Posts tagged cognitive function
Articles and news from the latest research reports.
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.
Institutional Rearing May Increase Risk for Attention-Deficit Disorder by Altering Cortical Development
Over the past decades, we have seen numerous tragic examples where the failure of institutions to meet the needs of infants for social contact and stimulation has led to the failure of these infants to thrive.
Infancy and childhood are critical life periods that shape the development of the cortex. A generation of research suggests that enriched environments, full of interesting stimuli to explore, promote cortical development and cognitive function. In contrast, deprivation and stress may compromise cortical development and attenuate some cognitive functions.
Young children who are raised in environments of psychosocial neglect, such as those who grow up in institutions for orphaned or abandoned children, are at markedly elevated risk for developing a wide range of mental health problems, including attention-deficit/hyperactivity disorder (ADHD).
Now, new data from the Bucharest Early Intervention Project (BEIP), published in the current issue of Biological Psychiatry, suggests that this type of deprived early environment is associated with drastic changes in brain development in children.
BEIP is a longitudinal study that has followed a sample of children raised from early infancy in institutions in Romania. The authors of the current report used data from 58 of those children and compared it with 22 typically-reared children from the same community. All children underwent a structural imaging scan and were assessed for symptoms of ADHD.
The researchers discovered that children raised in institutional settings exhibited widespread reductions in cortical thickness in multiple brain regions including the prefrontal, parietal, and temporal cortices relative to children raised in families in the community.
The data also revealed that the reduced cortical thickness in several of those same brain regions was associated with greater ADHD symptoms of inattention and impulsivity.
This is consistent with previous research that has implicated those brain regions in regulating attention, memory, and other vital cognitive processes.
"Perhaps most importantly, the new findings indicate that the high rates of ADHD among children raised in these deprived environments are explained, in part, by these atypical patterns of brain development," explained first author Dr. Katie McLaughlin, Assistant Professor at the University of Washington.
"These disturbing data provide a mechanism that links institutional rearing to compromised cortical development," said Dr. John Krystal, Editor of Biological Psychiatry. “They suggest that society may have to choose between investing in enriching institutional environments and enhancing the capacity of these institutions to offer mental health support on the one hand and bearing the cost of ADHD and its impact on social and vocational productivity on the other.”
McLaughlin agrees and added, “The early caregiving environment has lasting effects on brain development in children. Identifying strategies for mitigating these effects is critical for improving mental health and educational outcomes among children raised in deprived environments.”
(Source: elsevier.com)
Sugar Linked to Memory Problems in Adolescent Rats
Studying rats as model subjects, scientists found that adolescents were at an increased risk of suffering negative health effects from sugar-sweetened beverage consumption.
Adolescent rats that freely consumed large quantities of liquid solutions containing sugar or high-fructose corn syrup (HFCS) in concentrations comparable to popular sugar-sweetened beverages experienced memory problems and brain inflammation, and became pre-diabetic, according to a new study from USC. Neither adult rats fed the sugary drinks nor adolescent rats who did not consume sugar had the same issues.
“The brain is especially vulnerable to dietary influences during critical periods of development, like adolescence,” said Scott Kanoski, corresponding author of the study and an assistant professor at the USC Dornsife College of Letters, Arts and Sciences.
Kanoski collaborated with USC’s Ted Hsu, Vaibhav Konanur, Lilly Taing, Ryan Usui, Brandon Kayser, and Michael Goran. Their study, which tested a total of 76 rats, was published online by the journal Hippocampus on Sept. 23.
About 35 to 40 percent of the rats’ caloric intake was from sugar or HFCS. For comparason, added sugars make up about 17 percent of the total caloric intake of teens in the U.S. on average, according to the CDC.
The rats were then tested in mazes that probe their spatial memory ability. Adolescent rats that had consumed the sugary beverages, particularly HFCS, performed worse on the test than any other group – which may be the result of the neuroinflammation detected in the hippocampus, Kanoski said.
The hippocampus is a part of the temporal lobe located deep within the brain that controls memory formation. People with Alzheimer’s Disease and other dementias often suffer damage to the hippocampus.
