Most Recent Links

Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.


Links 1 - 20 of 21287

Laura Sanders The brain can bounce back after a single head hit, but multiple hits in quick succession don’t give the brain time to recover, a new study suggests. Although the finding comes from mice, it may help scientists better understand the damage caused by repetitive impacts such as those sustained in football, soccer and other contact sports. The results, published in the March issue of the American Journal of Pathology, hint that a single, mild head hit isn’t necessarily cause for alarm. “There are things to be afraid of after a concussion,” says study coauthor Mark Burns of Georgetown University Medical Center in Washington, D.C. “But not every concussion is going to cause long-term damage.” Burns and his colleagues subjected some mice to a single, mild head hit. The relatively weak hit consistently slowed anesthetized mice’s return to consciousness, but didn’t cause major trauma. The impact was designed to mimic a mild traumatic brain injury, or concussion, in a person. Tests a day after the impact showed that about 13 percent of dendritic spines, docking sites that help connect brain cells, had vanished in a particular part of the brain. Three days after the injury, these missing connections reappeared, even surpassing the original number of connections. This fluctuating number of dendritic spines may actually help the brain recover, Burns says. “The cells weren’t dying,” he says. “They were responding to the injury.” © Society for Science & the Public 2000 - 2016.

Keyword: Brain Injury/Concussion
Link ID: 21867 - Posted: 02.06.2016

By Jeneen Interlandi The human brain’s memory-storage capacity is an order of magnitude greater than previously thought, researchers at the Salk Institute for Biological Studies reported last week. The findings, recently detailed in eLife, are significant not only for what they say about storage space but more importantly because they nudge us toward a better understanding of how, exactly, information is encoded in our brains. The question of just how much information our brains can hold is a longstanding one. We know that the human brain is made up of about 100 billion neurons, and that each one makes 1,000 or more connections to other neurons, adding up to some 100 trillion in total. We also know that the strengths of these connections, or synapses, are regulated by experience. When two neurons on either side of a synapse are active simultaneously, that synapse becomes more robust; the dendritic spine (the antenna on the receiving neuron) also becomes larger to support the increased signal strength. These changes in strength and size are believed to be the molecular correlates of memory. The different antenna sizes are often compared with bits of computer code, only instead of 1s and 0s they can assume a range of values. Until last week scientists had no idea how many values, exactly. Based on crude measurements, they had identified just three: small, medium and large. But a curious observation led the Salk team to refine those measurements. In the course of reconstructing a rat hippocampus, an area of the mammalian brain involved in memory storage, they noticed some neurons would form two connections with each other: the axon (or sending cable) of one neuron would connect with two dendritic spines (or receiving antennas) on the same neighboring neuron, suggesting that duplicate messages were being passed from sender to receiver. © 2016 Scientific American

Keyword: Learning & Memory
Link ID: 21866 - Posted: 02.06.2016

Colombia says three people have died after contracting the Zika virus and developing a rare nerve disorder. Health Minister Alejandro Gaviria said there was a "causal connection" between Zika, the Guillain-Barre disorder and the three deaths. Earlier, Brazilian scientists said they had detected for the first time active samples of Zika in urine and saliva. However, it is not clear whether the virus can be transmitted through bodily fluids. Zika, a mosquito-borne disease, has been linked to cases of babies born in Brazil with microcephaly - underdeveloped brains. "We have confirmed and attributed three deaths to Zika," said the head of Colombia's National Health Institute, Martha Lucia Ospina. "In this case, the three deaths were preceded by Guillain-Barre syndrome." Guillain-Barre is a rare disorder in which the body's immune system attacks part of the nervous system. It isn't normally fatal. Ms Ospina said another six deaths were being investigated for possible links to Zika. "Other cases (of deaths linked to Zika) are going to emerge," she said. "The world is realising that Zika can be deadly. The mortality rate is not very high, but it can be deadly." Mr Gaviria said one of the fatalities took place in San Andres and the other two in Turbo, in Antioquia department. UK virologist Prof Jonathan Ball, of the University of Nottingham, told the BBC: "We have been saying Zika has been associated with Guillain-Barre. One of the complications of that could be respiratory failure. But it is still probably a very rare event." Although Zika usually causes mild, flu-like symptoms, it has been linked to thousands of suspected birth defects. However, it has not yet been proved that Zika causes either microcephaly or Guillain-Barre. © 2016 BBC

