How associative fear memory is formed in the brain

March 13, 2020

Science Daily/University of California - Riverside

How does the brain form "fear memory" that links a traumatic event to a particular situation? A pair of researchers at the University of California, Riverside, may have found an answer.

Using a mouse model, the researchers demonstrated the formation of fear memory involves the strengthening of neural pathways between two brain areas: the hippocampus, which responds to a particular context and encodes it, and the amygdala, which triggers defensive behavior, including fear responses.

Study results appear today in Nature Communications.

"It has been hypothesized that fear memory is formed by strengthening the connections between the hippocampus and amygdala," said Jun-Hyeong Cho, an assistant professor in the Department of Molecular, Cell and Systems Biology and the study's lead author. "Experimental evidence, however, has been weak. Our study now demonstrates for the first time that the formation of fear memory associated with a context indeed involves the strengthening of the connections between the hippocampus and amygdala."

According to Cho, weakening these connections could erase the fear memory.

"Our study, therefore, also provides insights into developing therapeutic strategies to suppress maladaptive fear memories in post-traumatic stress disorder patients," he said.

Post-traumatic stress disorder, or PTSD, affects 7% of the U.S. population. A psychiatric disorder that can occur in people who have experienced or witnessed a traumatic event, such as war, assault, or disaster, PTSD can cause problems in daily life for months, and even years, in affected persons.

Cho explained the capability of our brains to form a fear memory associated with a situation that predicts danger is highly adaptive since it enables us to learn from our past traumatic experiences and avoid those dangerous situations in the future. This process is dysregulated, however, in PTSD, where overgeneralized and exaggerated fear responses cause symptoms including nightmares or unwanted memories of the trauma, avoidance of situations that trigger memories of the trauma, heightened reactions, anxiety, and depressed mood.

"The neural mechanism of learned fear has an enormous survival value for animals, who must predict danger from seemingly neutral contexts," Cho said. "Suppose we had a car accident in a particular place and got severely injured. We would then feel afraid of that -- or similar -- place even long after we recover from the physical injury. This is because our brains form a memory that associates the car accident with the situation where we experienced the trauma. This associative memory makes us feel afraid of that, or similar, situation and we avoid such threatening situations."

According to Cho, during the car accident, the brain processes a set of multisensory circumstances around the traumatic event, such as visual information about the place, auditory information such as a crash sound, and smells of burning materials from damaged cars. The brain then integrates these sensory signals as a highly abstract form -- the context -- and forms a memory that associates the traumatic event with the context.

The researchers also plan to develop strategies to suppress pathological fear memories in PTSD.

https://www.sciencedaily.com/releases/2020/03/200313112137.htm

How hearing loss in old age affects the brain

April 23, 2020

Science Daily/Ruhr-University Bochum

If your hearing deteriorates in old age, the risk of dementia and cognitive decline increases. So far, it hasn't been clear why. A team of neuroscientists has examined what happens in the brain when hearing gradually deteriorates: key areas of the brain are reorganized, and this affects memory.

Daniela Beckmann, Mirko Feldmann, Olena Shchyglo and Professor Denise Manahan-Vaughan from the Department of Neurophysiology of the Medical Faculty worked together for the study.

When sensory perception fades

The researchers studied the brain of mice that exhibit hereditary hearing loss, similar to age related hearing loss in humans. The scientists analysed the density of neurotransmitter receptors in the brain that are crucial for memory formation. They also researched the extent to which information storage in the brain's most important memory organ, the hippocampus, was affected.

Adaptability of the brain suffers

Memory is enabled by a process called synaptic plasticity. In the hippocampus, synaptic plasticity was chronically impaired by progressive hearing loss. The distribution and density of neurotransmitter receptors in sensory and memory regions of the brain also changed constantly. The stronger the hearing impairment, the poorer were both synaptic plasticity and memory ability.

"Our results provide new insights into the putative cause of the relationship between cognitive decline and age-related hearing loss in humans," said Denise Manahan-Vaughan. "We believe that the constant changes in neurotransmitter receptor expression caused by progressive hearing loss create shifting sands at the level of sensory information processing that prevent the hippocampus from working effectively," she adds.

https://www.sciencedaily.com/releases/2020/04/200423130446.htm

Vegetarians tend to be slimmer and less extroverted than meat eaters

June 15, 2020

Science Daily/Max Planck Institute for Human Cognitive and Brain Sciences

The less animal products someone consumes, the lower his body mass index on average and the less he tends to be extroverted. A connection with depressive moods as other studies had found could not be confirmed.

According to a survey by the Allensbach Institute, more than 6.1 million Germans stated last year that they were vegetarians, 400,000 more than two years earlier. A large-scale study at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) in cooperation with the University Hospital of Leipzig has now examined in almost 9,000 people how this form of nutrition is related to the body and the psyche -- regardless of age, gender and level of education.

It was found that the rarer the proportion of animal food in a person's diet, the lower their body mass index (BMI) on average and thus their body weight. One reason for this could be the lower proportion of heavily processed foods in the plant diet. "Products that are excessively rich in fat and sugar are particularly fattening. They stimulate the appetite and delay the feeling of satiety. If you avoid animal foods, you consume fewer such products on average," explains Evelyn Medawar, first author of the underlying publication, which has now been published in the journal Nutrients. In addition: Vegetarian food contains dietary fibres and has a positive effect on the microbiome in the intestine. This is another reason why they could fill you up earlier than those made from animal ingredients. "People who eat predominantly vegetable foods may therefore absorb less energy," Medawar adds. In addition to a changed feeling of satiety, lifestyle factors such as more sport and greater health awareness could also play a decisive role.

For the BMI it also seems to make a difference which animal products a person feeds on. If it is predominantly so-called primary animal products, i.e. meat, sausage and fish, the person usually has a higher BMI than someone who eats primarily secondary animal products, i.e. eggs, milk, dairy products, cheese and butter. In the former case the correlation is statistically significant.

Medawar uses an example to illustrate what this could mean for nutrition: "A person with a 1.2 point lower BMI on average either completely avoids certain animal products, such as the primary ones, and is on a vegetarian diet. Or she continues to eat meat and fish, but less often. Whether nutrition is ultimately the cause of lower body weight or whether other factors are responsible for it cannot be determined from the data. A follow-up study in cooperation with the University Hospital Leipzig will now shed light on this.

Nutrition and personality

The researchers also found out that vegetarian or vegan nutrition is also related to personality. Especially with one of the five major personality factors, extroversion. It was shown that people with predominantly plant-based foods on their diet are more introverted than those who mainly fed on animal products. "It is difficult to say what the reason for this is," says Veronica Witte. "It could be because more introverted people tend to have more restrictive eating habits or because they are more socially segregated because of their eating habits." Here, again, further studies should follow on how people identify with the characteristics of their diet.

However, they could not confirm that a plant-based diet is associated with a tendency towards neurotic behaviour, as other studies suggested. "Earlier analyses had found that more neurotic people were generally more likely to avoid certain groups of foods and to behave more restrictively. We focused here solely on the avoidance of animal products and could not observe any correlation," explains study leader Veronica Witte.

In a third part, they finally concentrated on the question of whether a predominantly plant-based diet is more often associated with depressive moods. Here previous studies had also suggested a relationship between the two factors. "We could not detect this correlation," says Witte. "It is possible that in previous analyses other factors had blurred the results, including the BMI or conspicuous personality traits that are known to be associated with depression. We accounted for them," said Witte explaining a possible reason for the different results. In addition, the plant-based diet is now more common and more accepted and not anymore restricted to a certain group.

