What makes memories stronger?
Researchers shed new light on how the brain solidifies important memories
April 29, 2019
Science Daily/VIB (the Flanders Institute for Biotechnology)
A team of scientists at NeuroElectronics Research Flanders (NERF- empowered by imec, KU Leuven and VIB) found that highly demanding and rewarding experiences result in stronger memories. By studying navigation in rats, the researchers traced back the mechanism behind this selective memory enhancement to so-called replay processes in the hippocampus, the memory-processing center of the brain. These important findings provide new insights into one of the most enigmatic brain features: memory consolidation.
When we experience something important, we usually remember it better over time. This enhanced memory can be the result of stronger memory encoding during the experience, or because of memory consolidation that takes place after the experience. For example, experiences that turn out to be very rewarding have been found to lead to stronger and longer-lasting memories.
"One of the ways in which our brains consolidate memories is by mentally reliving the experience," explains Prof. Fabian Kloosterman, whose research is aimed at unravelling memory processing in the brain. "In biological terms, this boils down to the reactivation or replay of the neuronal activity patterns associated with a certain experience. This replay occurs in hippocampal-cortical brain networks during rest or sleep."
The question Kloosterman and his team at NERF set out to answer was whether the positive effect of rewards on hippocampal replay extend beyond the time of the experience itself and thus could further support enhanced memory consolidation.
Rewards and challenges
To find answers, the researchers trained rats to learn two goal locations in a familiar setting. One of the goals was a large reward -- nine food pellets -- while the other goal location only had a single food pellet on offer as a small reward. "Perhaps unsurprisingly, we found that rats remembered better the location where they found the large reward," says Frédéric Michon, PhD student in the Kloosterman lab, who conducted the experiments. "But we also observed that this reward-related effect on memory was strongest when the food pellets were located in places that required more complex memory formation."
Replay for better memory
To assess the contribution of replay brain activity after the actual experience, the researchers disrupted this particular signaling network, but only after the rats got a chance to discover the reward locations. Michon: "Mirroring our earlier findings, we observed that memory was impaired only for the highly rewarded locations, and in particular, when the rewards were at challenging locations."
In sum, the researchers could demonstrate that hippocampal replay, occurring after initial learning, contributes to the consolidation of highly rewarded experiences, and that this effect depends on the difficulty of a task. "A relatively simple experimental setting with rats and food pellets can teach us a lot about memory," says Kloosterman. "Our results demonstrate that replay contributes to the finely tuned selective consolidation of memories. Such insights could open future opportunities for treatments that help to strengthen memories, and could also help us understand memory decline in diseases such as dementia."
https://www.sciencedaily.com/releases/2019/04/190429111840.htm
Creativity is not just for the young
Two career paths revealed for Nobel laureates in economics
April 26, 2019
Science Daily/Ohio State University
If you believe that great scientists are most creative when they're young, you are missing part of the story.
A new study of winners of the Nobel Prize in economics finds that there are two different life cycles of creativity, one that hits some people early in their career and another that more often strikes later in life.
In this study, the early peak was found for laureates in their mid-20s and the later peak for those in their mid-50s.
The research supports previous work by the authors that found similar patterns in the arts and other sciences.
"We believe what we found in this study isn't limited to economics, but could apply to creativity more generally," said Bruce Weinberg, lead author of the study and professor of economics at The Ohio State University.
"Many people believe that creativity is exclusively associated with youth, but it really depends on what kind of creativity you're talking about."
Weinberg did the study with David Galenson, professor of economics at the University of Chicago. Their study appears in a special issue of the journal De Economist.
In the study, the Nobel Prize winners who did their most groundbreaking work early in their career tended to be "conceptual" innovators.
These type of innovators "think outside the box," challenging conventional wisdom and tend to come up with new ideas suddenly. Conceptual innovators tend to peak early in their careers, before they become immersed in the already accepted theories of the field, Weinberg said.
But there is another kind of creativity, he said, which is found among "experimental" innovators. These innovators accumulate knowledge through their careers and find groundbreaking ways to analyze, interpret and synthesize that information into new ways of understanding.
The long periods of trial and error required for important experimental innovations make them tend to occur late in a Nobel laureate's career.
"Whether you hit your creative peak early or late in your career depends on whether you have a conceptual or experimental approach," Weinberg said.
The researchers took a novel, empirical approach to the study, which involved 31 laureates. They arranged the laureates on a list from the most experimental to most conceptual.
This ranking was based on specific, objective characteristics of the laureates' single most important work that are indicative of a conceptual or experimental approach.
For example, conceptual economists tend to use assumptions, proofs and equations and have a mathematical appendix or introduction to their papers.
Experimental economists rely on direct inference from facts, so their papers tended to have more references to specific items, such as places, time periods and industries or commodities.
After classifying the laureates, the researchers determined the age at which each laureate made his most important contribution to economics and could be considered at his creative peak.
They did this through a convention of how academics rate the value and influence of a research paper. A paper is more influential in the field when other scientists mention -- or cite -- the paper in their own work. So the more citations a paper accumulates, the more influential it is.
Weinberg and Galenson used two different methods to calculate at which age the laureates were cited most often and thus were at the height of their creativity.
The two methods found that conceptual laureates peaked at about either 29 or 25 years of age. Experimental laureates peaked when they were roughly twice as old -- at about 57 in one method or the mid-50s in the other.
Most other research in this area has studied differences in peak ages of creativity between disciplines, such as physics versus medical sciences. These studies generally find small variations across disciplines, with creativity peaking in the mid-30s to early 40s in most scientific fields.
"These studies attribute differences in creative peaks to the nature of the scientific fields themselves, not to the scientists doing the work," Weinberg said.
"Our research suggests than when you're most creative is less a product of the scientific field that you're in and is more about how you approach the work you do."
The researchers were supported by grants from the National Science Foundation, the National Institute on Aging, the National Institutes of Health's Office of Behavioral and Social Sciences Research and the Ewing Marion Kauffman and Alfred P. Sloan foundations.
https://www.sciencedaily.com/releases/2019/04/190426075424.htm
Exercise activates memory neural networks in older adults
Study shows acute exercise has the ability to impact brain regions important to memory
April 25, 2019
Science Daily/University of Maryland
How quickly do we experience the benefits of exercise? A new University of Maryland study of healthy older adults shows that just one session of exercise increased activation in the brain circuits associated with memory -- including the hippocampus -- which shrinks with age and is the brain region attacked first in Alzheimer's disease.
"While it has been shown that regular exercise can increase the volume of the hippocampus, our study provides new information that acute exercise has the ability to impact this important brain region," said Dr. J. Carson Smith, an associate professor of kinesiology in the University of Maryland School of Public Health and the study's lead author.
The study is published in the Journal of the International Neuropsychological Society.
Dr. Smith's research team measured the brain activity (using fMRI) of healthy participants ages 55-85 who were asked to perform a memory task that involves identifying famous names and non famous ones. The action of remembering famous names activates a neural network related to semantic memory, which is known to deteriorate over time with memory loss.
This test was conducted 30 minutes after a session of moderately intense exercise (70% of max effort) on an exercise bike and on a separate day after a period of rest. Participants' brain activation while correctly remembering names was significantly greater in four brain cortical regions (including the middle frontal gyrus, inferior temporal gryus, middle temporal gyrus, and fusiform gyrus) after exercise compared to after rest. The increased activation of the hippocampus was also seen on both sides of the brain.
