80beats » Mind & Brain

In Flies, a Prion-Like Protein Helps Maintain Long-Term Memories

Sarah Zhang — Wed, 08 Feb 2012 13:08:56 +0000

What’s the News: When prions or amyloids make the news, it’s usually because they cause mad cow disease or Alzheimer’s—prions, after all, cause any proteins they touch to become as misfolded as they are, and amyloids, which are large clumps of wadded-together proteins, can jam the workings of cells.

But a new study in Cell suggests that a prion-like protein that forms amyloids has a normal, vital function in the brain. Far from being a memory destroyer, this protein, called CPEB, is necessary for long-term memory in fruit flies.

How the Heck:

To see where the protein resides in the brain, the researchers added a fluorescent tag to the fruit fly version of CPEB, which is called Orb2A. They observed that Orb2A formed amyloids at synapses, the junctions between neurons—a promising sign that it could be involved in memory. To see whether Orb2A was actually necessary for memory, the researchers created fly mutants with a defective version of Orb2A. A single amino acid was changed, but that was enough to prevent the formation of amyloids. It was also enough to disrupt the flies’ long-term memory, the team found. As a test of memory, flies had been ...

Alzheimer’s Spreads Like a Virus From Neuron to Neuron, Studies Show

Valerie Ross — Fri, 03 Feb 2012 13:30:21 +0000

A protein tangle in an Alzheimer’s-afflicted neuron

Exactly how Alzheimer’s disease proliferates through the brain, overtaking one region after another, has eluded scientists. As the disease progresses, tau—a malformed protein that forms snarls and tangles inside neurons—shows up in more and more brain areas. Researchers have wondered whether tau, and the disease, are working their way out from a single area of origin or mounting numerous, distinct attacks on vulnerable parts of the brain. Two new studies in mice provide strong support for the first idea: Tau see ms to pass from affected cells to their neighbors, spreading much the same way a virus or bacteria infection would.

The studies—one recently published in PLoS ONE, the other forthcoming in Neuron—used mice genetically engineered to produce abnormal human tau protein in the entorhinal cortex, the tiny bit of brain tissue where Alzheimer’s first appears in most patients. Since those cells, but not others, were equipped to produce human tau, any tau that showed up elsewhere in the brain could be traced back to the entorhinal cortex. The researchers watched and waited, and found that the tau proteins spread through neural circuits out ...

Does a Chinese Boy Really Have “Cat Eyes” That See in the Dark?

Sarah Zhang — Thu, 02 Feb 2012 23:23:09 +0000

The strangest thing about this Chinese boy’s light blue eyes is not their color. It’s the purported fact that he can see in the dark. His eyes are just like cat eyes, glowing blue-green when you shine a light in them, says this clip from China’s state-run English TV channel. The boy can catch crickets in the dark without a flashlight and even completes a writing test in a pitch-black stairwell. True, or too good to be?

Natalie Wolchover at Life’s Little Mysteries has rounded up some experts and their collective reaction seems to be, “Hmm…” (It doesn’t help that this video has been posted on YouTube under the name, “Alien Hybrid or Starchild Discovered in China? 2012.”) One possibility they consider is whether the boy has a mutation that produced something like a tapetum lucidum, an extra layer of tissue that helps cats see in the dark. James Reynolds, a pediatric ophthalmologist at State University of New York in Buffalo, puts a stop to that idea:

[T]here is no single genetic mutation that could produce a fully formed and functioning tapetum lucidum, Reynolds explained; such an ability would require multiple mutations, which wouldn’t occur all at once. Evolution happens incrementally, ...

Research on Quebec’s Rare Brain Disease Could Help Unravel the Common Ones

Valerie Ross — Tue, 17 Jan 2012 19:56:15 +0000

Artist’s rendering of a mitochondrian, the energy-producing
cellular structure affected by ARSACS

Scientists have pinpointed the cause of a rare, fatal neurodegenerative disorder called ARSACS, or autosomal recessive spastic ataxia of Charlevoix-Saguenay. The disease is due to defects in neuron’s mitochondria, the bit of biological machinery that generates energy for the cell—a structure known to be affected in Parkinson’s, Alzheimer’s, and other neurological diseases, as well.

ARSACS was first observed in the descendants of a small group of 17th century French settlers who made their homes near the Charlevoix and Saguenay rivers in what is now Quebec, and has since been seen worldwide. But its incidence remains unusually high in that particular French Canadian community, with 1 in 1,500 to 2,000 people developing ARSACS and 1 in 23 people unaffected genetic carriers of the disease.

The first symptoms of ARSACS appear in early childhood, often as a two- or three-year-old learns to walk, a skill that—because t he disease primarily affects the cerebellum, the brain’s motor control center—those suffering from ARSACS never master. As the disease progresses, it leads to muscle weakness, slurred speech, and difficulty coordinating or controlling movement. People with ARSACS ...

The Linguistic Phenomenon Du Jour: Vocal Fry

Veronique Greenwood — Tue, 13 Dec 2011 18:26:04 +0000

What’s the News: Rarely has a humble little sound aroused such interest as in the last few days, as a paper about a phenomenon called vocal fry, a creak in someone’s voice as they speak, has been propelled to web prominence. Though many outlets got some basic facts wrong—the new study doesn’t actually show that fry has become more common among young women, just that it was common in the small group surveyed—all recognized the opportunity to launch into something we wish we knew more about: why we make funny sounds when we talk.