Keyword: Movement Disorders; Neuroimmunology
Link ID: 21865 - Posted: 02.06.2016

Could a painkiller turn people away from suicide? A preliminary trial of an opioid called buprenorphine shows that the drug can reduce suicidal thoughts after just one week. If validated in larger studies, it could become the first fast-acting anti-suicide drug. Such a drug is sorely needed. The US Centers for Disease Control and Prevention (CDC) estimates that more than 9 million adults in the country reported having suicidal thoughts in 2013. Over a million went on to attempt suicide. “Around 400,000 suicidal people are coming to emergency rooms every year,” says Elizabeth Ballard at the National Institute of Mental Health. “Pharmacologically, nothing has been approved for acute treatment of suicidal ideation so anything that can help them is greatly needed.” When people seek help, they may be offered behavioural therapy or drugs such as antidepressants. But neither of these is guaranteed to alleviate feelings, and both can take six weeks or more to kick in. Ketamine, a drug being considered as an immediate treatment, can cause hallucinations and its effects wear off quickly. “Having something you could use on your own outside of a hospital would be beneficial,” says Ballard. Jaak Panksepp at Washington State University and his colleagues decided to see whether an opioid can counter suicidal feelings. Opioids are one of the brain’s natural feel-good chemicals. They are released to relieve pain when we hurt ourselves, and are involved when we deal with mental pain, such as that caused by social rejection, a common trigger for suicidal thoughts. © Copyright Reed Business Information Ltd.

Keyword: Depression; Drug Abuse
Link ID: 21864 - Posted: 02.06.2016

By Jonathan Leo Last week, according to many media accounts, scientists from Harvard Medical School, Boston Children’s Hospital, and the Broad Institute discovered the genetic basis of schizophrenia. The researchers reported in Nature that people with schizophrenia were more likely to have the overactive forms of a gene called complement component 4, or C4, which is involved in pruning synapses during adolescence. However, suggesting a biologic mechanism for a small subset of those diagnosed with schizophrenia is not the same as confirming the genetic theory of schizophrenia. Benedict Carey, science reporter for the New York Times, delved into the details and reported the all-important fact that having the C4 variant would increase a person’s risk by about 25 percent over the 1-percent base rate of schizophrenia—that is, to 1.25 percent. Genes for schizophrenia and depression have been discovered before, and in those cases, the subsequent enthusiastic headlines were shortly followed by retractions and more sober thinking. There are so many open questions (for instance, why do many people with the problematic variant not develop schizophrenia, and why do many people who don’t have the variant develop schizophrenia?) that the same may occur with the C4 discovery. The idea that mental illness is the result of a genetic predisposition is the foundation for modern-day psychiatry and has been the driving force for how research money is allocated, how patients are treated, and how society views people diagnosed with conditions identified in the Diagnostic and Statistical Manual of Mental Disorders, 5th Edition. Schizophrenia holds a unique spot in the annals of mental health research because of its perceived anatomical underpinnings and is often cited as evidence in favor of a genetic predisposition to other conditions.

Keyword: Schizophrenia; Genes & Behavior
Link ID: 21863 - Posted: 02.06.2016

Rare ‘allergy’ to vibrations tied to faulty gene By Kelly Servick If you have the rare condition known as vibratory urticaria, you may be wary of handling lawnmowers and electric mixers. Rubbing or vibration against your skin—even from drying off with a towel—can cause you to break out in hives, make your face flush, give you headaches, or produce the sensation of a metallic taste. The condition, which runs in families, is so rare that the researchers who work on it have only tracked down a few cases over years of searching. But a genetic study on three such unique families has revealed a potential mechanism for the strange symptoms. Research published online today in the New England Journal of Medicine describes a mutation in a gene called ADGRE2, found in 22 people with vibratory urticaria, but not in 14 of their unaffected relatives. The gene codes for a receptor protein that was found on the surface of mast cells—immune cells in the skin that dump out inflammatory molecules such as histamines that increase blood flow to an area and can cause hives. The researchers observed that shaking mast cells in a dish breaks apart two subunits of this receptor protein, which prompts histamine release. In people with the newly discovered mutation, the receptor is more prone to breakage, which causes this protective immune response at the site of physical trauma to run amok. © 2016 American Association for the Advancement of Science.