The scientists had investigated these connections within the so-called LIFE project, a broad-based study in cooperation with the University Hospital of Leipzig. They determined the personal diets by means of questionnaires in which the participants were asked to fill in how often they had eaten the individual animal products in the last 12 months -- from "several times a day" to "never." The personality traits such as extroversion and neuroticism were assessed by means of a so-called personality inventory (NEOFFI), while depression was assessed by means of the so-called CESD test, a questionnaire that records various symptoms of depression.

https://www.sciencedaily.com/releases/2020/06/200615115748.htm

Our ability to focus may falter after eating one meal high in saturated fat

Study also looks at effect of leaky gut on concentration

May 12, 2020

Science Daily/Ohio State University

Fatty food may feel like a friend during these troubled times, but new research suggests that eating just one meal high in saturated fat can hinder our ability to concentrate -- not great news for people whose diets have gone south while they're working at home during the COVID-19 pandemic.

The study compared how 51 women performed on a test of their attention after they ate either a meal high in saturated fat or the same meal made with sunflower oil, which is high in unsaturated fat.

Their performance on the test was worse after eating the high-saturated-fat meal than after they ate the meal containing a healthier fat, signaling a link between that fatty food and the brain.

Researchers were also looking at whether a condition called leaky gut, which allows intestinal bacteria to enter the bloodstream, had any effect on concentration. Participants with leakier guts performed worse on the attention assessment no matter which meal they had eaten.

The loss of focus after a single meal was eye-opening for the researchers.

"Most prior work looking at the causative effect of the diet has looked over a period of time. And this was just one meal -- it's pretty remarkable that we saw a difference," said Annelise Madison, lead author of the study and a graduate student in clinical psychology at The Ohio State University.

Madison also noted that the meal made with sunflower oil, while low in saturated fat, still contained a lot of dietary fat.

"Because both meals were high-fat and potentially problematic, the high-saturated-fat meal's cognitive effect could be even greater if it were compared to a lower-fat meal," she said.

The study is published in the American Journal of Clinical Nutrition.

Madison works in the lab of Janice Kiecolt-Glaser, professor of psychiatry and psychology and director of the Institute for Behavioral Medicine Research at Ohio State. For this work, Madison conducted a secondary analysis of data from Kiecolt-Glaser's study assessing whether high-fat meals increased fatigue and inflammation among cancer survivors.

Women in the study completed a baseline assessment of their attention during a morning visit to the lab. The tool, called a continuous performance test, is a measure of sustained attention, concentration and reaction time based on 10 minutes of computer-based activities.

The high-fat meal followed: eggs, biscuits, turkey sausage and gravy containing 60 grams of fat, either a palmitic acid-based oil high in saturated fat or the lower-saturated-fat sunflower oil. Both meals totaled 930 calories and were designed to mimic the contents of various fast-food meals such as a Burger King double whopper with cheese or a McDonald's Big Mac and medium fries.

Five hours later, the women took the continuous performance test again. Between one and four weeks later, they repeated these steps, eating the opposite meal of what they had eaten on the first visit.

Researchers also analyzed participants' fasting baseline blood samples to determine whether they contained an inflammatory molecule that signals the presence of endotoxemia -- the toxin that escapes from the intestines and enters the bloodstream when the gut barrier is compromised.

After eating the meal high in saturated fat, all of the participating women were, on average, 11 percent less able to detect target stimuli in the attention assessment. Concentration lapses were also apparent in the women with signs of leaky gut: Their response times were more erratic and they were less able to sustain their attention during the 10-minute test.

"If the women had high levels of endotoxemia, it also wiped out the between-meal differences. They were performing poorly no matter what type of fat they ate," Madison said.

Though the study didn't determine what was going on in the brain, Madison said previous research has suggested that food high in saturated fat can drive up inflammation throughout the body, and possibly the brain. Fatty acids also can cross the blood-brain barrier.

"It could be that fatty acids are interacting with the brain directly. What it does show is the power of gut-related dysregulation," she said.

The statistical analysis accounted for other potential influences on cognition, including depressive symptoms and the participants' average dietary saturated fat consumption. The women in the study ate three standardized meals and fasted for 12 hours before each lab visit to reduce diet variations that could affect their physiological response to the high-fat meals.

The findings suggest concentration could be even more impaired in people stressed by the pandemic who are turning to fatty foods for comfort, Kiecolt-Glaser said.

"What we know is that when people are more anxious, a good subset of us will find high-saturated-fat food more enticing than broccoli," she said. "We know from other research that depression and anxiety can interfere with concentration and attention as well. When we add that on top of the high-fat meal, we could expect the real-world effects to be even larger."

https://www.sciencedaily.com/releases/2020/05/200512134433.htm

Certain foods common in diets of US adults with inflammatory bowel disease

May 6, 2020

Science Daily/Georgia State University

Foods, such as French fries, cheese, cookies, soda, and sports and energy drinks, are commonly found in the diets of United States adults with inflammatory bowel disease, according to a new study by researchers in the Institute for Biomedical Sciences at Georgia State University.

The researchers analyzed the National Health Interview Survey 2015 to determine the food intake and frequency of consumption for U.S. adults with inflammatory bowel disease. The survey assessed 26 foods. The findings, published in the journal PLOS One, reveal that foods typically labeled as junk food were associated with inflammatory bowel disease.

Inflammatory bowel disease, which is characterized by chronic inflammation of the gastrointestinal tract, affects three million U.S. adults. There are two types of conditions, Crohn's disease and ulcerative colitis. Common symptoms of inflammatory bowel disease include persistent diarrhea, abdominal pain, rectal bleeding or bloody stools, weight loss and fatigue, according to the Centers for Disease Control and Prevention (CDC).

This study found fries were consumed by a greater number of people with inflammatory bowel disease, and they also ate more cheese and cookies and drank less 100 percent fruit juice compared to people who did not have inflammatory bowel disease.

Intaking fries and sports and energy drinks and frequently drinking soda were significantly associated with having been told one has inflammatory bowel disease. Consuming milk or popcorn was less likely associated with receiving this diagnosis.

"While foods typically labeled as junk food were positively associated with inflammatory bowel disease, we found the eating patterns of people with and without this disease to be very similar," said Dr. Moon Han, the study's first author who completed the work as a Ph.D. student in Dr. Didier Merlin's lab in the Institute for Biomedical Sciences and now works as a Health Scientist ORISE Fellow at the CDC. "However, it's unclear whether the survey results reflect a potential change in the food intake of people with inflammatory bowel disease long before the survey was conducted."

To fully understand the role of food intake in inflammatory bowel disease risk and prevalence, it's important to explore environmental factors (for example, food deserts), food processing (such as frying) and potential bioactive food components that can induce intestinal inflammation and increase susceptibility to inflammatory bowel disease, the researchers concluded.

https://www.sciencedaily.com/releases/2020/05/200506162150.htm#

Which foods do you eat together? How you combine them may raise dementia risk

Study finds 'food networks' centered on processed meats, starches may raise risk

April 22, 2020

Science Daily/American Academy of Neurology

t's no secret that a healthy diet may benefit the brain. However, it may not only be what foods you eat, but what foods you eat together that may be associated with your risk of dementia, according to a new study published in the April 22, 2020, online issue of Neurology®, the medical journal of the American Academy of Neurology. The study looked at "food networks" and found that people whose diets consisted mostly of highly processed meats, starchy foods like potatoes, and snacks like cookies and cakes, were more likely to have dementia years later compared to people who ate a wider variety of healthy foods.