"Just like a muscle adapts to repeated use, single sessions of exercise may flex cognitive neural networks in ways that promote adaptations over time and lend to increased network integrity and function and allow more efficient access to memories," Dr. Smith explained.
https://www.sciencedaily.com/releases/2019/04/190425104310.htm
Train your brain, change your brain
April 14, 2019
Science Daily/D'Or Institute for Research and Education
Less than one hour of brain training with neurofeedback leads to a strengthening of neural connections and communication among brain areas. This is the main finding of a new study conducted at D'Or Institute for Research and Education (IDOR), published today in Neuroimage. According to the authors, the study may pave the way for the optimization and development of therapeutic approaches against stroke and Parkinson's, for example.
"We knew that the brain has an amazing ability to adapt itself, but we were not sure that we could observe these changes so quickly. Understanding of how we can impact on brain wiring and functioning is the key to treat neurological disorders," says Theo Marins, a biomedical scientist from IDOR and the Ph.D. responsible for the study.
Neurofeedback has been considered a promising way to regulate dysfunctional brain areas associated with disorders, such as chronic pain and depression, for example. With this technique, the magnetic resonance equipment helps individuals to have access to their own brain activity in real time and quickly gain control over it.
Thirty-six healthy subjects participated in the study in which the goal was to increase the activity of brain regions involved in hand movements. However, instead of actually move their hand, participants were asked to only imagine the movement, in total rest. Nineteen of them received the real brain training and the remaining seventeen were trained with placebo neurofeedback, for comparisons purposes. Immediately before and after the brain training, which lasted around 30 minutes, their neural networks were scanned in order to investigate the impact of the neurofeedback (or placebo) on brain wiring and communication, also known as structural and functional connectivity, respectively.
The results show that the corpus callosum -- the major cerebral bridge that connects the right and left hemispheres -- exhibited increased integrity, and the neural network controlling the movements of the body became strengthened. It seems that the whole system became more robust. Likewise, the training also had a positive impact on the default mode network, a brain network which is impaired after stroke, Parkinson's and depression, for example. These changes were not observed in the control group.
"We showed that the neurofeedback can be considered a powerful tool to induce brain changes at record speed. Now, our goal is to develop new studies to test whether patients with neurological disorders can also benefit from it," concludes Fernanda Tovar Moll, president of IDOR and leader of the study.
https://www.sciencedaily.com/releases/2019/04/190414111449.htm
Electrostimulation can improve working memory in people
As memories fade, can we supercharge them back to life?
April 12, 2019
Science Daily/Boston University
In a groundbreaking study published in Nature Neuroscience, Rob Reinhart, an assistant professor of psychological and brain sciences at Boston University and BU doctoral researcher John Nguyen, demonstrate that electrostimulation can improve the working memory of people in their 70s so that their performance on memory tasks is indistinguishable from that of 20-year-olds.
Reinhart and Nguyen's research targets working memory -- the part of the mind where consciousness lives, the part that is active whenever we make decisions, reason, and recall our grocery lists. Working memory starts to decline in our late 20s and early 30s, Reinhart explains, as certain areas of the brain gradually become disconnected and uncoordinated. By the time we reach our 60s and 70s, these neural circuits have deteriorated enough that many of us experience noticeable cognitive difficulties, even in the absence of dementias like Alzheimer's disease.
But the duo has discovered something incredible: by using electrical currents to noninvasively stimulate brain areas that have lost their rhythm, we can drastically improve working memory performance.
During the study, which was supported by a National Institutes of Health grant, they asked a group of people in their 20s and a group in their 60s and 70s to perform a series of memory tasks that required them to view an image, and then, after a brief pause, to identify whether a second image was slightly different from the original.
At baseline, the young adults were much more accurate at this, significantly outperforming the older group. However, when the older adults received 25 minutes of mild stimulation delivered through scalp electrodes and personalized to their individual brain circuits, the difference between the two groups vanished. Even more encouraging? That memory boost lasted at least to the end of the 50-minute time window after stimulation -- the point at which the experiment ended.
To understand why this technique is so effective, we need to take a look at the two mechanisms that allow working memory to function properly: coupling and synchronization.
Coupling occurs when different types of brain rhythms coordinate with one another, and it helps us process and store working memories. Slow, low-frequency rhythms -- theta rhythms -- dance in the front of your brain, acting like the conductors of an orchestra. They reach back to faster, high-frequency rhythms called gamma rhythms, which are generated in the region of the brain that processes the world around us.
Just as a musical orchestra contains flutes, oboes, violins -- so too, the gamma rhythms that reside within your brain each contribute something unique to the electricity-based orchestra that creates your memories. One gamma rhythm might process the color of an object you're holding in your mind, for instance, while another captures its shape, another its orientation, and another its sound.
But when the conductors fumble with their batons -- when the theta rhythms lose the ability to connect with those gamma rhythms to monitor them, maintain them, and instruct them -- the melodies within the brain begin to disintegrate and our memories lose their sharpness.
Meanwhile, synchronization -- when theta rhythms from different areas of the brain synchronize with one another -- allows separate brain areas to communicate with one another. This process serves as the glue for a memory, combining individual sensory details to create one coherent recollection. As we age, our theta rhythms become less synchronized and the fabric of our memories starts to fray.
Reinhart and Nguyen's work suggests that by using electrical stimulation, we can reestablish these pathways that tend to go awry as we age, improving our ability to recall our experiences by restoring the flow of information within the brain. And it's not just older adults that stand to benefit from this technique: it shows promise for younger people as well.
In the study, 14 of the young-adult participants performed poorly on the memory tasks despite their age -- so he called them back to stimulate their brains too.
"We showed that the poor performers who were much younger, in their 20s, could also benefit from the same exact kind of stimulation," Reinhart says. "We could boost their working memory even though they weren't in their 60s or 70s."
Coupling and synchronization, he adds, exist on a continuum: "It's not like there are people who don't couple versus people who couple."
On one end of the spectrum, someone with an incredible memory may be excellent at both synchronizing and coupling, whereas somebody with Alzheimer's disease would probably struggle significantly with both. Others lie between these two extremes -- for instance, you might be a weak coupler but a strong synchronizer, or vice versa.
And when we use this stimulation to alter neural symphonies, we aren't just making a minor tweak, Reinhart emphasizes. "It's behaviorally relevant. Now, [people are] performing tasks differently, they're remembering things better, they're perceiving better, they're learning faster. It is really extraordinary."
Looking ahead, he foresees a variety of future applications for his work.
"It's opening up a whole new avenue of potential research and treatment options," he says, "and we're super excited about it."
Reinhart would like to investigate electrostimulation's effects on individual brain cells by applying it to animal models, and he's curious about how repeated doses of stimulation might further enhance brain circuits in humans. Most of all, though, he hopes his discovery will one day lead to a treatment for the millions of people around the world living with cognitive impairments -- particularly those with Alzheimer's disease.
https://www.sciencedaily.com/releases/2019/04/190412130954.htm
Aging gracefully: Study identifies factors for healthy memory at any age
April 10, 2019
Science Daily/University of Alberta
University of Alberta neuroscientists have identified different factors for maintaining healthy memory and for avoiding memory decline in those over age 55, according to a new study. The results have implications for the prevention of Alzheimer's disease through targeted early intervention efforts.
Memory decline is one of the first signs of cognitive and neurodegenerative diseases, such as Alzheimer's disease. Understanding and designing interventions for memory decline is critical for efforts toward preventing or delaying these illnesses.
"We found different risk factors for stable memory and for rapidly declining memory," said Peggy McFall, lead author and research associate in the Department of Psychology. "It may be possible to use these factors to improve outcomes for older adults."
McFall, who conducted the study in collaboration with Professor Roger Dixon, used machine learning to analyze data from a longitudinal study based in Edmonton, Alberta.
