Memory 10

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

Native California medicinal plant may hold promise for treating Alzheimer's

Salk scientists identify possible healing compound in Yerba santa

February 20, 2019

Science Daily/Salk Institute

The medicinal powers of aspirin, digitalis, and the anti-malarial artemisinin all come from plants. A discovery of a potent neuroprotective and anti-inflammatory chemical in a native California shrub may lead to a treatment for Alzheimer's disease based on a compound found in nature.

 

"Alzheimer's disease is a leading cause of death in the United States," says Senior Staff Scientist Pamela Maher, a member of Salk's Cellular Neurobiology Laboratory, run by Professor David Schubert. "And because age is a major risk factor, researchers are looking at ways to counter aging's effects on the brain. Our identification of sterubin as a potent neuroprotective component of a native California plant called Yerba santa (Eriodictyon californicum) is a promising step in that direction."

 

Native California tribes, which dubbed the plant "holy herb" in Spanish, have long used Yerba santa for its medicinal properties. Devotees brew its leaves to treat respiratory ailments, fever and headaches; and mash it into a poultice for wounds, sore muscles and rheumatism.

 

To identify natural compounds that might reverse neurological disease symptoms, Maher applied a screening technique used in drug discovery to a commercial library of 400 plant extracts with known pharmacological properties. The lab had previously used this approach to identify other chemicals (called flavonoids) from plants that have anti-inflammatory and neuroprotective properties.

 

Through the screen, the lab identified a molecule called sterubin as Yerba santa's most active component. The researchers tested sterubin and other plant extracts for their impact on energy depletion in mouse nerve cells, as well as other age-associated neurotoxicity and survival pathways directly related to the reduced energy metabolism, accumulation of misfolded, aggregated proteins and inflammation seen in Alzheimer's. Sterubin had a potent anti-inflammatory impact on brain cells known as microglia. It was also an effective iron remover -- potentially beneficial because iron can contribute to nerve cell damage in aging and neurodegenerative diseases. Overall, the compound was effective against multiple inducers of cell death in the nerve cells, according to Maher.

 

"This is a compound that was known but ignored," Maher says. "Not only did sterubin turn out to be much more active than the other flavonoids in Yerba santa in our assays, it appears as good as, if not better than, other flavonoids we have studied."

 

Next, the lab plans to test sterubin in an animal model of Alzheimer's, then determine its drug-like characteristics and toxicity levels in animals. With that data, Maher says, it might be possible to test the compound in humans, although it would be critical to use sterubin derived from plants grown under standardized, controlled conditions. She says the team will likely generate synthetic derivatives of sterubin.

https://www.sciencedaily.com/releases/2019/02/190220174105.htm

Chronic inflammation in middle age may lead to thinking and memory problems later

February 13, 2019

Science Daily/American Academy of Neurology

People who have chronic inflammation in middle-age may develop problems with thinking and memory in the decades leading up to old age.

 

There are two kinds of inflammation. Acute inflammation happens when the body's immune response jumps into action to fight off infection or an injury. It is localized, short-term and part of a healthy immune system. Chronic inflammation is not considered healthy. It is a low-grade inflammation that lingers for months or even years throughout the body. It can be caused by autoimmune disorders like rheumatoid arthritis or multiple sclerosis, physical stress or other causes. Symptoms of chronic inflammation include joint pain or stiffness, digestive problems and fatigue.

 

Ways to reduce chronic inflammation include getting regular exercise, following an anti-inflammatory heart healthy diet, and getting enough sleep.

 

"Chronic inflammation is tough on the body, and can damage joints, internal organs, tissue and cells," said study author Keenan A. Walker, PhD, of Johns Hopkins University in Baltimore, Md. "It can also lead to heart disease, stroke and cancer. While other studies have looked at chronic inflammation and its effects on the brain in older people, our large study investigated chronic inflammation beginning in middle age and showed that it may contribute to cognitive decline in the decades leading up to old age."

