(Press-News.org) If you can't tell a smile from a scowl, you're probably not getting enough sleep.
"Recognizing the emotional expressions of someone else changes everything about whether or not you decide to interact with them, and in return, whether they interact with you," said study senior author Matthew Walker, a professor of psychology and neuroscience at UC Berkeley. The findings were published today in the Journal of Neuroscience.
"These findings are especially worrying considering that two-thirds of people in the developed nations fail to get sufficient sleep," Walker added.
Indeed, the results do not bode well for countless sleep-starved groups, said study lead author Andrea Goldstein-Piekarski, a postdoctoral fellow at Stanford University, who started the study as a Ph.D. student at UC Berkeley.
"Consider the implications for students pulling all-nighters, emergency-room medical staff, military fighters in war zones and police officers on graveyard shifts," she said.
For the experiment, 18 healthy young adults viewed 70 facial expressions that ranged from friendly to threatening, once after a full night of sleep, and once after 24 hours of being awake. Researchers scanned participants' brains and measured their heart rates as they looked at the series of visages.
Brain scans as they carried out these tasks - generated through functional Magnetic Resonance Imaging (fMRI) - revealed that the sleep-deprived brains could not distinguish between threatening and friendly faces, specifically in the emotion-sensing regions of the brain's anterior insula and anterior cingulate cortex.
Additionally, the heart rates of sleep-deprived study participants did not respond normally to threatening or friendly facial expressions. Moreover, researchers found a disconnection in the neural link between the brain and heart that typically enables the body to sense distress signals.
"Sleep deprivation appears to dislocate the body from the brain," said Walker. "You can't follow your heart."
As a consequence, study participants interpreted more faces, even the friendly or neutral ones, as threatening when sleep-deprived.
"They failed our emotional Rorschach test," Walker said. "Insufficient sleep removes the rose tint to our emotional world, causing an overestimation of threat. This may explain why people who report getting too little sleep are less social and more lonely."
On a more positive note, researchers recorded the electrical brain activity of the participants during their full night of sleep, and found that their quality of Rapid Eye Movement (REM) or dream sleep correlated with their ability to accurately read facial expressions. Previous research by Walker has found that REM sleep serves to reduce stress neurochemicals and soften painful memories.
"The better the quality of dream sleep, the more accurate the brain and body was at differentiating between facial expressions," Walker said. "Dream sleep appears to reset the magnetic north of our emotional compass. This study provides yet more proof of our essential need for sleep."
INFORMATION:
University of Adelaide researchers have shown that intelligence in animal species can be estimated by the size of the holes in the skull through which the arteries pass.
Published online ahead of print in the Journal of Experimental Biology, the researchers in the School of Biological Sciences show that the connection between intelligence and hole size stems from brain activity being related to brain metabolic rate.
"A human brain contains nearly 100 billion nerve cells with connections measured in the trillions," says project leader, Professor Emeritus Roger Seymour. ...
An international team of researchers, including investigators from the University of Mississippi Medical Center (UMMC), has identified a gene that underlies healthy information processing -- a first step on a complicated road to understand cognitive aging and age-related diseases, such as Alzheimer's disease.
The study, published online and expected to come out this fall in a print edition of the journal Molecular Psychiatry, is one of the the largest genetics study to date to link a specific genetic mutation and information processing speed.
"It is well known that ...
Special efforts should be made to identify and treat depression and urinary incontinence in postmenopausal women with vaginal symptoms, according to UC San Francisco researchers, as these two common conditions not only tend to co-exist with vaginal symptoms but also may complicate the impact of these symptoms on women's daily activities and quality of life.
The study appears online on July 15, 2015, in Menopause and will be featured in the January 2016 print edition.
"Our findings suggest that depression and urinary incontinence may magnify the effects of vaginal symptoms ...
Hydrogen fuel cells promise clean cars that emit only water. Several major car manufacturers have recently announced their investment to increase the availability of fueling stations, while others are rolling out new models and prototypes. However, challenges remain, including the chemistry to produce and use hydrogen and oxygen gas efficiently. Today, in ACS Central Science, two research teams report advances on chemical reactions essential to fuel-cell technology in separate papers.
Hydrogen (H2) fuel cells react H2 and oxygen (O2) gases to produce energy. For that ...
The perceived trustworthiness of an inmate's face may determine the severity of the sentence he receives, according to new research using photos and sentencing data for inmates in the state of Florida. The research, published in Psychological Science, a journal of the Association for Psychological Science, reveals that inmates whose faces were rated as low in trustworthiness by independent observers were more likely to have received the death sentence than inmates whose faces were perceived as more trustworthy, even when the inmates were later exonerated of the crime.
"The ...
COLUMBUS, Ohio - Research has suggested yellow perch grow more rapidly during the short winters resulting from climate change, but a new study shows warmer water temperatures can lead to the production of less hardy eggs and larvae that have trouble surviving these early stages of life in Lake Erie.
The research also showed that yellow perch don't adjust spawning to match earlier spring-like temperatures. This poses a problem if the hatchlings' main food source, zooplankton, does make a temperature-based adjustment because supplies may be low by the time larvae are ready ...
Species invasions come at a high cost. In the United States, the annual cost to the economy tops $100 billion a year and invasive plant infestations affect 100 million acres. While it's tempting to focus attention on headline-grabbing cases of exceptionally fecund flora such as the kudzu vine, also known as "the vine that ate the South", basic questions remain about how and whether exotic species are functionally distinct from native species and why they tend to take over when introduced into new environments.
A new study, led by University of Minnesota College of Biological ...
When a rhythm stalls, the effect can be fatal - in a power grid it can mean a blackout, and in the human heart even death. An international team of scientists has now developed a new approach for revoking these undesired quenching states. They use an advanced mathematical methodology, building on complex networks analysis, and demonstrate it in experiments with chemical reactions.
This could one day help to stabilize the flow of electricity in power grids challenged by the variable input from renewable energy sources. Future research could apply it to other complex networks, ...
Millimetre-sized crystals of high-quality graphene can be made in minutes instead of hours using a new scalable technique, Oxford University researchers have demonstrated.
In just 15 minutes the method can produce large graphene crystals around 2-3 millimetres in size that it would take up to 19 hours to produce using current chemical vapour deposition (CVD) techniques in which carbon in gas reacts with, for example, copper to form graphene.
Graphene promises to be a 'wonder material' for building new technologies because of its combination of strength, flexibility, ...
Updated guidelines on the treatment of idiopathic pulmonary fibrosis (IPF) have been released by an international group of leading respiratory societies, The new guidelines, issued by the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association, were published in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.
"In these updated guidelines, we analyzed new evidence reported since our 2011 guideline was issued and updated our treatment recommendations ...
