In a new study, researchers have shown that a single dose of psilocybin, a psychedelic compound with potential applications for depression, prompted long-lasting increase in connections between neurons in mice.
For some people, psilocybin, an active compound in ‘magic mushrooms’, can produce a profound mystical experience. The psychedelic was a staple of religious ceremonies among indigenous populations of the Americas and is also a popular recreational drug. It has been the subject of some interest in treating depression. But exactly how it works in the brain and how long beneficial results might last is still unclear.
“We not only saw a 10% increase in the number of neuronal connections, but also they were on average about 10% larger, so the connections were stronger as well,” reported senior author Alex Kwan, associate professor of psychiatry and of neuroscience at Yale.
Earlier work had found promising evidence that psilocybin, as well as the anaesthetic ketamine, could decrease depression. This new study found that these compounds increase the density of dendritic spines, which are small protrusions found on nerve cells which aid in the transmission of information between neurons. The number of these neuronal connections are known to be reduced by chronic stress and depression.
Prof Kwan and first author Ling-Xiao Shao, a postdoctoral associate, imaged dendritic spines in high resolution with a laser-scanning microscope, and tracked them for multiple days in living mice. They found increases in the number of dendritic spines and in their size within 24 hours of administration of psilocybin. These changes were still evident a month later. Also, mice subjected to stress showed behavioural improvements and increased neurotransmitter activity after being given psilocybin.
It may be the novel psychological effects of psilocybin itself that spurs the growth of neuronal connections, Kwan said.
“It was a real surprise to see such enduring changes from just one dose of psilocybin,” he said. “These new connections may be the structural changes the brain uses to store new experiences.”
Source: Yale University
