Posts tagged cognition
Articles and news from the latest research reports.
Social Network Size Linked to Brain Size
As humans, we aren’t born with formidable armaments or defenses, nor are we the strongest, fastest, or biggest species, yet despite this we are amazingly successful. For a long time it was thought that this success was because our enlarged brains allows each of us to be smarter than our competitors: better at abstract thinking, better with tools and better at adapting our behavior to those of our prey and predators. But are these really the most significant skills our brains provide us with?
Another possibility is that we are successful because we can form long-lasting relationships with many others in diverse and flexible ways, and that this, combined with our native intelligence, explains why homo sapiens came to dominate the planet. In every way from teaching our young to the industrial division of labour we are a massively co-operative species that relies on larger and more diverse networks of relationships than any other species.
Study examines effects of growth hormone-releasing hormone on cognitive function
6-Aug-2012
Treatment with growth hormone-releasing hormone appears to be associated with favorable cognitive effects among both adults with mild cognitive impairment and healthy older adults, according to a randomized clinical trial published Online First by Archives of Neurology, a JAMA Network publication.
"Growth hormone-releasing hormone (GHRH), growth hormone and insulinlike growth factor 1 have potent effects on brain function, their levels decrease with advancing age, and they likely play a role in the pathogenesis of Alzheimer disease," the authors write as background information in the study.
To examine the effects of GHRH on cognitive function in healthy older adults and in adults with mild cognitive impairment (MCI), Laura D. Baker, Ph.D., of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues, conducted a randomized, double-blind, placebo-controlled trial in which participants self-administered daily injections of a form of human GHRH (tesamorelin), or placebo.
The authors enrolled 152 adults ranging in age from 55 to 87 years (average age, 68 years) and 137 participants (76 healthy patients and 61 patients with MCI) successfully completed the study. At baseline, at 10 and 20 weeks of treatment, and after a 10-week washout (30 weeks total), the authors collected blood samples and administered parallel versions of cognitive tests.
Among the original 152 patients enrolled in the study, analysis indicated a favorable effect of GHRH on cognition, which was comparable in adults with MCI and healthy older adults. Analysis among the 137 patients who successfully completed the trial also showed that treatment with GHRH had a favorable effect on cognition among both groups of patients. Although the healthy adults outperformed those with MCI overall, the cognitive benefits relative to placebo was comparable among both groups.
Treatment with GHRH also increased insulin like growth factor 1 levels by 117 percent, which remained within the physiological range, and increased fasting insulin levels within the normal range by 35 percent in adults with MCI but not in healthy adults.
"Our results replicate and expand our earlier positive findings, demonstrating that GHRH administration has favorable effects on cognitive function not only in healthy older adults but also in adults at increased risk of cognitive decline and dementia," the authors conclude. "Larger and longer-duration treatment trials are needed to firmly establish the therapeutic potential of GHRH administration to promote brain health in normal aging and ‘pathological aging.’"
Source: EurekAlert!
Musicians’ Brains Might Have an Edge on Aging
It’s been said that music soothes the savage beast, but if you’re the one playing the instrument it might benefit your brain.
A growing body of evidence suggests that learning to play an instrument and continuing to practice and play it may offer mental benefits throughout life. Hearing has also been shown to be positively affected by making music.
Disorders of consciousness: How should clinicians respond to new therapeutic interventions?
August 2, 2012
New tools have confirmed high rates of misdiagnosis of patients with chronic disorders of consciousness, such as the vegetative state. An increasing number of patients’ families wish to use these novel techniques for diagnosis, prognosis, and treatment. An international team of researchers, including Dr. Éric Racine, researcher at the IRCM, analyzed the clinical, social and ethical issues that clinicians are now facing. Their article is published in the August edition of The Lancet Neurology, a renowned journal in the field of clinical neurology.
"Patients with disorders of consciousness have traditionally been regarded as unaware by definition, but findings from recent clinical studies have revealed astounding cases of awareness despite clinical unresponsiveness," explains Dr. Racine, a Montréal neuroethics specialist.
Severe brain injury can leave patients with chronic disorders of consciousness, which are medical conditions that inhibit consciousness. Patients thus have severe motor and cognitive impairments, remain fully dependent on others for all activities of daily living, and have no or very limited means to functionally communicate their thoughts or wishes, depending on their state.
Even with a careful neurological assessment of these types of disorders, some signs of awareness can elude the clinician because the clinical diagnosis relies on the observation of motor signs of awareness, which can be very subtle and fluctuate over time.
New technological developments can now measure brain function both in resting states and in response to simple commands, independent of muscle function, which could help establish a more accurate diagnosis. As a result, diagnostic classifications have been revised and prognostic knowledge is improving. For the first time, therapeutic studies have recently shown the effects of treatment on the improvement of patient responsiveness.
"The medical decision to stop or continue rehabilitation, or to transfer a patient to a long-term care facility can be hard to accept for the family, but one of the most difficult treatment decisions by family members remains whether to continue life-sustaining therapy or to discontinue it and only provide palliative care," says Dr. Racine.
