Findings reveal brain mechanisms at work during sleep

One in five American adults show signs of chronic sleep deprivation, making the condition a widespread public health problem. Sleeplessness is related to health issues such as obesity, cardiovascular problems, and memory problems.

Today’s findings show that:

• Sleepiness disrupts the coordinated activity of an important network of brain regions; the impaired function of this network is also implicated in Alzheimer’s disease (Andrew Ward, abstract 909.05).
• Sleeplessness plays havoc with communication between the hippocampus, which is vital for memory, and the brain’s “default mode network;” the changes may weaken event recollection (Hengyi Rao, PhD, abstract 626.08).
• In a mouse model, fearful memories can be intentionally weakened during sleep, indicating new possibilities for treatment of post-traumatic stress disorder (Asya Rolls, abstract 807.06).
• Loss of less than half a night’s sleep can impair memory and alter the normal behavior of brain cells (Ted Abel, PhD, abstract 807.13).

Other recent findings discussed show:
• How sleep enables the remodeling of memories — including the weakening of irrelevant memories — and the coherent integration of old and new information (Gina Poe, PhD).
• The common logic behind seemingly contradictory theories of how sleep remodels synapses, aiding cognition and memory consolidation (Giulio Tononi, MD, PhD).

Study shows old adage ‘sleep on it’ is true – but only if it’s a really difficult problem

A new study from Lancaster University has found that sleeping on a problem really can help people to find a solution.

The study, published online this week in the journal Memory & Cognition, tested whether sleep or time spent awake worked best in helping people find the solutions to a range of problem solving tasks.

The authors of the study - Ut Na Sio, Padraic Monaghan and Tom Ormerod all from the Centre for Research in Human Development and Learning at Lancaster’s Department of Psychology - concluded that sleep facilitates problem solving but this has its primary effect for harder problems.

Professor Padraic Monaghan said: “We’ve known for years that sleep has a profound effect on our ability to be creative and find new solutions to problems. Our study shows that this sleep effect is greatest when the problems facing us are difficult. Sleep appears to help us solve problems by accessing information that is remote to the initial problem, that may not be initially brought to mind. Sleep has been proposed to ‘spread activation’ to the solution that is initially distant from our first attempts at the problem. The advice stemming from this and related research is to leave a problem aside if you’re stuck, and get some sleep if it’s a really difficult problem.”

What Drives Your Daily Biological Clock?

Researchers working with fruit flies say they have discovered one way that the body’s biological clock controls brain-cell activity that influences daily rhythms.

They believe their findings might improve understanding about sleep-wake cycles and lead to new treatments for sleep disorders and jet lag.

"The findings answer a significant question: how biological clocks drive the activity of clock neurons, which, in turn, regulate behavioral rhythms," study senior author Justin Blau, associate professor in New York University’s department of biology, said in a university news release.

Previous research with fruit flies’ “clock genes” led to the discovery of similar genes in humans, according to the news release.

It was known that biological clocks control neuronal activity, but it wasn’t known how information from biological clocks drives rhythms in the electrical activity of pacemaker neurons that control daily rhythms.

The NYU team looked at pacemaker neurons in the central brain of fruit flies that set the timing of the daily transitions between sleep and wake. They isolated these neurons and identified sets of genes with different levels of activity at dawn and dusk.

Follow-up experiments found that the activity of a gene called Ir was much higher at dusk than at dawn and that it was more active in the pacemaker neurons than in the rest of the brain. The researchers also found that increasing or decreasing levels of Ir affected behavioral rhythms and changed the timing and strength of variations in the core clock.

"We were looking for an output of the biological clock that would link the core clock to neuronal activity," Blau said. "Ir seems to do this, but it also, remarkably, feeds back to regulate the core clock itself. Feedback loops seem to be deeply engrained into the biological clock and presumably help these clocks work so well."

The study was published in the October issue of the Journal of Biological Rhythms. Researchers have noted that results from animal studies do not necessarily translate to humans.

Sleep loss links to illness studied

Insomniacs know the pattern all too well. You toss and turn at night, kept awake by the rave down the street, stress from work, the snores of a significant other.

