For something so familiar to human experience, consciousness is still a mystery.
Each day, people cycle through wakefulness and sleep, from a higher level of consciousness to a lower one.
What’s more, some people alter their conscious experience with drugs such as psychedelics, or have unconsciousness induced by anesthesia.
Researchers have investigated these altered states of awareness in an attempt to understand how consciousness is organized within the brain.
A new Michigan Medicine led study takes a data driven approach and for the first time reveals that psychedelics and anesthetics create “mirror image” patterns of large-scale brain organization, with opposite network features.
The team, led by Rui Dai, Ph.D., and Zirui Huang, Ph.D., of the Department of Anesthesiology and Center for Consciousness Science at Michigan Medicine, analyzed functional MRI data from study participants who were administered psychedelic compounds—LSD, psilocybin and nitrous oxide—and compared them to readouts of MRIs of the brain in a sleeping state or under sedation with propofol.
“In previous literature, each individual drug’s influence on brain connectivity was analyzed separately,” said Dai.
“To our knowledge, no one has systematically assessed these two drug classes to compare network organization compared to waking consciousness.”
Specifically, the team observed that psychedelics increased functional connectivity (how closely two brain regions work together), while sleep and anesthesia reduced it.
The same pattern held for topological integration, meaning how easily information travels across the brain, and for interaction complexity, or the number of different patterns of brain interaction that can be observed.
Overall, these results mean that during psychedelic states, the brain becomes more globally connected, more efficient in communication and more dynamic, while anesthetic states are the opposite.Rui Dai, Ph.D., Department of Anesthesiology, Center for Consciousness Science, Michigan Medicine
Furthermore, their results offer a reliable way to differentiate conscious states using data.
The neural mechanism of consciousness is a longstanding scientific question, adds Huang, who is Director of the Center for Consciousness Science at University of Michigan Medical School.
“We analyze it using drugs because we know they will affect consciousness in some way, but we don’t know how. The mirror-image effect discovered by this study suggests that the integration, efficiency, and complexity of brain activity may be fundamental to consciousness.”
References:
1. https://www.newswise.com/articles/psychedelics-and-anesthetics-create-mirror-image-patterns-in-the-brain
2. https://www.cell.com/cell-reports/fulltext/S2211-1247(26)00
(Newswise/APC)