Anxious people use less suitable section of brain to control emotions

August 17, 2023

Science Daily/Radboud University Nijmegen

When choosing their behaviour in socially difficult situations, anxious people use a less suitable section of the forebrain than people who are not anxious. This can be seen in brain scans, as shown by the research of Bob Bramson and Sjoerd Meijer at the Donders Institute of Radboud University.

For example, an anxious and a non-anxious person both run into someone whom they've been in love with for quite some time. Both of them find this tense and both would like to ask the person out on a date. But do you walk up to that person? Or do you pretend not to see them to avoid embarrassment? Whereas the non-anxious person can put aside this emotion and choose behaviour that allows them to approach the potential lover, this is much more difficult for an anxious person. Bramson: "Anxious people use a less suitable section of the forebrain for this control. It's more difficult for them to choose alternative behaviour, so they avoid social situations more often."

Decisions like this demand a balancing act between a possible threat and a reward, a decision that non-anxious people make in the prefrontal cortex. Researchers at Radboud University have now shown that socially anxious people use a different section in the forebrain for decisions like this.

Brain scans

Bramson and Meijer studied brain scans to see what happens in anxious and non-anxious people in a simulated social situation. "Our trial subjects were shown happy and angry faces and had to first move a joystick towards the happy face and away from the angry face. At a certain point they had to do the reverse: move towards an angry face and away from a happy face. This demands control over our automatic tendency to avoid negative situations."

Anxious people proved to perform just as well as non-anxious people in this simple task, but the scans showed that a completely different section of the brain was active. "In non-anxious people we often see that, during emotional control, a signal is sent from the foremost section of the prefrontal cortex to the motor cortex, the section of the brain that directs your body to act. In anxious people a less efficient section of that foremost section is used." Other scans showed that the reason for this is probably because the 'correct' section becomes overstimulated in anxious people. "This could explain why anxious people find it difficult to choose alternative behaviour and thus avoid social situations. The disadvantage of this is that they never learn that social situations aren't as negative as they think."

Treating anxiety

For the first time, brain scans have now shown that the forebrain of anxious people works differently from that of non-anxious people with regard to control of emotional behaviour. The researchers think that the results could be used to develop new treatments for people with anxiety.

https://www.sciencedaily.com/releases/2023/08/230817163956.htm

Heredity and environment account for people's love of nature

August 17, 2023

Science Daily/University of Gothenburg

Humans have a positive view of nature. But is this due to an approach we have learned while growing up, or is it something we are born with? The answer is 'Both', according to researchers at the University of Gothenburg and the Swedish University of Agricultural Sciences. Our love of nature is highly individual and should influence how we plan our cities, say the researchers.

It is well known that nature has a positive effect on people. In cities in particular, studies have shown that trees and other greenery contribute to people's wellbeing. However, experts do not agree on the reasons behind this phenomenon, known as biophilia.

Some believe that it is natural for humans to feel an automatic positive attachment because human development has occurred in nature. Others argue that there is no evidence for this, and that influences during our childhood determine how we view nature.

A wide range of factors involved

Researchers from the University of Gothenburg and the Swedish University of Agricultural Sciences (SLU) have reviewed several studies within this field that examine both innate factors and what individuals experience during their lives, primarily as children. In a new scientific article, the researchers conclude that both heredity and environment influence an individual's attitude to nature, but that a wide range of factors also influence how love of nature is expressed.

"We have been able to establish that many people have an unconscious positive experience of nature," says Bengt Gunnarsson, Professor Emeritus of Environmental Science at the University of Gothenburg. "But the biophilia hypothesis should be modified to link the variation in individuals' relationships with nature to an interaction between heredity and environmental influence."

Nature mean different things

This is because people react differently to nature. In a Japanese study, subjects were asked to walk in a forest and in a city while their heartbeat was measured. This showed that positive emotions while walking in a forest increased in 65% of people. Thus, far from everyone had a positive perception of nature. Another environmental psychology study found that research subjects are unconsciously drawn to nature instead of cities, and that this attraction was reinforced in those whose childhood was rich in nature.

"An additional study on identical and non-identical twins showed that a genetic component influences an individual's positive or negative relationship with nature," continues Bengt. "But the study also highlighted the importance of environment in terms of attitudes towards nature."

Moreover, nature can mean completely different things to different people. Some enjoy parks with lawns and planted trees, while others prefer being in the wilderness. The researchers believe that this variation is also determined by both heredity and environment.

"So it's important that we don't standardise nature when planning greenery in our towns and cities," adds Marcus Hedblom, a researcher at SLU and co-author of the article. "We shouldn't replace wild greenery with a park and assume that it will be good for everyone."

Urban nature brings many benefits

In today's urban planning, densification has been a common way to achieve a more sustainable city. This can sometimes come into conflict with efforts to offer nature in cities. A large number of studies suggest that urban parks and green spaces contribute to increased physical activity and recovery from stress. The greenery in our cities is also important in other respects. Trees can clean the air and provide shade to create a tolerable urban climate on hot days.

"There are probably quite a large number of people who do not have such positive feelings towards nature, partly due to hereditary factors," concludes Bengt. "Future studies that dig deeper into the interactions between hereditary and environmental factors are essential if we are to understand what shapes individuals' relationships with nature. But we have to remember that we are all different, and take that into account when planning for different natural areas in towns and cities. Let people find their own favourite green spaces!"

https://www.sciencedaily.com/releases/2023/08/230817163607.htm

Several vaccines associated with reduced risk of Alzheimer's disease in adults 65 and older

August 16, 2023

Science Daily/University of Texas Health Science Center at Houston

Prior vaccination against tetanus and diphtheria, with or without pertussis (Tdap/Td); herpes zoster (HZ), better known as shingles; and pneumococcus are all associated with a reduced risk for developing Alzheimer's disease, according to new research from UTHealth Houston.

A pre-press version of a study was published online recently in the Journal of Alzheimer's Disease. It was led by co-first authors Kristofer Harris, program manager in the Department of Neurology with McGovern Medical School at UTHealth Houston; Yaobin Ling, graduate research assistant with McWilliams School of Biomedical Informatics at UTHealth Houston; and Avram Bukhbinder, MD, an alumnus of the medical school. Paul E. Schulz, MD, the Rick McCord Professor in Neurology with McGovern Medical School, was senior author of the paper, which will appear in print in the Sept. 12 issue of the journal, Volume (95) Issue (2).

Alzheimer's disease affects more than 6 million people living in the U.S., with the number of affected individuals growing due to the nation's aging population.

The new findings come just over a year after Schulz's team published another study in the journal, which found that people who received at least one influenza vaccine were 40% less likely than their unvaccinated peers to develop Alzheimer's disease.

"We were wondering whether the influenza finding was specific to the flu vaccine. This data revealed that several additional adult vaccines were also associated with a reduction in the risk of Alzheimer's," said Schulz, who is the Umphrey Family Professor in Neurodegenerative Diseases and director of the Neurocognitive Disorders Center at McGovern Medical School. "We and others hypothesize that the immune system is responsible for causing brain cell dysfunction in Alzheimer's. The findings suggest to us that vaccination is having a more general effect on the immune system that is reducing the risk for developing Alzheimer's."

Researchers performed a retrospective cohort study that included patients who were free of dementia during a two-year lookback period and were at least 65 years old by the start of the eight-year follow-up period. They compared two similar groups of patients using propensity score matching, one vaccinated and another unvaccinated, with Tdap/Td, HZ, or pneumococcal vaccine. Ultimately, they calculated the relative risk and absolute risk reduction for developing Alzheimer's disease.

"This study underscores the pivotal role that large-scale, observational datasets play in biomedical research," Ling said. "It's particularly encouraging to observe consistent results across numerous large-scale health care databases."

