Hypertensive pregnancy disorders linked to future cardiac events

May 9, 2022

Science Daily/NIH/National Heart, Lung and Blood Institute

Women who experienced complications related to developing high blood pressure, or hypertension, during pregnancy had a 63% increased risk for developing cardiovascular disease later in life, according to research funded by the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health.

While hypertensive pregnancy complications previously have been linked to increased cardiovascular risks, the current study controlled for pre-pregnancy shared risk factors for these types of complications and cardiovascular disease. Researchers also found that high blood pressure, high cholesterol, type 2 diabetes, or being overweight or obese after pregnancy accounted for most of the increased risk between pregnancy complications and future cardiovascular events.

The findings, published in the Journal of the American College of Cardiology, could support healthcare providers in developing personalized heart disease prevention and monitoring strategies for women who had hypertension during pregnancy. The information could also help bridge the gap that often occurs after a woman ends obstetric care and resumes or starts care with another provider.

Using health data shared by more than 60,000 participants in the Nurses' Health Study II, the research represents one of the most comprehensive reviews evaluating links between future cardiovascular events in women who have had preeclampsia or gestational hypertension. Gestational hypertension is characterized by an increase in blood pressure during pregnancy. Preeclampsia is a more severe complication marked by a sudden rise in blood pressure that can affect the organs and be dangerous for both mother and baby. Both conditions are often diagnosed after 20 weeks of pregnancy.

"Women with a history of gestational hypertension or preeclampsia should be informed that they have an increased risk for cardiovascular disease," said Jennifer J. Stuart, Sc.D., a study author and associate epidemiologist in the Division of Women's Health at Brigham and Women's Hospital and Harvard Medical School, Boston. "While the American Heart Association and American College of Cardiology recognize these conditions as cardiovascular risk factors, women and their providers have lacked clear direction on what to do in the intervening years between delivery of a hypertensive pregnancy and the onset of cardiovascular disease."

The researchers' analysis showed that early screening and monitoring in four targeted areas -- blood pressure, cholesterol and glucose levels, and body mass index -- could provide even more personalized targets to help delay or possibly prevent future cardiovascular events among these women.

In this study, almost 10% of women developed hypertension during their first pregnancy. Among these women, 3,834 (6.4%) developed preeclampsia and 1,789 (3%) developed gestational hypertension. Women who were obese before pregnancy were three times more likely to experience a hypertensive pregnancy disorder, and those with a family history of heart disease or stroke also shared increased risks. In their analysis, the researchers controlled for these and other important pre-pregnancy factors that could increase the risk of developing hypertension during pregnancy and having a heart attack or stroke later in life.

After about 30 years, when the average age of women in the study was 61 years, approximately 1,074 (1.8%) of study participants had experienced a cardiovascular event, such as a heart attack or stroke. The type of event women had -- and when they had it -- often overlapped with specific pregnancy complications.

For example, compared to women with normal blood pressure in pregnancy, women with gestational hypertension, which was associated with a 41% increased risk for cardiovascular disease, were more likely to have a stroke about 30 years after their first pregnancy. Women with preeclampsia, which was associated with a 72% increased cardiovascular risk, were more likely to have a coronary artery event, such as a heart attack, as early as 10 years after their first pregnancy.

Post-pregnancy cardiometabolic risk factors, such as obesity, type 2 diabetes, and chronic hypertension, explained most of the increased cardiovascular risk observed among women with gestational hypertension or preeclampsia. Chronic hypertension was the largest contributor of all, accounting for 81% of increased cardiovascular disease risks among women who had gestational hypertension and for 48% of increased risks among women who had preeclampsia. Most women who experienced a hypertensive pregnancy disorder developed chronic hypertension in the years or decades after they gave birth.

"This study reinforces how important it is for women and their healthcare providers to address known cardiovascular disease risk factors, such as obesity or having high blood pressure, while thinking about starting a family and then during and after during pregnancy," said Victoria Pemberton, R.N.C., a program officer at NHLBI.

For future research, Stuart said diversity is key. Most women in the Nurses' Health Study II were white, which means the percentage of women affected by different risk factors may vary. The study also provides a foundation to expand on emerging associations, such as studying links between gestational hypertension and stroke and between preeclampsia and coronary artery disease.

Additionally, while over 80% of the increased risk for cardiovascular disease among women with a history of gestational hypertension appears to be jointly accounted for by established cardiovascular risk factors, nearly 40% of the risk for cardiovascular disease following preeclampsia remains unexplained.

Investigating these pathways may help clarify why some women who experienced preeclampsia are more likely to develop heart disease. By better understanding these connections, researchers may be able to contribute insight to help healthcare providers provide even more personalized recommendations and strategies for women at greatest risk.

https://www.sciencedaily.com/releases/2022/05/220509150748.htm 

Complex human childbirth and cognitive abilities a result of walking upright

May 10, 2022

Science Daily/University of Zurich

Childbirth in humans is much more complex and painful than in great apes. It was long believed that this was a result of humans' larger brains and the narrow dimensions of the mother's pelvis. Researchers have now used 3D simulations to show that childbirth was also a highly complex process in early hominins that gave birth to relatively small-brained newborns -- with important implications for their cognitive development.

During human birth, the fetus typically navigates a tight, convoluted birth canal by flexing and rotating its head at various stages. This complex process comes with a high risk of birth complications, from prolonged labor to stillbirth or maternal death. These complications were long believed to be the result of a conflict between humans adapting to walking upright and our larger brains.

Dilemma between walking upright and larger brains

Bipedalism developed around seven million years ago and dramatically reshaped the hominin pelvis into a real birth canal. Larger brains, however, didn't start to develop until two million years ago, when the earliest species of the genus Homo emerged. The evolutionary solution to the dilemma brought about by these two conflicting evolutionary forces was to give birth to neurologically immature and helpless newborns with relatively small brains -- a condition known as secondary altriciality.

A research group led by Martin Häusler from the Institute of Evolutionary Medicine at the University of Zurich (UZH) and a team headed up by Pierre Frémondière from Aix-Marseille University have now found that australopithecines, who lived about four to two million years ago, had a complex birth pattern compared to great apes. "Because australopithecines such as Lucy had relatively small brain sizes but already displayed morphological adaptations to bipedalism, they are ideal to investigate the effects of these two conflicting evolutionary forces," Häusler says.

Typical ratio of fetal and adult head size

The researchers used three-dimensional computer simulations to develop their findings. Since no fossils of newborn australopithecines are known to exist, they simulated the birth process using different fetal head sizes to take into account the possible range of estimates. Every species has a typical ratio between the brain sizes of its newborns and adults. Based on the ratio of non-human primates and the average brain size of an adult Australopithecus, the researchers calculated a mean neonatal brain size of 180 g. This would correspond to a size of 110 g in humans.

For their 3D simulations, the researchers also took into account the increased pelvic joint mobility during pregnancy and determined a realistic soft tissue thickness. They found that only the 110 g fetal head sizes passed through the pelvic inlet and midplane without difficulty, unlike the 180 g and 145 g sizes. "This means that Australopithecus newborns were neurologically immature and dependent on help, similar to human babies today," Häusler explains.

Prolonged learning key for cognitive and cultural abilities

The findings indicate that australopithecines are likely to have practiced a form of cooperative breeding, even before the genus Homo appeared. Compared to great apes, the brains developed for longer outside the uterus, enabling infants to learn from other members of the group. "This prolonged period of learning is generally considered crucial for the cognitive and cultural development of humans," Häusler says. This conclusion is also supported by the earliest documented stone tools, which date back to 3.3 million years ago -- long before the genus Homo appeared.

https://www.sciencedaily.com/releases/2022/05/220510102920.htm

Stress may be associated with fertility issues in women

Animal study links scream sound exposure to lower egg count in female rats

May 10, 2022

Science Daily/The Endocrine Society

Female rats exposed to a scream sound may have diminished ovarian reserve and reduced fertility, according to a small animal study published in the Endocrine Society's journal, Endocrinology.

