Posts tagged cognitive function
Articles and news from the latest research reports.
New study examines premature menopause and effects on later life cognition
Premature menopause is associated with long-term negative effects on cognitive function, suggests a new study published today (7 May) in BJOG: An International Journal of Obstetrics and Gynaecology (BJOG).
The average age of menopause is around 50 years in the Western World. Premature menopause refers to menopause at or before 40 years of age, this could be due to a bilateral ovariectomy, (surgically induced menopause)or non-surgical loss of ovarian function (sometimes referred to as ‘natural’ menopause).
The study, based on a sample of 4868 women, used cognitive tests and clinical dementia diagnosis at baseline and after two, four and seven years and aimed to determine whether premature menopause can have an effect on later-life cognitive function. The effects of the type of menopause, whether natural or surgical, and use of hormone treatment were also examined.
Of the 4,868 women in this study, natural menopause was reported by 79% of the women, 10% as a surgical menopause and 11% of women reported menopause due to other causes, such as radiation or chemotherapy. Around 7.6% of the women in the study had a premature menopause and a further 12.8% an early menopause (between the ages of 41 and 45 years). Over a fifth of the women used hormone treatment during the menopause.
Results show that in comparison to women who experienced menopause after the age of 50, those with a premature menopause had a more than 40% increased risk of poor performance on tasks assessing verbal fluency and visual memory and was associated with a 35% increased risk of decline in psychomotor speed (coordination between the brain and the muscles that brings about movement) and overall cognitive function over 7 years. There was no significant association with the risk of dementia.
Furthermore, both premature ovarian failure and premature surgical menopause were associated with a more than two-fold risk of poor verbal fluency. In terms of visual memory, premature ovarian failure was associated with a significantly increased risk of poor performance, and there was a similar trend for premature surgical menopause.
When the potential modifying effect of using hormone treatment at the time of premature menopause was examined, there was some evidence that it may be beneficial for visual memory, but it could increase the risk of poor verbal fluency.
Dr Joanne Ryan, Postdoctoral Research Fellow, Neuropsychiatry: Epidemiological and Clinical Research, Hospital La Colombiere, Montpellier, said:
“Both premature surgical menopause and premature ovarian failure, were associated with long-term negative effects on cognitive function, which are not entirely offset by menopausal hormone treatment.
“In terms of surgical menopause, our results suggest that the potential long-term effects on cognitive function should form part of the decision-making process when considering ovariectomy in younger women.”
Pierre Martin Hirsch, BJOG deputy editor-in-chief added:
“With the ageing population it is important to have a better understanding of the long term effects of a premature menopause on later-life cognitive function and the potential benefit from using menopausal hormone treatment.
“This study adds to the existing evidence base to suggest premature menopause can have a significant impact on cognitive function in later life which healthcare professionals must be aware of.”
(Source: eu.wiley.com)
A third of a million adults in the UK are to be invited to take part in the world’s biggest study of cognitive function.
Investigators Discover How Key Protein Enhances Memory and Learning
Case Western Reserve researchers have discovered that a protein previously implicated in disease plays such a positive role in learning and memory that it may someday contribute to cures of cognitive impairments. The findings regarding the potential virtues of fatty acid binding protein 5 (FABP5) — usually associated with cancer and psoriasis — appear in the May 2 edition of The Journal of Biological Chemistry.
“Overall, our data show that FABP5 enhances cognitive function and that FABP5 deficiency impairs learning and memory functions in the brain hippocampus region,” said senior author Noa Noy, PhD, a professor of pharmacology at the School of Medicine. “We believe if we could find a way to upregulate the expression of FABP5 in the brain, we might have a therapeutic handle on cognitive dysfunction or memory impairment in some human diseases.”
FABP5 resides in many tissues and is especially highly expressed in the brain. Noy and her Case Western Reserve School of Medicine and National Institute on Alcohol Abuse and Alcoholism colleagues particularly wanted to understand how this protein functioned in neurons. They performed imaging studies comparing the activation of a key transcription factor in the brain tissue of normal mice and in FABP5-deficient mice. (Transcription factor is a protein the controls the flow of genetic information). The investigations revealed that FABP5 performs two different functions in neurons. First, it facilitates the degradation of endocannabinoids, which are neurological modulators controlling appetite, pain sensation, mood and memory. Second, FABP5 regulates gene expression, a process that essentially gives cells their marching orders on structure, appearance and function.
“FABP5 improves learning and memory both because it delivers endocannabinoids to cellular machinery that breaks them down and because it shuttles compounds to a transcription factor that increases the expression of cognition-associated genes,” Noy said.
