Posts tagged cognition
Articles and news from the latest research reports.
Dietary Flavanols Reverse Age-Related Memory Decline
Dietary cocoa flavanols—naturally occurring bioactives found in cocoa—reversed age-related memory decline in healthy older adults, according to a study led by Columbia University Medical Center (CUMC) scientists. The study, published today in the advance online issue of Nature Neuroscience, provides the first direct evidence that one component of age-related memory decline in humans is caused by changes in a specific region of the brain and that this form of memory decline can be improved by a dietary intervention.
As people age, they typically show some decline in cognitive abilities, including learning and remembering such things as the names of new acquaintances or where they parked the car or placed their keys. This normal age-related memory decline starts in early adulthood but usually does not have any noticeable impact on quality of life until people reach their fifties or sixties. Age-related memory decline is different from the often-devastating memory impairment that occurs with Alzheimer’s, in which a disease process damages and destroys neurons in various parts of the brain, including the memory circuits.
Previous work, including by the laboratory of senior author Scott A. Small, MD, had shown that changes in a specific part of the brain—the dentate gyrus—are associated with age-related memory decline. Until now, however, the evidence in humans showed only a correlational link, not a causal one. To see if the dentate gyrus is the source of age-related memory decline in humans, Dr. Small and his colleagues tested whether compounds called cocoa flavanols can improve the function of this brain region and improve memory. Flavanols extracted from cocoa beans had previously been found to improve neuronal connections in the dentate gyrus of mice.
Dr. Small is the Boris and Rose Katz Professor of Neurology (in the Taub Institute for Research on Alzheimer’s Disease and the Aging Brain, the Sergievsky Center, and the Departments of Radiology and Psychiatry) and director of the Alzheimer’s Disease Research Center in the Taub Institute at CUMC.
A cocoa flavanol-containing test drink prepared specifically for research purposes was produced by the food company Mars, Incorporated, which also partly supported the research, using a proprietary process to extract flavanols from cocoa beans. Most methods of processing cocoa remove many of the flavanols found in the raw plant.
In the CUMC study, 37 healthy volunteers, ages 50 to 69, were randomized to receive either a high-flavanol diet (900 mg of flavanols a day) or a low-flavanol diet (10 mg of flavanols a day) for three months. Brain imaging and memory tests were administered to each participant before and after the study. The brain imaging measured blood volume in the dentate gyrus, a measure of metabolism, and the memory test involved a 20-minute pattern-recognition exercise designed to evaluate a type of memory controlled by the dentate gyrus.
“When we imaged our research subjects’ brains, we found noticeable improvements in the function of the dentate gyrus in those who consumed the high-cocoa-flavanol drink,” said lead author Adam M. Brickman, PhD, associate professor of neuropsychology at the Taub Institute.
The high-flavanol group also performed significantly better on the memory test. “If a participant had the memory of a typical 60-year-old at the beginning of the study, after three months that person on average had the memory of a typical 30- or 40-year-old,” said Dr. Small. He cautioned, however, that the findings need to be replicated in a larger study—which he and his team plan to do.
Flavanols are also found naturally in tea leaves and in certain fruits and vegetables, but the overall amounts, as well as the specific forms and mixtures, vary widely.
The precise formulation used in the CUMC study has also been shown to improve cardiovascular health. Brigham and Women’s Hospital in Boston recently announced an NIH-funded study of 18,000 men and women to see whether flavanols can help prevent heart attacks and strokes.
The researchers point out that the product used in the study is not the same as chocolate, and they caution against an increase in chocolate consumption in an attempt to gain this effect.
Two innovations by the investigators made the study possible. One was a new information-processing tool that allows the imaging data to be presented in a single three-dimensional snapshot, rather than in numerous individual slices. The tool was developed in Dr. Small’s lab by Usman A. Khan, an MD-PhD student in the lab, and Frank A. Provenzano, a biomedical engineering graduate student at Columbia. The other innovation was a modification to a classic neuropsychological test, allowing the researchers to evaluate memory function specifically localized to the dentate gyrus. The revised test was developed by Drs. Brickman and Small.