 

As part of the Atherosclerosis Risk in Communities (ARIC) Study, researchers followed 12,336 people with an average age of 57 for approximately 20 years. Researchers took blood samples from participants at the start of the study, measuring four biomarkers of inflammation: fibrinogen, white blood cell count, von Willebrand factor, and factor VIII. They created a composite inflammation score for the four biomarkers. Three years later, researchers measured C-reactive protein, another blood biomarker of inflammation. Participants were divided into four groups based on their composite inflammation scores and C-reactive protein levels.

 

Participants' thinking and memory skills were tested at the beginning of the study, six to nine years later, and at the end of the study.

 

Researchers found the group with the highest levels of inflammation biomarkers had an 8-percent steeper decline in thinking and memory skills over the course of the study than the group with the lowest levels of inflammation biomarkers. The group with the highest C-reactive protein levels had a 12-percent steeper decline in thinking and memory skills than the group with the lowest levels. These results were derived after researchers adjusted for other factors that could affect thinking and memory skills, such as education, heart disease and high blood pressure. Further analyses revealed that inflammation-associated declines in thinking were most prominent in areas of memory, compared to other aspects of thinking such as language and executive functioning.

 

"Overall, the additional change in thinking and memory skills associated with chronic inflammation was modest, but it was greater than what has been seen previously associated with high blood pressure in middle age," Walker said.

 

"Many of the processes that can lead to a decline in thinking and memory skills are believed to begin in middle age, and it is in middle age that they may also be most responsive to intervention," said Walker. "Our results show that chronic inflammation may be an important target for intervention. However, it's also possible that chronic inflammation is not a cause and instead a marker of, or even a response to, neurodegenerative brain diseases that can lead to cognitive decline."

 

A limitation of the study was that participants with higher levels of chronic inflammation at the start of the study were more likely to drop out or die before the final follow-up visit, so surviving participants may not be representative of the general population.

 

Future studies could include more frequent assessments of thinking and memory skills. They could also examine a larger variety of inflammation markers in the blood.

https://www.sciencedaily.com/releases/2019/02/190213160535.htm

With age comes hearing loss and a greater risk of cognitive decline

But study suggests higher education might counter effects of milder hearing impairment

February 12, 2019

Science Daily/University of California - San Diego

In a new study, researchers report that hearing impairment is associated with accelerated cognitive decline with age, though the impact of mild hearing loss may be lessened by higher education

 

Hearing impairment is a common consequence of advancing age. Almost three-quarters of U.S. adults age 70 and older suffer from some degree of hearing loss. One unanswered question has been to what degree hearing impairment intersects with and influences age-related cognitive decline.

 

In a new study, researchers at University of California San Diego School of Medicine report that hearing impairment is associated with accelerated cognitive decline with age, though the impact of mild hearing loss may be lessened by higher education.

 

The findings are published in the February 12, 2019 issue of the Journal of Gerontology: Series A Medical Sciences.

 

A team of scientists, led by senior author Linda K. McEvoy, PhD, professor in the departments of Radiology and Family Medicine and Public Health, tracked 1,164 participants (mean age 73.5 years, 64 percent women) in the longitudinal Rancho Bernardo Study of Healthy Aging for up to 24 years. All had undergone assessments for hearing acuity and cognitive function between the years 1992 to 1996 and had up to five subsequent cognitive assessments at approximately four-year intervals. None used a hearing aid.

 

The researchers found that almost half of the participants had mild hearing impairment, with 16.8 percent suffering moderate-to-severe hearing loss. Those with more serious hearing impairment showed worse performance at the initial visit on a pair of commonly used cognitive assessment tests: the Mini-Mental State Exam (MMSE) and the Trail-Making Test, Part B. Hearing impairment was associated with greater decline in performance on these tests over time, both for those with mild hearing impairment and those with more severe hearing impairment.

 

However, the association of mild hearing impairment with rate of cognitive decline was modified by education. Mild hearing impairment was associated with steeper decline among study participants without a college education, but not among those with higher education. Moderate-to-severe hearing impairment was associated with steeper MMSE decline regardless of education level.