How the Heck:

Vocal fry is a low, rumbling creak that, in English speakers, seems to appear mostly at the ends of sentences and has been captured in voice recordings going back to the early part of last century. Below is a clip (start watching at 34 seconds) with Mae West showing vocal fry on the “me” in “Why don’t you come up sometime, see me,” identified by the linguistics wonks at Language Log. Basically, it’s the opposite end of the spectrum from falsetto.

The researchers at Long Island University, Brookville, have been wondering how widespread the vocal ...

A Sleeping Pill Awakens Some Minimally Conscious Patients

Valerie Ross — Mon, 05 Dec 2011 20:32:43 +0000

Doctors long believed that patients who remained in a coma weeks or more after a brain injury would never regain consciousness. But recent research has shown that consciousness isn’t a binary, awake-or-not state; it’s a spectrum. While some brain injury patients are in a vegetative state, without any conscious awareness, others are in what’s called a minimally conscious state, still partially aware of—and at times even able to respond to—their surroundings. From the outside, it can be difficult to tell the two apart, though new methods, such as EEGs that pick up on subtle differences in brain waves, are starting to help clinicians gauge a patient’s level of consciousness.

From these hinterlands of consciousness comes another astounding—and mysterious—discovery: Ambien, the prescription sleep medication, and zolpidem, the drug’s generic form, can help some minimally conscious patients wake up. Jeneen Interlandi delves deep into this seemingly paradoxical treatment in the New York Times magazine:

The first report of a zolpidem awakening came from South Africa, in 1999. A patient named Louis Viljoen, who, three years before, was declared vegetative after he was hit by a truck, had taken to clawing at ...

New Tool Detects Photoshop Shenanigans in Fashion Photos

Veronique Greenwood — Tue, 29 Nov 2011 19:28:57 +0000

An image analyzed by the researchers, before retouching, after retouching, with an overlay that shows the strongest retouching in red, and with two facial overlays showing other measures of retouching.

What’s the News: It’s not news that in the age of Photoshop, celebrities and models in magazines have started to look like perfect aliens crash-landed among we ugly Earthlings. But though sometimes it’s obvious when a photo editor has gone too far (witness the Ralph Lauren her-head’s-bigger-than-her-pelvis debacle), the gap between what real people look like and what magazines and other media regularly show has grown distressingly wide without most people consciously noticing it, creating a sea of misinformation that may contribute to body-image disorders.

An analytical tool developed by Dartmouth scientists, though, picks up and quantifies those alterations, potentially providing a useful metric for policymakers looking to set boundaries on how much limb-stretching, torso-trimming, face-smoothing alteration is appropriate.

How the Heck:

The tool rates altered images on the basis of geometric change, like stretching and shrinking, and photometric changes, like airbrushing and heightened colors. To test their system, the researchers had 390 volunteers from Amazon’s Mechanical Turk service analyze 468 photos before and after retouching, most ...

Ever Enter a Room & Forget Why You Went There? Blame The Doorway.

Douglas Main — Tue, 22 Nov 2011 16:35:21 +0000

New research suggests the mere act of walking through a doorway helps people forget, which could explain many millions of confusing moments that happen each day around the world. A study published recently in The Quarterly Journal of Experimental Psychology found that participants who walked through doorways in a virtual reality environment were significantly more likely to forget memories formed in another room, compared with those who traveled the same distance but crossed no thresholds.

Notre Dame University researcher Gabriel Radvansky says doorways serve as a type of “event boundary” that the brain uses to separate and store memories. When you enter a new room, your brain updates its understanding of what’s going on in the new environment, which takes some mental effort. This parsing of memory, albeit subtle, leaves the information encoded in the other room (i.e. “Now I’m going to my room to fetch some knickers”) less available in your new location.

Recognizing this tendency could help you avoid future lapses. Or you could take Radvansky’s advice, as (jokingly—I think) told to Postmedia News: ”Doorways are bad. Avoid them at all costs.”

Reference: Gabriel A. Radvansky, Sabine A. Krawietz ...

Hyperactive Visual Cortex Neurons May Cause Orange “O”s and Purple “P”s

Valerie Ross — Fri, 18 Nov 2011 19:36:02 +0000

The colors that letters and numbers appear to a synesthete

What’s the News: For most of us, our senses stay relatively separate: that is, we hear what we hear and see what we see. People with synesthesia, however, actually see words as colors, taste a particular flavor when they hear a familiar song, or experience other strong, automatic linkages between senses. The neurological underpinnings of the condition—how the brain connects two usually distinct senses—have remained a mystery. But researchers have now found a possible cause, they reported yesterday: neurons in the area responsible for the second sensation, such as the color that goes with the word, may be unusually excitable.

How the Heck:

Six people with grapheme-color synesthesia—the most common form of the condition, in which people associate letters and numbers with colors—and six non-synesthete controls participated in the study. The researchers applied transcranial magnetic stimulation, a weak magnetic field that travels through the skull and changes neuronal activity, to each volunteer’s primary visual cortex, a part of the brain that processes what we see. The people with synesthesia needed only a third as much stimulation as the other volunteers before they started ...

What Is Synthetic Pot, and Why’s It Causing Heart Attacks in Teenagers?

Douglas Main — Fri, 18 Nov 2011 13:44:13 +0000

What’s The News: Three 16-year-old teenage boys in Texas had heart attacks shortly after smoking a product called k2, or Spice, according to a study published this month in the journal Pediatrics. The report highlights a growing public health problem: the increased availability and use of synthetic cannabinoids, which when smoked mimic the effects of marijuana but typically can’t be detected in drug tests. While the U.S. Drug Enforcement Agency secured an emergency, one-year ban of five synthetic cannabinoids in March of this year, most of the hundreds of such chemicals remain basically legal, widely available, little understood, and potentially harmful.