"There is a complex inter-connectedness of foods in a person's diet, and it is important to understand how these different connections, or food networks, may affect the brain because diet could be a promising way to prevent dementia," said study author Cécilia Samieri, PhD, of the University of Bordeaux in France. "A number of studies have shown that eating a healthier diet, for example a diet rich in green leafy vegetables, berries, nuts, whole grains and fish, may lower a person's risk of dementia. Many of those studies focused on quantity and frequency of foods. Our study went one step further to look at food networks and found important differences in the ways in which food items were co-consumed in people who went on to develop dementia and those who did not."

The study involved 209 people with an average age of 78 who had dementia and 418 people, matched for age, sex and educational level, who did not have dementia.

Participants had completed a food questionnaire five years previously describing what types of food they ate over the year, and how frequently, from less than once a month to more than four times a day. They also had medical checkups every two to three years. Researchers used the data from the food questionnaire to compare what foods were often eaten together by the patients with and without dementia.

Researchers found while there were few differences in the amount of individual foods that people ate, overall food groups or networks differed substantially between people who had dementia and those who did not have dementia.

"Processed meats were a 'hub' in the food networks of people with dementia," said Samieri. "People who developed dementia were more likely to combine highly processed meats such as sausages, cured meats and patés with starchy foods like potatoes, alcohol, and snacks like cookies and cakes. This may suggest that frequency with which processed meat is combined with other unhealthy foods, rather than average quantity, may be important for dementia risk. For example, people with dementia were more likely, when they ate processed meat, to accompany it with potatoes and people without dementia were more likely to accompany meat with more diverse foods, including fruit and vegetables and seafood."

Overall, people who did not have dementia were more likely to have a lot of diversity in their diet, demonstrated by many small food networks that usually included healthier foods, such as fruit and vegetables, seafood, poultry or meats.

"We found that more diversity in diet, and greater inclusion of a variety of healthy foods, is related to less dementia," said Samieri. "In fact, we found differences in food networks that could be seen years before people with dementia were diagnosed. Our findings suggest that studying diet by looking at food networks may help untangle the complexity of diet and biology in health and disease."

One limitation of the study was that participants completed a food questionnaire that relied on their ability to accurately recall diet rather than having researchers monitor their diets. Another limitation was that diets were only recorded once, years before the onset of dementia, so any changes in diet over time were unknown.

https://www.sciencedaily.com/releases/2020/04/200422214038.htm

Link between obesity and sleep loss

Energy conservation may be a major function of sleep, according to new study in worms

April 22, 2020

Science Daily/University of Pennsylvania School of Medicine

Can staying up late make you fat? A growing body of research has suggested that poor sleep quality is linked to an increased risk of obesity by deregulating appetite, which in turn leads to more calorie consumption.

But a new study published this week in PLOS Biology found that the direction of this reaction might actually be flipped: It's not the sleep loss that leads to obesity, but rather that excess weight can cause poor sleep, according to researchers from the University of Pennsylvania's Perelman School of Medicine and the University of Nevada, Reno, who discovered their findings in the microscopic worm Caenorhabditis elegans (C. elegans).

"We think that sleep is a function of the body trying to conserve energy in a setting where energetic levels are going down. Our findings suggest that if you were to fast for a day, we would predict you might get sleepy because your energetic stores would be depleted," said study co-author David Raizen, MD, PhD, an associate professor of Neurology and member of the Chronobiology and Sleep Institute at Penn.

Raizen emphasized that while these findings in worms may not translate directly to humans, C. elegans offer a surprisingly good model for studying mammalian slumber. Like all other animals that have nervous systems, they need sleep. But unlike humans, who have complex neural circuitry and are difficult to study, a C. elegans has only 302 neurons -- one of which scientists know for certain is a sleep regulator.

In humans, acute sleep disruption can result in increased appetite and insulin resistance, and people who chronically get fewer than six hours of sleep per night are more likely be obese and diabetic. Moreover, starvation in humans, rats, fruit flies, and worms has been shown to affect sleep, indicating that it is regulated, at least in part, by nutrient availability. However, the ways in which sleeping and eating work in tandem has remained unclear.

"We wanted to know, what is sleep actually doing? Short sleep and other chronic conditions, like diabetes, are linked, but it's just an association. It's not clear if short sleep is causing the propensity for obesity, or that the obesity, perhaps, causes the propensity for short sleep," said study co-author Alexander van der Linden, PhD, an associate professor of Biology at the University of Nevada, Reno.

To study the association between metabolism and sleep, the researchers genetically modified C. elegans to "turn off" a neuron that controls sleep. These worms could still eat, breathe, and reproduce, but they lost their ability to sleep. With this neuron turned off, the researchers saw a severe drop in adenosine triphosphate (ATP) levels, which is the body's energy currency.

"That suggests that sleep is an attempt to conserve energy; it's not actually causing the loss of energy," Raizen explained.

In previous research, the van der Linden lab studied a gene in C. elegans called KIN-29. This gene is homologous to the Salt-Inducible Kinase (SIK-3) gene in humans, which was already known to signal sleep pressure. Surprisingly, when the researchers knocked out the KIN-29 gene to create sleepless worms, the mutant C. elegans accumulated excess fat -- resembling the human obesity condition -- even though their ATP levels lowered.

The researchers hypothesized that the release of fat stores is a mechanism for which sleep is promoted, and that the reason KIN-29 mutants did not sleep is because they were unable to liberate their fat. To test this hypothesis, the researchers again manipulated the KIN-29 mutant worms, this time expressing an enzyme that "freed" their fat. With that manipulation, the worms were again able to sleep.

Raizen said this could explain one reason why people with obesity may experience sleep problems. "There could be a signaling problem between the fat stores and the brain cells that control sleep," he said.

While there is still much to unravel about sleep, Raizen said that this paper takes the research community one step closer to understanding one of its core functions -- and how to treat common sleep disorders.

"There is a common, over-arching sentiment in the sleep field that sleep is all about the brain, or the nerve cells, and our work suggests that this isn't necessarily true," he said. "There is some complex interaction between the brain and the rest of the body that connects to sleep regulation."

https://www.sciencedaily.com/releases/2020/04/200422091205.htm

Diet may help preserve cognitive function

April 14, 2020

Science Daily/NIH/National Eye Institute

According to a recent analysis of data from two major eye disease studies, adherence to the Mediterranean diet -- high in vegetables, whole grains, fish, and olive oil -- correlates with higher cognitive function. Dietary factors also seem to play a role in slowing cognitive decline. Researchers at the National Eye Institute (NEI), part of the National Institutes of Health, led the analysis of data from the Age-Related Eye Disease Study (AREDS) and AREDS2. They published their results today in the journal Alzheimer's and Dementia.

"We do not always pay attention to our diets. We need to explore how nutrition affects the brain and the eye" said Emily Chew, M.D., director of the NEI Division of Epidemiology and Clinical Applications and lead author of the studies.

The researchers examined the effects of nine components of the Mediterranean diet on cognition. The diet emphasizes consumption of whole fruits, vegetables, whole grains, nuts, legumes, fish, and olive oil, as well as reduced consumption of red meat and alcohol.