Ovarian reserve is the reproductive potential left within a woman's two ovaries based on the number and quality of eggs. A woman is born with a finite number of eggs and her body cannot create any more. Diminished ovarian reserve is the loss of normal reproductive potential in the ovaries due to a lower count or quality of the remaining eggs.

"We examined the effect of stress on ovarian reserve using a scream sound model in rats," said Wenyan Xi, Ph.D., of the Second Affiliation Hospital of Xi'an Jiao Tong University in Xian, China. "We found that female rats exposed to the scream sound had diminished ovarian reserve and decreased fertility."

The researchers used a scream sound model to investigate the effect of stress on ovarian reserve in female rats. They exposed female rats to a scream sound for 3 weeks and analyzed the effect on their sex hormones, the number and quality of their eggs and their ability to get pregnant and have babies after mating.

They found the scream sound decreased the rats' estrogen and Anti-Mullerian hormone levels. Estrogen is a group of hormones that play an important role in growth and reproductive development, and Anti-Mullerian hormone is a hormone made by the ovaries which helps form reproductive organs. The scream sound also lowered the number and quality of the women's eggs and resulted in smaller litters.

"Based on these findings, we suggest stress may be associated with diminished ovarian reserve," Xi said. "It is important to determine an association between chronic stress and ovarian reserve because doing so may expand our appreciation of the limitations of current clinical interventions and provide valuable insight into the cause of diminished ovarian reserve."

Other authors of this study include: Hui Mao, Haoyan Yao and Ruiting Shi of the Second Affiliation Hospital of Xi'an Jiao Tong University; and Zhiwei Cui of the First Affiliation Hospital of Xi'an Jiao Tong University in Xian, China.

The study received funding from the Natural Science Foundation of Shaanxi Provincial Department of Education.

https://www.sciencedaily.com/releases/2022/05/220510102841.htm

Surprising risk factors may predict heart attacks in young women

May 4, 2022

Science Daily/Yale University

A new Yale-led study has for the first time identified which risk factors are more likely to trigger a heart attack or acute myocardial infarction (AMI) for men and women 55 years and younger.

Researchers discovered significant sex differences in risk factors associated with AMI and in the strength of associations among young adults, suggesting the need for a sex-specific preventive strategy. For example, hypertension, diabetes, depression, and poverty had stronger associations with AMI in women compared with men, they found.

The study was published May 3 in JAMA Network Open.

While heart attacks are often associated with older adults, this population-based case-control study examined the relationship between a wide range of AMI-related risk factors among younger adults. The researchers used data from 2,264 AMI patients from the VIRGO (Variation in Recovery: Role of Gender on Outcomes of Young Acute Myocardial Infarction Patients) study and 2,264 population-based controls matched for age, sex, and race from the National Health and Nutrition Examination Survey (NHANES).

The key finding is that young men and women often have different risk factors. Seven risk factors -- including diabetes, depression, hypertension or high blood pressure, current smoking, family history of AMI, low household income, and high cholesterol -- were associated with a greater risk of AMI in women. The highest association was diabetes, followed by current smoking, depression, hypertension, low household income, and family history of AMI. Among men, current smoking and family history of AMI were the leading risk factors.

Rates of AMI in younger women have increased in recent years said Yuan Lu, an assistant professor at Yale School of Medicine and the study's lead author.

"Young women with AMI are an unusual or extreme phenotype on account of their age," she said. "In the past, we found that young women, but not older women, have a twice higher risk of dying after an AMI than similarly aged men. In this new study, we now identified significant differences in risk factor profiles and risk factor associations with AMI by sex."

Analysis of population attributable risk was used to measure the impact different risk factors at the population level. The study found that seven risk factors, many potentially modifiable, collectively accounted for majority of the total risk of AMI in young women (83.9%) and young men (85.1%). Some of these factors -- including hypertension, diabetes, depression, and poverty -- have a larger impact on young woman than they do among young men, Lu and her colleagues found.

"This study speaks to the importance of specifically studying young women suffering heart attacks, a group that has largely been neglected in many studies and yet is about as large as the number of young women diagnosed with breast cancer," said Dr. Harlan M. Krumholz, the Harold H. Hines Jr. Professor of Medicine at Yale, director of the Center for Outcomes Research and Evaluation (CORE), and senior author of the paper.

Raising awareness among physicians and young patients is a first step, researchers said. National initiatives, such as the American Heart Association's "Go Red for Women" campaign, should be expanded to increase awareness about cardiovascular disease risk in young women, they said. Health care providers also need to identify effective strategies to improve optimal delivery of evidence-based guidelines on preventing AMI. For example, risk prediction tool for individual patients could help physicians identify which individuals are most at risk and develop treatment strategies.

Accounting for AMI subtypes may also be effective. The researchers found that many traditional risk factors including hypertension, diabetes, and high cholesterol, are more prevalent in type-1 AMI, whereas different AMI subtypes -- including type-2 AMI (a subtype associated with higher mortality) -- are less common.

"We are moving more towards a precision medicine approach, where we are not treating each patient the same, but recognizing that there are many different subtypes of AMI," Lu said. "Individual-level interventions are needed to maximize health benefits and prevent AMI."

The study is among the first and the largest in the United States to comprehensively evaluate the associations between a wide range of predisposing risk factors and incident AMI in young women and a comparable sample of young men. The study design also included a comparable population-based control group from the National Health and Nutrition Examination Survey, a program to assess demographic, socioeconomic, dietary, and health-related information.

A longitudinal study is traditionally used to assess AMI risk in younger populations. Because the incidence rate is low in young people, however, it takes a long time for the disease to manifest. So researchers often don't have enough AMI events to make inferences about risk factors and their relative importance in young women and men, said Lu.

"Here we used a novel study design with a large cohort of patients with AMI and then we identified age-sex-race matched population control from a national population survey to compare this with, and we used a case-control design to evaluate the association of these risk factors with AMI," said Lu. "This is one of the first and largest studies to address this issue comprehensively."

In the United States, hospitalization rates for heart attacks have been decreasing with time, according to research in the journal JAMA Cardiology.

"However, if you analyze the proportion of these patients by age, you will find that the proportion of younger people who are hospitalized for heart attack is increasing," said Lu. "So it seems there's a general trend for AMI to happen earlier in life, so that makes prevention of heart attack in younger people, especially important."

Younger women represent about 5% of all heart attacks that occur in the U.S. each year. "This small percentage effects a large number of people because so many AMIs occur in the US each year," she said. "There about 40,000 AMI hospitalizations in young women each year, and heart disease is the leading cause of death in this age group."

Lu emphasized the importance of education. "When we talk about heart attack in young women, people are often not aware of it," she said. "If we can prevent women from having heart attacks that will improve outcomes."

Raising awareness about the incidence of heart attacks in younger women is a key part of the strategy, she said. The next frontier of cardiovascular disease prevention in young women could be better understanding the role of women-related factors.

Previous studies have shown that women-related factors may be associated with risk of heart attack, but there is limited data on women under the age of 55. "We hope to explore women-related factors including menopausal history, pregnancy, menstrual cycle, and other factors that are specifically related women and analyze whether that's contributing to the risk of heart attack," she said.

https://www.sciencedaily.com/releases/2022/05/220504130820.htm

Effects of stress on adolescent brain's 'triple network'

Acute stress, repeated traumas shift functional connectivity

May 11, 2022

Science Daily/Elsevier

Stress and trauma during adolescence can lead to long-term health consequences such as psychiatric disorders, which may arise from neurodevelopmental effects on brain circuitry. A new study in Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, published by Elsevier, has used functional magnetic resonance imaging (fMRI) to examine the effects of acute stress and "polyvicitimization," or repeated traumas, on three brain networks in adolescents.