 

"We surmise that higher education may provide sufficient cognitive reserve to counter the effects of mild hearing loss, but not enough to overcome effects of more severe hearing impairment," said McEvoy.

 

Degree of social engagement did not affect the association of hearing impairment with cognitive decline. "This was a somewhat unexpected finding" said first author Ali Alattar. "Others have postulated that cognitive deficits related to hearing impairment may arise from social isolation, but in our study, participants who had hearing impairment were as socially engaged as those without hearing loss."

 

The findings, said the authors, emphasize the need for physicians to be aware that older patients with hearing impairments are at greater risk for cognitive decline. They also emphasized the importance of preventing hearing loss at all ages, since hearing impairment is rarely reversible. One important way to protect hearing, they said, is to minimize loud noise exposure since this is the largest modifiable risk factor for hearing impairment.

https://www.sciencedaily.com/releases/2019/02/190212134802.htm

 

Exercise may improve thinking skills in people as young as 20

January 30, 2019

Science Daily/American Academy of Neurology

Regular aerobic exercise such as walking, cycling or climbing stairs may improve thinking skills not only in older people but in young people as well, according to a new study. The study also found that the positive effect of exercise on thinking skills may increase as people age.

 

The specific set of thinking skills that improved with exercise is called executive function. Executive function is a person's ability to regulate their own behavior, pay attention, organize and achieve goals.

 

"As people age, there can be a decline in thinking skills, however our study shows that getting regular exercise may help slow or even prevent such decline," said study author Yaakov Stern, PhD, of Columbia University in New York, and a member of the American Academy of Neurology. "We found that all participants who exercised not only showed improvements in executive function but also increased the thickness in an area of the outer layer of their brain."

 

The study involved 132 people between the ages of 20 and 67 who did not smoke or have dementia but who also did not exercise at the start of the study and were determined to have below average fitness levels. Participants were randomly assigned to six months of either aerobic exercise or stretching and toning four times a week. The two groups were equally balanced for age, sex, education as well as memory and thinking skills at the start of the study.

 

All participants either exercised or stretched and toned at a fitness center and checked in weekly with coaches monitoring their progress. They all wore heart rate monitors as well. Participants' thinking and memory skills were evaluated at the start of the study as well as at three months and at the end of the six-month study.

 

Participants in the exercise group chose from aerobic activities including walking on a treadmill, cycling on a stationary bike or using an elliptical machine. They ramped up their activity during the first month, then during the remainder of the six-month study they trained at 75 percent of their maximum heart rate. People in the stretching and toning group did exercises to promote flexibility and core strength.

 

Researchers measured participants' aerobic capacity using a cycling machine called an ergometer that estimates exercise intensity. Participants also had MRI brain scans at the start and end of the study.

 

Researchers found that aerobic exercise increased thinking skills. From the beginning of the study to the end, those who did aerobic exercise improved their overall scores on executive function tests by 0.50 points, which was a statistically significant difference from those who did stretching and toning, who improved by 0.25 points. At age 40, the improvement in thinking skills was 0.228 standard deviation units higher in those who exercised compared to those who did stretching and toning and at age 60, it was 0.596 standard deviation units higher.

 

"Since a difference of 0.5 standard deviations is equivalent to 20 years of age-related difference in performance on these tests, the people who exercised were testing as if they were about 10 years younger at age 40 and about 20 years younger at age 60," Stern said.

 

He added, "Since thinking skills at the start of the study were poorer for participants who were older, our findings suggest that aerobic exercise is more likely to improve age-related declines in thinking skills rather than improve performance in those without a decline."

 

Researchers also found an increase in the thickness of the outer layer of the brain in the left frontal area in all those who exercised, suggesting that aerobic exercise contributes to brain fitness at all ages.

 

"Our research confirms that exercise can be beneficial to adults of any age," said Stern.

 

Overall, researchers did not find a link between exercise and improved memory skills. However, those with the genetic marker for dementia, the APOE ?4 allele, showed less improvement in thinking skills.

