Stressed to the max? Deep sleep can rewire the anxious brain
A sleepless night can trigger up to a 30 percent rise in emotional stress levels, new study shows
https://www.sciencedaily.com/images/2019/11/191104124140_1_540x360.jpg 11-8
Deep sleep concept (stock image). Credit: © stokkete / Adobe Stock
November 4, 2019
Science Daily/University of California - Berkeley
Researchers have found that the type of sleep most apt to calm and reset the anxious brain is deep sleep, also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronized, and heart rates and blood pressure drop.
When it comes to managing anxiety disorders, William Shakespeare's Macbeth had it right when he referred to sleep as the "balm of hurt minds." While a full night of slumber stabilizes emotions, a sleepless night can trigger up to a 30% rise in anxiety levels, according to new research from the University of California, Berkeley.
UC Berkeley researchers have found that the type of sleep most apt to calm and reset the anxious brain is deep sleep, also known as non-rapid eye movement (NREM) slow-wave sleep, a state in which neural oscillations become highly synchronized, and heart rates and blood pressure drop.
"We have identified a new function of deep sleep, one that decreases anxiety overnight by reorganizing connections in the brain," said study senior author Matthew Walker, a UC Berkeley professor of neuroscience and psychology. "Deep sleep seems to be a natural anxiolytic (anxiety inhibitor), so long as we get it each and every night."
The findings, published today, Nov. 4, in the journal Nature Human Behaviour, provide one of the strongest neural links between sleep and anxiety to date. They also point to sleep as a natural, non-pharmaceutical remedy for anxiety disorders, which have been diagnosed in some 40 million American adults and are rising among children and teens.
"Our study strongly suggests that insufficient sleep amplifies levels of anxiety and, conversely, that deep sleep helps reduce such stress," said study lead author Eti Ben Simon, a postdoctoral fellow in the Center for Human Sleep Science at UC Berkeley.
In a series of experiments using functional MRI and polysomnography, among other measures, Simon and fellow researchers scanned the brains of 18 young adults as they viewed emotionally stirring video clips after a full night of sleep, and again after a sleepless night. Anxiety levels were measured following each session via a questionnaire known as the state-trait anxiety inventory.
After a night of no sleep, brain scans showed a shutdown of the medial prefrontal cortex, which normally helps keep our anxiety in check, while the brain's deeper emotional centers were overactive.
"Without sleep, it's almost as if the brain is too heavy on the emotional accelerator pedal, without enough brake," Walker said.
After a full night of sleep, during which participants' brain waves were measured via electrodes placed on their heads, the results showed their anxiety levels declined significantly, especially for those who experienced more slow-wave NREM sleep.
"Deep sleep had restored the brain's prefrontal mechanism that regulates our emotions, lowering emotional and physiological reactivity and preventing the escalation of anxiety," Simon said.
Beyond gauging the sleep-anxiety connection in the 18 original study participants, the researchers replicated the results in a study of another 30 participants. Across all the participants, the results again showed that those who got more nighttime deep sleep experienced the lowest levels of anxiety the next day.
Moreover, in addition to the lab experiments, the researchers conducted an online study in which they tracked 280 people of all ages about how both their sleep and anxiety levels changed over four consecutive days.
The results showed that the amount and quality of sleep the participants got from one night to the next predicted how anxious they would feel the next day. Even subtle nightly changes in sleep affected their anxiety levels.
"People with anxiety disorders routinely report having disturbed sleep, but rarely is sleep improvement considered as a clinical recommendation for lowering anxiety," Simon said. "Our study not only establishes a causal connection between sleep and anxiety, but it identifies the kind of deep NREM sleep we need to calm the overanxious brain."
On a societal level, "the findings suggest that the decimation of sleep throughout most industrialized nations and the marked escalation in anxiety disorders in these same countries is perhaps not coincidental, but causally related," Walker said. "The best bridge between despair and hope is a good night of sleep."
https://www.sciencedaily.com/releases/2019/11/191104124140.htm
Daylight Saving Time has long-term effects on health
November 4, 2019
Science Daily/Vanderbilt University Medical Center
The annual transition to and from daylight saving time (DST) has clinical implications that last longer than the days where clocks "fall back" or "spring forward."
Over time, DST eliminates bright morning light that critically synchronizes biologic clocks, which can be associated with increased risk of heart attack and ischemic stroke, as well as other negative effects of partial sleep deprivation.
Average sleep duration shrinks by 15 to 20 minutes for adults during DST transitions, which may also increase the risk of fatal accidents.
"People think the one-hour transition is no big deal, that they can get over this in a day, but what they don't realize is their biological clock is out of sync," said Beth Ann Malow, MD, Burry Chair in Cognitive Childhood Development, and professor of Neurology and Pediatrics in the Sleep Disorders Division at Vanderbilt University Medical Center.
"It's not one hour twice a year. It's a misalignment of our biologic clocks for eight months of the year. When we talk about DST and the relationship to light, we are talking about profound impacts on the biological clock, which is a structure rooted in the brain. It impacts brain functions such as energy levels and alertness," she said.
Malow and colleagues published a JAMA Neurology commentary today recapping large epidemiological studies that advocate for ending the practice of setting clocks forward or back.
Some people may have more flexible circadian rhythms and adjust quickly while others are more sensitive. Malow, an expert on autism and sleep, said that the transition impacts some children with autism for weeks or months.
While the sleep and circadian communities believe returning to standard time may be more biologically appropriate, gaining political buy-in for a nationwide change remains a challenge. State legislation is "all over the map," with some states considering a return to standard time and others in favor of permanent DST. Tennessee has passed legislation supporting permanent DST, although such a change would require action from the U.S. Congress
https://www.sciencedaily.com/releases/2019/11/191104144133.htm
What drives circadian rhythms at the poles?
November 4, 2019
Science Daily/University of Würzburg
Circadian clocks coordinate the organism to the alternating cycles of day and night. Scientists have studied how these clocks work in polar regions where days or nights can last for weeks.
In temperate latitudes, the right timing is crucial for almost all living things: Plants sprout with the advent of spring, bees know the best times to visit flowers, people get tired in the evening and wake up again in the morning. The constant change between light and dark, day and night is the rhythm to which all living beings must adapt if they want to survive and reproduce. Circadian clocks help them achieve this by regulating the timekeeping mechanism in each organism and adjusting it to changes.
Publication in Current Biology
But what happens in environments where the day-and-night cycle no longer follows the typical 24-hour rhythm as in the polar regions, when twilight is directly followed by dawn or when the sun is low above the horizon only for a few hours each day? Scientists from the Department of Neurobiology and Genetics of the University of Würzburg have looked into these questions; Dr. Pamela Menegazzi was in charge of the study. The team has published its results in the latest issue of Current Biology.
"Circadian clocks with a periodicity of about 24 hours enable animals to adapt to the day-and-night cycles. However, if these clocks are too rigid, this could be a disadvantage when adapting to weakly rhythmic environments like the polar regions," Menegazzi describes the background of the new study. She explains that several high-latitude species that live in the far north or south are known to no longer adapt their activities to a 24-hour rhythm but have adopted an arrhythmic behaviour instead.
Two possible explanations
At the Department of Neurobiology and Genetics, it's all about the circadian clock of Drosophila, also known as the common fruit fly. The fly provides several advantages for scientists: Its genome is easily accessible for interventions and its brain is relatively simple in structure but the molecular principles are the same as in humans. What is more, only 150 neurons form the basis of the fly's circadian clock whose functions are well-known for the most part. Drosophila species are encountered all over the world. They even thrive at very high latitudes where they exhibit the typical arrhythmic activity pattern. They are also found in subarctic regions where they are capable of adjusting their evening activity to the sometimes very long period of twilight.