“Consuming a diet high in added sugars not only can lead to weight gain and metabolic disturbances, but can also negatively impact our neural functioning and cognitive ability.” Kanoski said. Next, Kanoski and his team plant to see how different monosaccharides (simple sugars) and HFCS affect the brain.
(Source: pressroom.usc.edu)
Vitamin D in diet might ease effects of age on memory
If you don’t want to dumb down with age, vitamin D may be the meal ticket.
A boosted daily dosage of the vitamin over several months helped middle-aged rats navigate a difficult water maze better than their lower-dosed cohorts, according to a study published online Monday in the journal Proceedings of the National Academy of Sciences.
The supplement appears to boost the machinery that helps recycle and repackage signaling chemicals that help neurons communicate with one another in a part of the brain that is central to memory and learning.
"This process is like restocking shelves in grocery stores," said study co-author Nada Porter, a biomedical pharmacologist at the University of Kentucky College of Medicine.
Improving Babies’ Language Skills Before They’re Even Old Enough to Speak
In the first months of life, when babies begin to distinguish sounds that make up language from all the other sounds in the world, they can be trained to more effectively recognize which sounds “might” be language, accelerating the development of the brain maps which are critical to language acquisition and processing, according to new Rutgers research.
The study by April Benasich and colleagues of Rutgers University-Newark is published in the October 1 issue of the Journal of Neuroscience.
The researchers found that when 4-month-old babies learned to pay attention to increasingly complex non-language audio patterns and were rewarded for correctly shifting their eyes to a video reward when the sound changed slightly, their brain scans at 7 months old showed they were faster and more accurate at detecting other sounds important to language than babies who had not been exposed to the sound patterns.
“Young babies are constantly scanning the environment to identify sounds that might be language,” says Benasich, who directs the Infancy Studies Laboratory at the University’s Center for Molecular and Behavioral Neuroscience. “This is one of their key jobs – as between 4 and 7 months of age they are setting up their pre-linguistic acoustic maps. We gently guided the babies’ brains to focus on the sensory inputs which are most meaningful to the formation of these maps.”
Acoustic maps are pools of interconnected brain cells that an infant brain constructs to allow it to decode language both quickly and automatically – and well-formed maps allow faster and more accurate processing of language, a function that is critical to optimal cognitive functioning. Benasich says babies of this particular age may be ideal for this kind of training.
“If you shape something while the baby is actually building it,” she says, “it allows each infant to build the best possible auditory network for his or her particular brain. This provides a stronger foundation for any language (or languages) the infant will be learning. Compare the baby’s reactions to language cues to an adult driving a car. You don’t think about specifics like stepping on the gas or using the turn signal. You just perform them. We want the babies’ recognition of any language-specific sounds they hear to be just that automatic.”
Benasich says she was able to accelerate and optimize the construction of babies’ acoustic maps, as compared to those of infants who either passively listened or received no training, by rewarding the babies with a brief colorful video when they responded to changes in the rapidly varying sound patterns. The sound changes could take just tens of milliseconds, and became more complex as the training progressed.
Looking for lasting improvement in language skills
“While playing this fun game we can convey to the baby, ‘Pay attention to this. This is important. Now pay attention to this. This is important,’” says Benasich, “This process helps the baby to focus tightly on sounds in the environment that ‘may’ have critical information about the language they are learning. Previous research has shown that accurate processing of these tens-of-milliseconds differences in infancy is highly predictive of the child’s language skills at 3, 4 and 5 years.”
The experiment has the potential to provide lasting benefits. The EEG (electroencephalogram) scans showed the babies’ brains processed sound patterns with increasing efficiency at 7 months of age after six weekly training sessions. The research team will follow these infants through 18 months of age to see whether they retain and build upon these abilities with no further training. That outcome would suggest to Benasich that once the child’s earliest acoustic maps are formed in the most optimal way, the benefits will endure.
Benasich says this training has the potential to advance the development of typically developing babies as well as children at higher risk for developmental language difficulties. For parents who think this might turn their babies into geniuses, the answer is – not necessarily. Benasich compares the process of enhancing acoustic maps to some people’s wishes to be taller. “There’s a genetic range to how tall you become – perhaps you have the capacity to be 5’6” to 5’9”,” she explains. “If you get the right amounts and types of food, the right environment, the right exercise, you might get to 5’9” but you wouldn’t be 6 feet. The same principle applies here.”