Keyword: Pain & Touch; Genes & Behavior
Link ID: 21862 - Posted: 02.06.2016

By JOHN BRANCH Shortly before he died in July, the former N.F.L. quarterback Ken Stabler was rushed away by doctors, desperate to save him, in a Mississippi hospital. His longtime partner followed the scrum to the elevator, holding his hand. She told him that she loved him. Stabler said that he loved her, too. “I turned my head to wipe the tears away,” his partner, Kim Bush, said recently. “And when I looked back, he looked me dead in the eye and said, ‘I’m tired.’ ” They were the last words anyone in Stabler’s family heard him speak. “I knew that was it,” Bush said. “I knew that he had gone the distance. Because Kenny Stabler was never tired.” The day after Stabler died on July 8, a victim of colon cancer at 69, his brain was removed during an autopsy and ferried to scientists in Massachusetts. It weighed 1,318 grams, or just under three pounds. Over several months, it was dissected for clues, as Stabler had wished, to help those left behind understand why his mind seemed to slip so precipitously in his final years. On the neuropathologist’s scale of 1 to 4, Stabler had high Stage 3 chronic traumatic encephalopathy, or C.T.E., the degenerative brain disease believed to be caused by repeated blows to the head, according to researchers at Boston University. The relationship between blows to the head and brain degeneration is still poorly understood, and some experts caution that other factors, like unrelated mood problems or dementia, might contribute to symptoms experienced by those later found to have had C.T.E. Stabler, well known by his nickname, the Snake (“He’d run 200 yards to score from 20 yards out,” Stabler’s junior high school coach told Sports Illustrated in 1977), is one of the highest-profile football players to have had C.T.E. The list, now well over 100 names long, includes at least seven members of the Pro Football Hall of Fame, including Junior Seau, Mike Webster and Frank Gifford. © 2016 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 21861 - Posted: 02.04.2016

By Diana Kwon Antidepressants are some of the most commonly prescribed medications out there. More than one out of 10 Americans over age 12—roughly 11 percent—take these drugs, according to a 2011 report by the National Center for Health Statistics. And yet, recent reports have revealed that important data about the safety of these drugs—especially their risks for children and adolescents—has been withheld from the medical community and the public. In the latest and most comprehensive analysis, published last week in BMJ (the British Medical Journal),a group of researchers at the Nordic Cochrane Center in Copenhagen showed that pharmaceutical companies were not presenting the full extent of serious harm in clinical study reports, which are detailed documents sent to regulatory authorities such as the U.S. Food and Drug Administration and the European Medicines Agency (EMA) when applying for approval of a new drug. The researchers examined documents from 70 double-blind, placebo-controlled trials of two common types of antidepressants—selective serotonin reuptake inhibitors (SSRI) and serotonin and norepinephrine reuptake inhibitors (SNRI)—and found that the occurrence of suicidal thoughts and aggressive behavior doubled in children and adolescents who used these medications. This paper comes on the heels of disturbing charges about conflicts of interest in reports on antidepressant trials. Last September a study published in the Journal of Clinical Epidemiology revealed that a third of meta-analyses of antidepressant studies were written by pharma employees and that these were 22 times less likely than other meta-studies to include negative statements about the drug. © 2016 Scientific American

Keyword: Depression
Link ID: 21860 - Posted: 02.04.2016

By Christian Jarrett Back in the 1980s, the American scientist Benjamin Libet made a surprising discovery that appeared to rock the foundations of what it means to be human. He recorded people’s brain waves as they made spontaneous finger movements while looking at a clock, with the participants telling researchers the time at which they decided to waggle their fingers. Libet’s revolutionary finding was that the timing of these conscious decisions was consistently preceded by several hundred milliseconds of background preparatory brain activity (known technically as “the readiness potential”). The implication was that the decision to move was made nonconsciously, and that the subjective feeling of having made this decision is tagged on afterward. In other words, the results implied that free will as we know it is an illusion — after all, how can our conscious decisions be truly free if they come after the brain has already started preparing for them? For years, various research teams have tried to pick holes in Libet’s original research. It’s been pointed out, for example, that it’s pretty tricky for people to accurately report the time that they made their conscious decision. But, until recently, the broad implications of the finding have weathered these criticisms, at least in the eyes of many hard-nosed neuroscientists, and over the last decade or so his basic result has been replicated and built upon with ever more advanced methods such as fMRI and the direct recording of neuronal activity using implanted electrodes. © 2016, New York Media LLC

