Good attitudes about aging help seniors handle stress

August 3, 2016

Science Daily/North Carolina State University
Having a positive attitude about aging makes older adults more resilient when faced with stressful situations, new psychology research finds.

"There has been a lot of research on how older adults respond to stress, but the findings have been mixed: some studies have found that older adults are less resilient than younger adults at responding to stress; some have found that they're more resilient; and some have found no difference," says Jennifer Bellingtier, a Ph.D. student at NC State and lead author of a paper describing the work. "We wanted to see whether attitudes toward aging could account for this disparity in research findings. In other words, are older adults with positive attitudes about aging more resilient than older adults with negative attitudes?"

The answer is yes.

For the study, researchers had 43 adults between the ages of 60 and 96 fill out a daily questionnaire for eight consecutive days. At the beginning of the study, participants were asked about their attitudes toward aging. For example, participants were asked if they felt they were as useful now as they had been when they were younger, and whether they were as happy as when they were younger.

The daily questionnaire asked participants about any stress they'd experienced that day, as well as the extent to which they experienced negative emotions, such as fear, irritability or distress.

The researchers also accounted for the personality of study participants. Were they optimistic and upbeat about everything, or are there benefits tied specifically to an individual's attitudes about aging?

"We found that people in the study who had more positive attitudes toward aging were more resilient in response to stress -- meaning that there wasn't a significant increase in negative emotions," Bellingtier says. "Meanwhile, study participants with more negative attitudes toward aging showed a sharp increase in negative emotional affect on stressful days."

"This tells us that the way we think about aging has very real consequences for how we respond to difficult situations when we're older," says Shevaun Neupert, an associate professor of psychology at NC State and senior author on the paper. "That affects our quality of life and may also have health ramifications. For example, more adverse emotional responses to stress have been associated with increased cardiovascular health risks."

"Our findings are likely applicable to other Americans, but it's not clear to what extent the findings would be relevant elsewhere," Bellingtier says. "Attitudes toward aging vary widely across cultures, and more work would need to be done to determine the importance of aging attitudes in other settings."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/08/160803084145.htm

Volunteering later in life can enhance mental health and wellbeing

August 9, 2016

Science Daily/University of Southampton
Becoming a volunteer later on in life can result in good mental health and wellbeing, according to researchers. However, their study found these effects did not apply before the age of 40, suggesting that the association with volunteering may be stronger at certain points of the life course.

However, the study which is published in the BMJ Open online, found these effects did not apply before the age of 40, suggesting that the association with volunteering may be stronger at certain points of the life course. The results also point to the need for further efforts to engage middle aged and older people in volunteering activities.

Researchers from the Southampton Statistical Sciences Research Institute and Birmingham's Third Sector Research Centre reviewed over 66,000 responses by British adults to questions posed through the British Household Panel Survey (BHPS), now part of the UK Household Longitudinal Study called Understanding Society.

The original Survey, which ran between 1991-2008, asked a range of questions on leisure time activities including the extent of formal volunteering. The Survey also included a validated proxy indicating mental health/emotional wellbeing known as GHQ-12.

Around 21% of respondents said they had carried out some kind of formal volunteering activity with women tending to volunteer more than men.

Across the entire sample, the average GHQ score was the best (lowest) among those who were frequent volunteers and worst (highest) among those who never volunteered.

When age was factored in by the research team, the positive association between volunteering and good mental health and emotional wellbeing became apparent at around the age of 40 and continued up into old age (80+).

"Voluntary action might provide those groups with greater opportunities for beneficial activities and social contacts, which in turn may have protective effects on health status," said Dr Faiza Tabassum, Visiting Research Fellow at the University of Southampton. "Particularly, with the ageing of the population, it is imperative to develop effective health promotion for this last third of life, so that those living longer are healthier."

The researchers found that those who had never volunteered had lower levels of emotional wellbeing, starting at midlife and continuing into old age compared with those who did volunteer.

Previous research has indicated that volunteering in older age is associated with better mental and physical health, but it was unclear whether this extends to other age groups until now.

Dr Tabassum added: "Volunteering may also provide a sense of purpose, particularly for those people who have lost their earnings, because regular volunteering helps contribute to the maintenance of social networks, and this is especially the case for older people who often live in isolation."

The findings held true even after taking account of a range of potentially influential factors, including marital status, educational attainment, and social class. The researchers were not able to gauge the extent of 'informal' volunteering, such as helping out neighbours so couldn't capture the full spectrum of voluntary activities.

"Precisely how opportunities for engagement in volunteering can be provided and sustained is a considerable challenge at the present time, because of the pressures of austerity, while the distribution of voluntary organisations means that opportunities to participate are not always available everywhere," said Professor John Mohan, Deputy Director of the Third Sector Research Centre at the University of Birmingham. "But this study does suggest that we should pay attention to the diversity of experience of people across their life course, and not just uncritically assume that volunteering has benefits for everyone, everywhere."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/08/160809122133.htm

Midlife physical activity is associated with better cognition in old age

September 9, 2016

Science Daily/Helsingin yliopisto (University of Helsinki)
Moderately vigorous physical activity -- for example, more strenuous than walking -- has been found to be associated with better cognition in a 25-year follow-up, a new study of 3050 twins finds.

A long-term follow-up study of 3050 twins from the Finnish Twin Cohort has shown that midlife, moderately vigorous physical activity is associated with better cognition at old age. The association was statistically independent of midlife hypertension, smoking, education level, sex, obesity and binge drinking. "This suggests that the beneficial influence of physical activity on the brain and cognition is not solely based on decreasing vascular risk factors," says researcher Paula Iso-Markku from the University of Helsinki.

The association was studied first in all individuals of the cohort, and then by comparing later cognition in pairs where one twin was more physically active than the other.

Increasing the volume of physical activity was not, however, associated with increased memory-protecting benefits. Instead, quite a moderate amount of physical activity was found to be sufficient for memory-protecting benefits, and only the most inactive group of twins stood out with a significantly higher risk for cognitive impairment.

"Overall, the study shows that moderately vigorous physical activity, meaning more strenuous than walking, is associated with better cognition after an average of 25 years," states Professor Urho Kujala from the University of Jyväskylä.

This finding is in accordance with earlier animal model studies, which have shown that physical activity increases the amount of growth factors in the brain and improves synaptic plasticity.

The prevalence of dementia has increased with aging populations both in Finland and globally. Although the incidence of dementia seems to have decreased in less senior generations, the total prevalence of dementia is still expected to rise. No cure for dementia exists, but during the last decade research has produced an abundance of new information on dementia prevention. The traditional vascular risk factors (elevated blood pressure, hypercholesterolemia, obesity, diabetes and lack of exercise) have also been associated with dementia risk. "However, few long-term, high-quality, follow-up studies on physical activity and cognition have been published, and it has remained unclear what type and amount of exercise is needed to safeguard cognition," Iso-Markku says.