"While negative health outcomes have been associated separately with early life victimization exposure, disrupted adolescent neurodevelopment, and aberrant neural network responses to acute stress, no previous research had examined how these factors are related to each other," explained Rachel Corr, PhD, University of North Carolina at Chapel Hill, NC, USA and lead author of the study. "This study aimed to put together these pieces of the puzzle."

Dr. Corr and colleagues specifically wanted to explore "how acute stress influences functional connectivity of the brain's 'triple networks,'" referring to the default mode network, the salience network, and the central executive network. Together, the three networks are critical for controlling cognition, emotion, perception, and social interaction. Aberrant activity in and between the triple networks has long been associated with psychiatric symptoms.

The researchers analyzed functional connectivity (FC) data previously collected from 79 children aged 9 to 16, many with polyvictimization. To measure the effects of acute stress on brain connectivity, participants completed a task while undergoing fMRI scanning. In the control condition, subjects completed math problems at their own pace and were told their answers were not recorded; in the stress condition, participants had to do the math problems quickly during an allotted time and were given negative feedback about their performance throughout the test.

During the acute stress condition, participants showed altered functional connectivity between the three brain networks. Specifically, the researchers saw increased FC between the default mode and central executive networks, and decreased FC between the salience network and the other two networks. The authors postulate that the insula, a brain region associated with inwardly directed attention, could mediate the changes they saw in FC.

The team also wanted to investigate how the neural network stress response was affected by polyvictimization, in which adolescents may experience multiple forms of victimization, including by parents, peers, or other adults. By studying polyvictimization, they could study the potential cumulative effects of repeated exposures on the brain. Subjects who experienced polyvictimization were more likely to show greater reductions in FC between the salience and default mode networks and the insula in particular. Together the findings suggest that the brain may have adapted to repeated traumas to make it less able to react to stressful experiences. A better understanding of the neurodevelopmental effects of trauma on the brain will help researchers to better address the resulting psychiatric outcomes.

Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging, said of the work, "This study shows how repeated trauma may lead to a maladaptive response to acute stress in important functional brain networks and reveals a potential mechanism by which multiple early life stressors may lead to increased neural vulnerability to stress and the associated liability to future mental health problems."

https://www.sciencedaily.com/releases/2022/05/220511092210.htm

A better diet helps beat depression in young men

May 9, 2022

Science Daily/University of Technology Sydney

Young men with a poor diet saw a significant improvement in their symptoms of depression when they switched to a healthy Mediterranean diet, a new study shows.

Depression is a common mental health condition that affects approximately 1 million Australians each year. It is a significant risk factor for suicide, the leading cause of death in young adults.

The 12-week randomised control trial, conducted by researchers from the University of Technology Sydney, was recently published in the peer-reviewed American Journal of Clinical Nutrition.

Lead researcher Jessica Bayes, a PhD candidate in the UTS Faculty of Health, said the study was the first randomised clinical trial to assess the impact of a Mediterranean diet on the symptoms of depression in young men (aged 18-25).

"We were surprised by how willing the young men were to take on a new diet," Bayes said. "Those assigned to the Mediterranean diet were able to significantly change their original diets, under the guidance of a nutritionist, over a short time frame."

"It suggests that medical doctors and psychologists should consider referring depressed young men to a nutritionist or dietitian as an important component of treating clinical depression," she said.

The study contributes to the emerging field of nutritional psychiatry, which aims to explore the effect that specific nutrients, foods and dietary patterns can have on mental health. The diet used in the study was rich in colourful vegetables, legumes and wholegrains, oily fish, olive oil and raw, unsalted nuts.

"The primary focus was on increasing diet quality with fresh wholefoods while reducing the intake of 'fast' foods, sugar and processed red meat," Bayes said.

"There are lots of reasons why scientifically we think food affects mood. For example, around 90 per cent of serotonin, a chemical that helps us feel happy, is made in our gut by our gut microbes. There is emerging evidence that these microbes can communicate to the brain via the vagus nerve, in what is called the gut-brain axis.

"To have beneficial microbes, we need to feed them fibre, which is found in legumes, fruits and vegetables," she said.

Roughly 30 per cent of depressed patients fail to adequately respond to standard treatments for major depressive disorder such as cognitive behaviour therapy and anti-depressant medications.

"Nearly all our participants stayed with the program, and many were keen to continue the diet once the study ended, which shows how effective, tolerable and worthwhile they found the intervention."

https://www.sciencedaily.com/releases/2022/05/220509112049.htm

Shielding children from food insecurity -- no protection from psychological problems

Large-scale Canadian study also suggests mental health of adults suffers when unable to shield children

May 4, 2022

Science Daily/McGill University

New research found that in families where adults sacrifice their own nutritional needs so that their offspring are fed first, the mental health of both groups is less severely affected, although it is nevertheless affected

It's easy to imagine the emotional distress of both parents and children in families where there isn't enough to eat. Especially if it happens regularly. An increasing number of studies have shown an association between food insecurity and adverse mental health outcomes. Now, new research from McGill University has looked at the impacts of food insecurity on the mental health of both parents and children separately. The researchers found that in families where adults sacrifice their own nutritional needs so that their offspring are fed first, the mental health of both groups is less severely affected. Although it is affected, nevertheless.

The researchers used data from three cycles of the Canadian Community Health Survey (CCHS) between 2007-2018 (with about 100,000 respondents in each cycle, approximately ¼ of whom were children or youth). Because family members responded separately to questions about mental health and well-being, and food security, it was possible to look at how food insecurity affected parents and children differently.

Shielding children from food insecurity has only limited effect on their mental health

"Although it is known that feeding children first protects them from malnutrition, how this practice affects family mental health has been unclear," says Frank Elgar, the senior author on the recent paper in the Canadian Journal of Public Health and a professor in McGill's School of Population and Global Health and the Canada Research Chair in Social Inequalities in Child Health. "We found that, for the one in eight households in Canada that is food-insecure, the ability to shield children and youth was associated onlywith reduced risks of mood disorder in youth, though it was also associated improved mental health outcomes more generally in adults."

There was no evidence to suggest that shielding was associated with a reduction in the risks of anxiety disorder or having poor health or mental health in youth. Shielding aside, the results of the study clearly show that food insecurity is associated with poor mental health and lower well-being in both youth and adults.

"When children and youth are affected by food insecurity during a formative stage in their brain development, even if their parents do their best to shield them, there is no evidence that it significantly improves their psychological outcomes," adds Elgar. "These findings underline the importance of policies that look at food security and mental health at the same time. People at food banks don't just need food, they may also need mental health supports, especially to ensure that children and youth are not affected over the long term."

Detailed findings

• Approximately 84.5 % of the households in the sample were food-secure

• Approximately 15.5 % of the households in the sample were food-insecure to differing degrees (marginal, moderate, or severe)

• The more severe the degree of food insecurity in a household, the lower the level of shielding of youth and children on the part of parents. (Shielding occurred in about 65% of households with marginal food insecurity, 34% of the households with moderate food insecurity, and in just 11% of households with severe food insecurity).

• Approximately 6.3 % of households were food-insecure and shielding youth and children and approximately 9.1 % were food-insecure and not shielding youth.

Comparing youth and adult mental health in food-secure vs. food-insecure households

• Youth and children in food-insecure households where the young were not shielded, showed elevated risks of mood disorder, anxiety disorder, fair or poor mental health, fair or poor general health and low life satisfaction compared to those in food-secure households.

• Youth and children in food-insecure households where the young were shielded, showed elevated risks of only anxiety disorder and fair or poor mental health, and did not differ significantly from youth in food-secure households with respect to other mental health and well-being outcomes.