"By leveraging modern data analysis models and the very large claims database subscribed by McWilliams School of Biomedical Informatics, we gained valuable insights into which vaccines may protect against Alzheimer's and potentially develop more effective prevention strategies," said Xiaoqian Jiang, PhD, a co-author on the study who holds the Christopher Sarofim Family Professorship in Biomedical Informatics and Bioengineering with McWilliams School of Biomedical Informatics.

https://www.sciencedaily.com/releases/2023/08/230816170628.htm

Adherence to a Mediterranean lifestyle associated with lower risk of all-cause and cancer mortality

August 16, 2023

Science Daily/Harvard T.H. Chan School of Public Health

People who adhere to a Mediterranean lifestyle -- which includes a diet rich in fruits, vegetables, and whole grains; healthy eating habits like limiting added salts and sugars; and habits promoting adequate rest, physical activity, and socialization -- have a lower risk of all-cause and cancer mortality, according to a new study led by La Universidad Autónoma de Madrid and Harvard T.H. Chan School of Public Health. People who adhered to the lifestyle's emphasis on rest, exercise, and socializing with friends had a lower risk of cardiovascular disease mortality.

The study will be published on Wednesday, August 16, in Mayo Clinic Proceedings.

While many studies have established the health benefits of a Mediterranean diet and lifestyle, little research has been conducted on the diet outside of its region of origin. "This study suggests that it's possible for non-Mediterranean populations to adopt the Mediterranean diet using locally available products and to adopt the overall Mediterranean lifestyle within their own cultural contexts," said lead author Mercedes Sotos Prieto, Ramon y Cajal research fellow at La Universidad Autónoma de Madrid and adjunct assistant professor of environmental health at Harvard Chan School. "We're seeing the transferability of the lifestyle and its positive effects on health."

The researchers analyzed the habits of 110,799 members of the UK Biobank cohort, a population-based study across England, Wales, and Scotland using the Mediterranean Lifestyle (MEDLIFE) index, which is derived from a lifestyle questionnaire and diet assessments. Participants, who were between the ages of 40 and 75, provided information about their lifestyle according to the three categories the index measures: "Mediterranean food consumption" (intake of foods part of the Mediterranean diet such as fruits and whole grains); "Mediterranean dietary habits" (adherence to habits and practices around meals, including limiting salt and drinking healthy beverages); and "physical activity, rest, and social habits and conviviality" (adherence to lifestyle habits including taking regular naps, exercising, and spending time with friends). Each item within the three categories was then scored, with higher total scores indicating higher adherence to the Mediterranean lifestyle.

The researchers followed up nine years later to examine participants' health outcomes. Among the study population, 4,247 died from all causes; 2,401 from cancer; and 731 from cardiovascular disease. Analyzing these results alongside MEDLIFE scores, the researchers observed an inverse association between adherence to the Mediterranean lifestyle and risk of mortality. Participants with higher MEDLIFE scores were found to have a 29% lower risk of all-cause mortality and a 28% lower risk of cancer mortality compared to those with lower MEDLIFE scores. Adherence to each MEDLIFE category independently was associated with lower all-cause and cancer mortality risk. The "physical activity, rest, and social habits and conviviality" category was most strongly associated with these lowered risks, and additionally was associated with a lower risk of cardiovascular disease mortality.

https://www.sciencedaily.com/releases/2023/08/230816170623.htm

How cold temperatures trigger the brain to boost appetite

August 16, 2023

Science Daily/Scripps Research Institute

Neuroscientists at Scripps Research have identified brain circuits that make mammals want to eat more when they are exposed to cold temperatures.

Mammals automatically burn more energy to maintain normal body temperature when exposed to cold. This cold-activated increase in energy expenditure triggers an increase in appetite and feeding, although the specific mechanism controlling this had been unknown. In the new study, reported on August 16, 2023, in Nature, the researchers identified a cluster of neurons that work as a "switch" for this cold-related, food-seeking behavior in mice. The discovery could lead to potential therapeutics for metabolic health and weight loss.

"This is a fundamental adaptive mechanism in mammals and targeting it with future treatments might allow the enhancement of the metabolic benefits of cold or other forms of fat burning," says study senior author Li Ye, PhD, associate professor and the Abide-Vividion Chair in Chemistry and Chemical Biology at Scripps Research.

The study's first author was Ye Lab postdoctoral research associate Neeraj Lal, PhD.

Because exposure to cold leads to enhanced energy burning to stay warm, cold water immersion and other forms of "cold therapy" have been explored as methods for losing weight and improving metabolic health. One drawback of cold therapies is that humans' evolved responses to cold are not designed to cause weight loss (an effect that could have been fatal during the frequent periods of food scarcity in pre-modern times). Cold, like dieting and exercise, increases appetite to counteract any weight-loss effect. In the study, Ye and his team set out to identify the brain circuitry that mediates this cold-induced appetite increase.

One of their first observations was that, with the onset of cold temperatures (from 73F to 39F), mice increase their food seeking only after a delay of about six hours, suggesting this behavioral change is not simply a direct result of cold sensing.

Using techniques called whole-brain clearing and light sheet microscopy, the researchers compared the activity of neurons across the brain during cold versus warm conditions. Soon they made a key observation: While most of the neuronal activity across the brain was much lower in the cold condition, portions of a region called the thalamus showed higher activation.

Eventually, the team zeroed in on a specific cluster of neurons called the xiphoid nucleus of the midline thalamus, showing that activity in these neurons spiked under cold conditions just before the mice stirred from their cold-induced torpor to look for food. When less food was available at the onset of the cold condition, the activity increase in the xiphoid nucleus was even greater -- suggesting that these neurons respond to a cold-induced energy deficit rather than cold itself.

When the researchers artificially activated these neurons, the mice increased their food-seeking, but not other activities. Similarly, when the team inhibited the activity of these neurons, the mice decreased their food-seeking. These effects appeared only under the cold condition, implying that cold temperatures provide a separate signal that must also be present for appetite changes to occur.

In a last set of experiments, the team showed that these xiphoid nucleus neurons project to a brain region called the nucleus accumbens -- an area long known for its role in integrating reward and aversion signals to guide behavior, including feeding behavior.

Ultimately, these results may have clinical relevance, Ye says, for they suggest the possibility of blocking the usual cold-induced appetite increase, allowing relatively simple cold exposure regimens to drive weight loss much more efficiently.

"One of our key goals now is to figure out how to decouple the appetite increase from the energy-expenditure increase," he says. "We also want to find out if this cold-induced appetite-increase mechanism is part of a broader mechanism the body uses to compensate for extra energy expenditure, for example after exercise."

https://www.sciencedaily.com/releases/2023/08/230816114222.htm

Certain sugars affect brain 'plasticity,' helping with learning, memory, recovery

August 16, 2023

Science Daily/American Chemical Society

Can you recognize someone you haven't seen in years, but forget what you had for breakfast yesterday? Our brains constantly rearrange their circuitry to remember familiar faces or learn new skills, but the molecular basis of this process isn't well understood. Today, scientists report that sulfate groups on complex sugar molecules called glycosaminoglycans (GAGs) affect "plasticity" in the brains of mice. Determining how GAGs function could help us understand how memory and learning work in humans, and provide ways to repair neural connectivity after injuries.

The researchers will present their results today at the fall meeting of the American Chemical Society (ACS).

The sugars that sweeten fruits, candies or cakes are actually just a few simple varieties of the many types of sugars that exist. When strung together, they can make a wide array of complex sugars. GAGs are formed by then attaching other chemical structures, including sulfate groups.

"If we study the chemistry of GAGs in the brain, we can learn about brain plasticity and hopefully, in the future, use this information to restore or enhance neural connections involved in memory," says Linda Hsieh-Wilson, Ph.D., the project's principal investigator presenting the research at the meeting.

"These sugars regulate numerous proteins, and their structures change during development and with disease," she explains. Hsieh-Wilson is at the California Institute of Technology.

In the brain, the most common GAG form is chondroitin sulfate, which is found throughout the extracellular matrix surrounding the brain's many cells. Chondroitin sulfate can also form structures known as "perineuronal nets," which wrap around individual neurons and stabilize the synaptic connections between them.

One way a GAG's function can be changed is through sulfation motifs, or patterns of sulfate groups tacked onto the sugar chains. Hsieh-Wilson's team is interested in how those sulfation patterns become altered, and how they might regulate biological processes such as neuroplasticity and social memory. This could also one day allow researchers to modulate these functions as a potential treatment for central nervous system injuries, neurodegenerative diseases or psychiatric disorders.