It has been unknown previously which molecular mechanisms in the flies' clock system are responsible for these regional adaptations. Two models were discussed: "The arrhythmicity could either be due to a loss of the molecular oscillation within the master clock or alternatively a missing link between this master clock and its subordinate structures could be responsible," says Pamela Menegazzi.
Comparing two fly species
To answer this question, Menegazzi and her team conducted what is probably the first comparative analysis across genera. In addition to Drosophila, the scientists studied Chymomyza, a genus of vinegar flies which diverged from Drosophila about five million years ago to successfully colonise both low and high latitudes. The scientists chose this approach to take a closer look at the evolutionary adaptations of the circadian clock which facilitate the life of animals in the Arctic and subarctic.
The result: "Both explanations are equally valid," says Menegazzi. At least the molecular biological findings of this study support this assumption. In Drosophila ezoana , for example, the loss of the molecular clock function in the master clock facilitated the adaptation to living at high latitudes. The result is the same in Chymomyza costata but due to a missing link between the master clock and its output. "This suggests that the ability to maintain behavioural rhythmicity has been lost more than once during the evolution of the Drosophilidae family," the scientist concludes.
Strong rhythms can be a disadvantage
In their study, the scientists examined an old concept of chronobiology which says that circadian clocks must have certain properties, namely a 24-hour rhythm, the ability to synchronise to external stimuli, and another property which scientists call "self-sustaining" which means the ability to intrinsically maintain a rhythm in the long run. "It is becoming increasingly apparent that many organisms that are no standard model organisms do not possess all these characteristics," Menegazzi says.
At the same time, the results support the long-held hypothesis that strong behavioural rhythms may be a disadvantage in weakly rhythmic environments such as the polar regions. Additionally, they help scientists understand how animals adapt to different ecological niches and which characteristics could be beneficial in extreme environments. The researchers believe that identifying the characteristics that could be necessary to successfully colonise high latitudes could become even more relevant in light of climate change.
https://www.sciencedaily.com/releases/2019/11/191104141656.htm
Narcissism can lower stress levels and reduce chances of depression
October 29, 2019
Science Daily/Queen's University Belfast
People who have grandiose narcissistic traits are more likely to be 'mentally tough', feel less stressed and are less vulnerable to depression, research led by Queen's University Belfast has found.
While narcissism may be viewed by many in society as a negative personality trait, Dr Kostas Papageorgiou, who is Director of the InteRRaCt Lab in the School of Psychology at Queen's, has revealed that it could also have benefits. He has published two papers on narcissism and psychopathology in Personality and Individual Differences and European Psychiatry.
Dr Papageorgiou explains: "Narcissism is part of the 'Dark Tetrad' of personality that also includes Machiavellianism, Psychopathy and Sadism. There are two main dimensions to narcissism -- grandiose and vulnerable. Vulnerable narcissists are likely to be more defensive and view the behaviour of others as hostile whereas grandiose narcissists usually have an over inflated sense of importance and a preoccupation with status and power."
He adds: "Individuals high on the spectrum of dark traits, such as narcissism, engage in risky behaviour, hold an unrealistic superior view of themselves, are overconfident, show little empathy for others, and have little shame or guilt.
"However, what this research has questioned is -- if narcissism, as an example of the dark tetrad, is indeed so socially toxic, why does it persist and why is it on the rise in modern societies?"
The papers include three independent studies each involving more than 700 adults in total and highlights some positive sides of narcissism, such as resilience against symptoms of psychopathology.
A key finding of the research was that grandiose narcissism can increase mental toughness and this can help to offset symptoms of depression. It also found that people who score high on grandiose narcissism have lower levels of perceived stress and are therefore less likely to view their life as stressful.
The research is a fresh approach to the study of personality and psychopathology, highlighting that there are some positives to be found in terms of potential societal impact.
Dr Papageorgiou comments: "The results from all the studies that we conducted show that grandiose narcissism correlates with very positive components of mental toughness, such as confidence and goal orientation, protecting against symptoms of depression and perceived stress.
"This research really helps to explain variation in symptoms of depression in society -- if a person is more mentally tough they are likely to embrace challenges head on, rather than viewing them as a hurdle.
Dr Papageorgiou says: "While of course not all dimensions of narcissism are good, certain aspects can lead to positive outcomes.
"This work promotes diversity and inclusiveness of people and ideas by advocating that dark traits, such as narcissism, should not be seen as either good or bad, but as products of evolution and expressions of human nature that may be beneficial or harmful depending on the context.
"This move forward may help to reduce the marginalisation of individuals that score higher than average on the dark traits. It could also facilitate the development of research-informed suggestions on how best to cultivate some manifestations of these traits, while discouraging others, for the collective good."
https://www.sciencedaily.com/releases/2019/10/191029080728.htm
Anti-inflammatory agents can effectively and safely curb major depressive symptoms
Effects even stronger when added to antidepressant treatment, pooled data analysis shows
October 28, 2019
Science Daily/BMJ
Anti-inflammatory agents, such as aspirin/paracetamol, statins, and antibiotics, can safely and effectively curb the symptoms of major depression, finds a pooled analysis of the available evidence, published online in the Journal of Neurology Neurosurgery & Psychiatry.
And the effects are even stronger when these agents are added on to standard antidepressant treatment, the results show.
Around a third of people who are clinically depressed don't respond well to current drug and talking therapies, and drug side effects are relatively common.
An emerging body of evidence suggests that inflammation contributes to the development of major depression, but the results of clinical trials using various anti-inflammatory agents to treat the condition have proved inconclusive.
The researchers therefore set out to review the available evidence and pool the data to see if anti-inflammatory agents work better than dummy (placebo) treatment either alone or when used as add-on therapy to standard antidepressant treatment.
Anti-inflammatory agents included: non-steroidal anti-inflammatory drugs (NSAIDs); omega 3 fatty acids; drugs that curb production of inflammatory chemicals (cytokine inhibitors); statins; steroids; antibiotics (minocyclines); a drug used to treat sleep disorders (modafinil); and N-acetyl cysteine, known as NAC, and used to loosen the excess phlegm of cystic fibrosis and COPD and also taken as an antioxidant supplement.
The researchers trawled research databases to find suitable studies published up to January 2019. They found 30 relevant randomised controlled trials, involving 1610 people, which reported changes in depression scales. They pooled the data from 26 of these studies.
The pooled data analysis suggested that anti-inflammatory agents were better than placebo and enhanced the effects of standard antidepressant treatment.
These agents were 52% more effective in reducing symptom severity, overall, and 79% more effective in eliminating symptoms than placebo, as measured by an average fall in depression scales of 55.
More detailed analysis indicated that NSAIDs, omega 3 fatty acids, statins, and minocyclines were the most effective at reducing major depressive symptoms compared with placebo.
And the effects were even greater when one or other of these agents was added to standard antidepressant treatment.
But anti inflammatory agents didn't seem to improve quality of life, although this might have been because of the small number of studies which looked at this aspect, say the researchers.
No major side effects were evident, although there were some gut symptoms among those taking statins and NACs, and the trials lasted only 4 to 12 weeks, so it wasn't possible to track side effects over the longer term.
The researchers also point out that not all studies tracked changes in depression scores over the entire study period. The depression scales used in the studies differed, and those involving statins and minocyclines included only small numbers of patients.