• Adults in food-insecure households, especially in non-shielding households, showed consistently greater risks of poor mental health and well-being compared with adults in food-secure households.

Comparing youth and adult mental health in shielded vs. unshielded households

• The only significant impact on youth in shielding households compared to unshielded households was a reduced risk of mood disorders. All other mental health risks were similar for youth in shielded and unshielded households.

• Adults had a 22-37% higher risk of their mental health being affected if they were unable to shield their children from food insecurity and showed a greater risk of mood disorders.

"While this study found that shielding children and youth from food insecurity is associated with better psychological outcomes in both adults and youth, further work is needed to isolate the costs and benefits of this protective behaviour," adds Elgar.

https://www.sciencedaily.com/releases/2022/05/220504100943.htm

Humans may have evolved to show signs of stress to evoke support from others

Showing signs of stress could make us more likeable and prompt others to act more positively towards us

May 15, 2022

Science Daily/University of Portsmouth

Showing signs of stress could make us more likeable and prompt others to act more positively towards us, according to a new study by scientists at Nottingham Trent University and the University of Portsmouth.

Researchers examined the paradox of stress behaviour, namely why, as in other primates, humans show signs of stress -- such as scratching, nail-biting, fidgeting, and touching their face or hair -- which could demonstrate to others that they are in weakened state.

They found that, as well as being able to accurately identify when someone was stressed, people reacted more positively towards to the individuals who showed more signs of stress.

As part of the study, participants were videoed while taking part in a mock presentation and interview which they had to prepare with very short notice. The videos were presented to raters, who were asked to rate how stressed they thought the person in the video was.

The participants who reported feeling more stressed during the task were perceived as being more stressed by the raters. Similarly, those showing more self-directed behaviours during the task, such as scratching and nail-biting, were also perceived as more stressed. The findings suggest that people can accurately detect when others are experiencing stress from their behaviours -- something which surprisingly has yet to be shown with scientific evidence.

The participants who were identified as being more stressed during the task, were also perceived as more likeable by others, giving a clue as to why humans have evolved to display stress signals.

Dr Jamie Whitehouse, research fellow at NTU's School of Social Sciences and research lead, said: "We wanted to find out what advantages there might be in signalling stress to others, to help explain why stress behaviours have evolved in humans.

"If producing these behaviours leads to positive social interactions from others who want to help, rather than negative social interactions from those who want to compete with you, then these behaviours are likely to be selected in the evolutionary process. We are a highly cooperative species compared to many other animals, and this could be why behaviours which communicate weakness were able to evolve."

Co-author Professor Bridget Waller added: "If the individuals are inducing an empathetic-like response in the raters, they may appear more likeable because of this, or it could be that an honest signal of weakness may represent an example of benign intent and/or a willingness to engage in a cooperative rather than competitive interaction, something which could be a 'likable' or preferred trait in a social partner. This fits with current understanding of expressivity, which tends to suggest that people who are more "emotionally expressive" are more well-liked by others and have more positive social interactions."

Discussing the next steps, co-author Dr Sophie Milward from the University of Portsmouth added: "Our team is currently investigating whether young children also show this sensitivity to stress states. By looking at childhood we can understand how difficult it is to detect stress, as well as identifying how exposure to adults' stress might impact young children."

https://www.sciencedaily.com/releases/2022/05/220515113229.htm

How sleep helps to process emotions

May 13, 2022

Science Daily/University of Bern

Researchers at the Department of Neurology of the University of Bern and University Hospital Bern identified how the brain triages emotions during dream sleep to consolidate the storage of positive emotions while dampening the consolidation of negative ones. The work expands the importance of sleep in mental health and opens new ways of therapeutic strategies.

Rapid eye movement (REM or paradoxical) sleep is a unique and mysterious sleep state during which most of the dreams occur together with intense emotional contents. How and why these emotions are reactivated is unclear. The prefrontal cortex integrates many of these emotions during wakefulness but appears paradoxically quiescent during REM sleep. "Our goal was to understand the underlying mechanism and the functions of such a surprising phenomenon," says Prof. Antoine Adamantidis from the Department of Biomedical Research (DBMR) at the University of Bern and the Department of Neurology at the Inselspital, University Hospital of Bern.

Processing emotions, particularly distinguishing between danger and safety, is critical for the survival of animals. In humans, excessively negative emotions, such as fear reactions and states of anxiety, lead to pathological states like Post-Traumatic Stress Disorders (PTSD). In Europe, roughly 15% of the population is affected by persistent anxiety and severe mental illness. The research group headed by Antoine Adamantidis is now providing insights into how the brain helps to reinforce positive emotions and weaken strongly negative or traumatic emotions during REM sleep. This study was published in the journal Science.

A Dual mechanism

The researchers first conditioned mice to recognize auditory stimuli associated with safety and others associated with danger (aversive stimuli). The activity of neurons in the brain of mice was then recorded during sleep-wake cycles. In this way, the researchers were able to map different areas of a cell and determine how emotional memories are transformed during REM sleep.

Neurons are composed of a cell body (soma) that integrates information coming from the dendrites (inputs) and send signals to other neurons via their axons (outputs). The results obtained showed that cell somas are kept silent while their dendrites are activated. "This means a decoupling of the two cellular compartments, in other words soma wide asleep and dendrites wide awake," explains Adamantidis. This decoupling is important because the strong activity of the dendrites allows the encoding of both danger and safety emotions, while the inhibitions of the soma completely block the output of the circuit during REM sleep. In other words, the brain favours the discrimination of safety versus danger in the dendrites, but block the over-reaction to emotion, in particular danger.

A survival advantage

According to the researchers, the coexistence of both mechanisms is beneficial to the stability and survival of the organisms: "This bi-directional mechanism is essential to optimize the discrimination between dangerous and safe signals," says Mattia Aime from the DBMR, first author of the study. If this discrimination is missing in humans and excessive fear reactions are generated, this can lead to anxiety disorders. The findings are particularly relevant to pathological conditions such as post-traumatic stress disorders, in which trauma is over-consolidated in the prefrontal cortex, day after day during sleep.

Breakthrough for sleep medicine

These findings pave the way to a better understanding of the processing of emotions during sleep in humans and open new perspectives for therapeutic targets to treat maladaptive processing of traumatic memories, such as Post Traumatic Stress Disorders (PTSD) and their early sleep-dependent consolidation. Additional acute or chronic mental health issues that may implicate this somatodendritic decoupling during sleep include acute and chronic stress, anxiety, depression, panic, or even anhedonia, the inability to feel pleasure. Sleep research and sleep medicine have long been a research focus of the University of Bern and the Inselspital, Bern University Hospital. "We hope that our findings will not only be of interest to the patients, but also to the broad public," says Adamantidis.

https://www.sciencedaily.com/releases/2022/05/220513113237.htm

Discovery reveals blocking inflammation may lead to chronic pain

Findings may lead to reconsideration of how we treat acute pain

May 12, 2022

Science Daily/McGill University

Using anti-inflammatory drugs and steroids to relieve pain could increase the chances of developing chronic pain, according to researchers from McGill University and colleagues in Italy. Their research puts into question conventional practices used to alleviate pain. Normal recovery from a painful injury involves inflammation and blocking that inflammation with drugs could lead to harder-to-treat pain.

"For many decades it's been standard medical practice to treat pain with anti-inflammatory drugs. But we found that this short-term fix could lead to longer-term problems," says Jeffrey Mogil, a Professor in the Department of Psychology at McGill University and E. P. Taylor Chair in Pain Studies.

The difference between people who get better and don't

In the study published in Science Translational Medicine, the researchers examined the mechanisms of pain in both humans and mice. They found that neutrophils -- a type of white blood cell that helps the body fight infection -- play a key role in resolving pain.

