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Getting some sleep after learning encourages the growth of dendritic spines - the tiny protrusions from brain cells that connect to other brain cells and facilitate the passage of information across synapses - according to a new study.

Further the study noted that the activity of brain cells during deep sleep, or slow-wave sleep, after learning is critical for such growth. 

The findings, in mice, resonate with the hypothesis that sleep helps consolidate and strengthen new memories. The study also shows how learning and sleep cause physical changes in the motor cortex - a brain region responsible for voluntary movements. 

"We've known for a long time that sleep plays an important role in learning and memory. If you don't sleep well you won't learn well," said senior investigator Wen-Biao Gan, PhD, professor of neuroscience and physiology and a member of the Skirball Institute of Biomolecular Medicine at NYU Langone Medical Center, in the press release. 

"But what's the underlying physical mechanism responsible for this phenomenon? Here we've shown how sleep helps neurons form very specific connections on dendritic branches that may facilitate long-term memory. We also show how different types of learning form synapses on different branches of the same neurons, suggesting that learning causes very specific structural changes in the brain."

Researchers experimented on mice where they observed that brain cells in the motor cortex that activate when mice learn a task, reactivates during slow-wave deep sleep. 

"Now we know that when we learn something new, a neuron will grow new connections on a specific branch," said Dr. Gan. "Imagine a tree that grows leaves (spines) on one branch but not another branch. When we learn something new, it's like we're sprouting leaves on a specific branch."

The findings of the study provide an important insight into the functional role of neuronal replay - process by which sleeping brain rehearses tasks learned during the day - observed in the motor cortex, the press release added. 

"Our data suggest that neuronal reactivation during sleep is quite important for growing specific connections within the motor cortex," Dr. Gan added in the press release.

The research has been detailed in the journal Science.