Chapter 16. None

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By Diana Kwon Symptoms come and go in most cases of multiple sclerosis (MS), a chronic disease in which the immune system attacks myelin, the nonconductive sheath that surrounds neurons' axons. Yet 10 to 15 percent of cases are progressive rather than relapsing. This more severe version appears later in life and is marked by steadily worsening symptoms. No treatments are currently available, but that might be about to change. In September pharmaceutical company Hoffmann–La Roche announced positive results from three large clinical trials of ocrelizumab, an injectable antibody medication that targets B cells, for both relapsing and progressive MS. They found that the drug was more effective at treating relapsing MS than interferon beta-1a (Rebif), a top-performing drug now used to treat the disease. Even more exciting, it slowed the advance of symptoms in patients with progressive MS for the entire 12-week duration of the study. “The drug has dramatic effects on relapsing MS, and we finally have our foot in the door with the progressive form,” says Stephen Hauser, a neurologist at the University of California, San Francisco, who was involved in the trials. The fact that ocrelizumab works on both types of MS is a tantalizing clue for scientists trying to understand the root causes of the disease and figure out why the inflammation of the relapsing form eventually turns into progressive degeneration in some patients. “These results give evidence that the inflammatory and the degenerative components of MS are related,” Hauser says. “The big question now is, If we begin treatment really early, can we protect relapsing patients from developing the progressive problems later on?” © 2015 Scientific American

Keyword: Multiple Sclerosis
Link ID: 21724 - Posted: 12.27.2015

By KEN BELSON Researchers at several universities and research institutes were awarded almost $16 million Tuesday to find a way to diagnose, while victims are alive, chronic traumatic encephalopathy, a degenerative brain disease linked to repeated head hits in contact sports. The National Institutes of Health and the National Institute of Neurological Disorders and Stroke issued the seven-year grant as part of a long-term study of brain disease in former N.F.L. and college football players, many of whom sustained multiple concussions on the field. Despite the implications that the research may have on football players and the N.F.L., no league money will be used to help pay for the grant. For years, researchers have been able to diagnose C.T.E. only by examining the brains of players who died and whose families agreed to donate the organ, a limitation that has slowed efforts to determine who is susceptible to having the disease. The new study, considered among the most ambitious in the field of sports-related brain injury, aims to develop ways to spot the disease in the living and figure out why certain players get it and others do not. A more comprehensive understanding of the disease, the researchers said, may lead to ways to prevent it. “There are so many critical unanswered questions about C.T.E.,” Dr. Robert Stern, the lead principal investigator and a professor at Boston University School of Medicine, said in a statement. “We are optimistic that this project will lead to many of these answers, by developing accurate methods of detecting and diagnosing C.T.E. during life, and by examining genetic and other risk factors for this disease.” © 2015 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 21723 - Posted: 12.24.2015

By Elahe Izadi Tiny cameras attached to wild New Caledonian crows capture, for the first time, video footage of these elusive birds fashioning hooked stick tools, according to researchers. These South Pacific birds build tools out of twigs and leaves that they use to root out food, and they're the only non-humans that make hooked tools in the wild, write the authors of a study published Wednesday in the journal Biology Letters. Humans have previously seen the crows making the tools in artificial situations, in which scientists baited feeding sites and provided the raw tools; but researchers say the New Caledonian crows have never been filmed doing this in a completely natural setting. "New Caledonian crows are renowned for their unusually sophisticated tool behavior," the study authors write. "Despite decades of fieldwork, however, very little is known about how they make and use their foraging tools in the wild, which is largely owing to the difficulties in observing these shy forest birds." Study author Jolyon Troscianko of the University of Exeter in England described the tropical birds as "notoriously difficult to observe" because of the terrain of their habitat and their sensitivity to disturbance, he said in a press release. "By documenting their fascinating behavior with this new camera technology, we obtained valuable insights into the importance of tools in their daily search for food," he added.