Besides flavanols, exercise has been shown in previous studies, including those of Dr. Small, to improve memory and dentate gyrus function in younger people. In the current study, the researchers were unable to assess whether exercise had an effect on memory or on dentate gyrus activity. “Since we didn’t reach the intended VO2max (maximal oxygen uptake) target,” said Dr. Small, “we couldn’t evaluate whether exercise was beneficial in this context. This is not to say that exercise is not beneficial for cognition. It may be that older people need more intense exercise to reach VO2max levels that have therapeutic effects.”
Genes exhibit different behaviours in different stages of development
The effect that genes have on our brain depends on our age. These are the findings of a group of researchers from the MedUni Vienna. It has been known for a number of years that particular genetic variations are of importance for the functioning of neural circuits in the brain. Just how these effects differ in the various stages of life has until recently not been fully understood. This international study has been able to demonstrate that genetic variations at different times in our lives can actually have opposite effects on the brain, which provides an explanation for the differences that clinicians observe in the psychiatric symptoms and response to medications of adolescents and adults.
The group of researchers from Vienna, in collaboration with international cooperation partners, has shown that the effect of a psychiatric risk gene on a resting state network in the forebrain depends greatly on the patient’s age.
The human forebrain is crucial for planning and action, which are closely interwoven with concentration, attention and memory functions. The nerve transmitter substance dopamine orchestrates the activity of neurons in the forebrain in order to ensure an ideal level of functioning. The amount of dopamine in the brain is not constant for life, however. Instead, it rises until adolescence and then falls by the time the individual reaches early adulthood to a much lower level. When the dopaminergic control function collapses, serious mental illnesses such as schizophrenia, depression or attention deficit / hyperactivity disorder (ADHD) can result that usually start around the period of transition to adulthood.
For a number of years, doctors have known that a risk gene involved in dopamine metabolism (COMT) can affect neuronal regulation of the forebrain in adults. Carriers of risk gene variants are more prone to dopaminergic mental illness.
The interaction of genes and stages of development
As part of the study, carried out at the MedUni Vienna’s University Department of Psychiatry and Psychotherapy (led by Siegfried Kasper), the study team used magnetic resonance imaging data from a large random sample of over 200 test subjects to analyse the complex interaction between stages of development and genetic variations in the COMT gene and how it affects the resting state network of the forebrain.
Some of the magnetic resonance scans were performed in Vienna (Centre of Excellent, High-Field MR, Department of MR Physics, Head: Ewald Moser) and some as part of an EU project (Institute of Psychiatry, London, Head: Gunther Schumann). Gene analyses (COMT Val158Met) were carried out in Vienna (Univ. Dept. of Laboratory Medicine, Harald Esterbauer and colleagues) or as part of the EU project.
"Our age has a crucial influence on the effects of psychiatric risk genes. A gene that has positive effects during puberty can be bad for us in adulthood," says study leader Lukas Pezawas, describing the results. In the study, adolescents exhibited contrary gene effects on the brain compared to adults.
The study highlights the dynamism of gene effects on brain function throughout the various stages of life such as adolescence or adulthood. “These results are important for understanding the onset of illness in conditions such as schizophrenia, depression or ADHD, which mostly occur at the threshold of adulthood. Our results also show that there are fundamental differences in the dopamine system between adolescents and adults, which we need to take into account in future treatments”, explains Pezawas.
(Source: meduniwien.ac.at)
Scientific evidence does not support the brain game claims
The Stanford Center for Longevity joined today with the Max Planck Institute for Human Development in issuing a statement skeptical about the effectiveness of so-called “brain game” products. Signing the document were 69 scholars, including six from Stanford and cognitive psychologists and neuroscientists from around the world.
Laura Carstensen, a Stanford psychology professor and the director of the Center for Longevity, said as baby boomers enter their golden years, commercial companies are all too often promising quick fixes for cognition problems through products that are unlikely to produce broad improvements in everyday functioning.
