Bad sleep habits linked to higher self-control risks

July 2, 2015
Science Daily/Clemson University
Poor sleep habits can have a negative effect on self-control, which presents risks to individuals' personal and professional lives, according to researchers. Psychologists concluded a sleep-deprived individual is at increased risk for succumbing to impulsive desires, inattentiveness and questionable decision-making.

n a study titled "Interactions between Sleep Habits and Self-Control," Clemson psychologists concluded a sleep-deprived individual is at increased risk for succumbing to impulsive desires, inattentiveness and questionable decision-making.

"Self-control is part of daily decision-making. When presented with conflicting desires and opportunities, self-control allows one to maintain control," said June Pilcher, Clemson Alumni Distinguished Professor of psychology, one of four authors of the study. "Our study explored how sleep habits and self-control are interwoven and how sleep habits and self-control may work together to affect a person's daily functioning."

Other Clemson researchers included Drew Morris, a human factors psychology Ph.D. candidate; Janet Donnelly, a Ph.D. candidate in industrial/organizational psychology; and Hayley B. Feigl, who has a Bachelor of Science in psychology.

Previous research has shown individuals working in today's 24-hour-a-day global economy often times sleep less or at irregular times, resulting in poor sleep and chronic sleep loss, which affects decision-making.

"Exercising self-control allows one to make better choices when presented with conflicting desires and opportunities. That has far-reaching implications to a person's career and personal life," Pilcher said.

Poor sleep habits, which include inconsistent sleep times and not enough hours of sleep, can also lead to health problems, including weight gain, hypertension and illness, according to prior research. Studies have also found that sleep deprivation decreases self-control but increases hostility in people, which can create problems in the workplace and at home," Pilcher said.

Better sleep habits can contribute to a more stable level of daily energy reserves, research has indicated. Availability of energy can refuel a person's ability to make more difficult choices rather than opting for the easier choice or the easier task.

"Many aspects of our daily lives can be affected by better-managed sleep and self-control capacity," Pilcher said. "Improved health and worker performance are two potential benefits, but societal issues such as addictions, excessive gambling and over spending could also be more controllable when sleep deficiencies aren't interfering with one's decision making."
http://www.sciencedaily.com/releases/2015/07/150702104128.htm

Can you actually hear 'inaudible' sound?

July 10, 2015
Science Daily/Physikalisch-Technische Bundesanstalt (PTB)
Limits of human hearing (infrasound and ultrasound) examined
Are wind farms harmful to humans? This controversial topic makes emotions run high. To give the debate more objectivity, an international team of experts dealt with the fundamentals of hearing in the lower limit range of the audible frequency range (i.e., infrasound), but also in the upper limit range (i.e., ultrasound).
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If there is a plan to erect a wind turbine in front of someone's property, many an eager supporter of the "energy transition" quickly turns into a wind energy opponent. Fear soon starts spreading: the infrasound generated by the rotor blades and by the wind flow might make someone ill. Many people living in the vicinity of such wind farms do indeed experience sleep disturbances, a decline in performance, and other negative effects. Infrasound designates very low sounds, below the limit of hearing, which is around 16 hertz. The wind energy sector and the authorities often try to appease the situation, declaring that the sounds generated are inaudible and much too weak to be the source of health problems.

Christian Koch knows for sure, "Neither scaremongering nor refuting everything is of any help in this situation. Instead, we must try to find out more about how sounds in the limit range of hearing are perceived." This expert in acoustics from PTB is the manager of the international project in which metrology experts from several metrology institutes and scientists from the Max Planck Institute for Human Development in Berlin investigated the fundamentals of the hearing of "inaudible" sounds for 3 years. Very low sounds (i.e. infrasound, below approx. 16 hertz) or very high sounds (i.e. ultrasound, above approx. 16,000 hertz) occur in numerous situations of daily life: infrasound is not only produced by wind turbines, but also sometimes when a truck thunders past a house, or when a home owner installs a power generator in his basement. Ultrasound can, for example, originate from commercial ultrasonic cleaning baths that are sometimes used, e.g., to thoroughly clean a pair of glasses. It can also be generated by a device used as a deterrent against martens (to keep them from gnawing on the wiring of cars). A particular variant of such devices has been developed to keep young people away from certain places -- an internationally controversial topic from an ethical viewpoint. These devices, which produce very high-pitched sounds that can only be heard by children and young people, are sometimes used by adults who want to enjoy some peace and quiet. "In all these areas, we have to deal with considerable levels of loudness in some cases," Christian Koch adds.