Keyword: Evolution; Intelligence
Link ID: 21719 - Posted: 12.24.2015

A study of mice shows how proteasomes, a cell’s waste disposal system, may break down during Alzheimer’s disease, creating a cycle in which increased levels of damaged proteins become toxic, clog proteasomes, and kill neurons. The study, published in Nature Medicine and supported by the National Institutes of Health, suggests that enhancing proteasome activity with drugs during the early stages of Alzheimer’s may prevent dementia and reduce damage to the brain. “This exciting research advances our understanding of the role of the proteasomes in neurodegeneration and provides a potential way to alleviate symptoms of neurodegenerative disorders,” said Roderick Corriveau, Ph.D., program director at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS), which provided funding for the study. The proteasome is a hollow, cylindrical structure which chews up defective proteins into smaller, pieces that can be recycled into new proteins needed by a cell. To understand how neurodegenerative disorders affect proteasomes, Natura Myeku, Ph.D., a postdoctoral fellow working with Karen E. Duff, Ph.D., professor of pathology and cell biology at Columbia University, New York City, focused on tau, a structural protein that accumulates into clumps called tangles in the brain cells of patients with Alzheimer’s disease and several other neurodegenerative disorders known as tauopathies. Using a genetically engineered mouse model of tauopathy, as well as looking at cells in a dish, the scientists discovered that as levels of abnormal tau increased, the proteasome activity slowed down.

Keyword: Alzheimers
Link ID: 21716 - Posted: 12.22.2015

By John Bohannon In July 1984, a man broke into the apartment of Jennifer Thompson, a 22-year-old in North Carolina, and threatened her with a knife. She negotiated, convincing him to not kill her. Instead, he raped her and fled. Just hours later, a sketch artist worked with Thompson to create an image of the assailant's face. Then the police showed her a series of mug shots of similar-looking men. Thompson picked out 22-year-old Ronald Cotton, whose photograph was on file because of a robbery committed in his youth. When word reached Cotton that the police were looking for him, he walked into a precinct voluntarily. He was eventually sentenced to life in prison based on Thompson's testimony. Eleven years later, after DNA sequencing technology caught up, samples taken from Thomson's body matched a different man who finally confessed. Cotton was set free. When Thompson first identified Cotton by photo, she was not convinced of her choice. "I think this is the guy," she told the police after several minutes of hesitation. As time went on, she grew surer. By the time Thompson faced Cotton in court a year later, her doubts were gone. She confidently pointed to him as the man who raped her. Because of examples like these, the U.S. justice system has been changing how eyewitnesses are used in criminal cases. Juries are told to discount the value of eyewitness testimony and ignore how confident the witnesses may be about whom they think they saw. Now, a new study of robbery investigations suggests that these changes may be doing more harm than good. © 2015 American Association for the Advancement of Science

Keyword: Learning & Memory
Link ID: 21715 - Posted: 12.22.2015

Carl Zimmer Over the past few million years, the ancestors of modern humans became dramatically different from other primates. Our forebears began walking upright, and they lost much of their body hair; they gained precision-grip fingers and developed gigantic brains. But early humans also may have evolved a less obvious but equally important advantage: a peculiar sleep pattern. “It’s really weird, compared to other primates,” said Dr. David R. Samson, a senior research scientist at Duke University. In the journal Evolutionary Anthropology, Dr. Samson and Dr. Charles L. Nunn, an evolutionary biologist at Duke, reported that human sleep is exceptionally short and deep, a pattern that may have helped give rise to our powerful minds. Until recently, scientists knew very little about how primates sleep. To document orangutan slumber, for example, Dr. Samson once rigged up infrared cameras at the Indianapolis Zoo and stayed up each night to watch the apes nod off. By observing their movements, he tracked when the orangutans fell in and out of REM sleep, in which humans experience dreams. “I became nocturnal for about seven months,” Dr. Samson said. “It takes someone who wants to get their Ph.D. to be motivated enough to do that.” In the new study. Dr. Samson and Dr. Nunn combined that information with studies of 19 other primate species. The researchers found wide variations in how long the animals slept. Mouse lemurs doze for seventeen hours a day, for example, while humans sleep just seven hours or so a day — “the least of any primate on the planet,” said Dr. Samson. © 2015 The New York Times Company

