Association for Psychological Science, January 2011 — As humans, we spend about a third of our lives asleep. So there must be a point to it, right? Scientists have found that sleep helps consolidate memories, fixing them in the brain so we can retrieve them later. Now, new research is showing that sleep also seems to reorganize memories, picking out the emotional details and reconfiguring the memories to help you produce new and creative ideas, according to the authors of an article in Current Directions in Psychological Science.

“Sleep is making memories stronger,” says Jessica D. Payne of the University of Notre Dame, who co-wrote the review with Elizabeth A. Kensinger of Boston College. “It also seems to be doing something which I think is so much more interesting, and that is reorganizing and restructuring memories.”

Payne and Kensinger study what happens to memories during sleep, and they have found that a person tends to hang on to the most emotional part of a memory. For example, if someone is shown a scene with an emotional object, such as a wrecked car, in the foreground, they’re more likely to remember the emotional object than, say, the palm trees in the background — particularly if they’re tested after a night of sleep. They have also measured brain activity during sleep and found that regions of the brain involved with emotion and memory consolidation are active.

“In our fast-paced society, one of the first things to go is our sleep,” Payne says. “I think that’s based on a profound misunderstanding that the sleeping brain isn’t doing anything.” The brain is busy. It’s not just consolidating memories, it’s organizing them and picking out the most salient information. She thinks this is what makes it possible for people to come up with creative, new ideas.

Payne has taken the research to heart. “I give myself an eight-hour sleep opportunity every night. I never used to do that — until I started seeing my data,” she says. People who say they’ll sleep when they’re dead are sacrificing their ability to have good thoughts now, she says. “We can get away with less sleep, but it has a profound effect on our cognitive abilities.”

Brain activity awake and asleep

University of York, Harvard University, January 2011 — It is one thing to learn a new piece of information, such as a new phone number or a new word, but quite another to get your brain to file it away so it is available when you need it.

A new study published in the Journal of Neuroscience by researchers at the University of York and Harvard Medical School suggests that sleep may help to do both.

The scientists found that sleep helps people to remember a newly learned word and incorporate new vocabulary into their “mental lexicon.”

During the study, which was funded by the Economic and Social Research Council, researchers taught volunteers new words in the evening, followed by an immediate test. The volunteers slept overnight in the laboratory while their brain activity was recorded using an electroencephalogram, or EEG. A test the following morning revealed that they could remember more words than they did immediately after learning them, and they could recognise them faster demonstrating that sleep had strengthened the new memories.

This did not occur in a control group of volunteers who were trained in the morning and re-tested in the evening, with no sleep in between. An examination of the sleep volunteers’ brainwaves showed that deep sleep (slow-wave sleep) rather than rapid eye movement (REM) sleep or light sleep helped in strengthening the new memories.

When the researchers examined whether the new words had been integrated with existing knowledge in the mental lexicon, they discovered the involvement of a different type of activity in the sleeping brain. Sleep spindles are brief but intense bursts of brain activity that reflect information transfer between different memory stores in the brain — the hippocampus deep in the brain and the neocortex, the surface of the brain.

Memories in the hippocampus are stored separately from other memories, while memories in the neocortex are connected to other knowledge. Volunteers who experienced more sleep spindles overnight were more successful in connecting the new words to the rest of the words in their mental lexicon, suggesting that the new words were communicated from the hippocampus to the neocortex during sleep.

Co-author of the paper, Professor Gareth Gaskell, of the University of York’s Department of Psychology, said: “We suspected from previous work that sleep had a role to play in the reorganisation of new memories, but this is the first time we’ve really been able to observe it in action, and understand the importance of spindle activity in the process.”

These results highlight the importance of sleep and the underlying brain processes for expanding vocabulary. But the same principles are likely to apply to other types of learning.

