1. Study suggests another gene that may significantly influence development of dementia and Alzheimer’s

    September 21, 2017 by Ashley

    From the University of Southern California press release:

    The notorious genetic marker of Alzheimer’s disease and other forms of dementia, ApoE4, may not be a lone wolf.

    Researchers from USC and the University of Manchester have found that another gene, TOMM40, complicates the picture. Although ApoE4 plays a greater role in some types of aging-related memory ability, TOMM40 may pose an even greater risk for other types.

    TOMM40 and APOE genes are neighbors, adjacent to each other on chromosome 19, and they are sometimes used as proxies for one another in genetic studies. At times, scientific research has focused chiefly on one APOE variant, ApoE4, as the No. 1 suspect behind Alzheimer’s and dementia-related memory decline. The literature also considers the more common variant of APOE, ApoE3, neutral in risk for Alzheimer’s disease.

    USC researchers believe their new findings raise a significant research question: Has TOMM40 been misunderstood as a sidekick to ApoE4 when it is really a mastermind, particularly when ApoE3 is present?

    “Typically, ApoE4 has been considered the strongest known genetic risk factor for cognitive decline, memory decline, Alzheimer’s disease or dementia-related onset,” said T. Em Arpawong, the study’s lead author and a post-doctoral fellow in the USC Dornsife College of Letters, Arts and Sciences Department of Psychology. “Although prior studies have found some variants of this other gene TOMM40 may heighten the risk for Alzheimer’s disease, our study found that a TOMM40 variant was actually more influential than ApoE4 on the decline in immediate memory – the ability to hold onto new information.”

    Studies have shown that the influence of genes associated with memory and cognitive decline intensifies with age. That is why the scientists chose to examine immediate and delayed verbal test results over time in conjunction with genetic markers.

    “An example of immediate recall is someone tells you a series of directions to get somewhere and you’re able to repeat them back,” explained Carol A. Prescott, the paper’s senior author who is a professor of psychology at USC Dornsife College and professor of gerontology at the USC Davis School of Gerontology. “Delayed recall is being able to remember those directions a few minutes later, as you’re on your way.”

    The study was published in the journal PLOS ONE on Aug. 11.

    Prescott and Arpawong are among the more than 70 researchers at USC who are dedicated to the prevention, treatment and potential cure of Alzheimer’s disease. The memory-erasing illness is one of the greatest health challenges of the century, affecting 1 in 3 seniors and costing $236 billion a year in health care services. USC researchers across a range of disciplines are examining the health, societal and political effects and implications of the disease.

    In the past decade, the National Institute on Aging has nearly doubled its investment in USC research. The investments include an Alzheimer Disease Research Center.

    Tracking memory loss

    For the study, the team of researchers from USC and The University of Manchester utilized data from two surveys: the U.S. Health and Retirement Study and the English Longitudinal Study of Ageing. Both data sets are nationally representative samples and include results of verbal memory testing and genetic testing.

    The research team used verbal test results from the U.S. Health and Retirement Survey, collected from 1996 to 2012, which interviewed participants via phone every two years. The researchers utilized the verbal memory test scores of 20,650 participants, aged 50 and older who were tested repeatedly to study how their memory changed over time.

    To test immediate recall, an interviewer read a list of 10 nouns and then asked the participant to repeat the words back immediately. For delayed recall, the interviewer waited five minutes and then asked the participant to recall the list. Test scores ranged from 0 to 10.

    The average score for immediate recall was 5.7 words out of 10, and the delayed recall scoring average was 4.5 words out of 10. A large gap between the two sets of scores can signal the development of Alzheimer’s or some other form of dementia.

    “There is usually a drop-off in scores between the immediate and the delayed recall tests,” Prescott said. “In evaluating memory decline, it is important to look at both types of memory and the difference between them. You would be more worried about a person who has scores of 10 and 5 than a person with scores of 6 and 4.”

    The first person is worrisome because five minutes after reciting the 10 words perfectly, he or she can recall only half of them, Prescott said. The other person wasn’t perfect on the immediate recall test, but five minutes later, was able to remember a greater proportion of words.

    To prevent bias in the study’s results, the researchers excluded participants who reported that they had received a likely diagnosis of dementia or a dementia-like condition, such as Alzheimer’s. They also focused on participants identified as primarily European in heritage to minimize population bias. Results were adjusted for age and sex.