Nevertheless, they conclude: "The results of this systematic review suggest that anti-inflammatory agents play an antidepressant role in patients with major depressive disorder and are reasonably safe."
https://www.sciencedaily.com/releases/2019/10/191028213923.htm
New study points to another possible correlation between sleep and overall good health
Your gut microbiome and quality sleep are interconnected
October 28, 2019
Science Daily/Nova Southeastern University
As if you didn't already have enough to worry about to keep you up at night, a new study indicates that poor sleep can negatively affect your gut microbiome, which can, in turn, lead to additional health issues.
Great.
That's at the heart -- or gut -- of the study just published in PLoS ONE that involved several researchers from Nova Southeastern University (NSU.) They wanted to see just how much of a connection there is between what is going on in our insides and how that may impact the quality of sleep we experience.
"Given the strong gut-brain bidirectional communication they likely influence each other," said Jaime Tartar, Ph.D., a professor and research director in NSU's College of Psychology who was part of the research team. "Based on previous reports, we think that poor sleep probably exerts a strong negative effect on gut health/microbiome diversity."
What you may be asking yourself right now is: "what in the world is a gut microbiome?" Simply put -- it's all the microorganisms (bacteria, viruses, protozoa and fungi) and their genetic material found in your gastrointestinal (GI) tract. And yes, we all have these in our GI tract, but not all at the same levels (diversity.) As it turns out, it's this diversity that could be the key.
For this study, subjects wore what Tartar called an "Apple Watch on steroids" to bed, which monitored all sorts of vitals. This way the researchers could determine just how well a night's sleep the subjects got, and then they tested the subjects' gut microbiome. What they found was those who slept well had a more diverse -- or "better" -- gut microbiome.
Tartar said that gut microbiome diversity, or lack thereof, is associated with other health issues, such as Parkinson's disease and autoimmune diseases, as well as psychological health (anxiety and depression.) The more diverse someone's gut microbiome is, the likelihood is they will have better overall health.
"We know that sleep is pretty much the 'Swiss Army Knife of health," Tartar said. "Getting a good night's sleep can lead to improved health, and a lack of sleep can have detrimental effects. We've all seen the reports that show not getting proper sleep can lead to short term (stress, psychosocial issues) and long-term (cardiovascular disease, cancer) health problems. We know that the deepest stages of sleep is when the brain 'takes out the trash' since the brain and gut communicate with each other. Quality sleep impacts so many other facets of human health."
Tartar's area of research focuses on the mechanisms and consequences of acute and chronic stress in humans and the impact of normal sleep and sleep deprivation on emotion processing and physiological functioning.
So what determines someone's gut microbiome? According to Robert Smith, Ph.D., an associate professor and research scientist at Nova Southeastern University (NSU) Halmos College of Natural Sciences and Oceanography, who is also a member of the research team, there are a couple of factors that come into play.
One is genetics -- some people are predisposed at a genetic level to have a more diverse gut microbiome than their friends and neighbors. Another factor is drugs -- certain medications, including antibiotics, can have an impact on the diversity of your gut microbiome. He also said that your diet plays a factor as well.
Smith said that their team, which included colleagues from Middle Tennessee State University, examined the association between sleep, the immune system and measures of cognition and emotion. He said understanding how these parts of human physiology work may lead to a better understanding of the "two-way communication" between the person and their gut microbiome, and could lead to novel sleep intervention strategies.
"The preliminary results are promising, but there's still more to learn," Smith said. "But eventually people may be able to take steps to manipulate their gut microbiome in order to help them get a good night's sleep."
https://www.sciencedaily.com/releases/2019/10/191028164311.htm
Daily exposure to blue light may accelerate aging, even if it doesn't reach your eyes
Woman looking at blue light from at computer screen (stock image). Credit: © Alliance / Adobe Stock
October 17, 2019
Science Daily/Oregon State University
Prolonged exposure to blue light, such as that which emanates from your phone, computer and household fixtures, could be affecting your longevity, even if it's not shining in your eyes.
New research at Oregon State University suggests that the blue wavelengths produced by light-emitting diodes damage cells in the brain as well as retinas.
The study, published today in Aging and Mechanisms of Disease, involved a widely used organism, Drosophila melanogaster, the common fruit fly, an important model organism because of the cellular and developmental mechanisms it shares with other animals and humans.
Jaga Giebultowicz, a researcher in the OSU College of Science who studies biological clocks, led a research collaboration that examined how flies responded to daily 12-hour exposures to blue LED light -- similar to the prevalent blue wavelength in devices like phones and tablets -- and found that the light accelerated aging.
Flies subjected to daily cycles of 12 hours in light and 12 hours in darkness had shorter lives compared to flies kept in total darkness or those kept in light with the blue wavelengths filtered out. The flies exposed to blue light showed damage to their retinal cells and brain neurons and had impaired locomotion -- the flies' ability to climb the walls of their enclosures, a common behavior, was diminished.
Some of the flies in the experiment were mutants that do not develop eyes, and even those eyeless flies displayed brain damage and locomotion impairments, suggesting flies didn't have to see the light to be harmed by it.
"The fact that the light was accelerating aging in the flies was very surprising to us at first," said Giebultowicz, a professor of integrative biology. "We'd measured expression of some genes in old flies, and found that stress-response, protective genes were expressed if flies were kept in light. We hypothesized that light was regulating those genes. Then we started asking, what is it in the light that is harmful to them, and we looked at the spectrum of light. It was very clear cut that although light without blue slightly shortened their lifespan, just blue light alone shortened their lifespan very dramatically."
Natural light, Giebultowicz notes, is crucial for the body's circadian rhythm -- the 24-hour cycle of physiological processes such as brain wave activity, hormone production and cell regeneration that are important factors in feeding and sleeping patterns.
"But there is evidence suggesting that increased exposure to artificial light is a risk factor for sleep and circadian disorders," she said. "And with the prevalent use of LED lighting and device displays, humans are subjected to increasing amounts of light in the blue spectrum since commonly used LEDs emit a high fraction of blue light. But this technology, LED lighting, even in most developed countries, has not been used long enough to know its effects across the human lifespan."
Giebultowicz says that the flies, if given a choice, avoid blue light.
"We're going to test if the same signaling that causes them to escape blue light is involved in longevity," she said.
Eileen Chow, faculty research assistant in Giebultowicz's lab and co-first author of the study, notes that advances in technology and medicine could work together to address the damaging effects of light if this research eventually proves applicable to humans.
"Human lifespan has increased dramatically over the past century as we've found ways to treat diseases, and at the same time we have been spending more and more time with artificial light," she said. "As science looks for ways to help people be healthier as they live longer, designing a healthier spectrum of light might be a possibility, not just in terms of sleeping better but in terms of overall health."
In the meantime, there are a few things people can do to help themselves that don't involve sitting for hours in darkness, the researchers say. Eyeglasses with amber lenses will filter out the blue light and protect your retinas. And phones, laptops and other devices can be set to block blue emissions.
"In the future, there may be phones that auto-adjust their display based on the length of usage the phone perceives," said lead author Trevor Nash, a 2019 OSU Honors College graduate who was a first-year undergraduate when the research began. "That kind of phone might be difficult to make, but it would probably have a big impact on health."
https://www.sciencedaily.com/releases/2019/10/191017101253.htm
Twin study shows what's good for the heart is good for the brain
Relationship between CV risk and cognitive decline
October 21, 2019
Science Daily/Emory Health Sciences
Researchers are giving us double the reasons to pay attention to our cardiovascular health - showing in a recent study that good heart health can equal good brain health.
Emory University researchers are giving us double the reasons to pay attention to our cardiovascular health -- showing in a recently published study in the Journal of Alzheimer's Disease that good heart health can equal good brain health.