 

A limitation of the study is the small number of participants. Larger studies over longer periods of time may allow researchers to see other effects in thinking and memory skills.

 

The study was supported by the National Institutes of Health.

https://www.sciencedaily.com/releases/2019/01/190130161638.htm

How exercise may protect against Alzheimer's

February 8, 2019

Science Daily/Columbia University Irving Medical Center

A hormone called irisin -- produced during exercise -- may protect neurons against Alzheimer's disease.

 

Athletes know a vigorous workout can release a flood of endorphins: "feel-good" hormones that boost mood. Now there's evidence that exercise produces another hormone that may improve memory and protect against Alzheimer's disease, according to a study co-led by Ottavio Arancio, MD, PhD, a researcher at Columbia University's Vagelos College of Physicians and Surgeons and Taub Institute for Research on Alzheimer's Disease and the Aging Brain.

 

The study was published in Nature Medicine.

 

Physical activity is known to improve memory, and studies suggest it may also reduce the risk of Alzheimer's disease. But researchers don't understand why.

 

A few years ago, exercise researchers discovered a hormone called irisin that is released into the circulation during physical activity. Initial studies suggested that irisin mainly played a role in energy metabolism. But newer research found that the hormone may also promote neuronal growth in the brain's hippocampus, a region critical for learning and memory.

 

"This raised the possibility that irisin may help explain why physical activity improves memory and seems to play a protective role in brain disorders such as Alzheimer's disease" says Arancio, who is a professor of pathology and cell biology and of medicine at Columbia University Vagelos College of Physicians and Surgeons.

 

Irisin is reduced in brains of people with Alzheimer's

 

In the new study, Arancio and his colleagues at the Federal University of Rio de Janeiro in Brazil and Queens University in Canada first looked for a link between irisin and Alzheimer's in people. Using tissue samples from brain banks, they found that irisin is present in the human hippocampus and that hippocampal levels of the hormone are reduced in individuals with Alzheimer's.

 

To explore what irisin does in the brain, the team turned to mice. These experiments show that irisin, in mice, protects the brain's synapses and the animals' memory: When irisin was disabled in the hippocampus of healthy mice, synapses and memory weakened. Similarly, boosting brain levels of irisin improved both measures of brain health.

 

Swimming boosts irisin, protects memory in mice

 

The researchers then looked at the effect of exercise on irisin and the brain. In the study's most compelling experiments, the researchers found that mice who swam nearly every day for five weeks did not develop memory impairment despite getting infusions of beta amyloid -- the neuron-clogging, memory-robbing protein implicated in Alzheimer's.

 

Blocking irisin with a drug completely eliminated the benefits of swimming, the researchers also found. Mice who swam and were treated with irisin-blocking substances performed no better on memory tests than sedentary animals after infusions with beta amyloid.

 

Together the findings suggest that irisin could be exploited to find a novel therapy for preventing or treating dementia in humans, Arancio says. His team is now searching for pharmaceutical compounds that can increase brain levels of the hormone or can mimic its action.

 

"In the meantime, I would certainly encourage everyone to exercise, to promote brain function and overall health," he said. "But that's not possible for many people, especially those with age-related conditions like heart disease, arthritis, or dementia. For those individuals, there's a particular need for drugs that can mimic the effects of irisin and protect synapses and prevent cognitive decline."

https://www.sciencedaily.com/releases/2019/02/190208173511.htm

Absentmindedness points to earlier warning signs of silent strokes among people at risk

February 6, 2019

Science Daily/Baycrest Centre for Geriatric Care

Adults who notice that they frequently lose their train of thought or often become sidetracked may in fact be displaying earlier symptoms of cerebral small vessel disease, otherwise known as a 'silent stroke,' suggests a recent study.

 

Researchers uncovered that individuals with damage to the brain's white matter, caused by silent strokes, reported poor attentiveness and being distracted more frequently on day-to-day tasks, according to a recently published paper in the journal Neurobiology of Aging. Despite these complaints, about half of the people with identified white matter damage scored within the normal range on formal laboratory assessments of attention and executive function (a person's ability to plan, stay organized and maintain focus on overall goals).