Even though endocannabinoids affect essential physiological processes from appetite to memory, the “cannabinoid” part of the word signifies that these natural biological compounds act similarly to drugs such as marijuana and hashish. Too much endocannabinoid can lead to impaired learning and memory.
In simple terms, FABP5 transports endocannabinoids for processing. FABP5 functions like a bus and carries the brain’s endocannabinoids and their biological products to two stations within the neuron cell. FABP5 captures endocannabinoids entering the neuron and delivers them to an enzyme that degrades them (station 1). Then, that degraded product is picked up by the same protein (FABP5) and shuttled to the cell nucleus — specifically, to a transcription factor within it (station 2). Binding of the degraded product activates the transcription factor and allows it to induce expression of multiple genes. The genes that are induced in this case tell the cells to take steps that promote learning and memory.
Noy and associates also compared memory and learning in FABP5-deficient mice and in normal ones. In one test, both sets of mice repeatedly swam in mazes that had a platform in one established location where they could climb out of the water. During subsequent swims, the wild-type mice reached the platform quickly because they had learned — and remembered — its location. Their FABP5-deficient counterparts took much longer, typically finding the platform’s location by chance.
“In addition to regulating cell growth as in skin and in cancer cells, for example, FABP5 also plays a key role in neurons of the brain,” Noy said. “FABP5 controls the biological actions of small compounds that affect memory and learning and that activate a transcription factor, which regulates neuronal function.”
(Source: casemed.case.edu)
Higher Education Associated With Better Recovery From Traumatic Brain Injury
Better-educated people appear to be significantly more likely to recover from a moderate to severe traumatic brain injury (TBI), suggesting that a brain’s “cognitive reserve” may play a role in helping people get back to their previous lives, new Johns Hopkins research shows.
The researchers, reporting in the journal Neurology, found that those with the equivalent of at least a college education are seven times more likely than those who didn’t finish high school to be disability-free one year after a TBI serious enough to warrant inpatient time in a hospital and rehabilitation facility.
The findings, while new among TBI investigators, mirror those in Alzheimer’s disease research, in which higher educational attainment — believed to be an indicator of a more active, or more effective, use of the brain’s “muscles” and therefore its cognitive reserve — has been linked to slower progression of dementia.
“After this type of brain injury, some patients experience lifelong disability, while others with very similar damage achieve a full recovery,” says study leader Eric B. Schneider, Ph.D., an epidemiologist at the Johns Hopkins University School of Medicine’s Center for Surgical Trials and Outcomes Research. “Our work suggests that cognitive reserve ¬— the brain’s ability to be resilient in the face of insult or injury — could account for the difference.”
Schneider conducted the research in conjunction with Robert D. Stevens. M.D., a neuro-intensive care physician with Johns Hopkins’ Department of Anesthesiology and Critical Care Medicine.
For the study, the researchers studied 769 patients enrolled in the TBI Model Systems database, an ongoing multi-center cohort of patients funded by the National Institute on Disability and Rehabilitation Research. The patients had been hospitalized with a moderate to severe TBI and subsequently admitted to a rehabilitation facility.
Of the 769 patients, 219 — or 27.8 percent — were free of any detectable disability one year after their injury. Twenty-three patients who didn’t complete high school — 9.7 percent of those at that education level — recovered, while 136 patients with between 12 and 15 years of schooling — 30.8 percent of those at that educational level — did. Nearly 40 percent of patients — 76 of the 194 — who had 16 or more years of education fully recovered.
Schneider says researchers don’t currently understand the biological mechanisms that might account for the link between years of schooling and improved recovery.
“People with increased cognitive reserve capabilities may actually heal in a different way that allows them to return to their pre–injury function and/or they may be able to better adapt and form new pathways in their brains to compensate for the injury,” Schneider says. “Further studies are needed to not only find out, but also to use that knowledge to help people with less cognitive reserve.”
Meanwhile, he says, “What we learned may point to the potential value of continuing to educate yourself and engage in cognitively intensive activities. Just as we try to keep our bodies strong in order to help us recover when we are ill, we need to keep the brain in the best shape it can be.”
Adds Stevens: “Understanding the underpinnings of cognitive reserve in terms of brain biology could generate ideas on how to enhance recovery from brain injury.”
(Source: hopkinsmedicine.org)
First brain images of African infants enable research into cognitive effects of nutrition
Brain activity of babies in developing countries could be monitored from birth to reveal the first signs of cognitive dysfunction, using a new technique piloted by a London-based university collaboration.
The cognitive function of infants can be visualised and tracked more quickly, more accurately and more cheaply using the method, called functional near infra-red spectroscopy (fNIRS), compared to the behavioural assessments Western regions have relied upon for decades.