AREDS and AREDS2 assessed over years the effect of vitamins on age-related macular degeneration (AMD), which damages the light-sensitive retina. AREDS included about 4,000 participants with and without AMD, and AREDS2 included about 4,000 participants with AMD. The researchers assessed AREDS and AREDS2 participants for diet at the start of the studies. The AREDS study tested participants' cognitive function at five years, while AREDS2 tested cognitive function in participants at baseline and again two, four, and 10 years later. The researchers used standardized tests based on the Modified Mini-Mental State Examination to evaluate cognitive function as well as other tests. They assessed diet with a questionnaire that asked participants their average consumption of each Mediterranean diet component over the previous year.

Participants with the greatest adherence to the Mediterranean diet had the lowest risk of cognitive impairment. High fish and vegetable consumption appeared to have the greatest protective effect. At 10 years, AREDS2 participants with the highest fish consumption had the slowest rate of cognitive decline.

The numerical differences in cognitive function scores between participants with the highest versus lowest adherence to a Mediterranean diet were relatively small, meaning that individuals likely won't see a difference in daily function. But at a population level, the effects clearly show that cognition and neural health depend on diet.

The researchers also found that participants with the ApoE gene, which puts them at high risk for Alzheimer's disease, on average had lower cognitive function scores and greater decline than those without the gene. The benefits of close adherence to a Mediterranean diet were similar for people with and without the ApoE gene, meaning that the effects of diet on cognition are independent of genetic risk for Alzheimer's disease.

https://www.sciencedaily.com/releases/2020/04/200414084316.htm

Larger thighs associated with lower risk of heart disease in obesity

April 4, 2020

Science Daily/Society for Endocrinology

A larger thigh circumference may be associated with lower blood pressure and a reduced risk of heart disease in people with obesity, according to a study published in Endocrine Connections. In overweight and obese Chinese men and women, larger thigh circumferences were associated with lower blood pressure. These findings suggest that carrying more weight on the thighs may be a marker of better heart health in Chinese obese and overweight people, who are at a greater risk of heart disease. Thigh circumference may be useful for targeting obese and overweight people for earlier detection high blood pressure.

High blood pressure is a major public health problem affecting more than 1 billion people worldwide and is the leading cause of mortality and disability globally. A number of factors can increase risk of high blood pressure, such as being overweight, lack of exercise, smoking, or a high amount of salt in the diet. Elevated blood pressure causes excess strain on the heart and arteries and can lead to build-up of fat in blood vessels, limiting blood flow. This increases the risk of serious health conditions such as heart disease and stroke.

Many people are unaware they have high blood pressure as it rarely has noticeable symptoms. Therefore, identifying high risk individuals early and employing intervention strategies such as monitoring diet or increasing exercise may help prevent further damage to blood vessels and the heart.

Circumference measurements are easy, low cost and previously effective at evaluating risk of certain diseases -- a large waist circumference is well known to be associated with elevated blood pressure and a small thigh circumference is associated with diabetes. However, there are currently no studies that examine the potential of thigh circumference as an indicator of high blood pressure in people with obesity.

Dr Zhen Yang from Shanghai Jiao Tong University School of Medicine investigated the association between thigh circumference and blood pressure in a population of 9,250 Chinese men and women aged 40 or older, of which 5,348 were overweight and obese, and 4,172 were normal weight.

A significant link between larger thigh circumference (more than 55cm in men and 54cm in women) and lower prevalence of high blood pressure was observed consistently in both men and women, independently of age, body mass index, and waist circumference. Whereas those with a small thigh circumference (less than 50cm for women and 51cm for men) were more likely to have elevated blood pressure.

"In contrast to stomach fat, leg fat may be beneficial for metabolism. The most likely cause of this association is that there is more thigh muscle and/or fat deposited under the skin which secretes various beneficial substances that help keep blood pressure in a relatively stable range." Dr Yang explains.

These findings suggest that thigh circumference could potentially be used as a convenient and inexpensive indicator for earlier detection and prevention of high blood pressure and other related complications, such as heart disease, in obese or overweight people. However, due to large differences in thigh circumferences among different races and different physical activity groups, the thigh circumference sizes in this study may not be a reference for other populations.

Dr Yang now plans to further investigate this association by measuring body composition including thigh fat mass, thigh muscle mass, thigh bone mass and thigh proteins. Different proportions of these components may provide clues to the association between thigh circumference and blood pressure and may help us develop future treatments.

https://www.sciencedaily.com/releases/2020/04/200404155609.htm

To reap heart benefits of a plant-based diet, avoid junk food

Plant-based diet found to reduce cardiovascular risk, but only if foods are healthful

March 18, 2020

Science Daily/American College of Cardiology

Plant-based diets are becoming more popular in many areas of the world, but the health benefits of this dietary pattern may depend largely on the specific foods consumed. A new study being presented at the American College of Cardiology's Annual Scientific Session Together with World Congress of Cardiology (ACC.20/WCC) suggests that people following a plant-based diet who frequently consumed less-healthful foods like sweets, refined grains and juice showed no heart health benefit compared with those who did not eat a plant-based diet.

"Based on these results, it seems that simply following a plant-based or vegetarian diet is not enough to reduce cardiovascular disease risk," said Demosthenes Panagiotakos, PhD, professor of biostatistics, research methods and epidemiology at Harokopio University of Athens, Greece and the study's lead author. "It is also important to focus on specific, healthful plant-based food groups to see a benefit in terms of reducing cardiovascular disease."

Researchers tracked eating behavior and the development of heart disease among more than 2,000 Greek adults over a 10-year period, beginning in 2002. Participants were asked to complete a detailed food frequency survey at the time of enrollment, after five years and after 10 years.

At the end of the study period, researchers analyzed the relationship between diet and the development of cardiovascular disease using a dietary index that divided participants into three groups based on the number of animal-based foods (which included meats as well as animal-derived products such as eggs and dairy) they consumed per day. Overall, men eating fewer animal-based foods were 25% less likely to develop heart disease compared to men eating more animal-based foods. The same overall trend was seen in women, but the relationship was less strong, with an overall risk reduction of about 11% among women eating the fewest animal-based foods.

Even though the difference in cardiovascular disease risk was significant between these groups, the overall difference in consumption of animal-based foods was relatively small. Those following a more plant-based diet consumed, on average, three animal-based foods daily while those following a less plant-based diet consumed five.

"These findings highlight that even a small reduction in the daily consumption of animal-based products -- principally the less healthy foods, such as processed meat products -- accompanied by an increase in healthy plant-based foods may contribute to better cardiovascular health," Panagiotakos said.

Focusing in on participants who followed a more plant-based diet, researchers then categorized each participant's diet as either healthful (reflecting increased consumption of fruits, vegetables, whole grains, nuts, legumes, oils and tea or coffee) or unhealthful (reflecting increased consumption of juices,

sweetened beverages, refined grains, potatoes and sweets). Only participants following a healthful plant-based diet had a significant reduction in cardiovascular risk compared to those who ate more animal-based products.

Differences in eating patterns -- and associated cardiovascular risk reduction -- were also observed between women and men. In general, men ate about three times per day while women tended to snack more, eating four to five times daily. At the same time, women showed a more dramatic increase in heart disease risk when eating an unhealthful plant-based diet and a more dramatic reduction in risk when eating a healthful plant-based diet compared to men who fell into the same two categories. This suggests that snacking on healthful foods can be beneficial while snacking on unhealthful foods can bring higher risks, Panagiotakos said.

The study was limited by its reliance on questionnaires to track participants' diets. However, the findings bolster evidence for the heart health benefits of a plant-based diet and could help inform future dietary guidance for prevention of cardiovascular disease.