"It is customary for advertising to highlight the benefits and overstate potential advantages of their products," she said. "But in the case of brain games, companies also assert that the products are based on solid scientific evidence developed by cognitive scientists and neuroscientists. So we felt compelled to issue a statement directly to the public."
One problem is that while brain games may target very specific cognitive abilities, there is very little evidence that improvements transfer to more complex skills that really matter, like thinking, problem solving and planning, according to the scholars.
While it is true that the human mind is malleable throughout a lifetime, improvement on a single task – like playing computer-based brain games – does not imply a general, all-around and deeper improvement in cognition beyond performing better on just a particular game.
"Often, the cited research is only tangentially related to the scientific claims of the company, and to the games they sell," said Carstensen, the Fairleigh S. Dickinson, Jr. Professor in Public Policy.
Agreeing with this view were the experts who signed the Stanford-Planck consensus statement, which reads in part:
"We object to the claim that brain games offer consumers a scientifically grounded avenue to reduce or reverse cognitive decline when there is no compelling scientific evidence to date that they do. … The promise of a magic bullet detracts from the best evidence to date, which is that cognitive health in old age reflects the long-term effects of healthy, engaged lifestyles."
Activity and cognition
As the researchers point out, the time spent on computer games takes away from other activities like reading, socializing, gardening and exercising that may benefit cognitive functions.
"When researchers follow people across their lives, they find that those who live cognitively active, socially connected lives and maintain healthy lifestyles are less likely to suffer debilitating illness and early cognitive decline," as the statement describes it.
"In psychology," the scientists note, "it is good scientific practice to combine information provided by many tasks to generate an overall index representing a given ability."
The same standards should be applied to the brain game industry, the experts maintain. But this has not been the case, they add.
"To date, there is little evidence that playing brain games improves underlying broad cognitive abilities, or that it enables one to better navigate a complex realm of everyday life," the participants state.
One reason is the so-called “file drawer effect,” which refers to the practice of researchers filing away studies with negative outcomes. For example, brain game studies proclaiming even modest positive results are more likely to be published, cited and publicized than ones that do not produce those affirming results.
The road ahead
In the statement, Carstensen and her fellow scientists offer recommendations for how people should view older adult life and issues like brain games:
- Legitimate research on brain games needs to be replicated and confirmed scientifically across multiple studies in different settings.
- Physical exercise is beneficial to both general and cognitive health.
- No studies have shown that brain games prevent diseases like Alzheimer’s or other forms of dementia.
- Brain games are not like “one shot” vaccines – the gains won’t last long after the end of the activity.
- People can cultivate their cognitive powers by leading physically active, intellectually challenging and socially engaged lives.
The Stanford Center on Longevity’s mission is to redesign long life. The center studies the nature and development of the human life span, looking for innovative ways to use science and technology to solve the problems of people over 50 by improving the wellbeing of people of all ages.
In a battle of brains, bigger isn’t always better
It’s one of those ideas that seems to make perfect sense: the bigger the brain, the more intelligent the creature. While it is generally true, exceptions are becoming increasingly common. Yet the belief persists even among scientists. Most biologists, for example, assume that rats, with larger brains, are smarter than mice. Cold Spring Harbor Laboratory (CSHL) scientists now challenge this belief. They compared mice and rats and found very similar levels of intelligence, a result that could have powerful implications for researchers studying complex behaviors and learning.
Are rats really smarter than mice? The question is more important than it sounds. For more than a decade, rats have been the rodent of choice for scientists studying how the brain arrives at decisions. They are relatively inexpensive to keep and are the subject of extensive protocols for studying cognitive function. Yet the last few years have seen an explosion in the number of genetic tools available to study their smaller cousins, mice. These tools enable scientists to turn genes on and off within specific populations of neurons – specificity that is critical to understanding how complex behaviors arise. Many investigators have shied away from using these new tools, however, believing that mice simply are not as intelligent as rats.
CSHL Professor Anthony Zador and Santiago Jaramillo, Ph.D., were skeptical. “Mice have the potential to greatly accelerate our research. We didn’t want to discount a very powerful option based on anecdotal evidence of their inferiority,” explains Zador.