Keyword: Sleep; Evolution
Link ID: 21712 - Posted: 12.19.2015

Scientists showed that they could alter brain activity of rats and either wake them up or put them in an unconscious state by changing the firing rates of neurons in the central thalamus, a region known to regulate arousal. The study, published in eLIFE, was partially funded by the National Institutes of Health. “Our results suggest the central thalamus works like a radio dial that tunes the brain to different states of activity and arousal,” said Jin Hyung Lee, Ph.D., assistant professor of neurology, neurosurgery and bioengineering at Stanford University, and a senior author of the study. Located deep inside the brain the thalamus acts as a relay station sending neural signals from the body to the cortex. Damage to neurons in the central part of the thalamus may lead to problems with sleep, attention, and memory. Previous studies suggested that stimulation of thalamic neurons may awaken patients who have suffered a traumatic brain injury from minimally conscious states. Dr. Lee’s team flashed laser pulses onto light sensitive central thalamic neurons of sleeping rats, which caused the cells to fire. High frequency stimulation of 40 or 100 pulses per second woke the rats. In contrast, low frequency stimulation of 10 pulses per second sent the rats into a state reminiscent of absence seizures that caused them to stiffen and stare before returning to sleep. “This study takes a big step towards understanding the brain circuitry that controls sleep and arousal,” Yejun (Janet) He, Ph.D., program director at NIH’s National Institute of Neurological Disorders and Stroke (NINDS).

Keyword: Consciousness
Link ID: 21711 - Posted: 12.19.2015

Megan Scudellari In 1997, physicians in southwest Korea began to offer ultrasound screening for early detection of thyroid cancer. News of the programme spread, and soon physicians around the region began to offer the service. Eventually it went nationwide, piggybacking on a government initiative to screen for other cancers. Hundreds of thousands took the test for just US$30–50. LISTEN James Harkin, a researcher for the British TV trivia show QI, talks to Adam Levy about how he finds facts and myths for the show — and then runs a mini-quiz to see whether the Podcast team can discern science fact from science fiction 00:00 Across the country, detection of thyroid cancer soared, from 5 cases per 100,000 people in 1999 to 70 per 100,000 in 2011. Two-thirds of those diagnosed had their thyroid glands removed and were placed on lifelong drug regimens, both of which carry risks. Such a costly and extensive public-health programme might be expected to save lives. But this one did not. Thyroid cancer is now the most common type of cancer diagnosed in South Korea, but the number of people who die from it has remained exactly the same — about 1 per 100,000. Even when some physicians in Korea realized this, and suggested that thyroid screening be stopped in 2014, the Korean Thyroid Association, a professional society of endocrinologists and thyroid surgeons, argued that screening and treatment were basic human rights. © 2015 Nature Publishing Group,

Keyword: Learning & Memory; Evolution
Link ID: 21708 - Posted: 12.16.2015

Parrots can dance and talk, and now apparently they can use and share grinding tools. They were filmed using pebbles for grinding, thought to be a uniquely human activity – one that allowed our civilisations to extract more nutrition from cereal-based foods. Megan Lambert from the University of York, UK, and her colleagues were studying greater vasa parrots (Coracopsis vasa) in an aviary when they noticed some of the birds scraping shells in their enclosure with pebbles and date pips. “We were surprised,” says Lambert. “Using tools [to grind] seashells is something never seen before in animals.” Afterwards, the birds would lick the powder from the tool. Some of the parrots even passed tools to each other, which is rarely seen in animals. This behaviour was exclusively male to female. Lambert and her team, who watched the parrots for six months, noticed that the shell-scraping was more frequent before their breeding season. Since seashells contain calcium, which is critical for females before egg-laying, they suspect that the parrots could be manufacturing their own calcium supplements, as the mineral is probably better absorbed in powder form. Greater vasa parrots are native to Madagascar and have breeding and social systems unique among parrots. For example, two or more males have an exclusive sexual relationship with two or more females, and they are unusually tolerant of their group members. The reproductive ritual of sharing tools and grinding could be yet another one of their quirks. © Copyright Reed Business Information Ltd.