When the team deleted the Chst11 gene responsible for forming two major sulfation patterns on chondroitin sulfate in mice, defects formed in their perineuronal nets. However, the number of nets actually increased in the absence of the sulfation motifs, changing the types of synaptic connections between neurons. In addition, the mice were unable to recognize mice that they had previously been introduced to, which suggests that these patterns affect social memory.

Interestingly, these nets might be more dynamic than once thought -- they could be playing a role in both childhood and adulthood. When the researchers targeted Chst11 specifically in the brains of adult mice, they found the same effects on perineuronal nets and social memory. "That result suggests that it may be possible to manipulate these nets during adolescence or adulthood to potentially rewire or strengthen certain synaptic connections," says Hsieh-Wilson.

In other recent experiments, the team wanted to understand how GAGs and their sulfation patterns could affect axon regeneration, or the ability of neurons to rebuild themselves after injury. The researchers are now working to identify protein receptors that bind particular sulfation motifs. So far, they have found that specific motifs cause these receptors to cluster together at the cell's surface and inhibit regeneration. This process could be blocked to create tools or treatments to promote axon regeneration. Having more insight about this process could someday help repair damage caused by certain neurodegenerative diseases or strokes, Hsieh-Wilson says.

https://www.sciencedaily.com/releases/2023/08/230816114207.htm

Wildfires and farming activities may be top sources of air pollution linked to increased risk, cases of dementia

August 14, 2023

Science Daily/University of Michigan

No amount of air pollution is good for the brain, but wildfires and the emissions resulting from agriculture and farming in particular may pose especially toxic threats to cognitive health, according to new research from the University of Michigan.

Increasingly, evidence shows exposure to air pollution makes the brain susceptible to dementia. And now the findings of Boya Zhang and Sara Adar, environmental epidemiology researchers in U-M's School of Public Health, point to a strong likelihood that agriculture and wildfires, with their release of a range of harmful emissions at high concentrations, need to be more closely studied and monitored for their risks to public health, specifically dementia.

"We saw in our research that all airborne particles increased the risk of dementia but those generated by agricultural settings and wildfires seemed to be especially toxic for the brain," said Adar, associate chair of the Department of Epidemiology in the School of Public Health. She currently leads several large cohort studies on the impacts of exposures on cognitive aging and dementia.

"Our findings indicate that lowering levels of particulate matter air pollution, even in a relatively clean country like the United States, may reduce the number of people developing dementia in late life," Adar said.

Adar and Zhang's paper, "Comparison of Particulate Air Pollution From Different Emission Sources and Incident Dementia in the U.S.," appears today in the Journal of the American Medical Association's Internal Medicine.

Zhang, a research fellow who focuses on the effects of air pollution on cardiopulmonary disease and cognitive aging, said: "This work suggests that particulate matter air pollution from agriculture and wildfires might be more neurotoxic compared with other sources. However, more research is needed to confirm these effects, especially for these two sources which have received less attention in prior research."

"Given that the development of dementia could take a long time, this study mainly aimed to provide evidence for policymakers to reduce exposures to these sources of emissions," Zhang said.

The findings come as unusually poor air quality is regularly triggering alerts in the U.S. The alerts are aimed at protecting the public from the unseen, swirling mix of microscopic toxins in air pollution, specifically fine particulate matter or PM2.5. It is one of the most concerning elements of air pollution. At less than 2.5 microns in size, PM2.5 is less than the width of a human hair. Because it's so small, it can enter the brain through the nose directly or cross the blood-brain barrier in other ways. PM2.5 is also known to affect the lungs, heart, and in emerging research, the brain and cognitive function.

"These findings are quite timely given the increasing frequency of wildfire smoke in our

communities," Adar said. "Our data suggest that in addition to some of the more obvious health impacts of wildfire smoke like irritation to our throats and eyes along with breathing difficulties, high smoke days might also be taking a toll on our brains."

The record number of air quality alerts in the U.S. this year are due in large part to smoke from wildfires burning in Canada since May. The effect of wildfire is not new in the U.S., especially given the fires in the western part of the country.

Adar, a long-time environmental epidemiologist, said that wildfire smoke is becoming a more widespread stressor with many cities experiencing 30-plus days each year impacted by smoke. Given the extremely high levels of exposure to the public, wildfires are thought to contribute up to 25% of fine particulate matter exposures over a year across the U.S. and as much as 50% in some western regions of the country, Adar said.

"While individual wildfires may be short-lived, these events are becoming more frequent in our communities due to warmer temperatures, drier conditions, and longer fire seasons. As we've seen, wildfire smoke can also travel very far distances," Adar said.

Their findings are based on research into the development of dementia among nearly 30,000 adults from across the U.S. over an 18-year period. The data comes from the Health and Retirement Study, a nationally-representative collection of cohorts of older adults who have been followed since 1992. Pollution estimates in Adar and Zhang's study were based on home addresses of participants. Participants have been interviewed biennially about their cognition, overall health, and health behaviors until death or loss of contact for the survey.

They observed that higher levels of particulate matter air pollution, especially from agriculture and wildfires, were associated with greater risks of dementia. The findings could not be explained by other factors such as individual, neighborhood, socioeconomic status, occupation, or hometown or region of the country.

"With the knowledge of which sources are more toxic than others, it may be possible to design interventions for specific sources as a more effective way to decrease the burden of dementia," Zhang said.

Dementia is currently the seventh leading cause of death and one of the major causes of disability and dependency for older people, according to the World Health Organization.

The research specifically sought to test the hypothesis that a variation in emission sources could explain which are most toxic, but measuring the emissions with their distinct physical and chemical characteristics is challenging.

Past studies analyzing exposures to source specific fine particulate matter meant researchers mainly investigated relationships with the total mass of fine particulate matter in the air.

"In our study, we used a sophisticated prediction model that includes information about the chemical transformations and dispersion of pollution from different sources to estimate the levels of source-specific particulate matter air pollution at participants' residential addresses," Zhang said. "This approach is beneficial because it not only accounts for pollution directly emitted by a source but also pollution generated through reactions with other chemicals in the air."

Since the average level of exposure to PM2.5 for the people studied was less than the National Ambient Air Quality Standard, this is not just an issue of extreme pollution events, the researchers say, though it's clear that the air quality from wildfire events is worsening. This research suggests that it's not just sending people with respiratory ailments to the hospitals but there may also be longer lasting effects to the body. With the changing climate, it's likely that these threats to health will increase.

The study was funded by the National Institute of Environmental Health Sciences and the National Institute of Aging.

https://www.sciencedaily.com/releases/2023/08/230814121753.htm

Playing tackle football may increase the risk for Parkinson's disease

New study shows risk increases with more years of play, even in high school and college players

August 11, 2023

Science Daily/Boston University School of Medicine

Identification of risk factors for Parkinson's disease (PD) is essential for early diagnosis. Dating back to the 1920s, Parkinson's disease and parkinsonism -- an umbrella term that refers to motor symptoms found in Parkinson's disease and also other conditions -- have long been described in boxers. Repetitive head impacts from tackle football can also have long-term neurological consequences like chronic traumatic encephalopathy (CTE). But research on the association between participation in tackle football and PD is limited.

In the largest study to describe the association between participation in football and the odds for having a reported diagnosis of PD, researchers from the BU CTE Center used a large online data set of people concerned for having PD and found participants with a history of playing organized tackle football had a 61% increased odds of having a reported parkinsonism or PD diagnosis.

In this study, the researchers evaluated 1,875 sport participants -- 729 men who played football, predominantly at the amateur level, and 1,146 men who played non-football sports who served as the control group. Participants were enrolled in Fox Insight, a longitudinal online study of people with and without PD sponsored by The Michael J. Fox Foundation for Parkinson's Research.

Notably, researchers found a link between playing football and increased odds for having a parkinsonism or PD diagnosis even after accounting for known risk factors for PD. Additionally, the data revealed that players who had longer careers and played at higher levels of competition experienced increased odds for having a reported diagnosis of parkinsonism or PD. Football players who played at the college or professional level were at 2.93 increased odds for having a PD diagnosis compared with those who just played at the youth or high school level. Age of first exposure to football was not associated with odds for having a reported parkinsonism or PD diagnosis.

