HealthMedicine3

Asleep somewhere new, one brain hemisphere keeps watch

April 21, 2016
Science Daily/Brown University
Have trouble sleeping on your first night in a new place? A new study explains what's going on in the brain during that 'first-night effect.'
https://images.sciencedaily.com/2016/04/160421133630_1_540x360.jpg
A rich array of electrodes in the sleep lab allowed for widespread but sensitive sensing of brain activity.
Credit: Michael Cohea/Brown University

The study in Current Biology explains what underlies the "first-night effect," a phenomenon that poses an inconvenience to business travelers and sleep researchers alike. Sleep is often noticeably worse during the first night in, say, a hotel or a sleep lab. In the latter context, researchers usually have to build an "adaptation night" into their studies to do their experiments. This time around, the team at Brown investigated the first-night effect, rather than factoring it out.

"In Japan they say, 'if you change your pillow, you can't sleep,'" said corresponding author Yuka Sasaki, research associate professor of cognitive linguistic and psychological sciences at Brown. "You don't sleep very well in a new place. We all know about it."

Sasaki and lead author Masako Tamaki wanted to figure out why. Over the course of three experiments their team used several methods to precisely measure brain activity during two nights of slumber, a week apart, among a total of 35 volunteers. They consistently found that on the first night in the lab, a particular network in the left hemisphere remained more active than in the right hemisphere, specifically during a deep sleep phase known as "slow-wave" sleep. When the researchers stimulated the left hemisphere with irregular beeping sounds (played in the right ear), that prompted a significantly greater likelihood of waking, and faster action upon waking, than if sounds were played in to the left ear to stimulate the right hemisphere.

In other sleep phases and three other networks tested on the first night, there was no difference in alertness or activity in either hemisphere. On the second night of sleep there was no significant difference between left and right hemispheres even in the "default-mode network" of the left hemisphere, which does make a difference on the first night. The testing, in other words, pinpointed a first-night-only effect specifically in the default-mode network of the left hemisphere during the slow-wave phase.

"To our best knowledge, regional asymmetric slow-wave activity associated with the first-night effect has never been reported in humans," the authors wrote.

To make the novel findings, the researchers used electroencephalography, magnetoencephelography, and magnetic resonance imaging to make unusually high-resolution and sensitive measurements with wide brain coverage.

Despite all that instrumentation, the volunteers did not report any unusual discomfort or anxiety in surveys. They were all screened for general mental health before enrollment in the research to ensure their typical sleep was likely to be normal.

Though the study evidence appears to document and explain the first-night effect, it doesn't answer all the questions about it, Sasaki acknowledged. The researchers only measured the first slow-wave sleep phase, for example. Therefore they don't know whether the left hemisphere keeps watch all night, or works in shifts with the right later in the night.

"It is possible that that the surveillance hemisphere may alternate," Sasaki said.

It's also not clear whether the default-mode network is a lonely watchman. In its day job, which some researchers associate with mind-wandering and daydreaming, it tends to keep running when the brain is otherwise fairly idle. There is evidence from prior studies that it remains more connected to other brain networks than most others during sleep. But because the researchers only measured four networks, they aren't sure what others the default-mode network may work with.

Finally, Sasaki said it's not known yet why the brain only maintains an alert state in just one hemisphere -- whether it's always the left or in alternation with the right. There are many examples among animals, however, of hemispheric asymmetry during slow-wave sleep. Marine mammals exhibit it, Sasaki said, presumably because they regularly need to resurface to breathe, even during sleep.

Now it's been found in humans as a first-night phenomenon.

"The present study has demonstrated that when we are in a novel environment, inter-hemispheric asymmetry occurs in regional slow-wave activity, vigilance and responsiveness, as a night watch to protect ourselves," the study concludes.
https://www.sciencedaily.com/releases/2016/04/160421133630.htm

 

Smartphones uncover how the world sleeps

May 6, 2016
Science Daily/University of Michigan
A pioneering study of worldwide sleep patterns combines math modeling, mobile apps and big data to parse the roles society and biology each play in setting sleep schedules.
https://images.sciencedaily.com/2016/05/160506160105_1_540x360.jpg
The researchers examined how age, gender, amount of light and home country affect the amount of shut-eye people around the globe get, when they go to bed, and when they wake up.
Credit: © theartofphoto / Fotolia

The study, led by University of Michigan mathematicians, used a free smartphone app that reduces jetlag to gather robust sleep data from thousands of people in 100 nations. The researchers examined how age, gender, amount of light and home country affect the amount of shut-eye people around the globe get, when they go to bed, and when they wake up.

Among their findings is that cultural pressures can override natural circadian rhythms, with the effects showing up most markedly at bedtime. While morning responsibilities like work, kids and school play a role in wake-time, the researchers say they're not the only factor. Population-level trends agree with what they would expect from current knowledge of the circadian clock.

"Across the board, it appears that society governs bedtime and one's internal clock governs wake time, and a later bedtime is linked to a loss of sleep," said Daniel Forger, who holds faculty positions in mathematics at the U-M College of Literature, Science, and the Arts, and in the U-M Medical School's Department of Computational Medicine and Bioinformatics. "At the same time, we found a strong wake-time effect from users' biological clocks--not just their alarm clocks. These findings help to quantify the tug-of-war between solar and social timekeeping."

When Forger talks about internal or biological clocks, he's referring to circadian rhythms--fluctuations in bodily functions and behaviors that are tied to the planet's 24-hour day. These rhythms are set by a grain-of-rice-sized cluster of 20,000 neurons behind the eyes. They're regulated by the amount of light, particularly sunlight, our eyes take in.

Circadian rhythms have long been thought to be the primary driver of sleep schedules, even since the advent of artificial light and 9-to-5 work schedules. The new research helps to quantify the role that society plays.

Here's how Forger and colleague Olivia Walch arrived at their findings. Several years ago, they released an app called Entrain that helps travelers adjust to new time zones. It recommends custom schedules of light and darkness. To use the app, you have to plug in your typical hours of sleep and light exposure, and are given the option of submitting your information anonymously to U-M.

The quality of the app's recommendations depended on the accuracy of the users' information, and the researchers say this motivated users to be particularly careful in reporting their lighting history and sleep habits.

With information from thousands of people in hand, they then analyzed it for patterns. Any correlations that bubbled up, they put to the test in what amounts to a circadian rhythm simulator. The simulator--a mathematical model--is based on the field's deep knowledge of how light affects the brain's suprachiasmatic nucleus (that's the cluster of neurons behind the eyes that regulates our internal clocks). With the model, the researchers could dial the sun up and down at will to see if the correlations still held in extreme conditions.

"In the real world, bedtime doesn't behave how it does in our model universe," Walch said. "What the model is missing is how society affects that."

The spread of national averages of sleep duration ranged from a minimum of around 7 hours, 24 minutes of sleep for residents of Singapore and Japan to a maximum of 8 hours, 12 minutes for those in the Netherlands. That's not a huge window, but the researchers say every half hour of sleep makes a big difference in terms of cognitive function and long-term health.

The findings, the researchers say, point to an important lever for the sleep-deprived--a set that the Centers for Disease Control and Prevention is concerned about. A recent CDC study found that across the U.S., one in three adults aren't getting the recommended minimum of seven hours. Sleep deprivation, the CDC says, increases the risk of obesity, diabetes, high blood pressure, heart disease, stroke and stress.