    The researchers compared the U.S. data to the results of an independent replication sample of participants, age 50 and up, in the English Longitudinal Study of Aging from 2002 to 2012. Interviews and tests were conducted every two years.

    Genetic markers of dementia

    To investigate whether genes associated with immediate and delayed recall abilities, researchers utilized genetic data from 7,486 participants in the U.S. Health and Retirement Study and 6,898 participants in the English Longitudinal Study of Ageing.

    The researchers examined the association between the immediate and delayed recall results with 1.2 million gene variations across the human genome. Only one, TOMM40, had a strong link to declines in immediate recall and level of delayed recall. ApoE4 also was linked but not as strongly.

    “Our findings indicate that TOMM40 plays a larger role, specifically, in the decline of verbal learning after age 60,” the scientists wrote. “Further, our analyses showed that there are unique effects of TOMM40 beyond ApoE4 effects on both the level of delayed recall prior to age 60 and decline in immediate recall after 60.”

    Unlike ApoE4, the ApoE3 variant is generally thought to have no influence on Alzheimer’s disease or memory decline. However, the team of scientists found that adults who had ApoE3 and a risk variant of TOMM40, were more likely to have lower memory scores. The finding suggests that TOMM40 affects memory – even when ApoE4 is not a factor.

    The team suggested that scientists should further examine the association between ApoE3 and TOMM40 variants and their combined influence on decline in different types of learning and memory.

    “Other studies may not have detected the effects of TOMM40,” Prescott said. “The results from this study provide more evidence that the causes of memory decline are even more complicated than we thought before, and they raise the question of how many findings in other studies have been attributed to ApoE4 that may be due to TOMM40 or a combination of TOMM40 and ApoE4.”


  2. ‘Waves’ of neural activity give new clues about Alzheimer’s

    September 18, 2017 by Ashley

    From the SINC press release:

    While unconscious during deep sleep, millions of neurons’ activity travels across the cerebral cortex. This phenomenon, known as slow waves, is related to the consolidation of memory. The European project called SloW Dyn, led by Spanish scientists, has now revealed anomalies in this activity in mice displaying a decline similar to Alzheimer’s.

    During deep sleep, large populations of neurons in the cerebral cortex and subcortical brain structures simultaneously discharge electrical pulses. They are slow oscillations, that travel as ‘waves’ of neural activity from one point to another in the cortex once every one to four seconds.

    “This global rhythmic activity, controlled by the cerebral cortex, is associated with a lack of consciousness,” says Mavi Sanchez-Vives, director of the Neuroscience Systems group at the August Pi i Sunyer Biomedical Research Institute (IDIBAPS, Barcelona), whose research team has suggested that it is the default activity of the cortical circuits.

    These oscillations consolidate memory and synaptic plasticity and maintain metabolic and cellular function, among others. Within the framework of the European SloW Dyn (Slow Wave Dynamics) project which the neuroscientist leads, researchers have now discovered differences in this brain activity between healthy mice and mice with cognitive decline similar to Alzheimer’s due to premature aging.

    “We detected a decrease in the frequency of the oscillations which were also more irregular and had a lower high-frequency content of 15 to 100 hertz,” points out Sanchez-Vives, also from the Catalan Institution for Research and Advanced Studies (ICREA).

    The study, published in the journal Frontiers in Aging Neuroscience, highlights how some of these changes have also been registered in patients with Alzheimer’s disease for which reason, according to the authors, the animal model could help in studying the disease.

    Cause or effect of diseases

    The relationship between slow oscillations and neurodegenerative diseases is twofold. When there are pathologies that disturb cortical circuits, they are often reflected in the disruption of slow waves. “We are studying what those changes tell us about the altered underlying mechanisms,” says the researcher.

    Furthermore, the wave alterations will likely be associated with sleep problems, which may influence the development of a disease. “For example, if slow wave sleep periods are disrupted, cognitive functions such as attention and memory can be negatively affected,” Sanchez-Vives notes.

    In order to measure these oscillations, scientists use EEGs which record a person’s brain activity while sleeping. Throughout the SloW Dyn project, experts will measure the waves of thousands of people and will ascertain how they change with age. The tools which they have developed for this purpose are an instrument that registers brain activity and an app.

    “This will provide massive information about the composition of sleep, the synchronization of brain activity and the anomalies that can occur as a result of aging or specific pathologies,” highlights the scientist. Researchers hope that these records will also give them clues about the therapeutic potential of restoring slow waves when they are impaired.