The American Heart Association defines ideal cardiovascular health (CVH) across seven modifiable risk factors (blood sugar, serum cholesterol, blood pressure, body mass index, physical activity, diet and cigarette smoking). Higher CVH scores point to better heart health and lower risk for cardiovascular disease (CVD).
Prior studies have indicated that ideal CVH also benefits brain health and cognitive aging. However, it was unclear how genes and/or environment played into the relationship between cardiovascular risk factors and cognitive decline.
By studying pairs of twin brothers from the Vietnam Era Twin (VET) registry, researchers were able to observe the relationship between CVH and cognitive performance across all participants that may be explained by genetics and/or exposures or behaviors that are shared by members of the same family.
Twin studies are a special type of epidemiological study that allow researchers to examine the overall role of genes and environment in a behavioral trait or disorder. Identical twins share 100 percent of their genetic material, while fraternal twins share on average 50 percent of genetic material. For a given trait or medical condition, any excess similarity between identical twins compared with fraternal twins, is likely suggestive of genes rather than environment. Twin studies can serve to differentiate between "nature vs. nurture."
"Our study across the entire sample of twins confirmed that better CVH is associated with better cognitive health in several domains," says senior author Viola Vaccarino, MD, PhD, Wilton Looney Professor of Cardiovascular Research, Rollins School of Public Health, and professor, division of cardiology, Emory University School of Medicine. "The analyses further suggested that familial factors shared by the twins explain a large part of the association and thus could be important for both cardiovascular and brain health."
To determine whether these familial factors were genetically or environmentally driven, researchers further stratified the within-pair analysis to determine whether the relationship between CVH and cognitive function was different between identical and fraternal twins.
The within-pair association was similar in identical and fraternal twins. Therefore familial factors, such as early family environment, early socioeconomic status and education, and parenting -- rather than genetics -- may be important precursors of both cardiovascular and brain health -- thus explaining some of the association between CVH and cognition.
"Improving population-level CVH scores, which are extremely low in the United States, has the potential to reduce the burden of dementia along with heart disease," says study co-author Ambar Kulshreshtha, MD, PhD, assistant professor of family and preventive medicine, Emory University School of Medicine. "Because CVH factors are modifiable, prevention of cardiovascular risk factors and promotion of a healthy lifestyle beginning early in life should achieve the best results for promoting not only cardiovascular health, but also cognitive health."
https://www.sciencedaily.com/releases/2019/10/191021135040.htm
Why bright light keeps us awake
October 15, 2019
Science Daily/Salk Institute
Researchers are reporting a novel technique for tracing the activity of individual nerve fibers known as axons, and determining how neurons communicate. The team used this technique to uncover details about how the brain responds to light signals received by the retina in mice.
In recent decades, scientists have learned a great deal about how different neurons connect and send signals to each other. But it's been difficult to trace the activity of individual nerve fibers known as axons, some of which can extend from the tip of the toe to the head. Understanding these connections is important for figuring out how the brain receives and responds to signals from other parts of the body.
Researchers at the Salk Institute and UC San Diego are reporting a novel technique for tracing these connections and determining how neurons communicate. The team used this technique to uncover details about how the brain responds to light signals received by the retina in mice, published October 15, 2019, in Cell Reports.
"This study is a breakthrough because no one could figure out how to study these connections before," says Salk Professor Satchidananda Panda, co-corresponding author of the paper. "This new technique has enabled us to go well beyond the limitations of electron microscopy."
The new method makes use of several different laboratory techniques to understand a type of neuron called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells, which are found in the retina, in the back of the eye, express a protein called melanopsin that senses blue light.
The Salk and UCSD teams used a virus to deliver a protein called a mini-singlet oxygen-generating protein (mini-SOG) to the ipRGCs, so that the cells could be viewed in more detail under election microscopy. The system was designed to tether the mini-SOG to the membranes of the light-sensitive cells so that the entire neuron, including its long axons that reach out to different parts of the brain, can be easily tracked under both light and electron microscope.
"Thanks to development and application of new genetically introduced probes for correlated multiscale light and electron microscopic imaging, our Salk and UCSD-based research teams were able to follow the small processes emanating from nerve cells over centimeters, all the way from the retina to multiple places where they connect to brain regions critical to circadian rhythms, eye reflexes and vision," says Mark Ellisman, distinguished professor of neurosciences at UC San Diego and adjunct professor at Salk, who co-led the work. "We were able to obtain unprecedented three-dimensional information about the machinery required for these neuronal cells to signal the next neurons in the complex circuits."
Most of the previous work with mini-SOGs has been done in cell lines, and using them in mice, to map how neurons from the retina wire the brain, was a first, according the researchers. The method enabled them to glean new information about the connections between ipRGCs and different parts of the brain.
The ipRGCs are known to connect to many brain regions that regulate very different tasks. The cells tell one part of the brain how bright it is outside so that our pupil can rapidly close -- in less than a second. The same ipRGCs also connect to the master clock in the brain that regulates our sleep-wake cycle. "However, it takes several minutes of bright light to make us fully awake," Panda says. "How the same ipRGCs do these very different tasks with different time scales was not clear until now."
The investigators found that the difference has to do with the way that light detected by the retina reaches the brain. By delivering the mini-SOG to the eyes of the mice, they were able to trace the signal to the part of the brain that constricts the pupil in response to light.
"These connections were much stronger -- similar to water pouring out of a garden hose," Panda says. "Whereas the connection between the ipRGCs and the master clocks were weaker -- more like drip irrigation." Because the ipRGCs deliver the light signal to the circadian center through this slower drip system, it takes longer for any meaningful information to reach and reset the brain clock.
"This research helps explain why, when you get up in the night to get a drink of water and turn on the light for a few seconds, you're usually able to go right back to sleep," Panda says. "But if you hear a noise outside and end up walking around your house for half an hour with the lights on, it's much harder. There will be enough light signal reaching the master clock neurons in the brain that ultimately wakes up the rest of the brain."
Panda says that the new technique will be useful for studying other neural connections, as the researchers can essentially use the same viruses to express mini-SOGs in any neuron and ask how different neurons make connections to different appendages.
"These findings and methods open new opportunities for brain researchers studying the long-distance wiring of brains in normal and in animal models of human disease," adds Ellisman.
https://www.sciencedaily.com/releases/2019/10/191015131508.htm
A timekeeper for siesta
October 7, 2019
Science Daily/University of Würzburg
External stimuli can rearrange the hierarchy of neuronal networks and influence behavior. This was demonstrated by scientists using the circadian clock of the fruit fly as an example.
Circadian clocks must be flexible and they must be able to adapt to varying environmental conditions. Otherwise, it would be impossible for living beings to change their patterns of activity when the days get shorter again as is happening now. After all, Drosophila, also known as the common fruit fly, no longer needs a long siesta in autumn to protect itself from excessive heat and predators as in the middle of summer, at least in our latitudes. At the same time, the fly must shift its evening activity peak a few hours forward if it doesn't want to end up buzzing around in the dark.
For the fruit fly to adapt to changing day-and-night rhythms, its circadian clock must be able to process external cues, so-called zeitgebers, which are used to synchronise the molecular and physiological properties of the organism. Light is the most important zeitgeber the fly uses for this.
Publication in Current Biology
Scientists from the Department of Neurobiology and Genetics at the University of Würzburg have been researching the interaction of light, photoreceptors and circadian clocks in the fruit fly for some time. Chair holder, Charlotte Förster, together with her former colleague Matthias Schlichting, who presently works at Brandeis University (Massachusetts, USA), have now figured out new and surprising details of this interaction. They present the results of their research in the current issue of Current Biology.