The study found that adults with healthy memory were more likely to be female, educated, and engage in more social activities, such as hosting a dinner party, and novel cognitive activities, such as using a computer or learning a second language. For adults age 55 to 75, healthy memory was associated with lower heart rate, higher body mass index, more self-maintenance activities, and living companions. Adults over 75 had faster gait and fewer depressive symptoms.
Those with declining memory tended to engage in fewer new cognitive activities. Younger adults, age 55 to 75, younger, had higher heart rates, and engaged in fewer self-maintenance activities, while adults over age 75 had slower gait and engaged in fewer social activities.
"These modifiable risk and protective factors may be converted to potential intervention targets for the dual purpose of promoting healthy memory aging or preventing or delaying accelerated decline, impairment, and perhaps dementia," said McFall. For instance, clinicians might target specific groups with an intervention to increase new cognitive activities among men or improve mobility for those over age 75.
https://www.sciencedaily.com/releases/2019/04/190410090333.htm
Could eating garlic reduce aging-related memory problems?
April 8, 2019
Science Daily/Experimental Biology
Consuming garlic helps counteract age-related changes in gut bacteria associated with memory problems, according to a new study conducted with mice. The benefit comes from allyl sulfide, a compound in garlic known for its health benefits.
"Our findings suggest that dietary administration of garlic containing allyl sulfide could help maintain healthy gut microorganisms and improve cognitive health in the elderly," said Jyotirmaya Behera, PhD, who lead the research team with Neetu Tyagi, PhD, both from University of Louisville.
Behera will present the research at the American Physiological Society's annual meeting during the 2019 Experimental Biology meeting to be held April 6-9 in Orlando, Fla.
The gut contains trillions of microorganisms collectively referred to as the gut microbiota. Although many studies have shown the importance of these microorganisms in maintaining human health, less is known about health effects linked to gut microbiota changes that come with age.
"The diversity of the gut microbiota is diminished in elderly people, a life stage when neurodegenerative diseases such as Alzheimer's and Parkinson's develop and memory and cognitive abilities can decline," said Tyagi. "We want to better understand how changes in the gut microbiota relate to aging-associated cognitive decline."
For the study, the researchers gave oral allyl sulfide to mice that were 24 months old, which correlates to people between 56 and 69 years of age. They compared these mice with 4- and 24-month-old mice not receiving the dietary allyl sulfide supplement.
The researchers observed that the older mice receiving the garlic compound showed better long- and short-term memory and healthier gut bacteria than the older mice that didn't receive the treatment. Spatial memory was also impaired in the 24-month-old mice not receiving allyl sulfide.
Additional experiments revealed that reduced gene expression of neuronal-derived natriuretic factor (NDNF) in the brain was likely responsible for the cognitive decline. This gene was recently discovered by the University of Louisville researchers and is required for long-term and short-term memory consolidation.
The researchers found that mice receiving the garlic compound exhibited higher levels of NDNF gene expression. In addition, recombinant-NDNF protein therapy in the brain restored the cognitive abilities of the older mice that did not receive the garlic compound. The researchers also found that oral allyl sulfide administration produces hydrogen sulfide gas -- a messenger molecule that prevents intestinal inflammation -- in the gut lumen.
Overall, the new findings suggest that dietary allyl sulfide promotes memory consolidation by restoring gut bacteria. The researchers are continuing to conduct experiments aimed at better understanding the relationship between the gut microbiota and cognitive decline and are examining how garlic might be used as a treatment in the aging human population.
https://www.sciencedaily.com/releases/2019/04/190408091259.htm
Gum bacteria implicated in Alzheimer's and other diseases
Scientists trace path of bacterial toxins from the mouth to the brain and other tissues
April 7, 2019
Science Daily/Experimental Biology
Researchers are reporting new findings on how bacteria involved in gum disease can travel throughout the body, exuding toxins connected with Alzheimer's disease, rheumatoid arthritis and aspiration pneumonia. They detected evidence of the bacteria in brain samples from people with Alzheimer's and used mice to show that the bacterium can find its way from the mouth to the brain.
The bacterium, Porphyromonas gingivalis, is the bad actor involved in periodontitis, the most serious form of gum disease. These new findings underscore the importance of good dental hygiene as scientists seek ways to better control this common bacterial infection.
"Oral hygiene is very important throughout our life, not only for having a beautiful smile but also to decrease the risk of many serious diseases," said Jan Potempa, PhD, DSc, a professor at the University of Louisville School of Dentistry and head of the department of microbiology at Jagiellonian University in Krakow, Poland. "People with genetic risk factors that make them susceptible to rheumatoid arthritis or Alzheimer's disease should be extremely concerned with preventing gum disease."
While previous researchers have noted the presence of P. gingivalis in brain samples from Alzheimer's patients, Potempa's team, in collaboration with Cortexyme, Inc., offers the strongest evidence to date that the bacterium may actually contribute to the development of Alzheimer's disease. Potempa will present the research at the American Association of Anatomists annual meeting during the 2019 Experimental Biology meeting, held April 6-9 in Orlando, Fla.
The researchers compared brain samples from deceased people with and without Alzheimer's disease who were roughly the same age when they died. They found P. gingivalis was more common in samples from Alzheimer's patients, evidenced by the bacterium's DNA fingerprint and the presence of its key toxins, known as gingipains.
In studies using mice, they showed P. gingivalis can move from the mouth to the brain and that this migration can be blocked by chemicals that interact with gingipains. An experimental drug that blocks gingipains, known as COR388, is currently in phase 1 clinical trials for Alzheimer's disease. Cortexyme, Inc. and Potempa's team are working on other compounds that block enzymes important to P. gingivalis and other gum bacteria in hopes of interrupting their role in advancing Alzheimer's and other diseases.
The researchers also report evidence on the bacterium's role in the autoimmune disease rheumatoid arthritis, as well as aspiration pneumonia, a lung infection caused by inhaling food or saliva.
"P. gingivalis's main toxins, the enzymes the bacterium need to exert its devilish tasks, are good targets for potential new medical interventions to counteract a variety of diseases," said Potempa. "The beauty of such approaches in comparison to antibiotics is that such interventions are aimed only at key pathogens, leaving alone good, commensal bacteria, which we need."
P. gingivalis commonly begins to infiltrate the gums during the teenage years. About one in five people under age 30 have low levels of the bacterium in their gums. While it is not harmful in most people, if it grows to large numbers the bacteria provoke the body's immune system to create inflammation, leading to redness, swelling, bleeding and the erosion of gum tissue.
Making matters worse, P. gingivalis even causes benign bacteria in the mouth to change their activities and further increase the immune response. Bacteria can travel from the mouth into the bloodstream through the simple act of chewing or brushing teeth.
The best way to prevent P. gingivalis from growing out of control is by brushing and flossing regularly and visiting a dental hygienist at least once a year, Potempa said. Smokers and older people are at increased risk for infection. Genetic factors are also thought to play a role, but they are not well understood.
https://www.sciencedaily.com/releases/2019/04/190407144231.htm
Eyes reveal early Alzheimer's disease
Reduced blood capillaries are new way to diagnose early cognitive impairment
April 5, 2019
Science Daily/Northwestern Universit
Reduced blood capillaries in the back of the eye may be a new, noninvasive way to diagnose early cognitive impairment, the precursor to Alzheimer's disease in which individuals become forgetful, reports a newly published Northwestern Medicine study.
Scientists detected these vascular changes in the human eye non-invasively, with an infrared camera and without the need for dyes or expensive MRI scanners. The back of the eye is optically accessible to a new type of technology (OCT angiography) that can quantify capillary changes in great detail and with unparalleled resolution, making the eye an ideal mirror for what is going on in the brain.
