The study appeared in the journal Proceedings of the National Academy of Sciences.
In their findings, published in the peer-reviewed journal Child Development, researchers initiated experiments on 96 children at nine months old.
Such changes in the brain may even also be therapeutic, according to the study published in Cortex.
The study, conducted by researchers at the University of California, highlights continual learning during sleep, crucial in inhibiting the loss of old memories.
The internationally-based coalition of researchers examined more than 19,000 participants as part of the Health and Retirement Study.