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Zanjan University of Medical Sciences

Neuroscientists Map Brain's Response to Cold Touch

 | Post date: 2018/07/1 | 
Neuroscientists have mapped the feeling of cool touch to the brain's insula in a mouse model.

 
 
Carnegie Mellon University neuroscientists have mapped the feeling of cool touch to the brain's insula in a mouse model. The findings, published in the Journal of Comparative Neurology, provide an experimental model that will advance research into conditions like pain and hypersensitivity to cold and help researchers to continue to unravel the multifaceted ways touch is represented in the brain.
"Touch is, by nature, multi-modal. When you pick something up, it can be warm, smooth and heavy all at once. Your brain divides that touch into all of these different percepts. Understanding how it does this can show us how the brain adapts and learns in response to touch and how changes in these pathways can cause pain and disease," said Alison Barth, professor of biological sciences in the Mellon College of Science and member of the joint Carnegie Mellon/University of Pittsburgh Center for the Basis of Neural Cognition.
Touch is a complex sense made up of different components like temperature, texture, weight and pressure -- for example, the smooth and heavy feel of a cold can of soda. Each of these tactile components can be represented in different parts of the brain, and parallel signals from the soda can will activate neurons in multiple areas of the brain, making it difficult to understand how any one of them is represented. Thermal sensation is particularly important, as these neural pathways are thought to overlap with pain, and chronic pain disorders often are associated with abnormal temperature sensitivity.
Although brain maps for touch sensation have been identified in humans, it has been an open question whether other animals share the same organization, a critical question that would enable new therapies to be developed and tested in animal models of disease. For example, reactions to pain and cold temperatures are seen in the insula in the human cerebral cortex.
Researchers believed that the rodent insula was far less complex, and reactions to these stimuli wouldn't be observed in the same place as those found in the human brain, Science Daily reported.
In the current experiment, the Carnegie Mellon researchers looked to establish what part of the mouse brain responded to cool touch. Cold is unique in that only one receptor, TrpM8, responds to cool thermal sensation. Using both cool touch and also exposure to menthol, the researchers were able to show that the feeling of cold was represented in the rodent insula in striking correspondence with the area of the brain activated in humans. Critically, this region was not activated in mice lacking the TrpM8 receptor, indicating that it was highly specific to cool exposure.
The researchers also found that they could trigger the TrpM8 receptors using inhaled menthol and see the same activation in the insula, providing an even more robust way to study this component of touch.
 

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Mindful Movement May Help Lower Stress, Anxiety

 | Post date: 2018/07/1 | 
Taking a walk may be a good opportunity to mentally review your to-do list, but using the time to instead be more mindful of your breathing and surroundings may help boost your wellbeing, according to researchers.

 

The researchers found that while students reported being less stressed while they were on their feet and moving, they received an even greater benefit when they reported also being more mindful.
Chih-Hsiang "Jason" Yang, a postdoctoral scholar at the University of Southern California who led the study while earning his doctorate at Penn State, said the results suggest a simple way for people to boost their wellbeing throughout the day.
"It can be difficult to ask people to spend a lot of time doing moderate or vigorous activity by going to the gym or out for a run, especially if they feel stressed," Yang said. "But if they don't need to change their everyday behavior, and can instead try to change their state of mind by becoming more mindful, they can probably see this beneficial effect. You don't need to exert a lot of extra effort in order to improve your wellbeing by being more mindful while you're moving around."
David Conroy, professor of kinesiology at Penn State, also said the findings -- recently published in the journal Psychology of Sports and Exercise -- could help people who are not able to engage in strenuous exercise.
"If someone is looking for a way to manage these kinds of feelings, it may be worth trying some sort of mindful movement," Conroy said. "This option may be especially beneficial for people who don't enjoy exercise and would prefer a less intense form of physical activity."
According to the American College Health Association, more than half of college students experience anxiety, sadness or mental exhaustion at least once a year, suggesting a need for a simple way to reduce these negative states. Because students are often moving throughout their days, as they walk to class and go about other activities, the researchers wanted to see if there was a connection between mindfulness, movement and a reduction in negative states.
The researchers recruited 158 Penn State students for the study. For two weeks, a special mobile phone app, called Paco, randomly prompted the participants eight times a day to answer questions about their current activity and states of mind. The prompts included questions about where the participant was, if they were moving, and if they were stressed or anxious, as well as questions designed to assess mindfulness.
After analyzing the data, the researchers found that in the moments when participants were more mindful or active than usual, they showed reduced negative affect. They also found a possible synergistic effect when people were both mindful and active.
"When people were both more mindful and more active than usual, they seem to have this extra decrease in negative affect," Yang said. "Being more active in a given moment is already going to reduce negative affect, but by also being more mindful than usual at the same time, you can see this amplified affect."
Conroy said it was interesting to see patterns emerge within the individual participants, instead of just comparing people who are generally more mindful to people who are generally less mindful.
"Most studies in this area have focused on the differences between people who are more versus people who are less mindful, but we saw that college students often slipped in and out of mindful states during the day," Conroy said. "Developing the ability to shift into these states of mindfulness as needed may be valuable for improving self-regulation and well-being."
To better explore the causal role of mindfulness on lower negative states of being, Yang completed a second study, in which older adults who participated in an outdoor mindfulness activity then reported on their feelings of stress, anxiety and depression. Yang found that the mindful walking was associated with lower levels of these feelings.
The researchers said that in the future, studies that collect more objective data -- like gathering information about physical activity by using accelerometers -- and include more varied populations could be useful.
 

