Four timely facts about our biological clocks
October 30, 2014
Science Daily/NIH, National Institute of General Medical Sciences (NIGMS)
After you roll your clocks back by an hour, you may feel tired. That's because our bodies — more specifically, our circadian rhythms — need a little time to adjust. These daily cycles are run by a network of tiny, coordinated biological clocks. One researcher tracks circadian rhythm research being conducted in labs across the country, and he shares a few timely details about our internal clocks.
Mike Sesma of the National Institutes of Health tracks circadian rhythm research being conducted in labs across the country, and he shares a few timely details about our internal clocks:
1. They're incredibly intricate. Biological clocks are composed of genes and proteins that operate in a feedback loop. Clock genes contain instructions for making clock proteins, whose levels rise and fall in a regular cyclic pattern. This pattern in turn regulates the activity of the genes. Many of the results from circadian rhythm research this year have uncovered more parts of the molecular machinery that fine-tune the clock.
2. Every organism has them -- from algae to zebras. Many of the clock genes and proteins are similar across species, allowing researchers to make important findings about human circadian processes by studying the clock components of organisms like fruit flies, bread mold and plants.
3. Whether we're awake or asleep, our clocks keep ticking. While they might get temporarily thrown off by changes in light or temperature, our clocks usually can reset themselves.
4. Nearly everything about how our body works is tied to biological clocks. Our clocks influence alertness, hunger, metabolism, fertility, mood and other physiological conditions. For this reason, clock dysfunction is associated with various disorders, including insomnia, diabetes and depression. Even drug efficacy has been linked to our clocks: Studies have shown that some drugs might be more effective if given earlier in the day.
Learn more:
Circadian Rhythms Fact Sheet: http://www.nigms.nih.gov/Education/Pages/Factsheet_CircadianRhythms.aspx
Resetting Our Clocks: New Details About How the Body Tells Time Article from Inside Life Science: http://publications.nigms.nih.gov/insidelifescience/resetting-our-clocks.html
http://www.sciencedaily.com/releases/2014/10/141030213700.htm
Long term shift work linked to impaired brain power
November 3, 2014
Science Daily/BMJ-British Medical Journal
Long term shift work is linked to impaired brain power, finds research. The impact (for rotating shift patterns, at least) was stronger after a period of 10 or more years of exposure. And although the effects can be reversed, recovery may take at least five years, the findings suggest.
The second set of analyses looked at the impact of working a rotating shift pattern and found that compared with those who had never worked this type of shift, those who had, and had done so for 10 or more years, had lower global cognitive and memory scores -- equivalent to 6.5 years of age related cognitive decline.Finally, the researchers looked at whether stopping shift work was linked to a recovery in cognitive abilities.
The results indicated that it was possible to regain cognitive abilities after stopping shift work, but that this took at least five years, processing speeds excepted.
This is an observational study so no definitive conclusions can be drawn about cause and effect, but the disruption of the body clock as a result of shiftwork could generate physiological stressors, which may in turn affect the functioning of the brain, suggest the researchers.
Other research has also linked vitamin D deficiency caused by reduced exposure to daylight, to poorer cognition, they point out."The cognitive impairment observed in the present study may have important safety consequences not only for the individuals concerned, but also for society as a whole, given the increasing number of jobs in high hazard situations that are performed at night," warn the researchers.
At the very least the findings suggest that monitoring the health of people who have worked shift patterns for 10 years would be worth while, they say.
http://www.sciencedaily.com/releases/2014/11/141103192034.htm
High rate of insomnia during early recovery from addiction
November 5, 2014
Science Daily/Wolters Kluwer Health: Lippincott Williams and Wilkins
Insomnia is a "prevalent and persistent" problem for patients in the early phases of recovery from the disease of addiction — and may lead to an increased risk of relapse, according to a results of a recent study.
"Treating sleep disturbance in early recovery may have considerable impact on maintenance of sobriety and quality of life," according to Dr. Nicholas Rosenlicht of University of San Francisco and colleagues. They summarize the benefits of treatment, highlighting the role of effective behavioral approaches. The lead author was Katherine A. Kaplan, PhD, of Stanford University School of Medicine.
More generally, clinicians should be aware prescribing medications to treat insomnia may be "incongruent with or unpalatable to" treatment programs focusing on abstinence. In one survey, many addiction medicine specialists said they'd be reluctant to prescribe any medication to patients with sleep problems.