"In the future, I believe it will be useful if cardiovascular disease prevention guidelines offer clearer and specific nutrition suggestions, in terms of the types of foods that are recommended and the portions that should be consumed," Panagiotakos said.

https://www.sciencedaily.com/releases/2020/03/200318104449.htm

Daily avocado consumption improves attention in persons with overweight, obesity

March 10, 2020

Science Daily/University of Illinois at Urbana-Champaign, News Bureau

A diet including daily avocado consumption improves the ability to focus attention in adults whose measurements of height and weight are categorized as overweight or obese, a new randomized control trial found.

Researchers at the University of Illinois at Urbana-Champaign conducted the 12-week study, published in the International Journal of Psychophysiology.

"Previous work has shown that individuals with overweight and obesity are at higher risk for cognitive decline and dementia in older age," said kinesiology and community health professor Naiman Khan, who led the study. "We are interested in whether dietary approaches may have benefits for cognitive health, especially in midlife."

The Hass Avocado Board and the U.S. Department of Agriculture's National Institute of Food and Agriculture supported this work.

Avocados are high in lutein, a dietary component associated with cognitive benefits. Though avocado consumption's benefits have been studied in older adults and children, no randomized controlled trials had studied its cognitive effects on adults with overweight or obesity, despite 70% of the American adult population falling into that category, said graduate student Caitlyn Edwards, the first author of the study.

In the new study, the researchers provided 12 weeks of daily meals to 84 adults with overweight or obesity. The meals were identical in calories and macronutrients, but one group's meals included a fresh avocado every day, while the control group had no avocado in their meals.

At the beginning and end of the study, the participants completed three cognitive tests to measure attention and inhibition. In addition, the researchers measured lutein levels in the participants' serum and in their retinas, which is associated with the lutein concentration in the brain.

They found that the participants whose diets included avocados improved their performance on one of the cognitive tests, called the Flanker task, which measures attentional inhibition -- the ability to maintain focus on the task at hand even in the face of distraction. However, there was no difference in the other two cognitive tests.

"It could be that nutrients in avocados have a specific action in the brain that supports the ability to do this task in particular, or they could be more beneficial for certain cognitive abilities over others," Khan said. "It's also possible that with a longer study or different tests, we could see other effects. Other studies have found broader effects in other populations, so it is interesting to see a more specific benefit for this population."

Another unexpected finding was that, while the participants who ate avocados had higher levels of lutein at the end of the study, the changes in lutein levels were not correlated with their cognitive changes.

"Avocados also are high in fiber and monounsaturated fats. It is possible that these other nutrients may have played a role in the cognitive effects we saw, but we focused on the lutein in our analyses," Edwards said. "Future analyses may focus on other nutrients found in avocados, or avocado consumption's impact on other measures such as weight status, inflammation and potential changes in the microbiome."

Although this study focused on avocados, other dietary sources of lutein, fiber and unsaturated fats -- such as green leafy vegetables or eggs -- also have potential cognitive and health benefits. The researchers say their study shows that small dietary changes, such as eating avocados, can have measurable impacts on cognitive performance, even when other health behaviors remain the same.

"Our mission is to give people options. There are multiple ways people can eat to optimize brain health," Khan said. "What we're learning is that avocados may be one of those fruits that may be neuroprotective in certain ways. This work provides some evidence behind one option people have from a plethora of healthful foods that we can consume."

https://www.sciencedaily.com/releases/2020/03/200310124711.htm

Implicit bias against women: Men more likely than women to be seen as brilliant

New global study finds an unconscious stereotype linked to gender

July 2, 2020

Science Daily/New York University

Men are more likely than are women to be seen as "brilliant," finds a new study measuring global perceptions linked to gender. The work concludes that these stereotyped views are an instance of implicit bias, revealing automatic associations that people cannot, or at least do not, report holding when asked directly.

The research, which appears in the Journal of Experimental Social Psychology, was conducted by scientists at New York University, the University of Denver, and Harvard University.

"Stereotypes that portray brilliance as a male trait are likely to hold women back across a wide range of prestigious careers," observes Daniel Storage, an assistant professor in the University of Denver's Department of Psychology and the paper's lead author.

"Understanding the prevalence and magnitude of this gender-brilliance stereotype can inform future efforts to increase gender equity in career outcomes," adds Andrei Cimpian, an associate professor in NYU's Department of Psychology and the paper's senior author.

Previous work by Cimpian and his colleagues has suggested that women are underrepresented in careers where success is perceived to depend on high levels of intellectual ability (e.g., brilliance, genius), including those in science and technology.

Less understood are the factors that explain this phenomenon. To address this, the new Journal of Experimental Social Psychologystudy explored the potential impact of stereotypes. For example, perhaps the qualities of genius and brilliance are associated in people's minds with men more than with women -- and, as a result, women are less encouraged to pursue these fields -- or the atmosphere of these fields is less welcoming to women.

However, accurately measuring stereotyping is a challenge. People are often reluctant to admit they have stereotypes, so asking directly about these beliefs is unlikely to provide an accurate measure of whether they endorse the idea that brilliance is more common among men than it is among women.

To overcome this methodological obstacle, the researchers adopted a test that is geared to measure stereotyping indirectly. Here, the aim is to capture implicit stereotypes -- or the automatic associations that come to mind between certain traits (e.g., brilliance) and certain groups (e.g., men). This is in contrast to explicit stereotyping, in which we knowingly and verbally ascribe traits to groups of people.

The team employed a long-established tool, the Implicit Association Test (IAT), which measures the degree of overlap between concepts (e.g., brilliant and male) without explicitly asking subjects whether or not they hold stereotyped views.

The IAT is essentially a speeded sorting task. In the study, participants saw a series of stimuli (such as a picture of a woman or the word "brilliant") on a computer screen and were asked to sort them into two categories by pressing either the E or the I key on their keyboard. For example, in some trials participants were asked to press E if they saw a stimulus that is related to either the category male or the trait brilliant. On other trials, the sorting rule was different. For example, the gender categories were swapped such that participants had to press E if they saw a stimulus that is related to either the category female or the trait brilliant.

The logic of the IAT, the authors explain, is as follows: If brilliant is more associated with male than with female in people's minds, then participants will be faster to sort the stimuli when brilliant and male are paired with the same response key -- because the stereotype makes these two concepts seem like they "go together" -- than when brilliant and female are paired.

Across a series of five studies, which included U.S. women and men, U.S. girls and boys (ages 9 and 10), and women and men from 78 other countries, the researchers consistently found evidence for an implicit stereotype associating brilliance with men more than with women. The magnitude of this stereotype was striking as well -- for example, it was similar in strength to the implicit stereotype that associates men more than women with careers (and women more than men with the family), which was identified in earlier work.

The team also gauged explicit stereotypes, directly asking subjects whether they believed that men are more brilliant than women. In marked contrast to the implicit stereotyping measures, subjects reported disagreeing with this idea -- and, in one study, explicitly associated the quality of being "super smart" with women more than with men. The finding is consistent with previous scholarship showing that people are unlikely admit to stereotyping, reinforcing the importance of measuring such perceptions through more subtle means.

Tessa Charlesworth, a doctoral student at Harvard University and co-author of the paper, notes that "a particularly exciting finding from this work is that, if anything, people explicitly say that they associate women with brilliance. Yet implicit measures reveal a different story about the more automatic gender stereotypes that come to mind when thinking about brilliance."

https://www.sciencedaily.com/releases/2020/07/200702100533.htm

Does 'mommy brain' last? Study shows motherhood does not diminish attention

June 23, 2020

Science Daily/Purdue University

"Mommy brain" is a long-held perception that mothers are more forgetful and less attentive.