An audible loud sound may damage hearing -- as well as getting on your nerves. But what exactly is an "audible" sound? And what does a human being really hear? In order to find out more, an infrasonic source which is able to generate sounds that are completely free from harmonics (which is not as trivial as it may sound!) was constructed within the scope of this project. Test persons were asked about their subjective hearing experience, and these (also quantitative) statements were then compared by means of imaging procedures, namely by magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI). The results have shown that humans hear lower sounds -- namely from 8 hertz on -- which, after all, is a whole octave than had previously been assumed: an excitation of the primary auditory cortex could be detected down to this frequency. All persons concerned explicitly stated that they had heard something -- whereby this perception had not always been tonal. In addition, the observations showed a reaction in certain parts of the brain which play a role in emotions. "This means that a human being has a rather diffuse perception, saying that something is there and that this might involve danger," Christian Koch says. "But we're actually at the very beginning of our investigations. Further research is urgently needed." An application for a follow-up project has already been filed. In this project, the investigations will be focused on the question why some persons feel disturbed by "inaudible" sound, whereas others are not even bothered: many a home owner is left cold by having a wind turbine next to their homes. And we need to take another effect into account: namely, that some people become really ill because they imagine risks which, in reality, might not even exist. This is the reason why it makes sense to involve psychologists as well.

But the researchers see a great need for further research also in the other extreme -- the ultrasound. Although the measuring instruments used are among the most precise in the world (PTB is the world leader, especially for MEG), the researchers were not able to measure whether humans can hear above the previously assumed upper threshold of hearing, and if they can, what they then perceive. Since, however, what applies to other ranges, also applies to high-pitched sounds -- namely that a very loud sound may damage the hearing -- here too, there is a need for further research.

The results of the international research project might lead to the introduction of uniform -- and binding -- protection provisions for these limit ranges of hearing within Europe, since there have been none to date.
http://www.sciencedaily.com/releases/2015/07/150710123506.htm

New compounds may treat depression rapidly with few side effects

July 13, 2015
Science Daily/University of Maryland School of Medicine
New approach could revolutionize treatment
A new study has identified promising compounds that could successfully treat depression in less than 24 hours with few side effects. The compounds could offer significant advantages over current antidepressant medications.

The research, led by Scott Thompson, PhD, Professor and Chair of the Department of Physiology at the University of Maryland School of Medicine (UM SOM), was published this month in the journal Neuropsychopharmacology.

"Our results open up a whole new class of potential antidepressant medications," said Dr. Thompson. "We have evidence that these compounds can relieve the devastating symptoms of depression in less than one day, and can do so in a way that limits some of the key disadvantages of current approaches."

Currently, most people with depression take medications that increase levels of the neurochemical serotonin in the brain. The most common of these drugs, such as Prozac and Lexapro, are selective serotonin reuptake inhibitors, or SSRIs. Unfortunately, SSRIs are effective in only a third of patients with depression. In addition, even when these drugs work, they typically take between three and eight weeks to relieve symptoms. As a result, patients often suffer for months before finding a medicine that makes them feel better. This is not only emotionally excruciating; in the case of patients who are suicidal, it can be deadly. Better treatments for depression are clearly needed.

Dr. Thompson and his team focused on another neurotransmitter besides serotonin, an inhibitory compound called GABA. Brain activity is determined by a balance of opposing excitatory and inhibitory communication between brain cells. Dr. Thompson and his team argue that in depression, excitatory messages in some brain regions are not strong enough. Because there is no safe way to directly strengthen excitatory communication, they examined a class of compounds that reduce the inhibitory messages sent via GABA. They predicted that these compounds would restore excitatory strength. These compounds, called GABA-NAMs, minimize unwanted side effects because they are precise: they work only in the parts of the brain that are essential for mood.

The researchers tested the compounds in rats that were subjected to chronic mild stress that caused the animals to act in ways that resemble human depression. Giving stressed rats GABA-NAMs successfully reversed experimental signs of a key symptom of depression, anhedonia, or the inability to feel pleasure. Remarkably, the beneficial effects of the compounds appeared within 24 hours -- much faster than the multiple weeks needed for SSRIs to produce the same effects.