    Disconnecting consciousness

    SloW Dyn has been given over 660,000 euros in funding and will last 36 months. At present, the international consortium is midway through this period. One of the ultimate objectives is to develop a model that mathematically describes these oscillations and thus be able to make predictions.

    “We are trying to understand a phenomenon which, although seemingly very simple, has the power to disconnect consciousness,” summarises Sanchez-Vives.

    The Pompeu Fabra University (Barcelona), the Italian Institute of Technology, the University of Chicago (USA), the National Centre for Scientific Research (France) and the company Rythm (France) are also participating in the project led by IDIBAPS.

    Within Horizon 2020-the framework programme for funding research in the European Union-, SloW Dyn is part of the Human Brain Project, one of the Flagship Future and Emerging Technology Research Initiatives (FET Flagships).


  3. Sleep may influence an eyewitness’s ability to identify guilty person

    by Ashley

    From the Michigan State University press release:

    Sleep may influence an eyewitness’s ability to correctly pick a guilty person out of a police lineup, indicates a study by Michigan State University researchers.

    Published in PLOS ONE, the research found that eyewitnesses to a crime who sleep before being given a lineup are much less likely to pick an innocent person out of a lineup — at least when the perpetrator is not in the lineup.

    Some 70 percent of wrongful convictions in the United States are related to false eyewitness accounts. This study is the first scientific investigation into how sleep affects eyewitness memory of a crime, said lead author Michelle Stepan, a doctoral student in psychology.

    “It’s concerning that more people aren’t making the correct decision during lineups; this suggests our memories are not super accurate and that’s a problem when you’re dealing with the consequences of the criminal justice system,” Stepan said. “Putting someone in jail is a big decision based on somebody’s memory of a crime.”

    Stepan and Kimberly Fenn, associate professor of psychology and director of MSU’s Sleep and Learning Lab, conducted an experiment in which about 200 participants watched a video of a crime (a man planting a bomb on a rooftop) and then, 12 hours later, viewed one of two computer lineups of six similar-looking people. One lineup included the perpetrator; the other lineup did not.

    Some participants watched the crime video in the morning and viewed a lineup that night, with no sleep in between. Others watched the crime video at night and viewed a lineup the next morning, after sleeping.

    When the perpetrator was not in the lineup, participants who had slept identified an innocent person 42 percent of the time — compared to 66 percent for participants who had not slept.

    “This is the most interesting finding of the study — that individuals are less likely to choose an innocent suspect after a period of sleep when the perpetrator is absent from the lineup,” Fenn said. This is relevant, she added, because false convictions too often stem from an incorrect eyewitness identification of a suspect who did not commit the crime.

    When the perpetrator was in the lineup, there was essentially no difference between the sleep and no-sleep groups’ ability to choose the guilty man. Both groups correctly identified the perpetrator about 50 percent of the time.

    “In other words,” Fenn said, “sleep may not help you get the right guy, but it may help you keep an innocent individual out of jail.”

    The results could reflect both changes in memory strength and decision-making strategies after sleep.

    The researchers believe participants who slept were more likely to use an “absolute strategy,” in which they compare each person in the lineup to their memory of the suspect, while participants who didn’t sleep were more likely to use a “relative strategy,” in which they compare the people in the lineup to each other to determine who most resembles the perpetrator relative to the others.

    Using a relative strategy is believed to increase false identifications relative to an absolute strategy in perpetrator-absent lineups, Stepan said.

    “These findings tell us that sleep likely impacts memory processes but that it might also impact how people search through a lineup, and those search strategies might be a critical factor when the perpetrator is not in the lineup,” she said.

    Fenn noted that the key findings of the study have since been replicated.

    The MSU team is conducting research that further explores how sleep may directly or indirectly affect eyewitness memory.


  4. Study looks at biological origins of memory deficits in schizophrenia

    September 17, 2017 by Ashley

    From the Zuckerman Institute at Columbia University press release:

    A team of Columbia scientists has found that disruptions to the brain’s center for spatial navigation — its internal GPS — result in some of the severe memory deficits seen in schizophrenia. The new study in mouse models of the disorder marks the first time that schizophrenia’s effects have been observed in the behavior of living animals — and at the level of individual brain cells — with such high-resolution, precision and clarity. The findings offer a promising entry point for attacking a near-universal and debilitating symptom of schizophrenia, memory deficits, which has thus far withstood all forms of treatment.