Benasich says it’s very likely that one day parents at home will be able to use an interactive toy-like device – now under development – to mirror what she accomplished in the baby lab and maximize their babies’ potential. For the 8 to 15 percent of infants at highest risk for poor acoustic processing and subsequent delayed language, this baby-friendly behavioral intervention could have far-reaching implications and may offer the promise of improving or perhaps preventing language difficulties.
Compound from hops aids cognitive function in young animals
Xanthohumol, a type of flavonoid found in hops and beer, has been shown in a new study to improve cognitive function in young mice, but not in older animals.
The research was just published in Behavioral Brain Research by scientists from the Linus Pauling Institute and College of Veterinary Medicine at Oregon State University. It’s another step toward understanding, and ultimately reducing the degradation of memory that happens with age in many mammalian species, including humans.
Flavonoids are compounds found in plants that often give them their color. The study of them – whether in blueberries, dark chocolate or red wine - has increased in recent years due to their apparent nutritional benefits, on issues ranging from cancer to inflammation or cardiovascular disease. Several have also been shown to be important in cognition.
Xanthohumol has been of particular interest because of possible value in treating metabolic syndrome, a condition associated with obesity, high blood pressure and other concerns, including age-related deficits in memory. The compound has been used successfully to lower body weight and blood sugar in a rat model of obesity.
The new research studied use of xanthohumol in high dosages, far beyond what could be obtained just by diet. At least in young animals, it appeared to enhance their ability to adapt to changes in the environment. This cognitive flexibility was tested with a special type of maze designed for that purpose.
“Our goal was to determine whether xanthohumol could affect a process we call palmitoylation, which is a normal biological process but in older animals may become harmful,” said Daniel Zamzow, a former OSU doctoral student and now a lecturer at the University of Wisconsin/Rock County.
“Xanthohumol can speed the metabolism, reduce fatty acids in the liver and, at least with young mice, appeared to improve their cognitive flexibility, or higher level thinking,” Zamzow said. “Unfortunately it did not reduce palmitoylation in older mice, or improve their learning or cognitive performance, at least in the amounts of the compound we gave them.”
Kathy Magnusson, a professor in the OSU Department of Biomedical Sciences, principal investigator with the Linus Pauling Institute and corresponding author on this study, said that xanthohumol continues to be of significant interest for its biological properties, as are many other flavonoids.
“This flavonoid and others may have a function in the optimal ability to form memories,” Magnusson said. “Part of what this study seems to be suggesting is that it’s important to begin early in life to gain the full benefits of healthy nutrition.”
It’s also important to note, Magnusson said, that the levels of xanthohumol used in this study were only possible with supplements. As a fairly rare micronutrient, the only normal dietary source of it would be through the hops used in making beer, and “a human would have to drink 2000 liters of beer a day to reach the xanthohumol levels we used in this research.”
In this and other research, Magnusson’s research has primarily focused on two subunits of the NMDA receptor, called GluN1 and GluN2B. Their decline with age appears to be related to the decreased ability to form and quickly recall memories.
In humans, many adults start to experience deficits in memory around the age of 50, and some aspects of cognition begin to decline around age 40, the researchers noted in their report.
(Source: oregonstate.edu)
Down syndrome helps researchers understand Alzheimer’s disease
The link between a protein typically associated with Alzheimer’s disease and its impact on memory and cognition may not be as clear as once thought, according to a new study from the University of Wisconsin-Madison’s Waisman Center. The findings are revealing more information about the earliest stages of the neurodegenerative disease.
The researchers — including lead study author Sigan Hartley, UW-Madison assistant professor of human development and family studies, and Brad Christian, UW-Madison associate professor of medical physics and psychiatry and director of PET Physics in the Waisman Laboratory for Brain Imaging and Behavior — looked at the role of the brain protein amyloid-β in adults living with Down syndrome, a genetic condition that leaves people more susceptible to developing Alzheimer’s. They published their findings in the September issue of the journal Brain.
