Circadian Rhythms Have Profound Influence On Metabolic Output

Mar. 19, 2012 —

Science Daily/University of California - Irvine

By analyzing the hundreds of metabolic products present in the liver, researchers with the UC Irvine Center for Epigenetics & Metabolism have discovered that circadian rhythms -- our own body clock -- greatly control the production of such key building blocks as amino acids, carbohydrates and lipids.

They identified more than 600 liver-originated metabolites, which are the chemical substances created by metabolism that sustain and promote cell health and growth. Approximately 60 percent of these metabolites were found to be dependent on the endogenous circadian clock -- many more than expected, as only about 15 percent of the body's genes are regulated by it.

Circadian rhythms over 24 hours govern fundamental biological and physiological processes in almost all organisms. They anticipate environmental changes and adapt certain bodily functions to the appropriate time of day. Disruption of these cycles can seriously affect human health.

Center for Epigenetics & Metabolism director Paolo Sassone-Corsi, lead author on the study and one of the world's preeminent researchers on circadian rhythms, said the liver metabolites reveal how the body clock -- through the main circadian gene, CLOCK -- orchestrates the interplay between metabolites and signaling proteins in much the same way a conductor leads a symphony.

"Metabolites and signaling proteins -- like the horns and strings in an orchestra -- need to be perfectly coordinated, and we've found that CLOCK provides that direction," he said.

Since external cues such as day-night lighting patterns and nutrition influence the circadian machinery, metabolites and their relationship to signaling proteins in cells seem to be acutely tied to circadian disruptions. This may help explain, Sassone-Corsi added, some of the primary physiological factors underlying obesity, high cholesterol and metabolic-based diseases like diabetes.

"This interplay has far-reaching implications for human illness and aging, and it is likely vital for proper metabolism," he said. Study results appear this week in the early online edition of the Proceedings of the National Academy of Sciences.

"By identifying the relationship between metabolites and the body clock, we have taken a first step toward a better understanding of how nutrients interact with our metabolism, giving researchers a new opportunity to spot the optimal times for us to get the fullest benefits from the foods we eat and the medications we take," added Kristin Eckel-Mahan, a UCI postdoctoral researcher in biological chemistry and study co-author.

Working with Metabolon Inc., Sassone-Corsi and Eckel-Mahan created the first liver metabolome -- the full set of metabolites. With this information, they partnered with Pierre Baldi, director of UCI's Institute for Genomics & Bioinformatics, and his graduate student Vishal Patel to analyze the data and build CircadiOmics, a Web-based data system that provides detailed profiles of the metabolites and related genes in the liver and the underlying networks through which they interact.

"Within CircadiOmics, we were able to integrate this circadian metabolite data with multiple other data sources to generate the first comprehensive map of the liver metabolome and its circadian oscillations and develop regulatory hypotheses that have been confirmed in the laboratory," said Baldi, Chancellor's Professor of computer science. "CircadiOmics is being expanded with metabolic data about other tissues and conditions and will be invaluable to further our understanding of the interplay between metabolism and circadian rhythms in healthy and diseased states."

http://www.sciencedaily.com/releases/2012/03/120319163803.htm

Scientists Redraw the Blueprint of the Body's Biological Clock

Apr. 5, 2012 —

Science Daily/Salk Institute for Biological Studies

The discovery of a major gear in the biological clock that tells the body when to sleep and metabolize food may lead to new drugs to treat sleep problems and metabolic disorders, including diabetes.

"This fundamentally changes our knowledge about the workings of the circadian clock and how it orchestrates our sleep-wake cycles, when we eat and even the times our bodies metabolize nutrients," says Evans. "Nuclear receptors can be targeted with drugs, which suggests we might be able to target REV-ERBα and β to treat disorders of sleep and metabolism."

Nurses, emergency personnel and others who work shifts that alter the normal 24-hour cycle of waking and sleeping are at much higher risk for a number of diseases, including metabolic disorders such as diabetes.

http://www.sciencedaily.com/releases/2012/04/120405224456.htm

Less Sleep, Disrupted Internal 24-Hour Clock: Higher Risk of Diabetes and Obesity

Apr. 11, 2012 —
Science Daily/Brigham and Women's Hospital
A study by researchers at Brigham and Women's Hospital (BWH) reinforces the finding that too little sleep or sleep patterns that are inconsistent with our body's "internal biological clock" may lead to increased risk of diabetes and obesity. This finding has been seen in short-term lab studies and when observing human subjects via epidemiological studies. However, unlike epidemiological studies, this new study provides support by examining humans in a controlled lab environment over a prolonged period, and altering the timing of sleep, mimicking shift work or recurrent jet lag.

The researchers saw that prolonged sleep restriction with simultaneous circadian disruption decreased the participants' resting metabolic rate. Moreover, during this period, glucose concentrations in the blood increased after meals, because of poor insulin secretion by the pancreas.