"Once our results are validated, this approach could potentially provide an additional type of biomarker to identify individuals at high risk of progressing to Alzheimer's," said Dr. Amani Fawzi, a professor of ophthalmology at Northwestern University Feinberg School of Medicine and a Northwestern Medicine physician. "These individuals can then be followed more closely and could be prime candidates for new therapies aimed at slowing down the progression of the disease or preventing the onset of the dementia associated with Alzheimer's."
Therapies for Alzheimer's are more effective if they are started before extensive brain damage and cognitive decline have occurred, added Fawzi, the Cyrus Tang and Lee Jampol Professor of Ophthalmology.
The study was published April 2 in PLOS ONE.
It's known that patients with Alzheimer's have decreased retinal blood flow and vessel density but it had not been known if these changes are also present in individuals with early Alzheimer's or forgetful mild cognitive impairment who have a higher risk for progressing to dementia.
Multicenter trials could be implemented using this simple technology in Alzheimer's clinics. Larger datasets will be important to validate the marker as well as find the best algorithm and combination of tests that will detect high-risk subjects, said Sandra Weintraub, a co-author and professor of neurology and of psychiatry and behavioral sciences at Feinberg.
Weintraub and her team at the Northwestern Mesulam Center for Cognitive Neurology and Alzheimer's Disease recruited 32 participants who had cognitive testing consistent with the forgetful type of cognitive impairment, and age-, gender- and race- matched them to subjects who tested as cognitively normal for their age. All individuals underwent the eye imaging with OCT angiography. The data were analyzed to identify whether the vascular capillaries in the back of the eye were different between the two groups of individuals.
Now the team hopes to correlate these findings with other more standard (but also more invasive) types of Alzheimer's biomarkers as well as explore the longitudinal changes in the eye parameters in these subjects.
"Ideally the retinal findings would correlate well with other brain biomarkers," Fawzi said. "Long-term studies are also important to see if the retinal capillaries will change more dramatically in those who progressively decline and develop Alzheimer's dementia."
https://www.sciencedaily.com/releases/2019/04/190405124247.htm
Brain growth inhibited by heavy alcohol use
April 1, 2019
Science Daily/Oregon Health & Science University
New research in nonhuman primates shows that heavy use of alcohol can actually slow the rate of growth in developing brains. The study, to be published April 1, in the journal eNeuro, shows that heavy alcohol use reduced the rate of brain growth by 0.25 milliliters per year for every gram of alcohol consumed per kilogram of body weight. In human terms, that's the equivalent of four beers per day.
Heavy use of alcohol among adolescents and young adults is not only dangerous in its own right, but new research in nonhuman primates shows that it can actually slow the rate of growth in developing brains.
The study, published today in the journal eNeuro, shows that heavy alcohol use reduced the rate of brain growth by 0.25 milliliters per year for every gram of alcohol consumed per kilogram of body weight. In human terms, that's the equivalent of four beers per day. The research involved rhesus macaque monkeys at the Oregon National Primate Research Center.
"Chronic alcohol self-intoxication reduced the growth rate of brain, cerebral white matter and subcortical thalamus," the researchers write.
Researchers measured brain growth through magnetic resonance imaging of 71 rhesus macaques that voluntarily consumed ethanol or beverage alcohol. Scientists precisely measured intake, diet, daily schedules and health care, thus ruling out other factors that tend to confound results in observational studies involving people. The findings in the study help validate previous research examining the effect of alcohol use on brain development in people.
"Human studies are based on self-reporting of underage drinkers," said co-author Christopher Kroenke, Ph.D., an associate professor in the Division of Neuroscience at the primate center. "Our measures pinpoint alcohol drinking with the impaired brain growth."
The new study is the first to characterize normal brain growth of 1 milliliter per 1.87 years in rhesus macaques in late adolescence and early adulthood. And it further reveals a decrease in the volume of distinct brain areas due to voluntary consumption of ethanol.
Lead author Tatiana Shnitko, Ph.D., a research assistant professor in the Division of Neuroscience at the primate center, said previous research has shown the brain has a capacity to recover at least in part following the cessation of alcohol intake. However, it's not clear whether there would be long-term effects on mental functions as the adolescent and young adult brain ends its growth phase. The next stage of research will explore that question.
"This is the age range when the brain is being fine-tuned to fit adult responsibilities," Shnitko said. "The question is, does alcohol exposure during this age range alter the lifetime learning ability of individuals?"
https://www.sciencedaily.com/releases/2019/04/190401133019.htm
Trained musicians perform better -- at paying attention
Musical training improves the ability to tune out distractions, and the more training, the better the control, study finds
March 26, 2019
Science Daily/Elsevier
Musical training produces lasting improvements to a cognitive mechanism that helps individuals be more attentive and less likely to be distracted by irrelevant stimuli while performing demanding tasks. According to a new study appearing in the journal Heliyon, published by Elsevier, trained musicians demonstrate greater executive control of attention (a main component of the attentional system) than non-musicians. Notably, the more years of training musicians have, the more efficient they are at controlling their attention.
"Our study investigated the effects of systematic musical training on the main components of the attentional system. Our findings demonstrate greater inhibitory attentional control abilities in musicians than non-musicians. Professional musicians are able to more quickly and accurately respond to and focus on what is important to perform a task, and more effectively filter out incongruent and irrelevant stimuli than non-musicians. In addition, the advantages are enhanced with increased years of training," explained lead investigator, Paulo Barraza, PhD, Center for Advanced Research in Education, University of Chile, Santiago, Chile.
The attentional system consists of three subsystems that are mediated by anatomically distinct neural networks: alerting, orienting, and executive control networks. The alerting function is associated with maintaining states of readiness for action. The orienting function is linked to the selection of sensory information and change of attentional focus. The executive control function is involved both in the suppression of irrelevant, distracting stimuli and in top-down attentional control. The study's findings also demonstrated a correlation between the alerting and orienting networks in musicians than in non-musicians, possibly reflecting a functional relationship between these attentional networks derived from the deliberate practice of music.
The investigators recorded the behavioral responses of 18 professional pianists and a matched group of 18 non-musician professional adults who engaged in an attentional networks test. The musician group consisted of full-time conservatory students or conservatory graduates from Conservatories of the Universidad de Chile, Universidad Mayor de Chile, and Universidad Austral de Chile, with an average of more than 12 years of practice. "Non-musicians" were university students or graduates who had not had formal music lessons and could not play or read music.
The participants viewed and provided immediate feedback on rapidly presented image variations to test the efficiency of their reactive behavior. Mean scores of the alerting, orienting, and executive networks for the group of musicians were 43.84 milliseconds (ms), 43.70 ms, and 53.83 ms; for the group of non-musicians mean scores were 41.98 ms, 51.56 ms, and 87.19 ms, respectively. The higher scores show less efficient inhibitory attentional control.
Prior research has shown that systematic musical training results in changes to the brain that correlate with the enhancement of some specific musical abilities. However, musical training not only enhances the musical auditory perception, but also seems to have an impact on the processing of extra-musical cognitive abilities (e.g., working memory). According to the investigators, this is the first study to test the effect of musical training on attentional networks, which adds to previous research about the potential effect of musical practice on the development of extra-musical cognitive skills.
"Our findings of the relationship between musical training and improvement of attentional skills could be useful in clinical or educational fields, for instance, in strengthening the ability of ADHD individuals to manage distractions or the development of school programs encouraging the development of cognitive abilities through the deliberate practice of music. Future longitudinal research should directly address these interpretations," noted co-investigator David Medina, BMEd, Department of Music, Metropolitan University of Educational Sciences, Santiago, Chile.
https://www.sciencedaily.com/releases/2019/03/190326105604.htm
Diabetes treatment may keep dementia, Alzheimer's at bay
Study finds progression of dementia and Alzheimer's signature tangles are much faster in people with untreated diabetes
March 25, 2019
Science Daily/University of Southern California
A new study comparing people with diabetes, prediabetes and normal blood sugar finds that diabetes, left untreated, could mean a higher likelihood of developing dementia, including Alzheimer's disease.