"In most studies, however, attention and memory tests are given to mothers very early postpartum," said Valerie Tucker Miller, a Ph.D. student in Purdue University's Department of Anthropology department. Miller is studying the effects of motherhood on attention, memory and other psychological processes.

"There are few issues with that," she added. "When you first have a child, you have a cascade of hormones and sleep deprivation that might be affecting attention and memory processes in the brain."

In a new study testing the prevalence of "mommy brain," Miller used a revised version of the Attention Network Test (ANT), called the ANT-R, to compare reaction times among 60 mothers, all of whom were at least one year postpartum, and 70 non-mothers. The results, published online in the journal Current Psychology, show that mothers performed equally as well or better compared with women who had never been pregnant or had children.

"For this particular study, we recruited moms who were past that first year postpartum because we wanted to see the long-term effects of maternity," she said. "Overall, moms did not have significantly different attention than non-mothers, so we did not find evidence to support 'mommy brain' as our culture understands it. It's possible, if anything, that maternity is related to improved, rather than diminished, attentiveness."

Co-author Amanda Veile, an assistant professor of anthropology at Purdue, said the mixed-method study may be the first to investigate the long-term effects of biological motherhood on real-life attention network functioning. Lisa A. VanWormer, a Purdue University alumna and visiting associate professor of psychology at St. Norbert College, also is a co-author.

Researchers used a seven-point scale to measure participants' responses to survey questions such as, "How sleepy do you feel?" and "How do you think your attentiveness is?" Women's perceived attention functioning was strongly associated with their tested attention scores, regardless of motherhood status, Veile said.

"This means that women have accurate awareness of their cognitive state, and that their concerns regarding their perceived attentional functioning should be taken seriously," she said. "We also believe that 'mommy-brain' may be a culture-bound phenomenon, and that mothers will feel the most distracted and forgetful when they feel stressed, overextended and unsupported. Unfortunately, many U.S. moms feel this way, especially now in the midst of economic and political instability and pandemic."

During the computer test, a cue box flashes for 100 milliseconds in one of two possible locations where a target image will appear on the screen. Next, an image of five arrows, each pointing left or right in consistent or conflicting directions, flashes on the screen for 500 milliseconds. Participants are then asked to press a button that corresponds to the direction of only the middle arrow.

Miller said the test measures response times and provides scores for the three main networks of attention: The alerting network helps the brain prepare for incoming stimuli; the orienting network directs the brain's attention to something new; and the executive control network helps resolve conflicting information.

Mothers in the study were, on average, 10 years older than non-mothers. Even after controlling for age, however, the researchers found that mothers had similar alerting and orienting attention, and better executive control attention, compared to non-mothers.

"Moms were not as distracted by those outside, incongruent items," Miller said. "It makes perfect sense that moms who have brought children into this world have more stimuli that needs to be processed to keep themselves and other humans alive, and then to continue with all the other tasks that were required before the children."

Heightened attention isn't always a good thing. It could become amplified with feelings of stress and isolation, which many U.S. moms experience, causing them to develop anxiety, Veile said.

"We plan to do cross-cultural investigations to further examine how narratives of motherhood and social support are associated with maternal tested attention and well-being around the world," she said.

https://www.sciencedaily.com/releases/2020/06/200623145352.htm

Early-life education improves memory in old age -- Especially for women

June 5, 2020

Science Daily/Georgetown University Medical Center

Education appears to protect older adults, especially women, against memory loss, according to a study by investigators at Georgetown University Medical Center, published in the journal Aging, Neuropsychology, and Cognition.

The results suggest that children -- especially girls -- who attend school for longer will have better memory abilities in old age. This may have implications for memory loss in Alzheimer's disease and other dementias.

The study tested declarative memory in 704 older adults (58-98 years of age). Declarative memory refers to our ability to remember events, facts, and words, such as where you put your keys or the name of that new neighbor.

Participants were shown drawings of objects, and then were tested several minutes later on their memory of these objects. The investigators found that their memory performance became progressively worse with aging. However, more years of early-life education countered these losses, especially in women.

In men, the memory gains associated with each year of education were two times larger than the losses experienced during each year of aging. However, in women, the gains were five times larger.

For example, the declarative memory abilities of an 80-year-old woman with a bachelor's degree would be as good as those of a 60-year-old woman with a high school education. So, four extra years of education make up for the memory losses from 20 years of aging.

"Simply said, learning begets learning" says the study's senior investigator, Michael Ullman, PhD, a professor in Georgetown's Department of Neuroscience and Director of the Brain and Language Lab. Ullman's research on the relationship between language, memory and the brain has been a cornerstone in the fields of language and cognitive neuroscience.

"Since learning new information in declarative memory is easier if it is related to knowledge we already have, more knowledge from more education should result in better memory abilities, even years later," adds the study's lead author, Jana Reifegerste, PhD, a member of the scientific staff at the University of Potsdam, Germany, who worked on this study as a postdoctoral researcher in Ullman's lab.

"Evidence suggests that girls often have better declarative memory than boys, so education may lead to greater knowledge gains in girls," says Ullman. "Education may thus particularly benefit memory abilities in women, even years later in old age."

The study tested individuals in a non-Western (Taiwanese) population. Participants varied in the number of years of education, from none at all to graduate studies. Future research is needed to test whether the findings generalize to other populations, Ullman says.

"These findings may be important, especially considering the rapidly aging population globally," Reifegerste says. "The results argue for further efforts to increase access to education."

"Education has also been found to delay the onset of Alzheimer's disease," Ullman says. "We believe that our findings may shed light on why this occurs."

https://www.sciencedaily.com/releases/2020/06/200605003035.htm

Exposure to 'good bacteria' during pregnancy buffers risk of autism-like syndrome

Study in rats suggests prenatal microbial exposures influence neurodevelopment

May 27, 2020

Science Daily/University of Colorado at Boulder

Giving beneficial bacteria to stressed mothers during the equivalent of the third trimester of pregnancy prevents an autism-like disorder in their offspring, according to a new animal study by University of Colorado Boulder researchers.

The study, published in the journal Brain, Behavior, and Immunity, marks the latest in a series of studies in animals and humans suggesting that exposure to certain immune-modulating microbes can dampen inflammation, positively impacting the brain and central nervous system.

It's among the first studies to suggest that such exposures during pregnancy influence neurodevelopment of a fetus and, while far more research is necessary, could open the door to new prenatal interventions.

"It suggests that you could develop microbial interventions that lower the risk of neurodevelopmental syndromes like autism," said co-author Christopher Lowry, an associate professor in the Department of Integrative Physiology.

In humans, research has long shown that maternal stress during pregnancy prompts systemic inflammation in both the mother and fetus and is a risk factor for autism, said senior author Daniel Barth, a professor of psychology and neuroscience.

In a previous study, Barth found that when rats were stressed and given a drug called terbutaline, which is often administered to women to delay preterm labor, their offspring demonstrated an autism-like syndrome -- including the two hallmark features of social deficits and repetitive behavior. They also developed an epilepsy-like seizure disorder.

"Our fundamental question with this new study was whether we could use an immunoregulatory microbe to prevent the long-term consequences of environmental stressors during pregnancy," said first author Zachariah Smith, a post-doctoral researcher in Barth's lab.

For the study, the researchers exposed rats to mild stressors and gave them terbutaline during what would be the equivalent of the third trimester of pregnancy in humans.