 

"Our results indicate that in many cases of people who were at a higher risk of silent stroke and had one, they saw a notable difference in their ability to stay focused, even before symptoms became detectable through a neuropsychological test," says Ayan Dey, lead author on the paper and a graduate student at Baycrest's Rotman Research Institute (RRI) and the University of Toronto. "If a person feels this may be the case, concerns should be brought to a doctor, especially if the person has a health condition or lifestyle that puts them at a higher risk of stroke or heart disease."

 

Cerebral small vessel disease is one of the most common neurological disorders of aging. This type of stroke and changes in the brain's blood flow (vascular changes) are connected to the development of vascular dementia and a higher risk of Alzheimer's disease and other dementias.

 

The strokes are "silent" since they don't cause lasting major changes seen with an overt stroke, such as affecting a person's ability to speak or paralysis. Despite a lack of obvious symptoms, cerebral small vessel disease causes damage to the brain's white matter (responsible for communication among regions), which can cause memory and cognitive issues over time.

 

Typically, this type of stroke is uncovered incidentally through MRI scans or once the brain damage has worsened, says Dey.

 

"There are no effective treatments for Alzheimer's disease, but brain vascular changes can be prevented or reduced through smoking cessation, exercise, diet and stress management, as well as keeping one's blood pressure, diabetes and cholesterol under control," says Dr. Brian Levine, senior author on the paper, RRI senior scientist and professor of Psychology and Neurology at the University of Toronto. "With the right diagnosis, these interventions and lifestyle changes give older adults who are at risk for cognitive decline some options for maintaining brain health."

 

The study looked at results from 54 adults (between the ages of 55 to 80), who also possessed at least one risk factor for a stroke, such as high blood pressure, high cholesterol, diabetes, sleep apnea, a history of smoking, past mini strokes and advanced age above 75.

 

Research participants had their brains scanned by MRI and scientists analyzed brain tissue damage, specifically in relation to white matter, to determine injuries caused by cerebral small vessel disease. They also took part in a number of neurocognitive tests and questionnaires that assessed their attention and executive function.

 

Following up on this study, researchers will analyze functional brain imaging and electrical brain activity from participants to look at the differences in brain networks. They hope to uncover why some people are still able to perform well on cognitive assessments, despite damage to the brain.

 

"The question that remains is whether overcoming these changes in the brain is a natural ability some people have or if this is something that can be built up over time," says Dey. "If it's something that can be developed, is it something we can train?"

https://www.sciencedaily.com/releases/2019/02/190206091417.htm

A new culprit in cognitive decline in Alzheimer's disease

Study finds blood protein destroys memory storage sites in the brain and may lead to new treatments

February 5, 2019

Science Daily/Gladstone Institutes

Scientists have shown for the first time that a blood-clotting protein called fibrinogen is responsible for a series of molecular and cellular events that can destroy connections between neurons in the brain and result in cognitive decline.

 

It has long been known that patients with Alzheimer's disease have abnormalities in the vast network of blood vessels in the brain. Some of these alterations may also contribute to age-related cognitive decline in people without dementia. However, the ways in which such vascular pathologies contribute to cognitive dysfunction have largely remained a mystery. Until now, that is.

 

Scientists at the Gladstone Institutes, led by Senior Investigator Katerina Akassoglou, PhD, showed for the first time that a blood-clotting protein called fibrinogen is responsible for a series of molecular and cellular events that can destroy connections between neurons in the brain and result in cognitive decline.

 

Akassoglou and her team used state-of-the-art imaging technology to study both mouse brains and human brains from patients with Alzheimer's disease. They also produced the first three-dimensional volume imaging showing that blood-brain barrier leaks occur in Alzheimer's disease.

