Research into the growth of neurons in the brains of mice at the University of South Florida has led to an unexpected finding: Psilocybin, the psychedelic ingredient of certain mushrooms, might one day help treat post-traumatic stress disorder.
Juan Sanchez-Ramos, a professor of neurology at USF, and a former researcher in his laboratory published their findings this summer in the journal Experimental Brain Research. They were attempting to determine the effects of psilocybin on the creation of new neurons in the brain, which helps learning and the development of short-term memory. It’s a process known as neurogenesis.
Sanchez-Ramos said that in some situations, as when a cancer patient is undergoing chemotherapy, the ability to form new neurons is inhibited.
“One of the important things that we know is that if you destroy the capacity to bring new neurons into being, you will have problems with some aspects of memory,” Sanchez-Ramos said. “One of the side effects (of chemotherapy), besides hair loss … is that you inhibit the birth of new neurons. This can mean memory problems and learning problems.”
He and former Ph.D. student Briony Catlow set out to see if small doses of psilocybin in lab mice affected memory. Catlow is now at the Lieber institute for Brain Development at Johns Hopkins Bioscience Park in Baltimore.
They used a classical conditioning experiment: Mice were introduced into a cubicle. They would hear a tone, then receive a slight shock resembling a static electricity snap, which would lead them to freeze in place.
The researchers then looked for fear conditioning in the mice. How long did it take for them to anticipate the shock after hearing the tone?
The psilocybin did not appear to make a difference in how quickly the mice picked up the fear response. But there was, as Sanchez-Ramos described it, a “serendipitous observation.”
Another measure of classical conditioning is “extinction” — when the tone is sounded but not followed by a shock. How long does it take for the mouse to un-learn the behavior?
The mice that were given the psilocybin doses lost the fear response much faster.
Sanchez-Ramos speculates that perhaps very low doses of psilocybin might help soldiers, for example, recover from PTSD.
Consider how a loud unexpected noise such as a car backfiring might trigger an anxiety episode; might the chemical help that person un-learn the behavior?
Another application might be for drug addicts or alcoholics introduced to an environment — exposed to drug paraphernalia, or entering a bar — that could trigger a relapse. “There’s a lot of classical conditioning with withdrawal symptoms,” Sanchez-Ramos said.