"These compounds produced the most dramatic effects in animal studies that we could have hoped for," Dr. Thompson said. "It will now be tremendously exciting to find out whether they produce similar effects in depressed patients. If these compounds can quickly provide relief of the symptoms of human depression, such as suicidal thinking, it could revolutionize the way patients are treated."

In tests on the rats' brains, the researchers found that the compounds rapidly increased the strength of excitatory communication in regions that were weakened by stress and are thought to be weakened in human depression. No effects of the compound were detected in unstressed animals, raising hopes that they will not produce side effects in human patients.

"This work underscores the importance of basic research to our clinical future," said Dean E. Albert Reece, MD, PhD, MBA, who is also the vice president for Medical Affairs, University of Maryland, and the John Z. and Akiko K. Bowers Distinguished Professor and Dean of the School of Medicine. "Dr. Thompson's work lays the crucial groundwork to transform the treatment of depression and reduce the tragic loss of lives to suicide."
http://www.sciencedaily.com/releases/2015/07/150713131349.htm

Losing half a night of sleep makes memories less accessible in stressful situations

July 13, 2015
Science Daily/Uppsala University
It is known that sleep facilitates the formation of long-term memory in humans. Researchers now show that sleep does not only help form long-term memory but also ensures access to it during times of cognitive stress.

It is well known that during sleep newly learned information is transferred from short-term to long-term memory stores in humans. In the study that is now being published in the scientific journal SLEEP, sleep researchers Jonathan Cedernaes and Christian Benedict, sought to investigate the role of nocturnal sleep duration for this memory transfer, and how long-term memories formed by sleep remain accessible after acute cognitive stress.

Following a learning session in the evening during which 15 participants learned 15 card pair locations on a computer screen, in one experimental session subjects slept for half a night (4-hr) and in the other for a full night (8-hr). The next morning subjects were asked to recall as many card pair locations as possible. What the researchers found was that half a night of sleep (4-hr) was as powerful as a full night of sleep (8-hr) to form long-term memories for the learned card pair locations.

However, the study also revealed that stress had an impact on the participants' ability to recall these memories. The men were acutely stressed for 30 minutes in the morning after a half or full night of sleep (for example by having to recall a newly learnt list of words while exposed to noise). Following short sleep this stress exposure reduced their ability to recall these card pair locations by around 10 percent.

In contrast, no such stress-induced impairment was seen when the same men were allowed to sleep for a full night.

"On the basis of our study findings, we have two important take home messages: First, even though losing half a night of sleep may not impair memory functions under baseline conditions, the addition of acute cognitive stress may be enough to lead to significant impairments, which can possibly be detrimental in real-world scenarios. Second, interventions such as delaying school start times and greater use of flexible work schedules, that increase available snooze time for those who are on habitual short sleep, may improve their academic and occupational performance by ensuring optimal access to memories under stressful conditions," says Jonathan Cedernaes, researcher at the Department of Neuroscience, Uppsala University.

"An important next step will be to investigate how chronic sleep loss and or more chronic stress may interact to impair the ability to retrieve memories that are consolidated during sleep," says Jonathan Cedernaes.
http://www.sciencedaily.com/releases/2015/07/150713150822.htm

The sleep-deprived brain can mistake friends for foes

July 15, 2015
Science Daily/University of California - Berkeley
If you can't tell a smile from a scowl, you're probably not getting enough sleep
A new study shows that sleep deprivation dulls our ability to accurately read facial expressions. This deficit can have serious consequences, such as not noticing that a child is sick or in pain, or that a potential mugger or violent predator is approaching.
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"Recognizing the emotional expressions of someone else changes everything about whether or not you decide to interact with them, and in return, whether they interact with you," said study senior author Matthew Walker, a professor of psychology and neuroscience at UC Berkeley. The findings were published today in the Journal of Neuroscience.

"These findings are especially worrying considering that two-thirds of people in the developed nations fail to get sufficient sleep," Walker added.

Indeed, the results do not bode well for countless sleep-starved groups, said study lead author Andrea Goldstein-Piekarski, a postdoctoral fellow at Stanford University, who started the study as a Ph.D. student at UC Berkeley.

"Consider the implications for students pulling all-nighters, emergency-room medical staff, military fighters in war zones and police officers on graveyard shifts," she said.

