Changes in the young brains of humans and primates cause impulsive behavior
Impulsive decision-making is not a growing phase that is unique to teenagers, but is actually experienced by other primates as well.
This life process is directly influenced by changes in the brain structure, primarily in regions that affect self-control. In a new study published by Cell Press, researchers have compared the adolescent brains of humans and macaque monkeys.
“As is widely known, adolescence is a time of heightened impulsivity and sensation seeking, leading to questionable choices. However, this behavioral tendency is based on an adaptive neurobiological process that is crucial for molding the brain based on gaining new experiences,” said study co-author Beatriz Luna.
Structural and functional comparisons have shown that macaque monkeys, like humans, have difficulty controlling their reactive responses during puberty.
“The monkey is really the most powerful animal model that comes closest to the human condition,” explained study co-author Christos Constantinidis. “They have a developed prefrontal cortex and follow a similar trajectory with the same patterns of maturation between adolescence and adulthood.”
According to the researchers, risk-taking and thrill-seeking during this time is not necessarily a bad thing.
“You don’t have this perfect inhibitory control system in adolescence, but that’s happening for a reason. It has survived evolution because it’s actually allowing for new experiences to provide information about the environment that is critical form optimal specialization of the brain to occur,” said Luna. “Understanding the neural mechanisms that underlie this transitional period in our primate counterparts is critical to informing us about this period of brain and cognitive maturation.”
During adolescence in humans, the brain network is undergoing critical changes where redundant and unused neural connections are being pruned, or eliminated. Meanwhile, white matter tracts – which will regulate learning and other functions in the adult brain – are strengthened.
As the adolescent brain is refined, one key aspect is the development of neural activity patterns that allow for the preparation of a response.
“Executive function involves not only reflexive responses but actually being prepared ahead of time to create an appropriate plan. This is the change between the adolescent and adult brain and it is strikingly clear both in the human data and animal data,” said Constantinidis.
Luna explained that it is necessary for humans and animals to have an exploratory time in adolescence because these new experiences are needed to help shape the adult brain.
“It’s important to have this conversation and comparison between human and animal models so that we can understand the neural mechanisms that underlie vulnerability during this time for impaired development such as in mental illness, which often emerges in adolescence, but importantly to inform us on how to find ways to correct those trajectories.”
The study is published in the journal Trends in Neurosciences.
Image Credit: Shutterstock/Pavel Chagochkin