    The results of this study were published in Nature Neuroscience.

    “An almost intractably complex disorder, schizophrenia is nearly impossible to fully treat — in large part because it acts as two disorders in one,” said Joseph Gogos, MD, PhD, a principal investigator at Columbia’s Mortimer B. Zuckerman Mind Brain Behavior Institute and the paper’s co-senior author. “On one hand, you have paranoia, hallucinations and delusions; while on the other you have severe memory deficits. Antipsychotic drugs, which treat the first class of symptoms, are entirely ineffective when dealing with the second. The reasons for this are simple: we do not yet understand what happens in the brains of schizophrenia patients.

    Cracking schizophrenia’s code must therefore start with deciphering its biological origins, says Dr. Gogos, who is also professor of physiology, cellular biophysics and neuroscience at Columbia University Medical Center (CUMC). This has led to a recent focus on the memory impairments that are so common among schizophrenia patients. In this new study, Dr. Gogos teamed up with Attila Losonczy, MD, PhD, a fellow Zuckerman Institute principal investigator, to investigate episodic memory, which is severely impaired in cases of schizophrenia.

    “Episodic memory is the brain’s repository of information about the past; a way of traveling backwards to recall a specific moment in time,” said Dr. Losonczy, who was also a senior author. “This type of memory is critical for learning about and functioning in everyday life.”

    For this study, the team focused on a brain region called CA1, located in the hippocampus, which plays a role in both navigation and in episodic memory. Physical alterations to CA1 have been previously reported among schizophrenia patients. CA1 is home to place cells, which collectively form internal maps in the brain critical for navigating one’s present surroundings. The CA1 place cells also encode the spatial aspects of episodic memories, such as where you were when you last saw your best friend, or the place your parents always kept the holiday decorations.

    “Recent advances in imaging technologies now give us the power to watch the activity of hundreds of place cells in the CA1 in real time while an animal forms and recalls memories,” said Dr. Losonczy, who is also an associate professor of neuroscience at CUMC. “We developed experiments to record CA1 activity in mice that were genetically modified to mimic schizophrenia, and compared them to normal, healthy mice.”

    The researchers placed both groups of animals on a treadmill under a high-resolution, two-photon microscope, where they were exposed to a variety of sights, sounds and smells (including a water reward placed at unmarked locations on the treadmill). These experiments were designed to test the animals’ ability to navigate a new environment, remember how to navigate a familiar one and adapt quickly when that environment was altered.

    The two groups of mice showed striking differences in behavior and in cell activity. While both groups could successfully navigate a new environment, the schizophrenia-like mice had more trouble remembering familiar environments from day to day, as well as adapting when aspects of that environment changed. By simultaneously tracking the animals’ place cells via the two-photon microscope, the team spotted the difference.

    “When the healthy mice approached something familiar, such as water, their place cells fired with increasing intensity, and then quieted down as the animals moved away,” explained Dr. Losonczy. “And when we moved the location of the water, and gave the animals a chance to relearn where it was, the activity of their place cells reflected the new location.”

    But the brains of the schizophrenia-like mice were different. Their place cells did not shift when the water reward was moved. The brain cells’ lack of adaptability, the scientists argue, could reflect a key and more general mechanism of memory deficits in schizophrenia. It could also represent a new target for drug intervention.

    “These studies are helping to build an understanding of a disorder that has remained a biological mystery,” said Dr. Gogos. “By pinpointing schizophrenia’s many causes, we are opening up multiple points of intervention to slow, halt and even prevent the disorder — which stands to dramatically improve the lives of patients and their families.”


  5. New possibility of studying how Alzheimer’s disease affects the brain at different ages

    September 16, 2017 by Ashley

    From the Lund University press release:

    Alzheimer’s disease can lead to several widely divergent symptoms and, so far, its various expressions have mainly been observed through the behaviour and actions of patients. Researchers at Lund University in Sweden have now produced images showing the changes in the brain associated with these symptoms — a development which increases knowledge and could facilitate future diagnostics and treatment.

    Symptoms vary in cases of Alzheimer’s disease and often relate to the phase of life in which the disease first occurs. People who become ill before the age of 65 often suffer early on from diminished spatial perception and impaired orientation. Elderly patients more often suffer the symptoms traditionally associated with the disease: above all, memory impairment.