Keyword: Intelligence; Evolution
Link ID: 21707 - Posted: 12.16.2015

Human memory is about to get supercharged. A memory prosthesis being trialled next year could not only restore long-term recall but may eventually be used to upload new skills directly to the brain – just like in the film The Matrix. The first trials will involve people with epilepsy. Seizures can sometimes damage the hippocampus, causing the brain to lose its ability to form long-term memories. To repair this ability, Theodore Berger at the University of Southern California and his colleagues used electrodes already implanted in people’s brains as part of epilepsy treatment to record electrical activity associated with memory. The team then developed an algorithm that could predict the neural activity thought to occur when a short-term memory becomes a long-term memory, as it passes through the hippocampus. Early next year, Berger’s team will use this algorithm to instruct the electrodes to predict and then mimic the activity that should occur when long-term memories are formed. “Hopefully, it will repair their long-term memory,” says Berger. Previous studies using animals suggest that the prosthesis might even give people a better memory than they could expect naturally. A similar approach could eventually be used to implant new memories into the brain. Berger’s team recorded brain activity in a rat that had been trained to perform a specific task. The memory prosthesis then replicated that activity in a rat that hadn’t been trained. The second rat was able to learn the task much faster than the first rat – as if it already had some memory of the task. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory; Robotics
Link ID: 21705 - Posted: 12.16.2015

Tina Hesman Saey SAN DIEGO — Friendly ghosts help muscles heal after injury. Connective tissue sheaths that bundle muscle cells together leave behind hollow fibers when muscles are injured, Micah Webster of the Carnegie Institution for Science in Baltimore and colleagues discovered. Muscle-repairing stem cells build new tissue from inside those empty tunnels, known as ghost fibers, Webster reported December 13 at the annual meeting of the American Society for Cell Biology. Researchers previously knew that stem cells can heal muscle, but how stem cells integrate new cells into muscle fibers has been a mystery. Webster and colleagues used a special microscopy technique to watch stem cells in live mice as the cells fixed muscles damaged by snake venom. Stem cells from undamaged parts of the muscle fiber crawled back and forth through the ghostly part of the fibers and spaced themselves out evenly. Stem cells replicated themselves to reconstruct each muscle fiber inside its ghostly shell the researchers found. Stem cells didn’t move from one ghost fiber to another. The finding suggests that researchers will need to create artificial ghost fibers to repair injuries in which chunks of muscles are lost, such as in soldiers hit by explosives, Webster said. The researchers also reported the results online December 10 in Cell Stem Cell. M.T. Webster et al. Intravital imaging reveals ghost fibers as architectural units guiding muscle progenitors. Annual meeting of the American Society for Cell Biology, San Diego, December 13, 2015. M.T. Webster et al. Intravital imaging reveals ghost fibers as architectural units guiding myogenic progenitors during regeneration. Cell Stem Cell. Published online December 10, 2015. doi: 10.1016/j.stem.2015.11.005 © Society for Science & the Public 2000 - 2015

Keyword: Muscles
Link ID: 21704 - Posted: 12.16.2015

By David Shultz As the Rolling Stones, Revlon, and Angelina Jolie can attest, not many body parts are more sexualized than the lips. A new study published online today in Royal Society Open Science, suggests that we’re not the only primates that feel this way. Black-and-white snub-nosed monkeys (Rhinopithecus bieti, pictured) have a strict social hierarchy in which a few, older males mate with multiple females, while the younger males form bachelor groups and bide their time. The males’ lips naturally redden with age, but the story seems a little more complicated than that: A series of photographs taken over multiple months shows that mating males’ lips redden during the mating season, whereas the bachelor males’ become paler. Scientists still aren’t sure why the animals’ lips seem to correspond with their social rank, but one idea is that females prefer the redder shades when choosing a mate, similar to how a female peacock chooses the male with the most elaborate tail. Another explanation could be that the males are using lip color as a preemptive indicator of their status in order to minimize conflict: Paler lips could make bachelors appear less threatening, allowing the mating males to focus their aggression on other red-lipped competitors. Both mechanisms could also be acting simultaneously, the authors say. © 2015 American Association for the Advancement of Science.