The team systematically compared how rats and mice learn to perform a moderately challenging auditory task and found that their performance was similar. “This was a task that tested perceptual ability as well as adaptability, and we were very surprised to see that mice and rats performed about the same,” says Jaramillo, a former postdoctoral researcher in the Zador lab who now heads his own lab at the University of Oregon.
The researchers were able to find only one difference: rats learned somewhat faster than mice. According to Zador and Jaramillo, the training protocol, which was developed and optimized specifically for rats, might account for the slight advantage.
The finding of roughly equal intelligence has broad implications for cognition research. “We’ve found that mice, and all the genetic tools available in them, can be used to study the neural mechanisms underlying decision-making, and they might be suitable for other cognitive tasks as well,” says Zador.
(Source: ekaweb02.eurekalert.org)
Cockatoos pick up tool use and manufacture through social learning
Two years ago, we brought you the story of Figaro, a Goffin’s cockatoo that lived at a research center in Vienna. These birds don’t use tools in the wild—Figaro’s minders even argue that the cockatoo’s curved beak makes tool use rather difficult for them.
But Figaro’s environment, which features lots of wired mesh, apparently drove him to some novel behaviors. He was observed splitting off splinters from wooden material, and the bird used them to retrieve objects (generally food or toys) that were on the wrong side of the wire. Figaro was making tools.
Chimps Outplay Humans in Brain Games
We humans assume we are the smartest of all creations. In a world with over 8.7 million species, only we have the ability to understand the inner workings of our body while also unraveling the mysteries of the universe. We are the geniuses, the philosophers, the artists, the poets and savants. We amuse at a dog playing ball, a dolphin jumping rings, or a monkey imitating man because we think of these as remarkable acts for animals that, we presume, aren’t smart as us. But what is smart? Is it just about having ideas, or being good at language and math?
Scientists have shown, time and again, that many animals have an extraordinary intellect. Unlike an average human brain that can barely recall a vivid scene from the last hour, chimps have a photographic memory and can memorize patterns they see in the blink of an eye. Sea lions and elephants can remember faces from decades ago. Animals also have a unique sense perception. Sniffer dogs can detect the first signs of colon cancer by the scents of patients, while doctors flounder in early diagnosis. So the point is animals are smart too. But that’s not the upsetting realization. What happens when, for just once, a chimp or a dog challenges man to one of their feats? Well, for one, a precarious face-off – like the one Matt Reeves conceived in the Planet of the Apes – would seem a tad less unlikely than we thought.
In a recent study by psychologists Colin Camerer and Tetsuro Matsuzawa, chimps and humans played a strategy game – and unexpectedly, the chimps outplayed the humans.
(Image: Shutterstock)
Nature or nurture? It’s all about the message
Were Albert Einstein and Leonardo da Vinci born brilliant or did they acquire their intelligence through effort?
No one knows for sure, but telling people the latter – that hard work trumps genes – causes instant changes in the brain and may make them more willing to strive for success, indicates a new study from Michigan State University.
The findings suggest the human brain is more receptive to the message that intelligence comes from the environment, regardless of whether it’s true. And this simple message, said lead investigator Hans Schroder, may ultimately prompt us to work harder.
“Giving people messages that encourage learning and motivation may promote more efficient performance,” said Schroder, a doctoral student in clinical psychology whose work is funded by the National Science Foundation. “In contrast, telling people that intelligence is genetically fixed may inadvertently hamper learning.”
In past research by Stanford University psychologist Carol Dweck, elementary students performing a task were either praised for their intelligence (“You’re so smart!”) or for their effort (“You worked really hard!”) after correct responses. As the task became harder, children in the first group performed worse after their mistakes compared to the group that had heard effort was important.
The MSU study, which appears online in the journal Biological Psychology, offers what could be the first physiological evidence to support those findings, in the form of a positive brain response. “These subtle messages seem to have a big impact, and now we can see they have an immediate impact on how the brain handles information about performance,” Schroder said.
