Researchers found that the newborn brain cells in young rats that were successful at learning survived while the same brain cells in animals that did not master the task died quickly.
"In those that didn't learn, three weeks after the new brain cells were made, nearly one-half of them were no longer there," said Tracey Shors, professor in the Department of Psychology and Center for Collaborative Neuroscience at Rutgers University.
"But in those that learned, it was hard to count. There were so many that were still alive," Shors said.
The study is important, Shors said, 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.
Scientists have known for years that the neurons in adult rats, which are significant but fewer in numbers than during puberty, could be saved with learning, but they did not know if this would be the case for young rats that produce two to four times more neurons than adult animals.
By examining the hippocampus - a portion of the brain associated with the process of learning - after the rats learned to associate a sound with a motor response, scientists found that the new brain cells injected with dye a few weeks earlier were still alive in those that had learned the task while the cells in those who had failed did not survive.
"It's not that learning makes more cells. It's that the process of learning keeps new cells alive that are already present at the time of the learning experience," said Shors.
Since the process of producing new brain cells on a cellular level is similar in animals, including humans, Shors said ensuring that adolescent children learn at optimal levels is critical.
The study was published in the journal Frontiers in Neuroscience.