The size of a small part of the brain, right behind the eyes, is connected with a person’s ability to gauge how likely they are to be right about factual questions, according to a study published in Science last week. This faculty is important in many real-world decisions; it can make the difference between relying on our mistaken judgment and asking for help if we realize we might be wrong.
The study’s lead author uses the game show Who Wants To Be a Millionaire? as an prime example of this kind of “metacognition,” or thinking about our own thinking:
“You might have the opportunity to ask the audience or phone a friend,” says Steve Fleming, a neuroscientist at University College London. But, he adds, “You need to know how sure you are about your own answer before you opt to use those lifelines.” [NPR]
Both are shades of the truth, actually. Here’s what the scientists actually found:
Robert Wilson and his colleagues have been tracking more than a thousand people as part of their long-term study, begun in the early 1990s. The patients were 65 or older and the scientists interviewed them every three years.
Participants indicated on a 5-point scale how often they participated in seven activities: viewing television, listening to radio; reading newspapers; reading magazines; reading books; playing games like cards or doing puzzles; and going to museums. (A rating of 5 meant a person did some of these activities about every day; 3 meant several times a month; 1 meant once a year or less) [LiveScience].
Finally, a big head comes in handy.
For a study out this week in Neurology, scientists looked at 270 Alzheimer’s patients from the Multi-Institutional Research in Alzheimer’s Genetic Epidemiology study (MIRAGE) and found that a larger head size was correlated with better-preserved cognitive and memory skills. The team, led by Robert Perneczky, argues that a bigger cranial circumference could mean a person has more “brain reserve,” offering some protection against the deterioration brought on by Alzheimer’s.
Finding this out took a lot more than just scanning the patients for cerebral atrophy and then wrapping a tape measure around their heads to gauge circumference:
They took blood to see which variant of the APOE gene was in their DNA (having one or two copies of the e4 version of APOE is thought to increase one’s risk of Alzheimer’s). They looked up the results of each patient’s most recent mini-mental state examination (MMSE) to measure cognitive function. They also took into account each patient’s age and ethnicity, how long they’d had Alzheimer’s and whether they had diabetes, hypertension or major depression [Los Angeles Times].
UPDATE: Some experts are questioning the validity of this study, and are suggesting that technical errors skewed the results. Full coverage here.
If you want to know how to get old, it’s best to ask the experts. That’s what Paola Sebastiani, a researcher at Boston University School of Public Health, did; She decided to look at the genes of 1,055 people, many who had already seen their 100th birthday.
As described in a paper published in Science today, Sebastiani’s team found that they could predict a person’s “exceptional longevity” with 77 percent accuracy.
The researchers looked at small variants called single-nucleotide polymorphisms (or SNPs) on the centenarians’ genomes; Sebastiani found she could use 150 SNPs to predict who would live to such exceptional ages.
Back and forth go the studies investigating whether cell phone uses increases the risk of brain cancer (the latest one to get major press, released last month, found nothing there). This week, though, new research has grabbed the headlines by declaring that our ubiquitous communication and time-wasting devices could actually provide a health benefit.
In a study set to come out today in the Journal of Alzheimer’s Disease (and funded in part by the National Institute on Aging), a group led by Gary Arendash argues that the radiation from cell phones that we’ve been worrying about could protect against Alzheimer’s Disease. But it’s far too soon to advise people to start medicating themselves by talking even longer on the phone.
Researchers at the Florida Alzheimer’s Disease Research Center arranged about 70 mouse cages in a circle around a central antenna that emitted electromagnetic waves typical of what would emanate from a phone pressed to a human head. They were exposed to the radiation for two hours a day over seven to nine months. About two dozen other mice served as controls [Los Angeles Times]. Arendash’s team used mice they had genetically engineered to develop the brain buildups and memory problems typical of Alzheimer’s when they got older. The team says that the memory problems of those mice exposed to the radiation began to disappear during the study. Not only that, but normal mice (that hadn’t been genetically engineered) also showed memory improvements after exposure.
This week, a eight-year double-blind study of the nutritional supplement ginkgo biloba finally reached the pages of the Journal of the American Medical Association. Many health food stores sell ginkgo supplements to people who are hoping to improve their wits and memory, and particularly to elderly people worried about cognitive decline and dementia. But the conclusion by lead researcher Steven DeKosky? Save your money.
