Magic Mushrooms Warp Our Sense of Space, Time, and Self By Disrupting Our Brain Connections, Scientists Say

Magic mushrooms, fungi with psilocybin, have long been prized across various cultures for their hallucinogenic properties. More recently, their potential to treat intractable conditions like depression, addiction, and anxiety has made them a hot—and controversial—area of research. The key to both uses, says researchers, lies in how the compound disrupts connections in the brain, some of which underpin our perception of self, time, and space.

Building on previous observations of this phenomenon, scientists captured detailed functional magnetic resonance images (fMRI) of the brains of seven healthy adults before, during, and after psilocybin doses—as described in a July 2024 Nature paper. “Our participants were real troopers. They came back time and time again,” says Dr. Ginger Nicol, a psychiatrist at the Washington University School of Medicine in St. Louis, Missouri and one of the study’s co-authors. The repeated scans—which measure real-time brain activity via blood flow—were crucial to establish what each person’s normal looks like and how that picture changes with psilocybin.

Our brains are organized into networks—disparate regions that work together to perform specific tasks. Higher-order networks help us with complex cognitive activities like planning and problem-solving while lower-order networks manage basic functions like vision and hearing. When we take hallucinogens, two things happen. Components within a network “desynchronize and stop firing together in the way that they typically do,” Dr. Nicol says. At the same time, the networks become less distinct from one another—the boundaries between them blurring. “The brain as a whole becomes more chaotic, more [disordered],” says Vitaly Napadow, Ph.D., a neuroscientist at Harvard Medical School and Mass General Research Institute, who was not involved in the study.

The largest changes occurred in the higher-order networks controlling focus and attention, which “help us make sense of and give meaning to physical sensations,” says Dr. Nicol. These changes might explain statements made in the throes of a trip such as “I can feel the trees breathing” or “the grass seems friendly,” she speculates. And the more intense the psychedelic experience—as determined by a participant’s responses to a 30-question mystical experience questionnaire—the more disrupted the brain’s normal pattern of activity became.

Among the higher-order networks, the default mode network—responsible for autobiographical memory, self-reflection, and imagining the future—is particularly sensitive to psilocybin, which acts on that system’s serotonin receptors. Upheaval within this network could explain magic mushroom users’ reports of ego dissolution, or feelings of profound connection to the larger universe.

Evidence suggests that faulty, hyperactive connections within the default mode network also play a role in conditions such as depression and schizophrenia. Psychedelics, by disrupting these connections, might serve as a reset button, allowing the brain to regain normal function in the aftermath.

Dr. Napadow cautions, however, against overinterpreting these observations. “We don’t know for a fact that this disconnection in the default mode network is related to mystical experiences or ego dissolution.” Alcohol, caffeine, and chronic pain are also associated with disruptions in this network, he notes, without tripping.

Other researchers, like Danilo Bzdok, Ph.D., a medical doctor and computer scientist at McGill University, are casting a wider net to characterize the hallucinogenic experience. In a 2022 paper in Science Advances, Bzdok and colleagues used machine learning algorithms to map the effects of 27 psychoactive drugs (psilocybin, MDMA, ketamine) on the brain. They drew on a library of 7,000 first-hand accounts to connect descriptions of each drug experience with that drug’s known action. They found that hallucinogenic experiences play out in many networks, involving many neurotransmitters. For example, “we showed that subjective time dilation and subjective time compression (when it feels like time is passing very slow or is going by very fast) is related to dopaminergic neurotransmitters,” Dr. Bzdok says.

Whatever mechanism is at play, Dr. Napadow would like to see more research with patient populations that investigates the effectiveness of psychedelic-assisted psychotherapy. One project he is currently pursuing looks at how psychedelics, by interrupting the brain’s connections, could make a patient more receptive to ideas from psychotherapy.

Ideally, we would develop a blood test—rather than rely on fMRI scans—to identify these therapeutic windows and help determine “when it’s time to do another psilocybin session,” Dr. Nicol says. She is thinking about the therapeutic implications too.

She acknowledges that we’re still in the early days of linking these experiences with specific changes in the brain and how that affects our sense of self. Ultimately, “these tools are just the first step on the path of really understanding ourselves and our consciousness better,” she says.