This belief has made behavioral approaches more widely used to treat patients with insomnia during recovery. In particular, evidence supports the use of cognitive-behavioral therapy (CBT). This multicomponent approach includes daily sleep diaries and questionnaires to gather information on the patient's insomnia and progress during treatment; and education on sleep and the effects of substances, including "sleep hygiene" practices to promote good sleep.
http://www.sciencedaily.com/releases/2014/11/141105140706.htm
Moderate drinking is healthy only for some people
November 10, 2014
Science Daily/University of Gothenburg
A new study confirms that moderate alcohol consumption can protect against coronary heart disease. But only for the 15% of the population that have a particular genotype.
The study included 618 Swedes with coronary heart disease and a control group of 3,000 healthy subjects. The subjects were assigned to various categories based on the amount of alcohol they consumed (ethanol intake). Meanwhile, they were tested in order to identify a particular genotype (CETP TaqIB) that previous studies had found to play a role in the health benefits of alcohol consumption.
Protective effect The results, which have been published in Alcohol, confirm the findings of the earlier studies. Moderate consumption of alcohol helps protect people with the genotype against coronary heart disease.
"In other words, moderate drinking has a protective effect among only 15% of the general population," says Professor Dag Thelle, Professor Emeritus at Sahlgrenska Academy, University of Gothenburg.
Sweeping advice Thus, the researchers believe that the advice frequently given about the health benefits of moderate alcohol consumption is far too sweeping.
"Moderate drinking alone does not have a strong protective effect," says Professor Lauren Lissner, who also participated in the study. "Nor does this particular genotype. But the combination of the two appears to significantly reduce the risk of coronary heart disease."
http://www.sciencedaily.com/releases/2014/11/141110090723.htm
Anxiety can damage brain, research shows
November 10, 2014
Science Daily/Baycrest Centre for Geriatric Care
People with mild cognitive impairment are at increased risk of converting to Alzheimer's disease within a few years, but a new study warns the risk increases significantly if they suffer from anxiety.
"Our findings suggest that clinicians should routinely screen for anxiety in people who have memory problems because anxiety signals that these people are at greater risk for developing Alzheimer's," said Dr. Linda Mah, principal investigator on the study, clinician-scientist with Baycrest's Rotman Research Institute, and assistant professor in the Department of Psychiatry at the University of Toronto. Dr. Mah is also a co-investigator in a multi-site study lead by the Centre for Addiction and Mental Health, and partially funded by federal dollars (Brain Canada), to prevent Alzheimer's in people with late-life depression or MCI who are at high risk for developing the progressive brain disease.
"While there is no published evidence to demonstrate whether drug treatments used in psychiatry for treating anxiety would be helpful in managing anxiety symptoms in people with mild cognitive impairment or in reducing their risk of conversion to Alzheimer's, we think that at the very least behavioural stress management programs could be recommended. In particular, there has been research on the use of mindfulness-based stress reduction in treating anxiety and other psychiatric symptoms in Alzheimer's --and this is showing promise," said Dr. Mah.
http://www.sciencedaily.com/releases/2014/11/141110124352.htm
Could depression actually be a form of infectious disease?
November 14, 2014
Science Daily/Stony Brook University
Major depressive disorder (MDD) should be re-conceptualized as an infectious disease, according to a professor. A new article suggests that major depression may result from parasitic, bacterial, or viral infection. The article presents examples that illustrate possible pathways by which these microorganisms could contribute to the etiology of MDD.
MDD remains highly prevalent disease with some 15 to 20 percent of the population experiencing MDD at some point. Recurrence is common, and pharmacological treatments have not changed. Because the causal aspects of the disease are not clearly defined, research to find causes remains paramount to help improve treatments.
http://www.sciencedaily.com/releases/2014/11/141114124307.htm
Effect of once-daily, low-dose aspirin on cardiovascular death, other outcomes
November 17, 2014
Science Daily/JAMA - Journal of the American Medical Association
Researchers examined whether once-daily, low-dose aspirin would reduce the total number of cardiovascular (CV) events (death from CV causes, nonfatal heart attack or stroke) compared with no aspirin in Japanese patients 60 years or older with hypertension, diabetes, or poor cholesterol or triglyceride levels.
The World Health Organization estimates that annual global mortality due to cardiovascular diseases (including heart attack and stroke) will approach 25 million by 2030. A recent study of trends in cardiovascular disease in Japan indicated that there has been, from 1960 to 2000, a steep increase in the prevalence of glucose intolerance, hypercholesterolemia, and obesity, probably due to the adoption of Western diets and lifestyles. By 2030, it is estimated that 32 percent of the Japanese population will be 65 years or older. Prevention of atherosclerotic cardiovascular diseases is an important public health priority in Japan due to an aging population, according to background information in the article.