“Fake Pot” and Synthetic Cannabinoids:

“Fake pot” includes any of a number of products (with names like K2, Spice, Blaze, Red X Dawn) that are increasingly popular among young Americans. They usually contain herbs laced with various synthetic cannabinoids, and often marketed as incense. Synthetic cannabinoids function similarly to marijuana’s prime ingredient, tetrahydrocannabinol (or THC), which causes most of the plant’s well-known effects by partially activating cannabinoid receptors in the brain. (Described in some detail in an earlier post of mine here.) Most of these chemicals bind much more ...

Despite Debilitating Memory Loss, an Amnesic Cellist Learns and Remembers Music

Valerie Ross — Mon, 14 Nov 2011 18:03:26 +0000

A 68-year-old concert cellist suffering from severe amnesia can still learn new music, researchers reported [pdf] at the Society for Neuroscience conference this weekend. In 2005, the cellist suffered a bout of herpes encephalitis, a dangerous infection that causes inflammation in the brain. His medial temporal lobes, brain structures important in remembering facts and events—what scientists call explicit memory—were destroyed. As a result, the cellist, referred to by the initials PM, was left with both retrograde amnesia (meaning he couldn’t remember events from his past) and anterograde amnesia (meaning he couldn’t form new memories).

And yet, as Ian Sample details in the Guardian, PM could learn and recall music:

Doctors made their discovery when they tested PM’s ability to recall musical information and found he could identify the scales, rhythms and intervals of pieces they played him. The man went on to score normally on a standard test for musical memory.

But it was later tests that surprised doctors most, when the cellist showed he could learn new pieces of music, even though he failed to remember simple information, such as the layout of his flat, who his ...

Group-Think and Gods: Why Penn State Students Rioted for Joe Paterno

Veronique Greenwood — Fri, 11 Nov 2011 16:47:13 +0000

Two days ago, Penn State students rioted in support of the university’s longtime football coach, Joe Paterno, who had just been fired. The reason? When he learned in 2002 that his then-assistant Jerry Sandusky had been seen sexually assaulting a child in the football team’s showers, according to the grand jury indictment of Sandusky [pdf], he directed the witness to go to the athletic director, and the police were never contacted. Sandusky has now been charged with sexually abusing eight boys over a 15-year span, and Paterno, who has won more games than any other coach in college football, has lost his job.

And yet, to the shock of many around the country who found the grand jury’s report extremely disturbing, students still stood up for him. Karen Schrock at Scientific American delves into the social science of group-think and explains why, when you’re part of a group, especially one defined by a charismatic individual, it changes the way you think:

According to psychological theory, every person has a social identity, which depends on being a member of various groups. “The social groups you belong to become a part of the very essence of who you feel you are,” ...

New Neurons From Stem Cells Get Us Closer to Treating Parkinson’s

Valerie Ross — Tue, 08 Nov 2011 21:46:56 +0000

Neurons damaged by Parkinson’s disease

What’s the News: Scientists have reversed Parkinson’s disease-like brain damage and motor problems in mice and rats using neurons grown from human embryonic stem cells. The new technique, described online in Nature earlier this week, brings scientists closer to similar treatments for people with Parkinson’s.

How the Heck:

The treatment started with stem cells from human embryos, cells with the ability to develop into any type of tissue in the body. By bathing these cells in a chemical mix that mimics what neurons experience during normal development, the research team turned the stem cells into the particular type of cell that Parkinson’s slowly kills off: neurons that produce the neurotransmitter dopamine. The researchers then injected over 100,000 of these newly grown neurons into the brains of mice that had a rodent equivalent of Parkinson’s disease: damaged dopamine-producing cells and the resulting difficulties controlling muscle movement. Over the course of three to five months, the transplanted neurons thrived, connecting with surrounding brain cells, and the mice’s motor function greatly improved. When the team repeated the experiment in rats, the result was the same: A few months later, the stem cell-derived neurons had ...

Study Links Fetal Bisphenol A Exposure to Behavioral Problems in Girls

Douglas Main — Wed, 26 Oct 2011 17:06:35 +0000

A study published this week in the journal Pediatrics found a link between levels of bisphenol-A in pregnant moms and behavioral problems such as anxiety and hyperactivity in their daughters at age 3. No such effects were seen in boys. BPA has estrogen-like activity and can lead to developmental and behavioral problems in animals—but whether or not it does the same in humans, and at what dosages, is a subject of considerable debate. This study won’t settle the debate but highlights the need to answer some basic questions about BPA that remain surprisingly unclear.

What’s the Context:

Bisphenol-A is used in many types of plastics like polycarbonate, linings of metal cans, and in receipts (even some labeled “BPA-free”). It shows up in the urine of the vast majority of Americans. Since BPA mimics estrogen in the body, it may effect mental and sexual development, especially if it is present very early in life. For this reason it has been explicitly banned from being used in baby bottles in several European countries, and BPA manufacturers say they don’t sell the chemical to makers of baby bottles. Animal studies show fetal or early-life ...

