One headline reads “Doing Puzzles ‘Could Speed Up Dementia.’” Another, “Brain Exercise Helps Stave Off Dementia.” They’re both about the same new study out in Neurology this week. So which is it?
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].
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If there’s a certain smell or sound that instantly brings back traumatic memories, it could be because those memories are stored—at least in part—in brain regions associated with the input of your senses, according to a study this week in Science.
Neuroscientist Benedetto Sacchetti went looking in rat brains for the neural connections between the senses and intense memories.
Each sense, including sound, smell and vision, has a primary and a secondary sensory cortex area in the brain. The primary cortex sends sensory information to the secondary cortex, which then connects to emotional and memory areas of the brain [Science News].
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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].
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Poke a snail with a stick and it remembers for a day. Poke a snail with a stick after you’ve given it methamphetamine and it remembers for much longer.
Getting gastropods hooked on meth perhaps sounds cruel, but Barbara Sorg and her team are among those scientists trying to figure out how the drug works in the brain to produce intense connections that feed the addiction cycle. In a study forthcoming in the Journal of Experimental Biology, the scientists show that, in snails at least, meth makes it hard to forget things that happened while on the drug.
Here’s the test: The snails Sorg studied can breathe two ways, through their skin underwater and also through a breathing tube they can deploy when they surface. The team kept two groups of snails—one on meth, one not—in separate tanks of shallow water. And if the snails tried to surface and breathe that way, the scientists would poke them.
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Don’t be deceived by the peaceful look of a newborn baby asleep in a crib–that little tyke may actually be hard at work, soaking up information about the world. A new study has found that newborns are capable of a rudimentary form of learning while they’re asleep, which may be an important process, considering that infants spend between 16 to 18 hours a day in the land of Nod.
Researchers recruited one- and two-day-old infants for the study, published in the Proceedings of the National Academy of Sciences. With each sleeping baby, the researchers played a musical tone and followed that by a puff of air to the eyes, a mild annoyance that caused the infant to automatically scrunch up its eyes. As this sequence of events was repeated, the sleeping babies learned to associate the air puff with the tone, and soon began to to tighten their eyelids as soon as they heard the musical note, even if the air puff didn’t follow. Electrodes stuck to their scalps also showed activity in the prefrontal cortex, which is involved in memory.
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A team of French scientists have proposed that when it comes to multi-tasking, our brains can handle only so much. In a new study, published in Science, scientists Sylvain Charron and Etienne Koechlin found that while the brain can easily divide its attention between two tasks, a third task will begin to slow it down–suggesting there is an upper limit to our multi-tasking abilities.
The scientists asked volunteers to do two complicated matching tasks simultaneously. With two tasks to deal with, the brain’s frontal lobes swung into action, working together to get the job done. The left side of the brain picked up one assignment while the right managed the other. But when scientists threw a third task into the mix, the brain began to fumble, with the volunteers making mistakes and slowing down, leading Koechlin to suggest that our frontal lobes “can’t maintain more than two tasks.”
To find out more about how the brain maxes out on multi-tasking and what this means for people who drink coffee and text while driving, head to Not Exactly Rocket Science’s for Ed Yong’s post: When multi-tasking, each half of the brain focuses on different goals.
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Image: Etienne Koechlin
Eleanor Maguire can’t read your mind. But she’s getting closer.
Two years ago the neuroscientist’s team used functional MRI scans of the brain to predict where in a virtual reality environment a person was “standing” just by looking at their brain activity. And now, in a study for Current Biology, she’s used fMRI scans, interpreted by a computer algorithm, to pick out the patterns of brain activity that indicate whether a person is remembering one movie versus another.
An fMRI scan measures the brain’s blood flow—associated with neuron activity—on the scale of voxels, three-dimensional “pixels” that each include roughly 10,000 neurons. The algorithm then interprets the changes voxel by voxel to learn the brain’s patterns of activity over time [ScienceNOW]. In this experiment, Maguire’s team showed their 10 participants three different movies. Each was short, only about seven seconds, but featured a different actress doing a different simple activity, like mailing a letter or drinking coffee. The scientists then asked the subjects remember the films while the team scanned their brains.
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Forgetting an umbrella or the location of a parking spot may be annoying, but scientists have suggested that for healthy brains to function well, they need to forget. By forgetting, scientists say, the brain makes space for new memories. In an intriguing breakthrough, researchers from the United States and China have identified the protein responsible for forgetting in fruit flies. By tweaking a protein called Rac, researchers were able to speed up and slow down the erasure of painful memories [New Scientist]. The findings were published in the journal Cell.
Scientists have been unable to pinpoint why people forget. Some have suggested that new memories are ephemeral and vanish over time, while others thought that interference caused earlier short-term memories to be overridden as new information comes in [Science Daily]. While both of these notions seem to suggest that forgetting is a passive mechanism, the new study suggests that forgetting is far more active, and that Rac works to inhibit the formation of more long-term memories.