This study included 14,464 patients (60 to 85 years of age) with hypertension, dyslipidemia (poor cholesterol or triglyceride levels), or diabetes mellitus who were randomized to aspirin (100 mg/d) or no aspirin in addition to ongoing medications. The patients were recruited by primary care physicians at 1,007 clinics in Japan. The study was terminated early by the data monitoring committee after a median follow-up of 5.02 years based on likely futility.
The researchers found that there was no statistically significant difference between the two groups in time to the primary end point (a composite of death from cardiovascular causes, nonfatal stroke, and nonfatal heart attack). At 5 years after randomization, the cumulative primary event rate was similar in participants in the aspirin group (2.77 percent) and those in the no aspirin group (2.96 percent).
Aspirin significantly reduced incidence of nonfatal heart attack and transient ischemic attack, and significantly increased the risk of extracranial hemorrhage requiring transfusion or hospitalization.
The authors write that despite inconsistent evidence for the benefit of aspirin in primary prevention of cardiovascular events, the benefits in secondary prevention are well documented, including in Japanese patients. "There is also a growing body of evidence to suggest benefits for aspirin in the prevention of colorectal and other cancers, and the prevention of cancer recurrence, including in the Japanese population. Reduction in the incidence of colorectal cancer may influence the overall benefitrisk profile of aspirin. Further analyses of [this] study data are planned, including analysis of deaths associated with cancers, to allow more precise identification of the patients for whom aspirin treatment may be most beneficial."
http://www.sciencedaily.com/releases/2014/11/141117125559.htm
Scientists prevent memory problems caused by sleep deprivation
November 18, 2014
Science Daily/University of Pennsylvania
Scientists have found that a particular set of cells in a small region of the brain are responsible for memory problems after sleep loss. By selectively increasing levels of a signaling molecule in these cells, the researchers prevented mice from having memory deficits.
In a new study, published in the Journal of Neuroscience, a team led by scientists from the University of Pennsylvania found that a particular set of cells in a small region of the brain are responsible for memory problems after sleep loss. By selectively increasing levels of a signaling molecule in these cells, the researchers prevented mice from having memory deficits.
"The challenge following this important study," Abel said, "was to determine if the impact of sleep deprivation was mediated by particular regions of the brain and particular neural circuits. We suspected that the hippocampus, the brain region that mediates spatial navigation and contextual memory, was critical."
"Thinking about people who do shift work or doctors who work long hours, if we can tackle the cognitive problems that result from sleep loss, that would be a great thing," Havekes said.
http://www.sciencedaily.com/releases/2014/11/141118182458.htm
Mental disorders due to permanent stress?
November 21, 2014
Science Daily/Ruhr-Universitaet-Bochum
Activated through permanent stress, immune cells will have a damaging effect on and cause changes to the brain. This may result in mental disorders. Medical researchers are studying the effects of permanent stress on the immune system.
Stress activates the immune system
The team focused mainly on a certain type of phagocytes, namely microglia. Under normal circumstances, they repair synapses between nerves cells in the brain and stimulate their growth. Once activated, however, microglia may damage nerve cells and trigger inflammation processes. The studies carried out in Bochum have shown that the more frequently microglia get triggered due to stress, the more they are inclined to remain in the destructive mode -- a risk factor for mental diseases such as schizophrenia.
Susceptibility for stress effects varies from individual to individual
Not every individual who is under permanent stress will develop a mental disorder.
Prof Juckel's team suspects the cause to go back to the embryonic stage. US researchers demonstrated as far back as the 1950s that children born of mothers who contracted true viral influenza during pregnancy were seven times as likely to suffer schizophrenia later in life.
The researchers from Bochum confirmed this hypothesis in animal models. Now, they a striving to research into the mechanism that makes people susceptible to this disease. "The embryo undergoes some kind of immune response which has far-reaching consequences and presumably shapes the future immune system," says Dr Astrid Friebe from the LWL clinic.
http://www.sciencedaily.com/releases/2014/11/141121082907.htm
Sleep apnea linked to poor aerobic fitness
November 24, 2014
Science Daily/University of California, San Diego Health Sciences
People with moderate to severe obstructive sleep apnea may have an intrinsic inability to burn high amounts of oxygen during strenuous aerobic exercise, according to a new study.
