The world of psychedelics has long captivated scientists and the public alike, and at the heart of this fascination is psilocybin—the active compound in magic mushrooms. When ingested, psilocybin has a profound effect on perception, cognition, and emotional processing. But what exactly causes these hallucinogenic effects? Understanding how psilocybin interacts with the brain not only sheds light on the psychedelic experience but also opens the door to potential therapeutic applications.
The effects of psilocybin
Psilocybin’s effects can be wide-ranging, altering not only how we perceive reality but also how we feel, think, and relate to the world around us. The compound primarily interacts with serotonin receptors in the brain, particularly the 5-HT2A receptor, which plays a significant role in mood regulation and sensory processing. “Psilocybin affects perception by interacting with serotonin receptors in the brain, particularly the 5-HT2A receptor,” notes Kristie Tse, Founder of Uncover Mental Health Counseling. This interaction can lead to a variety of effects, such as “enhanced visual and auditory experiences,” which often manifest as heightened appreciation for music, vibrant colors, or even a sense of unity with the environment.
Many users describe their experiences with psilocybin as transformative, involving deep self-reflection, ego dissolution, and a sense of connection to a larger whole. These effects have proven to be not just fascinating but also therapeutic in clinical settings. “Psilocybin can induce a state of ‘ego dissolution,’ where individuals experience a loss of self-identity, leading to profound shifts in consciousness,” explains Dr. Ozan Toy, Chief Medical Officer at Telapsychiatry. This dissolving of rigid boundaries between the self and the world around can offer users new perspectives, promoting emotional healing and insights into personal challenges.
How psilocybin interacts with the brain
Once ingested, psilocybin is converted into psilocin, which is responsible for the compound’s psychoactive effects. Psilocin interacts with serotonin receptors, especially the 5-HT2A receptor, triggering a cascade of neural activity that leads to altered perception, mood, and cognition. Dr. Maria Knobel, Medical Director at Medical Cert UK, highlights one of the key effects of psilocybin: “Psilocybin can disrupt the default mode network (DMN), a network of brain regions that is active during introspective activities like daydreaming and self-reflection.” Disruption of this network is particularly beneficial for individuals with depression or anxiety, as it allows them to break free from repetitive, negative thought patterns.
In addition to disrupting the DMN, psilocybin fosters what is known as “dynamic hyperconnectivity.” This means that different regions of the brain, which usually do not communicate much, begin interacting more freely. This hyperconnectivity is linked to the “ego-dissolving experiences and the profound sense of unity and boundlessness often reported by users,” as Dr. Knobel notes. By promoting increased neural plasticity, psilocybin allows the brain to form new connections. Tse mentions that in her work as a therapist, she witnessed “individuals describe transformative experiences during sessions, often reporting increased emotional awareness and insights that guide their healing process.”
Why psychedelics alter perception
One of the most striking effects of psilocybin is the way it alters visual perception. Users often report seeing more vivid colors, intricate patterns, and even full-fledged hallucinations. This is because psilocybin alters the brain’s normal processing of sensory information, particularly in the visual cortex. According to a study published in Molecular Psychiatry, psilocybin increases “self-inhibition of both early visual and higher visual-association regions,” which may enhance top-down connectivity, or feedback from higher cognitive functions to sensory areas. This may explain why the visual imagery seen during psychedelic experiences is often more vivid with eyes closed or in dimly lit environments.
Interestingly, psilocybin may affect our perception by altering how the brain uses “visual priors,” or assumptions based on past experiences that help us interpret sensory data. The Relaxed Beliefs Under Psychedelics (REBUS) hypothesis, introduced by neuroscientists Robin Carhart-Harris and Karl Friston, suggests that psychedelics like psilocybin loosen these priors, allowing for a more flexible interpretation of reality. This loosening of the brain’s predictive coding system may explain the visual distortions and sense of novelty often reported during psychedelic experiences.
Visual phenomena experienced under the influence of psilocybin include synesthesia—a condition where stimulation of one sense leads to the automatic activation of another. For example, some users report “hearing” colors or “seeing” sounds, a testament to how psychedelics alter the brain’s normal sensory integration processes. Deborah Kotob, Director of Pro to Pro, describes how psychedelics act on various points along the visual processing pathway, from dilating pupils to altering the way the brain processes visual information. As Kotob explains, “We see with our brains,” and psychedelics dramatically alter this process.
Advancing psychedelic research
Understanding how psilocybin alters brain activity and perception is not just a matter of academic interest; it has important implications for therapeutic applications. The disruption of the default mode network and the promotion of neural plasticity have shown great promise in treating mental health conditions like depression, PTSD, and addiction. In fact, recent studies have demonstrated that a relatively small amount of psilocybin can lead to long-term positive changes in mood and mental health, with its effects on neural plasticity helping the brain to “rewire itself in beneficial ways,” as Dr. Toy states. “Clinical trials, particularly those involving patients with treatment-resistant depression, have demonstrated that a single session with psilocybin can lead to meaningful and sustained improvements,” says Dr. Knobel, with some studies reporting benefits lasting up to a year. rewire itself in beneficial ways
Researchers like Michael Silver at UC Berkeley’s Center for the Science of Psychedelics are using neuroimaging techniques to observe the real-time effects of psilocybin on the brain, particularly in the visual cortex. “Understanding the actions of psychedelics at a neuroscientific level will generate insights into how they’re working as medicines,” Silver explains. By investigating how psilocybin affects specific brain regions, researchers hope to develop more effective treatments for mental health disorders and deepen our understanding of consciousness itself.
As we continue to unravel the neural mechanisms behind psilocybin’s effects, the therapeutic potential of this compound becomes increasingly clear. From promoting emotional healing to enhancing cognitive flexibility, psilocybin offers a unique window into the brain’s capacity for change. With ongoing research, we are not only gaining insights into how psychedelics alter perception but also how these compounds might reshape the future of mental health treatment.