According to the researchers, a decreased resting metabolic rate could translate into a yearly weight gain of over 10 pounds if diet and activity are unchanged. Increased glucose concentration and poor insulin secretion could lead to an increased risk for diabetes.

"We think these results support the findings from studies showing that, in people with a pre-diabetic condition, shift workers who stay awake at night are much more likely to progress to full-on diabetes than day workers," said Orfeu M. Buxton, PhD, BWH neuroscientist and lead study author. "Since night workers often have a hard time sleeping during the day, they can face both circadian disruption working at night and insufficient sleep during the day. The evidence is clear that getting enough sleep is important for health, and that sleep should be at night for best effect."
http://www.sciencedaily.com/releases/2012/04/120411144316.htm

Role of Impaired Sleep in Fibromyalgia Pain Explored

Apr. 23, 2012 —

Science Daily/American Pain Society

Patients coping with the complex pain disorder fibromyalgia often have difficulty sleeping, and a new study published in The Journal of Pain reports that despite the negative quality of life implications, poor sleep is not a significant predictor of fibromyalgia pain intensity and duration.

Many fibromyalgia patients complain about poor sleep, and studies have shown that interrupted sleep experienced by individuals with other pain conditions is predictive of next day clinical pain. Also, sleep duration has been shown to predict clinical pain in healthy adults. For this study, a research team from the University of Florida hypothesized that decreased total sleep time would predict higher clinical pain in a sample of patients with fibromyalgia.

http://www.sciencedaily.com/releases/2012/04/120423103724.htm

Intense Light Prevents, Treats Heart Attacks, Study Suggests

Apr. 25, 2012 —
Science Daily/University of Colorado Denver

https://www.sciencedaily.com/images/2012/04/120425143641_1_540x360.jpg
Strong light, or even just daylight, might ease the risk of having a heart attack or suffering damage from one.
Credit: © Iakov Kalinin / Fotolia

There are lots of ways physicians might treat a patient after a heart attack -- certain resuscitation methods, aspirin, clot-busters and more. Now University of Colorado medical school researchers have found a new candidate: Intense light.

"The study suggests that strong light, or even just daylight, might ease the risk of having a heart attack or suffering damage from one," says Tobias Eckle, MD, PhD, an associate professor of anesthesiology, cardiology, and cell and developmental biology at the University of Colorado School of Medicine. "For patients, this could mean that daylight exposure inside of the hospital could reduce the damage that is caused by a heart attack."
http://www.sciencedaily.com/releases/2012/04/120425143641.htm

Change in Attitude May Ease Chronic Pain by Aiding Sleep, Study Suggests

Apr. 26, 2012 —
Science Daily/Johns Hopkins Medicine
Chronic pain sufferers who learn to dwell less on their ailments may sleep better and experience less day-to-day pain, according to results of research conducted on 214 people with chronic face and jaw pain.

"We have found that people who ruminate about their pain and have more negative thoughts about their pain don't sleep as well, and the result is they feel more pain," says Luis F. Buenaver, Ph.D., an assistant professor of psychiatry and behavioral sciences at the Johns Hopkins University School of Medicine and the leader of a study published online in the journal Pain. "If cognitive behavioral therapy can help people change the way they think about their pain, they might end that vicious cycle and feel better without sleeping pills or pain medicine."

Buenaver and his colleagues say the study highlights the function of a major neurological pathway linking negative thinking about pain to increased pain through disturbed sleep. Buenaver says roughly 80 percent of people with chronic pain experience sleep disturbances, and previous studies have shown that people whose sleep patterns are altered are more sensitive to pain. It is also known, he says, that those who focus frequently on their pain and think more negatively about their pain report more debilitating pain. Such "pain catastrophizing," he adds, has been found to be a more robust predictor of worse pain and pain-related disability than depression, anxiety or neuroticism.

For the study, researchers recruited 214 people with myofascial temporomandibular disorder, or TMD, serious facial and jaw pain believed to be stress-related in many cases. The participants were mostly white and female, with an average age of 34 years. Each participant underwent a dental exam to confirm TMD, then filled out questionnaires assessing sleep quality, depression, pain levels and emotional responses to pain, including whether they ruminate or exaggerate it.

Researchers found a direct correlation between negative thinking about pain and poor sleep, as well as with worse pain in the TMD patients.

Buenaver says sleeping pills and painkillers can help, but these pain patients may benefit just as much, if not more, from cognitive behavioral therapy. He says the same may be true of people who suffer from other stress-related ailments without a clear underlying pathology, including fibromyalgia, irritable bowel syndrome and some headaches, neck and back pain.

"It may sound simple, but you can change the way you feel by changing the way you think," Buenaver said.