People who suffer from apnea are more likely to be obese and thus would be expected to be less fit as well. The researchers, however, found that apnea patients had a reduced aerobic fitness, even compared with those of similar body mass indices.
"Encouraging patients to exercise more is part of the story, but that is not the whole story," said lead author Jeremy Beitler, MD, assistant clinical professor in pulmonary and critical care medicine. "We believe the sleep apnea itself causes structural changes in muscle that contributes to their difficulty exercising."
http://www.sciencedaily.com/releases/2014/11/141124125058.htm
Relationship between sleep cycle, cancer found
December 3, 2014
Science Daily/Virginia Tech
People who work around the clock could actually be setting themselves back, according to biologists. A protein responsible for regulating the body's sleep cycle, or circadian rhythm, also protects the body from developing sporadic forms of cancers, researchers have found.
"The protein, known as human period 2, has impaired function in the cell when environmental factors, including sleep cycle disruption, are altered," said Carla Finkielstein, an associate professor of biological sciences in the College of Science, Fralin Life Science Institute affiliate, and a Virginia Bioinformatics Institute Fellow.
Results from these studies may help develop new, more effective prevention strategies for populations at risk due to circadian disruption, such as women working night shifts.
"These findings highlight the complexity of the circadian-controlled network and emphasize its physiological relevance for human health and for new therapeutic interventions," Finkielstein said.
"Over the past two decades we've learned a great deal about the inner workings of the circadian clock, the internal timepiece that controls our sleep:wake cycle and a whole host of other daily bodily rhythms," said Ignacio Provencio, a professor of biology at the University of Virginia who was not involved with the study.
"The Finkielstein lab discovered that a molecular gear of this clock interacts directly with a well-studied protein whose role is to suppress tumor formation. This remarkable finding is likely to provide insight into how disruption of the internal clock can lead to cancer."
Finkielstein has long studied the connection between circadian rhythms and cancer development, particularly the incidence of breast cancer in women who work night shifts like nurses and flight attendants.
http://www.sciencedaily.com/releases/2014/12/141203142432.htm
Don’t worry, be happy: Just go to bed earlier
December 4, 2014
http://images.sciencedaily.com/2014/12/141204091129-large.jpg
Science Daily/Springer Science+Business Media
Researchers link late evenings to repetitive negative thoughts. When you go to bed, and how long you sleep at a time, might actually make it difficult for you to stop worrying. So say researchers, who found that people who sleep for shorter periods of time and go to bed very late at night are often overwhelmed with more negative thoughts than those who keep more regular sleeping hours.
People are said to have repetitive negative thinking when they have bothersome pessimistic thoughts that seem to repeat in their minds. They feel as though they have little control over these contemplations. They also tend to worry excessively about the future, delve too much into the past, and experience annoying intrusive thoughts.
Such thoughts are often typical of people suffering from generalized anxiety disorder, major depressive disorder, post-traumatic stress disorder, obsessive compulsive disorder, and social anxiety disorder. These individuals also tend to have sleep problems.
Previous studies have linked sleep problems with such repetitive negative thoughts, especially in cases where someone does not get enough shut eye. Nota and Coles set out to replicate these studies, and to further see if there's any link between having such repetitive thoughts and the actual time when someone goes to bed.
"Making sure that sleep is obtained during the right time of day may be an inexpensive and easily disseminable intervention for individuals who are bothered by intrusive thoughts," remarks Nota.
The findings also suggest that sleep disruption may be linked to the development of repetitive negative thinking. Nota and Coles therefore believe that it might benefit people who are at risk of developing a disorder characterized by such intrusive thoughts to focus on getting enough sleep.
"If further findings support the relation between sleep timing and repetitive negative thinking, this could one day lead to a new avenue for treatment of individuals with internalizing disorders," adds Coles. "Studying the relation between reductions in sleep duration and psychopathology has already demonstrated that focusing on sleep in the clinic also leads to reductions in symptoms of psychopathology."
http://www.sciencedaily.com/releases/2014/12/141204091129.htm
Suicide risk linked to insomnia, alcohol use
December 22, 2014
Science Daily/American Academy of Sleep Medicine
Insomnia symptoms mediate the relationship between alcohol use and suicide risk, and that this mediation is moderated by gender, a new study demonstrates for the first time. The study suggests that the targeted assessment and treatment of specific sleep problems may reduce the risk of suicide among those who use alcohol.