Lead author, Dr Jakke Tamminen, said: “New memories are only really useful if you can connect them to information you already know. Imagine a game of chess, and being told that the rule governing the movement of a specific piece has just changed. That new information is only useful to you once you can modify your game strategy, the knowledge of how the other pieces move, and how to respond to your opponent’s moves. Our study identifies the brain activity during sleep that organises new memories and makes those vital connections with existing knowledge.”

Journal Reference:  —  J. Tamminen, J. D. Payne, R. Stickgold, E. J. Wamsley, M. G. Gaskell. Sleep Spindle Activity is Associated with the Integration of New Memories and Existing Knowledge. Journal of Neuroscience, 2010; 30 (43): 14356 DOI: 10.1523/JNEUROSCI.3028-10.2010

Diagram of Right Side of Brain That Controls Dreams

Biological Psychiatry, Dec/Jan 2011  —  We commonly think of sleep as a healing process that melts away the stresses of the day, preparing us to deal with new challenges. Research has also shown that sleep plays a crucial role in the development of memories.

An important component of anxiety disorders, including posttraumatic stress disorder (PTSD), is the formulation of memories associated with fear.

Therefore, researchers decided to evaluate whether sleep deprivation after exposure to an aversive event might eliminate the associated fear, due to the lack of memory consolidation that would typically occur during sleep.

They evaluated healthy volunteers who were shown video clips of both safe driving and unexpected motor vehicle accidents. Half of the volunteers were then deprived of sleep while the other half received a normal night’s sleep.

Later testing sessions revealed that sleep deprivation eliminated the fear-associated memories through both fear recognition and physiological fear reactions, suggesting a possible therapy for individuals with PTSD or other anxiety disorders.

Dr. Kenichi Kuriyama, corresponding author, explained: “Sleep deprivation after exposure to a traumatic event, whether intentional or not, may help prevent PTSD. Our findings may help to clarify the functional role of acute insomnia and to develop a prophylactic strategy of sleep restriction for prevention of PTSD.”

“It would be nice if the benefits of sleep deprivation upon fear learning could be produced more easily for survivors of extreme stress,” noted John Krystal, M.D., Editor of Biological Psychiatry and Professor and Chair of Psychiatry at Yale University. “New insights into the neurobiology of sleep dependent learning may make it possible for these people to take a medication that disrupts this process while leaving restorative elements of sleep intact.”

Further research is necessary, but these findings indicate that sleep deprivation is a promising avenue for the possible treatment and prevention of PTSD.

Journal Reference:

1. Kenichi Kuriyama, Takahiro Soshi, and Yoshiharu Kim. Sleep Deprivation Facilitates Extinction of Implicit Fear Generalization and Physiological Response to Fear. Biological Psychiatry, Volume 68, Number 11

The algorithm can read which of three short films human volunteers are thinking about

MRI machine A researcher prepares to go into an MRI machine (NOT an fMRI machine) at the Wellcome Trust Center for Neuroimaging. University College London

Wellcome Trust, 2010/201, by Jeremy Hsu —  Computer programs have been able to predict which of three short films a person is thinking about, just by looking at their brain activity. The research, conducted by scientists at the Wellcome Trust Centre for Neuroimaging at UCL (University College London), provides further insight into how our memories are recorded.

Professor Eleanor Maguire led this Wellcome Trust-funded study, an extension of work published last year which showed how spatial memories — in that case, where a volunteer was standing in a virtual reality room — are recorded in regular patterns of activity in the hippocampus, the area of the brain responsible for learning and memory.

“In our previous experiment, we were looking at basic memories, at someone’s location in an environment,” says Professor Maguire. “What is more interesting is to look at ‘episodic’ memories — the complex, everyday memories that include much more information on where we are, what we are doing and how we feel.”

To explore how such memories are recorded, the researchers showed ten volunteers three short films and asked them to memorise what they saw. The films were very simple, sharing a number of similar features — all included a woman carrying out an everyday task in a typical urban street, and each film was the same length, seven seconds long. For example, one film showed a woman drinking coffee from a paper cup in the street before discarding the cup in a litter bin; another film showed a (different) woman posting a letter.