In the GEM [Ginkgo Evaluation of Memory] study, participants aged 72-96 years with little or no cognitive impairment were recruited from four communities in the eastern United States and received either a twice-daily dose of 120-milligrams of extract of G biloba or an identical-looking placebo [AFP]. For the more than 3,000 study participants, researchers found no difference in age-related cognitive decline—including the incidence of dementia or Alzheimer’s—between ginkgo takers and placebo takers.
The researchers studied levels of amyloid beta — a protein that accumulates in the brain of people with Alzheimer’s — in mice genetically engineered to have a version of Alzheimer’s disease. Amyloid levels rose in the brain when the mice were awake, and fell when they slept. When the researchers prevented the mice from sleeping, it made matters worse [Reuters]. Sleep deprivation accelerated the formation of plaques made of amyloid beta, they found.
The study, published in Science, may lead to other studies that examine whether people with chronic sleep problems are more likely to develop Alzheimer’s. Says lead researcher Jae-Eun Kang: “The hope would be to show that treating sleep problems in humans is important not just for the immediate effect of having a normal life, but also for the long-term effect of having a healthier brain” [Bloomberg].
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A new study based on neurological data and brain specimens from a group of nuns, known as the Nun Study, confirms that language skills earlier in life are linked to Alzheimer’s disease risk in older age. But it also adds new, puzzling information to our knowledge about the disease: The brains of the women who did not have Alzheimer’s symptoms had larger brain cells, or neurons, but not necessarily fewer of the plaques and tangles characteristic of the disease.
To assess language skills early in life, researchers examined essays written by 14 women when they entered the convent, looking for the number of ideas expressed in every group of 10 words. A previous study linked grammatically complex writing skills to a decreased risk of dementia, and this study confirmed it: The essays written by women who maintained their memory scored 20 percent higher on language tests. “This is the second independent sample with the same result. We’re back to the metaphor of the brain as a computer and a muscle,” said [geriatric psychiatrist] Dr. Gary J. Kennedy…. “In volunteers who had no signs of Alzheimer’s but did have the plaques and tangles, the neurons were actually larger and more functional with more connections” [U.S. News and World Report].
Inserting a “pacemaker” into the brain to emit regular pulses of electricity and quell disordered neural activity may sound like a therapy of last resort, but if current experiments show beneficial results the brain surgery may one day be commonplace. But some scientists are cautioning that research on so-called deep brain stimulation may be pressing ahead too quickly, and warn that long-term effects of the surgery are not yet clear.
A growing number of psychiatric researchers are testing the method’s effectiveness on a host of psychiatric disorders. Until recently, deep brain stimulation was approved in the U.S. only to treat certain movement disorders, primarily those of Parkinson’s disease, for which it diminishes tremors and rigidity and improves mobility. To date, more than 60,000 patients worldwide have had the devices implanted [Los Angeles Times]. But now large clinical trials are in the works that will test the use of deep brain stimulation for obsessive compulsive disorder, epilepsy, and depression. Smaller experiments are beginning to assess the therapy’s effectiveness on a wide range of disorders including anorexia, drug addiction, obesity, traumatic brain injury, and Alzheimer’s.
Young adults with a genetic variant that increases their chance of developing Alzheimer’s later in life also have increased activity in the section of their brain devoted to memory, a new study has found. Researchers say the results suggest that the memory portion of the brain, the hippocampus, may eventually get worn out from a lifetime of overuse.
Researchers conducted fMRI brain scans of 36 volunteers, half of whom had at least one copy of the gene, known as APOE4. “We were surprised to see that even when the volunteers carrying APOE4 weren’t being asked to do anything, you could see the memory part of the brain working harder than it was in the other volunteers,” [study coauthor Christian] Beckmann said…. “Not all APOE4 carriers go on to develop Alzheimer’s, but it would make sense if in some people, the memory part of the brain effectively becomes exhausted from overwork and this contributes to the disease” [Reuters].
However, the researchers note that they’re far from proving this hypothesis, and say that it’s impossible to tell whether the extra activity contributes to Alzheimer’s symptoms later on or is just a sign of inefficient brain circuitry in the hippocampus [New Scientist].