The study found that alcohol use was significantly associated with suicide risk among women. However, further analysis revealed that insomnia symptoms explained a significant proportion of the relationship between alcohol and suicide risk. For men, there was no direct effect of alcohol use on suicide risk, but there was a significant indirect effect of alcohol use increasing suicide risk through insomnia symptoms.
"These results are important as they help demonstrate that alcohol use is associated with an increase in suicide risk, and that this increase may be partially due to insomnia symptoms," said principal investigator Michael Nadorff, PhD, assistant professor at Mississippi State University in Starkville, Miss. "By better understanding this relationship, and the mechanisms associated with increased risk, we can better design interventions to reduce suicide risk."
According to the American Academy of Sleep Medicine, about 10 percent of people have chronic insomnia disorder, which involves a sleep disturbance and associated daytime symptoms that have been present for at least three months. About 15 to 20 percent of adults have short-term insomnia disorder. Both types of insomnia are more common in women than in men.
http://www.sciencedaily.com/releases/2014/12/141222131358.htm
Light-emitting e-readers before bedtime can adversely impact sleep
December 22, 2014
http://images.sciencedaily.com/2014/12/141222131348-large.jpg
Science Daily/Brigham and Women's Hospital
Use of a light-emitting electronic device (LE-eBook) in the hours before bedtime can adversely impact overall health, alertness, and the circadian clock which synchronizes the daily rhythm of sleep to external environmental time cues, according to new research that compared the biological effects of reading an LE-eBook compared to a printed book.
"We found the body's natural circadian rhythms were interrupted by the short-wavelength enriched light, otherwise known as blue light, from these electronic devices," said Anne-Marie Chang, PhD, corresponding author, and associate neuroscientist in BWH's Division of Sleep and Circadian Disorders.
"Participants reading an LE-eBook took longer to fall asleep and had reduced evening sleepiness, reduced melatonin secretion, later timing of their circadian clock and reduced next-morning alertness than when reading a printed book."
Previous research has shown that blue light suppresses melatonin, impacts the circadian clock and increase alertness, but little was known about the effects of this popular technology on sleep. The use of light emitting devices immediately before bedtime is a concern because of the extremely powerful effect that light has on the body's natural sleep/wake pattern, and may thereby play a role in perpetuating sleep deficiency.
"In the past 50 years, there has been a decline in average sleep duration and quality," stated Charles Czeisler, PhD, MD, FRCP, chief, BWH Division of Sleep and Circadian Disorders. "Since more people are choosing electronic devices for reading, communication and entertainment, particularly children and adolescents who already experience significant sleep loss, epidemiological research evaluating the long-term consequences of these devices on health and safety is urgently needed."
http://www.sciencedaily.com/releases/2014/12/141222131348.htm
Stress can be a factor for developing diabetes, autoimmune diseases
January 2, 2015
Science Daily/Investigación y Desarrollo
Recurring stress can trigger insulin resistance, hypertension, abdominal fat deposition, researchers say.
Stress is an ability of humans to fight or flee when faced with problems affecting the individual. By changes in the organism, adaptation to various physical conditions is achieved: burns, bruises, bleeding or psychosocial traumas.
Is the route by which the body tries to solve a problem, but when the situation becomes recurrent, stress can trigger diseases such as diabetes, depression, insulin resistance, hypertension, abdominal fat deposition and other autoimmune diseases, said Siegfried Miracle Lopez, chief of endocrinology at the Advanced Immunology Center in Hospital Angeles Lomas.
Type II diabetes is a disease caused by a systemic imbalance. The body is in a constant state called homeostasis, in which a balance between the external medium variants like the weather, temperature, light, night and internal factors as blood pressure, heart rate, performance of the kidney, liver, pancreas and lungs.
When an imbalance of homeostasis and angiostasis arises, (alteration in immune and hormone systems) and the body can not adapt to it, this is when diseases are generated, in the case of type II diabetes the elevation of blood glucose is causing the stress.
It is very difficult to examine a disease without thinking that there is a mechanism that detonated it. By experiencing stress, homeostasis can be affected, especially if it is constant and is not giving the body time to re-adapt and reach a neutral point, this situation is what generates sufferings.
"Type II diabetes has immune, genetic and environmental components, is a multifactorial disease, thereby in medical schools we are no longer teaching diabetes as a disease but of a group of diseases characterized by glucose elevation, which causes inflammatory processes affecting the organs and immune system disorders that impair circulation, eyes and kidneys," explained the specialist.