The volunteers were then asked to recall each of the films in turn whilst inside an fMRI scanner, which records brain activity by measuring changes in blood flow within the brain.

A computer algorithm then studied the patterns and had to identify which film the volunteer was recalling purely by looking at the pattern of their brain activity. The results are published in the journal Current Biology.

“The algorithm was able to predict correctly which of the three films the volunteer was recalling significantly above what would be expected by chance,” explains Martin Chadwick, lead author of the study. “This suggests that our memories are recorded in a regular pattern.”

Although a whole network of brain areas support memory, the researchers focused their study on the medial temporal lobe, an area deep within the brain believed to be most heavily involved in episodic memory. It includes the hippocampus — an area which Professor Maguire and colleagues have studied extensively in the past.

They found that the key areas involved in recording the memories were the hippocampus and its immediate neighbours. However, the computer algorithm performed best when analysing activity in the hippocampus itself, suggesting that this is the most important region for recording episodic memories. In particular, three areas of the hippocampus — the rear right and the front left and front right areas — seemed to be involved consistently across all participants. The rear right area had been implicated in the earlier study, further enforcing the idea that this is where spatial information is recorded. However, it is still not clear what role the front two regions play.

“Now that we are developing a clearer picture of how our memories are stored, we hope to examine how they are affected by time, the ageing process and by brain injury,” says Professor Maguire.

Journal Reference:

1. Martin J. Chadwick, Demis Hassabis, Nikolaus Weiskopf, and Eleanor A. Maguire. Decoding Individual Episodic Memory Traces in the Human Hippocampus. Current Biology, 2010; DOI: 10.1016/j.cub.2010.01.053

A bumblebee gathers pollen from a sunflower in Sumartin on Croatia‘s Adriatic Island of Brac July 18, 2009. REUTERS/Nikola Solic

By Maggie Fox, Health
and Science Editor, Posted 2011/01/05,, WASHINGTON, Jan. 5, 2011 (Reuters) — Four previously abundant species of bumblebee are close to disappearing in the United States, researchers reported on Monday in a study confirming that the agriculturally important bees are being affected worldwide.

In recent years, experts have documented a disappearance of bees in what is widely called colony collapse disorder, blamed on many factors including parasites, fungi, stress, pesticides and viruses. But most studies have focused on honeybees.

Bumblebees are also important pollinators, Cameron said, but are far less studied. Bumblebees pollinate tomatoes, blueberries and cranberries, she noted.

“The 50 species (of bumblebees) in the United States are traditionally associated with prairies and with high alpine vegetations,” she added.

“Just as important — they land on a flower and they have this behavior called buzz pollination that enables them to cause pollen to fly off the flower.”


This is the way to pollinate tomatoes, Cameron said — although smaller bees can accomplish the same effect if enough cluster on a single flower.

Several reports have documented the disappearance of bumblebees in Europe and Asia, but no one had done a large national study in the Americas.

Cameron’s team did a three-year study of 382 sites in 40 states and also looked at more than 73,000 museum records.

“We show that the relative abundance of four species have declined by up to 96 percent and that their surveyed geographic ranges have contracted by 23 percent to 87 percent,” they wrote.

While no crops are in immediate danger, the results show that experts need to pay attention, Cameron said. Pollinators such as bees and bats often have specific tongue lengths and pollination behaviors that have evolved along with the species of plants they pollinate.

Bumblebees can fly in colder weather than other species, and are key to pollinating native species in the tundra and at high elevations, Cameron said.

Genetic tests show that the four affected bumblebee species have a risky lack of genetic diversity and other tests implicate a parasite called Nosema bombi, Cameron said.

“This is a wake-up call that bumblebee species are declining not only in Europe, not only in Asia, but also in North America,” she said.

(Editing by Vicki Allen)