After a stretch of restless evenings, you wake up with a sore throat or a fever. You’re no longer just tired - you’re also sick.

Physicians know this pattern, too. Constant lack of sleep has long been linked with a laundry list of unpleasant conditions: cardiovascular disease, diabetes, weight gain, infectious illnesses and even death.

While it’s common knowledge that a full night of rest helps ward off ailments, what largely remains a mystery is exactly how sleep loss triggers the biological mechanisms that in turn bring about illness - like the common cold.

A 2009 study of 153 men and women, for example, showed that those who slept fewer than seven hours on average per night were about three times more likely to develop a cold than those with at least eight hours of sleep daily.

Even a small difference in sleep quality made a big difference in health, the Carnegie Mellon University study showed. Participants who actually slept less than 92 percent of the time between the time they laid down to sleep and when they woke up were 5.5 times more likely to develop a cold than those who stayed asleep 98 percent or more of the time, according to the researchers.

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Rethinking Sleep

SOMETIME in the dark stretch of the night it happens. Perhaps it’s the chime of an incoming text message. Or your iPhone screen lights up to alert you to a new e-mail. Or you find yourself staring at the ceiling, replaying the day in your head. Next thing you know, you’re out of bed and engaged with the world, once again ignoring the often quoted fact that eight straight hours of sleep is essential.

Sound familiar? You’re not alone. Thanks in part to technology and its constant pinging and chiming, roughly 41 million people in the United States — nearly a third of all working adults — get six hours or fewer of sleep a night, according to a recent report from the Centers for Disease Control and Prevention. And sleep deprivation is an affliction that crosses economic lines. About 42 percent of workers in the mining industry are sleep-deprived, while about 27 percent of financial or insurance industry workers share the same complaint.

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Robots paint hotel guests’ sleep patterns

Global hotel chain Ibis is transforming the nightly tosses and turns of its guests into works of modern art, painted by robots.

"Our masterpiece is to make your sleep a true work of art," the promotional video gushes, after putting a far more interesting point to viewers: "What does sleep look like?" To find out, the budget chain is installing thin grids covered in 80 heat, pressure and sound sensors on mattresses in select guestrooms, kicking off on 13 October in Paris. Data gathered by the sensors will be fed wirelessly throughout the night to the studio, where it is then fed through an algorithm that converts information on a guest’s movement, sound and temperature into colour and movement.

This video shows the robot, much like an assembly line arm, reacting in sequence, tracing acrylic paints onto a black canvas in a visual and physical interpretation of sleep cycles and patterns.

Only 40 participants can take part — anyone who wants to try it out can enter a competition on the Ibis Facebook page. When the project is wrapped up in Novemeber there will be an online gallery of the artworks and guests will get an original to take home.

NYU Biologists Uncover Dynamic Between Biological Clock and Neuronal Activity

Biologists at New York University have uncovered one way that biological clocks control neuronal activity—a discovery that sheds new light on sleep-wake cycles and offers potential new directions for research into therapies to address sleep disorders and jetlag.

“The findings answer a significant question—how biological clocks drive the activity of clock neurons, which, in turn, regulate behavioral rhythms,” explained Justin Blau, an associate professor in NYU’s Department of Biology and the study’s senior author.

Their findings appear in the Journal of Biological Rhythms

Sleep Oscillations in the Thalamocortical System Induce Long-Term Neuronal Plasticity

Long-term plasticity contributes to memory formation and sleep plays a critical role in memory consolidation. However, it is unclear whether sleep slow oscillation by itself induces long-term plasticity that contributes to memory retention. Using in vivo prethalamic electrical stimulation at 1 Hz, which itself does not induce immediate potentiation of evoked responses, we investigated how the cortical evoked response was modulated by different states of vigilance. We found that somatosensory evoked potentials during wake were enhanced after a slow-wave sleep episode (with or without stimulation during sleep) as compared to a previous wake episode. In vitro, we determined that this enhancement has a postsynaptic mechanism that is calcium dependent, requires hyperpolarization periods (slow waves), and requires a coactivation of both AMPA and NMDA receptors. Our results suggest that long-term potentiation occurs during slow-wave sleep, supporting its contribution to memory.