"Playing tackle football could be a contributing risk factor to PD, particularly among people already at risk due to other factors (e.g., family history). However, the reasons for this relationship are not clear and we also know that not everyone who plays tackle football will develop later-life neurological conditions, meaning many other risk factors are at play," says corresponding author Michael L. Alosco, PhD, associate professor of neurology at Boston University Chobanian & Avedisian School of Medicine.

The researchers also emphasized that they compared the football players to another group of athletes, a noteworthy strength of the study. Furthermore, most of the participants played tackle football only at the amateur level, which is contrast to most of the research to date that has focused on professional athletes.

"Previous research has focused on the association between American football and risk for CTE. However, similar to what has historically been seen in boxers, American football might also affect risk for other neurodegenerative conditions such as PD," says Hannah Bruce, MSc, first author and research specialist at Boston University Chobanian & Avedisian School of Medicine.

https://www.sciencedaily.com/releases/2023/08/230811115422.htm

Brain cells of males and females respond differently to chronic stress

August 9, 2023

Science Daily/Weizmann Institute of Science

Scientific excellence requires diversity -- research conducted by men and women, by people from different backgrounds and with varied worldviews. The need for diversity extends to scientific experiments themselves, but even today the vast majority of studies in the life sciences are done on male mice only, which could harm the findings, as well as our ability to extrapolate from them to humans. A new study by researchers from the Weizmann Institute of Science addresses this challenge, revealing in unprecedented detail how the brains of male and female mice respond differently to stress. In the study, published in Cell Reports, researchers from Prof. Alon Chen's joint laboratory at the Weizmann Institute and the Max Planck Institute of Psychiatry in Munich discovered that a subcategory of brain cells responds to stress in a totally different manner in males and females. The findings could lead to a better understanding of health conditions affected by chronic stress, such as anxiety, depression and even obesity and diabetes, and they could pave the way toward personalized therapies for these disorders.

Mental and physical disorders caused by chronic stress are constantly on the rise, putting a significant strain on society. They affect both men and women, but not necessarily in the same way. Although plenty of evidence suggests that men and women deal differently with stress, the causes of these differences are not yet fully understood, and in any event, personalized treatments for men and women are still beyond the reach of medicine. But researchers from Chen's laboratory, which specializes in studying the response to stress, hypothesized that innovative research methods could help to change the picture. Previous studies in other labs had uncovered certain sex differences in the response to stress, but those findings were obtained using research methods that could mask significant differences in the responses of specific cells or even entirely erase the roles played by relatively rare cells. Chen's laboratory, in contrast, uses advanced methods that allow scientists to analyze brain activity at an unprecedented resolution -- on the level of the individual cell -- and could therefore shed new light on the differences between the sexes.

"We turned the most sensitive research lens possible onto the area of the brain that acts as a central hub of the stress response in mammals, the paraventricular nucleus (PVN) of the hypothalamus," says Dr. Elena Brivio, who led the study. "By sequencing the RNA molecules in that part of the brain on the level of the individual cell, we were able to map the stress response in male and female mice along three main axes: how each cell type in that part of the brain responds to stress, how each cell type previously exposed to chronic stress responds to a new stress experience and how these responses differ between males and females."

The researchers mapped out gene expression in more than 35,000 individual cells, generating a huge amount of data that provides a picture of stress response that's unprecedented in its scope and in highlighting the differences between how males and females perceive and process stress. As part of the study, and in keeping with the principles of open-access science, the researchers decided to make the entire detailed mapping publicly available on a dedicated interactive website, which went live at the same time the study was published, providing other researchers with convenient, user-friendly access to the data. "The website will, for example, allow researchers who are focusing on a specific gene to see how that gene's expression changes in a certain cell type in response to stress, in males as well as females," Brivio explains.

The comprehensive mapping has already allowed the researchers to identify a long list of differences in gene expression -- between males and females, and between chronic and acute stress. The data showed, inter alia, that certain brain cells respond differently to stress in males and females: Some cells are more susceptible to stress in females and some to stress in males. The most significant difference was found in a type of brain cell called the oligodendrocyte -- a subtype of glial cell that provides support to nerve cells and plays an important role in regulating brain activity. In males, exposure to stress conditions, especially chronic stress, changed not only the gene expression in these cells and their interactions with surrounding nerve cells but also their very structure. In females, however, no significant change was observed in these cells, and they were not susceptible to stress exposure. "Neurons attract most of the scientific attention, but they only make up approximately a third of all cells in the brain. The method we implemented allows us to see a much richer and fuller picture, including all the cell types and their interactions in the part of the brain under study," says Dr. Juan Pablo Lopez, a former postdoctoral fellow in Chen's group and now the head of a research group at the Department of Neuroscience of the Karolinska Institute in Sweden.

Basic diversity

Until the 1980s, clinical trials of new drugs were conducted on men alone. The accepted view was that including women was unnecessary, and that it would only complicate the research, bringing into play new variables such as menstruation and hormonal changes. For the same reasons, preclinical studies avoided using female animals until very recently. But it's now known that the variability among male animals, on a molecular and behavioral level, is usually greater than among females, so there is no reason to suppose that females would complicate the experiments any more than males. Nonetheless, in basic research it's still common to conduct experiments only on males. "Our findings show that, when it comes to stress-related health conditions, from depression to diabetes, it's very important to take the sex variable into account, since it has a significant impact on how different brain cells respond to stress," Chen explains. "Even if a study does not specifically focus on the differences between males and females, it's essential to include female animals in the research, especially in neuroscience and behavioral science, just as it is important to implement the most sensitive research methods, in order to obtain as complete a picture of brain activity as possible," Brivio adds.

https://www.sciencedaily.com/releases/2023/08/230809130625.htm

How psychedelic drugs affect a rat's brain

August 9, 2023

Science Daily/Lund University

Researchers at Lund University have developed a technique for simultaneously measuring electrical signals from 128 areas of the brain in awake rats. They have then used the information to measure what happens to the neurons when the rats are given psychedelic drugs. The results show an unexpected and simultaneous synchronisation among neurons in several regions of the brain.

The idea that electrical oscillations in the brain could be used to teach us more about our experiences was conceived several years ago. Pär Halje and the research team was studying rats with Parkinson's disease that had problems with involuntary movements. The researchers discovered a tone -- an oscillation or wave in the electrical fields -- of 80 hertz in the brains of the rats with Parkinson's disease. It turned out that the wave was closely connected to the involuntary movements.

"A Polish researcher had observed similar waves after giving rats the anaesthetic ketamine. The ketamine was given at a low dose so that the rats were conscious, and the equivalent dose in a human causes psychedelic experiences. The waves they saw were in more cognitive regions of the brain than in the rats with Parkinson's, and the frequency was higher, but that still made us consider whether there were links between the two phenomena. Perhaps excessive brain waves in the motor regions of the brain cause motor symptoms, while excessive waves in cognitive regions give cognitive symptoms," says Pär Halje, researcher in neurophysiology at Lund University.

The research team that Pär Halje belongs to has developed a method that uses electrodes to simultaneously measure oscillations from 128 separate areas of the brain in awake rats. The electrical waves are caused by the cumulative activity in thousands of neurons, but the researchers also succeeded in isolating signals from individual neurons.

"For several of these areas, it is the first time anyone has successfully shown how individual neurons are affected by LSD in awake animals. When we gave the rats the psychedelic substances LSD and ketamine, the waves were clearly registered."

Collective wave patterns 

Despite ketamine and LSD affecting different receptors in the brain -- they have completely different ways into the nervous system -- they resulted in the same wave patterns even if the signals from individual cells differed. When the rats were given LSD, researchers saw that their neurons were inhibited -- they signalled less -- in all parts of the brain. Ketamine seemed to have a similar effect on the large neurons -- pyramidal cells -- which saw their expression inhibited, while interneurons, which are smaller neurons that are only collected locally in tissue, increased their signalling.

Pär Halje interprets the results seen in the study, which is published in Communication Biology, to mean that the wave phenomenon is connected to the psychedelic experience.

"Activity in the individual neurons caused by ketamine and LSD looks quite different, and as such cannot be directly linked to the psychedelic experience. Instead, it seems to be this distinctive wave phenomenon -- how the neurons behave collectively -- that is most strongly linked to the psychedelic experience."

Research model for psychoses

Even if what is happening in individual cells is interesting, Pär Halje argues that the whole is bigger and more exciting than the individual parts.