"Our hope is to better understand the role of this protein in memory and cognitive function," says Hartley. "With this information we hope to better understand the earliest stages in the development of this disease and gain information to guide prevention and treatment efforts."
However, the findings of their study not only may help scientists better understand the condition as it impacts those living with Down syndrome, but they are also relevant to adults without the genetic syndrome.
"There are many unanswered questions about at what point amyloid-β, together with other brain changes, begins to take a toll on memory and cognition and why certain individuals may be more resistant than others," says Hartley.
The UW-Madison scientists, along with collaborators at the University of Pittsburgh, studied 63 healthy adults with Down syndrome, aged 30 to 53, who did not exhibit clinical signs of Alzheimer’s or other forms of dementia. They found that many adults with Down syndrome had high levels of amyloid-β protein but did not suffer the expected negative consequences of the elevated protein.
Alzheimer’s disease is the sixth leading cause of death in the U.S. People with Down syndrome are born with an extra copy of the 21st chromosome, where the gene that codes for the amyloid-β protein resides.
For the study, which was conducted over the course of two days, researchers used magnetic resonance imaging (MRI) and positron emission tomography (PET) scans to capture images of the participants’ brains. Twenty-two of the 63 participants had elevated levels of amyloid-β but showed no evidence of diminished memory or cognitive function when compared to those without elevated levels of the protein. The researchers controlled for differences in age and intellectual level.
Similarly, when assessed as a continuous measure, amyloid-β levels were not tied to differences in memory or cognitive ability, such as changes in visual and verbal memory, attention and language.
(Source: news.wisc.edu)
(Image caption: Shown are fMRI scans across all subjects in the study. The yellow and red areas in Section A represent parts of the brain that are activated while subjects are forming “gist memories” of pictures viewed. Section B represents areas of increased activation, shown in yellow and red, as detailed memories are being formed. Credit: Image courtesy of Jagust Lab)
Researchers find neural compensation in people with Alzheimer’s-related protein
The human brain is capable of a neural workaround that compensates for the buildup of beta-amyloid, a destructive protein associated with Alzheimer’s disease, according to a new study led by UC Berkeley researchers.
The findings, published today (Sunday, Sept. 14) in the journal Nature Neuroscience, could help explain how some older adults with beta-amyloid deposits in their brain retain normal cognitive function while others develop dementia.
“This study provides evidence that there is plasticity or compensation ability in the aging brain that appears to be beneficial, even in the face of beta-amyloid accumulation,” said study principal investigator Dr. William Jagust, a professor with joint appointments at UC Berkeley’s Helen Wills Neuroscience Institute, the School of Public Health and Lawrence Berkeley National Laboratory.
Previous studies have shown a link between increased brain activity and beta-amyloid deposits, but it was unclear whether the activity was tied to better mental performance.
The study included 22 healthy young adults and 49 older adults who had no signs of mental decline. Brain scans showed that 16 of the older subjects had beta-amyloid deposits, while the remaining 55 adults did not.
The researchers used functional magnetic resonance imaging (fMRI) to track the brain activity of subjects in the process of memorizing pictures of various scenes. Afterwards, the researchers tested the subjects’ “gist memory” by asking them to confirm whether a written description of a scene – such as a boy doing a handstand – corresponded to a picture previously viewed. Subjects were then asked to confirm whether specific written details of a scene – such as the color of the boy’s shirt – were true.
“Generally, the groups performed equally well in the tasks, but it turned out that for people with beta-amyloid deposits in the brain, the more detailed and complex their memory, the more brain activity there was,” said Jagust. “It seems that their brain has found a way to compensate for the presence of the proteins associated with Alzheimer’s.”
What remains unclear, said Jagust, is why some people with beta-amyloid deposits are better at using different parts of their brain than others. Previous studies suggest that people who engage in mentally stimulating activities throughout their lives have lower levels of beta-amyloid.
“I think it’s very possible that people who spend a lifetime involved in cognitively stimulating activity have brains that are better able to adapt to potential damage,” said Jagust.