The U-M researchers also found that:

•    Middle-aged men get the least sleep, often getting less than the recommended 7 to 8 hours.
•    Women schedule more sleep than men, about 30 minutes more on average. They go to bed a bit earlier and wake up later. This is most pronounced in ages between 30 and 60.
•    People who spend some time in the sunlight each day tend to go to bed earlier and get more sleep than those who spend most of their time in indoor light.
•    Habits converge as we age. Sleep schedules were more similar among the older-than-55 set than those younger than 30, which could be related to a narrowing window in which older individuals can fall and stay asleep.

Sleep is more important than a lot of people realize, the researchers say. Even if you get six hours a night, you're still building up a sleep debt, says Walch, doctoral student in the mathematics department and a co-author on the paper.

"It doesn't take that many days of not getting enough sleep before you're functionally drunk," she said. "Researchers have figured out that being overly tired can have that effect. And what's terrifying at the same time is that people think they're performing tasks way better than they are. Your performance drops off but your perception of your performance doesn't."

Aside from the findings themselves, the researchers say the work demonstrates that mobile technology can be a reliable way to gather massive data sets at very low cost.

"This is a cool triumph of citizen science," Forger said.
https://www.sciencedaily.com/releases/2016/05/160506160105.htm

 

A narrow band of green light could improve migraines Findings show that pure green light is least likely to exacerbate migraine

May 17, 2016
Science Daily/Oxford University Press
Most migraine and post-traumatic headache sufferers find their headaches get worse in light, leading them to quit their most fundamental daily tasks and seek the comfort of darkness. A new study reveals that exposing these headache sufferers to pure-wavelength green light significantly reduces their photophobia, or sensitivity to light, and can even reduce the severity of their headaches.

Photophobia, associated with more than 80% of migraine attacks, gives migraine sufferers little choice but to isolate themselves in dark rooms, unable to work, care for their family, or pursue everyday activities.

Although photophobia is not as incapacitating as the pain of the headache itself to migraine sufferers, "it is their inability to endure light that most often disables them," says Rami Burstein, Professor of Anesthesia at Beth Israel Deaconess Medical Center (BIDMC) and Harvard Medical School, and lead author of the study.

The new study shows that a narrow band of green light exacerbates migraine significantly less than all other colors of light and that at low intensities it can even reduce the headache itself.

Burstein and his colleagues devised a way to study the effects of different colors of light on headache in patients without visual impairment, after discovering that only blue light hurts blind migraine patients

They asked patients undergoing acute migraine attacks to report any change in headache when exposed to different intensities of blue, green, amber and red light. At high intensity of light (as in a well-lit office) nearly 80% of the patients reported intensification of headache -- in all colours but green. Burstein and his colleagues found, unexpectedly, that green light actually reduced their pain by about 20%.

To understand why green light causes far less pain to these patients, the scientists devised experiments in which they measured the magnitude of the electrical signals generated by the retina (in the eye) and the cortex (in the brain) of these patients in response to each colour of light. They found that green light generated the smallest electrical signals in both the retina and cortex.

Next, they used animal models to show that the thalamus, a brain area that transmits information about light from the eye to the cortex, modifies the information in a way that explains why blue and red light are more painful than amber and why amber is more painful than green.

"My hope is that patients will be able to benefit directly from these findings one day very soon," says Burstein, who is trying to find a way to invent a low-cost light bulb that can emit "pure" (narrow band wavelength) green light at low intensity and sunglasses that block all but this narrow band of pure green light. However, he cautions the current cost of one such light bulb, and the technology, is astronomical.
https://www.sciencedaily.com/releases/2016/05/160517083042.htm

 

Couples study ties anger to heart problems, stonewalling to back pain Study suggests how you argue predicts health problems later in life

May 24, 2016
Science Daily/University of California - Berkeley
If you rage with frustration during a marital spat, watch your blood pressure. If you keep a stiff upper lip, watch your back. New research based on how couples behave during conflicts, suggests outbursts of anger predict cardiovascular problems. Conversely, shutting down emotionally or "stonewalling" during conflict raises the risk of musculoskeletal ailments such as a bad back or stiff muscles.
https://images.sciencedaily.com/2016/05/160524093159_1_540x360.jpg
How do you react to disagreements? It did not take the researchers long to guess which spouses would develop ailments down the road based on how they reacted to disagreements.
Credit: © kmiragaya / Fotolia

New research from the University of California, Berkeley, and Northwestern University, based on how couples behave during conflicts, suggests outbursts of anger predict cardiovascular problems.

Conversely, shutting down emotionally or "stonewalling" during conflict raises the risk of musculoskeletal ailments such as a bad back or stiff muscles.

"Our findings reveal a new level of precision in how emotions are linked to health, and how our behaviors over time can predict the development of negative health outcomes," said UC Berkeley psychologist Robert Levenson, senior author of the study.

The study, published today in the journal Emotion, is based on 20 years of data. It controlled for such factors as age, education, exercise, smoking, alcohol use and caffeine consumption.

Overall, the link between emotions and health outcomes was most pronounced for husbands, but some of the key correlations were also found in wives. It did not take the researchers long to guess which spouses would develop ailments down the road based on how they reacted to disagreements.

"We looked at marital-conflict conversations that lasted just 15 minutes and could predict the development of health problems over 20 years for husbands based on the emotional behaviors that they showed during these 15 minutes," said study lead author Claudia Haase, an assistant professor of human development and social policy at Northwestern University.

The findings could spur hotheaded people to consider such interventions as anger management, while people who withdraw during conflict might benefit from resisting the impulse to bottle up their emotions, the researchers said.

"Conflict happens in every marriage, but people deal with it in different ways. Some of us explode with anger; some of us shut down," Haase said. "Our study shows that these different emotional behaviors can predict the development of different health problems in the long run."

The study is one of several led by Levenson, who looks at the inner workings of long-term marriages. Participants are part of a cohort of 156 middle-aged and older heterosexual couples in the San Francisco Bay Area whose relationships Levenson and fellow researchers have tracked since 1989.

The surviving spouses who participated in the study are now in their 60s, 70s, 80s and even 90s.

Each five years, the couples were videotaped in a laboratory setting as they discussed events in their lives and areas of disagreement and enjoyment.

Their interactions were rated by expert behavioral coders for a wide range of emotions and behaviors based on facial expressions, body language and tone of voice. In addition, the spouses completed a battery of questionnaires that included a detailed assessment of specific health problems.

In this latest study, the researchers focused on the health consequences of anger and an emotion-suppressing behavior they refer to as "stonewalling." The study also looked at sadness and fear as predictors of these health outcomes, but did not find any significant associations.

"Our findings suggest particular emotions expressed in a relationship predict vulnerability to particular health problems, and those emotions are anger and stonewalling," Levenson said.

To track displays of anger, the researchers monitored the videotaped conversations for such behaviors as lips pressed together, knitted brows, voices raised or lowered beyond their normal tone and tight jaws.

To identify stonewalling behavior, they looked for what researchers refer to as "away" behavior, which includes facial stiffness, rigid neck muscles, and little or no eye contact. That data was then linked to health symptoms, measured every five years over a 20-year span.

The spouses who were observed during their conversations to fly off the handle more easily were at greater risk of developing chest pain, high blood pressure and other cardiovascular problems over time.

Alternately, those who stonewalled by barely speaking and avoiding eye contact were more likely to develop backaches, stiff necks or joints and general muscle tension.