"In mammals, a combination of the traditional photoreceptor pathway (rods and cones of the retina) and the circadian photoreceptor melanopsin in retinal ganglion cells enables the fine-tuning of clock synchronisation," Charlotte Förster explains. She says that there is a comparable mechanism in Drosophila: "The compound eyes, the extraretinal Hofbauer-Buchner eyelets and the circadian photoreceptor cryptochrome all work together in the light synchronisation process," the professor summarises the central result of the recently published study.
It is known from earlier studies how the photoreceptor cryptochrome works. Located in special nerve cells, the so-called clock neurons, it interacts with the timeless clock protein during light exposure, leading to the degradation of the protein. Figuratively speaking, it turns the clock back to zero. However, less is known about the exchange between the eyes of the fruit fly and the clock neurons and how the different day length is mediated.
Experiments with different day lengths
For their study, the scientists worked with different specimens of fruit flies. They used healthy flies, eyeless flies and flies lacking specific visual pigments of the eye, the so-called rhodopsins. During the laboratory experiments, the insects were exposed to different light conditions: At a constant day length of 24 hours, the researchers extended the period of light in two-hour increments from twelve to a maximum of 20 hours and observed the activity patterns of the respective fly groups.
It turned out that the activity of the insects changed with increasing length of the daylight period. When periods of light and darkness alternate regularly every twelve hours, which corresponds to a typical day at the equator, healthy flies become active twice: around the time of "sunrise" and before the simulated "sunset." As the days get longer, the evening activity is also delayed and the "siesta" -- the midday resting period -- is extended. It is striking though that as the periods of daylight increase, the activity peak in the evening deviates from the simulated sunset and is much earlier in some cases. The largest deviation occurs when the daylight period is 20 hours long, probably because the flies are never confronted with such conditions in their natural environment.
Discovery in the compound eye
While searching for the molecular and neuronal mechanisms which the fruit fly uses to "fine-tune" its circadian clock in a manner of speaking, the neurobiologists had to carry out numerous experiments. Experiments on fruit flies that lacked these eyes demonstrated that the compound eyes play a key role. Their activity peak was also delayed as the length of the daylight period increased, but much less so than in their seeing relatives. More experiments were conducted to pinpoint which receptor cell and visual pigment are responsible for this. After all, each facet of the fly's compound eye has eight receptor cells and five rhodopsins. So the scientists selectively switched off the individual cells until it was clear that receptor cell 8 and rhodopsins 5 and 6 which occur there were their targets.
The scientists next investigated how the light signal reaches the brain of the fruit fly and how it travels from there to the clock neurons. Surprisingly, they found that while the signal is transported via so-called "small lateral clock neurons" during "moderate" light periods, it travels through "large lateral clock neurons" in the 20-hour light experiments. "Although the circadian clock of the fruit fly is comparatively small with just 150 neurons, the overall system has high plasticity," Charlotte Förster recapitulates the results of the study and she explains that this neuronal plasticity is necessary to enable the animals to quickly adjust to varying conditions.
https://www.sciencedaily.com/releases/2019/10/191007103615.htm
Exposure to air pollution increases violent crime rates
October 3, 2019
Science Daily/Colorado State University
Breathing dirty air can make you sick. But according to new research, it can also make you more aggressive.
That's the conclusion from a set of studies recently authored by Colorado State University researchers in economics, atmospheric science and statistics. Together, the team found strong links between short-term exposure to air pollution and aggressive behavior, in the form of aggravated assaults and other violent crimes across the continental United States.
The results, derived from daily Federal Bureau of Investigation crime statistics and an eight-year, detailed map of daily U.S. air pollution, will be published in a forthcoming edition of the Journal of Environmental Economics and Management.
The paper's lead author is Jesse Burkhardt, assistant professor in the Department of Agricultural and Resource Economics, who teamed up with fellow economist Jude Bayham in the same department; Ander Wilson in the Department of Statistics; and several air pollution experts in civil engineering and atmospheric science.
The CSU researchers cross-analyzed three highly detailed datasets: daily criminal activity from the National Incident-Based Reporting System managed by the FBI; daily, county-level air pollution from 2006-2013 collected by U.S. Environmental Protection Agency monitors; and daily data on wildfire smoke plumes from satellite imagery provided by the National Oceanic and Atmospheric Administration's Hazard Mapping System.
Air pollution scientists typically measure rates of pollution through concentrations of ozone, as well as of "PM2.5," or breathable particulate matter 2.5 microns in diameter or smaller, which has documented associations with health effects.
Eighty-three percent of crimes considered "violent" by the FBI are categorized as assaults in crime databases. In the researchers' study, they observed whether crimes occurred inside or outside the home; they found that 56 percent of violent crimes and 60 percent of assaults occurred within the home, which is an indication that many such crimes are tied to domestic violence.
The research results show a 10 microgram-per-cubic-meter increase in same-day exposure to PM2.5 is associated with a 1.4% increase in violent crimes, nearly all of which is driven by crimes categorized as assaults. Researchers also found that a 0.01 parts-per-million increase in same-day exposure to ozone is associated with a 0.97% increase in violent crime, or a 1.15% increase in assaults. Changes in these air pollution measures had no statistically significant effect on any other category of crime.
"We're talking about crimes that might not even be physical -- you can assault someone verbally," co-author Bayham said. "The story is, when you're exposed to more pollution, you become marginally more aggressive, so those altercations -- some things that may not have escalated -- do escalate."
The researchers made no claims on the physiological, mechanistic relationship of how exposure to pollution leads someone to become more aggressive; their results only show a strong correlative relationship between such crimes and levels of air pollution.
The researchers were careful to correct for other possible explanations, including weather, heat waves, precipitation, or more general, county-specific confounding factors.
The team published a companion paper in the Journal of Environmental Economics and Policy with similar results that used monthly crime statistics. A third paper in Epidemiology, with lead author Jesse Berman at University of Minnesota and co-authors from CSU, used EPA pollution monitor databases and different statistical techniques and came to similar conclusions.
The tool that allowed the team to overlay crime data with pollution data was originally used in collaboration with CSU epidemiologist Sheryl Magazmen to study health effects from air pollution, explained co-author Jeff Pierce, associate professor in the Department of Atmospheric Science and a Monfort Professor. Pierce, associate professor Emily Fischer and researchers Kate O'Dell and Bonne Ford, had previously worked with Magzamen to detail how smoke and particulate matter exposure correlated with things like hospitalizations and asthma inhaler refills.
Burkhardt had been wanting to study whether breathing smoke could enact behavioral change when he met atmopsheric scientist Pierce.
"Several years ago, Fort Collins experienced a fairly severe wildfire season," Burkhardt said. "The smoke was so bad that after a few days, I started to get frustrated, and I wondered if frustration and aggression would show up in aggregate crime data."
Pierce recognized that the pollution-concentration product he and colleagues had designed, which provided detailed concentrations of total particulate matter and the fraction from smoke, would be useful for Burkhardt's desired application.
"The results are fascinating, and also scary," Pierce said. "When you have more air pollution, this specific type of crime, domestic violent crime in particular, increases quite significantly."
The economists calculated that a 10 percent reduction in daily PM2.5 could save $1.1 million in crime costs per year, which they called a "previously overlooked cost associated with pollution."
The authors remain interested in the relationships between pollution and cognitive outcomes, Burkhardt said. They are now working with a large online chess platform to determine if increased pollution exposure is correlated with worse chess performance.