    “Now we have a tool which helps us to identify and detect various sub-groups of Alzheimer’s disease. This facilitates the development of drugs and treatments adapted to various forms of Alzheimer’s,” explains Michael Schöll, researcher at Lund University and the University of Gothenburg.

    Diagnostics could also be facilitated, mainly among younger patients in whom it is particularly difficult to arrive at a correct diagnosis.

    Confident in approval for clinical use

    The findings, published in the journal Brain, are based on studies of around 60 Alzheimer’s patients at Skåne University Hospital and a control group consisting of 30 people with no cognitive impairment.

    Once Alzheimer’s disease has taken hold, it gradually results in the tau protein, present in the brain, forming lumps and destroying the transport routes of the neurons. This can be clearly detected with the new imaging method.

    The method includes a device known as a PET camera and a trace substance, a particular molecule, which binds to tau. The imaging method is currently only used in research, where the current study is one of several contributing to increased knowledge about the disease:

    “The changes in the various parts of the brain that we can see in the images correspond logically to the symptoms in early onset and late onset Alzheimer’s patients respectively,” explains Oskar Hansson, professor of neurology at Lund University and consultant at Skåne University Hospital.

    Oskar Hansson believes that the imaging method will be in clinical use within a few years.


  6. A decline in navigational skills could predict neurodegenerative disease

    September 14, 2017 by Ashley

    From the Cell Press press release:

    Changes in how humans map their surroundings and construct and follow directions as they age have been understudied compared to effects on memory and learning. However, age-related declines in navigational ability are independent of those more well-known cognitive downturns, and could form the basis for tools for the early diagnosis of Alzheimer’s disease. Researchers discuss this possibility in a review published August 30 in the journal Neuron.

    “In humans, navigation is much more cumbersome to research than learning or memory,” says Thomas Wolbers, a neuroscientist specializing in aging and cognition at the German Center for Neurodegenerative Diseases. “But it has such a dramatic impact on everyday life, and the key structures of the ‘navigational network’ in the brain are very sensitive to both ordinary healthy aging and pathological factors.”

    Currently, Alzheimer’s disease is diagnosed based on an individual’s medical history, genetic risk factors, and performance on tests that measure memory, language, and reasoning impairments. Wolbers and his colleagues from the United States and the United Kingdom suggest that navigational impairments are among the earliest signs of the Alzheimer’s progression. Healthy older individuals, for instance, strongly prefer to map objects and landmarks relative to their body position (an egocentric strategy) rather than in relation to external objects such as global landmarks or boundaries (an allocentric strategy). This strategic bias makes it much more difficult for them to learn the spatial layout of an environment and can thus reduce their mobility, a worrisome sign in younger people.

    “It can take up to 10 years after the onset of Alzheimer’s for someone to show abnormal results on the standard cognitive tests that are available today, and that’s 10 years that you’ve lost for treating it, should an effective therapy come along down the road,” says Wolbers. “This is where navigation-based diagnostics could contribute, by reducing that window.”

    Navigational testing is held back by a pair of obstacles, though both are receding. The first is the lack of standard tests for navigational tasks and population norms with which to evaluate results. More-affordable and portable virtual reality technology is making standardized test conditions possible, however, while co-author Jan Wiener (@Jan_Wiener) of the United Kingdom’s Bournemouth University is one of the scientists behind the mobile app Sea Hero Quest, a game designed to collect population data on navigation decisions for dementia research.

    The second holdup is that navigational abilities vary wildly from person to person, more so than for memory or other cognitive functions, Wolbers says. An effective diagnostic tool might need to be longitudinal, tracking an individual’s navigation behaviors at different points in time throughout their life and looking for signs of early or accelerated decline. “We need longitudinal human data to be able to definitively say whether a change in navigational function can be used to predict whether Alzheimer’s or any other neurodegenerative disease will develop later on,” Wolbers says.

    With such data and the improved virtual reality setups, the researchers conclude that a navigational test battery analogous to those used for memory and learning will be feasible. For now, Wolbers suggests that people train and use the navigational skills hardwired into their brains, especially in an age of commonplace in-car and handheld GPS technology.

    “There is growing evidence that if you rely too much on that technology it can have a detrimental effect on your navigational ability and in the long term may even be a risk to develop pathological conditions,” he says.