"In analyzing the genes of people suffering from lower back pain, we observed active changes in genes over time in people whose pain went away. Changes in the blood cells and their activity seemed to be the most important factor, especially in cells called neutrophils," says Luda Diatchenko a Professor in the Faculty of Medicine, Faculty of Dentistry, and Canada Excellence Research Chair in Human Pain Genetics.

Inflammation plays a key role in resolving pain

"Neutrophils dominate the early stages of inflammation and set the stage for repair of tissue damage. Inflammation occurs for a reason, and it looks like it's dangerous to interfere with it," says Professor Mogil, who is also a member of the Alan Edwards Centre for Research on Pain along with Professor Diatchenko.

Experimentally blocking neutrophils in mice prolonged the pain up to ten times the normal duration. Treating the pain with anti-inflammatory drugs and steroids like dexamethasone and diclofenac also produced the same result, although they were effective against pain early on.

Thesefindings are also supported by a separate analysis of 500,000 people in the United Kingdom that showed that those taking anti-inflammatory drugs to treat their pain were more likely to have pain two to ten years later, an effect not seen in people taking acetaminophen or anti-depressants.

Reconsidering standard medical treatment of acute pain

"Our findings suggest it may be time to reconsider the way we treat acute pain. Luckily pain can be killed in other ways that don't involve interfering with inflammation," says Massimo Allegri, a Physician at the Policlinico of Monza Hospital in Italy and Ensemble Hospitalier de la Cote in Switzerland.

"We discovered that pain resolution is actually an active biological process," says Professor Diatchenko. These findings should be followed up by clinical trials directly comparing anti-inflammatory drugs to other pain killers that relieve aches and pains but don't disrupt inflammation."

https://www.sciencedaily.com/releases/2022/05/220512092711.htm

Seeing more species at the coast improves wellbeing: Yet another benefit of biodiversity

May 11, 2022

Science Daily/Swansea University

Seeing a larger number of species on urban coastlines -- from marine animals to seaweed -- is likely to improve the wellbeing of local people and visitors, new research from a team at Swansea University has revealed. The findings provide further evidence that biodiversity brings wide-ranging benefits.

Studies of land-based environments such as meadows, woodlands, and city parks have shown that people often find places that contain lots of different types of plant and animal life to be more visually pleasing and interesting, as well as more likely to relieve stress.

However, we know much less about seashore species and whether they generate the same positive feelings that land-based wildlife does, despite almost half of the world's population living close to the coast.

Anecdotal evidence suggests that people may associate marine life such as seaweeds with unpleasant slimy textures and smells or perceive them to be messy additions to coastlines. As such, having a greater variety of coastal species may not lead to the same positive effects on wellbeing as are observed on land.

This is important because coastal structures like seawalls are becoming increasingly familiar sights and can be home to many different marine species. Many of them now incorporate measures to conserve or promote biodiversity, such as the Sea Hive project in Mumbles in Swansea, but how these might affect the perceptions and wellbeing of beach visitors isn't well understood.

To understand how biodiversity may shape peoples' views, scientists at Swansea University undertook a research study.

They recruited 937 participants from the UK and Ireland. They asked them how appealing, interesting, and calming they found images of seawalls with different numbers of seaweed and animal species on them.

The images included between zero and eight different marine species: comprising of different types of seaweeds, barnacles, limpets, mussels and anemones.

To see whether the type of seawall that seaweeds and animals were growing on changed peoples' views, images ranged across three different structure types: from regular-shaped concrete walls to more irregular boulder -- or "rip-rap" -- sea defences.

They also included two different viewing scales -- from the whole structure, to close-up viewing -- to see if how people view seawalls affects their perceptions.

The survey found: 

• Biologically diverse images on irregular structures were rated most favourably

• Respondents strongly and positively valued scenes that were seen as diverse, as they were seen as more interesting and calming

• The older sea wall and the rip rap were seen as more "natural" and therefore viewed more positively than the more "artificial" regular sea wall

• Diversity and naturalness were rated as the most important qualities in participants' comments

• This was especially true with close-up images, which is how people sometimes view coastal habitats, for example exploring or looking at rockpools

Dr Tom Fairchild of Swansea University, lead researcher, said:

"People found structures that had more species to be more appealing, interesting, and calming to look at. This suggests that high numbers of species provide a range of human benefits, despite occasional negative feelings towards species. This occurred because structures were perceived to be more "natural" and have greater "biodiversity" when they were home to a wide variety of sea life: strongly influencing how we see natural spaces.

As public awareness about human impacts on the natural world increases, projects to conserve or enhance biodiversity are becoming more common. Our study supports the idea that designing seawalls to support biodiversity not only brings benefits to wildlife but can also benefit the lives of people who live by or use our urban coastlines."

https://www.sciencedaily.com/releases/2022/05/220511102813.htm

Exposure to wildfires increases risk of cancer

Living near regions prone to wildfires may boost risk of developing lung cancer and brain tumors

May 9, 2022

Science Daily/McGill University

A new study from McGill University finds higher incidence of lung cancer and brain tumors in people exposed to wildfires. The study, which tracks over two million Canadians over a period of 20 years, is the first to examine how proximity to forest fires may influence cancer risk.

"Wildfires tend to happen in the same locations each year, but we know very little about the long-term health effects of these events. Our study shows that living in close proximity to wildfires may increase the risk of certain cancers," says Scott Weichenthal, an Associate Professor in the Department of Epidemiology, Biostatistics, and Occupational Health at McGill University.

Published in The Lancet Planetary Health, the study shows that people living within 50-kilometer of wildfires over the past 10 years had a 10 per cent higher incidence of brain tumors and 4.9 per cent higher incidence of lung cancer, compared to people living further away.

Impacts of climate change on human health

With the changing climate, wildfires are predicted to become more prevalent, severe, and longer in duration in the future -- and they are increasingly recognized as a global health problem. "Many of the pollutants emitted by wildfires are known human carcinogens, suggesting that exposure could increase cancer risk in humans," says Jill Korsiak, a PhD student in Professor Weichenthal's lab who led the analysis.

Wildfires typically occur in similar regions each year, and as a result, people living in nearby communities might be exposed to carcinogenic wildfire pollutants on a chronic basis, warn the researchers.

Lingering harmful pollutants

In addition to impacts on air quality, wildfires also pollute aquatic, soil, and indoor environments. While some pollutants return to normal concentrations shortly after the fire has stopped burning, other chemicals might persist in the environment for long periods of time, including heavy metals and hydrocarbons. "Exposure to harmful environmental pollutants might continue beyond the period of active burning through several routes of exposure," adds Professor Weichenthal.

Still, more research is necessary to understand the complex mixture of environmental pollutants released during wildfires, note the researchers. They also note that further work is needed to develop more long-term estimates of the chronic health effects of wildfires.

https://www.sciencedaily.com/releases/2022/05/220509191547.htm

A healthy lifestyle helps to prevent gestational diabetes in those at highest genetic risk

May 4, 2022

Science Daily/University of Helsinki

Researchers have developed a genetic-risk score for identifying individuals who would benefit the most from lifestyle counselling to prevent gestational and postpartum diabetes.

Gestational diabetes is the most common health-related challenge during pregnancy. Today, it is diagnosed in every fifth expectant mother in Finland. Gestational diabetes has a significant impact on the health of both the mother and the child, both during pregnancy and after delivery.

A study conducted at the University of Helsinki investigated the effects of lifestyle intervention on the prevention of gestational diabetes in women at high risk of developing gestational diabetes. In the Finnish Gestational Diabetes Prevention Study (RADIEL), the study subjects received intensified physical exercise and dietary counselling during pregnancy and for the first year following delivery.

In this study, a polygenic risk score (PRS) describing the genetic risk of diabetes was calculated using gene variants known to increase the risk of type 2 diabetes. The risk score for type 2 diabetes was associated with elevated glucose levels in mid- and late pregnancy as well as one year after delivery.