For the experiment, 18 healthy young adults viewed 70 facial expressions that ranged from friendly to threatening, once after a full night of sleep, and once after 24 hours of being awake. Researchers scanned participants' brains and measured their heart rates as they looked at the series of visages.

Brain scans as they carried out these tasks -- generated through functional Magnetic Resonance Imaging (fMRI) -- revealed that the sleep-deprived brains could not distinguish between threatening and friendly faces, specifically in the emotion-sensing regions of the brain's anterior insula and anterior cingulate cortex.

Additionally, the heart rates of sleep-deprived study participants did not respond normally to threatening or friendly facial expressions. Moreover, researchers found a disconnection in the neural link between the brain and heart that typically enables the body to sense distress signals.

"Sleep deprivation appears to dislocate the body from the brain," said Walker. "You can't follow your heart."

As a consequence, study participants interpreted more faces, even the friendly or neutral ones, as threatening when sleep-deprived.

"They failed our emotional Rorschach test," Walker said. "Insufficient sleep removes the rose tint to our emotional world, causing an overestimation of threat. This may explain why people who report getting too little sleep are less social and more lonely."

On a more positive note, researchers recorded the electrical brain activity of the participants during their full night of sleep, and found that their quality of Rapid Eye Movement (REM) or dream sleep correlated with their ability to accurately read facial expressions. Previous research by Walker has found that REM sleep serves to reduce stress neurochemicals and soften painful memories.

"The better the quality of dream sleep, the more accurate the brain and body was at differentiating between facial expressions," Walker said. "Dream sleep appears to reset the magnetic north of our emotional compass. This study provides yet more proof of our essential need for sleep."
http://www.sciencedaily.com/releases/2015/07/150715103516.htm

Sleep makes our memories more accessible

July 26, 2015
Science Daily/University of Exeter
Sleeping not only protects memories from being forgotten, it also makes them easier to access, according to new research. A new study tracked memories for novel, made-up words learnt either prior to a night's sleep, or an equivalent period of wakefulness. Subjects were asked to recall words immediately after exposure, and then again after the period of sleep or wakefulness.
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In two situations where subjects forgot information over the course of 12 hours of wakefulness, a night's sleep was shown to promote access to memory traces that had initially been too weak to be retrieved.

The research, published in the journal Cortex, tracked memories for novel, made-up words learnt either prior to a night's sleep, or an equivalent period of wakefulness. Subjects were asked to recall words immediately after exposure, and then again after the period of sleep or wakefulness.

The key distinction was between those word memories which participants could remember at both the immediate test and the 12-hour retest, and those not remembered at test, but eventually remembered at retest.

The researcher found that, compared to daytime wakefulness, sleep helped rescue unrecalled memories more than it prevented memory loss.

Nicolas Dumay of the University of Exeter explains: "Sleep almost doubles our chances of remembering previously unrecalled material. The post-sleep boost in memory accessibility may indicate that some memories are sharpened overnight. This supports the notion that, while asleep, we actively rehearse information flagged as important. More research is needed into the functional significance of this rehearsal and whether, for instance, it allows memories to be accessible in a wider range of contexts, hence making them more useful."

The beneficial impact of sleep on memory is well established, and the act of sleeping is known to help us remember the things that we did, or heard, the previous day. The idea that memories could also be sharpened and made more vivid and accessible overnight, however, is yet to be fully explored.

Dr Dumay believes the memory boost comes from the hippocampus, an inner structure of the temporal lobe, unzipping recently encoded episodes and replaying them to regions of the brain originally involved in their capture -- this would lead the subject to effectively re-experience the major events of the day.

Nicolas Dumay is an experimental psychologist at the University of Exeter and an honorary Staff Scientist at the Basque Centre for Cognition, Brain and Language (BCBL), in Spain.

'Sleep not just protects memories against forgetting, it also makes them more accessible' is published in the journal Cortex.
http://www.sciencedaily.com/releases/2015/07/150726200036.htm

It don't mean a thing if the brain ain't got that swing

July 27, 2015
Science Daily/University of California - Berkeley
New study paves the way for treating brain rhythm disorders
Like Duke Ellington's 1931 jazz standard, the human brain improvises while its rhythm section keeps up a steady beat. But when it comes to taking on intellectually challenging tasks, groups of neurons tune in to one another for a fraction of a second and harmonize, then go back to improvising, according to new research.
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These findings, reported in the journal Nature Neuroscience, could pave the way for more targeted treatments for people with brain disorders marked by fast, slow or chaotic brain waves, also known as neural oscillations.