"For years, we've known that negative emotions are associated with negative health outcomes, but this study dug deeper to find that specific emotions are linked to specific health problems," Levenson said. "This is one of the many ways that our emotions provide a window for glimpsing important qualities of our future lives."
https://www.sciencedaily.com/releases/2016/05/160524093159.htm

 

Chemotherapy and exercise: The right dose of workout helps side effects

June 4, 2016
Science Daily/University of Rochester Medical Center
Researchers discovered something simple and inexpensive to reduce neuropathy in hands and feet due to chemotherapy -- exercise.

The study, involving more than 300 cancer patients, is to be presented this weekend and honored as a "Best of ASCO" among 5,800 abstracts at the world's largest gathering of oncologists, the American Society of Clinical Oncology (ASCO) annual meeting 2016. More than a dozen other Wilmot scientists also were invited to present data at the meeting.

Investigators in the exercise study directly compared the neuropathic symptoms in non-exercisers to the pain among patients who took part in a specialized six-week walking routine with gentle, resistance-band training at home.

The exercisers reported significantly fewer symptoms of neuropathy--which includes shooting or burning pain, tingling, numbness, and sensitivity to cold--and the effects of exercise seemed to be most beneficial for older patients, said lead author Ian Kleckner, Ph.D., a biophysicist and research assistant professor in Wilmot's Cancer Control and Survivorship program. Kleckner also won an ASCO Merit Award in the pain and symptom management category, and was invited to give a talk about his work.

Not all chemotherapy drugs cause neuropathy, but 60 percent of people with breast cancer and other solid tumors who receive taxanes, vinca alkaloids, and platinum-based chemotherapies will likely suffer this type of side effect, Kleckner said. Neuropathy is more commonly associated with diabetes or nerve damage. No FDA-approved drugs are available to prevent or treat chemotherapy-induced neuropathy, he added.

Wilmot's specialized exercise program, called EXCAP (Exercise for Cancer Patients), was developed several years ago at the UR by Karen Mustian, Ph.D., M.P.H., an associate professor in the Cancer Control program. In recent years she has copyrighted and evaluated EXCAP in several clinical trials. Last year at ASCO, Mustian presented data from a randomized, controlled study of 619 patients showing that EXCAP reduced chronic inflammation and cognitive impairment among people receiving chemotherapy. Kleckner's study involved a subset of patients from Mustian's trial, which is the largest phase 3 confirmatory exercise study ever conducted among cancer patients during chemotherapy. Their work is funded by the National Cancer Institute and Mustian's PEAK lab.

Exercise--as a cancer prevention tool and potential treatment--is a hot topic among the nation's oncologists and their patients.

Kleckner, a longtime drug-free body builder and former college rugby player, said he's committed to understanding more deeply the benefits of exercise for cancer patients. "Exercise is like a sledgehammer because it affects so many biological and psycho-social pathways at the same time--brain circuitry, inflammation, our social interactions--whereas drugs usually have a specific target," he said. "Our next study is being designed to find out how exercise works, how the body reacts to exercise during cancer treatment, and how exercise affects the brain."

Mustian is also giving two talks at ASCO, about the use of exercise in geriatric cancer patients and how innovation can help exercise investigators reach their goals.

"Our program at the University of Rochester, which now includes more than a half-dozen researchers, is becoming a real powerhouse in exercise oncology," Mustian said. "Twelve years ago when we started this work a lot of people said it was not safe for most cancer patients to exercise. Now we know it can be safe when done correctly, and that it has measurable benefits. But more exercise isn't always better for patients who are going through chemo--so it's important to continue our work and find a way to personalize exercise in a way that will help each individual."
https://www.sciencedaily.com/releases/2016/06/160604051004.htm

 

Lighting color affects sleep, wakefulness Green light promotes sleep while blue light delays it, find researchers

June 8, 2016
Science Daily/University of Oxford
A research team has shown how different colors of light could affect our ability to sleep. At the same time they have established that the light-sensitive pigment melanopsin is necessary for the substantial wavelength-dependent effects of light on sleep. The results point to a need to understand the effects of artificial lighting's different color balances.

The researchers, led by Dr Stuart Peirson from Oxford's Sleep and Circadian Neuroscience Institute were aiming to understand why exposing mice to bright light caused two -- physically incompatible -- responses.

Dr Peirson explained: 'When we expose mice to light during the night, it causes them to fall asleep. Yet, at the same time, it also increases levels of corticosterone, a stress hormone produced by the adrenal gland that causes arousal -- wakefulness. We wanted to understand how these two effects were related and how they were linked to a blue light-sensitive pigment called melanopsin, known to play a key role in setting our body clock.'

The team exposed mice to three different colours of light -- violet, blue and green. Based on the existing data about the role of melanopsin in sleep, they expected that the blue light would induce sleep fastest as the wavelength of the blue light (470 nanometres -- nm) was closest to the peak sensitivity of the pigment (around 480nm).

However, it was green light that produced rapid sleep onset -- between 1 and 3 minutes. Blue and violet light delayed sleep -- the onset of sleep taking between 16 and 19 minutes for blue and between 5 and 10 minutes for violet.

Dr Peirson said: 'The results meant that mice exposed to blue light had less sleep than those exposed to violet and green light. We confirmed the effect by testing mice using green and blue light at a time when they would usually be less active.'

To investigate the role of melanopsin, the team performed the same test on mice lacking the pigment. For these mice, the colours had opposite effects -- blue caused rapid sleep onset, while green and violet significantly delayed sleep, showing that melanopsin is necessary for the substantial wavelength-dependent effects of light on sleep.

The researchers also found that while exposure to all three colours of light increased the level of corticosterone stress hormone in ordinary mice, blue light caused a much higher rise. In mice without melanopsin, the response to blue light was greatly reduced. Blocking the effect of corticosterone reduced the sleep-delaying effect, suggesting that the production of this hormone in response to light actively inhibits sleep.

Dr Peirson said: 'This study shows that there are different pathways from the eye to the brain -- one directly regulating sleep and the other increasing arousal. Melanopsin has a more complex role than previously thought, affecting both pathways. This is the first time that it has been shown to regulate adrenal stress responses.

'An obvious caveat of this study is that mice are a nocturnal species that are active during the night. As such, green light may be expected to increase wakefulness rather than increasing sleep in humans. We would therefore predict that blue light will further enhance the wake-promoting effects of light by elevating adrenal stress hormones.

'The results also add to our understanding of the effects of light emitting devices on humans, where recent studies have shown that the blue light from these devices delays sleep. However, as we have shown that there are different pathways in the brain, by which different colours of light have different effects on sleep or wakefulness, we need to understand how the overall colour balance of artificial light could affect people's alertness and sleep.'
https://www.sciencedaily.com/releases/2016/06/160608154233.htm

 

Late sleep timing linked to poorer diet quality, lower physical activity Later sleep timing is associated with higher fast food intake as well as lower vegetable intake, physical activity

June 8, 2016
Science Daily/American Academy of Sleep Medicine
Among healthy adults with a habitual sleep duration of at least 6.5 hours, late sleep timing was associated with higher fast food consumption and lower vegetable intake, particularly among men, as well as lower physical activity, a new study has found.

A new study suggests that among healthy adults with a habitual sleep duration of at least 6.5 hours, late sleep timing was associated with higher fast food consumption and lower vegetable intake, particularly among men, as well as lower physical activity.