Professor Clare Elwell, Professor of Medical Physics at University College London (UCL), said: “Brain activity soon after birth has barely been studied in low-income countries, because of the lack of transportable brain imaging facilities needed to do this at any reasonable scale. We have high hopes of building on these promising findings to develop functional near infra-red spectroscopy into an assessment tool for investigating cognitive function of infants who may be at risk of malnutrition or childhood diseases associated with low income settings.”
The pioneering study, published this week in Nature Scientific Reports, was performed by a collaboration of researchers from UCL; the London School of Hygiene and Tropical Medicine; the Babylab at Birkbeck, University of London; and the Medical Research Council unit in Gambia. It aimed to investigate the impact of nutrition in resource-poor regions on infant brain development, and was funded by the Bill and Melinda Gates Foundation.
Professor Clare Elwell (UCL Medical Physics & Bioengineering), said: “This is the first use of brain imaging methods to investigate localised brain activity in African infants.
"Until now, much of our understanding of brain development in low income countries has relied upon behavioural assessments which need careful cultural and linguistic translations to ensure they are accurate. Our technology, functional near infrared spectroscopy, can provide a more objective marker of brain activity."
For the studies in the Gambia, babies aged 4–8 months old were played sounds and shown videos of adults performing specific movements, such as playing ‘peek-a-boo’. The fNIRS system monitored changes in blood flow to the baby’s brain and showed that distinct brain regions responded to visual–social prompts, while others responded to auditory-social stimuli. Comparison of the results with those obtained from babies in the UK showed that the responses were similar in both groups.
fNIRS has previously been used to study brain development in UK infants and most recently to investigate early markers of autism during the first few months of life.
Professor Andrew Prentice (Medical Research Council International Nutrition Group, London School of Hygiene and Tropical Medicine) said: “Humans have evolved to survive and succeed on the basis of their large brain and intelligence, but nutritional deficits in early life can limit this success. In order to plan the best interventions to maximise brain function we need tools that can give us an early read out. fNIRS is showing great promise in this respect.”
New research suggests connection between white matter and cognitive health
A multidisciplinary group of scientists from the Sanders-Brown Center on Aging at the University of Kentucky have identified an interesting connection between the health of the brain tissue that supports cognitive functioning and the presence of dementia in adults with Down syndrome.
Published in the Neurobiology of Aging, the study, which focused on detecting changes in the white matter connections of the brain, offers tantalizing potential for the identification of biomarkers connected to the development of dementia, including Alzheimer’s disease.
"We used magnetic resonance imaging to compare the health of the brain’s white matter and how strongly it connects different parts of the brain," explains Elizabeth Head, Ph.D., the study’s senior author. "The results indicate a compelling progression of deterioration in the integrity of white matter in the brains of our study participants commensurate with their cognitive health."
Research team member David Powell, PhD, compared the brain scans of three groups of volunteers: persons with Down syndrome but no dementia, persons with Down syndrome and dementia, and a healthy control group.
Using MRI technologies, brain scans of subjects with Down syndrome showed some compromise in the tissues of brain’s frontal lobe compared to those from the control group. When people with Down syndrome and dementia were compared to people with Down syndrome without dementia, those same white matter connections were even less healthy.
Perhaps the most intriguing aspect of the study was the correlation between the cognitive abilities of participants with Down Syndrome and the integrity of their white matter– those who had higher motor skill coordination and better learning and memory ability had healthier frontal white matter connections.
Persons with Down syndrome are at an extremely high risk for developing Alzheimer’s disease after the age of 40. The team hopes their work might eventually lead to the identification of biomarkers for the development of Alzheimer’s disease in people with Down syndrome and, potentially, extend that to the general population as well.
Head cautions that these results are to some extent exploratory due to the small cohort of 30 participants. But, she says, “If we are able to identify people who, based on biomarkers, have a higher risk of developing Alzheimer’s disease, we might be able to intervene at an earlier point to retard the progression of the disease.”
Green tea is said to have many putative positive effects on health. Now, researchers at the University of Basel are reporting first evidence that green tea extract enhances the cognitive functions, in particular the working memory. The Swiss findings suggest promising clinical implications for the treatment of cognitive impairments in psychiatric disorders such as dementia. The academic journal Psychopharmacology has published their results.
In the past the main ingredients of green tea have been thoroughly studied in cancer research. Recently, scientists have also been inquiring into the beverage’s positive impact on the human brain. Different studies were able to link green tea to beneficial effects on the cognitive performance. However, the neural mechanisms underlying this cognitive enhancing effect of green tea remained unknown.