The results are just one outcome of CSU's philosophy around "cluster hiring" faculty from disparate fields to study interdisciplinary problems. In this case, several of the researchers came to CSU under the Partnership for Air Quality, Climate and Health initiative launched several years ago by the Office of the Vice President for Research.
https://www.sciencedaily.com/releases/2019/10/191003114007.htm
Sleeping less than 6 hours and heart disease, stroke -- deadly combo
October 2, 2019
Science Daily/American Heart Association
Middle-aged adults with high blood pressure, Type 2 diabetes, heart disease or stroke could be at high risk for cancer and early death when sleeping less than six hours per day, according to new research published in the Journal of the American Heart Association, the open access journal of the American Heart Association.
"Our study suggests that achieving normal sleep may be protective for some people with these health conditions and risks," said lead study author Julio Fernandez-Mendoza, Ph.D., associate professor at Pennsylvania State College of Medicine and sleep psychologist at the Sleep Research & Treatment Center of the Penn State Health Milton S. Hershey Medical Center in Hershey, Pennsylvania. "However, further research is needed to examine whether improving and increasing sleep through medical or behavioral therapies can reduce risk of early death."
Researchers analyzed data of more than 1,600 adults (20 to 74 years old, more than half women) from the Penn State Adult Cohort who were categorized into two groups as having stage 2 high blood pressure or Type 2 diabetes and having heart disease or stroke. Participants were studied in the sleep laboratory (1991-1998) for one night and then researchers tracked their cause of death up to the end of 2016.
Researchers found:
· Of the 512 people who passed away, one-third died of heart disease or stroke and one-fourth died due to cancer.
· People who had high blood pressure or diabetes and slept less than 6 hours had twice the increased risk of dying from heart disease or stroke.
· People who had heart disease or stroke and slept less than 6 hours had three times the increased risk of dying from cancer.
· The increased risk of early death for people with high blood pressure or diabetes was negligible if they slept for more than 6 hours.
"Short sleep duration should be included as a useful risk factor to predict the long-term outcomes of people with these health conditions and as a target of primary and specialized clinical practices," Fernandez-Mendoza said. "I'd like to see policy changes so that sleep consultations and sleep studies become a more integral part of our healthcare systems. Better identification of people with specific sleep issues would potentially lead to improved prevention, more complete treatment approaches, better long-term outcomes and less healthcare usage."
Sleep duration in this study was based on observing one night's sleep, which may be affected by the first-night effect where participants sleep significantly worse the first night in a lab compared to other consecutive nights, which is the type of sleep study routinely used in clinical practices.
According to the American Heart Association, roughly 45% of the United States population has stage 2 high blood pressure and/or Type 2 diabetes, while another 14% have heart disease or stroke.
https://www.sciencedaily.com/releases/2019/10/191002075944.htm
Coastal living linked with better mental health
Living close to the sea could support better mental health
September 30, 2019
Science Daily/University of Exeter
Researchers used survey data from nearly 26,000 respondents in their analysis, which marks one of the most detailed investigations ever into the well-being effects of being beside the sea. After taking other related factors into account, the study revealed that living in large towns and cities near to England's coastline is linked with better mental health for those in the lowest earning households.
Living close to the sea could support better mental health in England's poorest urban communities, finds a new study published today in the journal Health and Place.
Researchers from the University of Exeter used survey data from nearly 26,000 respondents in their analysis, which marks one of the most detailed investigations ever into the wellbeing effects of being beside the sea.
After taking other related factors into account, the study revealed that living in large towns and cities near to England's coastline is linked with better mental health for those in the lowest earning households.
Approximately one in six adults in England suffer from mental health disorders such as anxiety and depression, and these are far more likely in people from poorer backgrounds. The findings suggest that access to the coast could help to reduce these health inequalities in towns and cities close to the sea.
The research used data from the Health Survey for England and compared people's health to their proximity to the coast; from those living less than 1km away, to those more than 50km away. Its findings add to the growing evidence that access to blue spaces -- particularly coastal environments -- might improve health and wellbeing.
Dr Jo Garrett led the study and believes the results could have important implications, she said: "Our research suggests, for the first time, that people in poorer households living close to the coast experience fewer symptoms of mental health disorders. When it comes to mental health, this 'protective' zone could play a useful role in helping to level the playing field between those on high and low income."
The report represents the first time the benefits of coastal living have been demonstrated at such a detailed level according to income, and comes as Natural England prepares to open access to all of England's Coast Path by 2020. With everywhere in England within 70 miles of the sea, more people could harness the wellbeing benefits of living near to the coast thanks to improved access.
Dr Mathew White, environmental psychologist at the University of Exeter, said: "This kind of research into blue health is vital to convincing governments to protect, create and encourage the use of coastal spaces. We need to help policy makers understand how to maximise the wellbeing benefits of 'blue' spaces in towns and cities and ensure that access is fair and inclusive for everyone, while not damaging our fragile coastal environments."
https://www.sciencedaily.com/releases/2019/09/190930214514.htm
People with anxiety may strategically choose worrying over relaxing
September 30, 2019
Science Daily/Penn State
Relaxing is supposed to be good for the body and soul, but people with anxiety may actively resist relaxation and continue worrying to avoid a large jump in anxiety if something bad does happen, according to Penn State research.
In a new study, the researchers found that people who were more sensitive to shifts in negative emotion -- quickly moving from a relaxed state to one of fear, for example -- were more likely to feel anxious while being led through relaxation exercises.
Michelle Newman, professor of psychology, said the results could help benefit people who experience "relaxation-induced anxiety," a phenomenon that occurs when people actually become more anxious during relaxation training.
"People may be staying anxious to prevent a large shift in anxiety, but it's actually healthier to let yourself experience those shifts," Newman said. "The more you do it, the more you realize you can do it and it's better to allow yourself to be relaxed at times. Mindfulness training and other interventions can help people let go and live in the moment."
Hanjoo Kim, a graduate student in psychology, said the study also sheds light on why relaxation treatments designed to help people feel better can potentially cause more anxiety.
"People who are more vulnerable to relaxation-induced anxiety are often the ones with anxiety disorders who may need relaxation more than others," Kim said. "And of course, these relaxation techniques were meant to help, not make someone more anxious. Our findings will hopefully serve as a cornerstone for providing better care for these populations."
Newman said that while researchers have known about relaxation-induced anxiety since the 1980s, the specific cause of this phenomenon has remained unknown. When Newman developed the contrast avoidance theory in 2011, she thought the two concepts might be connected.
"The theory revolves around the idea that people may make themselves anxious intentionally as a way to avoid the letdown they might get if something bad were to happen," Newman said. "This isn't actually helpful and just makes you more miserable. But, because most of the things we worry about don't end up happening, what's reinforced in the brain is, 'I worried and it didn't happen so I should continue worrying.'"
For this study, the researchers recruited 96 college students. Participants included 32 people with generalized anxiety disorder, 34 people with major depressive disorder and 30 controls with neither disorder.
When the participants arrived at the lab, the researchers led them through relaxation exercises before having them watch videos that may elicit fear or sadness. The participants then answered a list of questions designed to measure how sensitive they were to changes in their emotional state. For example, some people may be uncomfortable with the negative emotions incited by the videos right after relaxing, while others might find the relaxation session helpful in dealing with those emotions.
Next, the researchers led the participants through a relaxation session once more before having them fill out a second survey. These questions were designed to measure the participants' anxiety during the second relaxation session.
After analyzing the data, the researchers found that people with generalized anxiety disorder were more likely to be sensitive to sharp spikes in emotion, like going from feeling relaxed to feeling scared or stressed. Additionally, this sensitivity was linked to feeling anxious during sessions intended to induce relaxation.
The researchers found similar results in people with major depressive disorder, although the effect wasn't as strong.
Kim said he hopes the results -- recently published in the Journal of Affective Disorders -- may help clinicians provide better care for people with anxiety.
