That the neurons in adult rats could be saved with learning has been known by scientists for years. What they didn’t know was if this would be the case for young rats, which produce two to four times more neurons than adult animals.
When scientists looked at the hippocampus, a portion of the brain associated with the process of learning, after the young rats learned to associate a sound with a motor response, they found that the new brain cells injected with dye a few weeks earlier were still alive.
The cells didn’t survive in rats who failed to learn the new task. Said Tracey Shors, coauthor and professor in the psychology department at Rutgers:
“In those that didn’t learn, three weeks after the new brain cells were made, nearly one-half of them were no longer there. But in those that learned, it was hard to count. There were so many that were still alive.”
The study is important, Shors says, because it suggests that the massive proliferation of new brain cells most likely helps young animals leave the protectiveness of their mothers and face dangers, challenges, and opportunities of adulthood.
“It’s not that learning makes more cells,” says Shors. “It’s that the process of learning keeps new cells alive that are already present at the time of the learning experience.”
Optimal Learning Critical
Since the process of producing new brain cells on a cellular level is similar in animals, including humans, Shors says ensuring that adolescent children learn at optimal levels is critical.
“What it has shown me, especially as an educator, is how difficult it is to achieve optimal learning for our students. You don’t want the material to be too easy to learn and yet still have it too difficult where the student doesn’t learn and gives up,” Shors says.
So, what does this mean for the 12-year-old adolescent boy or girl?
While scientists can’t measure individual brain cells in humans, Shors says this study, on the cellular level, provides a look at what is happening in the adolescent brain and provides a window into the amazing ability the brain has to reorganize itself and form new neural connections at such a transformational time in our lives.
“Adolescents are trying to figure out who they are now, who they want to be when they grow up and are at school in a learning environment all day long,” says Shors. “The brain has to have a lot of strength to respond to all those experiences.”
Curlik DM II, DiFeo G and Shors TJ (2014)
Preparing for adulthood: thousands upon thousands of new cells are born in the hippocampus during puberty, and most survive with effortful learning.
Front. Neurosci. 8:70. doi: 10.3389/fnins.2014.00070
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