The study, published in the Journal of Alzheimer's Disease, was conducted by scientists at the universities of Helsinki, Jyväskylä and Turku. The twins provided information on physical activity through questionnaire surveys from 1975 and 1981 (mean age in 1981: 49 years), while cognition was assessed by validated telephone interviews conducted between 1999 and 2015.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/09/160909095045.htm

How our brain slows down the effects of aging

September 14, 2016
Science Daily/Ruhr-Universitaet-Bochum
The older we get, the more difficult it becomes to put the world around us in order. Yet, our brain develops remarkable strategies to slow down the effects of aging.
https://images.sciencedaily.com/2016/09/160914090317_1_540x360.jpg
Older people pay more attention to the details and look more closely than younger people.
Credit: © WONG SZE FEI / Fotolia

In order to process the information that we receive every day, we build categories into which we sort everything that makes up the world around us. Neuroscientists from Ruhr-Universität Bochum (RUB) found out: the way we categorise things changes throughout our lifetimes. Their research results were now published in the journal Neuropsychologia.

The team surrounding Sabrina Schenk and Prof. Dr. Boris Suchan observed young and older people during a categorisation task. The participants of the study were asked to sort circles with varying colour combinations into one of two categories. Some of the circles were very similar to each other; others were distinctly different. To which category the circles belonged was indicated by a feedback during the test.

Brain waves and gaze direction offer insights

The scientists not only documented the test subjects' answers, they also recorded their brain waves via an EEG and used an eye tracker to trace their line of vision. The results showed that both young and older subjects had no difficulties categorising the similar looking circles -- the learning mechanism of both groups were comparable. It was only in the later stages of the experiment, when distinct looking circles where shown, that differences between the test groups became apparent. Older subjects found it more difficult to categorise these exceptions than their younger counterparts.

Brain compensates with attentiveness

"There are two main strategies which we use to categorise things. While we perceive similar looking members of a category holistically, we must specifically learn exceptions and memorise them," Schenk explains. "Older people find it harder to switch from one strategy to the other." But measurements of brain waves also showed that the elderly develop a particular selective attentiveness.

To put it simply: they pay more attention to the details and look more closely than younger people. This is also confirmed by the eye tracker, which records in which direction the participants are looking. "To a certain extent, the brain is able to slow down negative effects of aging by increasing its level of attentiveness," summarises Schenk.
 

Further studies with gamers

A computer simulation at Canada's University of Western Ontario has confirmed the results of the scientists in Bochum. In a next step the RUB team would like to test people whose attention level has been especially trained, like that of avid computer players. If these gamers do particularly well in the categorisation task, then the results may help the elderly specifically train their attentiveness.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/09/160914090317.htm

Prevalence of mental disorders among older people is greater than previously assumed

September 15, 2016

Science Daily/Alpen-Adria-Universität Klagenfurt | Graz | Wien
Previous studies have largely assumed that the prevalence of mental disorders declines with old age. The results of a new large-scale study with innovative diagnostic methods conducted in six European countries reveal that, considering the previous year retrospectively, approximately one third of the respondents in the age group between 65 and 85 had suffered from a mental disorder, and roughly one quarter were mentally ill at the time of the interviews.

"We started with the assumption that valid diagnostic methods for adults are less suitable for the diagnosis of mental disorders in elderly people," lead scientist Professor Sylke Andreas (Department of Psychology at the Alpen-Adria-Universität) explains. She coordinated the investigation together with Professor Martin Härter, Dr. Jana Volkert and Professor Holger Schulz (Department of Medical Psychology at the University Medical Center Hamburg-Eppendorf). When confronted with traditional diagnostic tools, older people soon struggle to remain attentive. What is more, the questions included in established diagnostic methods are often rather long and complicated, further adding to the difficulties experienced by the elderly.

As a first step, the research team, comprising scientists from Spain, Great Britain, Germany, Italy, Israel and Switzerland, developed a new diagnostic tool in the shape of a computer-based interview with simplified sentences. Subsequently, this method was used to examine 3,100 elderly people (65 to 85 years old) in Spain, Great Britain, Germany, Italy, Israel and Switzerland.

The results revealed a prevalence of mental disorders in older people that is significantly higher than had been previously assumed: At the time of the interviews, one third of the respondents had suffered from a mental disorder within the previous year (one year prevalence) and one quarter of the respondents was diagnosed with a current mental disorder. The most common disorders experienced by the respondents in the preceding twelve months were anxiety disorders (17 per cent) and depressive disorders (14 per cent).

According to Sylke Andreas, these results are cause for grave concern, particularly when considered against the background of the health services provided so far. "We need better and more reliable methods to determine whether an older person is suffering from a mental disorder. This goes hand in hand with the urgent need to establish a range of psychotherapeutic services for the elderly, which has been almost entirely absent to date."
Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/09/160915085549.htm

Do older people take fewer risks?

October 4, 2016
Science Daily/Universität Basel
Whether and how risk-taking propensity varies over a person’s life span depends in part on how risk taking is measured, research concludes. When subjects are asked how they assess their risk propensity, a clear reduction with age is the result. However, this reduction is not necessarily observed for specific risk-taking tasks. Depending on the type of task set, the propensity measured in older people can be unchanged, lower or higher. These heterogeneous results could be caused by an age-related functional change in the brain.

Cognitive and decision scientists from the University of Basel carried out research into whether we engage in more or less risk-taking behavior as we get older and into the biological foundations that influence our decision making. The researchers examined, inter alia, the influence of the measurement instruments used on the observed age-related changes in risk-taking behavior. Two studies were carried out: in the first, the researchers collected data on self-assessment and behavior in risk-taking tasks from more than 1,000 subjects aged between 18 and 90. The second study used magnetic resonance imaging to compare the brain function of younger and older adults as they solved risk-taking tasks.

Self-report and behavior do not always converge

The results of the first study, published in the journal Psychology and Aging, show that based on self-reports, risk-taking propensity decreases over the subject's life span, but can be observed both to decrease and stay the same, or even increase slightly, in a variety of risk-taking tasks. The study found that different measurement instruments sometimes result in different risk profiles.

As a potential cause for these heterogeneous results, the researchers cite the different cognitive requirements of the tasks. Demanding tasks presented a greater challenge to older people than younger people. One example of a more complex task used in both studies was the "Balloon Analogue Risk Task," which involved inflating virtual balloons, with points awarded for each pump stroke. The larger the balloon, the more points are awarded and the higher the subject's winnings at the end of the task. If the balloon is inflated too far, it bursts and all the points earned are lost. The balloons burst at various points, which are, of course, unknown to the subjects. Successful completion of the balloon task requires the extraction and integration of various pieces of information.

Older people may find it harder to cope with these demands, causing them to resort, for example, to less profitable, risk-averse behavior in the balloon task. Depending on the task structure and requirements, the risk propensity observed in older subjects may remain the same, decrease or even increase.

Neurological foundations of decision making

In order to better understand the biological foundations of these processes, in a second study the researchers compared the neural functional profiles observed in the Balloon Analogue Risk Task for groups of 26 younger and 27 older subjects. In collaboration with Chinese scientists, they identified age-related functional changes in a certain region of the brain as a potential contributing factor to the observed heterogeneity in risk tasks. As the researchers report in the journal Frontiers in Aging Neuroscience, age does not seem to substantially influence the processing of risk, reward or loss per se, but rather to affect the way they are integrated into a decision signal.