Keyword: Consciousness
Link ID: 21859 - Posted: 02.04.2016

By Susana Martinez-Conde Take a look at the red chips on the two Rubik cubes below. They are actually orange on the left and purple on the right, if you look at them in isolation. They only appear more or less equally red across the images because your brain is interpreting them as red chips lit by either yellow or blue light. This kind of misperception is an example of perceptual constancy, the mechanism that allows you to recognize an object as being the same in different environments, and under very diverse lighting conditions. Constancy illusions are adaptive: consider what would have happened if your ancestors thought a friend became a foe whenever a cloud hid the sun, or if they lost track of their belongings–and even their own children—every time they stepped out of the cave and into the sunlight. Why, they might have even eaten their own kids! You are here because the perceptual systems of your predecessors were resistant to annoying changes in the physical reality–as is your own (adult) perception. There are many indications that constancy effects must have helped us survive (and continue to do so). One such clue is that we are not born with perceptual constancy, but develop it many months after birth. So at first we see all differences, and then we learn to ignore certain types of differences so that we can recognize the same object as unchanging in many varied scenarios. When perceptual constancy arises, we lose the ability to detect multiple contradictions that are nevertheless highly noticeable to young babies. © 2016 Scientific American

Keyword: Vision; Development of the Brain
Link ID: 21858 - Posted: 02.04.2016

Mo Costandi The human brain is immediately recognizable by its cortex (meaning bark in Latin), the prominent outer layer of tissue, with its characteristic pattern of ridges and furrows, which sits atop the deep structures. The cortex is just several millimetres thick, but has a surface area of about two-and-a-half square feet, and is therefore heavily convoluted so it can be packed into the skull. This fleshy landscape begins to form during the second trimester of pregnancy, and continues into the first year of life. It is often assumed to be the result of genetics, like most other aspects of brain development. Forty years ago, however, Harvard researchers put forward the controversial idea that the brain folds up because of physical forces, and a new study now provides the first evidence this. According to this old model, the brain’s folds form as a result of differential growth which causes the cortex to grow in size far more quickly than other brain structures, leading it to buckle and fold as its surface area increases, due to the constraints of the skull. To test this, Tuomos Tallinen of the University of Jyväskylä in Finland and his colleagues used magnetic resonance images to create a 3D-printed cast of an unfolded 22-week-old human brain. This was made with a technique called layer-by-layer drop casting, and consisted of a soft polymer core coated with a thin sheet of an absorbent elastomer gel representing the cortex. © 2016 Guardian News and Media Limited

Keyword: Development of the Brain
Link ID: 21857 - Posted: 02.04.2016

By Nicholas Bakalar Women with sleeping difficulties are at increased risk for Type 2 diabetes, researchers report. Scientists used data from 133,353 women who were generally healthy at the start of the study. During 10 years of follow-up, they found 6,407 cases of Type 2 diabetes. The researchers looked at four sleep problems: self-reported difficulty falling or staying asleep, frequent snoring, sleep duration of less than six hours, and either sleep apnea or rotating shift work. The study is in Diabetologia. Self-reported difficulty sleeping was associated with higher B.M.I., less physical activity, and more hypertension and depression. But even after adjusting for these and other health and behavioral characteristics, sleeping difficulty was still associated with a 22 percent increased risk for Type 2 diabetes. Compared to women with no sleep problems, those with two of the sleep conditions studied had double the risk, and those with all four had almost four times the risk of developing the illness. The senior author, Dr. Frank B. Hu, a professor of nutrition and epidemiology at Harvard, said that sleep problems are associated with excess secretion of two hormones: ghrelin, which increases appetite, and cortisol, which increases stress and insulin resistance. Both are linked to metabolic problems that increase the risk for diabetes. “And,” he added, “it’s not just quantity of sleep, but quality as well” that is associated with these health risks. © 2016 The New York Times Company

Keyword: Sleep; Obesity
Link ID: 21856 - Posted: 02.04.2016

Heidi Ledford Difficulty with concentration, memory and other cognitive tasks is often associated with depression. In the past quarter of a century, a wave of drugs has transformed the treatment of depression. But the advances have struggled to come to grips with symptoms that often linger long after people start to feel better: cognitive problems such as memory loss and trouble concentrating. On 3 February, the US Food and Drug Administration (FDA) will convene a meeting of its scientific advisers to discuss whether such cognitive impairments are components of the disorder that drugs might be able to target — or just a result of depressed mood. The discussion will help the agency to decide whether two companies that sell the antidepressant vortioxetine should be allowed to label it as a treatment for the cognitive effects. A ‘yes’ could spur drug developers to invest in ways to test cognitive function during their antidepressant trials. Psychiatrists have long noted that some people with depression also struggle to concentrate and to make decisions. The question has been whether such difficulties are merely an offshoot of altered mood and would thus clear up without specific treatment, says Diego Pizzagalli, a neuroscientist at McLean Hospital, an affiliate of Harvard Medical School in Belmont, Massachusetts. But some patients who report improved mood after treatment still struggle with cognitive deficits — so psychiatrists sometimes prescribe concentration-enhancing drugs that are approved to treat attention deficit hyperactivity disorder to people with depression. © 2016 Nature Publishing Group