"Gestational diabetes as well as prediabetes and diabetes one year after delivery were also more common among those with higher scores," says Emilia Huvinen, specialist in obstetrics and gynaecology.

Targeted measures produce better results

The study discovered that genetic risk also affected the link between lifestyle counselling and gestational diabetes as well as diabetes.

"Based on our research, intensified lifestyle interventions benefitted only women at highest genetic risk of developing type 2 diabetes," Huvinen confirms.

According to her, the results are significant and even globally unique.

"Our study offers one possible explanation for the contradictory results of previous studies investigating the prevention of gestational diabetes till now ," Huvinen explains.

According to the researchers, genetic-risk scoring would make it possible to identify the expectant mothers most at risk as well as to direct resources and the most effective preventive measures specifically at them. This would be of great importance in terms of both limited societal resources and the health of these mothers and their children.

"At the same time, it's important to realise that, in the case of diabetes, our genetic background does not determine our future. With the help of a healthy lifestyle, you can reverse the effect of a high genetic diabetes risk," Huvinen says, offering encouragement.

https://www.sciencedaily.com/releases/2022/05/220504110443.htm

Loneliness leads to higher risk of future unemployment

Experiencing loneliness appears to lead to a higher risk of future unemployment

April 27, 2022

Science Daily/University of Exeter

A new study found that people who reported 'feeling lonely often' were significantly more likely to encounter unemployment later. The analysis also confirmed previous findings that the reverse is true -- people who were unemployed were more likely to experience loneliness later.

Previous research has established that being unemployed can cause loneliness, however the new study from the University of Exeter is the first to directly explore whether the opposite also applies across the working age population. Published in BMC Public Health, the study found that people who reported "feeling lonely often" were significantly more likely to encounter unemployment later. Their analysis also confirmed previous findings that the reverse is true -- people who were unemployed were more likely to experience loneliness later.

Lead author Nia Morrish, of the University of Exeter, said: "Given the persisting and potentially scarring effects of both loneliness and unemployment on health and the economy, prevention of both experiences is key. Decreased loneliness could mitigate unemployment, and employment abate loneliness, which may in turn relate positively to other factors including health and quality of life. Thus, particular attention should be paid to loneliness with additional support from employers and government to improve health and wellbeing. Our research was largely conducted pre-pandemic, however we suspect this issue may be even more pressing, with more people working from home and potentially experiencing isolation because of anxieties around covid."

The research analysed largely pre-pandemic data from more than 15,000 people in the Understanding Society Household Longitudinal Study. The team analysed responses from the participants during 2017-2019, then from 2018-2020, controlling for factors including age, gender, ethnicity, education, marital status, household composition, number of own children in household and region.

Senior author Professor Antonieta Medina-Lara said: "Loneliness is an incredibly important societal problem, which is often thought about in terms of the impact on mental health and wellbeing only. Our findings indicate that there may also be wider implications, which could have negative impacts for individuals and the economy. We need to explore this further, and it could lay the foundations for employers or policy makers to tackle loneliness with a view to keeping more people in work."

Paper co-author Dr Ruben Mujica-Mota, Associate Professor of Health Economics in the University of Leeds' School of Medicine, said: "While previous research has shown that unemployment can cause loneliness, ours is the first study to identify that lonely people of any working age are at greater risk of becoming unemployed. Our findings show that these two issues can interact and create a self-fulfilling, negative cycle. There is a need for greater recognition of the wider societal impacts of loneliness in the working age population."

https://www.sciencedaily.com/releases/2022/04/220427211258.htm

Living in areas with more greenery may boost cognitive function

April 28, 2022

Science Daily/Boston University School of Public Health

Cognitive function at middle age is a strong predictor of whether a person may develop dementia later in life. Now, a new study led by a Boston University School of Public Health (BUSPH) researcher has found that increasing greenspace in residential areas could help improve cognition function in middle-aged women and that this association might be explained by a reduction in depression, which is also a risk factor for dementia.

Published in the journal JAMA Network Open, the study found that exposure to greenspace around one's home and surrounding neighborhood could improve processing speed and attention, as well as boost overall cognitive function. The results also showed that lowered depression may help explain the association between greenspace and cognition, bolstering previous research that has linked exposure to parks, community gardens, and other greenery with improved mental health.

"Some of the primary ways that nature may improve health is by helping people recover from psychological stress and by encouraging people to be outside socializing with friends, both of which boost mental health," says Dr. Marcia Pescador Jimenez, study lead and corresponding author, and assistant professor of epidemiology at BUSPH. "This study is among the few to provide evidence that greenspace may benefit cognitive function in older ages. Our findings suggest that greenspace should be investigated as a potential population-level approach to improve cognitive function."

For the study, Pescador Jimenez and colleagues from BUSPH, Harvard T.H. Chan School of Public Health, Brigham and Women Hospital, Harvard Medical School, and Rush Medical College estimated residential greenspace with a satellite image-based metric called the Normalized Difference Vegetation Index (NDVI). They measured psychomotor speed, attention, learning, and working memory among 13,594 women aged 61 on average and primarily White, from 2014 to 2016. The women were participants in the Nurses' Health Study II, the second of three studies that are among the largest investigations into the risk factors for chronic diseases among US women.

Adjusting for age, race, and individual and neighborhood socioeconomic status, the researchers found that greenspace exposure was associated with psychomotor speed and attention, but not learning or working memory.

In addition to depression, the researchers also examined the potential roles of air pollution and physical activity in explaining the association between greenspace and cognitive function, and they were surprised to only find evidence of depression as a mediating factor.

"We theorize that depression might be an important mechanism through which green space may slow down cognitive decline, particularly among women, but our research is ongoing to better understand these mechanisms," Pescador Jimenez says. "Based on these results, clinicians and public health authorities should consider green space exposure as a potential factor to reduce depression, and thus, boost cognition. Policymakers and urban planners should focus on adding more green space in everyday life to improve cognitive function."

While the study shows evidence of this association, the greenspace metric that the researchers used to measure greenspace exposure does not differentiate between specific types of vegetation. In a new project, Pescador Jimenez will apply deep learning algorithms to Google Street View images to better understand which specific elements of greenery, such as trees or grass, could be the driving factors for health.

The researchers also hope that their study is replicated among other racial/ethnic populations and assesses associations with cognitive decline over longer periods of time.

"The distribution of green spaces in cities is not uniform," says Pescador Jimenez. "Increasing everyday access to vegetation across vulnerable groups in urban cities is a crucial next step to achieve health equity."

https://www.sciencedaily.com/releases/2022/04/220427115708.htm

When it comes to preventing Alzheimer's, women respond better than men

April 26, 2022

Science Daily/Florida Atlantic University

A study is the first to examine if sex significantly affects cognitive outcomes in people who follow individually-tailored, multi-domain clinical interventions. The study also determined whether change in risk of developing cardiovascular disease (CVD) and Alzheimer's disease (AD), along with blood markers of AD risk, also were affected by sex. Results showed that while care in an Alzheimer's Prevention Clinic setting is equally effective at improving cognitive function in both women and men, the personally-tailored interventions used by the researchers led to greater improvements in women compared to men across AD and CVD disease risk scales, as well blood biomarkers of risk such as blood sugar, LDL cholesterol, and the diabetes test HbA1C. Findings are important because women are disproportionately affected by AD and population-attributable risk models suggest that managing risk factors can prevent up to one-third of dementia cases.

After increasing age, the most significant risk factor for Alzheimer's disease (AD) is sex -- two-thirds of patients with AD are females. In fact, even when accounting for gender-dependent mortality rates, age at death, and differences in lifespan, women still have twice the risk of incidence.