In summary, to ask whether older people take fewer risks than younger people or not is perhaps misguided. Instead, what transpires from these two studies is that risk-taking propensity and changes therein depend on the complexity of the task. The processing and integration of large quantities of information is of vital importance, in particular in terms of financial and health-related decisions. The authors therefore recommend age-appropriate structuring and communication of information in order to ensure that the preferences of older people do not result merely as an effect of the measurement.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161004085421.htm

Brain training may help keep seniors on the road

October 10, 2016

Science Daily/Penn State University
Older adults who participate in training designed to improve cognitive ability are more likely to continue driving over the next 10 years than those who do not, according to health researchers.

"Driving cessation has huge ramifications for seniors," said Lesley A. Ross, Penn State assistant professor of human development and family studies. "It signals an end to freedom, acting as a concrete acknowledgement that you're declining."

Ross and colleagues studied the effects of three different cognitive training programs -- reasoning, memory and divided attention -- on driving cessation in older adults.

The researchers found that the participants who completed either the reasoning or divided-attention training were between 55 and 49 percent more likely to still be drivers 10 years after the study began than those who did not receive training. Randomly selected participants who received additional divided-attention training were 70 percent more likely to report still driving after 10 years. The researchers report their results in the current issue of The Gerontologist.

Over 2,000 adults aged 65 or older were randomly assigned to one of four groups -- reasoning, memory, divided attention training or no training. All of the participants were drivers at the start of the program and were in good health. The participants were evaluated seven times over the course of 10 years.

Participants randomized to one of the three types of interventions each received 10 hours of cognitive training. Following the 10 hours of training, participants were randomly selected to receive additional "booster" training.

Both the reasoning and the memory training used pencil and paper activities, while the divided-attention training used a computer program. The reasoning exercise included brain teasers and taught the participants problem-solving strategies, while the memory training involved categorization of lists of words to help with everyday life, such as a list of errands or a grocery list.

The divided-attention, or speed of processing, training used perceptual exercises where participants were shown several objects on a screen at once for a very brief period of time and then asked questions about what they had seen. This program was adaptive, becoming more difficult after the first five exercises were completed.

Ross and colleagues plan to continue to study the effect of cognitive training, including the introduction of Xbox Kinect, a computer gaming platform, into future research.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161010143842.htm

Substance with the potential to postpone aging

October 14, 2016

Science Daily/University of Copenhagen The Faculty of Health and Medical Sciences
The coenzyme NAD+ plays a main role in aging processes. In mice and roundworm adding the substance can both extend life and postpone the onset of aging processes. New research shows that this new knowledge will eventually be able to help patients with Alzheimer's and Parkinson's disease.
https://images.sciencedaily.com/2016/10/161014152322_1_540x360.jpg
As we live longer and longer, a lot of people are occupied with their state of health and, not least, quality of life in old age. Therefore, researchers all over the world are trying to understand aging mechanisms, as this knowledge may eventually help to postpone physical aging and extend life. None of the existing explanations of physical aging are able to explain all the biological aspects of human aging.
Credit: Image courtesy of University of Copenhagen The Faculty of Health and Medical Sciences
    
As we live longer and longer, a lot of people are occupied with their state of health and, not least, quality of life in old age. Therefore, researchers all over the world are trying to understand aging mechanisms, as this knowledge may eventually help to postpone physical aging and extend life. None of the existing explanations of physical aging are able to explain all the biological aspects of human aging.

Substance Bridges Gap

Previous research has shown that a main process in aging is the capacity of the cells to keep our genes, our DNA, more or less intact. However, changes in the cells' power stations, the mitochondria, also affect aging processes. An international team of researchers from the Center for Healthy Aging at the University of Copenhagen and the National Institute of Health in the United States has shown that the substance NAD+ bridges the gap between two main aging theories -- repairs to the DNA and poor functioning mitochondria. The results have just been published in the leading journal Cell Metabolism.

'Our new study shows an age-dependent decrease in the level of NAD+, and this decrease is far greater for organisms with early aging and a lack of DNA repairs. We were surprised to see that adding NAD+ postponed both the aging processes of the cells and extended life in worms and in a mouse model', says Professor Vilhelm Bohr from the Center for Healthy Aging and the National Institute of Health.

The researchers have bred mice and roundworm with the illness Ataxia telangiectasia, A-T, for the purpose of the study. In A-T patients the part of the brain that is responsible for coordination gradually degenerates, DNA repairs are lacking, and they experience other symptoms characteristic of early aging.

Adding NAD+ Postpones Aging

'We know from previous studies that a drop in the level of NAD+ results in metabolism errors, neurodegeneration and aging, but the underlying mechanisms remain unclear to us. Our new study stresses that the substance NAD+ plays a main role both in maintaining the health of the cells' power stations and in their capacity for repairing the genes', says Professor Vilhelm Bohr.

The study also indicates that damage to the DNA can result in poor functioning mitochondria, and that this can lead to increasing neurodegeneration in A-T patients. Adding the substance NAD+ can stop the damage to the mitochondria.

Help for Patients in the Future

Even though the researchers have only examined the effect of the substance on model organisms and not administered the substance to patients, they expect to see the same effect in humans, as the cell repair mechanisms are universal for the cells of all living organisms. Understanding the universal mechanisms at cell level is key to understanding human aging and why we become more susceptible to illness as we grow older. Hopefully, this new knowledge will be able to help postpone physical aging processes and prevent illnesses such as Alzheimer's and Parkinson's disease.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/10/161014152322.htm

The aging brain benefits from distraction

November 15, 2016

Science Daily/Cell Press
As you age, you may find it more difficult to focus on certain tasks. But while distractions can be frustrating, they may not be as bad as we think. In a new report, researchers suggest that there may be some benefits to reduced focus, especially in people over 50. Using behavioral studies and neuroimaging evidence, the researchers discuss how being easily distracted can help adults with, for example, problem solving and learning new information.
https://images.sciencedaily.com/2016/11/161115150726_1_540x360.jpg
This figure shows the relationship between task performance and level of cognitive control.
Credit: Amer, Campbell, Hasher/Trends in Cognitive Sciences 2016

"Different types of tasks benefit from a more broad focus of attention, and this is usually seen in tasks that involve thinking creatively or using information that was previously irrelevant," says first author Tarek Amer, a psychology Ph.D. candidate at the University of Toronto and a graduate student at the Rotman Research Institute. "The literature gives us the impression that older adults are essentially doomed as their cognitive abilities decrease, when, in reality, many older adults get along just fine in their day-to-day lives, and we think that shows that aging adults don't always need to have high cognitive control."

When people have high cognitive control, they are able to maintain their focused attention and ignore distractions to get things done. But Amer and his colleagues found that people with reduced cognitive control had an easier time thinking of creative solutions to problems, and they were better at noticing patterns in the world around them. These findings also indicated that older adults could outperform their younger counterparts on certain problem-solving tasks, as they were able to broaden their attention more easily. Additionally, people didn't require high levels of cognitive control for inherent, day-to-day tasks, like walking down the street or learning new information.