Keyword: Depression; Attention
Link ID: 21855 - Posted: 02.03.2016

Fears over surveillance seem to figure large in the bird world, too. Ravens hide their food more quickly if they think they are being watched, even when no other bird is in sight. It’s the strongest evidence yet that ravens have a “theory of mind” – that they can attribute mental states such as knowledge to others. Many studies have shown that certain primates and birds behave differently in the presence of peers who might want to steal their food. While some researchers think this shows a theory of mind, others say they might just be reacting to visual cues, rather than having a mental representation of what others can see and know. Through the peephole Thomas Bugnyar and colleagues at the University of Vienna, Austria, devised an experiment to rule out the possibility that birds are responding to another’s cues. The setup involved two rooms separated by a wooden wall, with windows and peepholes that could be covered. First, a raven was given food with another raven in the next room, with the window open or covered, to see how quickly it caches its prize. With the window open, the birds hid their food more quickly and avoided going back to conceal it further. Then individual ravens were then trained to use the peephole to see where humans were putting food in the other room. The idea here was to allow the bird to realise it could be seen through the peephole. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Evolution
Link ID: 21854 - Posted: 02.03.2016

By Anna K. Bobak, Sarah Bate For years scientists have studied the biological basis of human speed, and reported that the fastest athletes are short and muscular in build. However, these conclusions were challenged in 2008 when a new athlete, substantially taller than previous world-record holders, was identified as the fastest man in history. Usain Bolt presented the purest expression of human speed on the planet – and raised the possibility that scientists may need to entirely change the way they think about human biometrics. In the same vein, one might ask whether examinations of the brain at its height of efficiency will present new insights into its workings. Although researchers have historically examined people with a very high IQ (i.e. those with more generalised skills), it has become more and more clear that some individuals only perform extraordinarily well on specific cognitive tasks. Among the most interesting of these is facial identity recognition. In fact, the extraordinary skills of these so-called “super-recognisers” do not seem to correlate with IQ or memory for objects, yet they claim to recognise faces which they have only briefly been seen before, or have undergone substantial changes in appearance. For instance, in a recent scientific report from our laboratory (unpublished), one super-recogniser described bumping into a girl from a children’s’ swimming class he coached as a teenager. He recognised her immediately, despite the fact that he’d not seen her for over ten years and she was now an adult. So how can these people change the way that scientists think about the human brain? For many years researchers have generally agreed that faces are “special.” © 2016 Scientific American

Keyword: Attention
Link ID: 21853 - Posted: 02.03.2016

By JAN HOFFMAN One evening in the late fall, Lucien Majors, 84, sat at his kitchen table, his wife Jan by his side, as he described a recent dream. Mr. Majors had end-stage bladder cancer and was in renal failure. As he spoke with a doctor from Hospice Buffalo , he was alert but faltering. In the dream, he said, he was in his car with his great pal, Carmen. His three sons, teenagers, were in the back seat, joking around. “We’re driving down Clinton Street,” said Mr. Majors, his watery, pale blue eyes widening with delight at the thought of the road trip. “We were looking for the Grand Canyon.” And then they saw it. “We talked about how amazing, because there it was — all this time, the Grand Canyon was just at the end of Clinton Street!” Mr. Majors had not spoken with Carmen in more than 20 years. His sons are in their late 50s and early 60s. “Why do you think your boys were in the car?” asked Dr. Christopher W. Kerr, a Hospice Buffalo palliative care physician who researches the therapeutic role of patients’ end-of-life dreams and visions. “My sons are the greatest accomplishment of my life,” Mr. Majors said. He died three weeks later. For thousands of years, the dreams and visions of the dying have captivated cultures, which imbued them with sacred import. Anthropologists, theologians and sociologists have studied these so-called deathbed phenomena. They appear in medieval writings and Renaissance paintings, in Shakespearean works and set pieces from 19th-century American and British novels, particularly by Dickens. One of the most famous moments in film is the mysterious deathbed murmur in “Citizen Kane”: “Rosebud!” Even the law reveres a dying person’s final words, allowing them to be admitted as evidence in an unusual exception to hearsay rules. © 2016 The New York Times Company