He and his colleagues currently are studying whether older adults with arthritis and insomnia can benefit from cognitive behavioral therapy for insomnia.

The research is supported by grants from the National Institutes of Health.
http://www.sciencedaily.com/releases/2012/04/120426104343.htm

Some Adults With Sleep Disturbances Are Actually Afraid of the Dark

June 11, 2012 —

Science Daily/American Academy of Sleep Medicine

A small study of Toronto college students is shedding light on a contributing factor of insomnia that might be hard to admit -- an adult fear of the dark.

Nearly half of the students who reported having poor sleep also reported a fear of the dark. Researchers confirmed this objectively by measuring blink responses to sudden noise bursts in light and dark surroundings. Good sleepers became accustomed to the noise bursts but the poor sleepers grew more anticipatory when the lights were down.

"The poor sleepers were more easily startled in the dark compared with the good sleepers," said Taryn Moss, the study's lead author. "As treatment providers, we assume that poor sleepers become tense when the lights go out because they associate the bed with being unable to sleep. Now we're wondering how many people actually have an active and untreated phobia."

http://www.sciencedaily.com/releases/2012/06/120611092343.htm

Top Risk of Stroke for Normal-Weight Adults: Getting Under 6 Hours of Sleep

June 11, 2012 —
Science Daily/American Academy of Sleep Medicine
Habitually sleeping less than six hours a night significantly increases the risk of stroke symptoms among middle-age to older adults who are of normal weight and at low risk for obstructive sleep apnea (OSA), according to a study of 5,666 people followed for up to three years.

The participants had no history of stroke, transient ischemic attack, stroke symptoms or high risk for OSA at the start of the study, being presented June 11 at SLEEP 2012. Researchers from the University of Alabama at Birmingham recorded the first stroke symptoms, along with demographic information, stroke risk factors, depression symptoms and various health behaviors.

After adjusting for body-mass index (BMI), they found a strong association with daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-age to older adults, even beyond other risk factors. The study found no association between short sleep periods and stroke symptoms among overweight and obese participants.

"In employed middle-aged to older adults, relatively free of major risk factors for stroke such as obesity and sleep-disordered breathing, short sleep duration may exact its own negative influence on stroke development," said lead author Megan Ruiter, PhD. "We speculate that short sleep duration is a precursor to other traditional stroke risk factors, and once these traditional stroke risk factors are present, then perhaps they become stronger risk factors than sleep duration alone."

Further research may support the results, providing a strong argument for increasing physician and public awareness of the impact of sleep as a risk factor for stroke symptoms, especially among persons who appear to have few or no traditional risk factors for stroke, she said.

"Sleep and sleep-related behaviors are highly modifiable with cognitive-behavioral therapy approaches and/or pharmaceutical interventions," Ruiter said. "These results may serve as a preliminary basis for using sleep treatments to prevent the development of stroke."

Ruiter and colleagues collected their data as part of the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study, led by George Howard, PhD, of the University of Alabama at Birmingham School of Public Health. REGARDS enrolled 30,239 people ages 45 and older between January 2003 and October 2007, and is continuing to follow them for health changes. The study is funded by the National Institutes of Health (NIH) National Institute of Neurological Disorders and Stroke.
http://www.sciencedaily.com/releases/2012/06/120611092341.htm

In the Hospital, the Noisy Hospital, the Patient Sleeps Tonight?

June 11, 2012 —
Science Daily/Brigham and Women's Hospital
In the hospital it is not only direct patient care, but also the environment that contributes to recovery. A critical component of a healing environment is a peaceful space for a patient to get enough sleep.

However, according to a new study by researchers at Brigham and Women's Hospital (BWH), Massachusetts General Hospital and Cambridge Health Alliance, there are certain noises in a common hospital setting that can disrupt sleep. Such disruption can negatively affect brain activity and cardiovascular function.

The study will be published online in Annals of Internal Medicine on June 12, 2012.

"Hospitals and actually most urban sleep environments are increasingly noise-polluted," said Orfeu Buxton, PhD, BWH Division of Sleep Medicine, co-lead study author. "This study highlights the importance of sleep for restoration and healing that is particularly important for hospitalized patients."

The researchers recruited 12 healthy volunteers to participate in the three-day study which took place in a sleep laboratory. On the first night, the participants slept without any disruption. On the following two nights, they were presented with 14 recorded sounds commonly heard in a hospital setting.

Among the 14 sounds were an intravenous alarm, telephone, ice machine, voices in the hall, outside traffic and a helicopter. The sounds were presented at increasing decibel levels during specific sleep stages.

As expected, the louder the sound the more likely to disrupt sleep. However, there were unexpectedly large differences in sleep disruption based on sound type -- independent of how loud the sound. The researchers found that of all sound types, electronic sounds were most arousing, even at a volume just above a whisper.