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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.
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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.
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One year ago today, a brain-damaged man died peacefully at the age of 82, and neuroscientists the world over learned the identity of the man who was referred to in the textbooks only as “H.M.” Henry Gustav Molaison lost much of a brain structure called the hippocampus during an operation in the 1950s. The procedure was meant to stop his epileptic seizures. However, the hippocampus is critical to memory formation, so the surgery left Molaison unable to form new long-term memories [New Scientist]. By studying Molaison’s behavior over decades, researchers learned an enormous amount about memory formation.
Today, researchers at The Brain Observatory in San Diego are taking the next step in studying the workings of Molaison’s brain: They’re slicing it up. During Molaison’s life, he and his guardian agreed that his brain should be donated to science upon his death. So his brain was frozen, and beginning today it will be cut into about 2,600 very thin slices (think deli meat). Each slice will be photographed, and many will be studied microscopically to determine exactly which parts of Molaison’s brain were damaged in that long-ago operation. The slicing operation, which began about an hour ago, is being streamed live on the Internet, although it’s hardly a gripping action sequence (it looks more like scientists going about their business in a lab). In addition, the photos of the brain slices will soon be posted online for all the world to marvel at.
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Amid mounting evidence that sleep is key for your memory, researchers published a paper in the journal Science last week suggesting that playing specific sounds while a person sleeps—sounds connected to something that the person is trying to memorize—could help the memory sink in.
The researchers taught people to move 50 pictures to their correct locations on a computer screen. Each picture was accompanied by a related sound — meow for a cat, whirring for a helicopter, for example [The New York Times]. Next the test subjects lay down for a nap, and while they slept the researchers played sounds relating to half the objects. When the subjects woke up, scientists tested them on how well they remembered where each object went. Participants didn’t know they’d been subjected to the sounds while they napped, but they fared better at placing the objects for which they heard sounds in their sleep than those they didn’t.
Lead researcher Ken Paller explains: “While asleep, people might process anything that happened during the day — what they ate for breakfast, television shows they watched, anything…. But we decided which memories our volunteers would activate, guiding them to rehearse some of the locations they had learned an hour earlier” [U.S. News & World Report].
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Scientists who have been investigating the link between professional football and severe brain damage have a troubling new piece of evidence: The brain of a deceased man who stopped playing football after college also showed the distinctive signs of damage. The man, the former Western Illinois wide receiver Mike Borich, died at 42 of a drug overdose in February after a downward spiral of depression and substance abuse that is generally associated with the type of tissue damage found in his brain [The New York Times].
The findings suggest that the damage isn’t only associated with professional football players who have played at the highest level of competition for years, but might be a fundamental byproduct of the sport itself. The cumulative effect of the many blows to the head that many football players experience may simply be too much for the brain to handle, researchers say.
Several neuroscientists have been investigating football players with a condition called chronic traumatic encephalopathy (C.T.E.). Scientific progress is slow because the condition can only be diagnosed after death, when the brains donated by players can be sliced, stained, and examined for protein deposits and fibrous tangles. So far, researchers have identified C.T.E. in eight NFL players who died between the ages of 36 and 52–many of whom had extreme emotional problems in their last years. It has been found in every player of those ages examined by the two groups doing such research [The New York Times].
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Researchers have found a pharmaceutical way to clear some of the cognitive fog that results from a sleepless night. In a new study using lab mice, researchers corrected the memory problems in sleep-deprived mice through a drug that suppressed levels of a certain enzyme in a brain region called the hippocampus, which plays an important role in memory and learning.
The study, published in Nature, helps tease out the specific effects of sleep deprivation on the brain. Says lead researcher Christopher Vecsey: “One of the main problems is that sleep deprivation does a lot of things to the brain, and it’s easy to get caught in a mish-mash of different effects” [Nature News].
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It sounds like a scene from an insect version of Total Recall: Using genetically engineered fruit flies and laser beams, researchers have found a way to embed false, fearful memories in the flies.
Researchers first tested normal flies in a chamber where a jets of air on either side brought two different odors into the container. The researchers delivered an electric shock each time a fly strayed into a particular odour stream, which taught the flies to prefer the other one: the flies learned to move in the direction of the shock-related odour 30 per cent less often [New Scientist].
Next, the researchers created a strain of genetically engineered flies with certain neurons that would be activated by a laser blast. Lead researcher Gero Miesenböck explains that with this technique, called optogenetics, researchers can use light to activate particular cell types that have been genetically engineered to express a light-responsive protein. When laser pulses hit the brain, cells expressing the light-sensitive protein activate. “It’s like sending a radio signal to a city but only those houses with a radios set to the right frequency will get the signal,” says Miesenböck [Nature News].
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