Media coverage of disorders of consciousness has increased and information on the subject is increasingly available to the public. Clinicians such as neurologists, rehabilitation specialists, family doctors, and nurses must answer more requests from patients’ family members for novel diagnostic and therapeutic procedures.
"Clinicians therefore need to be prepared to discuss disorders of consciousness with ethical sensitivity, especially considering that the new procedures remain investigational," adds Dr. Racine. "They must be aware of the level of evidence supporting them and of the unavoidable ethical and social issues involved in responding to requests from patients’ family members."
Provided by Institut de recherches cliniques de Montreal
Source: medicalxpress.com
Donepezil found helpful in dementia with lewy bodies
July 31, 2012
(HealthDay) — For patients with dementia with Lewy bodies (DLB), treatment with 5 or 10 mg/day donepezil is associated with significant cognitive, behavioral, and global function improvements, according to research published in the July issue of the Annals of Neurology.
Etsuro Mori, M.D., Ph.D., of the Tohoku University Graduate School of Medicine in Sendai, Japan, and colleagues conducted a randomized, double-blind, placebo-controlled trial involving 140 patients with DLB who received either placebo or 3, 5, or 10 mg of donepezil hydrochloride per day for 12 weeks (35, 35, 33, and 37 patients, respectively). Cognitive function was measured using the Mini-Mental State Examination (MMSE); behavioral changes were measured using the Neuropsychiatric Inventory; global function was evaluated using the Clinician’s Interview-Based Impression of Change-plus Caregiver Input (CIBIC-plus); and caregiver burden was also assessed.
The researchers found that, compared with placebo treatment, the MMSE scores were significantly better with donepezil 5 mg (mean difference, 3.8) and 10 mg (mean difference, 2.4), but the 3 mg/day dose was not significantly better than placebo (P = 0.017). Donepezil at doses of 3, 5, and 10 mg/day correlated with significant improvements versus placebo on CIBIC-plus. Both the 5 and 10 mg doses of donepezil resulted in significant improvements in behavioral measures. Caregiver burden also improved, but only with the 10 mg/day dose. The safety results were similar among the groups and were consistent with the known profile.
"Donepezil at 5 and 10 mg/day produces significant cognitive, behavioral, and global improvements that last at least 12 weeks in DLB patients, reducing caregiver burden at the highest dose," the authors write. Several authors disclosed financial ties to pharmaceutical companies, including Eisai Co., which funded the study and manufactures donepezil.
Source: medicalxpress.com
Olympics for the Rest of Us: How Ping-Pong Can Help Your Brain
The physical benefits of the Olympic sports are pretty obvious: strength, endurance and agility, to name a few. But did you know they also can help the brain? Mayo Clinic research shows that any exercise that gets the heart pumping may reduce the risk of dementia and mild cognitive impairment — and slow those conditions if they start. Aerobic exercise also can boost your mood.
Your Body Influences Your Preferences
By Matthew Hutson | July 30, 2012
Why we are biased toward things on our dominant side
Image: GETTY IMAGES
If you are right-handed, chances are you will make different choices than your left-handed friends. A series of recent studies shows that we associate our dominant side with good and our nondominant side with bad, preferring products and people that happen to be on our “good” side over those closer to the other half of our body.
The theory of embodied cognition, widely embraced by cognitive scientists in recent years, holds that our abstract ideas are grounded in our physical experiences in the world. (See above: “embraced,” “holds,” “grounded.”) Daniel Casasanto, a psychologist at the New School for Social Research, began to wonder: If our bodies shape our thinking, do people with different bodies think differently? He has been using handedness as a test bed for this body-specific hypothesis.
In a set of studies published in 2009 Casasanto found that right-handers associate right with good and left with bad and that left-handers make the reverse associations. People prefer objects, job candidates and images of alien creatures on their dominant side to those on their nondominant side. In 2010 he reported that presidential candidates (Kerry, Bush, Obama and McCain) gesture with their dominant hands when making positive points and their weak hands to emphasize darker matters. And he has collected data to suggest that lefties hold higher opinions of their flight attendants when seated on the right side of a plane.
To rule out the possibility that this bias is purely genetic, like handedness is, Casasanto handicapped people’s preferred hands. In a 2011 study he had subjects manipulate dominoes while wearing a bulky ski glove on their good hand. Afterward, they showed a bias against things on that side. The results suggest that we look kindly on half the world because we can interact with that side fluently. Make it a hassle, and opinions flip.
Most recently, Casasanto reported in January in Cognitive Science that children as young as six display a handedness bias. Kids were asked which animal in a series of cartoon pairs looked nicer or smarter. The right-handers more often chose the drawing on the right side, and the left-handers more often chose the animal on the left. They also elected to put away their preferred toys in boxes on their dominant side.
“We all walk around with these lopsided bodies and have to interact with our environment in systematically different ways,” Casasanto notes. Given how broadly those interactions can influence our thinking, he says, “body specificity may be shaping our judgments in the real world in ways that we never suspected.”