A study headed by Florida Atlantic University's Richard S. Isaacson, M.D., a leading neurologist and researcher, and collaborators from NewYork-Presbyterian/Weill Cornell Medicine, is the first to examine if sex significantly affects cognitive outcomes in people who follow individually-tailored, multi-domain clinical interventions. The study also determined whether change in risk of developing cardiovascular disease and AD, along with blood markers of AD risk, also were affected by sex. Other studies have focused on the role of hormones and sex-specific risk factors when examining differences in AD risk, but none have explored if these interventions result in differences in real-world clinical practice.

The study is an analysis of the Comparative Effectiveness Dementia & Alzheimer's Registry (CEDAR) trial launched at Weill Medicine in 2015 and spearheaded by Isaacson, which has already demonstrated that individualized, multi-domain interventions improved cognition and reduced the risk of AD in both women and men.

In the sub-group analysis, researchers evaluated the differential effectiveness of the clinical approach itself when considering sex in higher-compliance participants (n=80) from the original study cohort (n=154). Within this cohort, similar to the original study, participants were categorized by baseline diagnoses: normal cognition, subjective cognitive decline, and preclinical AD participants were classified as "Prevention." Mild cognitive impairment due to AD and mild AD were classified as "Early Treatment."

Results of the study, published in the Journal of Prevention of Alzheimer's Disease, showed that risk reduction care in an Alzheimer's Prevention Clinic setting led to improvements in cognition in both women and men without sex-differences. However, in the Prevention group, women demonstrated greater improvements in the Multi-Ethnic Study of Atherosclerosis risk score (MESA) than men. Women in the Early Treatment group also demonstrated greater improvements in CV Risk Factors, Aging and Incidence of Dementia (CAIDE) risk score and the MESA-RS. The CAIDE is a validated risk index that calculates late-life dementia risk based on midlife vascular risk factors such as body mass index, blood pressure, cholesterol and smoking status, while the MESA estimates one's risk of cardiovascular disease incidence over the next ten years using traditional risk factors.

"While care in an Alzheimer's Prevention Clinic setting is equally effective at improving cognitive function in both women and men, our personally-tailored interventions led to greater improvements in women compared to men across Alzheimer's and cardiovascular disease risk scales, as well blood biomarkers of risk such as blood sugar, LDL cholesterol, and the diabetes test HbA1C," said Isaacson, lead author and director of the newly launched FAU Center for Brain Health and the Alzheimer's Prevention Clinic within the Schmidt College of Medicine, who conducted the study while at Weill Cornell Medicine and NewYork-Presbyterian. "Our findings are important because women are disproportionately affected by Alzheimer's disease and population-attributable risk models suggest that managing risk factors can prevent up to one-third of dementia cases, highlighting the immense potential that lies in addressing modifiable risk factors."

After undergoing baseline clinical assessments, which included a detailed clinical history, physical examination, anthropometrics, blood biomarkers, apolipoprotein-?4 (APOE-e4) genotyping, and cognitive assessment, patients in the CEDAR study were given individually-tailored, multi-domain intervention recommendations informed by these clinical and biomarker data. Recommendation categories included patient education/genetic counseling, individualized pharmacological approaches (medications/vitamins/supplements), non-pharmacological approaches (exercise counseling, dietary counseling, vascular risk reduction, sleep hygiene, cognitive engagement, stress reduction, and general medical care) and other evidence-based interventions.

"Our latest results suggest that the individualized management approach used by the CEDAR study in a real-world clinic may offer equal cognitive benefits to both women and men, as well as better mitigation of calculated Alzheimer's disease and cardiovascular disease risk in women compared to men," said Isaacson. "Our work also highlights the need for larger studies focusing on sex differences in AD-related cognitive trajectories, as the existing body of knowledge lacks conclusive evidence on this issue."

Isaacson and collaborators are planning on larger cohorts to further define sex differences in AD risk reduction in clinical practice and hope to launch a multi-site international study soon to draw more definitive conclusions.

https://www.sciencedaily.com/releases/2022/04/220426101641.htm

An ocean in your brain: Interacting brain waves key to how we process information

Scientists show how the brain responds differently to seeing the same thing under different conditions

April 22, 2022

Science Daily/Salk Institute

For years, the brain has been thought of as a biological computer that processes information through traditional circuits, whereby data zips straight from one cell to another. While that model is still accurate, a new study led by Salk Professor Thomas Albright and Staff Scientist Sergei Gepshtein shows that there's also a second, very different way that the brain parses information: through the interactions of waves of neural activity. The findings, published in Science Advances on April 22, 2022, help researchers better understand how the brain processes information.

"We now have a new understanding of how the computational machinery of the brain is working," says Albright, the Conrad T. Prebys Chair in Vision Research and director of Salk's Vision Center Laboratory. "The model helps explain how the brain's underlying state can change, affecting people's attention, focus, or ability to process information."

Researchers have long known that waves of electrical activity exist in the brain, both during sleep and wakefulness. But the underlying theories as to how the brain processes information -- particularly sensory information, like the sight of a light or the sound of a bell -- have revolved around information being detected by specialized brain cells and then shuttled from one neuron to the next like a relay.

This traditional model of the brain, however, couldn't explain how a single sensory cell can react so differently to the same thing under different conditions. A cell, for instance, might become activated in response to a quick flash of light when an animal is particularly alert, but will remain inactive in response to the same light if the animal's attention is focused on something else.

Gepshtein likens the new understanding to wave-particle duality in physics and chemistry -- the idea that light and matter have properties of both particles and waves. In some situations, light behaves as if it is a particle (also known as a photon). In other situations, it behaves as if it is a wave. Particles are confined to a specific location, and waves are distributed across many locations. Both views of light are needed to explain its complex behavior.

"The traditional view of brain function describes brain activity as an interaction of neurons. Since every neuron is confined to a specific location, this view is akin to the description of light as a particle," says Gepshtein, director of Salk's Collaboratory for Adaptive Sensory Technologies. "We've found that in some situations, brain activity is better described as interaction of waves, which is similar to the description of light as a wave. Both views are needed for understanding the brain."

Some sensory cell properties observed in the past were not easy to explain given the "particle" approach to the brain. In the new study, the team observed the activity of 139 neurons in an animal model to better understand how the cells coordinated their response to visual information. In collaboration with physicist Sergey Savel'ev of Loughborough University, they created a mathematical framework to interpret the activity of neurons and to predict new phenomena.

The best way to explain how the neurons were behaving, they discovered, was through interaction of microscopic waves of activity rather than interaction of individual neurons. Rather than a flash of light activating specialized sensory cells, the researchers showed how it creates distributed patterns: waves of activity across many neighboring cells, with alternating peaks and troughs of activation -- like ocean waves.

When these waves are being simultaneously generated in different places in the brain, they inevitably crash into one another. If two peaks of activity meet, they generate an even higher activity, while if a trough of low activity meets a peak, it might cancel it out. This process is called wave interference.

"When you're out in the world, there are many, many inputs and so all these different waves are generated," says Albright. "The net response of the brain to the world around you has to do with how all these waves interact."

To test their mathematical model of how neural waves occur in the brain, the team designed an accompanying visual experiment. Two people were asked to detect a thin faint line ("probe") located on a screen and flanked by other light patterns. How well the people performed this task, the researchers found, depended on where the probe was. The ability to detect the probe was elevated at some locations and depressed at other locations, forming a spatial wave predicted by the model.

"Your ability to see this probe at every location will depend on how neural waves superimpose at that location," says Gepshtein, who is also a member of Salk's Center for the Neurobiology of Vision. "And we've now proposed how the brain mediates that."

The discovery of how neural waves interact is much more far-reaching than explaining this optical illusion. The researchers hypothesize that the same kinds of waves are being generated -- and interacting with each other -- in every part of the brain's cortex, not just the part responsible for the analysis of visual information. That means waves generated by the brain itself, by subtle cues in the environment or internal moods, can change the waves generated by sensory inputs.