Keyword: Sexual Behavior
Link ID: 21703 - Posted: 12.16.2015

By Darold A. Treffert The headlines read “New study suggests autism can be outgrown”, or “outgrowing autism: a doctor’s surprise and wonder.” The stories are based on studies reporting that 7-9% of children with a documented early autistic syndrome disorder (ASD) have no symptoms of the disorder on follow-up later in childhood or adolescence. That is good news. The question is how to account for it. Is it possible to simply “outgrow” autism? Was the initial diagnosis wrong? Did some interventions work? Or might there be other explanations for this welcome news? "In an earlier column titled “Oops. When “autism” isn’t autistic disorder,” I outlined three types of hyperlexia, or precocious reading ability, which is sometimes an element of a diagnosis of ASD. Type 1 are neurotypical children who simply read way ahead of their chronological age. Listening to a 4 year old reading books to his or her nursery school classmates is a startling experience. Type 2 are children in which intense fascination with letters and numbers, along with early reading and remarkable memory represent ‘splinter skills’ as a part of autistic syndrome disorder (ASD) Type 3 are children who likewise show intense fascination and preoccupation with numbers and letters very early, along with precocious reading skills and remarkable memory. They do have “autistic-like” symptoms or behaviors but those disappear over time as the child gets older. The outcome in these children is much more positive than those with ASD to their benefit and the great relief of their parents. Following the “Oops” article I received numerous reports from parents who identified with hyperlexia 3. “You just described my child,” the puzzled, and relieved parents would write as they read the case examples in my Wisconsin Medical Journal article in December, 2011. © 2015 Scientific American

Keyword: Autism
Link ID: 21689 - Posted: 12.10.2015

Ian Sample Science editor Scientists have discovered a chemical that destroys toxic plaques which build up in the brain in the early stages of Alzheimer’s disease. Preliminary tests found that when added to drinking water, the compound cleared amyloid beta plaques from the brains of mice with Alzheimer’s-like symptoms, and restored their cognitive function to normal. The work is at a very early stage, but raises hopes for drugs that can prevent the accumulation of amyloid plaques and potentially halt the progression of the disease. Amyloid plaques are one of the first hallmarks of Alzheimer’s disease and are thought to contribute to neurodegeneration by killing off brain cells. Researchers in Korea discovered the chemical, EPPS, while screening a variety of molecules for their effects on amyloid plaques. In the latest study, they added the substance to the drinking water of mice that had symptoms of Alzheimer’s disease. They found that administering EPPS for a week improved how well mice performed on maze tests, and cleared amyloid plaques from the animals’ brains. “Our findings clearly support the view that aggregated amyloid-beta is the pathological culprit of Alzheimer’s disease,” said YoungSoo Kim, who led the team at the Korea Institute of Science and Technology in Seoul. The study used mice that had amyloid plaques injected into their brains. The animals suffered cognitive impairments as a result, but they did not develop the kind of widespread brain damage seen in Alzheimer’s patients which would not be reversed by removing amyloid plaques. © 2015 Guardian News and Media Limited