"The oscillations behave in a strange way. One might think that a strong wave starts somewhere, which then spreads to other parts of the brain. But instead, we see that the neurons' activity synchronises itself in a special way -- the waves in the brain go up and down essentially simultaneously in all parts of the brain where we are able to take measurements. This suggests that there are other ways in which the waves are communicated than through chemical synapses, which are relatively slow."

Pär Halje emphasises that it is difficult to know whether the waves cause hallucinations or are merely an indication of them. But, he argues, it opens up the possibility that this could be used as a research model for psychoses, where no good models exist today.

"Given how drastically a psychosis manifests itself, there ought to be a common pattern that we can measure. So far, we have not had that, but we now see a very specific oscillation pattern in rats that we are able to measure."

Can the waves reveal more about consciousness?

There is also a dream -- that the model will help us in the hunt for the mechanisms behind consciousness and that the measurements may be a way to study how consciousness is shaped.

"In light of the development of AI, it is becoming increasingly important to clarify what we mean by intelligence and what we mean by consciousness. Can self-awareness occur spontaneously, or is it something that needs to be built in? We do not know this today, because we do not know what the required ingredients for consciousness in our brains are. This is where it is exciting, the synchronised pattern we see, and whether this can help us to track down the neural foundations of consciousness," says Pär Halje.

https://www.sciencedaily.com/releases/2023/08/230809130726.htm

Perils of not being attractive or athletic in middle school

Growing unpopularity leads to more loneliness and alcohol misuse

August 10, 2023

Science Daily/Florida Atlantic University

Life is harder for adolescents who are not attractive or athletic. New research shows low attractive and low athletic youth became increasingly unpopular over the course of a school year, leading to subsequent increases in their loneliness and alcohol misuse. As their unpopularity grows, so do their problems. Put simply, the peer group punishes those who do not have highly valued traits such as being good-looking or being good at sports. Results also put to rest stereotypes about sex differences. The findings reveal a transformation in adolescent social culture such that the social penalties attached to being low in attractiveness or low in athleticism are no longer gender specific.

Despite the many changes in school culture since the 1960s, a new study reveals that some things never change: life is harder for middle school students who are not attractive and for those who are not athletic.

As children head back to school, the first-of-its-kind longitudinal study by Florida Atlantic University helps to explain why adolescents who lack traits valued by peers are at risk for adjustment difficulties.

Results, published in the Journal of Youth and Adolescence, show that low attractive youth and low athletic youth became increasingly unpopular over the course of a school year, leading to subsequent increases in their loneliness and alcohol misuse. Put simply, the peer group punishes those who do not have highly valued traits such as being good-looking or being good at sports.

The study put to rest stereotypes about sex differences in traits important for success with peers. For decades, it was assumed that not being athletic was particularly problematic for boys and that not being attractive was particularly problematic for girls.

The findings reveal a transformation in adolescent social culture such that the social penalties attached to being low in attractiveness or low in athleticism are no longer gender specific. Boys and girls did not differ in the extent to which unpopularity and adjustment problems flowed from low attractiveness and low athleticism. As their unpopularity grows, so do their problems.

"Children who lack the traits valued by their peers suffer from a host of adjustment difficulties, many of which stem from their deteriorating stature in the group," said Brett Laursen, Ph.D., senior author and a professor of psychology in FAU's Charles E. Schmidt College of Science. "Children who are not attractive and children who are not athletic become increasingly unpopular. Growing marginalization, in turn, precipitates loneliness and alcohol misuse. Growing unpopularity is the key to understanding why the unattractive and the unathletic develop behavior problems. Of those who began drinking to intoxication during the course of the school year, almost two-thirds were above average in unpopularity."

The dangers attached to stigmatized traits were comparable for boys and girls.

"Children who are not attractive and children who are not athletic become increasingly unpopular over time, suggesting that they must endure the indignities of powerlessness to remain attached to the peer group, a position that eventually takes a toll on individual well-being," said Mary Page James, first author and a Ph.D. student in FAU's Department of Psychology. "Being unattractive harms the popularity of boys as much as it does that of girls, and being unathletic is an important contributor to low popularity among girls, just as it is among boys. Despite widespread public messages about body acceptance, the adolescent social world is often still quite unforgiving."

The study included 580 middle school students who ranged in age from 10 to 13. Participants were asked to identify classmates who best fit the following descriptors: athletic ("good at sports"), attractive ("really good looking"), and unpopular ("unpopular"). They also described how often they felt lonely and how often they drank alcohol to the point of intoxication during the past month.

Replication is a strength of the study. The same pattern of associations emerged in a heterogeneous sample of youth from a large metropolitan area in Florida and from a homogeneous sample of youth from a small community in Lithuania.

Laursen, James and study co-authors offer several strategies to help children who lack these peer-valued traits:

• For teachers, consider altering classroom norms. It may be difficult to devalue physical appearance or athletic prowess given their prevalence in popular culture, but it may be possible to boost tolerance for those who are different or to emphasize the merits of other traits. A positive classroom climate also can buffer against loneliness for at-risk youth.

• Finally, parents should provide opportunities for children to establish and maintain close friendships with well-adjusted age-mates, because friends can mitigate against loneliness.

https://www.sciencedaily.com/releases/2023/08/230810110305.htm

Playing catch-up on weekends may not improve cardiovascular cost of sleep loss

August 9, 2023

Science Daily/Penn State

Whether it's work or play that prevents us from getting enough shut-eye during the week, assuming we can make up for it by sleeping in over the weekend is a mistake. New research led by Penn State reveals that cardiovascular health measures, including heart rate and blood pressure, worsen over the course of the week when sleep is restricted to five hours per night, and attempting to catch up on sleep over the weekend is insufficient to return these measures to normal.

"Only 65% of adults in the U.S. regularly sleep the recommended seven hours per night, and there's a lot of evidence suggesting that this lack of sleep is associated with cardiovascular disease in the long term," said Anne-Marie Chang, associate professor of biobehavioral health and co-author of the work, published in the journal Psychosomatic Medicine. "Our research reveals a potential mechanism for this longitudinal relationship, where enough successive hits to your cardiovascular health while you're young could make your heart more prone to cardiovascular disease in the future."

The team recruited 15 healthy men between the ages of 20 and 35 to participate in an 11-day inpatient sleep study. For the first three nights, the participants were allowed to sleep up to 10 hours per night to achieve a baseline sleep level. For the next five nights, the participants' sleep was restricted to five hours per night, followed by two recovery nights, in which they were again allowed to sleep up to 10 hours per night. To evaluate the effects of this sleep regime on cardiovascular health, the researchers measured the participants' resting heart rates and blood pressure every two hours during the day.

Chang explained that the team's study is unique because it measured heart rate and blood pressure multiple times throughout the day for the duration of the study, which enabled them to account for any effects that time of day might have on heart rate and blood pressure. For example, heart rate is naturally lower upon waking than later in the day, so measuring heart rate multiple times throughout the day can account for this difference.

The team, which included David Reichenberger, lead author and graduate student in biobehavioral health, Penn State, found that heart rate increased nearly one beat per minute (BPM) with each successive day of the study. Specifically, the average baseline heart rate was 69 BPM, while the average heart rate by the end of the study on the second day of recovery was nearly 78 BPM. Systolic blood pressure also increased by about 0.5 millimeters of mercury (mmHg) per day. The average baseline systolic blood pressure was 116 mmHg and was nearly 119.5 mmHg by the end of the recovery period.

"Both heart rate and systolic blood pressure increased with each successive day and did not return to baseline levels by the end of the recovery period," Reichenberger said. "So, despite having additional opportunity to rest, by the end of the weekend of the study, their cardiovascular systems still had not recovered."

Chang noted that longer periods of sleep recovery may be necessary to recover from multiple, consecutive nights of sleep loss.

"Sleep is a biological process, but it's also a behavioral one and one that we often have a lot of control over," Chang said. "Not only does sleep affect our cardiovascular health, but it also affects our weight, our mental health, our ability to focus and our ability to maintain healthy relationships with others, among many other things. As we learn more and more about the importance of sleep, and how it impacts everything in our lives, my hope is that it will become more of a focus for improving one's health."