Also, a person's sleep stage affected whether sound would lead to arousal. During non-rapid eye movement (NREM) sleep, sound type influenced arousal; whereas, during rapid eye movement (REM) sleep, volume was more influential.

Sleep disruption due to hospital noises also affected cardiovascular function.

"Beyond disturbing sleep itself, we showed that noise-induced sleep disruptions -- even subtle ones, beneath conscious awareness -- lead to temporary elevations in heart rate," said Jeffrey Ellenbogen, MD, director of Sleep Medicine at MGH, co-lead study author. "While these effects were modest in size, our concern is that repeated disruptions, as might occur in a hospital room, may jeopardize the health of our most vulnerable populations."

The study systematically quantifies the disruptive capacity of hospital sounds on sleep, providing evidence that it is important to improve the acoustic environments of new and existing health care facilities to enable the highest quality of care.

"There are several strategies for protecting patient sleep in hospitals," said Jo Solet, PhD, Cambridge Health Alliance, senior study author. "These include acoustic performance guidelines for design and construction, altered night-care routines, and enhanced technologies for clinician communication and medical alarms."
http://www.sciencedaily.com/releases/2012/06/120611193526.htm

Preventing or Better Managing Diabetes May Prevent Cognitive Decline

June 21, 2012 —
Science Daily/University of California - San Francisco
Preventing diabetes or delaying its onset has been thought to stave off cognitive decline -- a connection strongly supported by the results of a 9-year study led by researchers at the University of California, San Francisco (UCSF) and the San Francisco VA Medical Center.

Earlier studies have looked at cognitive decline in people who already had diabetes. The new study is the first to demonstrate that the greater risk of cognitive decline is also present among people who develop diabetes later in life. It is also the first study to link the risk of cognitive decline to the severity of diabetes.

The result is the latest finding to emerge from the Health, Aging, and Body Composition (Health ABC) Study, which enrolled 3,069 adults over 70 at two community clinics in Memphis, TN and Pittsburgh, PA beginning in 1997. All the patients provided periodic blood samples and took regular cognitive tests over time.

When the study began, hundreds of those patients already had diabetes. A decade later, many more of them had developed diabetes, and many also suffered cognitive decline. As described this week in Archives of Neurology, those two health outcomes were closely linked.

People who had diabetes at the beginning of the study showed a faster cognitive decline than people who developed it during the course of the study -- and these people, in turn, tended to be worse off than people who never developed diabetes at all. The study also showed that patients with more severe diabetes who did not control their blood sugar levels as well suffered faster cognitive declines.

"Both the duration and the severity of diabetes are very important factors," said Kristine Yaffe, MD, the lead author of the study. "It's another piece of the puzzle in terms of linking diabetes to accelerated cognitive aging."

An important question for future studies, she added, would be to ask if interventions that would effectively prevent, delay or better control diabetes would also lower people's risk of cognitive impairment later in life.

Yaffe is the Roy and Marie Scola Endowed Chair of Psychiatry; professor in the UCSF departments of Psychiatry, Neurology and Epidemiology and Biostatistics; and Chief of Geriatric Psychiatry and Director of the Memory Disorders Clinic at the San Francisco VA Medical Center.

Diabetes and Cognitive Decline

Diabetes is a chronic and complex disease marked by high levels of sugar in the blood that arise due to problems with the hormone insulin, which regulates blood sugar levels. It is caused by an inability to produce insulin (type 1) or an inability to respond correctly to insulin (type 2).

A major health concern in the United States, diabetes of all types affects an estimated 8.3 percent of the U.S. population -- some 25.8 million Americans -- and costs U.S. taxpayers more than $200 billion annually. In California alone, an estimated 4 million people (one out of every seven adults) has type 2 diabetes and millions more are at risk of developing it. These numbers are poised to explode in the next half century if more is not done to prevent the disease.

Over the last several decades, scientists have come to appreciate that diabetes affects many tissues and organs of the body, including the brain and central nervous system -- particularly because diabetes places people at risk of cognitive decline later in life.

In their study the scientists looked at a blood marker known as "glycosylated hemoglobin," a standard measure of the severity of diabetes and the ability to control it over time. The marker shows evidence of high blood sugar because these sugar molecules become permanently attached to hemoglobin proteins in the blood. Yaffe and her colleagues found that greater levels of this biomarker were associated with more severe cognitive dysfunction.

While the underlying mechanism that accounts for the link between diabetes and risk of cognitive decline is not completely understood, Yaffe said, it may be related to a human protein known as insulin degrading enzyme, which plays an important role in regulating insulin, the key hormone linked to diabetes. This same enzyme also degrades a protein in the brain known as beta-amyloid, a brain protein linked to Alzheimer's disease.
http://www.sciencedaily.com/releases/2012/06/120621195915.htm

Sleep Deprivation Effect On the Immune System Mirrors Physical Stress

June 30, 2012 —
Science Daily/American Academy of Sleep Medicine
Severe sleep loss jolts the immune system into action, reflecting the same type of immediate response shown during exposure to stress, a new study reports.

