Once again, scientists are trying to read your mind. Specifically, they are using fMRI (functional magnetic resonance imaging) to see what areas of the brain people use to process numbers, and even to determine what number a person just viewed.
Test subjects were shown images with either an amount of something—in this case a bunch of dots—or a numeral like 2, 4, or 6. Scientists suspected that our brains use overlapping areas to process quantities and their symbolic representations, however the findings suggest that people process the fundamental idea of a quantity differently from the way they process a symbol representing that quantity [Science News]. When a test subject looked at two dots and later at the number 2, different areas of the brain were activated, researchers report in Current Biology.
Here’s yet another reason to get a good night’s rest: Researchers have found a link between the lack of sleep and the development of Alzheimer’s in mice.
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].
A new experiment has shed light on how the monarch butterfly executes its impressive 2,000-mile migration every fall, and all it took was a lick of paint.
Researchers already knew that the butterflies use the sun to guide them to the exact same wintering spot in central Mexico. But because the sun is a moving target, changing position throughout the day, biologists have long speculated that in addition to having a “sun compass” in their brains, butterflies must use some kind of 24-hour clock to guide their migration [Wired.com]. In a new study, published in Science, researchers determined that the butterflies have a second circadian clock in their antennae, which sense light.
The researchers conducted the test by holding the butterfly wings gently and dipping their antennas in enamel paint. The ones with black paint were unable to orient to the south, they found, while butterflies whose antennas were coated with clear paint had no trouble navigating [AP]. This proved that the antennae had to be able to sense light for the butterflies’ navigation system to operate, and also showed that the butterflies weren’t navigating by scent, as both kinds of paint interfered with the insects‘ sense of smell.
Following up on today’s earlier post about alcohol and brain injuries, we bring you a study on alcohol and risk taking behavior. It seems obvious that drinking alcohol would lead to immediate risk taking, but does drinking as a teenager lead to risk taking behavior as an adult? Some researchers have suspected as much, but they haven’t been able to rule out the possibility that risk-prone people simply start drinking at an earlier age. So a research group chose an obvious course of action to test the idea—they got a bunch of rats drunk and let them gamble.
The researchers tested two groups of genetically identical rats, one group that was fed a normal diet and another that boozed it up. To get the rats drunk, the researchers borrowed the tried-and-true approach of frat boys everywhere—they fed them Jell-O shots. The rats went on a 20 day bender and were tested for risky behavior 3 weeks later, when they were adults, using a gambling task. The animals learned that pressing one lever produced small but certain rewards in the form of small sugar pellets and an adjacent lever yielded bigger rewards—more pellets—but paid off less frequently. The researchers rigged the game so that in some testing sessions choosing the certain reward was the best overall strategy, while in other sessions the “risky” lever yielded the greatest overall payoff [ScienceNOW Daily News].
People with alcohol in their system appear more likely to survive head injuries, according to a new study that has led to speculation that emergency rooms might someday keep a flask on hand to treat brain-injured patients.
Researchers analyzed a national trauma database containing 38,019 cases of moderate to severe head injuries where hospitals also tested the patients for alcohol. For every 100 patients with severe brain injuries who tested negative for alcohol and died, only 88 patients with alcohol in their bloodstream died, a statistically significant 12 percent difference, according to the study, which appears in the Sept. 21 issue of Archives of Surgery [The New York Times]. The boozing patients were also younger and suffered less severe injuries than their sober counterparts. The study is the largest to date examining alcohol’s effect on brain injury survival.
Sleep deprivation. Stress positions. Waterboarding. These interrogation techniques used by the Bush administration in the war on terror were explained, at the time, as harsh but necessary tactics that forced captives to give up names, plots, and other information. But a new look at the neurobiological effects of prolonged stress on the brain suggests that torture damages the memory, and therefore often produces bad intelligence.
Irish neuroscientist Shane O’Mara reviewed the scientific literature about the effect of stress on memory and brain function after reading descriptions of the CIA’s Bush-era interrogation methods. The methods were detailed in previously classified legal memos released in April. O’Mara did not examine or interview any of those interrogated by the CIA [AP].
His findings: “These techniques cause severe, repeated and prolonged stress, which compromises brain tissue supporting memory and executive function” [Wired.com]. The study, to be published in the journal Trends in Cognitive Sciences, took note of the effect of the stress hormone cortisol on the brain, as well as the fear-related hormone noradrenaline’s impact on memory and the ability to distinguish true from false.