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Scientists Discover How Antiviral Gene Works

 | Post date: 2018/07/1 | 
It's been known for years that humans and other mammals possess an antiviral gene called RSAD2 that prevents a remarkable range of viruses from multiplying. 
 

Now, researchers at Albert Einstein College of Medicine, part of Montefiore, have discovered the secret to the gene's success: The enzyme it codes for generates a compound that stops viruses from replicating. The newly discovered compound, described in online edition of Nature, offers a novel approach for attacking many disease-causing viruses.
"Nature has given us a template for creating a powerful and safe antiviral compound," says study leader Steven C. Almo, Ph.D., professor and chair of biochemistry, professor of physiology & biophysics and the Wollowick Family Foundation Chair in Multiple Sclerosis and Immunology at Einstein. Dr. Almo and his colleagues at Einstein and Pennsylvania State University found that the compound, called ddhCTP, disrupts the replication machinery of Zika virus. The next step is to test the compound against a broad array of viruses.
Dr. Almo predicts that modifications to ddhCTP could make it even more potent. Furthermore, he says, "drugs based on this compound may have a favorable safety profile. We've been living with ddhCTP for many millions of years and long ago developed mechanisms to prevent it from interfering with the replication of our own cells." Tyler Grove, Ph.D., a research assistant professor in Dr. Almo's lab, and Anthony Gizzi, who received his Ph.D. from Einstein in May, are co-lead authors on the study.
Finding How Viruses Are Vanquished
Mammalian cells that become infected by viruses and other pathogens release signaling proteins called interferons. The interferons in turn trigger the expression of hundreds of genes -- one of which is RSAD2, the gene that codes for the enzyme viperin (short for "virus inhibitory protein, endoplasmic reticulum-associated, interferon-inducible"). Studies have shown that viperin's expression inhibits a broad spectrum of disease-causing viruses, including hepatitis C, rabies and HIV-1.
Researchers had proposed several theories for how viperin exerts its anti-viral effects, but precisely how it acted was a mystery. The current study reveals that viperin catalyzes the conversion of a nucleotide called CTP (cytidine triphosphate) into a structurally similar compound, or analog: the nucleotide ddhCTP -- a previously undescribed molecule that sabotages viral replication.
Many viruses use CTP as a building block to synthesize the new strands of genetic material they need to replicate. The conversion of CTP to its analog, ddhCTP, throws a monkey wrench into virus' ability to copy its genome. The analogue's structure differs only slightly from CTP's -- but the difference is sufficient to bring viral replication to a halt.
Dr. Almo's colleagues at Pennsylvania State University showed in laboratory studies that ddhCTP was highly effective at inhibiting the replication of three different strains of Zika virus -- a mosquito-borne virus that causes an infection for which there is currently no treatment. "Based on our enzymology studies," says Dr. Almo, "we think that ddhCTP may be able to inhibit all flaviviruses, a class of viruses that includes Zika as well as dengue, West Nile, yellow fever, Japanese encephalitis and hepatitis C."
A Promising Platform for New Drugs
Dr. Almo says that ddhCTP appears to be "a completely novel drug scaffold" for designing antiviral drugs. "We are hoping we can generate variants of this molecule that will be even more effective," he adds. "Those drugs would be based on a naturally occurring molecule, so they could have few off-target effects -- a common problem with manmade nucleotide analogs, which can be effective but also quite toxic."