Other Penn State authors on the paper include Stephen Strayer, former graduate student in neuroscience; Margeaux Schade, assistant research professor of biobehavioral health; and Orfeu Buxton, Elizabeth Fenton Susman Professor of Biobehavioral Health. Kelly Ness, postdoctoral fellow, University of Washington, and Gina Marie Mathew, postdoctoral associate, Stony Brook University, also are authors.

https://www.sciencedaily.com/releases/2023/08/230809130735.htm

Mothers experiencing depression can still thrive as parents

Researcher explores how external supports offset the risks to children's health posed by maternal depression

August 8, 2023

Science Daily/University of British Columbia Okanagan campus

The proverb "It takes a village to raise a child" takes on new significance when a mother of a child is experiencing depression.

"Being a mother with depression carries increased risks for a child's physical and psychological health," says Dr. Sarah Dow-Fleisner, Assistant Professor in the School of Social Work and Director of the Centre for the Study of Services to Children and Families at UBC Okanagan. "But it's not fated to be, especially if mothers have external supports."

Dr. Dow-Fleisner's findings, recently published in the Journal of Family Issues, have important implications for how social workers and clinical practitioners -- as well as families and communities -- can help.

While a lot of research focuses on the postpartum period during which the rate of depression among mothers is highest, Dr. Dow-Fleisner wanted to focus on depression occurring later in childhood. Her team used data from a large longitudinal US study to compare depressed and non-depressed mothers of nine-year-old children.

Her analyses revealed that mothers with depression were more likely to report parenting stress and less likely to view themselves as competent parents as compared to non-depressed mothers. They also reported engaging in more disciplinary tactics, including nonviolent tactics like taking away privileges as well as aggressive tactics like cursing or threatening the child. In terms of involvement, they were less likely to be involved at the child's school, such as attending an open house. However, they were equally likely to be involved in home activities, such as helping with homework.

"Furthermore, mothers with depression reported fewer interpersonal supports and community resources than mothers without depression," says Dr. Dow-Fleisner. "This is consistent with previous research."

Interpersonal supports refer to both emotional and material help from others, such as a relative providing advice or emergency childcare. Community resources refer to safety and neighbourhood cohesion. Neighbourhood cohesion measures the willingness of neighbours to help and the shared values of the neighbourhood, among other social and trust factors.

"Notably, those mothers with depression who reported higher levels of support and cohesion felt less stressed and more competent in their parenting," says Dr. Dow-Fleisner. "These positive perceptions translated to less psychological aggression-based discipline and more home and school involvement with their children."

These findings fit with a resilience perspective, whereby mothers facing adversity like depression can still thrive as parents -- especially when these protective factors are present.

"We want to help moms both address their depression and improve the child's health and wellbeing -- this is known as a two-generation approach," says Dr. Dow-Fleisner. "As mothers may not seek out help for their depression alone, a child health check-up in a primary care setting is a good opportunity to screen for maternal depression and provide support in identifying interpersonal supports and community resources."

Dr. Dow-Fleisner adds that supportive programs should go beyond addressing immediate parenting problems and instead build capacity. For example, a community-based parenting support group could help a mother to build a network of people who could provide material and emotional support as needed. Dr. Dow-Fleisner cites Mamas for Mamas as one such community-based group. Mamas for Mamas, with branches in Kelowna and Vancouver, builds community and provides material as well as other supports for mothers and other caregivers.

"Further funding of programs that empower mothers -- including those experiencing mental health concerns -- would go a long way in improving the health and wellbeing of children, mothers and families," says Dr. Dow-Fleisner.

https://www.sciencedaily.com/releases/2023/08/230808181910.htm       

Women who consumed sugar sweetened beverage daily had higher risk of developing liver cancer and chronic liver disease

Approximately 65% of adults in the United States consume sugar sweetened beverages daily

August 8, 2023

Science Daily/Mass General Brigham

Approximately 65% of adults in the United States consume sugar sweetened beverages daily. Chronic liver disease is a major cause of morbidity and mortality worldwide and can result in liver cancer and liver disease-related mortality. Researchers from Brigham and Women's Hospital, a founding member of the Mass General Brigham healthcare system, led one of the first studies to look at the association between intake of sugar-sweetened beverages, artificially sweetened beverages, and incidence of liver cancer and chronic liver disease mortality. Results are published in JAMA.

"To our knowledge, this is the first study to report an association between sugar sweetened beverage intake and chronic liver disease mortality," said first author Longgang Zhao, PhD, of the Brigham's Channing Division of Network Medicine. Zhao is a postdoctoral researcher who works with senior author Xuehong Zhang, MBBS, ScD, in the Channing Division. "Our findings, if confirmed, may pave the way to a public health strategy to reduce risk of liver disease based on data from a large and geographically diverse cohort."

This observational study included nearly 100,000 postmenopausal women from the large, prospective Women's Health Initiative study. Participants reported their usual soft drink, fruit drink (not including fruit juice) consumption, and then reported artificially sweetened beverage consumption after three years. Participants were followed for a median of more than 20 years. Researchers looked at self-reported liver cancer incidence and death due to chronic liver disease such as fibrosis, cirrhosis, or chronic hepatitis, which were further verified by medical records or the National Death Index.

A total of 98,786 postmenopausal women were included in the final analyses. The 6.8 percent of women who consumed one or more sugar-sweetened beverages daily had an 85 percent higher risk of liver cancer and 68 percent higher risk of chronic liver disease mortality compared to those who had fewer than three sugar sweetened beverages per month.

The authors note that the study was observational, and causality cannot be inferred, and relied on self-reported responses about intake, sugar content and outcomes. More studies are needed to validate this risk association and determine why the sugary drinks appeared to increase risk of liver cancer and disease. Furthermore, more research is needed to elucidate the potential mechanisms by integrating genetics, preclinical and experimental studies, and -omics data.

https://www.sciencedaily.com/releases/2023/08/230808110942.htm

People's everyday pleasures may improve cognitive arousal and performance

August 8, 2023

Science Daily/NYU Tandon School of Engineering

Developed over the past six years, MINDWATCH is an algorithm that analyzes a person's brain activity from data collected via any wearable device that can monitor electrodermal activity (EDA). This activity reflects changes in electrical conductance triggered by emotional stress, linked to sweat responses.

Listening to music and drinking coffee are the sorts of everyday pleasures that can impact a person's brain activity in ways that improve cognitive performance, including in tasks requiring concentration and memory.

That's a finding of a new NYU Tandon School of Engineering study involving MINDWATCH, a groundbreaking brain-monitoring technology.

Developed over the past six years by NYU Tandon's Biomedical Engineering Associate Professor Rose Faghih, MINDWATCH is an algorithm that analyzes a person's brain activity from data collected via any wearable device that can monitor electrodermal activity (EDA). This activity reflects changes in electrical conductance triggered by emotional stress, linked to sweat responses.

In this recent MINDWATCH study, published in Nature Scientific Reports, subjects wearing skin-monitoring wristbands and brain monitoring headbands completed cognitive tests while listening to music, drinking coffee and sniffing perfumes reflecting their individual preferences. They also completed those tests without any of those stimulants.

The MINDWATCH algorithm revealed that music and coffee measurably altered subjects' brain arousal, essentially putting them in a physiological "state of mind" that could modulate their performance in the working memory tasks they were performing.

Specifically, MINDWATCH determined the stimulants triggered increased "beta band" brain wave activity, a state associated with peak cognitive performance. Perfume had a modest positive effect as well, suggesting the need for further study.

"The pandemic has impacted the mental well-being of many people across the globe and now more than ever, there is a need to seamlessly monitor the negative impact of everyday stressors on one's cognitive function," said Faghih. "Right now MINDWATCH is still under development, but our eventual goal is that it will contribute to technology that could allow any person to monitor his or her own brain cognitive arousal in real time, detecting moments of acute stress or cognitive disengagement, for example. At those times, MINDWATCH could 'nudge' a person towards simple and safe interventions -- perhaps listening to music -- so they could get themselves into a brain state in which they feel better and perform job or school tasks more successfully."