  7. Imagining an action-consequence relationship can boost memory

    September 13, 2017 by Ashley

    From the Baycrest Centre for Geriatric Care press release:

    The next time you hear about the possibility of rain on the weather forecast, try imagining the umbrella tip being lodged in your home’s door lock, blocking you from locking it. This mental exercise could prevent you from leaving home without an umbrella.

    Imagining an action between two objects (the umbrella being lodged in the door lock) and a potential consequence (not being able to lock the door) may help people improve their memory for relationships with other objects, according to a recent Baycrest Health Sciences study published in the Memory & Cognition journal.

    This finding is part of an in-depth study into a natural memory strategy — termed “unitization” — that was used by an individual with amnesia, D.A., who was able to create new memories despite his condition.

    Better understanding of this strategy could allow it to be used in personalized memory rehabilitation to help older adults and those with amnesia bypass gaps in their abilities, says Dr. Jennifer Ryan, senior scientist at Baycrest’s Rotman Research Institute.

    “Previous research has shown that imagining two objects fusing into one will help people work around these memory deficits; but our work demonstrated that understanding the relationship between the two items is also important,” says Dr. Ryan, who is also a psychology and psychiatry professor at the University of Toronto. “We know that cognitive function is impaired during aging and this strategy could be one workaround for minor memory problems, depending on what you need to achieve.”

    The study evaluated the performance of 80 healthy older adults (between the ages of 61 to 88) on a memory task. The group was first trained and tested on the task to gather initial results. They were then either taught one of the three individual features of unitization (fusion, motion, action/consequence) or the overall unitization strategy. After learning these new approaches, participants were tested again to see if this helped their performance.

    Older adults trained to improve their memory using only the action/consequence feature of unitization saw the greatest memory improvements.

    “We are trying to understand what’s important to unitization and what people need to learn in order to benefit,” says Dr. Ryan. “There is no single strategy that will fix your memory, but one method may be more be suitable than another.”

    Next steps for the research will be to explore how the brain’s systems support different memory strategies. With additional funding, researchers could explore incorporating this memory strategy with a personalized brain rehabilitation program for older adults.

    This research was supported by the Canadian Institutes of Health Research, the Ontario Ministry of Health and Long Term Care and the Canada Research Chairs Program.


  8. Severe stress behind self-perceived memory problems

    September 11, 2017 by Ashley

    From the University of Gothenburg press release:

    Stress, fatigue, and feeling like your memory is failing you. These are the symptoms of a growing group of patients studied as part of a thesis at Sahlgrenska Academy. Result — They may need help, but they are rarely entering the initial stages of dementia.

    “We are seeing a growing number of people who are seeking help because of self-perceived cognitive problems, but have no objective signs of disease despite thorough investigation,” says Marie Eckerström, doctoral student at the Institute of Neuroscience and Physiology and licensed psychologist at the Memory Unit of Sahlgrenska University Hospital.

    The influx of this particular group of patients, which currently represents one-third of the individuals who come to the unit, has increased the need for knowledge of who they are. In her work, Marie Eckerström followed a few hundred of them, both women and men, over an average of four years.

    They are usually highly educated professionals who are relatively young in this context, between the ages of 50 and 60. When tested at the hospital, their memory functions are intact. But, in their everyday environment where they are under pressure to constantly learn new things, they think things just are not working right.

    The correlation between self-perceived memory problems and stress proved to be strong. Seven out of ten in the group had experiences of severe stress, clinical burnout, or depression.

    “We found that problems with stress were very common. Patients often tell us they are living or have lived with severe stress for a prolonged period of time and this has affected their cognitive functions to such an extent that they feel like they are sick and are worried about it. In some cases, this is combined with a close family member with dementia, giving the patient more knowledge but also increasing their concern,” says Marie Eckerström.

    The memory unit investigates suspicions of the early stages of dementia in those who seek help. Research is conducted in parallel to this.

    “We primarily investigate suspected dementia. If we are able to rule this out, then the patient does not remain with us. But, there are not so many places such patients can turn and they seem to fall between the cracks.”

    Perceived memory problems are common and may be an early sign of future development of dementia. For those in the studied group who also had deviating biomarkers in their cerebrospinal fluid (beta-amyloid, total-tau and phospho-tau), the risk of deteriorating and developing dementia was more than double. However, the majority demonstrated no signs of deterioration after four years.