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High Salt Intake Associated with Doubled Risk of Heart failure

 | Post date: 2017/09/7 | 
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High salt intake is associated with a doubled risk of heart failure, according to a 12-year study in more than 4,000 people.
High salt intake is associated with a doubled risk of heart failure, according to a 12-year study in more than 4,000 people presented  at ESC (European Society of Cardiology) Congress.
"High salt (sodium chloride) intake is one of the major causes of high blood pressure and an independent risk factor for coronary heart disease (CHD) and stroke," said Prof Pekka Jousilahti, research professor at the National Institute for Health and Welfare, Helsinki, Finland. "In addition to CHD and stroke, heart failure is one of the major cardiovascular diseases in Europe and globally but the role of high salt intake in its development is unknown."
This study assessed the relationship of salt intake and the development of heart failure. Estimation of individual salt intake is methodologically demanding and therefore suitable population-based cohorts are rare. This study used 24 hour sodium extraction, which is considered the gold standard for salt intake estimation at individual level.
This was a prospective follow-up study of 4 630 randomly selected men and women aged 25 to 64 years at baseline who participated in the North Karelia Salt Study and the National FINRISK Study between 1979 and 2002 in Finland. Baseline data collection included a self-administered questionnaire on health behaviour, measurements of weight, height and blood pressure, a venous blood sample for laboratory analysis, and collection of a 24 hour urine sample.
At the study site, nurses measured urine volume and took a 100 ml sample for laboratory analysis. One gram of salt intake was calculated as equal to 17.1 mmol sodium excretion, Science Daily reported.
The study cohort was followed up for 12 years through computerised register linkage to National Health Records. Cases of incident heart failure were identified from the Causes of Death Register, the Hospital Discharge Register and drug reimbursement records. The association of salt intake in quintiles (<6.8g, 6.8-8.8g, 8.8-10.9g, 10.96-13.7g and >13.7g/day) and the risk of an incident new heart failure event was estimated.
During the follow-up, 121 men and women developed new heart failure. In an age, sex, study year and area adjusted model, hazard ratios in the 2nd, 3rd, 4th and 5th salt intake quintiles, compared to the 1st one, were: 0.83, 1.40, 1.70 and 2.10. After further adjustment for systolic blood pressure, serum total cholesterol level and body mass index the hazard ratios were: 1.13, 1.45, 1.56 and 1.75, respectively.
Prof Jousilahti said: "The heart does not like salt. High salt intake markedly increases the risk of heart failure. This salt-related increase in heart failure risk was independent of blood pressure."
"People who consumed more than 13.7 grams of salt daily had a two times higher risk of heart failure compared to those consuming less than 6.8 grams," he continued. "The optimal daily salt intake is probably even lower than 6.8 grams. The World Health Organization recommends a maximum of 5 grams per day and the physiological need is 2 to 3 grams per day."
Prof Jousilahti concluded: "Studies in larger, pooled population cohorts are needed to make more detailed estimations of the increased heart failure risk associated with consuming salt."

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Why Is Yawning so Contagious?

 | Post date: 2017/09/7 | 
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Experts published a research that suggests the human propensity for contagious yawning is triggered automatically by primitive reflexes in the primary motor cortex - an area of the brain responsible for motor function.

Feeling tired? Even if we aren't tired, why do we yawn if someone else does? Experts at the University of Nottingham have an explanation.
Their study, “A neural basis for contagious yawning”, has been published in the academic journal Current Biology. It is another stage in their research into the underlying biology of neuropsychiatric disorders and their search for new methods of treatment.
Their latest findings show that our ability to resist yawning when someone else near us yawns is limited. And our urge to yawn is increased if we are instructed to resist yawning. But, no matter how hard we try to stifle a yawn, it might change how we yawn but it won't alter our propensity to yawn. Importantly, they have discovered that the urge to yawn -our propensity for contagious yawning- is individual to each one of us.
Stephen Jackson, Professor of Cognitive Neuroscience, in the School of Psychology, led the multidisciplinary study.
Contagious yawning is triggered involuntarily when we observe another person yawn -it is a common form of echophenomena- the automatic imitation of another's words (echolalia) or actions (echopraxia). And it's not just humans who have a propensity for contagious yawning -chimpanzees and dogs do it too.
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Georgina Jackson, Professor of Cognitive Neuropsychology in the Institute of Mental Health, said, "This research has shown that the 'urge' is increased by trying to stop yourself. Using electrical stimulation we were able to increase excitability and in doing so increase the propensity for contagious yawning. In Tourettes if we could reduce the excitability we might reduce the ticks and that's what we are working on."


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