In order to explore the benefits of cognitive control, many lab-based behavioral experiments require participants to complete a specific set of tasks, limiting the role of distraction. But the researchers say these experiments have shortcomings, as they don't explore situations when distractions and reduced cognitive control could be helpful, making the conclusions fairly one sided.

"Many of the tasks that we study in classic cognitive psychology are tasks that require high cognitive control, but these assigned tasks might not accurately mirror what people do in the real world because they limit distractions," says co-author Lynn Hasher, a professor of psychology at the University of Toronto and the Rotman Research Institute. "But a distraction in one setting can actually be useful information in another setting, and the more information you have, the better able you're going to be to address a current problem."

Amer and his colleagues hope to use this information to determine exactly what tasks can benefit from reduced control in order to better simulate these experiences in a lab. Although they also hope to expand the research beyond the aging population to examine how distractions can be beneficial for people with a range of cognitive impairments, for now they recognize that this understanding of cognitive control is a step closer to understanding the aging brain.

"There is a question about what really sustains performance in old age, and it's clear that working memory alone cannot provide us with the answer to that question," says Hasher. "But we think it's possible that studying reduced cognitive control can help us understand how older adults can still perform independently and successfully in their lives."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/11/161115150726.htm

Helping pays off: People who care for others live longer

December 22, 2016
Science Daily/Universität Basel
Older people who help and support others live longer, a new study has concluded. The results of these findings show that this kind of caregiving can have a positive effect on the mortality of the carers.
https://images.sciencedaily.com/2016/12/161222094834_1_540x360.jpg
Older people who help and support others live longer.
Credit: © aytuncoylum / Fotolia

Older people who help and support others are also doing themselves a favor. An international research team has found that grandparents who care for their grandchildren on average live longer than grandparents who do not. The researchers conducted survival analyses of over 500 people aged between 70 and 103 years, drawing on data from the Berlin Aging Study collected between 1990 and 2009.

In contrast to most previous studies on the topic, the researchers deliberately did not include grandparents who were primary or custodial caregivers. Instead, they compared grandparents who provided occasional childcare with grandparents who did not, as well as with older adults who did not have children or grandchildren but who provided care for others in their social network.

Emotional support

The results of their analyses show that this kind of caregiving can have a positive effect on the mortality of the carers. Half of the grandparents who took care of their grandchildren were still alive about ten years after the first interview in 1990. The same applied to participants who did not have grandchildren, but who supported their children -- for example, by helping with housework. In contrast, about half of those who did not help others died within five years.

The researchers were also able to show that this positive effect of caregiving on mortality was not limited to help and caregiving within the family. The data analysis showed that childless older adults who provided others with emotional support, for example, also benefited. Half of these helpers lived for another seven years, whereas non-helpers on average lived for only another four years.
 

Too intense involvement causes stress

"But helping shouldn't be misunderstood as a panacea for a longer life," says Ralph Hertwig, Director of the Center for Adaptive Rationality at the Max Planck Institute for Human Development. "A moderate level of caregiving involvement does seem to have positive effects on health. But previous studies have shown that more intense involvement causes stress, which has negative effects on physical and mental health," says Hertwig. As it is not customary for grandparents in Germany and Switzerland to take custodial care of their grandchildren, primary and custodial caregivers were not included in the analyses.

The researchers think that prosocial behavior was originally rooted in the family. "It seems plausible that the development of parents' and grandparents' prosocial behavior toward their kin left its imprint on the human body in terms of a neural and hormonal system that subsequently laid the foundation for the evolution of cooperation and altruistic behavior towards non-kin," says first author Sonja Hilbrand, doctoral student in the Department of Psychology at the University of Basel.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/12/161222094834.htm
 

With beetroot juice before exercise, aging brains look 'younger'

April 19, 2017

Science Daily/Wake Forest University
Drinking a beetroot juice supplement before working out makes the brain of older adults perform more efficiently, mirroring the operations of a younger brain, according to a new study.

"We knew, going in, that a number of studies had shown that exercise has positive effects on the brain," said W. Jack Rejeski, study co-author. "But what we showed in this brief training study of hypertensive older adults was that, as compared to exercise alone, adding a beet root juice supplement to exercise resulted in brain connectivity that closely resembles what you see in younger adults."

While continued work in this area is needed to replicate and extend these exciting findings, they do suggest that what we eat as we age could be critically important to the maintenance of our brain health and functional independence.

Rejeski is Thurman D. Kitchin Professor and Director of the Behavioral Medicine Laboratory in the Department of Health & Exercise Science. The study, "Beet Root Juice: An Ergogenic Aid for Exercise and the Aging Brain," was published in the peer-reviewed Journals of Gerontology: Medical Sciences. One of his former undergraduate students, Meredith Petrie, was the lead author on the paper.

This is the first experiment to test the combined effects of exercise and beetroot juice on functional brain networks in the motor cortex and secondary connections between the motor cortex and the insula, which support mobility, Rejeski said.

The study included 26 men and women age 55 and older who did not exercise, had high blood pressure, and took no more than two medications for high blood pressure. Three times a week for six weeks, they drank a beetroot juice supplement called Beet-It Sport Shot one hour before a moderately intense, 50-minute walk on a treadmill. Half the participants received Beet-It containing 560 mg of nitrate; the others received a placebo Beet-It with very little nitrate.

Beets contain a high level of dietary nitrate, which is converted to nitrite and then nitric oxide (NO) when consumed. NO increases blood flow in the body, and multiple studies have shown it can improve exercise performance in people of various ages.

"Nitric oxide is a really powerful molecule. It goes to the areas of the body which are hypoxic, or needing oxygen, and the brain is a heavy feeder of oxygen in your body," said Rejeski.

When you exercise, the brain's somatomotor cortex, which processes information from the muscles, sorts out the cues coming in from the body. Exercise should strengthen the somatomotor cortex.

So, combining beetroot juice with exercise delivers even more oxygen to the brain and creates an excellent environment for strengthening the somatomotor cortex. Post-exercise analysis showed that, although the study groups has similar levels of nitrate and nitrite in the blood before drinking the juice, the beetroot juice group had much higher levels of nitrate and nitrite than the placebo group after exercise.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/04/170419091619.htm

Want to stay mentally healthy in older age?

April 20, 2017

Science Daily/University of Exeter
Stimulating the brain by taking on leadership roles at work or staying on in education help people stay mentally healthy in later life, according to new research.

The large-scale investigation published in the journal PLOS Medicine and led by the University of Exeter, used data from more than 2,000 mentally fit people over the age of 65, examined the theory that experiences in early or mid life which challenge the brain make people more resilient to changes resulting from age or illness -- they have higher "cognitive reserve."

The analysis, funded by the Economic and Social Research Council (ESRC) found that people with higher levels of reserve are more likely to stay mentally fit for longer, making the brain more resilient to illnesses such as dementia.

The research team included collaborators from the universities of Bangor, Newcastle and Cambridge.

