Accidentally discovered by Swiss chemist Albert Hofmann in 1943, who, after ingesting it, experienced the world’s first acid trip as he cycled home, LSD has garnered a lot of scientific interest in recent years thanks to its potential medical applications.
The psychedelic drug is famous for causing unique “trips” – from the dire to the delightful – but we still don’t really know how it works. Now, scientists are one step closer to understanding exactly how LSD affects the wiring in our brains.
Publishing their findings in the Proceedings of the National Academy of Sciences, a team from the University Hospital for Psychiatry in Zurich and University College London used MRI scans to peer into the brains of 25 healthy people who had taken LSD, comparing what they saw to images of the volunteers' brains after they'd taken a placebo.
The researchers wanted to test an existing hypothesis that suggests LSD causes changes to certain circuitry within the brain, specifically the cortico-striato-thalamo-cortical (CSTC) pathways. They looked at four CSTC-linked brain regions: the thalamus, which relays information; the ventral striatum, which is involved in reward processing; the temporal cortex, which processes sensory information like sound; and the posterior cingulate cortex, which is linked to our sense of self – something weakened by LSD.
“The study is not necessarily the first to investigate connectivity changes induced by LSD,” lead author Katrin Preller told IFLScience. “But it is the first to investigate directed (effective) connectivity specifically in CSTC pathways.”
The team discovered that LSD did indeed alter the connectivity between the CSTC regions. For example, they found that the drug increased the amount of information being passed from the thalamus to the posterior cingulate cortex, while decreasing information flow to the temporal cortex.
“Our results provide evidence that LSD alters directed connectivity within CSTC pathways in humans, suggesting that a disintegration of information processing within these loops is underlying the psychedelic state,” the researchers wrote in their paper.
The authors also note that their findings could help to explain why psychedelic drugs like LSD seem to have antidepressant properties. Previous research suggests that people with major depressive disorder have greater connectivity between the thalamus and temporal cortex. LSD, on the other hand, appears to dampen this connection.
So, might we see LSD being prescribed by doctors in the near future?
“Studies investigating the effects of psychedelics in clinical populations look very promising,” Preller told IFLScience. “However, so far the studies are small and mostly not controlled enough. But larger and better-controlled studies which are currently underway will help to answer this question.”