Army Looks Into Treating PTSD with Dream Manipulation

Veronique Greenwood — Fri, 21 Oct 2011 19:27:33 +0000

What’s the News: Recurring nightmares can cast a pall over anyone’s waking life, and for soldiers with post-traumatic stress disorder, they can also contribute to panic attacks, flashbacks, and violent behavior. Can soothing, dream-like experiences in a virtual world, entered immediately after a nightmare runs its course, tame those bad dreams? It seems like a kind of real-life inception, but it’s not as far fetched as you’d think: the Army is investigating just such a treatment, Dawn Lim at Wired’s Danger Room reports.

How the Heck:

The idea builds on existing treatments used for PTSD, including image rehearsal therapy, in which therapists work with patients to identify triggers and devise ways to defuse them, and biofeedback, in which patients watch real-time data on their stress levels on a computer screen and observe how different relaxation techniques help bring the levels to normal. In the proposed treatment, a soldier waking up from a PTSD nightmare can put on 3D vision goggles and enter an animated world populated with comforting sights. The world will be one he’s built himself in visits to his clinic, where, using biofeedback to track his response, he has trained ...

For Kids Under Two, Steer Clear of Screen Time, Pediatricians Say

Valerie Ross — Wed, 19 Oct 2011 15:15:17 +0000

Parents should strictly limit how much children under two years old watch television or videos, says the American Academy of Pediatrics in a new policy statement, since TV time not only doesn’t seem to benefit babies, it may come with developmental drawbacks. (Activities like computer and touchscreen games, where the babies interact with what’s happening on the screen rather than passively watch it, aren’t included in the statement.) The academy issued a similar statement in 1999, discouraging screen time for kids less than 24 months old—and in the intervening decade, there’s been more research to back up that recommendation.

Time spent watching TV is, scientists point out, time away from the independent play known to be important for healthy cognitive development, and increased screen time is linked to developmental delays. But even if babies aren’t simply sitting and watching a video, a TV or movie playing in the background—as one researcher calls it, “secondhand TV”—could have downsides. Not only does it distract babies, who look up at a video on average three times a minute even if they’re otherwise occupied by play, it distracts parents, as well, leading them to talk to their little ...

Unlike the Rest of Us, Autistics Don’t Act Like Angels When Someone’s Watching

Valerie Ross — Mon, 17 Oct 2011 16:10:37 +0000

We want others to think well of us—so if we know someone’s watching, most of us tend to behave a little better. People with autism spectrum disorders, however, don’t, a new study in the Proceedings of the National Academy of Sciences found. Since most people, psychologists think, clean up their acts out of concern for their social reputation, the new study bolsters the idea that people with autism and related conditions don’t take into account, or perhaps fully understand, what others think of them.

In the study, both high-functioning people with autism spectrum disorders and healthy controls matched for age, sex, and IQ did a simple charitable giving task: They were shown a variety of ways money could be divvied up between themselves and the charitable organization UNICEF, and given the option to OK the split or keep the whole sum for themselves. (To make this more than a thought experiment, the experimenters picked one of the trials at random and followed through on the participant’s answer.) Both groups gave about the same to charity while alone. But when an experimenter watched some of the trials, the control group ...

Do Neutering and Spaying Cause Depression in Pets? No Word Yet, But an Interesting Question

Veronique Greenwood — Mon, 10 Oct 2011 17:17:08 +0000

Hormones are major mood-regulators, as anyone who has been cranky before a period or had their reproductive organs removed for medical reasons can tell you. In fact, depression is a common side effect of such surgeries in humans. But does that extend to some of the most regularly de-hormoned animals out there—our pets? That’s the thought-provoking thesis of a recent Slate piece, and while there’s been no systematic research on how such surgeries affect cats and dogs, a smattering of research has suggested that having your supply of hormones eliminated does affect the mood of mice and primates, free of the confounding influences one finds in humans. Madeleine Johnson of Slate describes one set of experiments:

[Researchers in Japan] reasoned these snow monkeys could model mood changes due to ovariectomy without confounding variables like the social stigma of barrenness that might affect women. The center picked 10 females of equivalent rank in the dominance hierarchies and removed the ovaries and uterus from five of them. The other five had their “tubes tied,” so were sterile but still had intact ovaries. Since the monkeys wouldn’t understand the biological ramifications of surgery, and would have similar social lives, ...

A Fold in the Brain is Linked to Keeping Reality and Imagination Separate, Study Finds

Valerie Ross — Fri, 07 Oct 2011 17:02:34 +0000

What’s the News: One of memory’s big jobs is to keep straight what actually happened versus what we imagined: whether we said something out loud or to ourselves, whether we locked the door behind us or just thought about locking the door. That ability, a new study found, is linked to the presence of a small fold in the front of the brain, which some people have and others don’t—a finding that could help researchers better understand not only healthy memory, but disorders like schizophrenia in which the line between the real and the imagined is blurred.

Scans of a brain with a distinctive paracingulate sulcus (left, marked by arrow) and without one (right)

How the Heck:

The researchers looked at MRI brain scans of a large group of healthy adults. In particular, they were looking for the paracingulate sulcus (PCS), a fold near the front of the brain. There’s a lot of variability in the PCS: some people have quite distinctive folds, others have barely any. It’s in a part of the brain known to be important in keeping track of reality, which is why the researchers chose to study it. ...

The Brain’s Medicine: Natural Marijuana-Like Chemicals Play Important Role in Placebo Effect

Douglas Main — Fri, 07 Oct 2011 16:03:18 +0000

Placebos are inactive treatments that shouldn’t, in some sense, have a real effect. And yet they often do. But the chemical basis of the placebo effect, despite its enormous importance, is still largely a mystery. A study published this week in Nature Medicine shows that cannabinoid receptors are involved in the placebo response to pain, which hasn’t been demonstrated before. The finding implies that the brain’s own endocannabinoids can fight pain, and actually do it via the same pathway as several compounds in the cannabis plant.

