Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior

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


Links 1 - 20 of 1223

Andy Tay The mammalian brain consists of billions of neurons wired together in various circuits, each one involved in specific physiological functions. To better understand how these different neurons and circuits are associated with mental activities and diseases, researchers are reconstructing detailed, three-dimensional maps of neural networks. However, 3-D imaging of the mammalian brain is challenging. Light scatters as it travels through layers of tissue, dispersed by a variety of molecules such as water, lipids, and proteins. This reduces image resolution. One way to improve resolution is to reduce the scattering. Researchers achieve this by first removing water and lipids from tissue. Next, chemicals are introduced that have a refractive index—a measure of how much the molecules bend light that passes through them—in the range of that of proteins. Establishing near-homogenous refractive indices in the molecules that populate the tissue environment allows light rays to converge to improve image resolution. This is the working principle of most tissue clearing methods, which have been used successfully for decades on hard tissues like bone. Researchers have performed brain tissue clearing with limited success, as the chemicals available were too harsh on delicate neural tissues. In 2013, Karl Deisseroth and his team at Stanford University revolutionized the approach with a hydrogel-based technique called CLARITY. This technique enabled researchers to label neurons in mouse neural tissue with fluorescent markers and then to image an entire mouse brain without sectioning it, while preserving the fluorescence signals. © 1986–2019 The Scientist.

Keyword: Brain imaging
Link ID: 26718 - Posted: 10.18.2019

Mengying Zhang While many people love colorful photos of landscapes, flowers or rainbows, some biomedical researchers treasure vivid images on a much smaller scale – as tiny as one-thousandth the width of a human hair. To study the micro world and help advance medical knowledge and treatments, these scientists use fluorescent nano-sized particles. Quantum dots are one type of nanoparticle, more commonly known for their use in TV screens. They’re super tiny crystals that can transport electrons. When UV light hits these semiconducting particles, they can emit light of various colors. One nanometer is one-millionth of a millimeter. RNGS Reuters/Nanosys That fluorescence allows scientists to use them to study hidden or otherwise cryptic parts of cells, organs and other structures. I’m part of a group of nanotechnology and neuroscience researchers at the University of Washington investigating how quantum dots behave in the brain. Common brain diseases are estimated to cost the U.S. nearly US$800 billion annually. These diseases – including Alzheimer’s disease and neurodevelopmental disorders – are hard to diagnose or treat. Nanoscale tools, such as quantum dots, that can capture the nuance in complicated cell activities hold promise as brain-imaging tools or drug delivery carriers for the brain. But because there are many reasons to be concerned about their use in medicine, mainly related to health and safety, it’s important to figure out more about how they work in biological systems. © 2010–2019, The Conversation US, Inc.

Keyword: Brain imaging
Link ID: 26708 - Posted: 10.16.2019

Jyoti Madhusoodanan Douglas Storace still has the dollar bill that he triumphantly taped above his laboratory bench seven years ago, a trophy from a successful wager. His postdoctoral mentor, Larry Cohen at Yale University in New Haven, Connecticut, bet that Storace couldn’t express a protein sensor of voltage changes in mice back in September 2012. Storace won. The bill is a handy reminder that the experiments he aims to try in his new lab can work. And it’s a testament to just how tricky it is to correctly express these sensors and track their signals. Storace, now an assistant professor at Florida State University in Tallahassee, plans to use these sensors, known as genetically encoded voltage indicators (GEVIs), to study how neurons in the olfactory bulb sense and react to smells. GEVIs are voltage-sensitive, fluorescent proteins that change colour when a neuron fires or receives a signal. Because GEVIs can be targeted to individual cells and directly indicate a cell’s electrical signals, researchers consider them to be the ideal probes for studying neurons. But they have proved frustratingly difficult to use. “Being able to visualize voltage changes in a cell has always been the dream,” says neuroscientist Bradley Baker at the Korea Institute of Science and Technology in Seoul. “But probes that looked great often didn’t behave in ways that were useful.” Early GEVIs disappointed on several levels. They were bright when a cell was resting and dimmed when the cell fired an action potential, producing signals that were tough to distinguish from the background. And they failed to concentrate in the nerve-cell membranes, where they function. But researchers are beginning to solve these issues. Some are turning to advanced fluorescent proteins or chemical dyes for better signals; others are using directed evolution and high-throughput screens to make GEVIs more sensitive to voltage changes. Meanwhile, biologists are putting these molecules through their paces. GEVIs, says neuroscientist Katalin Toth at Laval University in Quebec City, Canada, are not yet widely used, but they’re getting there. “They are becoming brighter and faster — and growing in popularity,” she says. “I think this is the dawn of GEVIs.” © 2019 Springer Nature Limited