Results show that late sleep timing is associated with lower body mass index and is not associated with total caloric intake; however, it remains associated with poorer diet quality, particularly fast food, vegetable and dairy intake.

"Our results help us further understand how sleep timing in addition to duration may affect obesity risk," said principal investigator Kelly Glazer Baron, PhD, associate professor of neurology at the Feinberg School of Medicine at Northwestern University in Chicago, Illinois. "It is possible that poor dietary behaviors may predispose individuals with late sleep to increased risk of weight gain."

The research abstract was published recently in an online supplement of the journal Sleep and will be presented June 12, in Denver at SLEEP 2016, the 30th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

The study group consisted of 96 healthy adults between the ages of 18 and 50 years with sleep duration of 6.5 hours or more. The study involved 7 days of wrist actigraphy to measure sleep, food diaries to measure caloric intake and dietary patterns, and SenseWear arm band monitoring to measure physical activity. Dim light melatonin onset was evaluated in the clinical research unit. Body fat was evaluated using dual axis absorptiometry (DXA). Data were analyzed using correlation and regression analyses controlling for age, sex, sleep duration and sleep efficiency.
https://www.sciencedaily.com/releases/2016/06/160608174254.htm

 

Individuals exposed to blue wavelength lights experienced faster reaction times Blue light exposure has a lasting effect on brain function

June 10, 2016
Science Daily/American Academy of Sleep Medicine
A new study found that blue wavelength light exposure led to subsequent increases in brain activity in the dorsolateral prefrontal cortex (DLPFC) and the ventrolateral prefrontal cortex (VLPFC) when participants were engaging in a cognitive task after cessation of light exposure.

The results also showed that a short single exposure to blue light for half an hour is sufficient to produce measurable changes in reaction times and more efficient responses (answered more items correctly per second) during conditions of greater cognitive load after the light exposure had ended. Moreover, these improvements were directly associated with measurable changes in the activation of the prefrontal cortex.

"Previous studies only focused on the effects of light during the period of exposure. Our study adds to this research by showing that these beneficial effects of blue wavelength light may outlast the exposure period by over 40 minutes," said lead author Anna Alkozei, PhD, postdoctoral fellow in the Department of Psychiatry at the University of Arizona. "Blue-enriched white light could be used in a variety of occupational settings where alertness and quick decision making are important, such as pilot cockpits, operation rooms, or military settings. It could also be used in settings where natural sunlight does not exist, such as the International Space Station. Importantly, our findings suggest that using blue light before having to engage in important cognitive processes may still impact cognitive functioning for over half an hour after the exposure period ended. This may be valuable in a wide range of situations where acute blue light exposure is not a feasible option, such as testing situations."

The research abstract was published recently in an online supplement of the journal Sleep and will be presented Sunday, June 12, 2016 and Wednesday, June 15, 2016 in Denver at SLEEP 2016, the 30th Anniversary Meeting of the Associated Professional Sleep Societies LLC (APSS).

"These findings are important as they link the acute behavioral effects of blue light to enhanced activation of key cortical systems involved in cognition and mental control," said William D. S. Killgore, PhD, the senior author and principal investigator of the project.

The study consisted of 35 healthy adults between the ages of 18 and 3 years. The participants were randomized to receive a 30-minute exposure to either blue (active) or amber (placebo) light immediately followed by a working memory task during functional magnetic resonance imaging (fMRI).
https://www.sciencedaily.com/releases/2016/06/160610094747.htm

 

Dose of nature is just what the doctor ordered

June 23, 2016
Science Daily/University of Queensland
People who visit parks for 30 minutes or more each week are much less likely to have high blood pressure or poor mental health than those who don't, according to new research.

A study led by The University of Queensland (UQ) and the ARC Centre of Excellence for Environmental Decisions (CEED) suggests people might need a minimum "dose of nature."

UQ CEED researcher Dr Danielle Shanahan said parks offered health benefits including reduced risks of developing heart disease, stress, anxiety and depression.

"If everyone visited their local parks for half an hour each week there would be seven per cent fewer cases of depression and nine percent fewer cases of high blood pressure," she said.

"Given that the societal costs of depression alone in Australia are estimated at $A12.6 billion a year, savings to public health budgets across all health outcomes could be immense," she said.

UQ CEED researcher Associate Professor Richard Fuller said the research could transform the way people viewed urban parks.

"We've known for a long time that visiting parks is good for our health, but we are now beginning to establish exactly how much time we need to spend in parks to gain these benefits," he said.

"We have specific evidence that we need regular visits of at least half an hour to ensure we get these benefits."

Dr Shanahan said 40 per cent of Brisbane residents did not visit an urban park in a typical week.

"So how can we encourage people to spend more time in green space?" she said.

"We need more support and encouragement of community activities in natural spaces.

"For example, the Nature Play programs in Queensland, Western Australia and South Australia provide heaps of ideas for helping kids enjoy the great outdoors.

"Our children especially benefit from spending more time outdoors. Kids who grow up experiencing natural environments may benefit developmentally and have a heightened environmental awareness as adults than those who don't."
https://www.sciencedaily.com/releases/2016/06/160623095252.htm

 

Both limited, excess sleep may raise diabetes risk in men Study is the first to show opposite effects of lost sleep in healthy men, women

June 29, 2016
Science Daily/The Endocrine Society
Men who sleep either fewer or more hours than average may face a greater risk of developing diabetes, according to a new study.

More than 29 million people nationwide have diabetes, according to the Endocrine Society's Endocrine Facts and Figures Report. During the last 50 years, the average self-reported sleep duration for individuals has decreased by 1.5 to 2 hours, according to the study's senior author, Femke Rutters, PhD, of the VU Medical Centre in Amsterdam, The Netherlands. The prevalence of diabetes has doubled in the same time period.

"In a group of nearly 800 healthy people, we observed sex-specific relationships between sleep duration and glucose metabolism," said Rutters. "In men, sleeping too much or too little was related to less responsiveness of the cells in the body to insulin, reducing glucose uptake and thus increasing the risk of developing diabetes in the future. In women, no such association was observed."

The cross-sectional study examined the sleep duration and diabetes risk factors in 788 people. The researchers analyzed a subset of participants in the European Relationship between Insulin Sensitivity and Cardiovascular Disease (EGIR-RISC) study, who were healthy adults ranging in age from 30 to 60 years old. Study participants were recruited from 19 study centers in 14 European countries.

Researchers measured the participants' sleep and physical activity using a single-axis accelerometer, a device to track movement. To assess the risk for diabetes, researchers used a device called a hyperinsulinemic-euglycemic clamp to measure how effectively the body used the hormone insulin, which processes sugar in the bloodstream.

The study found that men who slept the least and the most were more likely to have an impaired ability to process sugar compared to men who slept an average amount, about seven hours. The men at either end of the spectrum had higher blood sugar levels than men who got the average amount of sleep.

Women who slept less or more than average, however, were more responsive to the hormone insulin than women who slept the average amount. They also had enhanced function of beta cells -- the cells in the pancreas that produce the hormone insulin. This suggests lost sleep may not put women at increased risk of developing diabetes.

The study is the first to show opposite effects of lost sleep on diabetes risk in men and women. The authors theorized this may be a result of the study population being made up of healthy individuals, rather than those at risk of developing diabetes. The researchers also measured insulin sensitivity and sleep with more sensitive devices than past studies.