What’s the Context:

For most drugs and treatments to be approved today, they must be favorably compared to ineffective placebos to prove that the therapeutics actually work. (This comparison is not simple, and whether certain drugs—like many antidepressants—are actually better than placebos is a matter of considerable debate.) The placebo effect has a impressive ability to confound expectations. For example, in a 1999 study researchers gave participants an inert substance but said it was a stimulant. The patients became stimulated and tense. Stranger still, they gave people a muscle relaxant, also calling it a stimulant. The patients still tensed up. Much of what we know ...

Can Brain Scans Detect Pedophiles?

Veronique Greenwood — Wed, 05 Oct 2011 19:45:29 +0000

What’s the News: A new study suggests that watching brain activity when subjects are shown images of naked children can identify which are pedophiles. But what does this really mean in practical terms?

How the Heck:

24 self-identified pedophiles, from a clinic that offers anonymous treatment, and 32 male controls were shown pictures of naked men, women, and children. Blogger Neuroskeptic, who brought this study to the web’s attention, notes in an aside that getting that past a university ethics board is quite a coup. Using fMRI, the researchers recorded their brains’ responses and found that by comparing an individual’s brain to the average of the pedophiles and the average of the controls, they could assign them to the correct group more than 90% of the time. Their handling of the statistics avoids the most obvious pitfalls: they used an analyses technique called leave-one-out cross-validation to avoid comparing a given scan to an average that includes it, a common error in neuro studies. When they plotted how the neural scans lined up along the age and sex axes (see image above), the pedophile and control scans formed two clear, separate clusters.

What’s the Context:

First, a caveat: the team wasn’t ...

Drug in Magic Mushrooms Linked to Long-Lasting Personality Change…for the Better

Douglas Main — Mon, 03 Oct 2011 16:53:22 +0000

A recent study found that most people treated with a single high dose of psilocybin, the active ingredient in psychoactive mushrooms, showed a long-lasting change in personality—namely, an increase in openness. One of five broad measures of temperament used by psychologists, this quality is generally defined as openness to new ideas or experiences, awareness of feelings in the self and others, and is strongly tied to creativity and aesthetic appreciation. This is one of the first studies to link a single treatment with a drug in a laboratory setting to a long-lasting change in personality.

What’s the background:

The present study is an analysis of the results from two previous trials, published in 2006 and 2011. These showed that lab-administered psilocybin was linked to long-lasting improvements in study participant’s relationships, mood and general well-being, as reported by study participants and corroborated by their family members/friends. Researchers divided the 52 participants into two groups: those who had a “complete mystical experience,” and those who did not. Although it might seem hard to believe, given the vagaries of spiritual experience, psychologists have a relatively well-defined and established definition ...

How Did Researchers Manage to Read Movie Clips From the Brain?

Valerie Ross — Wed, 28 Sep 2011 18:06:50 +0000

What’s the news: In a study published last week, researchers showed they could reconstruct video clips by watching viewers’ brain activity. The video of the study’s results, below, is pretty amazing, showing the original clips and their reconstructions side by side. How does it work, and does it mean mind-reading is on its way in?

How to Read Movies From the Brain, in 4 Easy Steps:

1) Build the Translator. The researchers first had three people watch hours of movie trailers, tracking bloodflow in their brains—which is linked to what the neurons are up to, as active neurons use more oxygen from the bloodstream—with an fMRI scan. (All three subjects were part of the research team; over the course of the study, they had to be in the scanner for a looong time.) The team focused on brain activity in a portion of each person’s visual cortex, compiling information about how 4,000 different spots in the the visual cortex responded to various simple features of a movie clip. “For each point in the brain we measured, we built a dictionary that told us what oriented lines and motions and textures in the original image actually caused brain activity,” says Jack Gallant, the UC Berkeley neuroscientist ...

Marijuana for PTSD? That’s Leaving Out a Lot of Steps

Douglas Main — Wed, 28 Sep 2011 12:07:19 +0000

When rats were injected with a chemical similar to marijuana’s main ingredient, THC, shortly after a undergoing a severely stressful event, they showed a significant reduction in symptoms like those seen in people with post-traumatic stress disorder. The study tested a synthetic cannabinoid called WIN 55,212-2, which was injected directly into the animals’ amygdala, a brain region involved in the regulation of emotions like fear and anxiety. Timing was important. Rats given the drug two and 24 hours after the stressor—being forced to swim for 15 minutes—appeared less “traumatized” when tested a week later, compared with those given the drug 48 hours later or given no drug at all. While the study adds to the already large and complex pile of evidence that the cannabinoid system has a vital role in regulating emotions like anxiety, it’s far from proving that cannabinoids will be useful for treating PTSD in humans.

Unfortunately, virtually every story covering the study got it wrong by suggesting just that (e.g., “Marijuana blocks post-traumatic stress?” “Marijuana blocks PTSD symptoms in rats.”). And many, if not most stories, confused the synthetic THC mimic studied with THC or ...

Coffee May Help Ward Off Depression in Women, Study Finds

Douglas Main — Tue, 27 Sep 2011 17:38:03 +0000

A couple cups of coffee a day may help keep the blues away. A large epidemiological study of 50,000 women published yesterday in the Archives of Internal Medicine found that subjects who drink two or more cups of coffee on a daily basis were slightly less likely to be diagnosed with depression over a 10-year span compared to their less-caffeinated peers. Women who drank two to three cups of coffee were 15 percent less likely to be treated for the blues; those who drank four or more had a 20 percent lower risk.