Keyword: Brain imaging
Link ID: 26703 - Posted: 10.15.2019

By Laura Sanders Survey any office, and you’ll see pens tapping, heels bouncing and hair being twiddled. But jittery humans aren’t alone. Mice also fidget while they work. What’s more, this seemingly useless motion has a profound and widespread effect on mice’s brain activity, neuroscientist Anne Churchland of Cold Spring Harbor Laboratory in New York and colleagues report September 24 in Nature Neuroscience. Scientists don’t yet know what this brain activity means, but one possibility is that body motion may actually shape thinking. Researchers trained some mice to lick a spout corresponding to an area where a click or a flash of light originated. To start their task, mice grabbed a handle and waited for the signal. As the mice focused on their jobs, researchers used several different methods to eavesdrop on nerve cell behavior in the animals’ brains. All the while, video cameras and a sensor embedded on a platform under the mice picked up every move the rodents made — and there were a lot. Mice wiggled their noses, flicked their whiskers and fiddled their hind paws while concentrating on finding the sound or light, the team found. Those fidgets showed up in nerve cell activity. When a whisker moved, for instance, nerve cells involved in moving and sensing sprang into action. Fidgets predicted a big chunk of neural behavior, mathematical models suggested. Mice’s fidgets even had stronger effects on brain activity than did the task at hand, the researchers report. © Society for Science & the Public 2000–2019

Keyword: Brain imaging
Link ID: 26653 - Posted: 09.28.2019

Alison Abbott A prominent German neuroscientist committed scientific misconduct in research in which he claimed to have developed a brain-monitoring technique able to read certain thoughts of paralysed people, Germany’s main research agency has found. The DFG’s investigation into Niels Birbaumer’s high-profile work found that data in two papers were incomplete and that the scientific analysis was flawed — although it did not comment on whether the approach was valid. In a 19 September statement, the agency, which funded some of the work, said it was imposing some of its most severe sanctions to Birbaumer, who has positions at the University of Tübingen in Germany and the Wyss Center for Bio and Neuroengineering in Geneva, Switzerland. The DFG has banned Birbaumer from applying for its grants and from serving as a DFG evaluator for five years. The agency has also recommended the retraction of the two papers1,2 published in PLoS Biology, and says that it will ask him to return the grant money that he used to generate the data underpinning the papers. “The DFG has found scientific misconduct on my part and has imposed sanctions. I must therefore accept that I was unable to refute the allegations made against me,” Birbaumer said in a statement e-mailed to Nature in response to the DFG’s findings. In a subsequent phone conversation with Nature, Birbaumer added that he could not comment further on the findings because the DFG has not yet provided him with specific details on the reasoning behind the decisions. Birbaumer says he stands by his studies, which he says, “show that it is possible to communicate with patients who are completely paralysed, through computer-based analysis of blood flow and brain currents”. © 2019 Springer Nature Limited