For this reason, the chief of endocrinology at the institution, emphasized how a current problem is that doctors specialize in small parts of the body, because the organism is very complex, but a fragmented study may lead to misdiagnosis.
"The problem is wanting to stay in our micro universe specialty, missing the right diagnosis, hence arises the need for a multidisciplinary team together of several specialists such as neurologists, endocrinologists, urologists, psychologists, rheumatologists, oncologists , otolaryngologist, to analyze the case at the same time and achieve a better diagnosis and treatment," concluded Miracle Lopez.
http://www.sciencedaily.com/releases/2015/01/150102071555.htm
Rotating night shift work can be hazardous to your health
January 5, 2015
Science Daily/Elsevier
Night shift work has been consistently associated with higher risk for cardiovascular disease (CVD) and cancer. In 2007 the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption.
In a new study, researchers found that women working rotating night shifts for five or more years appeared to have a modest increase in all-cause and CVD mortality and those working 15 or more years of rotating night shift work appeared to have a modest increase in lung cancer mortality. These results add to prior evidence of a potentially detrimental effect of rotating night shift work on health and longevity.
Sleep and the circadian system play an important role in cardiovascular health and antitumor activity. There is substantial biological evidence that night shift work enhances the development of cancer and CVD, and contributes to higher mortality.
An international team of researchers investigated possible links between rotating night shift work and all-cause, CVD, and cancer mortality in a study of almost 75,000 registered U.S. nurses. Using data from the Nurses' Health Study (NHS), the authors analyzed 22 years of follow-up and found that working rotating night shifts for more than five years was associated with an increase in all-cause and CVD mortality. Mortality from all causes appeared to be 11% higher for women with 6-14 or ≥15 years of rotating night shift work. CVD mortality appeared to be 19% and 23% higher for those groups, respectively. There was no association between rotating shift work and any cancer mortality, except for lung cancer in those who worked shift work for 15 or more years (25% higher risk).
The NHS, which is based at Brigham and Women's Hospital, began in 1976, with 121,700 U.S. female nurses aged 30-55 years, who have been followed up with biennial questionnaires. Night shift information was collected in 1988, at which time 85,197 nurses responded. After excluding women with pre-existing CVD or other than non-melanoma skin cancer, 74,862 women were included in this analysis. Defining rotating shift work as working at least three nights per month in addition to days or evenings in that month, respondents were asked how many years they had worked in this way. The prespecified categories were never, 1-2, 3-5, 6-9, 10-14, 15-19, 20-29, and ≥30 years.
According to Eva S. Schernhammer, MD, DrPH, currently Associate Professor of Medicine, Harvard Medical School, and Associate Epidemiologist, Department of Medicine, Brigham and Women's Hospital, Boston, this study "is one of the largest prospective cohort studies worldwide with a high proportion of rotating night shift workers and long follow-up time. A single occupation (nursing) provides more internal validity than a range of different occupational groups, where the association between shift work and disease outcomes could be confounded by occupational differences."
Comparing this work with previous studies, she continues, "These results add to prior evidence of a potentially detrimental relation of rotating night shift work and health and longevity...To derive practical implications for shift workers and their health, the role of duration and intensity of rotating night shift work and the interplay of shift schedules with individual traits (e.g., chronotype) warrant further exploration."
http://www.sciencedaily.com/releases/2015/01/150105081757.htm
International research effort gives neuroscientists better feeling about sense of touch
January 6, 2015
Science Daily/Carnegie Mellon University
Our sense of touch is one we often take for granted, until our leg falls asleep and we aren't able to stand, or when we experience acute pain. The sense of touch also has been taken for granted in neuroscience, where it's the sense scientists know the least about. For the first time, researchers have linked a group of neurons to a specific type of somatosensation, a finding that can open the door for a heightened understanding about our sense of touch.
"Somatosensation is critical. You can somewhat overcome losing your sense of smell, sight, taste, or hearing. But if you lose your sense of touch, you wouldn't be able to sit up or walk. You wouldn't be able to feel pain," said Barth, a professor of biological sciences and a member of Carnegie Mellon's BrainHubSM research initiative. "We know less about the features that make up our rich tactile experience than we do about any other sense, yet it's such a critical sense."
Somatosensation, which is another word for our sense of touch, occurs in a number of forms, like feeling texture, temperature, pressure, pain or vibration. It's responsible for proprioception, which helps us know where we are within our environment. It tells us if our feet are firmly planted on the floor, or if we're holding a paper cup tightly enough that it won't slip out of our hand, but loosely enough that we don't crush the cup. Scientists know a good deal about the molecular receptors that mediate the different types of somatosensation, but they know little about how touch is represented in the brain.