 

In their study, published in the scientific journal Neuron, the researchers found that fibrinogen, after leaking from the blood into the brain, activates the brain's immune cells and triggers them to destroy important connections between neurons. These connections, called synapses, are critical for neurons to communicate with one another.

 

Previous studies have shown that elimination of synapses causes memory loss, a common feature in Alzheimer's disease and other dementias. Indeed, the scientists showed that preventing fibrinogen from activating the brain's immune cells protected mouse models of Alzheimer's disease from memory loss.

 

"We found that blood leaks in the brain can cause elimination of neuronal connections that are important for memory functions," explains Akassoglou, who is also a professor of neurology at UC San Francisco (UCSF). "This could change the way we think about the cause and possible cure of cognitive decline in Alzheimer's disease and other neurological diseases."

 

The team showed that fibrinogen can have this effect even in brains that lack amyloid plaques, which are the focus of diverse treatment strategies that have failed in large clinical trials. The researchers showed that injecting even extremely small quantities of fibrinogen into a healthy brain caused the same kind of immune cell activation and loss of synapses they saw in Alzheimer's disease.

 

"Traditionally, the build-up of amyloid plaques in the brain has been seen as the root of memory loss and cognitive decline in Alzheimer's disease," says Mario Merlini, first author of the study and a staff research scientist in Akassoglou's laboratory at Gladstone. "Our work identifies an alternative culprit that could be responsible for the destruction of synapses."

 

The scientists' data help explain findings from recent human studies in which elderly people with vascular pathology showed similar rates of cognitive decline as age-matched people with amyloid pathology. However, patients with both types of pathology had much worse and more rapid cognitive decline. Other studies also identified vascular pathology as a strong predictor of cognitive decline that can act independently of amyloid pathology.

 

"Given the human data showing that vascular changes are early and additive to amyloid, a conclusion from those studies is that vascular changes may have to be targeted with separate therapies if we want to ensure maximum protection against the destruction of neuronal connections that leads to cognitive decline," says Akassoglou.

 

Interestingly, Akassoglou and her colleagues recently developed an antibody that blocks the interaction between fibrinogen and a molecule on the brain's immune cells. In a previous study, they showed this antibody protected mouse models of Alzheimer's disease from brain inflammation and neuronal damage.

 

"These exciting findings greatly advance our understanding of the contributions that vascular pathology and brain inflammation make to the progression of Alzheimer's disease," said Lennart Mucke, MD, co-author of the study and director of the Gladstone Institute of Neurological Disease. "The mechanisms our study identified may also be at work in a range of other diseases that combine leaks in the blood-brain barrier with neurological decline, including multiple sclerosis, traumatic brain injury, and chronic traumatic encephalopathy. It has far-reaching therapeutic implications."

https://www.sciencedaily.com/releases/2019/02/190205115419.htm

Scientists shed light on processes behind age-related decline in brain structures

January 31, 2019

Science Daily/Cardiff University

Aging can cause damage to support cells in the white matter, which in turn may lead to damage in the grey matter of the hippocampus, finds a new study.

 

The discovery gives researchers a new area to focus on in the search for treatments that can protect cognitive function.

 

Claudia Metzler-Baddeley, from Cardiff University's Brain Imaging Research Centre (CUBRIC), said: "The brain is made up of grey and white matter. While grey matter contains neuronal cells, which perform computations in our brain, the white matter contains connections and support cells that help the communication between different areas.

 

"Our new study not only confirms that aging leads to both grey matter decline in the hippocampus and white matter decline in the surrounding area, but also reveals the causal relationship between the two.

 

"Using a method called mediation analysis, we discovered that ageing of the white matter was accounting for ageing of hippocampal grey matter and not the other way around. Our results suggest that damage to the support cells may affect tissue health in the hippocampus, a region important for memory and involved in Alzheimer's disease.

 

"This is an exciting find. If hard-working support cells in the white matter start to misfunction with age, then therapies that protect these support cells may aid in the fight against the damage that ageing can do to our cognitive ability."