Researchers in the Netherlands and United Kingdom compared the white blood cell counts of 15 healthy young men under normal and severely sleep-deprived conditions. The greatest changes were seen in the white blood cells known as granulocytes, which showed a loss of day-night rhythmicity, along with increased numbers, particularly at night.

"Future research will reveal the molecular mechanisms behind this immediate stress response and elucidate its role in the development of diseases associated with chronic sleep loss," said Katrin Ackermann, PhD, the study's lead author. "If confirmed with more data, this will have implications for clinical practice and for professions associated with long-term sleep loss, such as rotating shift work."

Previous studies have associated sleep restriction and sleep deprivation with the development of diseases like obesity, diabetes and hypertension. Others have shown that sleep helps sustain the functioning of the immune system, and that chronic sleep loss is a risk factor for immune system impairment.

For this study, white blood cells were categorized and measured from 15 young men following a strict schedule of eight hours of sleep every day for a week. The participants were exposed to at least 15 minutes of outdoor light within the first 90 minutes of waking and prohibited from using caffeine, alcohol or medication during the final three days. All of this was designed to stabilize their circadian clocks and minimize sleep deprivation before the intensive laboratory study.

White blood cell counts in a normal sleep/wake cycle were compared to the numbers produced during the second part of the experiment, in which blood samples were collected during 29 hours of continual wakefulness.

"The granulocytes reacted immediately to the physical stress of sleep loss and directly mirrored the body's stress response," said Ackermann, a postdoctoral researcher at the Eramus MC University Medical Center Rotterdam in the Netherlands.
http://www.sciencedaily.com/releases/2012/07/120701191638.htm

How Stress and Depression Can Shrink the Brain

Aug. 12, 2012 —

Science Daily/Yale University

Major depression or chronic stress can cause the loss of brain volume, a condition that contributes to both emotional and cognitive impairment. Now a team of researchers led by Yale scientists has discovered one reason why this occurs -- a single genetic switch that triggers loss of brain connections in humans and depression in animal models.

"We wanted to test the idea that stress causes a loss of brain synapses in humans," said senior author Ronald Duman, the Elizabeth Mears and House Jameson Professor of Psychiatry and professor of neurobiology and of pharmacology. "We show that circuits normally involved in emotion, as well as cognition, are disrupted when this single transcription factor is activated."

http://www.sciencedaily.com/releases/2012/08/120812151659.htm

Zebrafish Study Explains Why the Circadian Rhythm Affects Your Health

Aug. 28, 2012 —
Science Daily/Linköping Universitet

https://www.sciencedaily.com/images/2012/08/120828073049_1_540x360.jpg
A normal circadian rhythm regulates the genes needed to form the signalling substance VEGF, which in turn is necessary for blood vessel growth (angiogenesis). Light at night disturbs the circadian rhythm, and VEGF cannot be produced – blood vessel growth is inhibited, which can be seen in the microscope images at right.
Credit: Lasse Dahl Jensen

Disruptions to the circadian rhythm can affect the growth of blood vessels in the body, thus causing illnesses such as diabetes, obesity, and cancer, according to a new study from Linköping University and Karolinska Institutet in Sweden.

In an article now being published in the scientific journal Cell Reports, it is demonstrated for the first time that disruption of the circadian rhythm immediately inhibit blood vessel growth in zebra fish embryos.
http://www.sciencedaily.com/releases/2012/08/120828073049.htm

Lights Out? The Dangers of Exposure to Light at Night

Sep. 10, 2012 —
University of Haifa
A panel of world experts discussed "Light Pollution and its Ecophysiological Consequences" and shed light on the extent of the dangers and harm that night-time artificial lighting causes, emphasizing that it is the short wavelength illumination that we have come to know as "eco-friendly illumination" that is causing the most harm (primarily LED lighting).

"The most important thing for us is to raise awareness of the dangers of artificial light at night and we have already come a long way now that the American Medical Association (AMA) recently announced its new policy recognizing adverse health effects of exposure to light at night and encouraging further research into the matter," said Prof. Abraham Haim, a leading authority on light pollution, who coordinated the 21st International Congress of Zoology (ICZ) that was held last week at the University of Haifa, Israel.