Keyword: Consciousness; Brain imaging
Link ID: 26636 - Posted: 09.23.2019

Heidi Ledford Tumour cells can plug into — and feed off — the brain’s complex network of neurons, according to a trio of studies. This nefarious ability could explain the mysterious behaviour of certain tumours, and point to new ways of treating cancer. The studies1,2,3, published on 18 September in Nature, describe this startling capability in brain cancers called gliomas, as well as in some breast cancers that spread to the brain. The findings bolster a growing realization among doctors and scientists that the nervous system plays an important role in the growth of cancers, says Michelle Monje, a paediatric neuro-oncologist at Stanford University in California and lead author of one of the studies1. Even so, finding cancer cells that behave like neurons was a surprise. “It’s unsettling,” Monje says. “We don’t think of cancer as forming an electrically active tissue like the brain.” Feeding off the brain Frank Winkler, a neurologist at Heidelberg University in Germany and a lead author on another of the Nature studies2, stumbled on the phenomenon in 2014 while studying communication networks established by cells in some brain tumours. He and his team discovered synapses, structures that neurons use to communicate with one another, in the tumours. It was “crazy stuff”, Winkler says. “Our first reaction was, ‘This is just difficult to believe.’” The researchers assumed that the tumour synapses would be a random occurrence. But as Winkler and his colleagues report in their latest study, they found synapses in glioma samples taken from cancer cells grown in culture, human glioma tumours transplanted into mice and glioma samples taken from ten people.

Keyword: Glia
Link ID: 26625 - Posted: 09.19.2019

By Kim Tingley Men have a far greater appetite for sex and are more attracted to pornography than women are. This is the timeworn stereotype that science has long reinforced. Alfred Kinsey, America’s first prominent sexologist, published in the late 1940s and early 1950s his survey results confirming that men are aroused more easily and often by sexual imagery than women. It made sense, evolutionary psychologists theorized, that women’s erotic pleasure might be tempered by the potential burdens of pregnancy, birth and child rearing — that they would require a deeper emotional connection with a partner to feel turned on than men, whose primal urge is simply procreation. Modern statistics showing that men are still the dominant consumers of online porn seem to support this thinking, as does the fact that men are more prone to hypersexuality, whereas a lack of desire and anorgasmia are more prevalent in women. So it was somewhat surprising when a paper in the prestigious journal P.N.A.S. reported in July that what happens in the brains of female study subjects when they look at sexual imagery is pretty much the same as what happens in the brains of their male counterparts. The researchers, led by Hamid Noori at the Max Planck Institute for Biological Cybernetics in Germany, weren’t initially interested in exploring sexual behavior. They were trying to find ways to standardize experiments that use functional magnetic resonance imaging (fM.R.I.) to observe how the brain responds to visual stimuli. In order to do that, they needed to compare past studies that used similar methods but returned diverse results. They happened to choose studies in which male and female volunteers looked at sexual imagery, both because doing so tends to generate strong signals in the brain, which would make findings easier to analyze, and because this sort of research has long produced “inconsistent and even contradictory” results, as they note in their paper. Identifying the reasons for such discrepancies might help researchers design better experiments. © 2019 The New York Times Company

Keyword: Sexual Behavior; Brain imaging
Link ID: 26622 - Posted: 09.18.2019

By Laura Sanders Two artists who paint with their toes have unusual neural footprints in their brains. Individual toes each take over discrete territory, creating a well-organized “toe map,” researchers report September 10 in Cell Reports. Similar brain organization isn’t thought to exist in people with typical toe dexterity. So finding these specialized maps brings scientists closer to understanding how the human brain senses the body, even when body designs differ (SN: 6/12/19). “Sometimes, having the unusual case — even the very rare one — might give you important insight into how things work,” says neuroscientist Denis Schluppeck of the University of Nottingham in England, who was not involved in the study. The skills of the two artists included in the study are certainly rare. Both were born without arms due to the drug thalidomide, formerly used to treat morning sickness in pregnant women. As a result, both men rely heavily on their feet, which possess the dexterity to eat with cutlery, write and use computers. The brain carries a map of areas that handle sensations from different body parts; sensitive fingers and lips, for example, have big corresponding areas. But so far, scientists haven’t had much luck in pinpointing areas of the human brain that respond to individual toes (although toe regions have been found in the brains of nonhuman primates). But because these men use their feet in unusually skilled ways, researchers wondered if their brains might represent toes a bit differently. The two artists, along with nine other people with no special foot abilities, underwent functional MRI scans while an experimenter gently touched each toe. For many people, the brain areas that correspond to individual toes aren’t discrete, says neuroscientist Daan Wesselink of University College London. But in the foot artists’ brains, “we found very distinct locations for each of their toes.” When each toe was touched, a patch of brain became active, linking neighboring toes to similarly neighboring areas of the brain. © Society for Science & the Public 2000–2019