Linda Clare, Professor of Clinical Psychology of Ageing and Dementia at the University of Exeter, said: "Losing mental ability is not inevitable in later life. We know that we can all take action to increase our chances of maintaining our own mental health, through healthy living and engaging in stimulating activities. It's important that we understand how and why this occurs, so we can give people meaningful and effective measures to take control of living full and active lives into older age.

"People who engage in stimulating activity which stretches the brain, challenging it to use different strategies that exercise a variety of networks, have higher 'Cognitive reserve'. This builds a buffer in the brain, making it more resilient. It means signs of decline only become evident at a higher threshold of illness or decay than when this buffer is absent."

The research team analysed data from 2,315 mentally fit participants aged over 65 years who took part in the first wave of interviews for the Cognitive Function and Ageing Study Wales (CFAS-Wales).

They analysed whether a healthy lifestyle was associated with better performance on a mental ability test. They found that a healthy diet, more physical activity, more social and mentally stimulating activity and moderate alcohol consumption all seemed to boost cognitive performance.

Professor Bob Woods of Bangor University, who leads the CFAS Wales study, said: "We found that people with a healthier lifestyle had better scores on tests of mental ability, and this was partly accounted for by their level of cognitive reserve.

"Our results highlight the important of policies and measures that encourage older people to make changes in their diet, exercise more, and engage in more socially oriented and mentally stimulating activities."

Professor Fiona Matthews of Newcastle University, who is principal statistician on the CFAS studies, said "Many of the factors found here to be important are not only healthy for our brain, but also help at younger age avoiding heart disease."

Professor Clare is supported by the National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care South West Peninsula (NIHR PenCLAHRC).

Testing our the efficacy of brain stimulation is part one aspect of the PROTECT (Platform for Research Online to investigate Genetics and Cognition in Ageing) trial, which involves Professor Clare. It has already recruited 20,000 people over the age of 50. They are taking part in Exeter-led research to establish which lifestyle measures can make a meaningful difference to keep people stay physically and mentally active in older age.

Science Daily/SOURCE : https://www.sciencedaily.com/releases/2017/04/170420113809.htm

Aerobic, resistance exercise combo can boost brain power of over 50s

Effects independent of current state of brain health, finds evidence review

April 24, 2017

Science Daily/BMJ
A combination of aerobic and resistance exercises can significantly boost the brain power of the over 50s, finds the most comprehensive review of the available evidence to date.

And the effects were evident irrespective of the current state of an individual's brain health, the analysis shows.

Physical exercise for older adults is seen as a promising means of warding off or halting a decline in brain health and cognitive abilities. Yet the evidence for its benefits is inconclusive, largely because of overly restrictive inclusion criteria in the reviews published to date, say the researchers.

In a bid to try and plug some of these gaps, they systematically reviewed 39 relevant studies published up to the end of 2016 to assess the potential impact of varying types, intensities, and durations of exercise on the brain health of the over 50s.

They included aerobic exercise; resistance training (such as weights); multi-component exercise, which contains elements of both aerobic and resistance training; tai chi; and yoga in their analysis.

They analysed the potential impact of these activities on overall brain capacity (global cognition); attention (sustained alertness, including the ability to process information rapidly); executive function (processes responsible for goal oriented behaviours); memory (storage and retrieval); and working memory (short term application of found information).

Pooled analysis of the data showed that exercise improves the brain power of the over 50s, irrespective of the current state of their brain health.

Aerobic exercise significantly enhanced cognitive abilities while resistance training had a pronounced effect on executive function, memory, and working memory.

The evidence is strong enough to recommend prescribing both types of exercise to improve brain health in the over 50s, say the researchers.

The data showed that tai chi also improved cognitive abilities, which backs the findings of previously published studies, but the analysis was based on just a few studies, caution the researchers, so will need to be confirmed in a large clinical trial.

Nevertheless, it's an important finding, they suggest, because exercises like tai chi may be suitable for people who are unable to do more challenging forms of physical activity.

And in terms of how much and how often, the data analysis showed that a session lasting between 45 and 60 minutes, of moderate to vigorous intensity, and of any frequency, was good for brain health.

The researchers point to some potential limitations of their review: their evidence was confined only to studies of supervised exercise and which had been published in English.

Nevertheless, they conclude: "The findings suggest that an exercise programme with components of both aerobic and resistance type training, of at least moderate intensity and at least 45 minutes per session, on as many days of the week as possible, is beneficial to cognitive function in adults aged over 50."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/04/170424215441.htm

Brain training can help in fight against dementia, meta-analysis shows

November 14, 2016

Science Daily/University of Sydney
Engaging in computer-based brain training can improve memory and mood in older adults with mild cognitive impairment, say researchers, but training is no longer effective once a dementia diagnosis has been made, they add.

The team, comprising researchers from the Brain and Mind Centre, reviewed more than 20 years of research and showed that brain training could lead to improvements in global cognition, memory, learning and attention, as well as psychosocial functioning (mood and self-perceived quality of life) in people with mild cognitive impairment. Conversely, when data from 12 studies of brain training in people with dementia was combined, results were not positive.

The results are published today in the American Journal of Psychiatry.

Mild cognitive impairment involves a decline in memory and other thinking skills despite generally intact daily living skills, and is one of strongest risk factors for dementia. People with mild cognitive impairment are at one-in-10 risk of developing dementia within a year -- and the risk is markedly higher among those with depression.

Brain training is a treatment for enhancing memory and thinking skills by practising mentally challenging computer-based exercises -- which are designed to look and feel like video games.

Dr Amit Lampit from the School of Psychology, who led the study said the results showed brain training could play an important role in helping to prevent dementia.

"Our research shows that brain training can maintain or even improve cognitive skills among older people at very high risk of cognitive decline -- and it's an inexpensive and safe treatment," Dr Lampit said.

To arrive at their conclusions, the team combined outcomes from 17 randomised clinical trials including nearly 700 participants, using a mathematical approach called meta-analysis, widely recognised as the highest level of medical evidence.

The team has used meta-analysis before to show that brain training is useful in other populations, such as healthy older adults and those with Parkinson's disease.

"Taken together, these wide-ranging analyses have provided the necessary evidence to pursue clinical implementation of brain training in the aged-care sector -- while continuing research aimed at improving training effectiveness," Dr Lampit said.

Associate Professor Michael Valenzuela, leader of the Regenerative Neuroscience Group at the Brain and Mind Centre, believes new technology is the key to moving the field forward.

"The great challenges in this area are maintaining training gains over the long term and moving this treatment out of the clinic and into people's homes. " Associate Professor Valenzuela said.

"This is exactly what we are working on right now."