Tracking the changing rhythms of the healthy human brain at work advances our understanding of such disorders as Parkinson's disease, schizophrenia and even autism, which are characterized in part by offbeat brain rhythms. In jazz lingo, for example, bands of neurons in certain mental illnesses may be malfunctioning because they're tuning in to blue notes, or playing double time or half time.

"The human brain has 86 billion or so neurons all trying to talk to each other in this incredibly messy, noisy and electrochemical soup," said study lead author Bradley Voytek. "Our results help explain the mechanism for how brain networks quickly come together and break apart as needed."

Voytek and fellow researchers at UC Berkeley's Helen Wills Neuroscience Institute measured electrical activity in the brains of cognitively healthy epilepsy patients. They found that, as the mental exercises became more demanding, theta waves at 4-8 Hertz or cycles per second synchronized within the brain's frontal lobe, enabling it to connect with other brain regions, such as the motor cortex.

"In these brief moments of synchronization, quick communication occurs as the neurons between brain regions lock into these frequencies, and this measure is critical in a variety of disorders," said Voytek, an assistant professor of cognitive science at UC San Diego who conducted the study as a postdoctoral fellow in neuroscience at UC Berkeley.

Previous experiments on animals have shown how brain waves control brain activity. This latest study is among the first to use electrocorticography -- which places electrodes directly on the exposed surface of the brain -- to measure neural oscillations as people perform cognitively challenging tasks and show how these rhythms control communication between brain regions.

There are five types of brain wave frequencies -- Gamma, Beta, Alpha, Theta and Delta -- and each are thought to play a different role. For example, Theta waves help coordinate neurons as we move around our environment, and thus are key to processing spatial information.

In people with autism, the connection between Alpha waves and neural activity has been found to weaken when they process emotional images. Meanwhile, people with Parkinson's disease show abnormally strong Beta waves in the motor cortex. This locks neurons into the wrong groove and inhibits movement. Fortunately, electrical deep brain stimulation can disrupt abnormally strong Beta waves in Parkinson's and alleviate symptoms, Voytek said.

For the study, epilepsy patients viewed shapes of increasing complexity on a computer screen and were tasked with using different fingers (index or middle) to push a button depending on the shape, color or texture of the shape. The exercise started out simply with participants hitting the button with, say, an index finger each time a square flashed on the screen. But it grew progressively more difficult as the shapes became more layered with colors and textures, and their fingers had to keep up.

As the tasks became more demanding, the oscillations kept up, coordinating more parts of the frontal lobe and synchronizing the information passing between those brain regions.

"The results revealed a delicate coordination in the brain's code," Voytek said. "Our neural orchestra may need no conductor, just brain waves sweeping through to briefly excite neurons, like millions of fans in a stadium doing 'The Wave.'"
http://www.sciencedaily.com/releases/2015/07/150727130821.htm

Study finds brain chemicals that keep wakefulness in check

July 29, 2015
Science Daily/Imperial College London
Mice that have a particular brain chemical switched off become hyperactive and sleep for just 65 per cent of their normal time, a new study shows. This discovery could help researchers to develop new drugs that promote better sleep, or control hyperactivity in people with the medical condition mania.

This discovery, published in the journal Neuron, could help researchers to develop new drugs that promote better sleep, or control hyperactivity in people with the medical condition mania.

Scientists altered the neurochemistry of mice to help investigate why we need to sleep, what controls our wakefulness, and how a balance between these two states influences brain functions like concentration and memory and our general health.

The chemicals they studied, histamine and GABA, are produced in a primitive part of the brain that is highly similar in mice and humans.

The team of scientists was led by Dr Stephen Brickley, Professor Nick Franks and Professor Bill Wisden from the Department of Life Sciences and the Centre for Neurotechnology at Imperial College London.

Professor Wisden said, "Sleep is essential for health. We have to do it every day. But nobody yet knows why."

Scientists already know the chemical histamine sends signals to the brain to make it awake, which is why antihistamines are associated with drowsiness. The new research suggests that the chemical GABA acts against histamine, like a chemical 'brake' preventing wakefulness being too intense.

