UC Berkeley’s Center for the Science of Psychedelics (BCSP) has launched a first-of-its-kind study to examine how psilocybin influences visual perception. Although the psychedelic substance has been frequently studied for its potential to treat various mental health conditions, not much is known about its specific effects on the brain’s visual processing. Researchers hope to gain a better understanding of its mechanisms by using human subjects and neuroimaging techniques.
Study overview
Participants will ingest psilocybin and then perform visual tasks while their brain is monitored using functional magnetic resonance imaging (fMRI). This would allow researchers to observe the real-time changes that occur in the visual cortex, one of the most well-understood parts of the brain.
“We have this incredible opportunity to characterize the psychedelic experience in real time — while it’s happening — using modern neuroimaging methods,” explained Michael Silver, the director of the BCSP and the lead investigator of the study. “Understanding the actions of psychedelics at a neuroscientific level will generate insights into how they’re working as medicines and will hopefully help us develop more effective treatments for mental health disorders. It will also shed light on some of the fundamental mysteries of the human brain, mind and consciousness and how they relate to each other.”
Current scientific understanding of psychedelics
While our current knowledge of psychedelics is limited, scientists have deduced that the substances interact with serotonin receptors in the brain, primarily the 5-HT2A receptor, which plays a major role in our visual processing. Many people who do psychedelics often report seeing more enhanced colors, patterns, and visual distortions, yet it is still unknown exactly how these changes occur on a neural level. By focusing on the visual cortex, researchers can use the existing knowledge about this region of the brain to gain more insight into the broader cognitive and therapeutic effects of psychedelics.
Visual priors and the REBUS hypothesis
Human vision is an incredibly complex process, considering it has much to do with how our brains construct our perception of the world. Scientists believe that the human brain combines limited sensory information from the eyes with previous experiences to generate our conscious experience of the world around us. This process, known as visual priors, allows us to fill in gaps and ambiguities in sensory data so we can perceive a stable and coherent environment.
The Relaxed Beliefs Under Psychedelics (REBUS) hypothesis, introduced by neuroscientists Robin Carhart-Harris and Karl Friston, might help explain why psychedelics like psilocybin alter our perception so profoundly. According to the hypothesis, psychedelics work by loosening the deeply engrained beliefs, or priors, that the brain utilizes to interpret sensory information. As priors relax, it allows for a more flexible and open-minded approach to stimuli interpretation, which could be the reason psychedelics produce such vivid and altered perceptions.
By testing out this theory, the BCSP study could find more concrete evidence on how psilocybin and other psychedelics help reframe deeply ingrained patterns of thinking, which can be especially relevant for therapeutic applications. If psilocybin actually leads to a more adaptive interpretation of reality, it could be an incredibly useful tool in treating conditions like depression, anxiety, and PTSD, which involve rigid and negative thought patterns.
Navigating the complexities of human psychedelic studies
Previously, all UC Berkeley studies on psychedelics have been limited to animal subjects. However, after a three-year process, the human participant study finally complies with campus, state, and federal regulations. Now that all requirements are met, it should not take as long to obtain permission to conduct more human studies in the future.
“The preparation needed to be able to conduct psychedelics research in human subjects at Berkeley for the first time has been more than ten times as much work as preparing to do similar experiments involving pharmaceutical drugs that are not controlled substances,” said Silver. “But I think that the infrastructure that we’ve built is going to be very helpful for future human neuroscience studies of psychedelics in the BCSP.”
The study is now accepting volunteers, with the first participants already being screened.
If you are interested in participating or learning more about the study, contact the BCSP Research Staff at [email protected].