Better memory
In a new study, the researcher teams of Prof. Christoph Beglinger from the University Hospital of Basel and Prof. Stefan Borgwardt from the Psychiatric University Clinics found that green tea extract increases the brain’s effective connectivity, meaning the causal influence that one brain area exerts over another. This effect on connectivity also led to improvement in actual cognitive performance: Subjects tested significantly better for working memory tasks after the admission of green tea extract.
For the study healthy male volunteers received a soft drink containing several grams of green tea extract before they solved working memory tasks. The scientists then analyzed how this affected the brain activity of the men using magnetic resonance imaging (MRI). The MRI showed increased connectivity between the parietal and the frontal cortex of the brain. These neuronal findings correlated positively with improvement in task performance of the participants. «Our findings suggest that green tea might increase the short-term synaptic plasticity of the brain», says Borgwardt.
Clinical implications
The research results suggest promising clinical implications: Modeling effective connectivity among frontal and parietal brain regions during working memory processing might help to assess the efficacy of green tea for the treatment of cognitive impairments in neuropsychiatric disorders such as dementia.
Running, Cardio Activities in Young Adulthood May Preserve Thinking Skills in Middle Age
Young adults who run or participate in other cardio fitness activities may preserve their memory and thinking skills in middle age, according to a new study published in the April 2, 2014, online issue of Neurology®, the medical journal of the American Academy of Neurology. Middle age was defined as ages 43 to 55.
“Many studies show the benefits to the brain of good heart health,” said study author David R. Jacobs, Jr, PhD, with the University of Minnesota in Minneapolis. “This is one more important study that should remind young adults of the brain health benefits of cardio fitness activities such as running, swimming, biking or cardio fitness classes.”
Cardiorespiratory fitness is a measure of how well your body transports oxygen to your muscles, and how well your muscles are able to absorb the oxygen during exercise.
For the study, 2,747 healthy people with an average age of 25 underwent treadmill tests the first year of the study and then again 20 years later. Cognitive tests taken 25 years after the start of the study measured verbal memory, psychomotor speed (the relationship between thinking skills and physical movement) and executive function.
For the treadmill test, which was similar to a cardiovascular stress test, participants walked or ran as the speed and incline increased until they could not continue or had symptoms such as shortness of breath. At the first test, participants lasted an average of 10 minutes on the treadmill. Twenty years later, that number decreased by an average of 2.9 minutes. For every additional minute people completed on the treadmill at the first test, they recalled 0.12 more words correctly on the memory test of 15 words and correctly replaced 0.92 more numbers with meaningless symbols in the test of psychomotor speed 25 years later, even after adjusting for other factors such as smoking, diabetes and high cholesterol.
People who had smaller decreases in their time completed on the treadmill test 20 years later were more likely to perform better on the executive function test than those who had bigger decreases. Specifically, they were better able to correctly state ink color (for example, for the word “yellow” written in green ink, the correct answer was “green”).
“These changes were significant, and while they may be modest, they were larger than the effect from one year of aging,” Jacobs said. “Other studies in older individuals have shown that these tests are among the strongest predictors of developing dementia in the future. One study showed that every additional word remembered on the memory test was associated with an 18-percent decrease in the risk of developing dementia after 10 years.”
“These findings are likely to help us earlier identify and consequently prevent or treat those at high risk of developing dementia,” Jacobs said.
Study finds link between child’s obesity and cognitive function
A new University of Illinois study finds that obese children are slower than healthy-weight children to recognize when they have made an error and correct it. The research is the first to show that weight status not only affects how quickly children react to stimuli but also impacts the level of activity that occurs in the cerebral cortex during action monitoring.
“I like to explain action monitoring this way: when you’re typing, you don’t have to be looking at your keyboard or your screen to realize that you’ve made a keystroke error. That’s because action monitoring is occurring in your brain’s prefrontal cortex,” said Charles Hillman, a U of I professor of kinesiology and faculty member in the U of I’s Division of Nutritional Sciences.
As an executive control task that requires organizing, planning, and inhibiting, action monitoring requires people to be computational and conscious at all times as they process their behavior. Because these higher-order cognitive processes are needed for success in mathematics and reading, they are linked with success in school and positive life outcomes, he said.
“Imagine a child in a math class constantly checking to make sure she’s carrying the digit over when she’s adding. That’s an example,” he added.
In the study, the scientists measured the behavioral and neuroelectric responses of 74 preadolescent children, half of them obese, half at a healthy weight. Children were fitted with caps that recorded electroencephalographic activity and asked to participate in a task that presented left- or right-facing fish, predictably facing in either the same or the opposite direction. Children were asked to press a button based on the direction of the middle (that is, target) fish. The flanking fish either pointed in the same direction (facilitating) or in the opposite direction (hindering) their ability to respond successfully.