Associate Professor Valenzuela is one of the leaders of the multi-million-dollar Australian Maintain your Brain trial that will test if a tailored program of lifestyle modification, including weekly brain training over four years, can prevent dementia in a group of 18,000 older adults.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/11/161114105531.htm

Unique visual stimulation may be new treatment for Alzheimer's

Noninvasive technique reduces beta amyloid plaques in mouse models of Alzheimer's disease

December 7, 2016

Science Daily/Massachusetts Institute of Technology
Using LED lights flickering at a specific frequency, researchers have shown that they can significantly reduce the beta amyloid plaques seen in Alzheimer's disease in the visual cortex of mice. This treatment appears to work by stimulating brain waves known as gamma oscillations, which the researchers discovered help the brain suppress beta amyloid production and invigorate cells responsible for destroying the plaques.
https://images.sciencedaily.com/2016/12/161207133541_1_540x360.jpg
Professor Li-Huei Tsai, director of MIT's Picower Institute for Learning and Memory, and senior author of the study, which appears in the Dec. 7 online edition of Nature.
Credit: Bryce Vickmark

This treatment appears to work by inducing brain waves known as gamma oscillations, which the researchers discovered help the brain suppress beta amyloid production and invigorate cells responsible for destroying the plaques.

Further research will be needed to determine if a similar approach could help Alzheimer's patients, says Li-Huei Tsai, the Picower Professor of Neuroscience, director of MIT's Picower Institute for Learning and Memory, and senior author of the study, which appears in the Dec. 7 online edition of Nature.

"It's a big 'if,' because so many things have been shown to work in mice, only to fail in humans," Tsai says. "But if humans behave similarly to mice in response to this treatment, I would say the potential is just enormous, because it's so noninvasive, and it's so accessible."

Tsai and Ed Boyden, an associate professor of biological engineering and brain and cognitive sciences at the MIT Media Lab and the McGovern Institute for Brain Research, who is also an author of the Nature paper, have started a company called Cognito Therapeutics to pursue tests in humans. The paper's lead authors are graduate student Hannah Iaccarino and Media Lab research affiliate Annabelle Singer.

"This important announcement may herald a breakthrough in the understanding and treatment of Alzheimer's disease, a terrible affliction affecting millions of people and their families around the world," says Michael Sipser, dean of MIT's School of Science. "Our MIT scientists have opened the door to an entirely new direction of research on this brain disorder and the mechanisms that may cause or prevent it. I find it extremely exciting."

Brain wave stimulation

Alzheimer's disease, which affects more than 5 million people in the United States, is characterized by beta amyloid plaques that are suspected to be harmful to brain cells and to interfere with normal brain function. Previous studies have hinted that Alzheimer's patients also have impaired gamma oscillations. These brain waves, which range from 25 to 80 hertz (cycles per second), are believed to contribute to normal brain functions such as attention, perception, and memory.

In a study of mice that were genetically programmed to develop Alzheimer's but did not yet show any plaque accumulation or behavioral symptoms, Tsai and her colleagues found impaired gamma oscillations during patterns of activity that are essential for learning and memory while running a maze.

Next, the researchers stimulated gamma oscillations at 40 hertz in a brain region called the hippocampus, which is critical in memory formation and retrieval. These initial studies relied on a technique known as optogenetics, co-pioneered by Boyden, which allows scientists to control the activity of genetically modified neurons by shining light on them. Using this approach, the researchers stimulated certain brain cells known as interneurons, which then synchronize the gamma activity of excitatory neurons.

After an hour of stimulation at 40 hertz, the researchers found a 40 to 50 percent reduction in the levels of beta amyloid proteins in the hippocampus. Stimulation at other frequencies, ranging from 20 to 80 hertz, did not produce this decline.

Tsai and colleagues then began to wonder if less-invasive techniques might achieve the same effect. Tsai and Emery Brown, the Edward Hood Taplin Professor of Medical Engineering and Computational Neuroscience, a member of the Picower Institute, and an author of the paper, came up with the idea of using an external stimulus -- in this case, light -- to drive gamma oscillations in the brain. The researchers built a simple device consisting of a strip of LEDs that can be programmed to flicker at different frequencies.

Using this device, the researchers found that an hour of exposure to light flickering at 40 hertz enhanced gamma oscillations and reduced beta amyloid levels by half in the visual cortex of mice in the very early stages of Alzheimer's. However, the proteins returned to their original levels within 24 hours.

The researchers then investigated whether a longer course of treatment could reduce amyloid plaques in mice with more advanced accumulation of amyloid plaques. After treating the mice for an hour a day for seven days, both plaques and free-floating amyloid were markedly reduced. The researchers are now trying to determine how long these effects last.

Furthermore, the researchers found that gamma rhythms also reduced another hallmark of Alzheimer's disease: the abnormally modified Tau protein, which can form tangles in the brain.

Tsai's lab is now studying whether light can drive gamma oscillations in brain regions beyond the visual cortex, and preliminary data suggest that this is possible. They are also investigating whether the reduction in amyloid plaques has any effects on the behavioral symptoms of their Alzheimer's mouse models, and whether this technique could affect other neurological disorders that involve impaired gamma oscillations.

Two modes of action

The researchers also performed studies to try to figure out how gamma oscillations exert their effects. They found that after gamma stimulation, the process for beta amyloid generation is less active. Gamma oscillations also improved the brain's ability to clear out beta amyloid proteins, which is normally the job of immune cells known as microglia.

"They take up toxic materials and cell debris, clean up the environment, and keep neurons healthy," Tsai says.

In Alzheimer's patients, microglia cells become very inflammatory and secrete toxic chemicals that make other brain cells more sick. However, when gamma oscillations were boosted in mice, their microglia underwent morphological changes and became more active in clearing away the beta amyloid proteins.

"The bottom line is, enhancing gamma oscillations in the brain can do at least two things to reduced amyloid load. One is to reduce beta amyloid production from neurons. And second is to enhance the clearance of amyloids by microglia," Tsai says.

The researchers also sequenced messenger RNA from the brains of the treated mice and found that hundreds of genes were over- or underexpressed, and they are now investigating the possible impact of those variations on Alzheimer's disease.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2016/12/161207133541.htm

Taking hour-long afternoon naps improves thinking and memory in older Chinese adults

January 5, 2017

Science Daily/American Geriatrics Society
Study participants who took an hour-long nap after lunch did better on the mental tests compared to the people who did not nap. Those who napped for about an hour also did better than people who took shorter or longer rests. People who took no naps, short naps, or longer naps experienced decreases in their mental ability that were about four to six times greater than people who took hour-long naps.

Preserving your memory, as well as your ability to think clearly and make decisions, is a key goal for people as they age. Researchers have a growing interest in the role sleep plays in helping older adults maintain their healthy mental function.

Recently, researchers examined information provided by nearly 3,000 Chinese adults aged 65 and older to learn whether taking an afternoon nap had any effect on mental health. Their study was published in the Journal of the American Geriatrics Society.

Nearly 60 percent of the people in the study said they napped after lunch in the afternoon. They napped between about 30 minutes to more than 90 minutes, with most people taking naps lasting about 63 minutes.

The participants took several tests to assess their mental status. They answered simple questions -- such as questions about the date, the season of the year, etc. -- and they did some basic math problems. Participants also were asked to memorize and recall words, and were asked to copy drawings of simple geometric figures. Finally, these older Chinese adults were asked questions about their napping and nighttime sleep habits.

According to the study's results, people who took an hour-long nap after lunch did better on the mental tests compared to the people who did not nap. Those who napped for about an hour also did better than people who took shorter or longer rests. People who took no naps, short naps, or longer naps experienced decreases in their mental ability that were about four-to-six times greater than people who took hour-long naps.