The researchers found that GABA and histamine are made in the same brain cells, called histamine neurons, which led the scientists to question its function. They altered the levels of the GABA produced by the mice's brains and measured what changes this had on their brain activity over the day and night.

Mice without the GABA chemical developed characteristics similar to a medical condition called mania, in which patients experience restlessness and sleeplessness. In humans these are often also symptoms of bipolar disorder, which affects around 2.4 million people in the UK.

"Wakefulness stimulated by histamine may be too much of a good thing, and so the brain has a built in brake on histamine's wake-inducing actions," said Dr Brickley.

The scientists found that compared with normal mice, those without GABA ran twice as far and twice as fast, and maintained or even increased their overall activity over a 30 minute period.

The mice also stayed awake much longer in the day, when they would otherwise be asleep. When they did sleep, the mice experienced just 65 per cent of the normal amount of non-REM (Rapid Eye Movement) sleep, a heavy sleep state with no dreaming.

"What particularly surprised us was how little the mice were affected by sleep deprivation," said Professor Franks.

"Normally mice that lose 5 hours of sleep would sleep for longer following this deprivation, and we would see a much lower level of activity. These mice kept up their hyperactive state over the following 16 hours they were awake. They didn't appear to need any recovery sleep at all."

The scientists have begun new work with mice to investigate the link between lack of sleep and memory loss. They hope this will lead to a better understanding of the link between poor sleep and mental health issues in humans.
http://www.sciencedaily.com/releases/2015/07/150729092921.htm

Aquariums deliver health and wellbeing benefits

People who spend time watching aquariums and fish tanks could see improvements in their physical and mental wellbeing

July 29, 2015
Science Daily/University of ExeterViewing aquarium displays led to noticeable reductions in blood pressure and heart rate, a research team found in the first study of its kind. They also noted that higher numbers of fish helped to hold people's attention for longer and improve their moods.

In the first study of its kind, experts from the National Marine Aquarium, Plymouth University and the University of Exeter assessed people's physical and mental responses to tanks containing varying levels of fish.

The team found that viewing aquarium displays led to noticeable reductions in blood pressure and heart rate, and that higher numbers of fish helped to hold people's attention for longer and improve their moods.

Whilst spending time in 'natural' environments has been shown to provide calming effects on humans, there has been very little research into the role that underwater settings could have on health and wellbeing. Deborah Cracknell, PhD Student and Lead Researcher at the National Marine Aquarium, conducted the study and believes it provides an important first step in our understanding: "Fish tanks and displays are often associated with attempts at calming patients in doctors' surgeries and dental waiting rooms. This study has, for the first time, provided robust evidence that 'doses' of exposure to underwater settings could actually have a positive impact on people's wellbeing."

The researchers benefited from a unique opportunity in order to conduct their study when the National Marine Aquarium refurbished one of its main exhibits -- in a large 550,000 litre tank -- and began a phased introduction of different fish species.

They were able to assess the mood, heart rate and blood pressure of study participants in precisely the same setting as fish numbers in the exhibit gradually increased.

Dr Sabine Pahl, Associate Professor in Psychology at Plymouth University, said: "While large public aquariums typically focus on their educational mission, our study suggests they could offer a number of previously undiscovered benefits. In times of higher work stress and crowded urban living, perhaps aquariums can step in and provide an oasis of calm and relaxation."

Dr Mathew White, an environmental psychologist at the University of Exeter, said: "Our findings have shown improvements for health and wellbeing in highly managed settings, providing an exciting possibility for people who aren't able to access outdoor natural environments. If we can identify the mechanisms that underpin the benefits we're seeing, we can effectively bring some of the 'outside inside' and improve the wellbeing of people without ready access to nature."
http://www.sciencedaily.com/releases/2015/07/150729215632.htm

Could body posture during sleep affect how your brain clears waste?

August 4, 2015
Science Daily/Stony Brook University
Sleeping in the side position, as compared to on one’s back or stomach, may more effectively remove brain waste and prove to be an important practice to help reduce the chances of developing Alzheimer’s and other neurological diseases, new research suggests.
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By using dynamic contrast magnetic resonance imaging (MRI) to image the brain's glymphatic pathway, a complex system that clears wastes and other harmful chemical solutes from the brain, Stony Brook University researchers Hedok Lee, PhD, Helene Benveniste, MD, PhD, and colleagues, discovered that a lateral sleeping position is the best position to most efficiently remove waste from the brain. In humans and many animals the lateral sleeping position is the most common one. The buildup of brain waste chemicals may contribute to the development of Alzheimer's disease and other neurological conditions. Their finding is published in the Journal of Neuroscience.