"Even when you are healthy, sleeping too much or too little can have detrimental effects on your health," Rutters said. "This research shows how important sleep is to a key aspect of health -- glucose metabolism."
https://www.sciencedaily.com/releases/2016/06/160629135234.htm

 

Poor sleep health could contribute to inflammatory disease

July 6, 2016
Science Daily/Elsevier
Sleep disturbances and long sleep duration are associated with increases in markers of inflammation, a new meta-analysis reports. Common sleep disturbances, such as insomnia, have been associated with increased risk of inflammatory disease and mortality.

"It is important to highlight that both too much and too little sleep appears to be associated with inflammation, a process that contributes to depression as well as many medical illnesses," said Dr. John Krystal, Editor of Biological Psychiatry.

Insufficient sleep is considered a public health epidemic by the Centers for Disease Control and Prevention. Common sleep disturbances, such as insomnia, have been associated with increased risk of inflammatory disease and mortality.

Substances that increase in response to inflammation and circulate in the blood stream, such as C-reactive protein (CRP) and interleukin-6 (IL-6), predict adverse health conditions including cardiovascular events, hypertension, and type 2 diabetes. Many studies have investigated the mechanism behind the association between sleep health and immunity, but variations between studies have made it difficult to understand the effects.

In a recent article, Michael Irwin, Richard Olmstead and Judith Carroll, all of the Cousins Center for Psychoneuroimmunology, UCLA Semel Institute for Neuroscience, University of California, Los Angeles, systematically reviewed existing studies for associations between sleep and inflammatory markers. The meta-analysis examined 72 different articles, which included over 50,000 participants from population-based and clinical studies. The researchers looked at CRP, IL-6, and tumor necrosis factor α (TNFα) as indicators of inflammation.

People with a normal sleep duration get 7-8 hours of shut-eye per night. The analysis showed that sleep disturbance (poor sleep quality or complaints of insomnia) and long sleep duration (more than 8 hours) were associated with increased levels of CRP and IL-6. Shorter sleep duration was associated with increased levels of CRP. No associations were found with TNFα.

According to Irwin, sleep disturbance or insomnia should be regarded as behavioral risk factors for inflammation, similar to the adverse effects of high fat diet or sedentary behavior. Treatments targeting sleep behavior could be a strategy for reversing the inflammation and reducing risk of inflammatory illnesses.

"Together with diet and physical activity, sleep health represents a third component in the promotion of health-span," said Irwin.
https://www.sciencedaily.com/releases/2016/07/160706091735.htm

 

East-west asymmetry of jet lag recovery due to oscillation of brain cells

July 12, 2016
Science Daily/American Institute of Physics
Travelers frequently report experiencing a significantly slower jet lag recovery after an eastward vs. westward flight. While some are quick to dismiss this complaint as being 'all in their head,' new research suggests it may be caused by the oscillation of a certain type of brain cells.
https://images.sciencedaily.com/2016/07/160712115332_1_540x360.jpg
Researchers explored the east-west asymmetry of jet lag recovery.
Credit: © Maxisport / Fotolia

Circadian rhythms, which govern jet lag recovery, are controlled by the synchronization of many neuronal oscillators within the brain. Brain cells within the hypothalamus -- the region of the brain that governs circadian rhythms -- undergo daily cycles of activity.

But after a rapid time zone shift, the brain's oscillatory circadian pacemaker cells are incapable of instantly adjusting to a rhythm appropriate to the new time zone.

So a team of University of Maryland researchers decided to explore whether the east-west asymmetry of jet lag could be understood via mathematical models of these oscillations of cells within the brain, and made some interesting discoveries about the dynamics involved, which they report in the journal Chaos, from AIP Publishing.

Akin to cars racing around a circular track, some of the brain's "circadian pacemaker cells" could complete the circuit faster on their own than others. But due to their mutual interactions sharing the track, these cells tend to form a traffic clump and travel around the track as a group.

"In the absence of a controlling influence, say 'a man with a yellow flag,' the clump of cells completes the circuit within a period of time that may not correspond exactly to one day," explained Michelle Girvan, an associate professor of physics at the University of Maryland's Institute for Physical Science and Technology.

Studies have shown that without daily variations of sunlight acting as that "man with the yellow flag," or traffic controller, the brain's circadian pacemaker cells complete their cycle in a time slightly longer than a day.

"Our mathematical model is based on this type of picture," Girvan said. "We start by explicitly modeling the dynamics of a large number of cells, and then use a novel method for simplifying this very large system to a single equation that can be easily analyzed."

What did they discover? While an average person's natural circadian rhythm is believed to slightly exceed 24 hours, the team's model indicated that this small amount of time -- on the order of 30 minutes -- is significant and can explain the rather large east-west asymmetry for jet lag recovery, which can equate to days when traveling across several times zones.

Their model also explains how individuals can experience a differing severity in response to rapid cross-time-zone travel. Since the neuronal oscillator cells of different individuals may have different properties, in the absence of regulation by the diurnal pattern of sunlight, "some people may have a natural circadian rhythm with a period of 24.5 hours, while others may have longer or shorter natural rhythms," Girvan elaborated. "Our model suggests that the difference between a person's natural period and 24 hours controls how they experience jet lag."

The team hopes that the mechanistic insights provided by their simplified model "can serve as a guide for developing more in-depth qualitative approaches, as well as strategies to combat circadian rhythm disruptions due to rapid cross-time-zone travel, shift work, or blindness," Girvan said.
https://www.sciencedaily.com/releases/2016/07/160712115332.htm

 

Is artificial lighting making us sick? New evidence in mice

July 14, 2016
Science Daily/Cell Press
Along with eating right and exercising, people should consider adding another healthy habit to their list: turning out the lights. That's according to a new study showing many negative health consequences for mice kept under conditions of constant light for a period of months.
https://images.sciencedaily.com/2016/07/160714134753_1_540x360.jpg
New findings suggest that more care should be taken in considering the amount of light exposure people get.
Credit: © meepoohyaphoto / Fotolia

"Our study shows that the environmental light-dark cycle is important for health," says Johanna Meijer of Leiden University Medical Center in the Netherlands. "We showed that the absence of environmental rhythms leads to severe disruption of a wide variety of health parameters."

Those parameters included pro-inflammatory activation of the immune system, muscle loss, and early signs of osteoporosis. The researchers say that the observed physiological changes were all indicative of "frailty" as is typically seen in people or animals as they age. But there was some more encouraging news, too.

"The good news is that we subsequently showed that these negative effects on health are reversible when the environmental light-dark cycle is restored," Meijer says.

To investigate the relationship between a loss of the light-dark cycle and disease, Meijer and colleagues, including Eliane Lucassen, exposed mice to light around the clock for 24 weeks and measured several major health parameters. Studies of the animals' brain activity showed that the constant light exposure reduced the normal rhythmic patterns in the brain's central circadian pacemaker of the suprachiasmatic nuclei (SCN) by 70 percent.

Strikingly, the disruption to normal light and dark patterns and the circadian rhythm led to a reduction in the animals' skeletal muscle function as measured in standard tests of strength. Their bones showed signs of deterioration, and the animals entered a pro-inflammatory state normally observed only in the presence of pathogens or other harmful stimuli. After the mice were returned to a standard light-dark cycle for 2 weeks, the SCN neurons rapidly recovered their normal rhythm, and the animals' health problems were reversed.