Half were also given a series of injections of a heat-killed preparation of a friendly bacterium known as Mycobacterium vaccae (M. vaccae), shown in previous studies to have lasting anti-inflammatory effects on the brain. A third control group of rats got no treatments.

At two and four months, the pups were given a series of tests assessing, among other things, their degree of social interaction and whether they exhibited repetitive behaviors.

As in the previous study, those whose mothers had been stressed and given terbutaline showed autism-like behaviors. But those who had been immunized with M. vaccae did not.

"Immunization with M. vaccae appears to provide some protection against the negative effects of environmental stressors during development, specifically against Autism Spectrum Disorder (ASD)-like behavior," said Smith.

The inoculation did not appear to protect against development of seizure disorders. But because epilepsy tends to develop later in life, the researchers intend to repeat the experiment with a larger sample size and longer treatment period.

Autism and epilepsy often manifest together in humans, with about 30% of autistic individuals exhibiting epileptic symptoms, such as seizures. Stress-induced inflammation likely plays a role in both, the researchers suspect.

"It could be that if we continue the treatment for longer we could also prevent the development of some cases of epilepsy, but much more research is necessary," said Lowry.

The researchers caution that they are not developing an "autism vaccine" and they are not suggesting that microbial interventions could reverse the disorder in children who already have it. But their study does reinforce the idea that exposure to beneficial microorganisms, sometimes referred to as "old friends," can play a critical role in brain development in utero.

Ultimately, Lowry envisions a day when stressed moms deemed particularly high risk of having a child with a neurodevelopmental disorder could be given a specially formulated probiotic or inoculation to support healthy brain development of their child.

"This is the first maternal intervention that I know of that has been able to prevent an autism-like syndrome, including the behavioral and social aspects," Lowry said. "If this could be replicated in humans, that would be pretty profound."

Meantime, they say, mothers should be cognizant of the potential risks of emotional and environmental stressors, including the drug terbutaline, during pregnancy.

And they should try to expose themselves to beneficial bacteria, through fermented foods like yogurt and sauerkraut and even time spent in nature.

https://www.sciencedaily.com/releases/2020/05/200526173818.htm

Women's heart attack symptoms are not all that different

May 4, 2020

Science Daily/European Society of Cardiology

The top three heart attack symptoms in both women and men are chest pain, sweating, and shortness of breath, reports a study presented today on EAPC Essentials 4 You, a scientific platform of the European Society of Cardiology (ESC), and published in the Journal of the American Heart Association.

"Heart attack symptoms are often labelled as 'typical' in men and 'atypical' in women," said study author Dr. Annemarijn de Boer of the University Medical Centre Utrecht, the Netherlands. "But our study shows that while symptoms can differ between the sexes, there are also many similarities."

Whatever your gender, if you experience heart attack symptoms, don't delay. Call the emergency services immediately.

Symptom recognition is crucial to enable fast, live saving treatment for people having a heart attack. Some previous studies report sex differences in symptoms while others report shared symptoms.

This study compiled the highest quality studies -- 27 in total -- from the past two decades detailing symptoms in patients with confirmed acute coronary syndrome (heart attack or unstable angina).

In addition to sharing the three most common symptoms, the majority of men and women experiencing an acute coronary syndrome had chest pain: 79% of men and 74% of women.

Significant differences in symptom presentation between women and men were also reported. Compared to men, women were more than twice as likely to have pain between the shoulder blades, 64% more likely to have nausea or vomiting, and 34% more likely to experience shortness of breath. Although chest pain and sweating were the most frequent symptoms in both women and men, they occurred less often in women, who had a 30% lower odds of chest pain and 26% lower odds of sweating compared to men.

The study did not investigate the reasons why there are some variations in symptom presentation between women and men, but Dr. de Boer said: "Previous research has shown sex differences in how heart attacks occur in the body, but it is uncertain how or whether this relates to symptom presentation. The cause of symptom differences between the sexes deserves further study."

https://www.sciencedaily.com/releases/2020/05/200504083055.htm

Women's lifestyle changes, even in middle age, may reduce future stroke risk

April 9, 2020

Science Daily/American Heart Association

Middle age may not be too late for women to substantially reduce their stroke risk by not smoking, exercising, maintaining a healthy weight and making healthy food choices, according to new research published today in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.

In general, women are more likely than men to have a stroke, die from stroke and have poorer health and physical function after a stroke. The average age of first stroke in women is 75 years. Based on this information, researchers theorized that making mid-life lifestyle changes might help reduce stroke's burden among women.

"We found that changing to a healthy lifestyle, even in your 50s, still has the potential to prevent strokes," said Goodarz Danaei, Sc.D., lead study author and Bernard Lown Associate Professor of Cardiovascular Health at Harvard T.H. Chan School of Public Health in Boston. "Women who made lifestyle modifications in middle age reduced their long-term risk of total stroke by nearly a quarter and ischemic stroke, the most common type of stroke, by more than one-third."

Researchers analyzed the Nurses' Health Study, which includes health information on nearly 60,000 women who enrolled at average age of 52 and continued in the study for an average of 26 years. Researchers studied the impact on stroke risk from smoking cessation, exercising 30 minutes or more daily and gradual weight loss if women were overweight. The researchers also studied the impact of making recommended dietary modifications that emphasize eating more fish, nuts, whole grains, fruits and vegetables and less red meat, no processed meat and less alcohol.

During the 26-year follow-up, researchers found:

• 4.7% of women with no lifestyle interventions had a stroke of any type; 2.4% had ischemic stroke; and 0.7% had hemorrhagic stroke.

• Engaging in the three non-dietary interventions -- smoking cessation, daily exercise and weight loss -- was estimated to reduce the risk of total stroke by 25% and ischemic stroke by 36%.

• Sustained dietary modifications were estimated to reduce the risk of total stroke by 23%.

Researchers also found that increasing fish and nut consumption and reducing unprocessed red meat consumption appeared to have positive impacts on reducing stroke risk, although the degree of impact from these dietary changes was not as big as those achieved through increased physical activity, smoking cessation and maintaining a healthy weight.

While this was an observational study that included mostly white, middle-aged women, Danaei said, "there are other studies to support that the proportional changes in stroke risk from lifestyle and dietary modifications may be generalizable to men. We also estimate that exercising 30 minutes or more daily may reduce the risk of stroke by 20%."

https://www.sciencedaily.com/releases/2020/04/200409085637.htm

Babies retain even detailed events during a nap

During sleep, toddlers' brains consolidate details without generalizing them

April 7, 2020

Science Daily/Max Planck Institute for Human Cognitive and Brain Sciences

While sleeping the brain goes through previously experienced things, consolidates new memory contents and summarizes similar experiences into more general knowledge. This also applies to babies. However, they can more than just generalize what they have learned. A recent study shows: during sleep a baby's brain also consolidates the details of its individual experience and protects them from generalization and is therefore also important for what is known as episodic memory.

The brain is permanently exposed to new impressions. Even when sleeping, it does not rest and processes recent experiences. In very early childhood, it has been thought that sleep primarily promotes semantic memory. This includes general knowledge such as the meaning of words. However, scientists at the Max Planck Institute for Human Cognitive and Brain Sciences (MPI CBS) Leipzig and the Humboldt University (HU) Berlin, together with researchers from Lübeck and Tübingen, have now shown for the first time in their study published in Nature Communications that babies also build their episodic memory when they nap. This enables them to remember the details of their individual experiences after napping.

