New Delhi: A new study explains a possible reason why taking a nap break sometimes helps people perform better when they resume a task — during sleep, short-term information related to the task at hand is converted into long-term, stronger memory, researchers have found.

The team, led by researchers from Harvard Medical School, US, monitored brain activity of 25 participants as they learned a typing sequence and then took a nap.

During sleep, areas in the cortex — the brain's outermost layer that aids higher-level functions such as memory — that were active while the participants worked showed more rhythmic, repetitive patterns, indicating the task-related information was being processed, the researchers found.

The results, published in the Journal of Neuroscience, also show that an increased number of brain waves in these cortical areas was associated with improved performance after the nap.

“During sleep, cortical brain areas active during training had more rhythmic activity. Increased brain rhythms in these areas correlated with how much participants improved in the task after the nap,” the authors wrote.

Further, the study found that performance during learning was linked to increased activity during sleep in brain regions involved in executing movement — possibly representing the memory of the task.

However, performance after the nap was linked to increased activity in brain regions involved in planning movement, which the authors suggested may help enhance future task performance.

“Brain rhythms occur everywhere in the brain during sleep. But the rhythms in these regions increase after learning, presumably to stabilise and enhance memory,” said study author Dana Manoach, professor of psychology in the department of psychiatry, Harvard Medical School.