Keyword: Pain & Touch; Brain imaging
Link ID: 26601 - Posted: 09.11.2019

By Emily Oster At some point or another, most books about the brain come back to the story of Phineas Gage. Gage was a railroad worker in the 19th century. In an unfortunate 1848 accident, a large steel spike was driven through his eye and out the other side of his head, taking some of his brain with him (this is the point in the story where my 8-year-old told me to please stop telling it). Amazingly, Gage survived the accident with much of his faculties intact. What did change was his personality, which, by many reports, became more aggressive and belligerent. Gage’s doctor wrote up his case, arguing that it suggested “civilized conduct” was localized in a particular part of the brain — specifically, the part he had lost. Science was off in search of where in the brain various skills were kept, with the idea that the brain was a kind of map, with little areas for, say, walking or talking or hearing or smelling. This proceeded, albeit slowly; for a while, there wasn’t much of a way to study this other than by looking at people with traumatic brain injuries. So it’s understandable that the development of technologies to study intact brains caused a lot of excitement. Generating the most discussion in recent years has been functional magnetic resonance imaging (or fMRI), which allows researchers to measure oxygen flow to the brain and identify which parts activate in response to varying stimuli. These technologies have not always lived up to the hype. The mechanics and statistics of processing fMRI imaging data have turned out to be far more complex than initially imagined. As a result there were many false claims made about which parts of the brain “controlled” different aspects of behavior or actions. The best, or at least funniest, example of this was a paper that showed how cutting-edge statistical analysis of fMRI made it possible to identify parts of the brain that responded differently to happy or sad faces. Sounds good, until you learn that the subject for this experiment was a dead fish. © 2019 The New York Times Company

Keyword: Sexual Behavior; Brain imaging
Link ID: 26594 - Posted: 09.10.2019

By Eryn Brown, On March 30, 1981, 25-year-old John W. Hinckley Jr. shot President Ronald Reagan and three other people. The following year, he went on trial for his crimes. Defense attorneys argued that Hinckley was insane, and they pointed to a trove of evidence to back their claim. Their client had a history of behavioral problems. He was obsessed with the actress Jodie Foster, and devised a plan to assassinate a president to impress her. He hounded Jimmy Carter. Then he targeted Reagan. In a controversial courtroom twist, Hinckley’s defense team also introduced scientific evidence: a computerized axial tomography (CAT) scan that suggested their client had a “shrunken,” or atrophied, brain. Initially, the judge didn’t want to allow it. The scan didn’t prove that Hinckley had schizophrenia, experts said—but this sort of brain atrophy was more common among schizophrenics than among the general population. It helped convince the jury to find Hinckley not responsible by reason of insanity. Nearly 40 years later, the neuroscience that influenced Hinckley’s trial has advanced by leaps and bounds—particularly because of improvements in magnetic resonance imaging (MRI) and the invention of functional magnetic resonance imaging (fMRI), which lets scientists look at blood flows and oxygenation in the brain without hurting it. Today neuroscientists can see what happens in the brain when a subject recognizes a loved one, experiences failure, or feels pain. Despite this explosion in neuroscience knowledge, and notwithstanding Hinckley’s successful defense, “neurolaw” hasn’t had a tremendous impact on the courts—yet. But it is coming. Attorneys working civil cases introduce brain imaging ever more routinely to argue that a client has or has not been injured. Criminal attorneys, too, sometimes argue that a brain condition mitigates a client’s responsibility. Lawyers and judges are participating in continuing education programs to learn about brain anatomy and what MRIs and EEGs and all those other brain tests actually show. © 2019 Scientific American