The people who did not nap, and those who took shorter or longer naps, experienced about the same decline in their mental abilities that a five-year increase in age would be expected to cause.

This summary is from "Afternoon Napping and Cognition in Chinese Older Adults: Findings From the China Health and Retirement Longitudinal Study (CHARLS) Baseline Assessment." It appears online ahead of print in the January 2017 issue of the Journal of the American Geriatrics Society. The study authors are Junxin Li, PhD; Pamela Z. Cacchione, PhD; Nancy Hodgson, PhD; Barbara Riegel, PhD; Brendan T. Keenan, MS; Mathew T. Scharf, MD, PhD; Kathy C. Richards, PhD; and Nalaka S. Gooneratne, MD.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/01/170105123148.htm

Meditation and music may help reverse early memory loss in adults at risk for Alzheimer’s Disease

January 21, 2017

Science Daily/IOS Press
In a recent study of adults with early memory loss, scientists found that practice of a simple meditation or music listening program may have multiple benefits for older adults with preclinical memory loss.

In this randomized controlled trial, 60 older adults with subjective cognitive decline (SCD), a condition that may represent a preclinical stage of Alzheimer's disease, were assigned to either a beginner meditation (Kirtan Kriya) or music listening program and asked to practice 12 minutes/day for 12 weeks. As detailed in a paper recently published by the Journal of Alzheimer's Disease, both the meditation and music groups showed marked and significant improvements in subjective memory function and objective cognitive performance at 3 months. These included domains of cognitive functioning most likely to be affected in preclinical and early stages of dementia (e.g., attention, executive function, processing speed, and subjective memory function). The substantial gains observed in memory and cognition were maintained or further increased at 6 months (3 months post-intervention).

As explained in the research team's previous paper (J Alzheimer's Dis. 52 (4): 1277-1298), both intervention groups also showed improvements in sleep, mood, stress, well-being and quality of life, with gains that were that were particularly pronounced in the meditation group; again, all benefits were sustained or further enhanced at 3 months post-intervention.

The findings of this trial suggest that two simple mind-body practices, Kirtan Kriya meditation and music listening, may not only improve mood, sleep, and quality of life, but also boost cognition and help reverse perceived memory loss in older adults with SCD.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/01/170121190807.htm

Mental activities may protect against mild cognitive impairment

January 30, 2017

Science Daily/Mayo Clinic
Researchers have found that engaging in mentally stimulating activities, even late in life, may protect against new-onset mild cognitive impairment, which is the intermediate stage between normal cognitive aging and dementia. The study found that cognitively normal people 70 or older who engaged in computer use, craft activities, social activities and playing games had a decreased risk of developing mild cognitive impairment.

Mayo Clinic researchers have found that engaging in mentally stimulating activities, even late in life, may protect against new-onset mild cognitive impairment, which is the intermediate stage between normal cognitive aging and dementia. The study found that cognitively normal people 70 or older who engaged in computer use, craft activities, social activities and playing games had a decreased risk of developing mild cognitive impairment. The results are published in the Jan. 30 edition of JAMA Neurology.

Researchers followed 1,929 cognitively normal participants of the population-based Mayo Clinic Study of Aging in Olmsted County, Minn., for an average duration of four years. After adjusting for sex, age and educational level, researchers discovered that the risk of new-onset mild cognitive impairment decreased by 30 percent with computer use, 28 percent with craft activities, 23 percent with social activities, and 22 percent with playing games.

"Our team found that persons who performed these activities at least one to two times per week had less cognitive decline than those who engaged in the same activities only two to three times per month or less," says Yonas Geda, M.D., psychiatrist and behavioral neurologist at Mayo Clinic's Arizona campus and senior author of the study.

Researchers conducted a neurocognitive assessment at the time of enrollment in the study, with evaluations every 15 months. Following the assessment, an expert consensus panel at the Alzheimer Disease Research Center at Mayo Clinic made the classification of normal cognition or mild cognitive impairment for each study participant, based on published criteria.

"Our previous cross-sectional study had found an association between engagement in mentally stimulating activities in late life and decreased odds of mild cognitive impairment," says Dr. Geda. "However, those findings were considered preliminary until confirmed by a prospective cohort study that we are now reporting in JAMA Neurology."

The benefits of being cognitively engaged even were seen among apolipoprotein E (APOE) ?4 carriers. APOE ?4 is a genetic risk factor for mild cognitive impairment and Alzheimer's dementia. However, for APOE ?4 carriers, only computer use and social activities were associated with a decreased risk of mild cognitive impairment.

"Even for a person who is at genetic risk for cognitive decline, engaging in some activities was beneficial," says Janina Krell-Roesch, Ph.D., the first author of the study and a postdoctoral researcher in Dr. Geda's Translational Neuroscience and Aging Program (TAP). "So I think the signal is there even for APOE ?4 carriers."

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/01/170130133315.htm

Mind reader: A consumer EEG device serves up rich new troves of scientific data

January 31, 2017

Science Daily/McMaster University
A wireless brain-sensing headband made to help users focus their thoughts is also generating valuable data for neuroscience researchers, shedding light on what happens to our thinking processes as we age, for example, or how women and men process thoughts differently.

A consumer device designed to help users focus their thoughts is also generating valuable data for neuroscience research.

A team of McMaster and industry researchers is using data collected by a wireless brain-sensing headband called Muse to shed new light on what happens to our thinking processes as we age, for example, or how women and men process thoughts differently. Their work is published in the journal eNeuro.

The device, developed by Toronto's InteraXon, is fitted with four electrodes. It registers and transmits the strength and amplitude of brain waves that reveal, for example, whether thinking is scattered or focused.

Muse shows users real-time information about their brain signals on their tablets or smartphones, creating a real-time feedback loop that they use to train themselves to reach a state of mindfulness and focus.

Users also have the option to share their electroencephalographic (EEG) data for research purposes, on a secure, anonymous basis. The manufacturer makes the resulting database available to qualified researchers, providing scientists an unprecedented snapshot of what is happening in the minds of thousands of people.

Traditional EEG monitoring is cumbersome, laborious and time-consuming. It can take hours to test a single subject in a traditional EEG research lab.

"On a good day, you could run one session of one experiment on maybe three people in the lab. Using Muse, we had a chance to test 6,000 people in multiple sessions. That's a lifetime's work in a normal EEG lab," says co-author Allison Sekuler, a McMaster professor of Psychology, Neuroscience and Behaviour. "The ability to be able test this many people at once, I think, is the future of where science is going. We're merging big data and neuroscience."

"It's taking science outside of the lab and enabling us to look at the brain in the real world," says co-author Ali Hashemi, a McMaster PhD student who works with Sekuler. "The large numbers of participants gave us the power to learn things we couldn't have with traditional lab studies."