Keyword: Alzheimers
Link ID: 21685 - Posted: 12.09.2015

By Michael M. Torrice, We learn from experience: It sounds like a trite sentiment posted by a friend on Facebook, but neuroscientists would agree. Our interactions with the world around us strengthen and weaken the connections between our neurons, a process that neuroscientists consider to be the cellular mechanism of learning. Now researchers report that boosting signaling of a certain receptor in the brain with a small molecule can enhance these cellular changes and improve learning in people. The findings could lead to new treatments for patients with disorders associated with deficits in learning, such as Alzheimer’s disease and schizophrenia. Through decades of research on how synapses change in animal brains, scientists have found that the N-methyl-d-aspartate receptor (NMDAR) plays a critical role in strengthening synapses during learning. Compounds that increase NMDAR signaling can drive such changes and, as a result, help animals learn new tasks. Robert F. Asarnow at UCLA and colleagues wanted to test whether one such compound, d-cycloserine, would act similarly in people. But neuroscientists measure synapse changes in animals by sticking electrodes into slices of brain tissue to record electrical signals. “Obviously, we don’t do that to our friends,” Asarnow says. So his team used electroencephalography (EEG) to record electrical activity through electrodes stuck to the scalps of its subjects. The team monitored this activity as the subjects watched a certain pattern flash on a screen at high frequency for a couple minutes. Afterward, the subjects showed a spike in EEG activity in their visual cortex when they viewed the pattern at a later time. This suggested a population of neurons had wired themselves together by strengthening their synapses. © 2015 Scientific American

Keyword: Learning & Memory
Link ID: 21684 - Posted: 12.09.2015

By John Horgan How does matter make mind? More specifically, how does a physical object generate subjective experiences like those you are immersed in as you read this sentence? How does stuff become conscious? This is called the mind-body problem, or, by philosopher David Chalmers, the “hard problem.” I expressed doubt that the hard problem can be solved--a position called mysterianism--in The End of Science. I argue in a new edition that my pessimism has been justified by the recent popularity of panpsychism. This ancient doctrine holds that consciousness is a property not just of brains but of all matter, like my table and coffee mug. Panpsychism strikes me as self-evidently foolish, but non-foolish people—notably Chalmers and neuroscientist Christof Koch—are taking it seriously. How can that be? What’s compelling their interest? Have I dismissed panpsychism too hastily? These questions lured me to a two-day workshop on integrated information theory at New York University last month. Conceived by neuroscientist Guilio Tononi (who trained under the late, great Gerald Edelman), IIT is an extremely ambitious theory of consciousness. It applies to all forms of matter, not just brains, and it implies that panpsychism might be true. Koch and others are taking panpsychism seriously because they take IIT seriously. © 2015 Scientific American

Keyword: Consciousness
Link ID: 21673 - Posted: 12.03.2015

Tina Hesman Saey Genies are said to have the power to grant three wishes. But genies recently released from laboratory flasks promise to fulfill nearly any wish a biologist can dream up. End the scourge of insect-borne diseases? Check. Inoculate endangered amphibians against killer fungi? Yes. Pluck invasive species from environments where they don’t belong? As you wish. These genies aren’t magical; they are research tools known as gene drives — clever bits of engineered DNA designed to propel themselves into the DNA of a pesky or troubled organism. A gene drive is a targeted contagion intended to spread within species, forever altering the offspring. Gene drive enthusiasts say these genies could wipe out malaria, saving more than half a million lives each year. Invasive species, herbicide-resistant weeds and pesticide-resistant bugs could be driven out of existence. Animals that carry harmful viruses could be immunized with ease. Scientists have sought the power of gene drives for decades. But only with the emergence of a genetic tool called CRISPR/Cas9 — the bottle opener that unleashed the genie — has gene drive technology offered the prospect of providing a speedy means to end some of the world’s greatest health and ecological scourges. “Everything is possible with CRISPR,” says geneticist Hugo Bellen. “I’m not kidding.” © Society for Science & the Public 2000 - 2015.