"Measuring relaxation-induced anxiety and implementing exposure techniques targeting the desensitization of negative contrast sensitivity may help patients reduce this anxiety," Kim said. "Also, it would be important to examine relaxation-induced anxiety in other disorders, such as panic disorder and persistent mild depression."
https://www.sciencedaily.com/releases/2019/09/190930114737.htm
Sleep varies by age, geographical location and gender
September 27, 2019
Science Daily/University of Helsinki
In an exceptionally extensive worldwide study on sleep, nearly a quarter of a million nights of sleep were measured among sleepers ranging between 16 and 30 years of age.
The findings indicate that there are differences in the duration and timing of sleep by age, geographical region and gender. The timing of sleep was delayed among 16-24-year-old subjects, but in older subjects sleep was again timed earlier.
"It was interesting to find that the circadian rhythm shifts later even in people over 20 years of age. It was already previously known that sleep timing is delayed in adolescence. What was clearly highlighted in this study is how long into adulthood this actually carries on," says Liisa Kuula, a postdoctoral researcher at the University of Helsinki.
People in Europe and North America slept the longest, while the shortest sleep was observed in Asian countries. Sleep was timed the latest in the Middle East, while the earliest sleep rhythm was found in Oceania.
Young women slept more than young men, and the former also went to sleep earlier.
"Geographical differences were relatively small but similar to those seen in prior, smaller-scale studies. The need for sleep does not vary greatly between cultures, but differences arise in terms of the time reserved for sleeping," Kuula notes.
In the study, published in the Sleep Medicine journal, the sleeping habits of more than 17,000 adolescents and young adults were monitored for two weeks. The monitoring was carried out with the help of Polar Electro devices worn by the study subjects, measuring sleep with accelerometers, among other technologies. The subjects gave consent for using their personal data for research purposes, with the data being processed in anonymised form.
"We gained an exceptionally diverse and extensive dataset which provides important basic knowledge on sleep among different age groups across the globe. Validated consumer devices may hold the potential for investigations more comprehensive than those conducted with conventional data collection methods," Kuula says.
https://www.sciencedaily.com/releases/2019/09/190927102454.htm
Link between stress and circadian clock health
September 26, 2019
Science Daily/University of Minnesota Medical School
The human body has an internal biological clock that is constantly running. Our well-being is dependent on the function of that clock. New research from the University of Minnesota Medical School found a little stress can make the circadian clock run better and faster.
Research in the past several decades has found that our body has evolved a set of machinery, called the circadian clock, that internally drives rhythms in almost every cell. The activities of the circadian clock are influenced by various signals in the cells.
In a recent study published in Neuron, Ruifeng Cao, MD, PhD, Assistant Professor in the Department of Biomedical Sciences at the Medical School, and a team of seven laboratories in the U.S. and Canada focused on the crosstalk between cellular stress signals and the circadian clock.
Cells respond to various stress signals by activating a signal transduction cascade that is centered on the protein eIF2α, which is a pivotal factor that orchestrates protein synthesis in cells. Cao and his team found that in one's central brain clock, stress leads to rhythmic phosphorylation of eIF2α, which promotes production of the ATF4 protein. The ATF4 protein activates the Per2 gene, which ultimately makes the clock tick faster. They concluded that this mechanism is necessary to maintain a robust clock, and therefore, that stress signals influence the speed and robustness of the circadian clock.
It has been known that the circadian clock gets broken in many diseases, but the reason for it has been unclear. Cao's finding may provide insight into this unanswered question, as it is the first connection between two fundamental processes in cells: stress response and circadian timekeeping. One explanation could be that stress responses frequently go awry in diseased conditions, which may, in turn, mess up the clock.
"The next step is a more thorough and larger scale study on the crosstalk between the cellular stress network and the circadian clock," said Cao. "Hopefully our work can lead to discovering medicine that can manage the stress level and regulate the clock function in disease to keep people healthier."
https://www.sciencedaily.com/releases/2019/09/190926134452.htm
Positive relationships boost self-esteem, and vice versa
Robust reciprocal link found across life span
September 26, 2019
Science Daily/American Psychological Association
Does having close friends boost your self-esteem, or does having high self-esteem influence the quality of your friendships?
Both, according to a meta-analysis of more than two decades of research, published by the American Psychological Association.
"For the first time, we have a systematic answer to a key question in the field of self-esteem research: Whether and to what extent a person's social relationships influence his or her self-esteem development, and vice versa, and at what ages," said study author Michelle A. Harris, PhD, of The University of Texas at Austin. "The answer to what age groups is across the life span."
The research was published in the Journal of Personality and Social Psychology.
Harris and her co-author, Ulrich Orth, PhD, of the University of Bern, analyzed 52 studies involving more than 47,000 participants (54% female) looking at either the effect of self-esteem on social relationships over time or the reverse effect. The studies, all published between 1992 and 2016, included multiple countries (e.g., 30 samples from the United States, four from Switzerland, three from Germany, two each from Australia, Belgium, Canada, Finland, Greece, Russia and Sweden). Participants were 60% white, 2% Hispanic/Latino, 12% other predominantly another ethnicity and 19% mixed ethnicities. Samples ranged from early childhood to late adulthood.
The authors found that positive social relationships, social support and social acceptance help shape the development of self-esteem in people over time across ages 4 to 76. The authors also found a significant effect in the reverse direction. While earlier research had yielded inconsistent findings, the meta-analysis supports the classic and contemporary theories of the influence of self-esteem on social connections and the influence of social connections on self-esteem, according to Harris. The findings were the same after accounting for gender and ethnicity.
"The reciprocal link between self-esteem and social relationships implies that the effects of a positive feedback loop accumulate over time and could be substantial as people go through life," according to Harris.
The authors discuss the idea that positive relationships with parents may cultivate self-esteem in children, which leads to more positive relationships with peers in adolescence, which may further strengthen the self-esteem of emerging adults, and so on into late adulthood. However, the field is still in need of an integrated theory that can explain whether relationships have such a cumulative effect across life, or whether certain relationships become particularly important at certain ages.
When self-esteem or quality of social relationships is low, Harris noted, it can negatively affect the other factor, and set off a downward spiral, making clinical interventions especially important to offset this potentially adverse development.
"The fact that the effect did not differ significantly among studies with different sample characteristics strengthens confidence in the robustness of our findings," said Harris.
"We found a limited number of longitudinal studies on self-esteem and specific relationships in adulthood as well as studies using measures other than self-report, so our findings only begin to speak to these groups, and we look forward to future work oriented towards filling these gaps."
https://www.sciencedaily.com/releases/2019/09/190926092416.htm
Stressed out: Americans making themselves sick over politics
One in five report lost sleep, damaged friendships
September 26, 2019
Science Daily/University of Nebraska-Lincoln
Nearly 40% of Americans surveyed for a new study said politics is stressing them out, and 4% -- the equivalent of 10 million US adults -- reported suicidal thoughts related to politics.
Never-ending campaigns, social media, 24-hour news cycles. Politics are impossible to escape, even for the casual observer.
But are policy fights and polarization more than a headache in the collective consciousness? New research from the University of Nebraska-Lincoln suggests yes -- that we're making ourselves sick over politics.
Nearly 40% of Americans surveyed for the study said politics is stressing them out, and one in five are losing sleep. These responses and others show many in the United States believe their mental and physical health has been harmed in some way by exposure to politics.
The research, led by Nebraska political scientist Kevin Smith, is the first to look comprehensively at the physical and emotional costs of paying attention to and participating in political discourse. Previous examinations have focused almost solely on economic costs, such as time lost from work to vote or the monetary costs of supporting a campaign.