Dr. Benveniste, Principal Investigator and a Professor in the Departments of Anesthesiology and Radiology at Stony Brook University School of Medicine, has used dynamic contrast MRI for several years to examine the glymphatic pathway in rodent models. The method enables researchers to identify and define the glymphatic pathway, where cerebrospinal fluid (CSF) filters through the brain and exchanges with interstitial fluid (ISF) to clear waste, similar to the way the body's lymphatic system clears waste from organs. It is during sleep that the glymphatic pathway is most efficient. Brain waste includes amyloid β (amyloid) and tau proteins, chemicals that negatively affect brain processes if they build up.

In the paper, "The Effect of Body Posture on Brain Glymphatic Transport," Dr. Benveniste and colleagues used a dynamic contrast MRI method along with kinetic modeling to quantify the CSF-ISF exchange rates in anesthetized rodents' brains in three positions -- lateral (side), prone (down), and supine (up).

"The analysis showed us consistently that glymphatic transport was most efficient in the lateral position when compared to the supine or prone positions," said Dr. Benveniste. "Because of this finding, we propose that the body posture and sleep quality should be considered when standardizing future diagnostic imaging procedures to assess CSF-ISF transport in humans and therefore the assessment of the clearance of damaging brain proteins that may contribute to or cause brain diseases."

Dr. Benveniste and first-author Dr. Hedok Lee, Assistant Professor in the Departments of Anesthesiology and Radiology at Stony Brook developed the safe posture positions for the experiments. Their colleagues at the University of Rochester, including Lulu Xie, Rashid Deane and Maiken Nedergaard, PhD, used fluorescence microscopy and radioactive tracers to validate the MRI data and to assess the influence of body posture on the clearance of amyloid from the brains.

"It is interesting that the lateral sleep position is already the most popular in human and most animals -- even in the wild -- and it appears that we have adapted the lateral sleep position to most efficiently clear our brain of the metabolic waste products that built up while we are awake," says Dr. Nedergaard. "The study therefore adds further support to the concept that sleep subserves a distinct biological function of sleep and that is to 'clean up' the mess that accumulates while we are awake. Many types of dementia are linked to sleep disturbances, including difficulties in falling asleep. It is increasing acknowledged that these sleep disturbances may accelerate memory loss in Alzheimer's disease. Our findng brings new insight into this topic by showing it is also important what position you sleep in," she explained.

Dr. Benveniste cautioned that while the research team speculates that the human glymphatic pathway will clear brain waste most efficiency when sleeping in the lateral position as compared to other positions, testing with MRI or other imaging methods in humans are a necessary first step.
http://www.sciencedaily.com/releases/2015/08/150804203440.htm

How stress can tweak the brain to sabotage self-control

August 5, 2015
Science Daily/Cell Press
A challenging morning meeting or an interaction with an upset client at work may affect whether we go for that extra chocolate bar at lunch. In a study, researchers placed human volunteers in a similar food choice scenario to explore how stress can alter the brain to impair self-control when we're confronted with a choice.
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"Our findings provide an important step towards understanding the interactions between stress and self-control in the human brain, with the effects of stress operating through multiple neural pathways," says lead author Silvia Maier, of the University of Zurich's Laboratory for Social and Neural Systems Research. "Self-control abilities are sensitive to perturbations at several points within this network, and optimal self-control requires a precise balance of input from multiple brain regions rather than a simple on/off switch." She emphasized that much work still remains, however, to fully understand the mechanisms involved.

In the study, 29 participants underwent a treatment known to induce moderate stress in the laboratory before they were asked to choose between two food options. An additional 22 participants did not undergo the treatment, which involved being observed and evaluated by the experimenter while immersing a hand in an ice water bath for 3 minutes, before choosing between the food options.

All of the participants who were selected for the study were making an effort to maintain a healthy lifestyle, so the study presented them with a conflict between eating a very tasty but unhealthy item and one that is healthy but less tasty.

