June 5, 2014
Science Daily/NYU Langone Medical Center / New York University School of Medicine
Researchers show for the first time that 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, the junctions at which brain cells meet.
"Now we know that when we learn something new, a neuron will grow new connections on a specific branch," says 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."
Finally, the scientists showed that brain cells in the motor cortex that activate when mice learn a task reactivate during slow-wave deep sleep. Disrupting this process, they found, prevents dendritic spine growth. Their findings offer an important insight into the functional role of neuronal replay -- the process by which the sleeping brain rehearses tasks learned during the day -- observed in the motor cortex.