The research describes new vistas of information opening with the availability of data from more than 6,000 adults -- a number that has grown by more than 10 times since the research was conducted.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/01/170131133720.htm

Sleep deprivation handicaps the brain's ability to form new memories, mouse study shows

Chemical recalibration of brain cells during sleep is crucial for learning, and sleeping pills may sabotage it

February 2, 2017

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/02/170202141916.htm
Science Daily/Johns Hopkins Medicine
Studying mice, scientists have fortified evidence that a key purpose of sleep is to recalibrate the brain cells responsible for learning and memory so the animals can 'solidify' lessons learned and use them when they awaken -- in the case of nocturnal mice, the next evening.
https://images.sciencedaily.com/2017/02/170202141916_1_540x360.jpg
Sleep is crucial for learning.
Credit: © Konstantin Yuganov / Fotolia

The researchers, all of the Johns Hopkins University School of Medicine, also report they have discovered several important molecules that govern the recalibration process, as well as evidence that sleep deprivation, sleep disorders and sleeping pills can interfere with the process.

"Our findings solidly advance the idea that the mouse and presumably the human brain can only store so much information before it needs to recalibrate," says Graham Diering, Ph.D., the postdoctoral fellow who led the study. "Without sleep and the recalibration that goes on during sleep, memories are in danger of being lost."

A summary of their study appears online in the journal Science on Feb. 3.

Diering explains that current scientific understanding of learning suggests that information is "contained" in synapses, the connections among neurons through which they communicate.

On the "sending side" of a synapse, signaling molecules called neurotransmitters are released by a brain cell as it "fires"; on the "receiving side," those molecules are captured by receptor proteins, which pass the "message" along. If a cell receives enough input through its synapses, it fires off its own neurotransmitters.

More specifically, experiments in animals have shown that the synapses on the receiving neuron can be toggled by adding or removing receptor proteins, thereby strengthening or weakening them and allowing the receiving neuron to receive more or less input from nearby signaling neurons.

Scientists believe memories are encoded through these synaptic changes. But there's a hitch in this thinking, Diering says, because while mice and other mammals are awake, the synapses throughout its brain tend to be strengthened, not weakened, pushing the system toward its maximum load. When neurons are "maxed out" and constantly firing, they lose their capacity to convey information, stymying learning and memory.

One possible reason that neurons don't usually max out is a process that has been well-studied in lab-grown neurons but not in living animals, asleep or awake. Known as homeostatic scaling down, it is a process that uniformly weakens synapses in a neural network by a small percentage, leaving their relative strengths intact and allowing learning and memory formation to continue.

To find out if the process does occur in sleeping mammals, Diering focused on the areas of the mouse brain responsible for learning and memory: the hippocampus and the cortex. He purified proteins from receiving synapses in sleeping and awake mice, looking for the same changes seen in lab-grown cells during scaling down.

Results showed a 20 percent drop in receptor protein levels in sleeping mice, indicating an overall weakening of their synapses, compared to mice that were awake.

"That was the first evidence of homeostatic scaling down in live animals," says Richard Huganir, Ph.D., professor of neuroscience, director of the Department of Neuroscience and lead author of the study. "It suggests that synapses are restructured throughout the mouse brain every 12 hours or so, which is quite remarkable."

To learn specifically which molecules were responsible for the phenomenon, the team turned to a protein called Homer1a, discovered in 1997 by Paul Worley, M.D., professor of neuroscience, who was also part of the team conducting the new study. Studies showed that Homer1a -- named for the ancient Greek author and the scientific "odyssey" required to identify it -- is important for the regulation of sleep and wakefulness, and for homeostatic scaling down in lab-grown neurons.

Repeating his previous analysis of synaptic proteins, Diering indeed found much higher levels of Homer1a -- 250 percent more -- in the synapses of sleeping mice than awake mice. And in genetically engineered mice missing Homer1a, the previous decrease of synaptic receptor proteins associated with sleep was no longer present.

To sort out how Homer1a senses when the mice are sleeping or awake, the researchers looked to the neurotransmitter noradrenaline, which drives the brain to arousal and wakefulness. By blocking or enhancing noradrenaline levels, both in lab-grown neurons and in mice, the researchers confirmed that when noradrenaline levels were high, Homer1a stayed away from synapses; when it was low, it collected there.

To directly test whether the location of Homer1a was related to sleep, the team kept mice awake for four extra hours by placing them in an unfamiliar cage. Some then got two and a half hours of "recovery sleep." As predicted, levels of Homer1a in the receiving synapses were much higher in the sleep-deprived mice than in those that got recovery sleep. That suggests, says Diering, that Homer1a is sensitive to an animal's "sleep need," not just what time of day it is.

Diering emphasizes that sleep need is controlled by adenosine, a chemical that accumulates in the brain as an animal stays awake, provoking sleepiness. (Caffeine, the world's most widely consumed psychoactive drug, directly interferes with adenosine.) When mice were given a drug during sleep deprivation that blocks adenosine, Homer1a levels no longer increased in their synapses.

"We think that Homer1a is a traffic cop of sorts," says Huganir. "It evaluates the levels of noradrenaline and adenosine to determine when the brain is sufficiently quiet to begin scaling down."

As the final test of their hypothesis that scaling down during sleep is crucial for learning and memory, the researchers tested the mice's ability to learn without scaling down. Individual mice were placed in an unfamiliar arena and given a mild electrical shock, either as they woke up or right before they went to sleep. Some mice then received a drug known to prevent scaling down.

When an undrugged mouse received a shock just before sleep, its brain went through the scaling-down process and formed an association between that arena and the shock. When placed in that same arena, those mice spent about 25 percent of their time motionless, in fear of another shock. When placed in a different unfamiliar arena, they froze sometimes, but only about 9 percent of their time there, probably because they were relatively good a telling the difference between the two unfamiliar arenas.

Expecting that drugged mice that couldn't scale down during sleep would have weaker memories and therefore freeze less than undrugged mice, Diering was surprised that they were motionless longer (40 percent of their time) when returned to the arena where they were shocked. But the drugged mice were also motionless longer (13 percent of their time) when in a new arena. When the shock was given after the mice woke up, the drug made no difference in how long the mice froze in either arena, confirming that scaling down only occurs during sleep.

"We think that the memory of the shock was stronger in the drugged mice because their synapses couldn't undergo scaling down, but all kinds of other memories also remained strong, so the mice were confused and couldn't easily distinguish the two arenas," says Diering. "This demonstrates why 'sleeping on it' can actually clarify your ideas."

"The bottom line," he says, "is that sleep is not really downtime for the brain. It has important work to do then, and we in the developed world are shortchanging ourselves by skimping on it."

Huganir says that sleep is still a big mystery. "In this study, we only examined what goes on in two areas of the brain during sleep. There are probably equally important processes happening in other areas, and throughout the body, for that matter," he adds.

Among the events that require further exploration is how learning and memory are affected by sleep disorders and other diseases known to disrupt sleep in humans, like Alzheimer's disease and autism. Huganir also says that benzodiazapines and other drugs that are commonly prescribed as sedatives, such as muscle relaxants and other sleep aids, are known to prevent homeostatic scaling down and are likely to interfere with learning and memory, though that idea has yet to be tested experimentally.

Science Daily/SOURCE :https://www.sciencedaily.com/releases/2017/02/170202141916.htm