The findings suggest that more care should be taken in considering the amount of light exposure people get, particularly those who are aging or otherwise vulnerable. That's important given that 75 percent of the world's population is exposed to light during the night. Constant light exposure is very common in nursing homes and intensive care units, and many people also work into the night.

"We used to think of light and darkness as harmless or neutral stimuli with respect to health," Meijer says. "We now realize this is not the case based on accumulating studies from laboratories all over the world, all pointing in the same direction. Possibly this is not surprising as life evolved under the constant pressure of the light-dark cycle. We seem to be optimized to live under these cycles, and the other side of the coin is that we are now affected by a lack of such cycles."

The bottom line, according to the researchers is "light exposure matters."

They say they now plan to perform more in-depth analysis of the influence of distorted light-dark cycles on the immune system. They'd also like to investigate possible health benefits to patients exposed to more normal conditions of light and dark.
https://www.sciencedaily.com/releases/2016/07/160714134753.htm

 

New theory explains how beta waves arise in the brain

July 25, 2016
Science Daily/Brown University
A team of neuroscientists proposes a new theory -- backed by data from people, animal models and computational simulation -- to explain how beta waves emerge in the brain.
https://images.sciencedaily.com/2016/07/160725192354_1_540x360.jpg
Jones led a team that has posited a new theory of how beta rhythms arise in the brain, backed by evidence from humans, animal models and computer simulation.
Credit: Brown University

Beta rhythms, or waves of brain activity with an approximately 20 Hz frequency, accompany vital fundamental behaviors such as attention, sensation and motion and are associated with some disorders such as Parkinson's disease. Scientists have debated how the spontaneous waves emerge, and they have not yet determined whether the waves are just a byproduct of activity, or play a causal role in brain functions. Now in a new paper led by Brown University neuroscientists, they have a specific new mechanistic explanation of beta waves to consider.

The new theory, presented in the Proceedings of the National Academy of Sciences, is the product of several lines of evidence: external brainwave readings from human subjects, sophisticated computational simulations and detailed electrical recordings from two mammalian model organisms.

"A first step to understanding beta's causal role in behavior or pathology, and how to manipulate it for optimal function, is to understand where it comes from at the cellular and circuit level," said corresponding author Stephanie Jones, research associate professor of neuroscience at Brown University. "Our study combined several techniques to address this question and proposed a novel mechanism for spontaneous neocortical beta. This discovery suggests several possible mechanisms through which beta may impact function."

Making waves

The team started by using external magnetoencephalography (MEG) sensors to observe beta waves in the human somatosensory cortex, which processes sense of touch, and the inferior frontal cortex, which is associated with higher cognition.

They closely analyzed the beta waves, finding they lasted at most a mere 150 milliseconds and had a characteristic wave shape, featuring a large, steep valley in the middle of the wave.

The question from there was what neural activity in the cortex could produce such waves. The team sought to recreate the waves using a computer model of a cortical circuitry, made up of a multilayered cortical column that contained multiple cell types across different layers. Importantly, the model was designed to include a cell type called pyramidal neurons, whose activity is thought to dominate the human MEG recordings.

They found that they could closely replicate the shape of the beta waves in the model by delivering two kinds of excitatory synaptic stimulation to distinct layers in the cortical columns of cells: one that was weak and broad in duration to the lower layers, contacting spiny dendrites on the pyramidal neurons close to the cell body; and another that was stronger and briefer, lasting 50 milliseconds (i.e., one beta period), to the upper layers, contacting dendrites farther away from the cell body. The strong distal drive created the valley in the waveform that determined the beta frequency.

Meanwhile they tried to model other hypotheses about how beta waves emerge, but found those unsuccessful.

With a model of what to look for, the team then tested it by looking for a real biological correlate of it in two animal models. The team analyzed measurements in the cortex of mice and rhesus macaques and found direct confirmation that this kind of stimulation and response occurred across the cortical layers in the animal models.

"The ultimate test of the model predictions is to record the electrical signals inside the brain," Jones said. "These recordings supported our model predictions."

Beta in the brain

Neither the computer models nor the measurements traced the source of the excitatory synaptic stimulations that drive the pyramidal neurons to produce the beta waves, but Jones and her co-authors posit that they likely come from the thalamus, deeper in the brain. Projections from the thalamus happen to be in exactly the right places needed to deliver signals to the right positions on the dendrites of pyramidal neurons in the cortex. The thalamus is also known to send out bursts of activity that last 50 milliseconds, as predicted by their theory.

With a new biophysical theory of how the waves emerge, the researchers hope the field can now investigate whether beta rhythms affect or merely reflect behavior and disease. Jones's team in collaboration with Professor of neuroscience Christopher Moore at Brown is now testing predictions from the theory that beta may decrease sensory or motor information processing functions in the brain. New hypotheses are that the inputs that create beta may also stimulate inhibitory neurons in the top layers of the cortex, or that they may may saturate the activity of the pyramidal neurons, thereby reducing their ability to process information; or that the thalamic bursts that give rise to beta occupy the thalamus to the point where it doesn't pass information along to the cortex.

Figuring this out could lead to new therapies based on manipulating beta, Jones said.

"An active and growing field of neuroscience research is trying to manipulate brain rhythms for optimal function with stimulation techniques," she said. "We hope that our novel finding on the neural origin of beta will help guide research to manipulate beta, and possibly other rhythms, for improved function in sensorimotor pathologies."
https://www.sciencedaily.com/releases/2016/07/160725192354.htm

 

No dream: Electric brain stimulation during sleep can boost memory

July 28, 2016
Science Daily/University of North Carolina Health Care
For the first time, scientists report using transcranial alternating current stimulation, or tACS, to target a specific kind of brain activity during sleep and strengthen memory in healthy people.
https://images.sciencedaily.com/2016/07/160728143247_1_540x360.jpg
Could brain stimulation during sleep boost memory?
Credit: © elnariz / Fotolia

When you sleep, your brain is busy storing and consolidating things you learned that day, stuff you'll need in your memory toolkit tomorrow, next week, or next year. For many people, especially those with neurological conditions, memory impairment can be a debilitating symptom that affects every-day life in profound ways. For the first time, UNC School of Medicine scientists report using transcranial alternating current stimulation, or tACS, to target a specific kind of brain activity during sleep and strengthen memory in healthy people.


The findings, published in the journal Current Biology, offer a non-invasive method to potentially help millions of people with conditions such as autism, Alzheimer's disease, schizophrenia, and major depressive disorder.

For years, researchers have recorded electrical brain activity that oscillates or alternates during sleep; they present as waves on an electroencephalogram (EEG). These waves are called sleep spindles, and scientists have suspected their involvement in cataloging and storing memories as we sleep.

"But we didn't know if sleep spindles enable or even cause memories to be stored and consolidated," said senior author Flavio Frohlich, PhD, assistant professor of psychiatry and member of the UNC Neuroscience Center. "They could've been merely byproducts of other brain processes that enabled what we learn to be stored as a memory. But our study shows that, indeed, the spindles are crucial for the process of creating memories we need for every-day life. And we can target them to enhance memory."

This marks the first time a research group has reported selectively targeting sleep spindles without also increasing other natural electrical brain activity during sleep. This has never been accomplished with tDCS -- transcranial direct current stimulation -- the much more popular cousin of tACS in which a constant stream of weak electrical current is applied to the scalp.