Scientists recently used treadmill exercise, drugs, and electrical stimulation to train paralyzed rats to walk once again, demonstrating a way to possibly treat spinal injuries in humans, which at present are basically untreatable.
In a spinal injury, the neural circuits connecting the brain to the muscles that control walking become damaged or severed, leaving an individual paralyzed. In able-bodied people, these “walking circuits” spring into action when they receive a signal from the brain, but if the spinal cord is damaged, the message from the brain never arrives. When contact with the brain is lost, the circuits shut down [The Guardian]. In the study, published in Nature Neuroscience, researchers manipulated these circuits and produced movement that was “almost indistinguishable” from normal walking. See for yourself in the embedded video.
Some coma patients who appear to be completely unresponsive to the outside world are still capable of the most basic kind of learning, according to a small new study. Researchers found that both vegetative and “minimally conscious” patients were capable of a Pavlovian response, learning to associate a noise with a slightly unpleasant stimulus.
The researchers built on the work of 19th-century Russian psychologist Ivan Pavlov, who famously conditioned his dogs to salivate at the ring of a bell by associating the sound with the presentation of food. In this case, they sounded a tone, which was followed about 500 milliseconds later with a light puff of air to the eye [Scientific American]. At first the patients only responded after the puff of air by blinking or twitching or flinching. But after repeated trials, 15 of the 22 patients began to blink or flinch immediately after the tone sounded, before the puff of air. Electrodes by their eyes picked up the subtle muscle movements.
A person can witness an event in real life, see a doctored video of the same event, and then convince themselves that what they saw on the video is what actually happened, according to a recent study that casts doubt on the reliability of eyewitness testimony.
Psychologists set up an experiment where they filmed two people sitting side by side–one experimental subject and one researcher pretending to be a participant–playing a gambling game where they bet phony money on whether or not they could answer multiple choice questions correctly. They were told that the person with the most money at the end would win a prize.
Experiments conducted on squid brains in the early days of neuroscience created misunderstandings about the workings of the human brain that have persisted for 70 years, according to a new study. While the squid experiments did shed light on how messages are transmitted between brain cells with electrochemical signals (and led to a Nobel Prize for the experimenters), researchers are just now realizing that the results gave scientists a confused idea about the efficiency of neurons.
The story begins seventy years ago when a pair of British physiologists, Alan Hodgkin and Andrew Huxley, took the first stab at figuring out how neurons transmit electrical signals, known as action potentials. Because most neurons are small–in humans, a cubic millimeter of gray matter can contain 40,000 neurons–the duo turned to squid, which contain a giant axon, the long thin part of a neuron through which action potentials travel [ScienceNOW Daily News]. Those early experiments found that transmitting the action potential along the axon was a very inefficient process that used a great deal of energy, and neuroscientists ever since have assumed that mammal brains had the same inefficient wiring.
Researcher Henrik Alle, lead author of the new study published in Science, decided to reexamine the old assumptions. “I saw this old work,” says Alle. “I thought I cannot believe personally that nature would waste such energy.” Alle figured that nature would have made the process more efficient in mammals, whose brains send a huge number of messages [NPR News].
You may remember more than your conscious brain knows, according to a nifty new study that will soon be published in the journal Neuron. Researchers gave college students memory tests while closely monitoring both their eye movements and their brain activity, and found that certain patterns revealed that a student was retrieving the memory of the right answer–although his conscious brain often never got it.
In the experiment, researchers presented a long sequence of pictures of faces paired with an outdoor scene, and finally showed the subject one landscape photo along with three faces, asking him to pick out the face that had originally be paired with the landscape. Immediately, activity in the brain region called the hippocampus increased, followed 500 to 750 milliseconds later by eye movements directed toward one of the three faces. When the hippocampus was more active, the eyes lingered on the correct face. Less hippocampus activity occurred when the eyes dwelled on an incorrect face…. The results suggest that eye movements can reveal unconscious memories activated in the hippocampus [Science News]. This pattern stayed the same regardless of whether the subject ultimately settled on the right answer.
Kids suffering from attention deficit hyperactivity disorder (ADHD) may have altered brain chemistry that prevents them from experiencing motivation and rewards like other people, according to a new study published in the Journal of the American Medical Association. Lead researcher Nora Volkow suggests that faulty transmission of the brain chemical dopamine may be to blame for the difficulty people with ADHD experience trying to finish tasks that have no immediate payoff — the difference between doing homework, for instance, and playing a video game [CBC News].