The researchers point out that this was an observational study, so no cause-and-effect relationship can be established. It is possible, for example, that women who are more sensitive to the stimulant—and therefore drink less coffee—are more likely to become depressed. But the study is the largest of its kind to date and suggests coffee could help treat or ward off depression; at the very least, further research is warranted. The results add to the growing body of evidence that moderate daily ingestion of coffee is relatively healthy; it doesn’t seem to cause in increase in cardiovascular disease and may be ...

Brain Scans Suggest a New, Objective Way to Measure Pain

Valerie Ross — Thu, 22 Sep 2011 17:27:08 +0000

What’s the News: The best way doctors have to find out how much pain a patient’s in is to ask—but that approach can fall short when someone’s unable to speak, exaggerating or downplaying their condition, or just plain unsure how to rate their pain on a 10-point scale. Because of these problems with self-reporting, scientists have long been looking for an objective, physiological measure to quantify pain. A recent brain scanning study, in which the researchers could pick out painful experiences based on neural activity, brings that goal closer.

How the Heck:

The researchers gave each of 24 participants an fMRI scan, which measures blood flow in the brain. They tracked the participants’ brain activity as a small portion of their forearm was exposed to heat, which was either painful (quite hot) or not painful (pleasantly warm). A computer algorithm then analyzed the data for patterns, looking for types of brain activity that occurred in response to painful or not painful heat. The team next had 16 other people do the same thing, getting their brains scanned while their arms were exposed to various levels of heat. This time, the ...

Overestimating Your Own Abilities May Be an Evolutionary Boost

Valerie Ross — Tue, 20 Sep 2011 18:16:25 +0000

What’s the News: We may strive for humility, but we benefit from a little hubris, too, according to a study published last week in Nature. Overconfidence in your abilities can help you triumph in competitions you might not have won otherwise, the study found, and can impart an evolutionary advantage when the potential payoff is high compared to the cost of conflict.

How the Heck:

To investigate the effects of overconfidence, the researchers set up a game theory-based computer model. In this model, two individuals could each “decide” (through computer algorithms) whether or not to lay claim to a desired resource. If they both claimed it, the stronger individual won the resource, but both individuals incurred a small cost, the toll of competition. If only one individual decided to go after the resource, that individual got the prize without incurring a cost from conflict; if neither did, neither got it. Each competitor decided whether or not to claim the resource based on what they knew of their abilities compared to their opponents’. But, as is usually the case in real life, the individuals didn’t have a complete, unbiased view of the ...

Tiny Head-Mounted Microscope Rides Along As Mice Go About Their Business

Valerie Ross — Thu, 15 Sep 2011 16:49:17 +0000

What’s the News: A new thumbnail-sized microscope will give researchers a way to see what’s happening in the brain of a mouse as it moves around and goes about its business. The microscope, described earlier this week in Nature Methods, weighs less than 2 grams—little enough that it can be fitted atop a rodent’s head—and tracks the activity of up to 200 brain cells.

What’s the Context:

To watch a living brain in action, researchers usually have to make sure the animal that brain belongs to is keeping very still, be it a human in an MRI machine or a mouse under a benchtop microscope. That’s not such a problem for researchers studying, say, vision or memory—but it’s difficult to investigate the neuroscience of movement or behavior when your subjects can’t move around and behave.

How the Heck:

The new device is a fluorescence microscope, meaning it shines light on a sample, then captures the glow that bounces back. Despite the scope’s tiny size, the researchers fit all the necessary optical components—lenses, sensors, a mirror, an LED light, and more—inside it. In addition to being mobile, the microscope captures the activity of more cells ...

How Human Are You? A New Turing Test Relies on Spatial Relations

Veronique Greenwood — Wed, 14 Sep 2011 19:56:08 +0000

Where is the cup? THERE IS NO CUP.

What’s the News: Ever since Alan Turing, the father of modern computers, proposed that sufficiently advanced computers could pass as human in a conversation, the classic Turing test has involved what’s essentially instant messaging. Computers designed to imitate human conversational patterns are often entered by their designers in competitions where they aim to fool people in front of a distant monitor into thinking they’re human—and they do a pretty good job, although some human mimics, like chatbots, sound like crazed children on their first spin in cyberspace (“I’m not a robot, I’m a unicorn!“).

But scientists have noticed that humans describe where objects are in space in a specific way, taking into account what spatial relationships would be most useful for a human listener. Artificial intelligences, even fairly sophisticated ones, talk about space differently, and the difference is large enough that it can form the basis of a new type of Turing test, British scientists reported at a conference in April. Now, New Scientist has developed an interactive version of the test, which lets you see for yourself what statements about space set off your silicon-lifeform alarms. ...

SpongeBob: Not the Best Test Prep for Your 4-Year-Old

Douglas Main — Tue, 13 Sep 2011 18:32:35 +0000

A study published yesterday in the journal Pediatrics found that pre-schoolers who watched a nine-minute clip of Nickledeon’s SpongeBob SquarePants scored lower on a variety of cognitive tests given to them immediately afterward, compared to peers who spent the same time watching an educational PBS show or drawing. Although the researchers don’t specifically call out SpongeBob (one of the most popular shows amongst children ages 2-11), they conclude that fast-paced, entertainment-oriented shows like this, which rapidly cut between different scenes, could cause short-term reductions in children’s ability to focus and solve problems.