Patients on medication for type 2 diabetes may be keeping Alzheimer's disease away.
USC Dornsife psychologists have found that those patients with untreated diabetes developed signs of Alzheimer's disease 1.6 times faster than people who did not have diabetes.
The study was published March 4 in the journal Diabetes Care.
"Our findings emphasize the importance of catching diabetes or other metabolic diseases in adults as early as you can," says Daniel A. Nation, a psychologist at USC Dornsife College of Letters, Arts and Sciences. "Among people with diabetes, the difference in their rate of developing the signs of dementia and Alzheimer's is clearly tied somehow to whether or not they are on medication for it."
Nation says that this study may be the first to compare the rate of developing the pathology for Alzheimer's disease and dementia among people with normal glucose levels, with pre-diabetes, or people with type 2 diabetes -- both treated and untreated.
For the study, the scientists were comparing the "tau pathology" -- the progression of the brain tangles that are the hallmark of Alzheimer's disease. When the tangles combine with sticky beta-amyloid plaques -- a toxic protein -- they disrupt signals between brain cells, impairing memory and other functions.
Nation and Elissa McIntosh, a USC Dornsife Ph.D. doctoral candidate in psychology, analyzed data collected by the Alzheimer's Disease Neuroimaging Initiative on 1,289 people age 55 and older. Data included biomarkers for diabetes and vascular disease, brain scans and a range of health indicators, including performance on memory tests.
For some participants, Nation and McIntosh were able to analyze 10 years' worth of data, while for others, they had one or four years.
Among 900 of those patients, 54 had type 2 diabetes but were not being treated, while 67 were receiving treatment.
Most people in the study -- 530 -- had normal blood sugar levels while 250 had prediabetes (hyperglycemia).
The researchers compared, among the different diabetic patient categories, the brain and spinal fluid test results that can indicate signs of amyloid plaques and the brain tangles.
"It is possible that the medicines for treating diabetes might make a difference in the progression of brain degeneration," Nation says. "But it's unclear how exactly those medications might slow or prevent the onset of Alzheimer's disease, so that is something we need to investigate."
Increasingly, scientists regard Alzheimer's disease as the result of a cascade of multiple problems, instead of triggered by one or two. The compounding factors range from pollution exposure and genetics (the ApoE4 gene, for instance) to heart disease and metabolic disease.
The study was supported by National Institutes of Health grants R21-AG-055034, P01-AG-052350 and P50-AG-005142 and Alzheimer's Association grant AA-008369.
The Alzheimer's Disease Neuroimaging Initiative is supported by the National Institute on Aging and the National Institute of Biomedical Imaging and Bioengineering, as well as other public and private partners.
https://www.sciencedaily.com/releases/2019/03/190325122011.htm
When it comes to hearing words, it's a division of labor between our brain's two hemispheres
March 4, 2019
Science Daily/New York University
Scientists have uncovered a new 'division of labor' between our brain's two hemispheres in how we comprehend the words and other sounds we hear -- a finding that offers new insights into the processing of speech and points to ways to address auditory disorders.
"Our findings point to a new way to think about the division of labor between the right and left hemispheres," says Adeen Flinker, the study's lead author and an assistant professor in the Department of Neurology at NYU School of Medicine. "While both hemispheres perform overlapping roles when we listen, the left hemisphere gauges how sounds change in time -- for example when speaking at slower or faster rates -- while the right is more attuned to changes in frequency, resulting in alterations in pitch."
Clinical observations dating back to the 19th century have shown that damage to the left, but not right, hemisphere impairs language processing. While researchers have offered an array of hypotheses on the roles of the left and right hemispheres in speech, language, and other aspects of cognition, the neural mechanisms underlying cerebral asymmetries remain debated.
In the study, which appears in the journal Nature Human Behavior, the researchers sought to elucidate the mechanisms underlying the processing of speech, with the larger aim of furthering our understanding of basic mechanisms of speech analysis as well as enriching the diagnostic and treatment tools for language disorders.
To do so, they created new tools to manipulate recorded speech, then used these recordings in a set of five experiments spanning behavioral experiments and two types of brain recording. They used magnetoencephalography (MEG), which allows measurements of the tiny magnetic fields generated by brain activity, as well as electrocorticography (ECoG), recordings directly from within the brain in volunteer surgical patients.
"We hope this approach will provide a framework to highlight the similarities and differences between human and non-human processing of communication signals," adds Flinker. "Furthermore, the techniques we provide to the scientific community may help develop new training procedures for individuals suffering from damage to one hemisphere."
The study's other authors were Werner Doyle, an associate professor in the Department of Neurosurgery at NYU School of Medicine, Ashesh Mehta, an associate professor of neurosurgery at the Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Orrin Devinsky, a professor in the Department of Neurology at NYU School of Medicine, and David Poeppel, a professor of psychology and neuroscience at NYU and director of the Max Planck Institute for Empirical Aesthetics in Frankfurt and the study's senior author.
https://www.sciencedaily.com/releases/2019/03/190304182116.htm
Study explores how technology can help prompt positive memories for people with depression
April 9, 2019
Science Daily/Lancaster University
A team of human-computer interaction researchers, have through in-depth interviews with experts in neuropsychology and cognitive behavioral therapies, found that most existing technologies related to supporting memory impairments are focused on 'episodic' impairments, which are closely associated with conditions such as dementia.
Researchers have provided a crucial first step towards understanding how computing technology could be used to help people with depression remember happy memories.
Improving the recall of positive memories is a method used by clinical experts treating memory impairments of people with depression. This is, among other things, to help offset a bias towards negative thinking.
However, there are currently few technologies that have been designed specifically to support people experiencing memory impairments associated with depression.
A team of human-computer interaction researchers from Lancaster University and Trinity College Dublin, have through in-depth interviews with experts in neuropsychology and cognitive behavioural therapies, found that most existing technologies related to supporting memory impairments are focused on 'episodic' impairments, which are closely associated with conditions such as dementia.
The researchers explored three memory impairments in depression: negative bias, over-generalisation, and reduced positivity.
"Memory impairments in depression are fundamentally different," said Corina Sas, Professor of Digital Health at Lancaster university and one of the researchers on the project. "Their effect is not felt through the loss of episodic memories, but rather difficulties in retrieving these memories among memories of general events and periods within their lifetime.
"People living with depression not only benefit less from the types of cues usually explored in existing memory technology research, but such cues can also be counterproductive."
The researchers identified several areas of opportunity for where technology could help.
These include:
· The use of 'biosensors', which could help inform technologies as to the current mind-set of the user.
· Technology that can actively prompt users with positive memories to counteract negative thoughts.
· Positive memory banks, which help people actively capture positive memories often by anticipating and planning for positive events.
· Technologies that enable the active curation of positive memories.
"Novel technologies that can adapt the retrieval of positive memories to the current emotional state of the user will be important," said Professor Sas.
"We can imagine technologies that prompt people to identify and retrieve positive memories as counterexamples for when people are ruminating over negative thoughts. This can help support a more balanced perspective on life, and help increase the accessibility and value of positive memories."
The study aims to inform specialists working in the 'Human-Computer Interaction' field about the limitations of existing memory technologies and factors to consider when designing new technologies to help people with depression. "These methods could be integrated into a range of different mental health technologies," said Gavin Doherty, Associate Professor at Trinity College Dublin, and co-founder of SilverCloud Health -- a health technology company.