Keyword: Genes & Behavior
Link ID: 21671 - Posted: 12.03.2015

You may have read that having a male brain will earn you more money. Or maybe that female brains are better at multitasking. But there is no such thing as a female or male brain, according to the first search for sex differences across the entire human brain. It reveals that most people have a mix of male and female brain features. And it also supports the idea that gender is non-binary, and that gender classifications in many situations are meaningless. “This evidence that human brains cannot be categorised into two distinct classes is new, convincing, and somehow radical,” says Anelis Kaiser at the University of Bern, Switzerland. The idea that people have either a “female” or “male” brain is an old one, says Daphna Joel at Tel Aviv University in Israel. “The theory goes that once a fetus develops testicles, they secrete testosterone which masculinises the brain,” she says. “If that were true, there would be two types of brain.” To test the theory, Joel and her colleagues looked for differences in brain scans taken from 1400 people aged between 13 and 85. The team looked for variations in the size of brain regions as well as the connections between them. In total, the group identified 29 brain regions that generally seem to be different sizes in self-identified males and females. These include the hippocampus, which is involved in memory, and the inferior frontal gyrus, which is thought to play a role in risk aversion. When the group looked at each individual brain scan, however, they found that very few people had all of the brain features they might be expected to have, based on their sex. Across the sample, between 0 and 8 per cent of people had “all-male” or “all-female” brains, depending on the definition. “Most people are in the middle,” says Joel. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior
Link ID: 21670 - Posted: 12.01.2015

By Kelli Whitlock Burton Evolutionarily speaking, we are born to make babies. Our bodies—and brains—don’t fall apart until we come to the end of our child-bearing years. So why are grandmothers, who don’t reproduce and who contribute little to food production, still around and still mentally sound? A new study offers an intriguing genetic explanation. Scientists have proposed several explanations for why our species lives as long and as healthily as it does. One idea is that grandmothers help out with child rearing. A 1998 study found, for example, that a Hadza group of hunter-gatherers in Tanzania had more babies if grandmothers helped feed their newly-weaned young grandchildren. The researchers speculated this kind of care freed up young mothers to reproduce, and ensured that the caregiver grandmother’s genes were passed on to more young. They called their theory the “grandmother hypothesis.” But grandmothers need to have all their wits about them to help out in this way, and the new study may explain how this happens. Physician-scientist Ajit Varki and evolutionary biologist Pascal Gagneux of the University of California, San Diego, arrived at the findings accidentally. The pair was studying a gene that helps control the body’s inflammatory and immune response to injury or infection. Previous studies have linked two forms of the gene—CD33—to Alzheimer’s disease. While one CD33 variant, or allele, predisposes a person to the disease, the other appears to protect against it by preventing the formation of protein clumps in the brain. © 2015 American Association for the Advancement of Science.

Keyword: Alzheimers; Genes & Behavior
Link ID: 21669 - Posted: 12.01.2015

By Diana Kwon The human brain is unique: Our remarkable cognitive capacity has allowed us to invent the wheel, build the pyramids and land on the moon. In fact, scientists sometimes refer to the human brain as the “crowning achievement of evolution.” But what, exactly, makes our brains so special? Some leading arguments have been that our brains have more neurons and expend more energy than would be expected for our size, and that our cerebral cortex, which is responsible for higher cognition, is disproportionately large—accounting for over 80 percent of our total brain mass. Suzana Herculano-Houzel, a neuroscientist at the Institute of Biomedical Science in Rio de Janeiro, debunked these well-established beliefs in recent years when she discovered a novel way of counting neurons—dissolving brains into a homogenous mixture, or “brain soup.” Using this technique she found the number of neurons relative to brain size to be consistent with other primates, and that the cerebral cortex, the region responsible for higher cognition, only holds around 20 percent of all our brain’s neurons, a similar proportion found in other mammals. In light of these findings, she argues that the human brain is actually just a linearly scaled-up primate brain that grew in size as we started to consume more calories, thanks to the advent of cooked food. Other researchers have found that traits once believed to belong solely to humans also exist in other members of the animal kingdom. Monkeys have a sense of fairness. Chimps engage in war. Rats show altruism and exhibit empathy. In a study published last week in Nature Communications, neuroscientist Christopher Petkov and his group at Newcastle University found that macaques and humans share brain areas responsible for processing the basic structures of language. © 2015 Scientific American

Keyword: Evolution; Brain imaging
Link ID: 21668 - Posted: 12.01.2015