    “These individuals have no objective signs of dementia. The issue instead is usually stress, anxiety or depression,” says Marie Eckerström.

    One out of ten with only self-perceived memory problems developed dementia during the investigated period. According to Marie Eckerström, this is a higher percentage than the population in general, but is still low.

    “It is not a matter of just anyone who has occasional memory problems in everyday life. It is more a matter of individuals who sought medical attention to investigate whether they are developing serious problems,” states Marie Eckerström.


  9. Distractions diminish people’s ability to remember, but important facts still stick

    September 6, 2017 by Ashley

    From the University of California – Los Angeles press release:

    “In a world of computers and iPhones, it’s rare that we’re fully focused,” said Alan Castel, a UCLA professor of psychology.

    But how much do all of those distractions diminish our ability to remember? A new study led by Castel and Catherine Middlebrooks, a UCLA graduate student, found that while divided attention does impair memory, people can still selectively focus on what is most important — even while they’re multitasking.

    In one experiment, the researchers showed 192 students 120 words, divided into six groups of 20 words each. Each word was visible on a computer screen for three seconds, and each was paired with a number from 1 to 10. Researchers explained to the students that they would receive scores based on the point value of each word they remembered, making the words with high point values “more important” than the others.

    The participants, all UCLA students, were assigned to one of four groups: One group gave the task their undivided attention. For the second group, researchers played audio of a voice reading numbers from one to 9 while students were viewing the words and their numeric values; students were told to press the space bar on their computer keyboard every time they heard three consecutive odd numbers.

    (Having to juggle those two tasks proved very distracting: Each participant heard eight sequences of three odd numbers, but on average, they identified only 1.87 of the eight.)

    A third group of participants heard familiar pop songs by Katy Perry, Maroon 5, Lady Gaga and Rihanna while they viewed the words. And a fourth group was asked to watch the words while listening to pop songs they hadn’t heard before.

    After each set of 20 words, participants were asked to type as many of the words as they could remember. The researchers calculated a total score for each student after each set of 20 words based on the number on the screen when each word appeared. So, if they remembered the word “twig,” which appeared on screen at the same time as a 10, and “corner,” which appeared with a 6, the participant would receive 16 points. The researchers then repeated the process for each student five times, taking them through all 120 words.

    The researchers found that the first group of participants — those who viewed the words and numbers with no distractions — recalled an average of eight words from each set of 20, while those who were distracted by having to listen for consecutive odd numbers recalled an average of just five words. Both groups of students who listened to music while watching their screens remembered the words almost as well as the group of undistracted students.

    But the scientists also found that multitasking did not affect students’ ability to recall the information they were told was most important — the highest value words. Participants in all four groups were nearly five times as likely to recall a 10-point word as they were to remember a one-point word.

    “Everybody consistently prioritized the high-value words and shifted their attention towards those,” said Middlebrooks, the study’s lead author. “They all came to the realization that they needed to remember what is the most valuable, even though some were distracted and some weren’t.”

    The researchers set up a second, similar experiment with 96 other students — showing each participant six sets of 20 words, each with a numeric value from 1 to 10, but this time changing the distractions.

    Again, one group of students viewed the words without any disruptions. But for the other three groups, the researchers played a series of tones: one group was told to identify whether each tone was the same as the previous one, another was told to indicate whether two tones played one after the other were the same pitch or not, and the final group was told to identify each sound as high-pitched or low-pitched.

    As in the first experiment, students who weren’t distracted remembered an average of eight words from each set of 20. Those who were distracted by the other tasks remembered an average of about five out of every 20 — and the information they forgot tended to be the “less important” words. Participants in all four groups were again nearly five times more likely to recall a 10-point word than a one-point word.

    “The data are very clear in showing that with divided attention, we don’t remember as much, but we are still able to focus on what’s most important,” Castel said.

    The researchers also found that students’ ability to remember information improved as the experiments progressed: In both studies, students in all four groups generally remembered more words by the sixth round of 20 words than they did in the first set.

    Middlebrooks recommends that people who are studying or learning new information avoid distractions as much as possible.

    “All is likely not lost if you’re occasionally interrupted by a text or if someone nearby turns on music while you’re studying,” she said. “Our world is filled with tantalizing distractions, and we seem to adapt by being selectively focused.”

    The research, which is published in the August issue of Psychological Science, was funded by the National Institute on Aging. Tyson Kerr, a former UCLA undergraduate student, is a co-author of the paper.