The research, which is detailed in the paper 'Exploring and Designing for Memory Impairments in Depression', will be presented at the CHI2019 academic conference to be held in Glasgow in May. The work was supported by AffecTech: Personal Technologies for Affective Health, Marie Sklodowska-Curie Innovative Training Network funded by the European Commission H2020.
https://www.sciencedaily.com/releases/2019/04/190409100029.htm
More vitamin D may improve memory but too much may slow reaction time
Potential risks and benefits
March 14, 2019
Science Daily/Rutgers University
How much vitamin D can boost memory, learning and decision-making in older adults, and how much is too much? A unique study found that overweight and obese older women who took more than three times the recommended daily dose of vitamin D showed improvements in memory and learning -- but also had slower reaction times. The researchers hypothesize that slower reaction times may increase the risk of falling among older people.
A unique Rutgers-led study found that overweight and obese older women who took more than three times the recommended daily dose of vitamin D showed improvements in memory and learning -- but also had slower reaction times. The researchers hypothesize that slower reaction times may increase the risk of falling among older people.
The researchers, whose work is in the Journals of Gerontology: Series A, used computers to assess the impact of vitamin D on cognitive function. The researchers evaluated three groups of women between 50 and 70 years old in a randomized controlled trial.
One group took the recommended daily dose of 600 international units (IU), equivalent to 15 micrograms, of vitamin D each day for a year. Another group took 2,000 IU per day and the third took 4,000. All women participated in lifestyle counseling and were encouraged to lose a modest amount of weight.
The researchers found that memory and learning improved in the group that took 2,000 IU per day, but not in the group that took the higher dosage. Meanwhile, the women's reaction time showed a trend to be slower at 2,000 IU daily and was significantly slower at the higher dosage.
"The slower reaction time may have other negative outcomes such as potentially increasing the risk of falling and fractures," said senior author Sue Shapses, a professor in the Department of Nutritional Sciences at Rutgers University-New Brunswick and director of the New Jersey Obesity Group. "This is possible since other researchers have found that vitamin D supplementation at about 2,000 IU daily or more increased risk of falls, but they did not understand the cause. Our team's findings indicating a slower reaction time may be one answer. Many people think that more vitamin D supplementation is better, but this study shows that is not always the case."
Shapses said 4,000 IU a day might not be a problem for younger people but for the elderly it could compromise walking or catching one's balance to avoid a fall because their reaction time is slower. This is a presumption until future research can cover vitamin D levels, cognition and falls in one study, she added.
Vitamin D -- known for its importance for bone health -- is obtained through sun exposure and some foods. Researchers have also found that vitamin D has a major impact on how the body, including the brain, functions.
Cognitive impairment and dementia are significant public health problems, especially with aging, the study notes. Evidence shows that vitamin D plays a role in cognition and the normal functioning of the central nervous system.
More than one in four adults 65 and older fall each year, according to the U.S. Centers for Disease Control and Prevention. The annual U.S. toll includes 29 million falls, 3 million emergency department visits, 800,000 hospitalizations and 28,000 deaths. Falling also leads to more than $31 billion in annual Medicare costs, and the costs will surge unless the problem is recognized and prevention is stressed.
More research is needed to determine whether reaction time is related to rates of falls and injuries in at-risk populations. Examining different doses of vitamin D supplementation and from dietary sources in both men and women of different ages, and people of different races over a longer period, also needs to be studied, Shapses said. Larger studies are needed as well.
Brain wave stimulation may improve Alzheimer's symptoms
Noninvasive treatment improves memory and reduces amyloid plaques in mice
March 14, 2019
Science Daily/Massachusetts Institute of Technology
By exposing mice to a unique combination of light and sound, neuroscientists have shown they can improve cognitive and memory impairments similar to those seen in Alzheimer's patients.
This noninvasive treatment, which works by inducing brain waves known as gamma oscillations, also greatly reduced the number of amyloid plaques found in the brains of these mice. Plaques were cleared in large swaths of the brain, including areas critical for cognitive functions such as learning and memory.
"When we combine visual and auditory stimulation for a week, we see the engagement of the prefrontal cortex and a very dramatic reduction of amyloid," says Li-Huei Tsai, director of MIT's Picower Institute for Learning and Memory and the senior author of the study.
Further study will be needed, she says, to determine if this type of treatment will work in human patients. The researchers have already performed some preliminary safety tests of this type of stimulation in healthy human subjects.
MIT graduate student Anthony Martorell and Georgia Tech graduate student Abigail Paulson are the lead authors of the study, which appears in the March 14 issue of Cell.
Memory improvement
The brain's neurons generate electrical signals that synchronize to form brain waves in several different frequency ranges. Previous studies have suggested that Alzheimer's patients have impairments of their gamma-frequency oscillations, which range from 25 to 80 hertz (cycles per second) and are believed to contribute to brain functions such as attention, perception, and memory.
In 2016, Tsai and her colleagues first reported the beneficial effects of restoring gamma oscillations in the brains of mice that are genetically predisposed to develop Alzheimer's symptoms. In that study, the researchers used light flickering at 40 hertz, delivered for one hour a day. They found that this treatment reduced levels of beta amyloid plaques and another Alzheimer's-related pathogenic marker, phosphorylated tau protein. The treatment also stimulated the activity of debris-clearing immune cells known as microglia.
In that study, the improvements generated by flickering light were limited to the visual cortex. In their new study, the researchers set out to explore whether they could reach other brain regions, such as those needed for learning and memory, using sound stimuli. They found that exposure to one hour of 40-hertz tones per day, for seven days, dramatically reduced the amount of beta amyloid in the auditory cortex (which processes sound) as well as the hippocampus, a key memory site that is located near the auditory cortex.
"What we have demonstrated here is that we can use a totally different sensory modality to induce gamma oscillations in the brain. And secondly, this auditory-stimulation-induced gamma can reduce amyloid and Tau pathology in not just the sensory cortex but also in the hippocampus," says Tsai, who is a founding member of MIT's Aging Brain Initiative.
The researchers also tested the effect of auditory stimulation on the mice's cognitive abilities. They found that after one week of treatment, the mice performed much better when navigating a maze requiring them to remember key landmarks. They were also better able to recognize objects they had previously encountered.
They also found that auditory treatment induced changes in not only microglia, but also the blood vessels, possibly facilitating the clearance of amyloid.
Dramatic effect
The researchers then decided to try combining the visual and auditory stimulation, and to their surprise, they found that this dual treatment had an even greater effect than either one alone. Amyloid plaques were reduced throughout a much greater portion of the brain, including the prefrontal cortex, where higher cognitive functions take place. The microglia response was also much stronger.
"These microglia just pile on top of one another around the plaques," Tsai says. "It's very dramatic."
The researchers found that if they treated the mice for one week, then waited another week to perform the tests, many of the positive effects had faded, suggesting that the treatment would need to be given continually to maintain the benefits.
In an ongoing study, the researchers are now analyzing how gamma oscillations affect specific brain cell types, in hopes of discovering the molecular mechanisms behind the phenomena they have observed. Tsai says she also hopes to explore why the specific frequency they use, 40 hertz, has such a profound impact.
The combined visual and auditory treatment has already been tested in healthy volunteers, to assess its safety, and the researchers are now beginning to enroll patients with early-stage Alzheimer's to study its possible effects on the disease.