Brain Benefits From Weight Loss Following Bariatric Surgery
Weight loss surgery can curb alterations in brain activity associated with obesity and improve cognitive function involved in planning, strategizing and organizing, according to a new study published in the Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).
Obesity can tax the brain as well as other organs. Obese individuals face a 35 percent higher risk of developing Alzheimer’s disease compared to normal weight people.
Bariatric surgery is used to help people who are dangerously obese lose weight. Bariatric surgery procedures are designed to restrict the amount of food you can eat before you feel full by reducing the stomach’s size or limit the absorption of nutrients by removing part of the small intestine from the path food takes through the digestive tract. Some procedures, such as Roux-en-Y gastric bypass (RYBG) surgery, use a combination of these methods. This study was the first to assess brain activity in women before and after bariatric surgery.
“When we studied obese women prior to bariatric surgery, we found some areas of their brains metabolized sugars at a higher rate than normal weight women,” said one of the study’s authors, Cintia Cercato, MD, PhD, of the University of São Paolo in São Paolo, Brazil. “In particular, obesity led to altered activity in a part of the brain linked to the development of Alzheimer’s disease – the posterior cingulate gyrus. Since bariatric surgery reversed this activity, we suspect the procedure may contribute to a reduced risk of Alzheimer’s disease and other forms of dementia.”
The longitudinal study examined the effect of RYBG surgery on the brain function of 17 obese women. Researchers used positron emission tomography (PET) scans and neuropsychological tests to assess brain function and activity in the participants prior to surgery and six months after the procedure. The same tests also were run once on a control group of 16 lean women.
Before they underwent surgery, the obese women had higher rates of metabolism in certain areas of the brain, including the posterior cingulate gyrus. Following surgery, there was no evidence of this exacerbated brain activity. Their brain metabolism rates were comparable to the activity seen in normal weight women.
After surgery, the obese women also performed better on a test measuring executive function – the brain’s ability to connect past experience and present action – than they did before the procedures. Executive function is used in planning, organizing and strategizing. Five other neuropsychological tests measuring various aspects of memory and cognitive function showed no change following the surgery.
“Our findings suggest the brain is another organ that benefits from weight loss induced by surgery,” Cercato said. “The increased brain activity the obese women exhibited before undergoing surgery did not result in improved cognitive performance, which suggests obesity may force the brain to work harder to achieve the same level of cognition.”
(Image: Getty)
Increased risk of stroke in people with cognitive impairment
People with cognitive impairment are significantly more likely to have a stroke, with a 39% increased risk, than people with normal cognitive function, according to a new study published in CMAJ (Canadian Medical Association Journal).
"Given the projected substantial rise in the number of older people around the world, prevalence rates of cognitive impairment and stroke are expected to soar over the next several decades, especially in high-income countries," writes Dr. Bruce Ovbiagele, Chair of the Department of Neurology, Medical University of South Carolina, Charleston, South Carolina, with coauthors.
Cognitive impairment and stroke are major contributors to disability, and stroke is the second leading cause of death world-wide. Although stroke is linked to the development and worsening of cognitive impairment, it is not known whether the reverse is true. Previous studies that have looked at the link between cognitive impairment and subsequent stroke have been inconsistent in their findings.
The study in CMAJ, by researchers in the United States, Taiwan and South Korea, analyzed data from 18 studies of 121 879 people with cognitive impairment, of whom 7799 later had strokes. Most of the included studies were conducted in North America or Europe.
The researchers observed a significantly higher rate of stroke in people with cognitive impairment than in people with normal cognitive function.
"We found that the risk of future stroke was 39% higher among patients with cognitive impairment at baseline than among those with normal cognitive function at baseline," write the authors. "This risk increased to 64% when a broadly adopted definition of cognitive impairment was used."
Blockage of blood vessels in the brain (brain infarcts), atherosclerosis, inflammation and other vascular conditions are associated with a higher risk of stroke and cognitive impairment and may contribute to the increased risk.
"Cognitive impairment should be more broadly recognized as a possible early clinical manifestation of cerebral infarction, so that timely management of vascular risk factors can be instituted to potentially prevent future stroke events and to avoid further deterioration of cognitive health," conclude the authors.