During Frohlich's study, 16 male participants underwent a screening night of sleep before completing two nights of sleep for the study.

Before going to sleep each night, all participants performed two common memory exercises -- associative word-pairing tests and motor sequence tapping tasks, which involved repeatedly finger-tapping a specific sequence. During both study nights, each participant had electrodes placed at specific spots on their scalps. During sleep one of the nights, each person received tACS -- an alternating current of weak electricity synchronized with the brain's natural sleep spindles. During sleep the other night, each person received sham stimulation as placebo.

Each morning, researchers had participants perform the same standard memory tests. Frohlich's team found no improvement in test scores for associative word-pairing but a significant improvement in the motor tasks when comparing the results between the stimulation and placebo night.

"This demonstrated a direct causal link between the electric activity pattern of sleep spindles and the process of motor memory consolidation." Frohlich said.

Caroline Lustenberger, PhD, first author and postdoctoral fellow in the Frohlich lab, said, "We're excited about this because we know sleep spindles, along with memory formation, are impaired in a number of disorders, such as schizophrenia and Alzheimer's. We hope that targeting these sleep spindles could be a new type of treatment for memory impairment and cognitive deficits."

Frohlich said, "The next step is to try the same intervention, the same type of non-invasive brain stimulation, in patients that have known deficits in these spindle activity patterns."

Frohlich's team previously used tACS to target the brain's natural alpha oscillations to boost creativity. This was a proof of concept. It showed it was possible to target these particular brain waves, which are prominent as we create ideas, daydream, or meditate. These waves are impaired in people with neurological and psychiatric illnesses, including depression.
https://www.sciencedaily.com/releases/2016/07/160728143247.htm

 

Brain areas altered during hypnotic trances identified

July 28, 2016
Science Daily/Stanford University Medical Center
By scanning the brains of subjects while they were hypnotized, researchers were able to see the neural changes associated with hypnosis.
https://images.sciencedaily.com/2016/07/160728100926_1_540x360.jpg
Stanford researchers found changes in three areas of the brain that occur when people are hypnotized. (Stock image)
Credit: © WavebreakmediaMicro / Fotolia

Your eyelids are getting heavy, your arms are going limp and you feel like you're floating through space. The power of hypnosis to alter your mind and body like this is all thanks to changes in a few specific areas of the brain, researchers at the Stanford University School of Medicine have discovered.

The scientists scanned the brains of 57 people during guided hypnosis sessions similar to those that might be used clinically to treat anxiety, pain or trauma. Distinct sections of the brain have altered activity and connectivity while someone is hypnotized, they report in a study that will be published online July 28 in Cerebral Cortex.

"Now that we know which brain regions are involved, we may be able to use this knowledge to alter someone's capacity to be hypnotized or the effectiveness of hypnosis for problems like pain control," said the study's senior author, David Spiegel, MD, professor and associate chair of psychiatry and behavioral sciences.

A serious science

For some people, hypnosis is associated with loss of control or stage tricks. But doctors like Spiegel know it to be a serious science, revealing the brain's ability to heal medical and psychiatric conditions.

"Hypnosis is the oldest Western form of psychotherapy, but it's been tarred with the brush of dangling watches and purple capes," said Spiegel, who holds the Jack, Samuel and Lulu Willson Professorship in Medicine. "In fact, it's a very powerful means of changing the way we use our minds to control perception and our bodies."

Despite a growing appreciation of the clinical potential of hypnosis, though, little is known about how it works at a physiological level. While researchers have previously scanned the brains of people undergoing hypnosis, those studies have been designed to pinpoint the effects of hypnosis on pain, vision and other forms of perception, and not the state of hypnosis itself.

"There had not been any studies in which the goal was to simply ask what's going on in the brain when you're hypnotized," said Spiegel.

Finding the most susceptible

To study hypnosis itself, researchers first had to find people who could or couldn't be hypnotized. Only about 10 percent of the population is generally categorized as "highly hypnotizable," while others are less able to enter the trancelike state of hypnosis. Spiegel and his colleagues screened 545 healthy participants and found 36 people who consistently scored high on tests of hypnotizability, as well as 21 control subjects who scored on the extreme low end of the scales.

Then, they observed the brains of those 57 participants using functional magnetic resonance imaging, which measures brain activity by detecting changes in blood flow. Each person was scanned under four different conditions -- while resting, while recalling a memory and during two different hypnosis sessions.

"It was important to have the people who aren't able to be hypnotized as controls," said Spiegel. "Otherwise, you might see things happening in the brains of those being hypnotized but you wouldn't be sure whether it was associated with hypnosis or not."

Brain activity and connectivity

Spiegel and his colleagues discovered three hallmarks of the brain under hypnosis. Each change was seen only in the highly hypnotizable group and only while they were undergoing hypnosis.

First, they saw a decrease in activity in an area called the dorsal anterior cingulate, part of the brain's salience network. "In hypnosis, you're so absorbed that you're not worrying about anything else," Spiegel explained.

Secondly, they saw an increase in connections between two other areas of the brain -- the dorsolateral prefrontal cortex and the insula. He described this as a brain-body connection that helps the brain process and control what's going on in the body.

Finally, Spiegel's team also observed reduced connections between the dorsolateral prefrontal cortex and the default mode network, which includes the medial prefrontal and the posterior cingulate cortex. This decrease in functional connectivity likely represents a disconnect between someone's actions and their awareness of their actions, Spiegel said. "When you're really engaged in something, you don't really think about doing it -- you just do it," he said. During hypnosis, this kind of disassociation between action and reflection allows the person to engage in activities either suggested by a clinician or self-suggested without devoting mental resources to being self-conscious about the activity.

Treating pain and anxiety without pills

In patients who can be easily hypnotized, hypnosis sessions have been shown to be effective in lessening chronic pain, the pain of childbirth and other medical procedures; treating smoking addiction and post-traumatic stress disorder; and easing anxiety or phobias. The new findings about how hypnosis affects the brain might pave the way toward developing treatments for the rest of the population -- those who aren't naturally as susceptible to hypnosis.

"We're certainly interested in the idea that you can change people's ability to be hypnotized by stimulating specific areas of the brain," said Spiegel.

A treatment that combines brain stimulation with hypnosis could improve the known analgesic effects of hypnosis and potentially replace addictive and side-effect-laden painkillers and anti-anxiety drugs, he said. More research, however, is needed before such a therapy could be implemented.
https://www.sciencedaily.com/releases/2016/07/160728100926.htm

 

Insomnia? Oversleeping? Both may increase your risk of stroke

August 3, 2016
Science Daily/American Academy of Neurology
There is growing evidence that sleep disorders like insomnia and sleep apnea are related to stroke risk and recovery from stroke, according to a recent literature review.

Based on the review, the authors recommend that people who have had a stroke or a mini-stroke, called a transient ischemic attack, be screened for sleep disorders.

"Although sleep disorders are common after a stroke, very few stroke patients are tested for them," said study author Dirk M. Hermann, MD, of University Hospital Essen in Essen, Germany. "The results of our review show that should change, as people with sleep disorders may be more likely to have another stroke or other negative outcomes than people without sleep problems, such as having to go to a nursing home after leaving the hospital."

The researchers also recommend that sleep apnea be treated with a continuous positive airway pressure machine (CPAP), based on evidence that shows that its use can improve outcomes after stroke.