"When someone gets pricked by a pin, we know how information about that sensation travels from the skin to the spinal cord. But what happens in the brain has been much less clear -- it seems like all different sorts of touch information get jumbled together," said Barth, who also is a member of the joint Carnegie Mellon/University of Pittsburgh Center for the Neural Basis of Cognition (CNBC).
"This is the first time we've been able to visualize neurons in the somatosensory cortex that 'like' a specific tactile stimulus," Barth said. "It shows that neurons are individuals. They have different jobs to do in the cortex. In this case these neurons had a special feature: they responded when all of the mouse's whiskers moved at once."
They also found that the neurons in question received direct synaptic input from the posteromedial nucleus of the brain's thalamus. This shows that the neurons that react to the puff-of-air stimulus have a dedicated, unique sub-network of connections that enable them to communicate with one another and amplify the information they are receiving from the stimulus.
"Now that we have isolated the neural underpinnings of a certain feature, we can try to manipulate and change the interactions between cells. Can we train the mouse and strengthen the connections between neurons? What happens to perception if we remove the connections? It's really the frontier of truly understanding somatosensory function," Barth said.
This research also could lead to work that will identify how somatosensory information is coded, which could be used to incorporate sensory information into brain-machine interfaces. This could allow robotic limbs and prosthetics to actively sense and receive tactile input.
http://www.sciencedaily.com/releases/2015/01/150106095033.htm
Expressing anger linked with better health in some cultures
January 7, 2015
Science Daily/Association for Psychological Science
In the US and many Western countries, people are urged to manage feelings of anger or suffer its ill effects -- but new research with participants from the US and Japan suggests that anger may actually be linked with better, not worse, health in certain cultures.
"Many of us in Western societies naively believe that anger is bad for health, and beliefs like these appear to be bolstered by recent scientific findings," says psychological scientist Shinobu Kitayama of the University of Michigan. "But our study suggests that the truism linking anger to ill health may be valid only within the cultural boundary of the 'West,' where anger functions as an index of frustration, poverty, low status and everything else that potentially compromises health."
"These findings show how socio-cultural factors go under the skin to influence vital biological processes," explains Kitayama.
In other words, it's the circumstances that elicit anger, and not anger itself, that seem to be bad for health. In previous work, Kitayama and colleagues found that anger can function as a signal of high status and privilege in Asia -- drawing on this, they hypothesized that greater expression of anger might be associated with better health among Asian participants.
A recent incident on a Korean Air flight bound for Seoul illustrates this point, says Kitayama. Heather Cho, former vice president of Korean Air and daughter of Korean Air Chairman Cho Yang-ho, apparently flew into a rage when she was improperly served a bag of macadamia nuts by the chief flight attendant. In an angry outburst, Ms. Cho ordered the pilot to take the plane back to the gate so that the flight attendant could be kicked off the flight.
This expression of anger, which may seem disproportionate to the circumstance, is a typical display of privilege and power, says Kitayama, and may, therefore, be linked with better rather than worse health.
To explore the link, the researchers examined data from American participants drawn from the Midlife in the United States (MIDUS) survey and data from Japanese participants drawn from the Midlife in Japan (MIDJA) survey.
To measure health, the researchers looked at biomarkers for inflammation and cardiovascular functioning, both of which have been linked to anger expression in previous research. The combination of these two factors served as a measure of overall biological health risk.
The researchers also looked at measures that gauged various aspects of anger, including how often participants expressed angry feelings through verbally or physically aggressive behaviors (e.g., "I slam doors," "I say nasty things").
The data revealed that greater anger expression was associated with increased biological health risk among American participants, as previous studies have shown.
But greater anger expression was associated with reduced biological health risk among Japanese participants. And the association was not explained by other potentially related factors -- such as age, gender, chronic health conditions, smoking and alcohol consumption, social status, and experience of negative emotions more generally.
"The association between greater anger and compromised biological health, taken for granted in the current (Western) literature, was completely reversed so that greater anger was associated with better biological health among Japanese," explains Kitayama.
The researchers did not find a link between other facets of anger, such as chronic propensity toward anger or the extent to which participants suppressed feelings of anger, and health outcomes.
Together, these findings suggest that the link between anger expression and health reflects different experiences across cultural contexts. In the US, expressing anger seems to reflect the degree to which people experience negative events, while in Japan it may reflect the degree to which people feel empowered and entitled.
