel One With Nature and Your Self Dissolve

When study participants in a new fMRI study on LSD reported experiencing their sense of self dissolve, a common experience on the psychedelic substance, a remarkable thing happened to their brain scan images: The regions of the brain responsible for higher cognition lit up, suddenly becoming heavily “over-connected” with other networks in the brain that do not normally communicate with one another. Brinson+Banks/Echosight

When psychological research into LSD ground to a halt in the mid-1970s, after the Nixon administration placed the drug in the most tightly controlled substance category, the ability to take pictures of brain activity in real time was still decades off. Now, with LSD research back on the rise and functional magnetic resonance imaging (fMRI) scans a standard tool of brain research, a group of neuroscientists decided to pick up where their predecessors left off. What they found explains why, for centuries, people who have taken psychedelics have reported feeling they're "one with nature" and that the self "dissolved" while on a trip.

When study participants on LSD reported experiencing their sense of self dissolve (what researchers called "ego dissolution"), a remarkable thing happened to their fMRI scans: The regions of the brain responsible for higher cognition lit up, suddenly becoming heavily "over-connected" with other networks in the brain that do not normally communicate with one another. The degree of connectivity correlated with the degree to which the person on LSD told the researchers they were feeling the borders between themselves and the rest of the world blur or fall away completely.

"This could mean that LSD results in a stronger sharing of information between regions" that deal with how we perceive ourselves and how we perceive the outer world, Enzo Tagliazucchi, a neuroscientist who helped lead the study, said in a statement. For example, LSD appeared to trigger the area of the brain associated with self-consciousness, called the fronto-parietal cortex, to connect strongly with areas of the brain that process sensory information about the world outside ourselves—areas that don't normally connect. That interconnectedness may be "enforcing a stronger link between our sense of self and the sense of the environment and potentially diluting the boundaries of our individuality," Tagliazucchi said.

It's important to remember, said Tagliazucchi, that when you've taken LSD and experience your "self" or your ego disappearing, it's an illusion; it's what happens when the brain temporarily reorganizes itself to change our perception. In fact, the brain is doing this all the time—mostly to help make our world comprehensible. For example, the brain filters out the veins that cross in front of the retina of our eyes so we see a clear picture not distorted by the veins. "So when we take psychedelics, we are, it could be said, replacing one illusion [with] another illusion. This might be difficult to grasp, but our study shows that the sense of self or 'ego' could also be part of this illusion," he said.

That may sound like stoner philosophy, but it could be key to new insights about how the brain constructs reality—and, perhaps, why reality appears differently to people with certain mental disorders. Tagliazucchi hopes to extend this research to explore what goes on in the brain while it is constructing alternate realities during a dream state, to see how it compares with the brain on psychedelics.

An image from the study, provided by Enzo Tagliazucchi, shows the effects of LSD and psilocybin (the psychedelic substance present in "magic mushrooms") on the overall connectivity of the human brain. Enzo Tagliazucchi

A paper using the data, published Monday in the Proceedings of the National Academy of Sciences , found that the increased interconnectedness of brain regions while on LSD makes the brain of a tripping adult resemble something like the brain of a baby, which is less impeded by compartmentalization than an adult brain. In the adult brain, networks that control vision, movement and hearing function separately; LSD lifts the barriers between these networks, promoting the unconstrained flow of information between them.

"This also makes sense when we consider the hyper-emotional and imaginative nature of an infant's mind," Robin Cahart-Harris of the Imperial College London, who led the study, told Reuters. "This could have great implications for psychiatry," especially in the treatment of depression or other mental disorders that emphasize negative thought, he said, especially because the "improvement in well-being" appears not to subside after the drug has worn off.