Keyword: Sleep
Link ID: 21852 - Posted: 02.03.2016

By Sarah Knapton, Science Editor For women, shedding the pounds can feel like a unending struggle of dieting and exercise with little results. But a new study suggests that there could be a reason why females find it more difficult to lose weight than men. Researchers say hormones responsible for regulating appetite, physical activity and energy expenditure work differently in the sexes. "This could have broad implications for medications used to combat obesity, which at present largely ignore the sex of the individual." Professor Lora Heisler, University of Aberdeen The discovery could change the way obesity is tackled through targeted medication, experts at the University of Aberdeen believe. Working with teams from the University of Cambridge and the University of Michigan, they used a mouse model to study how weight gain differs in each sex depending on physical activity and energy expenditure. During the study, researchers were able to transform obese male into lean, healthy mice, but the same transformation did not occur in the female mice. Current obesity medications stimulate the production of POMC peptides in the brain which regulate appetite, increase energy expenditure through heat and encourage movement. But researchers found in female mice the hormones only regulated appetite - they did not have the extra benefits. © Copyright of Telegraph Media Group Limited 2016

Keyword: Obesity; Sexual Behavior
Link ID: 21851 - Posted: 02.03.2016

By Laurel Hamers As one person at the dinner table leans back, stretches, and opens their mouth in a gaping yawn, others will soon follow suit. Catching a yawn is more likely to occur between relatives than strangers, and scientists believe it’s sign of empathy. Plus, other social primates like chimps and bonobos do it, too. A new study suggests that women (traditionally branded the more empathetic sex) might be more susceptible to copycat yawning than men. Researchers surreptitiously analyzed more than 4000 real-world yawns on planes and trains, in restaurants, and in offices. They noted when someone yawned, and then whether a nearby acquaintance or friend did the same within a 3-minute period. Men and women spontaneously yawned with about the same frequency. But when someone else yawned first, women were more likely than men to follow suit. Women picked up yawns about 55% of the time, whereas men only did so 40% of the time. Women tend to score higher than men on tests of empathy, and traditional female social roles (like child-rearing) place a higher emphasis on those traits. That might make women more attuned to others’ yawns, the researchers suggest. Gender roles aren’t as rigid in our modern society—but the yawning gap appears to linger. © 2016 American Association for the Advancement of Science

Keyword: Emotions; Sexual Behavior
Link ID: 21850 - Posted: 02.03.2016

By SINDYA N. BHANOO Several studies suggest that men find women more attractive when they are in the ovulatory phase of their menstrual cycle. The thesis takes a strange turn in a new study in which women were questioned: Each subject was asked whether a woman in an image was likely to entice a man that she was dating. Although women do not find images of ovulatory women particularly attractive, scientists found, women with higher estrogen levels did perceive such images to be more threatening. Women with high estrogen, the researchers noted, have a high potential for fertility. “We’re still trying to pinpoint exactly what all is involved in this,” said Janek S. Lobmaier, a psychologist at the University of Bern. © 2016 The New York Times Company

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 21849 - Posted: 02.02.2016

By Jonathan Webb Science reporter, BBC News Scientists have reproduced the wrinkled shape of a human brain using a simple gel model with two layers. They made a solid replica of a foetal brain, still smooth and unfolded, and coated it with a second layer which expanded when dunked into a solvent. That expansion produced a network of furrows that was remarkably similar to the pattern seen in a real human brain. This suggests that brain folds are caused by physics: the outer part grows faster than the rest, and crumples. Such straightforward, mechanical buckling is one of several proposed explanations for the distinctive twists and turns of the brain's outermost blanket of cells, called the "cortex". Alternatively, researchers have suggested that biochemical signals might trigger expansion and contraction in particular parts of the sheet, or that the folds arise because of stronger connections between specific areas. "There have been several hypotheses, but the challenge has been that they are difficult to test experimentally," said Tuomas Tallinen, a soft matter physicist at the University of Jyväskylä in Finland and a co-author of the study, which appears in Nature Physics. "I think it's very significant... that we can actually recreate the folding process using this quite simple, physical model." Humans are one of just a few animals - among them whales, pigs and some other primates - that possess these iconic undulations. In other creatures, and early in development, the cortex is smooth. The replica in the study was based on an MRI brain scan from a 22-week-old foetus - the stage just before folds usually appear. © 2016 BBC.

Keyword: Development of the Brain
Link ID: 21848 - Posted: 02.02.2016