Sleep After Learning Strengthens Brain Cell Connections, Enhances Memory

In study recently published in Science, researchers report that sleep after learning encourages the growth of dendritic spines. Moreover, the activity of brain cells during slow-wave sleep after learning is critical for such growth. The findings of the animal study conducted at the New York University Langone Medical Center support the hypothesis that sleep helps consolidate and strengthen new memories, and show how learning and sleep cause physical changes in the motor cortex. Researchers used mice genetically engineered to express a fluorescent protein in neurons. Using a special laser-scanning microscope that illuminates the glowing fluorescent proteins in the motor cortex, the scientists were then able to track and image the growth of dendritic spines along individual branches of dendrites before and after mice learned to balance on a spin rod. After documenting that mice sprout new spines along dendritic branches, within six hours after training on the spinning rod, the researchers set out to understand how sleep would impact this physical growth. “Now we know that when we learn something new, a neuron will grow new connections on a specific branch,” says senior investigator Wen-Biao Gan, PhD. “Our data suggest that neuronal reactivation during sleep is quite important for growing specific connections within the motor cortex,” Gan adds. To learn more about this study, click here.