  10. Neurons involved in learning, memory preservation less stable, more flexible than once thought

    September 2, 2017 by Ashley

    From the Harvard Medical School press release:

    The human brain has a region of cells responsible for linking sensory cues to actions and behaviors and cataloging the link as a memory. Cells that form these links have been deemed highly stable and fixed.

    Now, the findings of a Harvard Medical School study conducted in mice challenge that model, revealing that the neurons responsible for such tasks may be less stable, yet more flexible than previously believed.

    The results, published Aug. 17 in the journal Cell, cast doubt on the traditional notion that memory formation involves hardwiring information into the brain in a fixed and highly stable pattern.

    The researchers say their results point to a critical plasticity in neuronal networks that ensures easier integration of new information. Such plasticity, the researchers said, allows neuronal networks to more easily incorporate new learning, eliminating the need to form new links to separate neurons every time. Furthermore, they said, once a memory is no longer needed, neurons can be more easily reassigned to other important tasks.

    “Our experiments point to far less stability in neurons that link sensory cues to action than we would have expected and suggest the presence of much more flexibility, and indeed a sort of neuronal efficiency,” said study senior author Chris Harvey, an assistant professor of neurobiology at Harvard Medical School. “We believe this trade-off ensures the delicate balance between the ability to incorporate new information while preserving old memories.”

    The Harvard Medical School study involved experiments with mice repeatedly running through a virtual maze over the course of a month. Analyzing images of brain activity in a brain region involved in navigational decision making, the researchers noted that neurons did not stabilize into a pattern. Instead, the set of neurons forming the mice’s maze-running memories kept changing for the duration of the study. In fact, neurons kept switching roles in the memory pattern or left it altogether, only to be replaced by other neurons.

    “Individual neurons tended to have streaks where they’d do the same thing for a few days, then switch,” Harvey said. “Over the course of weeks, we began to see shifts in the overall pattern of neurons.”

    The experiments are part of the research team’s ongoing efforts to unravel the mysteries of memory formation and, specifically, how the brain captures external cues and behaviors to perform recurring tasks such as navigating a space using landmarks. Imagine a person driving a familiar route to the grocery store who sees the bank and turns right at that corner without even having to think about it consciously.

    To mimic that process, mice in the study were trained to run down a virtual passage — a computer-generated maze displayed on large screens in front of a treadmill — and turn right if they were given a black cue or left if they were given a white cue. Researchers imaged hundreds of neurons in the part of the brain responsible for spatial decision making as the mice were galloping down the virtual maze.

    Once the navigational links were firmly established in the mice’s brains over the course of a few weeks, the researchers expected the activity of the neurons to look the same from day to day. During maze runs that occurred within 24 hours of each other that was, indeed, the case. Neurons that activated in response to the white cue could be distinguished from neurons that activated in response to the black cue. However, over the course of several weeks the line between cues in individual neurons blurred and the memory pattern began to drift across neurons, the researchers observed. A neuron that had been associated with the black cue would lose its specialization and be replaced by another, or it might even become associated with the opposite white cue. This came as a surprise to the researchers.

    “We were so sure that the neurons would be doing the same thing every day that we designed the study expecting to use the stable pattern as a baseline,” said study first author Laura Driscoll, a graduate student in the neurobiology department. “After we realized the neurons were changing roles, we had to rethink parts of the study.”

    The researchers tested how the pattern changed when they added shapes as a third cue while the mice were navigating the maze. After some reassignment of individual neurons as the mice learned the new cue, the researchers found very little change to the overall activity pattern. This finding supports the idea that networks of neurons storing memories stay flexible in order to incorporate new learning, the researchers say.

    The researchers hypothesize that neuronal stability may differ across various brain regions, likely depending on how often the skill or memory they encode needs to be modified. For a task like navigation, which frequently requires the brain to incorporate new information, it would make sense that the neurons remain flexible, Harvey said. However, more instinctual physical responses, such as blinking, may be hardwired with little neuronal drift over time.

    The results provide a fascinating early glimpse into the complexities of memory formation, Driscoll said. To elucidate the big picture of memory formation and storage across brain regions, researchers say they hope to study other areas of the brain involved with different types of decision-making and memories.

    “I hope this research inspires people to think of memory as something that is not static,” Harvey said. “Memories are active and integrally connected to the process of learning.”