Psychedelics can reopen “critical periods” in the brain’s development during which mammals are more conducive to learning new skills, according to a new study that can lead to new approaches for stroke recovery.
Scientists have for long searched for ways to reopen “critical periods” in the brain, when mammals are more sensitive to signals from their surroundings.
These periods of brain development have previously been shown as key in helping birds learn to sing, and humans learn a new language, or relearn motor skills after a stroke, and establish dominance of one eye over the other.
A new study, published recently in the journal Nature, has found that psychedelic drugs are linked by their common ability to reopen such critical periods.
The findings, according to researchers, including those from Johns Hopkins University in the US, point to the potential of psychedelics in treating a wider range of conditions, including stroke and deafness, beyond the beneficial effects of such drugs in treating depression, addiction, and post-traumatic stress disorder.
“There is a window of time when the mammalian brain is far more susceptible and open to learning from the environment. This window will close at some point, and then, the brain becomes much less open to new learning,” study co-author Gül Dölen said.
Researchers previously found that MDMA, a psychedelic drug that arouses feelings of love and sociability, can open a critical period in mice.
Scientists earlier thought MDMA’s prosocial abilities smoothens the way for opening the critical period.
But they were surprised to learn from the latest study that other psychedelic drugs without MDMA’s prosocial properties could also reopen critical periods.
In the new research, scientists looked at the ability of five psychedelic drugs – ibogaine, ketamine, LSD, MDMA, and psilocybin – to reopen the critical period.
These drugs have been tied to the ability to change one’s perceptions of existence and enable a sense of discovery about one’s self or the world.
In the latest study, researchers conducted a behavioral test in adult male mice to understand how easily they learned from their social environment.
The experiment involved training mice to develop an association between an environment linked with social interaction versus another environment connected with being by themselves.
Researchers then compared the time spent by the mice in each environment after giving the psychedelic drug to the mice.
They could observe from the experiment if the critical period opened in the adult mice, enabling them to learn the value of a social environment – a behaviour that is normally learned in mice as juveniles.
The critical period stayed open in mice given the drug ketamine for 48 hours while with psilocybin, the state lasted two weeks, scientists say.
Using MDMA, LSD, and ibogaine, the critical period remained open for two, three, and four weeks, respectively.
“The open state of the critical period may be an opportunity for a post-treatment integration period to maintain the learning state,” Dr Dolen said.
“Too often, after having a procedure or treatment, people go back to their chaotic, busy lives that can be overwhelming. Clinicians may want to consider the time period after a psychedelic drug dose as a time to heal and learn, much like we do for open heart surgery,” she explained.
Scientists believe the new results have important implications for the implementation of psychedelics in clinical practice, as well as the design of novel treatments for various mental illnesses.