For the study, two groups of participants read different articles. One article reported that intelligence is largely genetic, while the other said the brilliance of da Vinci and Einstein was “probably due to a challenging environment. Their genius had little to do with genetic structure.”
Participants were instructed to remember the main points of the article and completed a simple computer task while their brain activity was recorded. The findings, in a nutshell:
- The group that read intelligence was primarily genetic paid more attention to their responses, as if they were more concerned with their performance. This extra attention, however, did not relate to performance on trials after errors, suggesting a disconnect between brain and behavior.
- In contrast, those who had read that intelligence was due to a challenging environment showed a more efficient brain response after they made a mistake, possibly because they believed they could do better on the next trial. The more attention these participants paid to mistakes, the faster their responses were on the next trial.
The study does not weigh in on the age-old “nature vs. nurture” debate, Schroder noted. Rather, it investigates the messages about the nature of abilities people are exposed to on a regular basis, from a teacher comforting a student (“It’s OK, not everyone can be a math person.”) to the sports announcer commenting on a player’s skill (“Wow, what a natural!”). These messages are thought to contribute to the attitudes or “mindsets” people hold about their intelligence and abilities.
The research started as part of Schroder’s honors thesis as an undergraduate at MSU working in the Clinical Psychophysiology Lab directed by Jason Moser, MSU assistant professor. Moser co-authored the study along with Tim Moran, an MSU graduate student in cognitive psychology, and Brent Donnellan, a former MSU professor who now works at Texas A&M University.
As an undergraduate and graduate student, Schroder has already co-written nine papers that have appeared in academic journals, including five as lead author. His work is supported by a three-year grant from the NSF’s Graduate Research Fellowship Program.
Researchers publish first study of brain activation in MS using fNIRS
Using functional near infrared spectroscopy (fNIRS), Kessler Foundation researchers have shown differential brain activation patterns between people with multiple sclerosis (MS) and healthy controls. This is the first MS study in which brain activation was studied using fNIRS while participants performed a cognitive task. The article, “Neuroimaging and cognition using functional near infrared spectroscopy (fNIRS) in multiple sclerosis,” was published online on June 11 by Brain Imaging and Behavior. Authors are Jelena Stojanovic-Radic, PhD, Glenn Wylie, DPhil, Gerald Voelbel, PhD, Nancy Chiaravalloti, PhD, and John DeLuca, PhD.
Researchers compared 13 individuals with MS with 12 controls for their performance on a working memory task with four levels of difficulty. Most such studies have employed functional magnetic resonance imaging (fMRI); fNIRS has been used infrequently in clinical populations, and has not been applied previously to neuroimaging research in MS. Studies comparing fMRI findings with those of fNIRS, however, show broad agreement in terms of activation patterns.
Results showed differences in activation between the groups that were dependent on task load. The MS group had an increase in activation at low task difficulty and a decrease in activation at high task difficulty. Conversely, in the control group, activation decreased with low task difficulty and increased with high task difficulty. Performance accuracy was lower in the MS group for low task load; there were no differences between the groups at the higher task loads.
“The data we obtained via fNIRS are consistent with fMRI data for clinical populations. We demonstrated that fNIRS is capable of detecting neuronal activation with a reasonable degree of detail,” noted Glenn Wylie, DPhil, associate director of Neuroscience and the Neuroimaging Center at Kessler Foundation. “We attribute the differences in brain activation patterns to the effort expended during the working memory task rather than to differences in speed of processing,” he added. “Because fNIRS is more portable and easier to use that fMRI, it may offer advantages in monitoring cognitive interventions that require frequent scans.”
In addition to working memory, future research in clinical populations should focus on processing speed and episodic memory, cognitive functions that are also affected in MS.
Train your heart to protect your mind
Exercising to improve our cardiovascular strength may protect us from cognitive impairment as we age, according to a new study by researchers at the University of Montreal and its affiliated Institut universitaire de gératrie de Montréal Research Centre. “Our body’s arteries stiffen with age, and the vessel hardening is believed to begin in the aorta, the main vessel coming out of the heart, before reaching the brain. Indeed, the hardening may contribute to cognitive changes that occur during a similar time frame,” explained Claudine Gauthier, first author of the study. “We found that older adults whose aortas were in a better condition and who had greater aerobic fitness performed better on a cognitive test. We therefore think that the preservation of vessel elasticity may be one of the mechanisms that enables exercise to slow cognitive aging.”