Smith and co-authors John Hibbing, Foundation Regent University Professor of political science at Nebraska, and Matthew Hibbing of the University of California, Merced thought it was time for a different take.
"It became apparent, especially during the 2016 electoral season, that this was a polarized nation, and it was getting even more politically polarized," Smith, Olson Chair and professor of political science at Nebraska, said. "The cost of that polarization to individuals had not fully been accounted for by social scientists or, indeed, health researchers."
Smith said the results, which were published Sept. 25 in the journal PLOS ONE, are akin to a public health crisis.
"Quite a few of the numbers jumped out at me," Smith said. "Twenty percent have damaged friendships because of political disagreements. One in five report fatigue. And it's a small (proportion), but 4% of the people in our sample said they've had suicidal thoughts because of politics. That translates into 10 million adults."
Data were collected by YouGov for five days in March 2017, with 800 respondents. YouGov uses a panel of 1.8 million people to create representative samples. Because no previous studies on this phenomenon have been completed, the questionnaire was developed by mirroring diagnostic instruments used by Alcoholics Anonymous and Gamblers Anonymous. The survey contained 32 questions in four categories -- physical health, mental health, regretted behavior and social/lifestyle costs -- and delved into how people perceive politics as the source of the problems they were experiencing.
Among the other findings:
· 11.5% reported politics had adversely affected their physical health
· 31.8% said exposure to media outlets promoting views contrary to personal beliefs had driven them crazy
· 29.3% said they've lost their temper as a result of politics
· 1 in 5 say differences in political views have damaged a friendship
· 22.1% admit they care too much about who wins and who loses
"Politics is really negatively affecting a lot of people's lives, or at least, they're perceiving that politics is really negatively affecting their lives in deep and meaningful ways," Smith said.
"Stress is a real phenomenon that can have disastrous health effects. If politics is a significant contributor to the levels of stress that American adults are experiencing, then yeah, it makes sense that there's a real add-on health effect from that.
"If we understand what's causing it, that can lead us to ameliorative strategies."
Perceptions of political stress emerged more in respondents who considered themselves on the left side of the political spectrum. Smith said this may be tied to the controversial 2016 election cycle.
"One of the things that we're really interested in is: What happens if a very left-leaning person is elected into the White House?" Smith said. "Do the symptoms stay the same but shift across the ideological spectrum?"
Because the study is the first of its kind, Smith and his co-authors plan to re-issue the survey in the future and are assisting scholars in pursuing similar research.
"I think it's critically important that we push this out to other political scientists," Smith said. "We've already handed it over to a couple of psychologists to include on some of the surveys they're doing, so we will start to get a little clearer picture and a little bit more traction on some of the questions we have."
https://www.sciencedaily.com/releases/2019/09/190926073348.htm
Biological clock influences immune response efficiency
September 24, 2019
Science Daily/McGill University
The biological clock influences immune response efficacy. Indeed, CD8 T cells, which are essential to fight infections and cancers, function very differently according to the time of day.
According to a recent study published in Proceedings of the National Academy of Sciences, the biological clock influences immune response efficacy. Indeed, CD8 T cells, which are essential to fight infections and cancers, function very differently according to the time of day. The study was carried out by a team of researchers led by Nicolas Cermakian, PhD, of the Douglas Research Centre, and Nathalie Labrecque, PhD, of the Maisonneuve-Rosemont Hospital Research Centre.
We know that circadian rhythms are generated by "clock genes," which influence most organs and cells -- including those of the immune system, whose function varies according to the time of day. Accordingly, circadian rhythms are found for various aspects of physiology, including sleep, nutrition, hormonal activity, and body temperature. These daily rhythms help the body adapt to cyclical changes in the environment, such as seasons and the day and night cycle.
In earlier research, the team had demonstrated that T cells react more or less strongly to a foreign body according to the time of day, but the role of the biological clock in this phenomenon remained unknown. "Using a mouse vaccine model, we observed that after vaccination, the strength of the CD8 T cell response varied according to the time of day. Conversely, in mice whose CD8 T cells were deficient for the clock gene, this circadian rhythm was abolished, and response to the vaccine was diminished in the daytime," explains Dr. Cermakian, who is also Professor at the McGill University Department of Psychiatry.
"Our study shows that T cells are more prone to be activated at certain times of the day. Identifying the mechanisms through which the biological clock modulates the T cell response will help us better understand the processes that regulate optimal T cell responses. This knowledge will contribute to improving vaccination strategies and cancer immune therapies," states Nathalie Labrecque, Professor at the Departments of Medicine and Microbiology, Infectious Diseases and Immunology at Université de Montréal.
https://www.sciencedaily.com/releases/2019/09/190924125015.htm
New target regulating mitochondria during stress
Discovery could lead to new approach to treating heart failure, heart attack, stroke and neurodegeneration
September 19, 2019
Science Daily/Temple University Health System
Like an emergency response team that is called into action to save lives, stress response proteins in the heart are activated during a heart attack to help prevent cell death. As part of this process, Lewis Katz School of Medicine at Temple University researchers show for the first time that one of these specialized emergency responder proteins, known as MCUB, temporarily decreases harmful levels of calcium transport into mitochondria, the energy-generating batteries of cells.
The new research, published online September 19 in the journal Circulation, identifies MCUB as a promising new target for the investigation and treatment of conditions that feature calcium overload and cell death -- conditions that include heart failure, heart attack, stroke, and neurodegeneration.
"MCUB fine-tunes calcium uptake by mitochondria in injured heart tissue, in an attempt to limit calcium overload, which is a major contributor to cell death, particularly following a heart attack," explained John W. Elrod, PhD, Associate Professor in the Center for Translational Medicine at the Temple University Lewis Katz School of Medicine and senior investigator on the new study.
Calcium homeostasis is vital to a number of day-to-day cellular activities and is regulated primarily by mitochondria. For calcium to enter mitochondria, it passes through a channel known as the mitochondrial calcium uniporter (MCU), which resides in the inner mitochondrial membrane where it stimulates the production of ATP, the energy currency of the cell. The amount of calcium that mitochondria take up is regulated by various components of this channel. While MCUB closely resembles the pore forming subunit, MCU, its precise role in calcium regulation is largely unknown, particularly in the context of disease.
Dr. Elrod's team found that deletion of the MCUB gene in cells results in a change in the proteins that make up the calcium channel and that are essential for controlling whether the channel is on or off. Since these alterations are induced by stress, such as heart cell injury, the researchers next investigated the role of MCUB after heart attack in mice. In mice that suffered heart attack, the research team observed significant elevations in MCUB gene expression and decreases in MCU and the gatekeeper of the channel, MICU1. When genetically expressed prior to inducing a heart attack in mice, MCUB altered the channel to reduce calcium overload in the injured heart, ultimately curtailing tissue injury.
Dr. Elrod's team also found that, while it can improve cell survival after heart injury, increased MCUB activity comes at the expense of mitochondrial energy production. "MCUB induction is a compensatory change," explained Dr. Elrod. Just like an emergency responder, MCUB moves in and tries to reduce cell death and aid cell survival -- however, the reduction in mitochondrial calcium uptake is also maladaptive and limits the cell's ability to increase energy during stress.
"MCUB presents us with a new molecular target for investigation," Dr. Elrod said. "It's unique in that it alters the stoichiometry of the channel and thereby presents a new mechanism which may be amendable to therapeutic manipulation. We think that modulating MCUB may allow us to tune down mitochondrial calcium uptake without completely inhibiting all energetic function."
It is hoped that follow-up studies defining the exact sites of molecular interaction will provide additional insight into how to target mitochondrial calcium overload in heart disease.
https://www.sciencedaily.com/releases/2019/09/190919080749.htm