The scientists found that when individuals chose between different food options after having experienced the stressful ice bath treatment, they overweighed food taste attributes and were more likely to choose an unhealthy food compared with people who were not stressed.

The effects of stress were also visible in the brain. Stressed participants' brains exhibited altered patterns of connectivity between regions including the amygdala, striatum, and the dorsolateral and ventromedial prefrontal cortex, essentially reducing individuals' ability to exercise self-control over food choices. Only some of these changes were associated with cortisol, a hormone commonly linked to stress.

The investigators say that their study indicates that even moderate levels of stress can impair self-control. "This is important because moderate stressors are more common than extreme events and will thus influence self-control choices more frequently and for a larger portion of the population," says senior author Todd Hare. "One interesting avenue for future research will be to determine whether some of the factors shown to protect against structural brain changes following severe stress--such as exercise and social support--can also buffer the effects of moderate stress on decision making," he adds.

There was also a good deal of variation in the degree to which stress affected individuals in the study, so it will be important to investigate why some people are more resilient than others.
http://www.sciencedaily.com/releases/2015/08/150805140245.htm

Rapid eye movements in sleep reset dream 'snapshots' Researchers find eye movements during REM sleep reflect brain activity patterns associated with new images

August 12, 2015
Science Daily/American Friends of Tel Aviv University
Rapid Eye Movement (REM) sleep, the period in which we experience vivid dreams, was discovered by scientists in the 1950s. A new study based on rare neuronal data offers the first scientific evidence of the link between rapid eye movement, dream images, and accelerated brain activity.
http://images.sciencedaily.com/2015/08/150812131924_1_540x360.jpg

A new study based on rare neuronal data offers the first scientific evidence of the link between rapid eye movement, dream images, and accelerated brain activity. When we move our eyes in REM sleep, according to the study, specific brain regions show sudden surges of activity that resemble the pattern that occurs when we are introduced to a new image -- suggesting that eye movements during REM sleep are responsible for resetting our dream "snapshots."

The research, published this week in Nature Communications, was led by Dr. Yuval Nir of Tel Aviv University's Sackler Faculty of Medicine in collaboration with TAU's Prof. Itzhak Fried, also of UCLA and Tel Aviv Medical Center; Thomas Andrillon of the Laboratoire de Sciences Cognitives et Psycholinguistique in Paris; and Dr. Giulio Tononi and Dr. Chiara Cirelli of the University of Wisconsin-Madison.

Deep down in the brain

"Our goal was to examine what happens deep in the human brain during REM sleep, specifically when rapid eye movements occur," said Dr. Nir. "Prof. Fried's trailblazing research with epilepsy patients at UCLA offered a unique opportunity to collect the necessary data -- the activity of neurons located deep inside the human brain."

The research for the study was conducted on 19 epileptic patients at the UCLA Medical Center, who required invasive monitoring of brain activity prior to potential surgical excision of seizure-causing areas of the brain. Electrodes were implanted deep inside the patients' brains to monitor their brain activity over the course of 10 days. These electrodes were able to provide the rare data needed to prove the link between eye movements, dream imagery, and brain activity.

"We focused on the electrical activities of individual neurons in the medial temporal lobe, a set of brain regions that serve as a bridge between visual recognition and memories," said Dr. Nir. "Prof. Fried's prior research had shown that neurons in these regions become active shortly after we view pictures of famous people and places, such as Jennifer Aniston or the Eiffel Tower -- even when we close our eyes and imagine these concepts."

In addition to monitoring the patients' brain activity via intracranial electrodes, the researchers also recorded scalp EEG, muscle tone, and eye movements to identify periods of REM sleep and detect the precise moment of each rapid eye movement.

Images, awake and asleep

"The electrical brain activity during rapid eye movements in sleep were highly similar to those occurring when people were presented with new images," said Dr. Nir. "Many neurons -- including those in the hippocampus -- showed a sudden burst of activity shortly after eye movements in sleep, typically observed when these cells are 'busy' processing new images."

"The research findings suggest that rapid eye movements represent the moment the brain encounters a new image in a dream, similar to the brain activity exhibited when one encounters visual images while awake," Prof. Fried said.

"How and why eye movements occur are important," said Dr. Nir. "And these moments represent privileged windows of opportunity for the study of brain activity."
http://www.sciencedaily.com/releases/2015/08/150812131924.htm