The scientists examined this relationship using a three-phase study. During the learning phase, the 14 to 17-month-old children were shown pictures of objects whose names they already knew, containing different cars, balls or dogs. They then heard the appropriate name for each picture. One group of the children spent the following one to two hours sleeping, while a second group stayed awake. In the subsequent test phase, the researchers showed the young participants different pictures again, including those that they had already seen in the learning phase as well as new cars, balls and dogs. Each object was once named correctly and once incorrectly. During all phases of the experiment, the researchers recorded the baby's brain activity using the electroencephalogram (EEG).

The analysis of the EEG activity made it clear: The brain of the children who had slept responded differently in the memory test than that of those who stayed awake -- but only in certain cases. If the researchers presented the babies with a ball that they had never seen before and called it a car, the brain responses initially did not differ. In both groups, the so-called N400 component appeared, which occurs when the brain processes inappropriate meanings. The children obviously knew that a ball is not a car.

It was different, however, when the babies viewed a ball from the learning phase and it was called a car. The group that had stayed awake again showed the N400 component, while the group that had slept did not. In the children who had napped, the researchers observed a brain response that was triggered when a ball from the learning phase was again correctly named as such. However, this response did not occur when a new ball was called a ball. The researchers concluded: After sleep, the babies no longer understood the object-word pairs they had previously experienced as naming a meaning. Rather, they recognized them as individual episodes. Object and word were thus merged into a unified event in the memory.

"The results show that sleep not only enables the infant brain to generalize individual experiences, but also to preserve individual experiences in detail and to differentiate them from existing general knowledge," explains first author Manuela Friedrich, researcher at the MPI CBS and HU Berlin. She further hypothesizes: "The fact that a recognized object-word episode is not understood as referring to general knowledge means that its details can be protected from mixing with existing memory."

The results are also interesting with respect to the so-called infantile amnesia, i.e. the phenomenon of not being able to remember one's own early childhood experiences. It has often been assumed that very young children are not yet capable of forming longer-term episodic knowledge. However, the current findings clearly show that even babies can remember events in detail -- and sleep contributes significantly to this.

https://www.sciencedaily.com/releases/2020/04/200407131435.htm

Consuming extra calories can help exercising women avoid menstrual disorders

March 31, 2020

Science Daily/The Endocrine Society

Exercising women who struggle to consume enough calories and have menstrual disorders can simply increase their food intake to recover their menstrual cycle, according to a study accepted for presentation at ENDO 2020, the Endocrine Society's annual meeting, and publication in the Journal of the Endocrine Society.

The study found that exercising women with menstrual disorders can start menstruating again by consuming an additional 300-400 calories a day.

"These findings can impact all exercising women, because many women strive to exercise for competitive and health-related reasons but may not be getting enough calories to support their exercise," said lead researcher Mary Jane De Souza, Ph.D., of Penn State University.

By consuming enough calories, exercising women with menstrual disorders can avoid complications associated with a condition known as the Female Athlete Triad, De Souza said. This is a medical condition that starts with inadequate food intake that fails to meet the body's needs. It leads to menstrual disorders and poor bone health. It is associated with a high incidence of stress fractures.

The study included 62 young, exercising women with infrequent menstrual periods. Thirty-two women increased their calorie intake an average of 300-400 calories a day, and 30 maintained their exercise and eating habits for the 12-month study. Women who consumed the extra calories were twice as likely to have their menstrual period during the study compared with the women who maintained their regular exercise and eating routine.

"This strategy is easy to implement with the help of a nutritionist. It does not require a prescription and avoids complications from drug therapy," De Souza said. "The findings will encourage healthcare providers to try to help exercising women with menstrual disorders who consume too few calories to eat more, and this may help them to be healthier athletes and avoid bone complications."

https://www.sciencedaily.com/releases/2020/03/200331093259.htm

Mother/infant skin-to-skin touch boosts baby's brain development and function

Both mother and baby physiology respond to kangaroo care method

March 25, 2020

Science Daily/Florida Atlantic University

As the world prioritizes social distancing to stop or slow down the spread of coronavirus (COVID-19), a new study by researchers at Florida Atlantic University demonstrates that mother-infant touch and contact are essential for optimal neurodevelopmental regulation in early infancy. Kangaroo Care, a skin-to-skin, chest-to-chest method of caring for a baby, especially one who is premature, has been associated with promoting neurophysiological development. This method of caring emphasizes the importance of holding the naked or partially dressed baby against the bare skin of a parent, typically the mother. New research is showing that extended use of Kangaroo Care can positively benefit full-term infants and their mothers during the post-partum period.

The longitudinal randomized, controlled trial investigated if Kangaroo Care influences markers of neuro-maturation in healthy, full-term infants. They focused on the potential association between Kangaroo Care and infant brain development, specifically measures of EEG (electroencephalogram) asymmetry/power and coherence.

In addition to EEG patterns in infants, the researchers looked at basal oxytocin -- the "cuddle" hormone -- and cortisol reactivity -- the "stress" hormone -- in infants and their mothers. Oxytocin is considered an affiliative hormone associated with caregiving and affectionate behavior whereas cortisol reactivity is implicated in the stress response system. Researchers compared six weeks of Kangaroo Care to standard caring (control group) during the first three months of life.

For the study, mothers assigned to the Kangaroo Care group were given a Kangaroo Care wrap (Nurtured by Design, The Kangaroo Zak) and were taught proper procedures by a certified trainer at the prenatal visit. Mothers were asked to use Kangaroo Care, skin-to-skin, chest-to-chest contact with her infant, for one hour a day for six weeks and were provided with journals to record the frequency of Kangaroo Care use. Mothers in the control group were given infant feeding pillows and journals and were asked to record infant feedings for six weeks. Babies were fitted with a stretch Lycra cap to measure EEG activity during a five-minute quiet-alert state at three-months. Oxytocin was measured by collecting maternal and infant urine, and infant cortisol reactivity was measured by collecting infant saliva samples before and after a mild stressor.

Results of the study, published in the journal Infant Behavior and Development, provide evidence that the physiology of mothers and their full-term infants is influenced by obtaining Kangaroo Care training and utilizing it during the post-partum period.

"We wanted to know if exposure to extended tactile stimulation using the Kangaroo Care method would increase peripheral basal oxytocin and suppress cortisol reactivity in the babies in our study," said Nancy Aaron Jones, Ph.D., senior author, an associate professor, and director of the FAU WAVES Emotion Laboratory in the Department of Psychology in FAU's Charles E. Schmidt College of Science, and a member of the FAU Brain Institute (I-BRAIN). "We also wanted to examine if Kangaroo Care increases oxytocin levels in mothers, which has important implications for post-partum depression."

Findings showed that the infants' left frontal area of the brain (implicated in higher-order cognitive and emotional regulatory skills) appears to be stimulated from the Kangaroo Care method. In addition, mother/infant dyads showed increased oxytocin along with decreases in stress reactivity, suggesting regulatory abilities are prompted by experiences with positive caregiving in infancy.

Results from the study indicate that Kangaroo Care training and level of use by caregivers during infancy can favorably influence both neurodevelopmental trajectories and infant neurobiological functioning.

"Our findings across several studies demonstrate a link between the supportive dimensions of maternal caregiving behavior and left hemisphere neurodevelopment, with maternal warmth and sensitivity predicting greater regulatory abilities and secure attachment," said Jones. "Full-term infants and their mothers likely benefit from the positive interactive experiences inherent in extended Kangaroo Care use."

https://www.sciencedaily.com/releases/2020/03/200325110913.htm