This may explain how the brain's response to something can shift from day to day, the researchers say.

https://www.sciencedaily.com/releases/2022/04/220422161527.htm

Stress, anxiety and depression during pregnancy may hinder toddler's cognitive development

April 29, 2022

Science Daily/Children's National Hospital

Women's elevated anxiety, depression and stress during pregnancy altered key features of the fetal brain, which subsequently decreased their offspring's cognitive development at 18 months. These changes also increased internalizing and dysregulation behaviors, according to a new study by Children's National Hospital published in JAMA Network Open. Researchers followed a cohort of 97 pregnant women and their babies. The findings further suggest that persistent psychological distress after the baby is born may influence the parent-child interaction and infant self-regulation.

This is the first study to shed light on an important link between altered in-utero fetal brain development and the long-term cognitive development consequences for fetuses exposed to high levels of toxic stress during pregnancy. While in the womb, the researchers observed changes in the sulcal depth and left hippocampal volume, which could explain the neurodevelopment issues seen after birth. Once they grow into toddlers, these children may experience persistent social-emotional problems and have difficulty establishing positive relationships with others, including their mothers. To further confirm this, future studies with a larger sample size that reflect more regions and populations are needed.

"By identifying the pregnant women with elevated levels of psychological distress, clinicians could recognize those babies who are at risk for later neurodevelopmental impairment and might benefit from early, targeted interventions," said Catherine Limperopoulos, Ph.D., chief and director of the Developing Brain Institute at Children's National and senior author of the study.

Regardless of their socioeconomic status, about one of every four pregnant women suffers from stress-related symptoms, the most common pregnancy complication. The relationship between altered fetal brain development, prenatal maternal psychological distress and long-term neurodevelopmental outcomes remain unknown. Studying in utero fetal brain development poses challenges due to fetal and maternal movements, imaging technology, signal-to-noise ratio issues and changes in brain growth.

All pregnant participants were healthy, most had some level of education and were employed. To quantify prenatal maternal stress, anxiety and depression, the researchers used validated self-reported questionnaires. Fetal brain volumes and cortical folding were measured from three-dimensional reconstructed images derived from MRI scans. Fetal brain creatine and choline were quantified using proton magnetic resonance spectroscopy. The 18-month child neurodevelopment was measured using validated scales and assessments.

This study builds upon previous work from the Developing Brain Institute led by Limperopoulos, which discovered that anxiety in pregnant women appears to affect the brain development of their babies. Her team also found that maternal mental health, even for women with high socioeconomic status, alters the structure and biochemistry of the developing fetal brain. The growing evidence underscores the importance of mental health support for pregnant women.

"We're looking at shifting the health care paradigm and adopting these changes more broadly to better support moms," said Limperopoulos. "What's clear is early interventions could help moms reduce their stress, which can positively impact their symptoms and thereby their baby long after birth."

https://www.sciencedaily.com/releases/2022/04/220429144916.htm

Acute sleep loss may alter the way we see others

May 3, 2022

Science Daily/Uppsala University

A new study from Uppsala University shows that young adults when sleep-deprived evaluate angry faces as less trustworthy and healthy-looking. Furthermore, neutral and fearful faces appear less attractive following sleep loss. The findings are published in the scientific journal Nature and Science of Sleep.

Using eye-tracking, a sensor technology that can detect what a person is looking at in real time, researchers from Uppsala University in Sweden performed an experiment on 45 young men and women to examine how acute sleep loss affects the way humans explore and evaluate happy, fearful, angry and neutral faces. The participants spent one night with no sleep at all and one night with an eight-hour sleep opportunity. Their eye movements were measured in the mornings following both nights.

"When sleep-deprived, our research subjects spent less time fixating on faces. Since facial expressions are crucial to understanding the emotional state of others, spending less time fixating on faces after acute sleep loss may increase the risk that you interpret the emotional state of others inaccurately or too late," says Lieve van Egmond, first author and PhD student in the Department of Surgical Sciences at Uppsala University.

"The finding that sleep-deprived subjects in our experiment rated angry faces as less trustworthy and healthy-looking and neutral and fearful faces as less attractive indicates that sleep loss is associated with more negative social impressions of others. This could result in less motivation to interact socially," says senior author Christian Benedict, Associate Professor of Neuroscience.

"Our participants were young adults. Thus, we do not know whether our results are generalisable to other age groups. Moreover, we do not know if similar results would be seen among those suffering from chronic sleep loss," says Lieve van Egmond.

https://www.sciencedaily.com/releases/2022/05/220503102900.htm

Study finds children with vegetarian diet have similar growth and nutrition compared to children who eat meat

Children with a vegetarian diet also had higher odds of underweight weight status

May 2, 2022

Science Daily/St. Michael's Hospital

A study of nearly 9,000 children found those who eat a vegetarian diet had similar measures of growth and nutrition compared to children who eat meat. The study, published in Pediatrics and led by researchers at St. Michael’s Hospital of Unity Health Toronto, also found that children with a vegetarian diet had higher odds of underweight weight status, emphasizing the need for special care when planning the diets of vegetarian kids.

The findings come as a shift to consuming a plant-based diet grows in Canada. In 2019, updates to Canada’s Food Guide urged Canadians to embrace plant-based proteins, such as beans and tofu, instead of meat.

“Over the last 20 years we have seen growing popularity of plant-based diets and a changing food environment with more access to plant-based alternatives, however we have not seen research into the nutritional outcomes of children following vegetarian diets in Canada,” said Dr. Jonathon Maguire, lead author of the study and a pediatrician at St. Michael’s Hospital of Unity Health Toronto.

“This study demonstrates that Canadian children following vegetarian diets had similar growth and biochemical measures of nutrition compared to children consuming non-vegetarian diets. Vegetarian diet was associated with higher odds of underweight weight status, underscoring the need for careful dietary planning for children with underweight when considering vegetarian diets.”

Researchers evaluated 8,907 children age six months to eight years. The children were all participants of the TARGet Kids! cohort study and data was collected between 2008 and 2019. Participants were categorized by vegetarian status – defined as a dietary pattern that excludes meat – or non-vegetarian status.

Researchers found children who had a vegetarian diet had similar mean body mass index (BMI), height, iron, vitamin D, and cholesterol levels compared to those who consumed meat. The findings showed evidence that children with a vegetarian diet had almost two-fold higher odds of having underweight, which is defined as below the third percentile for BMI. There was no evidence of an association with overweight or obesity.

Underweight is an indicator of undernutrition, and may be a sign that the quality of the child’s diet is not meeting the child’s nutritional needs to support normal growth. For children who eat a vegetarian diet, the researchers emphasized access to healthcare providers who can provide growth monitoring, education and guidance to support their growth and nutrition.

International guidelines about vegetarian diet in infancy and childhood have differing recommendations, and past studies that have evaluated the relationship between vegetarian diet and childhood growth and nutritional status have had conflicting findings.

“Plant-based dietary patterns are recognized as a healthy eating pattern due to increased intake of fruits, vegetables, fiber, whole grains, and reduced saturated fat; however, few studies have evaluated the impact of vegetarian diets on childhood growth and nutritional status. Vegetarian diets appear to be appropriate for most children,” said Dr. Maguire, who is also a scientist at MAP Centre for Urban Health Solutions at St. Michael’s Hospital.

A limitation of the study is that researchers did not assess the quality of the vegetarian diets. The researchers note that vegetarian diets come in many forms and the quality of the individual diet may be quite important to growth and nutritional outcomes. The authors say further research is needed to examine the quality of vegetarian diets in childhood, as well as growth and nutrition outcomes among children following a vegan diet, which excludes meat and animal derived products such as dairy, egg, and honey.

https://www.sciencedaily.com/releases/2022/05/220502094813.htm