The researchers used PET brain scans to determine how the brains of people with and without ADHD handled the neurotransmitter dopamine, a versatile chemical that is involved in regulating mood, attention, and learning. In particular they measured levels of two proteins – dopamine receptors and transporters – without which dopamine cannot function effectively to influence mood. ADHD patients had lower levels of both proteins in two areas of the brain known as the nucleus accumbens and midbrain. Both form part of the limbic system, responsible for the emotions, and sensations such as motivation and reward [BBC News].
It may not come as much of a surprise to dog-owners, but it seems that dogs and babies share similar logical abilities, as shown by a study published in Science.
Experimenters started out with a classic logic experiment, which goes like this: researchers hide a toy in location “A” multiple times while looking at a 10-month-old baby and talking to him (”Look, I have this nice ball!”). When asked to find the toy, the baby always goes to location “A.” The experimenter then hides the toy at location “B,” again while interacting with the baby. But this time, when asked to find the toy, the baby continues to search for it at location “A.” The findings hold, even when a team changes experimenters midtest. Researchers believe that infants make this error because they believe the adults have taught them something fundamental about the world (i.e., “Your toy will always be at location ‘A’”) [ScienceNow].
If you’re trying to get people to work together, carrots may prove more useful than sticks–that is, rewarding cooperation might motivate people more than punishing them, according to a study published in Science.
Test subjects played the “public goods game,” in which they have to decide whether or not to donate money to the group’s pot. The pot is multiplied and redistributed equally, regardless of who contributes and who doesn’t. When people play a pure version of the game, the temptation to freeload – reap the rewards without contributing anything – often leads to rapidly disintegrating cooperation [New Scientist]. But researchers found that when players were given the choice to either reward their fellow players for good behavior, or punish them for failing to donate, rewarding others yielded a larger payoff for the group as a whole. Groups that could reward each other earned much higher payoffs than those that could only punish, or those that could do neither [ScienceBlogs].
Pigeons alert their flockmates to impending danger not through vocalization, but by making a whistling sound with their wings as they take off in response to a threat, according to a study published in the journal Proceedings of the Royal Society B. Researchers say other birds may also have co-opted the basic mechanical sounds of flight for communication purposes.
Biologists were curious about how all the pigeons in a huge flock knew to launch themselves into the air at the same moment. Because the birds don’t use vocal calls to alert their peers, scientists hypothesized they convey the message using their wings. Researchers first recorded the sounds made by crested pigeons flying happily around a feeder, then sent in a decoy of a hawk, and recorded their flight from the faux predator. When the researchers later played the sound back for a flock of birds, they didn’t so much as twitch at the normal recording. But the rapid clap-clap-clap of the alarmed bird sent them fleeing. Similarly, when the volume or speed of the recording was manipulated, birds only reacted to emergency wing whistles [Discovery News]. Although it’s not yet known exactly how the birds make these sounds, the study’s results could do more than increase our understanding of bird communication. They could also help repel the pesky birds from places where they are annoying or even harmful, like public parks and airports.
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Once again, scientists are trying to read your mind. Specifically, they are using fMRI (functional magnetic resonance imaging) to see what areas of the brain people use to process numbers, and even to determine what number a person just viewed. 
Here’s yet another reason to get a good night’s rest: Researchers have found a link between the lack of 
A new experiment has shed light on how the monarch 
Following up on today’s earlier post about 
People with 
Sleep deprivation. Stress positions. Waterboarding. These interrogation techniques used by the Bush administration in the war on terror were explained, at the time, as harsh but necessary tactics that forced captives to give up names, plots, and other information. But a new look at the neurobiological effects of prolonged stress on the brain suggests that torture damages the memory, and therefore often produces bad intelligence.
Some coma patients who appear to be completely unresponsive to the outside world are still capable of the most basic kind of 
A person can witness an event in real life, 
Experiments conducted on squid brains in the early days of neuroscience created misunderstandings about the workings of the human brain that have persisted for 70 years, according to a new study. While the squid experiments did shed light on how messages are transmitted between brain cells with electrochemical signals (and led to a 
You may remember more than your conscious brain knows, according to a nifty new study that will soon be published in the journal 
Kids suffering from attention deficit hyperactivity disorder (
It may not come as much of a surprise to dog-owners, but it seems that dogs and babies share similar logical abilities, as shown by a 
If you’re trying to get people to work together, carrots may prove more useful than sticks–that is, rewarding cooperation might motivate people more than punishing them, according to a 