The participants were in full agreement that exposure to light at night affects circadian rhythms in nature -- humans, animals and plants -- which when thrown off can result in various illnesses and adverse symptoms.
http://www.sciencedaily.com/releases/2012/09/120910111702.htm

Fruit Flies Reveal New Evolutionary Link for Studying Human Health How They Control Body Temperature Through Circadian Rhythm

Sep. 13, 2012 —
Science Daily/Cincinnati Children's Hospital Medical Center

https://www.sciencedaily.com/images/2012/09/120913123223_1_540x360.jpg
Male common fruit fly (Drosophila melanogaster). Drosophila fruit flies are a common tool in life sciences research for modeling human development and disease. Scientists continue learn more about how molecular processes in fruit flies may have similarities to human development that are conserved through the long process of evolution.
Credit: iStockphoto

New research reveals that fruit flies and mammals may share a surprising evolutionary link in how they control body temperature through circadian rhythm, unlocking new ways to study the insects as models of human development and disease.

The study posted online Sept. 13 by Current Biology reports that similar to people, Drosophila fruit flies -- a common research tool in life sciences -- have a genetically driven internal clock. This circadian clock prompts the insects to seek out warmer or cooler external temperatures according to the time of the day. Cold-blooded creatures change behavior to alter body temperature, usually by seeking out different external temperatures. But fruit flies are the first cold-blooded species to demonstrate their modification of temperature preference behavior is controlled by a circadian clock.

"We show that Drosophila fruit flies exhibit a daily temperature preference rhythm that is low in the morning, high in the evening and that follows a similar pattern as body temperature rhythms in humans," said Fumika N. Hamada, PhD, principal investigator and a researcher in the Division of Pediatric Ophthalmology at Cincinnati Children's Hospital Medical Center. "This study also reports the first systematic analysis of the molecular and neural mechanisms underlying temperature preference rhythm in fruit flies."

The research is important to understanding how regulation of daily body temperature is linked to homeostasis -- the body's ability to maintain a stable internal environment while exposed to changes in the external environment. Failure to manage related stress and maintain homeostasis can lead to abnormal function and disease, Hamada said.

The circadian clock's internal control of body temperature rhythm in warm-blooded mammals, including humans, allows them to maintain homeostasis by regulating sleep and metabolic energy use. The study by Hamada and colleagues is the first to demonstrate that fruit flies have a similar circadian clock system for temperature control, although one more influenced by external temperatures than for mammals. It also is the first to show that Drosophila's behavior modification to adjust body temperature is not controlled by a subset of pacemaker neurons in the brain responsible for locomotor activity.

By subjecting a variety of genetically altered flies to different degrees of light and darkness and then analyzing the insect's brains, the scientists identified a pacemaker neuron in the dorsal region of the fruit fly brain called DN2 that controls the bug's temperature preference rhythm. The function of this neural circuit had previously been unknown, the researchers said.

Hamada said continued study of the newly discovered circadian clock for Drosophila temperature preference rhythm may help explain mechanisms that underlie body temperature control in animals. It also could provide a better understanding of circadian rhythm's changeability from external influences.

Funding support for the study came from the National Institutes of Health (RO1grants GM079182 and NS052854), the March of Dimes, funding from the Precursor Research for Embryonic Science and Technology (PRESTO) program at the Japan Science Technology Agency, and a Trustee Grant from Cincinnati Children's Hospital Medical Center. The first author of the study was Haruna Kaneko, PhD., a member of Hamada's laboratory team. Also collaborating were Paul Hardin, Department of Biology and Center for Biological Clocks Research at Texas A&M University, and Patrick Emery, Department of Neurobiology and Program in Neuroscience, at the University of Massachusetts Medical School.
http://www.sciencedaily.com/releases/2012/09/120913123223.htm

Making Headway On Beta-Blockers and Sleep

Sep. 28, 2012 —
Science Daily/Brigham and Women's Hospital
Over 20 million people in the United States take beta-blockers, a medication commonly prescribed for cardiovascular issues, anxiety, hypertension and more. Many of these same people also have trouble sleeping, a side effect possibly related to the fact that these medications suppress night-time melatonin production. Researchers at Brigham and Women's Hospital (BWH) have found that melatonin supplementation significantly improved sleep in hypertensive patients taking beta-blockers.

"Over the course of three weeks, none of the study participants taking the melatonin showed any of the adverse effects that are often observed with other, classic sleep aids. There were also no signs of 'rebound insomnia' after the participants stopped taking the drug," explained Scheer, who is also an assistant professor of Medicine at Harvard Medical School. "In fact, melatonin had a positive carry-over effect on sleep even after the participants had stopped taking the drug."
http://www.sciencedaily.com/releases/2012/09/120928085629.htm

'I'm Bored!' -- Research On Attention Sheds Light On the Unengaged Mind

Sep. 26, 2012 —
Science Daily/Association for Psychological Science
You're waiting in the reception area of your doctor's office. The magazines are uninteresting. The pictures on the wall are dull. The second hand on the wall clock moves so excruciatingly slowly that you're sure it must be broken. You feel depleted and irritated about being stuck in this seemingly endless moment. You want to be engaged by something -- anything -- when a thought, so familiar from childhood, comes to mind: "I'm bored!"

