Researchers at Columbia University have revealed a sensitive adolescence that shapes behavior through dopamine function, highlighting the complex effects of stimulant exposure on brain development and underlying psychiatric disorders. **scitechdaily.com
Drugs that block dopamine transporters can be harmful to healthy adolescents but beneficial to those with pathologically low dopamine function.
In a groundbreaking discovery, researchers at Columbia University's Irving Medical Center discovered that puberty is a sensitive developmental period that affects impulsivity, aggression, and dopamine function in mice as adults.
In the process of moving from embryo to adult, organisms go through a sensitive period and their development trajectory is affectedenvironmentfactors. These windows of plasticity often allow organisms to adapt to their surroundings through mechanisms of evolutionary selection.
New findings published in the journal Molecular Psychiatry suggest that exposure to stimulant drugs hijacks this period, rightHealthIt can be harmful in children, but it can also be beneficial in children with pathologically low dopamine function.
The role of the dopamine system.
The dopamine system is key to regulating and shaping adolescent behavior. Dopamine system dysfunction is often associated with adolescent-onset neuropsychiatric disorders, such as attention deficit disorder, depression, and psychosis**.
First, we found that the blockade of dopamine transporters during mid-puberty, i.e., 32 to 41 days after birth, rather than before or after in mice, increased aggression, impulsivity, and behavioral responses to amphetamines in mice. Then we found that dopaminergic neurons were also more active in these animals," said Dr. Darshini Mahadevia, a research scientist at Columbia University's Irving Medical Center (CUIMC), who co-led the study with Dr. Deepika Suri and Dr. Giulia Zanni, who are also CUIMC research scientists.
To test the causal relationship between altered neuronal activity and behavior, the researchers then applied modern genetic tools to artificially stimulate dopaminergic neurons in a behavioral task that measures impulses.
In one such task, the rat is trained to press the lever to receive a reward. Once the rats are proficient in this task, they must learn a new rule – not to press the lever to get the reward. Mice with blocked dopamine transporters during mid-puberty and mice with artificially stimulated dopamine neurons performed poorly at inhibiting lever presses on reward.
In another impulsive task, the rats were asked to choose between a small immediate reward and a large later reward, which wasHumansThe mouse version of the marshmallow test, both evaluating the delay discount. "Once again, both the drug and the direct neuronal manipulation increased impulsive behavior, making the rats choose an immediate small reward over a later large reward," Dr. Suri said.
Understand and ** the meaning of mental illness.
Although there is a long history of research on sensitive periods of brain development, it has focused primarily on the sensory system. As an early recognition of the importance of this fundamental process, Hubel and Wiesel were awarded the Nobel Prize in Physiology and Medicine (1981) in the sixties of the twentieth century for their research on ocular dominance plasticity.
Studying sensitive developmental periods that affect complex behaviors, such as impulsivity and aggression, is novel and will help understand the origins of mental illness, as well as their diagnosis, prevention and**, Dr. Zanni said.
By identifying these 'negative' consequences of juvenile dopamine transporter blockade on mouse brain development and behavior, we are tempted to speculate that juvenile dope exposure in humans also increases aggression, impulsivity, and potential susceptibility to drug addiction later in life. ”
Because the experiments were conducted on wild animals, the findings could not be directly translated into clinically appropriate use of psychostimulants (e.g., attention deficit disorder), but could be more of a chronic recreational use or incorrect prescribing, the researchers said.
Transient exposure to psychostimulants during adolescence may have a potentially corrective effect in disease states resulting from a weakened dopamine system, but this hypothesis needs to be experimentally validated.
Crucially, we believe that understanding the underlying biology is necessary to have a clear risk-benefit assessment of recreational or sexual drug exposure in adulthood," said Dr. Ansolger, senior author of the study.