"Our point is that anger expression is a complex phenomenon likely motivated by a variety of factors, many of which could be culture-specific. These cultural factors must be taken into account to achieve a full understanding of the link between anger and health," the researchers write.
Kitayama and colleagues hope that future longitudinal research that follows participants over time will help to shed light on the relationship:
"Such research will help us address whether improving personal and social life styles so as to reduce anger may entail long-term health benefits."
http://www.sciencedaily.com/releases/2015/01/150107122916.htm
Chronic insomniacs may face increased risk of hypertension
January 26, 2015
Science Daily/American Heart Association
Insomniacs who take longer than 14 minutes to fall asleep face a greater risk of hypertension, according to new research. This study is the first to test whether insomnia with physiological hyperarousal, defined as a longer time to fall asleep, is linked to hypertension.
"We observed a strong correlation between the degree of physiological hyperarousal and hypertension," said Xiangdong Tang M.D., Ph.D, co- author of the study and professor of sleep medicine at West China Hospital, Sichuan University in Chengdu, China.
"In other words, those insomniacs who were hyperalert during the day and unable to relax and fall asleep during the Multiple Latency Sleep Test (MSLT) had the higher risk of hypertension," said study co-author Alexandros Vgontzas, M.D., professor of sleep research and treatment in the Department of Psychiatry at Pennsylvania State University College of Medicine in Hershey, Penn.
Insomnia is the most prevalent sleep disorder in the general population. One-fourth to one-third of the general population complains of difficulty falling asleep and about 10 percent have chronic complaints and seek medical help for insomnia.
Researchers studied 219 chronic insomniacs and 96 normal sleepers (average age 40 and more than 60 percent women). They defined chronic insomnia as difficulty sleeping for more than six months.
The participants spent one night monitored in a sleep lab and took the MLST the next day. Monitoring included four 20-minute nap opportunities at two-hour intervals: 9 a.m., 11 a.m., 1 p.m. and 3 p.m. Half the participants took 14 minutes or less to fall asleep and half took more than 14 minutes to fall asleep. Those that took more than 14 minutes to fall asleep were considered "hyperaroused."
Hypertension was based on blood pressure measures or a physician's diagnosis. Researchers controlled for confounding factors such as obesity, sleep apnea, diabetes, smoking, alcohol and caffeine use.
Chronic insomnia combined with an MSLT score greater than 14 minutes increased the odds of hypertension by 300 percent. MSLT scores greater than 17 minutes increased the odds by 400 percent.
"Long latency times to fall asleep during the day may be a reliable index of the physiological hyperarousal and biological severity of the disorder," Vgontzas said.
Traditionally, insomnia has been perceived as a nighttime sleep disorder; however, several studies suggest it's a state of 24-hour hyperarousal.
A more biologically severe type of insomnia is associated with 24-hour hyperarousal and significant cardiometabolic consequences like hypertension. The less severe form has primarily psychological roots.
Feeling hyperalert or sleepy doesn't allow people to function at their best, feel well during the day or sleep well at night, Vgontzas said.
"Although insomniacs complain of fatigue and tiredness during the day, their problem is that they cannot relax and that they are hyper," he said. "Measures that apply in sleep-deprived normal sleepers -- napping, caffeine use or other stimulants to combat fatigue -- do not apply in insomniacs. In fact, excessive caffeine worsens the hyperarousal."
http://www.sciencedaily.com/releases/2015/01/150126161759.htm
Sleep problems may impact bone health
February 3, 2015
Science Daily/Wiley
The daily rhythm of bone turnover is likely important for normal bone health, and recent research suggests that sleep apnea may be an unrecognized cause of some cases of osteoporosis. Sleep apnea's effects on sleep duration and quality, oxygen levels, inflammation, and other aspects of health may have a variety of impacts on bone metabolism, experts say.
It's important to determine the relationship between these two increasingly common diseases and to understand the biological processes that may connect them, experts note in a Journal of Bone and Mineral Research review.
"There are strong indications that daily rhythms are an intrinsic and important element of bone biology," said senior author Dr. Eric Orwoll. "If sleep disorders like obstructive sleep apnea affect bone metabolism, they may have diagnostic and therapeutic implications for many patients, including those affected by sleep apnea in their early, bone modeling years," added lead author Dr. Christine Swanson.
http://www.sciencedaily.com/releases/2015/02/150203104104.htm