Key Takeaway:
- Adolescent Psychedelic Exposure caused lasting competitive avoidance in adult male rats.
- The drug disrupted coordination between the ventral hippocampus and orbitofrontal cortex.
- Researchers say more studies are needed to determine whether similar effects occur in humans.
Researchers at Ningbo University and affiliated hospitals report that repeated adolescent exposure to the psychedelic compound 25C-NBOMe causes lasting social avoidance in adult male rats by disrupting communication between brain regions involved in social and emotional processing.
Study Finds Lasting Effects After Adolescent Exposure
The findings, published in Nature Neuroscience, show that Adolescent Psychedelic Exposure caused rats exposed to the compound during adolescence to later avoid situations requiring competition for shared resources. Rats repeatedly exposed during adulthood did not show the same behavior.
The researchers used Sprague-Dawley rats and administered 25C-NBOMe repeatedly during either adolescence or adulthood. They then monitored the animals’ brain activity and social behavior to compare the effects of exposure at different developmental stages.
“Psychedelics, known for prosocial effects and therapeutic potential in psychiatry, are often first used during adolescence,” researchers Zhi-Peng Yu, Zhong-Yu Zhang and colleagues wrote. They noted that the long-term effects of Adolescent Psychedelic Exposure on social behavior and related brain circuits remain unclear.
The team found that competitive avoidance was the most prominent behavioral change among several social behaviors examined. The change was not explained by differences in general sociability or social dominance.
Brain Circuit Shows Disrupted Coordination
Researchers also identified changes in the rats’ default mode network, a group of connected brain regions involved in memory, internally focused activity, and aspects of social and emotional processing.
“Multisite recordings revealed disrupted DMN synchrony,” the researchers wrote, identifying reduced theta-band coordination between the ventral hippocampus and orbitofrontal cortex as the strongest predictor of the avoidance behavior.
The ventral hippocampus is involved in memory, emotional processing, and social behavior, while the orbitofrontal cortex contributes to decision-making and evaluating outcomes. The study found that communication between the two regions became less coordinated after adolescent exposure.
The researchers then used chemogenetics, an experimental technique that allows scientists to control specific neural pathways, to test whether the circuit was involved in the behavior.
Activating the pathway connecting the ventral hippocampus and orbitofrontal cortex reduced competitive avoidance in rats exposed to the compound during adolescence. Suppressing the same pathway produced avoidance behavior in rats that had not received the drug.
Findings Highlight Need For Further Research
The results suggest that adolescence may be a period when developing brain circuits are particularly vulnerable to repeated exposure to 25C-NBOMe. The study, however, does not establish that psychedelic exposure produces the same effects in humans.
The researchers studied only male rats, leaving questions about whether Adolescent Psychedelic Exposure could produce similar effects in females. They also said further research is needed to determine whether other psychedelic compounds produce comparable behavioral and neural changes.
The findings add to research examining how psychedelic drugs affect the developing brain. Although some psychedelics are being studied for potential psychiatric treatments, many remain controlled substances worldwide.
Because the experiments involved laboratory animals and a specific synthetic psychedelic, the researchers’ findings should not be directly generalized to human adolescents. Future studies will be needed to determine whether Adolescent Psychedelic Exposure is associated with comparable brain-circuit changes in people.
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