Source: Scientific American
Piglets substitute for human babies in cognitive science maze test
A team from the Beckman Institute at the University of Illinois is using piglets instead of human babies to try and model the cognitive development of infants.
Human infants cannot be used as laboratory subjects. The idea to use piglets came when one of neuroscientist Rodney Johnson’s former students, who was working for an infant formula company, asked him about finding ways to monitor the differences in cognitive development between breast-fed and formula-fed children.
As a result he and his colleague Ryan Dilger became interested in using the neonatal piglet as a model for human brain development. The growth and development of the piglet brain is similar to that of the human brain — at birth the human brain is 25 percent of adult size. In the first two years of life, it reaches 85 to 90 percent of adult size. The piglet brain grows in a similar way in a shorter time.
They wanted to see whether they could develop tests to look at learning and memory development using these pigs. First of all they developed MRI techniques to quantify the size of the brain, taking measurements at regular intervals.
They then developed a test using a maze to assess piglets’ learning and memory. This turned out to be much more complicated than expected. Johnson said: “When we first started these studies, we used things like Skittles and apple slices as a reward because that’s what people using older pigs had done.”
However, the piglets were used to being fed on infant formula and so had no interest in solid food, nor were they motivated to perform tasks if the reward was the same as their regular food. The solution was to use Nesquik chocolate milk as a reward.
Tests took place in a plus-sign-shaped maze with one arm blocked off to leave a T shape. Piglets were trained to locate the milk reward using visual cues from outside the maze. When they learned how to do this and the reward location was moved, and the pigs were retested to assess learning and working memory.
Having established that the tests can be used to measure cognitive abilities, the team will examine how nutrient deficiencies (such as iron) and infections (such as pneumonia) affect the human brain during this time of early brain growth.
Johnson said: “There is a lot of interest in the concept of programming, the notion that things that occur early in life set that individual up for problems that occur many years later. Because the pig brain grows so much like a human brain, we thought this could be a very attractive model.”
In order to measure changes in the brain they look at neuroinflammation, neuron growth and changes, as well as biochemical in the brain.
The team hopes to receive funding to look at maternal viral infections, where pregnant pigs will be infected with diseases to see how it affects the brain development of their offspring.
Ecstasy Harms Memory With One Year of Recreational Use
New research published online July 25 by the scientific journal Addiction, gives some of the first information available on the actual risk of using ecstasy. It shows that even in recreational amounts over a relatively short time period, ecstasy users risk specific memory impairments. Further, as the nature of the impairments may not be immediately obvious to the user, it is possible people wouldn’t get the signs that they are being damaged by drug use until it is too late.
According to the study, new ecstasy users who took ten or more ecstasy pills over their first year of use showed decreased function of their immediate and short-term memory compared with their pre-ecstasy performance. These findings are associated with damage of the hippocampus, the area of the brain that oversees memory function and navigation. Interestingly, hippocampal damage is one of the first signs of Alzheimer’s disease, resulting in memory loss and disorientation.
Strobe Eyewear Training Improves Visual Memory
ScienceDaily (July 23, 2012) — Stroboscopic training, performing a physical activity while using eyewear that simulates a strobe-like experience, has been found to increase visual short-term memory retention, and the effects lasted 24 hours.
(Credit: Image courtesy of Duke University)
Participants completed a memory test that required them to note the identity of eight letters of the alphabet that were briefly displayed on a computer screen. After a variable delay, participants were asked to recall one of the eight letters. On easy-level trials, the recall prompt came immediately after the letters disappeared, but on more difficult trials, the prompt came as late as 2.5 seconds following the display. Because participants did not know which letter they would be asked to recall, they had to retain all of the items in memory.
"Humans have a memory buffer in their brain that keeps information alive for a certain short-lived period," said Greg Appelbaum, assistant professor of psychiatry at Duke University and first author of the study. "Wearing the strobe eyewear during the physical training seemed to boost the ability to retain information in this buffer."
The strobe eyewear disrupts vision by only allowing the user to see glimpses of the world. The user must adjust their visual processing in order to perform normally, and this adjustment produces a lingering benefit; once participants removed the strobe eyewear, there was an observed boost in their visual memory retention, which was found to last 24 hours.
Earlier work by Appelbaum and the project’s senior researcher, Stephen Mitroff, had shown that stroboscopic training improves visual perception, including the ability to detect subtle motion cues and the processing of briefly presented visual information. Yet the earlier study had not determined how long the benefits might last.
"Our earlier work on stroboscopic training showed that it can improve perceptual abilities, but we don’t know exactly how," says Mitroff, associate professor of psychology & neuroscience and member of the Duke Institute for Brain Sciences. "This project takes a big step by showing that these improved perceptual abilities are driven, at least in part, by improvements in visual memory."
"Improving human cognition is an important goal with so many benefits," said Appelbaum, also a member of the Duke Institute for Brain Sciences. "Interestingly, our findings demonstrate one way in which visual experience has the capacity to improve cognition."
Source: Science Daily