The researchers worked with 31 young people between the ages of 18 and 30 and 54 older participants aged between 55 and 75. This enabled the team to compare the older participants within their peer group and against the younger group who obviously have not begun the aging processes in question. None of the participants had physical or mental health issues that might influence the study outcome. Their fitness was tested by exhausting the participants on a workout machine and determining their maximum oxygen intake over a 30 second period. Their cognitive abilities were assessed with the Stroop task. The Stroop task is a scientifically validated test that involves asking someone to identify the ink colour of a colour word that is printed in a different colour (e.g. the word red could be printed in blue ink and the correct answer would be blue). A person who is able to correctly name the colour of the word without being distracted by the reflex to read it has greater cognitive agility.
The participants undertook three MRI scans: one to evaluate the blood flow to the brain, one to measure their brain activity as they performed the Stroop task, and one to actually look at the physical state of their aorta. The researchers were interested in the brain’s blood flow, as poorer cardiovascular health is associated with a faster pulse wave,at each heartbeat which in turn could cause damage to the brain’s smaller blood vessels. “This is first study to use MRI to examine participants in this way,” Gauthier said. “It enabled us to find even subtle effects in this healthy population, which suggests that other researchers could adapt our test to study vascular-cognitive associations within less healthy and clinical populations.”
The results demonstrated age-related declines in executive function, aortic elasticity and cardiorespiratory fitness, a link between vascular health and brain function, and a positive association between aerobic fitness and brain function. “The link between fitness and brain function may be mediated through preserved cerebrovascular reactivity in periventricular watershed areas that are also associated with cardiorespiratory fitness,” Gauthier said. “Although the impact of fitness on cerebral vasculature may however involve other, more complex mechanisms, overall these results support the hypothesis that lifestyle helps maintain the elasticity of arteries, thereby preventing downstream cerebrovascular damage and resulting in preserved cognitive abilities in later life.”
Study of self-awareness in MS has implications for rehabilitation
A new study of self-awareness by Kessler Foundation researchers shows that persons with multiple sclerosis (MS) may be able to improve their self-awareness through task-oriented cognitive rehabilitation. The study was epublished ahead of print on July 2 in NeuroRehabilitation. Self-awareness is one’s ability to recognize cognitive problems caused by brain injury. This is the first study of self-awareness in MS that includes assessment of online awareness, as well as metacognitive awareness.
Yael Goverover, PhD, OT, is a visiting scientist at Kessler Foundation. She is an associate professor at New York University. Dr. Goverover is a recipient of the National Institute on Disability and Rehabilitation Research Fellowship award (Mary Switzer Award). Drs. Genova, Chiaravalloti and DeLuca are MS researchers at Kessler Foundation.
The researchers assessed 18 people with MS and 16 healthy controls for 2 types of self-awareness - metacognitive knowledge of disabilities (or intellectual awareness) and online awareness (emergent or anticipatory awareness). They also looked at the relationships among self-awareness, functional performance and quality of life (QoL). Assessment involved the Functional Behavior Profile, questionnaires administered before and after functional tasks (purchasing cookies and airline tickets via the Internet) and the Functional Assessment of Multiple Sclerosis measure.
“Results showed that compared with controls, people with MS assessed their actual performance more realistically following completion of a task. This suggests that individuals may be able to improve their self-awareness through more experience with tasks,” noted Nancy Chiaravalloti, PhD, director of Neuropsychology & Neuroscience Research at Kessler Foundation.
"Research that leads to better understanding of types of self-awareness, functional outcomes and QOL will aid the development of effective assessments and rehabilitation interventions,” said Dr. Chiaravalloti. “The association between online awareness and task performance in this study, for example, may have implications for cognitive rehabilitation strategies in the MS population.”
(Source: kesslerfoundation.org)