For the literature review, the researchers examined dozens of studies that looked at the link between sleep disturbances and stroke. They then combined the data of multiple studies in a meta-analysis.

Sleep disorders generally fall into two categories: sleep breathing problems and sleep-wake disorders. Sleep breathing problems like sleep apnea disrupt breathing while asleep. Sleep-wake disorders like insomnia and restless leg syndrome affect the amount of time spent asleep.

The review found evidence linking sleep breathing problems with stroke risk and recovery. Sleep-wake disorders may increase stroke risk and harm recovery, although there is less evidence to prove so.

Due to this lack of evidence and to possible side effects, the researchers are cautious to recommend treatment of sleep-wake disorders with drugs.
https://www.sciencedaily.com/releases/2016/08/160803214246.htm

 

Dreaming also occurs during non rapid eye movement sleep

August 9, 2016
Science Daily/Aalto University
Measurements demonstrated that the brain activity of people who dream during NREM sleep, compared to people who do not dream in NREM sleep, is closer to brain activity of awake people.
https://images.sciencedaily.com/2016/08/160809121817_1_540x360.jpg
Dr. Gosseries and Dr. Nieminen are preparing a subject (Bjørn Erik Juel) for the experiment.
Credit: Johan Frederik Storm

Researchers from Aalto University and the University of Wisconsin utilised a TMS-EEG device, which combines transcranial magnetic stimulation and EEG, to examine how the brain activity of people in the restful non-rapid eye movement (NREM) sleep is affected by whether they dream or do not dream.

When the NREM sleep of subjects had lasted at least three minutes, researchers gave magnetic pulses that induced a weak electric field and activated neurons. After a series of pulses, the subject was woken with an alarm sound, and they were then asked whether they had dreamed and to describe the content of the dream.

'It is traditionally thought that dreaming occurs only in REM sleep. However, as also our study demonstrates, subjects woken from NREM sleep are also able to give accounts of their dreams in more than half of cases,' Post-doctoral Researcher Jaakko Nieminen from Aalto University explains.

'EEG showed that the deterministic brain activity produced by magnetic pulses was notably shorter in people who did not dream, i.e. were unconscious, than in people who had dreamt. We also observed that the longer the story about the dream, the more the subject's EEG resembled that measured from people who were awake,' Dr Nieminen explains.

Assessment of consciousness may help in treatment of brain injury patients

Dr Nieminen performed the measurements with his research colleague Olivia Gosseries at the University of Wisconsin-Madison Center for Sleep and Consciousness, which is headed by Giulio Tononi. The measurements were carried out during a period of over 40 nights and a total of 11 subjects participated. Due to sleeping difficulties and other challenges, reliable measurements could only be acquired from six subjects. During the night, subjects were woken a maximum of 16 times.

'Consciousness in different physiological states (e.g. during wakefulness, sleep, anesthesia and vegetative state) has previously been researched with TMS-EEG measurements. We wanted to eliminate all other differences related to the different states as thoroughly as possible, and for this reason we focused on the narrow physiological state of NREM sleep,' Dr Nieminen notes.

Transcranial magnetic stimulation is already utilised in such things as the treatment of depression and pain. According to Dr Nieminen, in the future the precise data provided by TMS-EEG measurements on the state of consciousness may also help in the treatment of brain injury patients who are unable to communicate.
https://www.sciencedaily.com/releases/2016/08/160809121817.htm

 

Light, caffeine improve driver alertness

August 9, 2016
Science Daily/Queensland University of Technology
Bright light combined with caffeine can improve driving performance and alertness of chronically sleep deprived young drivers, according to a road safety study.

The use of smartphones and tablet computers during evening hours has previously been associated with sleep disturbances in humans. A new study from Uppsala University now shows that daytime light exposure may be a promising means to combat sleep disturbances associated with evening use of electronic devices. The findings are published in the scientific journal Sleep Medicine.
Dr Shamsi Shekari, from QUT's Centre for Accident Research & Road Safety -- Queensland (CARRS-Q) presented her findings at the 2016 International Conference on Traffic and Transport Psychology held in Australia this month.

CARRS-Q and Griffith University co-hosted the event which brought together international experts from across the globe to share the latest in road safety research with the aim of reducing road trauma.

As part of her PhD, Dr Shekari tested the novel and potentially effective use of bright light, using commercially available light glasses that emit a shortwave blue-green light, and caffeinated chewing gum on young drivers aged 18-25 in a driving simulator to see if it increased alertness during daytime driving.

"Light therapy is being used to adjust a person's circadian rhythm in shift workers and pilots and offers the potential to reduce sleepiness," she said.

"The study found there was a significant effect on driving performance, mostly when caffeine was used alone or combined with light.

"Drivers who were given just caffeine, or light and caffeine together had decreased side to side movement of the steering wheel and the vehicle, indicating better control of the vehicle and higher alertness.

"Drivers who were feeling some signs of sleepiness after sleep loss, felt less sleepy after receiving either light or caffeine, and even felt rather alert after receiving the combination of both."

Dr Shekari said the two-week study included monitoring sleep-wake patterns, with a normal eight hours of time in bed in the first week being reduced by to seven hours in the second week to produce chronic sleep deprivation in the participants.

"On the last three days participants took test sessions which involved recording their brain and heart activity, reaction times, assessment of their sleepiness and two 50km-long simulated drives each day," she said.

"To compare the effectiveness of the countermeasures, all participants were provided with inactive chewing gum and light in the first drive and randomised active chewing gum and light in the second drive."

Dr Shekari said driver sleepiness accounted for 20 per cent of all crashes in developed countries, and young drivers were at an increased risk of chronic sleep deprivation.

"This is due to later brain development and social factors such as friends, work patterns and increased use of drugs and alcohol, all of which impact on sleep," she said.

Dr Shekari said while her study had revealed promising results of the use of light and caffeine to improve driver alertness, more research was needed.

"CARRS-Q is now undertaking a study on the effect of sleep loss and caffeine on driving where we want to learn more specifically about the effect of daytime sleepiness and caffeine on driver performance," she said.
https://www.sciencedaily.com/releases/2016/08/160809122734.htm

 

Plenty of light during daytime reduces the effect of blue light screens on night sleep

August 10, 2016
Science Daily/Uppsala University
The use of smartphones and tablet computers during evening hours has previously been associated with sleep disturbances in humans. A new study now shows that daytime light exposure may be a promising means to combat sleep disturbances associated with evening use of electronic devices.

The use of blue light emitting devices during evening hours has been shown to interfere with sleep in humans. In a new study from Uppsala University involving 14 young females and males, neuroscientists Christian Benedict and Frida Rångtell sought to investigate the effects of evening reading on a tablet computer on sleep following daytime bright light exposure.

'Our main finding was that following daytime bright light exposure, evening use of a self-luminous tablet for two hours did not affect sleep in young healthy students', says Frida Rångtell, first author and PhD student at the Department of Neuroscience at Uppsala University.

'Our results could suggest that light exposure during the day, e.g. by means of outdoor activities or light interventions in offices, may help combat sleep disturbances associated with evening blue light stimulation. Even if not examined in our study, it must however be kept in mind that utilizing electronic devices for the sake of checking your work e-mails or social network accounts before snoozing may lead to sleep disturbances as a result of emotional arousal', says senior author Christian Benedict, associate professor at the Department of Neuroscience.
https://www.sciencedaily.com/releases/2016/08/160810104246.htm

 

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