The research was funded, in part, by the Robert and Renee Belfer Family Foundation, the Halis Family Foundation, the JPB Foundation, the National Institutes of Health and the MIT Aging Brain Initiative.
https://www.sciencedaily.com/releases/2019/03/190314111004.htm
Researchers explore stroke's effects on microbiome
March 12, 2019
Science Daily/West Virginia University
Researchers are investigating how having a stroke can disrupt the community of bacteria that lives in the gut. These bacteria -- known collectively as the microbiome -- can interact with the central nervous system and may influence stroke patients' recovery.
Tumult in the bacterial community that occupies your gut -- known as your microbiome -- doesn't just cause indigestion. For people recovering from a stroke, it may influence how they get better.
A recent study by Allison Brichacek and Candice Brown, researchers in the West Virginia University School of Medicine, suggests that stroke patients' microbiomes -- and even the structure of their guts -- may still be out of kilter a month after the stroke has passed.
"We're interested in the gut-brain axis -- how the gut influences the brain and vice versa," said Brichacek, a doctoral student in the immunology and microbial pathogenesis graduate program. She presented her findings at the International Stroke Conference in February.
Previous studies indicated the immediate effects a stroke can have on someone's microbiome, but they didn't explore whether these effects lingered. To find out, Brichacek, Brown and their colleagues -- including Sophia Kenney, an undergraduate majoring in immunology and medical microbiology, and Stan Benkovic, a researcher in Brown's lab -- induced a stroke in animal models. Other models -- the control group -- didn't have a stroke. The researchers compared the two groups' microbiomes three days, 14 days and 28 days post-stroke. They also scrutinized their intestines for microscopic disparities.
Bacterial friend or foe?
One of the researchers' discoveries was that a certain family of bacteria -- Bifidobacteriaceae -- was less prominent in post-stroke models than in healthy ones both 14 and 28 days out. If the name of the family sounds familiar, that's probably because Bifidobacterium -- a genus within the Bifidobacteriaceae family -- is a common ingredient in yogurt and probiotics. These bacteria are known for supporting digestive health and may be associated with better outcomes in stroke patients.
Thatmay sound like bad news for people who have had a stroke, but the loss of Bifidobacteriaceae bacteria isn't the only long-term change their microbiomes undergo. Another family associated with worse outcomes -- Helicobacteraceae -- was also more common in post-stroke models 28 days out. The practical implications of these microbiotic shifts are still unknown.
The team also found that the ratio of one type of bacteria -- Firmicutes -- to another -- Bacteriodetes -- was higher in post-stroke models. After 14 days, the ratio in the experimental group was almost six times higher than in the control group. After 28 days, the experimental group's ratio had fallen, but it was still more than triple that of the control group. Having a high Firmicutes-to-Bacteriodetes ratio can be concerning because of its link to obesity, diabetes and inflammation.
Intestinal disorganization
The gut-brain axis seems to distribute a stroke's effects in another way, too. The research team discovered that a stroke can cause intestinal abnormalities. Under magnification, the intestinal tissues of healthy models resembled an orderly colony of coral. The branches of "coral" were actually villi -- tiny projections that increase the surface area of the intestinal wall and multiply the amount of nutrients it can absorb.
But in post-stroke models, the intestinal tissue looked scrambled, even a month after researchers triggered the stroke. "There's disorganization here," Brichacek said. "There's also less space between the villi to allow nutrients to move around." Poor circulation of nutrients can lead to compromised stroke recovery.
Treating the brain by treating the gut
What does all of this mean for stroke recovery? "Big picture: seeing a persistent, chronic change 28 days after stroke that is associated with this increase in some of the negative bacteria means that this could have negative effects on brain function and behavior. Ultimately, this could slow or prevent post-stroke recovery," said Brown, an assistant professor in Department of Neuroscience and faculty member in the Rockefeller Neuroscience Institute.
Her and Brichacek's findings may point to new therapeutic options for stroke. "If it ends up being that the gut has an influence on the repair of the brain, maybe our stroke treatments shouldn't just be focused on what we can do for the brain. Maybe we need to think about what can we do for the gut," Brichacek said.
For example, some bacteria in the gut produce short-chain fatty acids that affect brain function. "Some of these short-chain fatty acids are good, and some are bad," said Brown. "If the bacteria that produce some of the bad short-chain fatty acids are proliferating, that could have a negative outcome for brain function." Could nudging a stroke patient's microbiome in a healthier direction -- using probiotic supplements or prebiotic foods, for instance -- help prevent emotional or cognitive decline?
Likewise, might it be possible to lower a stroke patient's Firmicutes-to-Bacteriodetes ratio and promote weight loss, decrease diabetes risk and make subsequent strokes less likely?
The researchers' next step is to study intestinal changes in more depth. Just as the blood-brain barrier isolates the brain from the blood circulating elsewhere in the body, a barrier seals off the intestine from its surroundings. Brown and Brichacek want to know how a breach in the intestinal barrier could affect the central nervous system. Protecting this barrier is critical for the function of the enteric nervous system -- a part of the peripheral nervous system that includes the gut and often is called our "second brain" or "little brain."
"People don't appreciate the gut. It controls much more than digestion," Brown said. "Our results suggest that stroke targets both brains -- the brain in our head and the brain in our gut."
https://www.sciencedaily.com/releases/2019/03/190312123714.htm
Eating mushrooms may reduce the risk of cognitive decline
March 12, 2019
Science Daily/National University of Singapore
Researchers found that seniors who consume more than two standard portions of mushrooms weekly may have 50 percent reduced odds of having mild cognitive impairment.
A team from the Department of Psychological Medicine and Department of Biochemistry at the Yong Loo Lin School of Medicine at the National University of Singapore (NUS) has found that seniors who consume more than two standard portions of mushrooms weekly may have 50 per cent reduced odds of having mild cognitive impairment (MCI).
A portion was defined as three quarters of a cup of cooked mushrooms with an average weight of around 150 grams. Two portions would be equivalent to approximately half a plate. While the portion sizes act as a guideline, it was shown that even one small portion of mushrooms a week may still be beneficial to reduce chances of MCI.
"This correlation is surprising and encouraging. It seems that a commonly available single ingredient could have a dramatic effect on cognitive decline," said Assistant Professor Lei Feng, who is from the NUS Department of Psychological Medicine, and the lead author of this work.
The six-year study, which was conducted from 2011 to 2017, collected data from more than 600 Chinese seniors over the age of 60 living in Singapore. The research was carried out with support from the Life Sciences Institute and the Mind Science Centre at NUS, as well as the Singapore Ministry of Health's National Medical Research Council. The results were published online in the Journal of Alzheimer's Disease on 12 March 2019.
Determining MCI in seniors
MCI is typically viewed as the stage between the cognitive decline of normal ageing and the more serious decline of dementia. Seniors afflicted with MCI often display some form of memory loss or forgetfulness and may also show deficit on other cognitive function such as language, attention and visuospatial abilities. However, the changes can be subtle, as they do not experience disabling cognitive deficits that affect everyday life activities, which is characteristic of Alzheimer's and other forms of dementia.
"People with MCI are still able to carry out their normal daily activities. So, what we had to determine in this study is whether these seniors had poorer performance on standard neuropsychologist tests than other people of the same age and education background," explained Asst Prof Feng. "Neuropsychological tests are specifically designed tasks that can measure various aspects of a person's cognitive abilities. In fact, some of the tests we used in this study are adopted from commonly used IQ test battery, the Wechsler Adult Intelligence Scale (WAIS)."
As such, the researchers conducted extensive interviews and tests with the senior citizens to determine an accurate diagnosis. "The interview takes into account demographic information, medical history, psychological factors, and dietary habits. A nurse will measure blood pressure, weight, height, handgrip, and walking speed. They will also do a simple screen test on cognition, depression, anxiety," said Asst Prof Feng.