The specific cognitive test used in this study -- a working memory task, called the n-back test -- involves presenting a sequence of stimuli (in this case, images or sounds) one by one and asking the subject to indicate whether the current stimulus matches the one presented "n" items back in the sequence. This study employed a 1-back test -- the participant responded "yes" when the current stimulus is the same as the one presented one item back -- and a more challenging 3-back test, asking the same for three items back.

Researchers tested three types of music -- energetic and relaxing music familiar to the subject, as well as novel AI-generated music that reflected the subject's tastes. Consistent with prior MINDWATCH research, familiar energetic music delivered bigger performance gains -- as measured by reaction times and correct answers -- than relaxing music. While AI-generated music produced the biggest gains among all three, further research is needed to confirm those results.

Drinking coffee led to notable but less-pronounced performance gains than music, and perfume had the most modest gains.

Performance gains under all stimulations tended to be higher on the 3-back tests, suggesting interventions may have the most profound effect when "cognitive load" is higher.

Ongoing experimentation by the MINDWATCH team will confirm the efficacy of the technology's ability to monitor brain activity consistently, and the general success of various interventions in modulating that brain activity. Determining a category of generally successful interventions does not mean that any individual person will find it works for them.

The research was performed as a part of Faghih's National Science Foundation CAREER award on the Multimodal Intelligent Noninvasive brain state Decoder for Wearable AdapTive Closed-loop arcHitectures (MINDWATCH) project. The study's diverse dataset is available to researchers, allowing additional research on the use of the safe interventions in this study to modulate brain cognitive states.

https://www.sciencedaily.com/releases/2023/08/230808151255.htm

Poor time management causes poor sleep for college students

August 8, 2023

Science Daily/University of Alabama in Tuscaloosa

A lack of time management skills, particularly in organization, can lead to poor sleep quality for college students according to research conducted at The University of Alabama.

Dr. Adam Knowlden, associate professor of health science with the UA College of Human Environmental Sciences, investigated time management and how it influences sleep health in full-time college students in the areas of setting goals and priorities, mechanics of time management, and preference for organization.

"College students tend to deal with lifestyle-related sleep problems," said Knowlden. "For example, balancing academic and social obligations can be challenging for college students. Stress and anxiety also impact college students and we know that stress can impact the sleep quality college students receive by causing insomnia."

According to Knowlden, more than 65% of college students describe their sleep quality as poor.

The study, which was recently published in the American Journal of Health Education, found the three factors associated with time management significantly influenced the overall sleep quality of college students. Knowlden reported that time management explained around 20% of the sleep quality outcomes measured.

"Among the three factors, having a preference for organization was the most crucial factor influencing sleep quality," said Knowlden. "This suggests that individuals who prioritize and maintain an organized environment tend to experience better sleep quality."

Knowlden, who has also conducted sleep health studies related to body composition and stress, says time management strategies should be learned and implemented prior to the start of the school year.

"We know that there is a tradition of college students staying up late, sometimes an entire 24 hours, to study or cram for exams," said Knowlden. "This is a tell-tale sign of the need for more focus on time management.

"However, until now, no study has looked specifically at time management to determine how much influence it has on the sleep of college students. We felt this was important to investigate because time management is something college students can work on improving."

Knowlden recommends blocking out eight to nine hours of sleep and making it the most important appointment of the day.

"We know that during sleep is when learning takes place," said Knowlden. "You can think of your mind like a computer. When we sleep, our brain is getting rid of information it doesn't need, and keeping information it does need. This is why students that prioritize sleep do better academically."

https://www.sciencedaily.com/releases/2023/08/230808151250.htm

Brain's 'appetite control center' different in people who are overweight or living with obesity

August 8, 2023

Science Daily/University of Cambridge

Cambridge scientists have shown that the hypothalamus, a key region of the brain involved in controlling appetite, is different in the brains of people who are overweight and people with obesity when compared to people who are a healthy weight.

Cambridge scientists have shown that the hypothalamus, a key region of the brain involved in controlling appetite, is different in the brains of people who are overweight and people with obesity when compared to people who are a healthy weight.

The researchers say their findings add further evidence to the relevance of brain structure to weight and food consumption.

Current estimations suggest that over 1.9 billion people worldwide are either overweight or obese. In the UK, according to the Office for Health Improvement & Disparities, almost two-thirds of adults are overweight or living with obesity. This increases an individual's risk of developing a number of health problems, including type 2 diabetes, heart disease and stroke, cancer and poorer mental health.

A large number of factors influence how much we eat and the types of food we eat, including our genetics, hormone regulation, and the environment in which we live. What happens in our brains to tell us that we are hungry or full is not entirely clear, though studies have shown that the hypothalamus, a small region of the brain about the size of an almond, plays an important role.

Dr Stephanie Brown from the Department of Psychiatry and Lucy Cavendish College, University of Cambridge, said: "Although we know the hypothalamus is important for determining how much we eat, we actually have very little direct information about this brain region in living humans. That's because it is very small and hard to make out on traditional MRI brain scans."

The majority of evidence for the role of the hypothalamus in appetite regulation comes from animal studies. These show that there are complex interacting pathways within the hypothalamus, with different cell populations acting together to tell us when we are hungry or full.

To get around this, Dr Brown and colleagues used an algorithm developed using machine learning to analyse MRI brain scans taken from 1,351 young adults across a range of BMI scores, looking for differences in the hypothalamus when comparing individuals who are underweight, healthy weight, overweight and living with obesity.

In a study published today in Neuroimage: Clinical, the team found that the overall volume of the hypothalamus was significantly larger in the overweight and obese groups of young adults. In fact, the team found a significant relationship between volume of the hypothalamus and body-mass index (BMI).

These volume differences were most apparent in those sub-regions of the hypothalamus that control appetite through the release of hormones to balance hunger and fullness.

While the precise significance of the finding is unclear -- including whether the structural changes are a cause or a consequence of the changes in body weight -- one possibility is that the change relates to inflammation. Previous animal studies have shown that a high fat diet can cause inflammation of the hypothalamus, which in turn prompts insulin resistance and obesity. In mice, just three days of a fat-rich diet is enough to cause this inflammation. Other studies have shown that this inflammation can raise the threshold at which animals are full -- in other words, they have to eat more food than usual to feel full.

Dr Brown, the study's first author, added: "If what we see in mice is the case in people, then eating a high-fat diet could trigger inflammation of our appetite control centre. Over time, this would change our ability to tell when we've eaten enough and to how our body processes blood sugar, leading us to put on weight."

Inflammation may explain why the hypothalamus is larger in these individuals, the team say. One suggestion is that the body reacts to inflammation by increasing the size of the brain's specialist immune cells, known as glia.

Professor Paul Fletcher, the study's senior author, from the Department of Psychiatry and Clare College, Cambridge, said: "The last two decades have given us important insights about appetite control and how it may be altered in obesity. Metabolic researchers at Cambridge have played a leading role in this.

"Our hope is that by taking this new approach to analysing brain scans in large datasets, we can further extend this work into humans, ultimately relating these subtle structural brain findings to changes in appetite and eating and generating a more comprehensive understanding of obesity."

The team say more research is needed to confirm whether increased volume in the hypothalamus is a result of being overweight or whether people with larger hypothalami are predisposed to eat more in the first place. It is also possible that these two factors interact with each other causing a feedback loop.

https://www.sciencedaily.com/releases/2023/08/230808110931.htm

How people feel about their sleep matters to their well-being

August 4, 2023

Science Daily/University of Warwick

How people feel about their sleep has a greater impact on their well-being than what sleep-tracking technology says about their sleep quality, research led by the University of Warwick has found.

Across a two-week period, over 100 participants aged 18-22 years were asked to keep a daily sleep diary about the previous night's sleep, including what time they went to bed, time they got ready to fall asleep, the amount of time it took them to fall asleep, what time they woke up, what time they got out of bed, and how satisfied they were with their sleep in general.

Five times throughout the following day, participants were asked to rate their positive and negative emotions and how satisfied they were with their life. Participants also wore an actigraph on their wrist which measures a person's movement, for the duration of the study, to estimate their sleep patterns and rest cycles.

Researchers compared the actigraphy data with the participants' perceptions of their sleep and how they felt throughout the following day. They wanted to find out how fluctuations from people's usual sleep patterns and quality are related to their mood and life satisfaction the next day.