Although boredom is often seen as a trivial and temporary discomfort that can be alleviated by a simple change in circumstances, it can also be a chronic and pervasive stressor that can have significant consequences for health and well-being.

Boredom at work may cause serious accidents when safety depends on continuous vigilance, as in medical monitoring or long-haul truck driving. On a behavioral level, boredom has been linked with problems with impulse control, leading to overeating and binge eating, drug and alcohol abuse, and problem gambling. Boredom has even been associated with mortality, lending grim weight to the popular phrase "bored to death."

Although it's clear that boredom can be a serious problem, the scientific study of boredom remains an obscure niche of research, and boredom itself is still poorly understood. Even though it's a common experience, boredom hasn't been clearly defined within the scientific community.

Psychological scientist John Eastwood of York University (Ontario, Canada) and colleagues at the University of Guelph and the University of Waterloo wanted to understand the mental processes that underlie our feelings of boredom in order to create a precise definition of boredom that can be applied across a variety of theoretical frameworks. Their new article, which brings together existing research on attention and boredom, is published in the September 2012 issue of Perspectives on Psychological Science, a journal of the Association for Psychological Science.

Drawing from research across many areas of psychological science and neuroscience, Eastwood and colleagues define boredom as "an aversive state of wanting, but being unable, to engage in satisfying activity," which arises from failures in one of the brain's attention networks.

Specifically, we're bored when:
•    We have difficulty paying attention to the internal information (e.g., thoughts or feelings) or external information (e.g., environmental stimuli) required for participating in satisfying activity
•    We're aware of the fact that we're having difficulty paying attention
•    We believe that the environment is responsible for our aversive state (e.g., "this task is boring," "there is nothing to do").

The researchers are confident that integrating the disparate fields of cognitive neuroscience, social psychology, and clinical psychology will produce a more thorough understanding of boredom and attention -- phenomena which are ubiquitous and intimately linked.

Armed with a precise and broadly applicable definition of boredom that gets at the underlying mental processes, the authors identify important next steps in research on boredom. Eastwood and his colleagues hope to help in the discovery and development of new strategies that ease the problems of boredom sufferers and address the potential dangers of cognitive errors that are often associated with boredom.
http://www.sciencedaily.com/releases/2012/09/120926153032.htm

Poorer Lung Health Leads to Age-Related Changes in Brain Function

Oct. 8, 2012 —
Science Daily/Ohio State University
Keeping the lungs healthy could be an important way to retain thinking functions that relate to problem-solving and processing speed in one's later years, new research suggests.

While these two types of "fluid" cognitive functions were influenced by reduced pulmonary function, a drop in lung health did not appear to impair memory or lead to any significant loss of stored knowledge, the study showed.

Researchers used data from a Swedish study of aging that tracked participants' health measures for almost two decades. An analysis of the data with statistical models designed to show the patterns of change over time determined that reduced pulmonary function can lead to cognitive losses, but problems with cognition do not affect lung health.

"The logical conclusion from this is that anything you could do to maintain lung function should be of benefit to fluid cognitive performance as well," said Charles Emery, professor of psychology at Ohio State University and lead author of the study. "Maintaining an exercise routine and stopping smoking would be two primary methods. Nutritional factors and minimizing environmental exposure to pollutants also come into play."

Emery said the analysis also offers insights into the process of human aging. While one theory of aging holds that all functions that slow down do so at the same rate, this study suggests that some aspects of functional decline contribute to a change in the rate of other areas of decline.

"In this case, pulmonary functioning may be contributing to other aspects of functioning," he said. "It starts to speak to the bigger question: What are the processes involved in aging?"

The study is published in the current issue of the journal Psychological Science.

The study sample consisted of 832 participants between ages 50 and 85 who were assessed in up to seven waves of testing across 19 years as part of the Swedish Adoption/Twin Study of Aging. Emery and colleagues used data from pulmonary and cognitive tests conducted in the Swedish study.

Lung function was measured in two ways: forced expiratory volume, or how much air a person can push out of the lungs in one second, and forced vital capacity, the volume of air that is blown out after a deep inhalation.

The Swedish participants also were tested in four cognitive domains that measured verbal abilities associated with stored knowledge, memory, spatial abilities related to problem-solving and processing speed -- which included the ability to write correct responses quickly.

The researchers entered the data into structural equation models that allow for interaction between the components being compared -- in this case, lung function and cognitive function -- as well as the trajectory of the changes over time. These dual-change-score models can be likened to a horse race, Emery said.