“We found that obese children were considerably slower to respond to stimuli when they were involved in this activity,” Hillman said.
The researchers also found that healthy-weight children were better at evaluating their need to change their behavior in order to avoid future errors.
“The healthy-weight kids were more accurate following an error than the obese children were, and when the task required greater amounts of executive control, the difference was even greater,” he reported.
A second evaluation measured electrical activity in the brain “that occurs at the intersection of thought and action,” Hillman said. “We can measure what we call error-related negativity (ERN) in the electrical pattern that the brain generates following errors. When children made an error, we could see a larger negative response. And we found that healthy-weight children are better able to upregulate the neuroelectric processes that underlie error evaluation.”
Scientists in the Hillman lab and elsewhere have seen a connection between healthy weight and academic achievement, “but a study like this helps us understand what’s happening. There are certainly physiological differences in the brain activity of obese and healthy-weight children. It’s exciting to be able to use functional brain imaging to see the way children’s weight affects the aspects of cognition that influence and underlie achievement,” said postdoctoral researcher and co-author Naiman Khan.
(Source: news.aces.illinois.edu)
Index Detects Early Signs of Deviation from Normal Brain Development
Researchers at Penn Medicine have generated a brain development index from MRI scans that captures the complex patterns of maturation during normal brain development. This index will allow clinicians and researchers for the first time to detect subtle, yet potentially critical early signs of deviation from normal development during late childhood to early adult.
The study, published online in the journal Cerebral Cortex, shows a relationship between cognitive development and physical changes in the developing young brain (aged 8 to 21).
“Our findings suggest that brain imaging via sophisticated MRI scans may be a useful biomarker for the early detection of subtle developmental abnormalities,” said Guray Erus, PhD, a research associate in the department of Radiology at the Perelman School of Medicine at the University of Pennsylvania, and the study’s lead author. “The abnormalities may, in turn, be the first manifestations of subsequent neuropsychiatric problems.”
Among its key findings is the consistency in healthy brain development of young people. The study examined cognitive performance of outliers – adolescents whose brains developed faster or slower than the normal rates. Early maturers performed significantly better than those with delayed brain development in the speed at which they completed certain tasks. The improved speed of performance indicates increased efficiency in neuronal organization and communication. Slower performance in such tests is a precursor to neuropsychiatric disorders, (the research suggests), including adolescent-onset psychosis.
The 14 tests used in the Penn study evaluate a broad range of cognitive functions including abstraction and mental flexibility, attention, working memory, verbal memory, face memory, spatial memory, language reasoning, nonverbal reasoning, spatial processing, emotion identification, and sensorimotor speed.
Penn’s brain development index consolidates a number of complex visual maps derived from sophisticated analysis of MRI scans into a unified developmental template. By looking at an individual’s brain maps in relation to the consolidated findings, researchers can estimate the age of the subject. Subjects whose brain development index was higher than their chronological age had significantly superior cognitive processing speed as measured by the cognitive tests compared to subjects whose brain indices were lower than their actual age.
“This is analogous to producing growth charts used in pediatrics to screen for gross abnormalities of physical development,” said Christos Davatzikos, PhD, professor of Radiology and Electrical and Systems Engineering at Penn and one of the study’s co-senior authors. “We can assess individuals in terms of where they place in relation to the overall trends. While single image maps can be used for an accurate estimation of the age of the subject, the combination of all maps achieves a higher accuracy in age prediction than the accuracy of each map independently.”
Previous studies have outlined normative trajectories of growth for individual brain regions across the lifespan; the Penn study is the first to present a comprehensive index for the entire brain during late childhood, adolescence, and young adulthood — periods when the healthy human brain maturates in a remarkably consistent way, deviations from which possibly signify later neuropsychiatric problems.
The Penn study used a sample of 621 participants in the Philadelphia Neurodevelopmental Cohort, a Grand Opportunity study funded by the National Institute of Mental Health, designed to understand how brain maturation mediates cognitive development and vulnerability to psychiatric illness and how genetics impacts this process.
“All of our young study participants have received a standardized neuropsychiatric evaluation at intake, and all agreed to be contacted for future studies. Some are followed up longitudinally,” said Ruben C. Gur, PhD, director of the Brain Behavior Laboratory at Penn and the study’s other co-senior author. “We can therefore follow those who score low on our index and examine whether interventions such as cognitive remediation can mitigate potential symptoms.”