 

The study, which looked at the brains of 166 healthy volunteers, was carried out using state-of-the-art brain imaging techniques at CUBRIC and was jointly funded by the Alzheimer's Society and the BRACE Alzheimer's charity.

https://www.sciencedaily.com/releases/2019/01/190131104936.htm

'Bugs' in the gut might predict dementia in the brain

January 30, 2019

Science Daily/American Heart Association

The makeup of bacteria and other microbes in the gut may have a direct association with dementia risk, according to preliminary research to be presented in Honolulu at the American Stroke Association's International Stroke Conference 2019, a world premier meeting for researchers and clinicians dedicated to the science and treatment of cerebrovascular disease.

 

Researchers studying the population of bacteria and microbes in the intestines, known as gut microbiota, have found these "bugs" impact risks for diseases of the heart and more. Japanese researchers studied 128 (dementia and non-dementia) patients' fecal samples and found differences in the components of gut microbiota in patients with the memory disorder suggesting that what's in the gut influences dementia risk much like other risk factors.

 

The analysis revealed that fecal concentrations of ammonia, indole, skatole and phenol were higher in dementia patients compared to those without dementia. But levels of Bacteroides -- organisms that normally live in the intestines and can be beneficial -- were lower in dementia patients.

 

"Although this is an observational study and we assessed a small number of the patients, the odds ratio is certainly high suggesting that gut bacteria may be a target for the prevention of dementia," said Naoki Saji, M.D., Ph.D., study author and vice director of the Center for Comprehensive Care and Research on Memory Disorders, National Center for Geriatrics and Gerontology in Japan.

https://www.sciencedaily.com/releases/2019/01/190130075751.htm

What you eat could impact your brain and memory

January 28, 2019

Science Daily/Iowa State University

High levels of a satiety hormone could decrease a person's likelihood of developing Alzheimer's disease. For individuals who have higher levels of the hormone, their chance of having mild cognitive impairment or Alzheimer's disease decreased by 65 percent.

 

You may be familiar with the saying, "You are what you eat," but did you know the food you eat could impact your memory?

 

Auriel Willette, assistant professor, and his team of researchers in Iowa State University's Department of Food Science and Human Nutrition discovered a satiety hormone that, at higher levels, could decrease a person's likelihood of developing Alzheimer's disease. A paper outlining the results of their study recently was accepted for publication in Neurobiology of Aging.

 

Using data from the Alzheimer's Disease Neuroimaging Initiative (ADNI), the researchers looked at the satiety hormone, Cholecystokinin (CCK), in 287 people. CCK is found in both the small intestines and the brain. In the small intestines, CCK allows for the absorption of fats and proteins. In the brain, CCK is located in the hippocampus, which is the memory-forming region of the brain, Willette said.

 

The researchers found for individuals who have higher CCK levels, their chance of having mild cognitive impairment, a precursor state to Alzheimer's disease, or Alzheimer's disease decreased by 65 percent.

 

"It will hopefully help to shed further light on how satiety hormones in the blood and brain affect brain function," Willette said.

 

Why CCK?

 

Alexandra Plagman, lead author and graduate student in nutritional science, said they chose to focus on CCK because it is highly expressed in memory formation. The researchers wanted to see if there was any significance between levels of CCK and levels of memory and gray matter in the hippocampus and other important areas.

 

They also looked p-tau and tau proteins, which are thought to be toxic to the brain, to see how these might impact CCK and memory. They found that as tau levels increased, higher CCK was no longer related to less memory decline.

 

The researchers hope this study will encourage others to look into the nutritional aspect of diets, versus just looking at caloric intake. Plagman already is looking at how diet impacts an individual's CCK levels through researching fasting glucose and ketone bodies.

 

"By looking at the nutritional aspect, we can tell if a certain diet could prevent Alzheimer's disease or prevent progression of the disease," Plagman said.

 

"The regulation of when and how much we eat can have some association with how good our memory is," Willette added. "Bottom line: what we eat and what our body does with it affects our brain."

https://www.sciencedaily.com/releases/2019/01/190128111705.htm

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