"We were looking for effects in both directions. We had previously looked in simpler models and found that pulmonary function did predict cognitive function, but there are some studies that show the opposite direction. It was important for us to go into this with an open mind and use this modeling to test both directions," he said.

This kind of statistical analysis did not quantify the effects, but showed clear trends between a decline in lung function and steeper losses in the two types of "fluid" cognitive function. A small effect was seen on verbal tasks, as well. Pulmonary function change had no influence on memory performance.

The study also showed that changes in cognitive function did not predict lung outcomes.

"In these models the relationship is consistently moving from pulmonary function to cognitive function and not the other way," said Emery, also a professor of internal medicine and an investigator in Ohio State's Institute for Behavioral Medicine Research.

The declines seen in this study are expected with age, he noted. And the elements of cognitive function that were not influenced by lung function -- memory and retrieval of stored knowledge -- are not typically associated with normal aging.

"We know, for example, that the speed at which people can perform the processing task does decline with age. But now we have data that suggests pulmonary function actually predicts that decline," he said.

Though this study does not explain what a loss of pulmonary function does to the brain, the researchers speculated that reduced lung health could lower the availability of oxygen in the blood that could in turn affect chemicals that transmit signals between brain cells.
http://www.sciencedaily.com/releases/2012/10/121008144258.htm

Findings Reveal Brain Mechanisms at Work During Sleep

Oct. 16, 2012 —
Science Daily/Society for Neuroscience
New findings presented today report the important role sleep plays, and the brain mechanisms at work as sleep shapes memory, learning, and behavior. The findings were presented at Neuroscience 2012, the annual meeting of the Society for Neuroscience and the world's largest source of emerging news about brain science and health.

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

Today's findings show that:

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

Other recent findings discussed show:

How sleep enables the remodeling of memories -- including the weakening of irrelevant memories -- and the coherent integration of old and new information (Gina Poe, PhD).
The common logic behind seemingly contradictory theories of how sleep remodels synapses, aiding cognition and memory consolidation (Giulio Tononi, MD, PhD).
"As these research findings show, we cannot underestimate the importance of a good night's sleep," said press conference moderator Clifford Saper, PhD, MD, from the Harvard Medical School, an expert on sleep and its deprivation. "Brain imaging and behavioral studies are illuminating the brain pathways that are blocked or contorted by sleep deprivation, and the risks this poses to learning, memory, and mental health."
http://www.sciencedaily.com/releases/2012/10/121016132115.htm

Chronic Fatigue Syndrome: System Under Stress

Nov. 14, 2012 —
Science Daily/University of New South Wales
Australian researchers have discovered for the first time that reduced heart rate variability -- or changes in heart beat timing -- best predicts cognitive disturbances, such as concentration difficulties commonly reported by people with chronic fatigue syndrome (CFS). This adds to the growing body of evidence linking autonomic nervous system imbalance to symptoms of this poorly understood disorder.

Chronic fatigue syndrome is characterised by medically unexplained, disabling fatigue and neuropsychiatric symptoms of at least six months' duration. The disturbance underlying the symptoms in CFS is still poorly understood.

"We have studied autonomic function in CFS for some time and our findings clearly indicate a loss of integrity in stress-responsive neural and physiological systems in CFS. Patients with this condition are hyper-responsive to challenges arising both from within the body and from the environment," says lead researcher, Associate Professor Ute Vollmer-Conna of the University of New South Wales in Sydney, Australia.

"Even when they sleep, their stress-responsive neural systems are on high alert, signalling that it is not safe to relax. I think this condition may be understood by analogy to post-traumatic stress disorder, just that in CFS the original trauma is most likely a physiological, internal one, such as a severe infection."

In a study of 30 patients with CFS and 40 healthy individuals, UNSW researchers recorded the heart beats of participants (via ECG) and analysed cardiac responses to cognitive challenges, and associations with mental performance outcomes.

The patients with CFS performed with similar accuracy, but they took significantly longer to complete the tests than people without the condition. They also had greater heart rate reactivity; low and unresponsive heart rate variability; and prolonged heart rate-recovery after the cognitive challenge.

Resting heart rate variability (an index of vagus nerve activity) was identified as the only significant predictor of cognitive outcomes, while current levels of fatigue and other symptoms did not relate to cognitive performance.

"This is the first demonstration of an association between reduced cardiac vagal tone and cognitive impairment in CFS. Our findings confirm previous reports of a significant loss of vagal modulation, which becomes particularly apparent when dealing with challenging tasks. The current results are consistent with the notion that CFS represents a 'system under stress'," Associate Professor Vollmer-Conna says.

The findings could lead to new ways to improve cognitive difficulties in people with CFS, including biofeedback assisted retraining of autonomic functioning, the researchers say.
http://www.sciencedaily.com/releases/2012/11/121115133806.htm