Lead author Dr Anita Lenneis, from the University of Warwick's Department of Psychology, said: "Our results found that how young people evaluated their own sleep was consistently linked with how they felt about their well-being and life satisfaction.

"For example, when participants reported that they slept better than they normally did, they experienced more positive emotions and had a higher sense of life satisfaction the following day. However, the actigraphy-derived measure of sleep quality which is called sleep efficiency was not associated with next day's well-being at all.

"This suggests there is a difference between actigraphy-measured sleep efficiency and people's own perception of their sleep quality in how they link to people's evaluations of their well-being."

Professor Anu Realo, from the Department of Psychology at the University of Warwick added: "Our findings are consistent with our previous research that identified people's self-reported health, and not their actual health conditions, as the main factor associated with their subjective well-being and especially with life satisfaction.

"It's people's perception of their sleep quality and not the actigraphy-based sleep efficiency which matters to their well-being."

Overall, the study suggests that evaluating your sleep positively may contribute to a better mood on the next day.

"Even though a sleep tracking device might say that you slept poorly last night, your own perception of your sleep quality may be quite positive. And if you think that you slept well, it may help better your mood the next day," Dr Lenneis added.

"On the contrary, if a sleep tracker tells you that you slept well, but you did not experience the night as such, this information may help you to reassess how well you actually slept. A sleep tracker offers information about your sleep which is typically not accessible whilst being asleep. So, it may improve your subjective perception of last night's sleep and thereby your overall next day's well-being."

https://www.sciencedaily.com/releases/2023/08/230804123712.htm

A mother's diet can protect her grandchildren's brains: genetic model study

August 3, 2023

Science Daily/Monash University

Mothers who eat apples and herbs in early pregnancy could be protecting the brain health of their children and grandchildren, a Monash University study using genetic models has found.

The discovery is part of a project that found a mother's diet can affect not just her child's brain but also those of her grandchildren.

Published in Nature Cell Biology, the Monash Biomedicine Discovery Institute study found that certain foods could help protect against the deterioration of brain function.

More specifically, the study used roundworms (Caenorhabditis elegans) as the genetic model because many of their genes are also found conserved in humans, allowing insights into human cells.

The researchers found that a molecule present in apples and herbs (basil, rosemary, thyme, oregano, and sage) helped reduce the breakdown of communication cables needed for the brain to work properly.

Senior author Professor Roger Pocock and his team were investigating nerve cells in the brain that connect and communicate with each other through about 850,000 kilometres of cables called axons. For axons to function and survive, essential materials need to be transported along an internal structure that contains microtubules.

Professor Pocock explained that a malfunction that caused the axons to become fragile led to brain dysfunction and neurodegeneration.

He said his team used a genetic model with fragile axons that break as animals age. "We asked whether natural products found in the diet can stabilise these axons and prevent breakage," he explained.

"We identified a molecule found in apples and herbs (ursolic acid) that reduces axon fragility. How? We found that ursolic acid causes a gene to turn on that makes a specific type of fat. This particular fat also prevented axon fragility as animals age by improving axon transport and therefore its overall health."

Professor Pocock said this type of fat, known as a sphingolipid, had to travel from the mother's intestine, where food is digested, to eggs in the uterus for it to protect axons in the next generation. He said while the results were promising, they still need to be confirmed in humans.

"This is the first time that a lipid/fat has been shown to be inherited," he said. "Further, feeding the mother the sphingolipid protects the axons of two subsequent generations. This means a mother's diet can affect not just their offspring's brain but potentially subsequent generations. Our work supports a healthy diet during pregnancy for optimal brain development and health."

https://www.sciencedaily.com/releases/2023/08/230803213815.htm

How the gut signals to the brain

In a first, scientists define five types of colon neurons specialized for sending different signals to the brain

August 3, 2023

Science Daily/Harvard Medical School

Scientists define five types of colon neurons specialized for sending different signals to the brain.

The gut-brain connection is a complicated two-way signaling cascade that is responsible for keeping the digestive system working properly and can cause problems when it breaks down. A key part of that axis is the colon, which extracts water and nutrients from food and transports waste out of the body. This crucial organ is implicated in a range of gastrointestinal conditions, including constipation, diarrhea, pain, and inflammation.

Now, in a first, researchers at Harvard Medical School have defined five distinct subtypes of sensory neurons in the colon that carry signals to the brain.

In a new study, conducted in mice and published Aug. 3 in Cell, the researchers found that some neurons are dedicated to sensing gentle forces, such as substances moving through the colon, while others sense more intense ones, such as pain.

The researchers say that, if confirmed in humans, their findings could help scientists develop more effective therapies to treat conditions that arise when this colon-brain sensing system goes awry.

"Patients often complain about sensation and pain in the gastrointestinal system, yet we don't know a lot about the sensory neurons that innervate the gut and allow us to respond to different stimuli," said lead author Rachel Wolfson, a research fellow in neurobiology at HMS and a gastroenterology fellow at Massachusetts General Hospital.

From skin to colon

David Ginty and scientists in his lab have spent many years studying how sensory neurons in the skin communicate with the brain to form our sense of touch. They have developed precise genetic tools that label subtypes of sensory neurons and used these tools to uncover basic information about the structure, organization, and function of skin-sensing neurons.

Yet even as scientific knowledge about touch neurons has grown, very little research has focused on understanding the neurons in other parts of the body, including the gastrointestinal system.

"We've learned a lot about the neurons that go to the skin, but the properties of neurons that project to other organs like the colon have remained poorly understood," said Ginty, the Edward R. and Anne G. Lefler Professor of Neurobiology in the Blavatnik Institute at HMS and senior author on the new paper.

To tackle this understudied area, Ginty teamed up with Wolfson, a neurobiologist and clinical expert on the gastrointestinal system.

Wolfson took genetically labeled mouse models developed in the Ginty lab and repurposed them to study neurons in the colon. She discovered that five subtypes of sensory neurons in the skin are also found in the colon. However, colon and touch neurons had distinct shapes, and the subtypes of colon neurons also varied from each other in form.

"We know that form underlies function, so the fact that the colon neurons look different from each other made us think that they have different functions," Wolfson said.

To investigate function, Wolfson stretched the colon with a balloon -- mimicking naturally occurring distension -- and recorded activity in the distinct types of neurons.

Two types responded to gentle forces, similar to the slight stretching that might happen when digested food or stool moves through the colon. Two other types responded to intense forces, such as more extreme stretching. When Wolfson artificially activated these high-force neurons, the mice behaved as if they were in pain. When she removed the neuron with the highest force threshold, the pain response diminished. Triggering inflammation in the mice caused one of the pain-sensing neuron subtypes to become even more reactive.

Interestingly, these roles mapped onto the roles of neurons in the skin, suggesting that function may be conserved across organ systems.

The study provides critical insight into the basic neurobiological mechanisms of colon sensation.

"For the first time, we've been able to figure out the anatomy, physiology, and functions of neurons that innervate the colon," Ginty said.

Towards therapies for GI problems

In the short term, the researchers want to understand why colon neurons look different from their skin counterparts, and how these differences in form translate into differences in the way they behave.

"This finding is really provocative and provides a whole other direction for the work around understanding how the neurons convert mechanical forces into electrical signals, which is the currency of the nervous system," Ginty said.

In the longer term, Wolfson plans to study the neurons in other parts of the gastrointestinal tract. She also wants to explore how colon neurons respond to other stimuli such as toxins or a lack of blood flow, which can cause abdominal pain.

While the results would first have to be confirmed in humans, the researchers say their work could one day inform the development of better therapies for various gastrointestinal conditions.

"We've known about the innervation of the gut for 100 years, but modern neuroscience tools allow us to dig in and understand how it all works, and that's going to serve as a platform for therapeutic approaches to treating colon problems," Ginty said.

Targeting low-force neurons could be helpful for treating motility-related conditions like constipation and diarrhea, while targeting high-force neurons could be useful for treating pain that originates in the colon. Of particular interest is the neuron subtype that is sensitive to inflammation, which is a source of pain for patients with inflammatory bowel disease.

"Having a way to target these neurons to treat a patient's pain while we're getting the inflammation under control with anti-inflammatory medications is a huge therapeutic need," Wolfson said.

https://www.sciencedaily.com/releases/2023/08/230803113020.htm