After this, a two-hour standard neuropsychological assessment was performed, along with a dementia rating. The overall results of these tests were discussed in depth with expert psychiatrists involved in the study to get a diagnostic consensus.
Mushrooms and cognitive impairment
Six commonly consumed mushrooms in Singapore were referenced in the study. They were golden, oyster, shiitake and white button mushrooms, as well as dried and canned mushrooms. However, it is likely that other mushrooms not referenced would also have beneficial effects.
The researchers believe the reason for the reduced prevalence of MCI in mushroom eaters may be down to a specific compound found in almost all varieties. "We're very interested in a compound called ergothioneine (ET)," said Dr Irwin Cheah, Senior Research Fellow at the NUS Department of Biochemistry. "ET is a unique antioxidant and anti-inflammatory which humans are unable to synthesise on their own. But it can be obtained from dietary sources, one of the main ones being mushrooms."
An earlier study by the team on elderly Singaporeans revealed that plasma levels of ET in participants with MCI were significantly lower than age-matched healthy individuals. The work, which was published in the journal Biochemical and Biophysical Research Communications in 2016, led to the belief that a deficiency in ET may be a risk factor for neurodegeneration, and increasing ET intake through mushroom consumption might possibly promote cognitive health.
Other compounds contained within mushrooms may also be advantageous for decreasing the risk of cognitive decline. Certain hericenones, erinacines, scabronines and dictyophorines may promote the synthesis of nerve growth factors. Bioactive compounds in mushrooms may also protect the brain from neurodegeneration by inhibiting production of beta amyloid and phosphorylated tau, and acetylcholinesterase.
Next steps
The potential next stage of research for the team is to perform a randomised controlled trial with the pure compound of ET and other plant-based ingredients, such as L-theanine and catechins from tea leaves, to determine the efficacy of such phytonutrients in delaying cognitive decline. Such interventional studies will lead to more robust conclusion on causal relationship. In addition, Asst Prof Feng and his team also hope to identify other dietary factors that could be associated with healthy brain ageing and reduced risk of age-related conditions in the future.
https://www.sciencedaily.com/releases/2019/03/190312103702.htm
Could an eye doctor diagnose Alzheimer's before you have symptoms?
Study suggests loss of blood vessels in retina reflect changes in brain health
March 11, 2019
Science Daily/Duke University Medical Center
A study of more than 200 people suggests the loss of blood vessels in the retina could signal Alzheimer's disease.
A study of more than 200 people at the Duke Eye Center publishing March 11 in the journal Ophthalmology Retina suggests the loss of blood vessels in the retina could signal Alzheimer's disease.
In people with healthy brains, microscopic blood vessels form a dense web at the back of the eye inside the retina, as seen in 133 participants in a control group.
In the eyes of 39 people with Alzheimer's disease, that web was less dense and even sparse in places. The differences in density were statistically significant after researchers controlled for factors including age, sex, and level of education, said Duke ophthalmologist and retinal surgeon Sharon Fekrat, M.D., the study's senior author.
"We're measuring blood vessels that can't be seen during a regular eye exam and we're doing that with relatively new noninvasive technology that takes high-resolution images of very small blood vessels within the retina in just a few minutes," she said. "It's possible that these changes in blood vessel density in the retina could mirror what's going on in the tiny blood vessels in the brain, perhaps before we are able to detect any changes in cognition."
The study found differences in the retinas of those with Alzheimer's disease when compared to healthy people and to those with mild cognitive impairment, often a precursor to Alzheimer's disease.
With nearly 6 million Americans living with Alzheimer's disease and no viable treatments or noninvasive tools for early diagnosis, its burden on families and the economy is heavy. Scientists at Duke Eye Center and beyond have studied other changes in the retina that could signal trouble upstream in the brain, such as thinning of some of the retinal nerve layers.
"We know that there are changes that occur in the brain in the small blood vessels in people with Alzheimer's disease, and because the retina is an extension of the brain, we wanted to investigate whether these changes could be detected in the retina using a new technology that is less invasive and easy to obtain," said Dilraj S. Grewal, M.D., a Duke ophthalmologist and retinal surgeon and a lead author on the study. The Duke study used a noninvasive technology called optical coherence tomography angiography (OCTA). OCTA machines use light waves that reveal blood flow in every layer of the retina.
An OCTA scan could even reveal changes in tiny capillaries -- most less than half the width of a human hair -- before blood vessel changes show up on a brain scan such as an MRI or cerebral angiogram, which highlight only larger blood vessels. Such techniques to study the brain are invasive and costly.
"Ultimately, the goal would be to use this technology to detect Alzheimer's early, before symptoms of memory loss are evident, and be able to monitor these changes over time in participants of clinical trials studying new Alzheimer's treatments," Fekrat said.
https://www.sciencedaily.com/releases/2019/03/190311090958.htm
Keeping active in middle age may be tied to lower risk of dementia
February 25, 2019
Science Daily/University of Gothenburg
Keeping physically and mentally active in middle age may be tied to a lower risk of developing dementia decades later, according to a new study. Mental activities included reading, playing instruments, singing in a choir, visiting concerts, gardening, doing needlework or attending religious services.
"These results indicate that these activities in middle age may play a role in preventing dementia in old age and preserving cognitive health," said study author Jenna Najar, MD, from Sahlgrenska Academy, University of Gothenburg.
"It's exciting as these are activities that people can incorporate into their lives pretty easily and without a lot of expense."
The study involved 800 Swedish women with an average age of 47 who were followed for 44 years. At the beginning of the study, participants were asked about their mental and physical activities.
Mental activities included intellectual activities, such as reading and writing; artistic activities, such as going to a concert or singing in a choir; manual activities, such as needlework or gardening; club activities; and religious activity.
Participants were given scores in each of the five areas based on how often they participated in mental activities, with a score of zero for no or low activity, one for moderate activity and two for high activity. For example, moderate artistic activity was defined as attending a concert, play or art exhibit during the last six months, while high artistic activity was defined as more frequent visits, playing an instrument, singing in a choir or painting. The total score possible was 10.
Participants were divided into two groups. The low group, with 44 percent of participants, had scores of zero to two and the high group, with 56 percent of participants, had scores of three to 10.
For physical activity, participants were divided into two groups, active and inactive. The active group ranged from light physical activity such as walking, gardening, bowling or biking for a minimum of four hours per week to regular intense exercise such as running or swimming several times a week or engaging in competitive sports. A total of 17 percent of the participants were in the inactive group and 82 percent were in the active group.
During the study, 194 women developed dementia. Of those, 102 had Alzheimer's disease, 27 had vascular dementia and 41 had mixed dementia, which is when more than one type of dementia is present, such as the plaques and tangles of Alzheimer's disease along with the blood vessel changes seen in vascular dementia.
The study found that women with a high level of mental activities were 46 percent less likely to develop Alzheimer's disease and 34 percent less likely to develop dementia overall than the women with the low level of mental activities. The women who were physically active were 52 percent less likely to develop dementia with cerebrovascular disease and 56 percent less likely to develop mixed dementia than the women who were inactive.
The researchers took into account other factors that could affect the risk of dementia, such as high blood pressure, smoking and diabetes. They also ran the results again after excluding women who developed dementia about halfway through the study to rule out the possibility that those women may have been in the prodromal stage of dementia, with less participation in the activities as an early symptom. The results were similar, except that physical activity was then associated with a 34-percent reduced risk of dementia overall.
Of the 438 women with the high level of mental activity, 104 developed dementia, compared to 90 of the 347 women with the low level of activity. Of the 648 women with the high level of physical activity, 159 developed dementia, compared to 35 of the 137 women who were inactive.
https://www.sciencedaily.com/releases/2019/02/190225145650.htm