Psychedelic mushrooms have been used for medical, ceremonial and spiritual purposes for thousands of years, due their mind-alterating properties which induce hallucinations, perception disorders or altered states of awareness. It’s been found that the active ingredient responsible for the psychedelic state, which many associated with a religious experience, is a substance called psilocybin. Though a lot is known about the substance, chemically-wise, how exactly it affects the brain remained unclear until now, but a recent studying involving fMRI brain scans changed all that.

Scientists at the  Neuropsychopharmacology Unit at Imperial College London, used blood-oxygen level dependent (BOLD) functional MRI (fMRI), in conjunction with a technique that images the transition from normal, conscious state to psychedelic state, to scan the brains of volunteers. These were separated into two groups, the ones which were administrated with active psilocybin, and those who were given a placebo.

Decreased cerebral blood flow (CBF) after psilocybin imaged by fMRI

What the researchers found was a decreased blood flow and BOLD in the thalamus, anterior and posterior cingulate cortex, and medial prefrontal cortex. These areas of the brain are key connector hubs, which when faced with a decreased activity, enable a state of unconstrained cognition, which would explain the psychedelic effect.

The study, though highly successful, wasn’t without hardship. Lead researcher Dr. Robin L. Carhart-Harris recalls how a number of impediments made their research one big tough nut to crack. For instance, an exact dosage and delivery protocol was necessary for accurate fMRI imaging, insulating placebo effects like pre-administration anxiety, and a number of other issues, which were fortunately resolved by the scientists.

Now that the exact regions of the brain where the psychedelic substance is active have been pinpointed, research which might lead to beneficial psychedelic drug therapy will not only commence soon, but will be taken more seriously by the rest of the community, as hard evidence of key receptors and their interaction with substances are presented. Psilocybin therapy might help a great deal people suffering from depression.

 “Psilocybin decreases brain activity in regions such as the medial prefrontal cortex,” Dr. Carhart explains, “that are overactive in depression.”

In addition to depression, Carhart-Harris observes, there are other research and applications that might benefit from the team’s findings.

“Those suffering from cluster headaches,” he notes, “report excruciating pain that is difficult to treat, sometimes describing it as worse than the pain childbirth. During such headaches, they show an increase in hypothalamic activity to date has only been ameliorated by deep brain stimulation. However,” he concludes, “when administered psilocybin, they display a decrease in hypothalamic activity and a corresponding suspension of cluster headaches.”

The findings were reported in the journal PNAS.

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