Scientists are studying psychedelic drugs such as psilocybin for mood disorders and substance abuse, and some imaging studies suggest these drugs can reset brain network activity. Because many brain scans use blood flow and oxygen as a sign of neural activity, researchers tested whether those signals remain reliable after psychedelic dosing.
A team at Washington University in St. Louis tested a serotonin-acting psychedelic. In mice given the drug, the normal relationship between neural firing and blood flow was disrupted. When the researchers gave a second medication that blocks a specific serotonin receptor, the unusual blood-flow effects were removed. The team then used psilocybin in more mouse experiments and found similar changes in blood-flow signals.
The group also reanalyzed data from an earlier human fMRI study in people given psilocybin and found comparable effects on brain responses. The work appears in Nature Neuroscience and suggests caution when interpreting blood flow–based neuroimaging after psychedelic dosing.
Difficult words
- psychedelic — a drug that changes perception and mood
- psilocybin — a psychedelic compound found in some mushrooms
- neural activity — electrical and chemical signals in the brain
- blood flow — movement of blood through vesselsblood-flow
- serotonin — a brain chemical that affects moodserotonin-acting
- receptor — a protein on cells that receives signals
- disrupt — to break the normal pattern or processdisrupted
- reanalyze — to look at data again to checkreanalyzed
- neuroimaging — techniques that make pictures of the brain
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How could changes in blood-flow signals affect conclusions from brain scan studies of psychedelic drugs?
- The researchers used both mice experiments and a reanalysis of human fMRI data. Which result do you find more convincing and why?
- If you planned a new study of psilocybin with brain imaging, what precaution would you include based on this article?
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