Trading in that final hour of cramming for another hour of sleep the night before a big test may actually be beneficial to sustaining information and being receptive the next day, recent evidence from UC Berkeley researchers suggests.

In a study published March 8 in the journal Current Biology, UC Berkeley researchers found that brain waves, known as "sleep spindles," move information from the brain's hippocampus - which has limited storage capacity - to another part of the brain, allowing it to absorb new information. However, these sleep spindles only come to life during stage 2 of non-Rapid Eye Movement sleep, which occurs frequently during the second half of a sleep cycle.

Therefore, sleeping six hours or less can be detrimental to your memory because not enough sleep spindles are generated in this short time span.

"If you deprive or restrict someone of sleep, stage 2 is the first to go," said Bryce Mander, lead author of the study and a postdoctoral fellow in psychology at UC Berkeley. "Sleep spindles are important for learning, and they show you how sleep facilitates something you learn."

Matthew Walker, associate professor of psychology and neuroscience at UC Berkeley, was a senior author of the study, which was funded entirely by federal grants from the National Institute of Health, along with Mander.

The sleep patterns of 44 adults from UC Berkeley were recorded for five days before the tests formally began. After this five-day period, participants were separated into a nap group and a control group that was not allowed to take naps. Both groups had to refrain from caffeine, drug and alcohol use before they came in to participate in the test studies, which consisted of two rounds of face and name recognition before and after the wake period.

Though there has been evidence from previous studies that sleep loss is associated with impaired ability to learn, these particular study results indicated that the test group that had napped performed better at name recognition than the group that had stayed awake.

"The lack of sleep is endemic to undergraduate college students," said Jared Saletin, a co-researcher of the study and a UC Berkeley psychology graduate student in the Sleep and Neuroimaging Laboratory. "Though the study is only a nap and not a replication of what college students go through every day, it does hint that having sleep makes you better prepared to learn."

In an effort to improve overall performance and stress management, the Tang Center provides education on the importance of sleep in its "Be Well to Do Well" campaign, according to Cathy Kodama, the health promotion director for University Health Services.

Sangeetha Santhanam, another co-researcher of the study and a UC Berkeley alumna, said the study motivated her to get more sleep and encourage others to do the same.

"Before this study, I had an absolute disregard for sleep," Santhanam said. "Now I know that sleep hygiene determines how well you sleep and what your body requires to consolidate memories."

Saletin also said that sleep spindles affect elementary school children who attend school at earlier times.

"Children are waking up too early for school, cutting off a certain part of their sleep in the morning," Saletin said. "Later school start times mean a full night of sleep that may impact learning. A critical time of learning is when kids are in school, but school start times are getting earlier and earlier."