That may sound ominous, but it’s important to note that the study only looked at children immediately after watching the show, so there’s no evidence that this effect will persist. And although previous research has shown a clear association between watching television at a young age and attention problems later in life, it’s not clear whether TV—or any particular shows—are actually causing long-term problems. Still, if your 4-year-old is about to take a preschool entrance exam, it’s probably not the best time for a SpongeBob marathon.

[Via the Los Angeles Times]

Insulin Spray May Stave Off Alzheimer’s, Preliminary Study Suggests

Valerie Ross — Tue, 13 Sep 2011 16:49:20 +0000

A twice-daily dose of insulin, sprayed deep in the nose for easy transit to the brain, may slow or stop the progression of Alzheimer’s disease, according to a new pilot study. The researchers gave 104 patients with mild to moderate Alzheimer’s disease or pre-Alzheimer’s cognitive impairment one of three nasal sprays for four months. One group of patients got a nasal spray with a moderate dose of insulin twice a day, one group got a higher dose, and the third got a squirt of saline solution, as a placebo. The memory, cognitive abilities, and day-to-day functioning of patients given insulin stayed constant or improved slightly—particularly for those given the moderate dose of insulin rather than the high dose—while the abilities and memory of patients given the placebo declined.

It makes sense that insulin might slow the advance of the disease. In addition to its effect on blood sugar levels, insulin seems to guard against some of the ill effects of the amyloid plaques that build up in the brains of Alzheimer’s patients. Diabetics and other people whose bodies produce too little insulin or aren’t responsive to it are more ...

Fatherhood Lowers Men’s Testosterone, But the Causes Remain Murky

Veronique Greenwood — Tue, 13 Sep 2011 16:42:41 +0000

If having kids has made you feel like less of a party animal, men, you now have some science backing you up. A new study following men from their single salad days through the early years of their children’s lives found that fathers had a steeper decline in testosterone levels than men who remained single and childless. Though previous studies had indicated that fathers had lower testosterone, this is the first study to look at men before and after fatherhood, showing that it’s not just that lower-testosterone males are more likely to become dads. (In fact, this study shows the opposite—it’s the hormone-pumped guys who are more likely to settle down with a partner and have kids.)

But testosterone declines naturally with age, and stress is known to contribute to cellular aging. Is the accelerated decline because zero sleep, frayed nerves, and other byproducts of procreating are making men old before their time? That’s a question for next time—this study doesn’t address the decline’s cause.

Image courtesy of edenpictures / flickr

How to Make a Transparent Mouse with a Few Simple Ingredients

Veronique Greenwood — Wed, 31 Aug 2011 19:02:04 +0000

On the left: A mouse embryo preserved in para-formaldehyde. On the right: A mouse embryo soaked in Scale for two weeks.

What’s the News: The trouble with brains, organs, and tissues in general, from a biologist’s perspective, is that they scatter light like nobody’s business. Shine a light into there to start snapping pictures of cells with your microscope, and bam, all those proteins and macromolecules bounce it around and turn everything to static before you’ve gotten more than a millimeter below the surface. Scientists at RIKEN in Japan, however, have just published a special recipe for a substance that makes tissue as transparent as Jell-O, making unprecedentedly deep imaging possible.

How the Heck:

Substances to make tissue more transparent are called clearing agents, and the ones we have now have varying degrees of penetration—in other words, they don’t always take you as deep as you’d like. To boot, they sometimes mess with the fluorescent tags that biologists splice into certain tissues to light up a particular set of blood vessels or neurons, for example. This recipe clears out tissue so well that the only limitation on how deep you can see is the power of ...

Is Culture Behind Men’s Better Spatial Reasoning?

Joseph Castro — Tue, 30 Aug 2011 20:12:20 +0000

What’s the News: In the long-running debate over the differences between men and women, one mental skill has emerged as being perhaps more biologically rooted than any other: the ability to solve problems involving physical spaces, shapes, or forms. Many studies have concluded that men simply seem to have an inherent advantage in this area. But a new study of two tribes in Northern India is suggesting that the gender gap we see in spatial skills may be partially due to culture rather than raw biology. This finding may affect the way researchers look at gender differences, but it will surely not settle the question, considering that it’s one study of a small group of people living in one limited environment.

How the Heck:

Economist Moshe Hoffman and his colleagues recruited 1,279 participants from two neighboring tribes in northern India, the Karbi and the Khasi. The two tribes are similar in many ways: they only separated a few hundred years ago and they are both made up of subsistence farmers mainly ...

Confirmed: Kids of Older Dads At High Risk of Mental Illness. But Why?

Valerie Ross — Mon, 29 Aug 2011 20:22:15 +0000

Children of older mothers, scientists have long known, are at higher risk for certain genetic disorders such as Down syndrome. But the father’s age is matters, too. As a father’s age increases, research shows, so does his child’s risk of mental illness, schizophrenia and autism in particular. In Scientific American, Nicole Grey explores the link between a father’s age and his child’s health, as well as the tricky questions about what mechanisms are behind the that link: genes, epigenetic changes, environment, or some combination of the three.

Some researchers suggest that epigenetic changes, alterations in how genes are expressed, that occur over a man’s lifetime may be passed down to his children, triggering such diseases, or that genetic mutations in sperm may make children more vulnerable to developing psychiatric disorders, rather than directly causing the condition. And for all the worry about genetic changes in a woman’s eggs once she passes 35, a man’s sperm has ample opportunity to accumulate mutations, too:

When it comes to reproductive outcomes, older men are actually disadvantaged compared with older women, due to the high rate of sperm cell division. [Psychiatry professor John] McGrath points out ...

