Daytime sleep improves memory consolidation

January 7, 2008

A ninety minute daytime nap helps speed up the process of long term memory consolidation, a recent study conducted by Prof. Avi Karni and Dr. Maria Korman of the Center for Brain and Behavior Research at the University of Haifa found. The research was published in the scientific journal Nature Neuroscience.

"We still don't know the exact mechanism of the memory process that occurs during sleep, but the results of this research suggest the possibility that it is possible to speed up memory consolidation, and in the future, we may be able to do it artificially," said Prof. Karni.

Long term memory is defined as a permanent memory that doesn't disappear or that disappears after many years. This part of our memory is divided into two types – memories of "what" (for example: what happened yesterday or what one remembers from an article one read yesterday) and memories of "how to" (for example: how to read Hebrew, how to drive, play basketball or play the piano).

In this new research, which was conducted by researchers at the University of Haifa in cooperation with the Sleep Laboratory at the Sheba Medical Center and researchers from the Department of Psychology at the University of Montreal, it was revealed that a daytime nap changes the course of consolidation in the brain.

Two groups of participants in the study practiced a repeated motor activity which consisted of bringing the thumb and a finger together at a specific sequence. The research examined the "how" aspect of memory in the participants' ability to perform the task quickly and in the correct sequence. One of the groups was allowed to nap for an hour and a half after learning the task while the other group stayed awake.

The group that slept in the afternoon showed a distinct improvement in their task performance by that evening, as opposed to the group that stayed awake, which did not exhibit any improvement. Following an entire night's sleep, both groups exhibited the same skill level. "This part of the research showed that a daytime nap speeds up performance improvement in the brain. After a night's sleep the two groups were at the same level, but the group that slept in the afternoon improved much faster than the group that stayed awake," stressed Prof. Karni.

A second experiment showed that another aspect of memory consolidation is accelerated by sleep. It was previously shown that during the 6-8 hours after completing an effective practice session, the neural process of "how" memory consolidation is susceptible to interference, such that if, for example, one learns or performs a second, different task, one's brain will not be able to successfully remember the first trained task.

A third group of participants in the University of Haifa study learned a different thumb-to-finger movement sequence two hours after practicing the first task. As the second task was introduced at the beginning of the 6-8 hour period during which the brain consolidates memories, the second task disturbed the memory consolidation process and this group did not show any improvement in their ability to perform the task, neither in the evening of that day nor on the following morning.

However, when a fourth group of participants was allowed a 90 minute nap between learning the first set of movements and the second, they did not show much improvement in the evening, but on the following morning these participants showed a marked improvement of their performance, as if there had been no interference at all.

"This part of the study demonstrated, for the first time, that daytime sleep can shorten the time "how to" memory becomes immune to interference and forgetting. Instead of 6-8 hours, the brain consolidated the memory during the 90 minute nap," explains Prof. Karni who added that while this study demonstrates that the process of memory consolidation is accelerated during daytime sleep, it is still not clear which mechanisms sleep accelerates in the process.

The elucidation of these mechanisms, say the researchers, could enable the development of methods to accelerate memory consolidation in adults and to create stable memories in a short time. Until then, if you need to memorize something quickly or if your schedule is filled with different activities which require learning "how" to do things, it is worth finding the time for an afternoon nap.

Source: University of Haifa

Explore further: New study finds 'baby brain' is real, but the cause remains mysterious

Related Stories

New study finds 'baby brain' is real, but the cause remains mysterious

January 15, 2018
So-called "baby brain" refers to increased forgetfulness, inattention, and mental "fogginess" reported by four out of five pregnant women. These changes in brain function during pregnancy have long been recognised in midwifery ...

Sleep-deprived brains may be asleep and awake at the same time

January 4, 2018
For something that can occupy such a significant chunk of time, sleep still remains a mysterious part of our lives. Although it is known to play a role in mental and physical health, such as metabolism and memory, there is ...

Why getting enough sleep should be on your list of New Year's resolutions

December 27, 2017
If you need an alarm to get up in the morning, you're probably not getting enough sleep.

Study shows how memories ripple through the brain

October 30, 2017
Using an innovative "NeuroGrid" technology, scientists showed that sleep boosts communication between two brain regions whose connection is critical for the formation of memories. The work, published in Science, was partially ...

New study reveals sleep deprivation disrupts brain-cell communication

November 6, 2017
Ever sleep poorly and then walk out of the house without your keys? Or space out on the highway and nearly hit a stalled car?

Why we still don't understand sleep, and why it matters

October 23, 2017
One of my first jobs was to keep a lookout for lions. There are some occupations that are not suitable for someone with untreated narcolepsy and this is probably one of them. I was 22, a recent zoology graduate studying meerkats ...

Recommended for you

Researchers illustrate how muscle growth inhibitor is activated, could aid in treating ALS

January 19, 2018
Researchers at the University of Cincinnati (UC) College of Medicine are part of an international team that has identified how the inactive or latent form of GDF8, a signaling protein also known as myostatin responsible for ...

Bioengineered soft microfibers improve T-cell production

January 18, 2018
T cells play a key role in the body's immune response against pathogens. As a new class of therapeutic approaches, T cells are being harnessed to fight cancer, promising more precise, longer-lasting mitigation than traditional, ...

Weight flux alters molecular profile, study finds

January 17, 2018
The human body undergoes dramatic changes during even short periods of weight gain and loss, according to a study led by researchers at the Stanford University School of Medicine.

Secrets of longevity protein revealed in new study

January 17, 2018
Named after the Greek goddess who spun the thread of life, Klotho proteins play an important role in the regulation of longevity and metabolism. In a recent Yale-led study, researchers revealed the three-dimensional structure ...

The HLF gene protects blood stem cells by maintaining them in a resting state

January 17, 2018
The HLF gene is necessary for maintaining blood stem cells in a resting state, which is crucial for ensuring normal blood production. This has been shown by a new research study from Lund University in Sweden published in ...

Magnetically applied MicroRNAs could one day help relieve constipation

January 17, 2018
Constipation is an underestimated and debilitating medical issue related to the opioid epidemic. As a growing concern, researchers look to new tools to help patients with this side effect of opioid use and aging.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

ShadowRam
not rated yet Jan 07, 2008
Just another perfect example of how companies should allow their employee's to nap when they need to, to improve productivity.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.