A Brainy New Chip Could Make Computers More Like Humans

Valerie Ross — Fri, 19 Aug 2011 16:50:34 +0000

One of IBM’s prototype cognitive computing chips

What’s the News: Researchers at IBM have developed a new “cognitive computing” microchip inspired by the brain’s computational tricks. These new chips, the researchers say, could make processors that are more powerful and more efficient than today’s computers—and better at the flexible learning and responses that are a struggle for current AI systems but a breeze for the human brain.

How the Heck:

IBM has made two prototypes of the new chip, which it calls a “neurosynaptic core.” Both are built on a standard semiconductor platform with 256 “neurons,” the chip’s computational components. RAM units on the chip act as synapses; one of the chips has 262,144 synapses, while the other has 65,536. These networks take after the brain in two key ways, says Dharmendra Modha, the project leader at IBM. The hardware for memory and computation are quite close together (as they are in the brain, where neurons are responsible for both) and the connections between them form, strengthen, and weaken based on learning and experience, just like synapses between neurons. Other than that, the researchers haven’t yet shared many specifics on how the ...

Why Do the Innocent Confess?

Valerie Ross — Fri, 12 Aug 2011 16:17:22 +0000

In the justice system, a confession is often treated as proof of guilt—and yet, a surprising number of people confess to crimes they didn’t commit. In its latest issue, the Economist reviews recent research showing just how frequently innocent people ‘fess up, and what factors lead them to do it.

When an experimenter falsely accused subjects of crashing a computer, 25% of them confessed even though they’d done nothing wrong, one study found. If the accusation was corroborated by a (lying) eyewitness, that number jumped to 80%. In another study, participants falsely accused of cheating on a task were told that authority figures were processing evidence that could prove their guilt—in this case, a tape. Half the people confessed, even though they must have known the tape recorded their actual, innocent behavior. This is particularly worrying because police often use this same tactic when waiting to get DNA or fingerprint results.

While the situations—research subject vs. crime suspect—are of course quite different, the parallels are enough to give one pause.

Read the full story at the Economist.

Image courtesy of Pearson Scott Foresman / Wikimedia Commons

A Mental Abacus Lets Math Whizzes Bypass Language

Veronique Greenwood — Tue, 09 Aug 2011 18:52:47 +0000

What’s the News: Most of us need everyone to stop talking when we perform mental math. But for children trained to do math visually with a “mental abacus,” verbal disturbances roll off their backs, prompting psychologists to posit that unlike the rest of us, they aren’t routing their calculations through words.

What’s the Context:

While some of the most brilliant mathematicians have been known for their ability to “think in shapes,” and Einstein said he used “sensations of a kinesthetic or muscular type” to come up with his breakthroughs, math is usually taught much like reading: a system of symbols to be interpreted. It’s been suggest that the mental abacus, a system in which children are taught to use a physical abacus and then learn to manipulate it mentally, uses visual, rather than verbal, brain processes, judging from fMRI studies. And it seems to work phenomenally well: the winner of the 2010 Mental Calculation World Cup was an 11-year-old girl trained in mental abacus. But working memory, the ability to juggle a few things in the front of one’s mind during activities like mental math, is known to have distinct size limitations. Generally, the number ...

Could Next-Gen Drugs Turn Off Genes in the Brain?

Valerie Ross — Thu, 04 Aug 2011 17:28:12 +0000

Current drugs for conditions from depression to Parkinson’s work by changing levels of chemicals in the brain—an imprecise method that can have a wide range of unintended effects. But a new study suggests it could be possible to make drugs that work by turning off genes instead, getting at, for instance, a specific receptor in a particular part of the brain.

The researchers attached an anti-depressant, setraline, to a bit of what’s called small interfering RNA. They found that when mice were given the combo nasally, it shut off a particular serotonin receptor thought to be involved in depression in just the region of the brain they were aiming for, and nowhere else. On his blog, Neuroskeptic points out that it’s not clear when, or if, the drug will be ready for humans—but wow, is that an exciting idea:

The mind boggles at the potential. If you could selectively alter the gene expression of selective neurons, you could do things to the brain that are currently impossible. Existing drugs hit the whole brain, yet there are many reasons why you’d prefer to only affect certain areas. And editing gene expression would allow ...

People With Dyslexia Have Difficulty Not Just Reading Words, But Recognizing Voices

Valerie Ross — Wed, 03 Aug 2011 18:53:55 +0000

What’s the News: While most people think of dyslexia as primarily a problem with reading, people with dyslexia seem to have trouble processing the spoken language, as well. A new study published last week Science found that people with dyslexia have a harder time recognizing voices than other people do.

How the Heck:

Participants in the study–half of whom were dyslexic–watched and listened to cartoon characters on a computer. Each character had a distinct voice, and spoke either English, the participants’ native language, or Mandarin Chinese. The participants were then played a clip of each voice and asked to match it to the correct character. People without reading difficulties were better at recognizing voices speaking their native language. They could correctly pick out which character went with a voice about two-thirds of the time if the voice was speaking English, and only about half the time if it was speaking Mandarin. Dyslexics, on the other hand, showed no native language boost. It didn’t matter if a voice was speaking English or Mandarin: they correctly matched it with a character around half the time either way.

What’s the Context:

Researchers are increasingly finding that reading problems, while the most well known feature of dyslexia, are ...