Keyword: Brain imaging
Link ID: 26587 - Posted: 09.09.2019

/ By Hope Reese In her new book “Gender and Our Brains,” cognitive neuroimaging professor Gina Rippon explains that brains aren’t gendered, but research can be. The differences among women as a group, or men as a group, are greater than the differences between men and women, Rippon says. Rippon sifts through centuries of research into supposed differences in areas such as behavior, skills, and personality, and shows that external factors like gender stereotypes and real-world experiences are the likely cause of any detectable differences in mental processing. And she demonstrates that the differences among women as a group, or among men as a group, are much greater than the differences between men and women. She cites a 2015 study looking at 1,400 brain scans as an example. Comparing 160 brain structures in the scans — identifying areas that were, on average, larger in men or in women — researchers could not find any scans that had all “male” traits, or all “female” traits — physical attributes such as weight or tissue thickness. “The images were, literally, of a mosaic,” she says. “We’re trying to force a difference into data that doesn’t exist.” Rippon teaches cognitive neuroimaging — the study of behavior through brain images — at Aston University in England. For this installment of the Undark Five, I spoke with her about how neuroimages are misinterpreted and whether PMS is real, among other topics. Here is our conversation, edited for length and clarity. Undark: Scientists have been trying to find differences in the brains of men and women for years. What are some examples of how the cherry-picking approach is problematic? Gina Rippon: It’s what I call the “hunt the differences” agenda, which started about 200 years ago when scientists were starting to understand the importance of the brain in explaining human behavior and human ability. Copyright 2019 Undark

Keyword: Sexual Behavior; Brain imaging
Link ID: 26584 - Posted: 09.07.2019

By Carolyn Wilke In learning to read, squiggles and lines transform into letters or characters that carry meaning and conjure sounds. A trio of cognitive neuroscientists has now mapped where that journey plays out inside the brain. As readers associate symbols with pronunciation and part of a word, a pecking order of brain areas processes the information, the researchers report August 19 in the Proceedings of the National Academy of Sciences. The finding unveils some of the mystery behind how the brain learns to tie visual cues with language (SN Online: 4/27/16). “We didn’t evolve to read,” says Jo Taylor, who is now at University College London but worked on the study while at Aston University in Birmingham, England. “So we don’t [start with] a bit of the brain that does reading.” Taylor — along with Kathy Rastle at Royal Holloway University of London in Egham and Matthew Davis at the University of Cambridge — zoomed in on a region at the back and bottom of the brain, called the ventral occipitotemporal cortex, that is associated with reading. Over two weeks, the scientists taught made-up words written in two unfamiliar, archaic scripts to 24 native English–speaking adults. The words were assigned the meanings of common nouns, such as lemon or truck. Then the researchers used functional MRI scans to track which tiny chunks of brain in that region became active when participants were shown the words learned in training. © Society for Science & the Public 2000–2019

Keyword: Language; Brain imaging
Link ID: 26548 - Posted: 08.27.2019

/ By Lola Butcher Like all primary care physicians, Danielle Ofri sees a lot of aching backs. Low back pain is one of the top five reasons people visit the doctor, and based on extensive experience, Ofri knows how the conversations will go. Patients want relief from miserable pain, so they want an imaging study. “I want to see what’s going on — that’s what they say,” says Ofri, who treats patients at Bellevue Hospital in Manhattan. The easy thing to do is order a scan and send them home to wait for the results. The right thing to do, in the vast majority of cases, is to deliver the bad news: They need to wait for the pain to subside on its own, which may mean a few weeks of agony. In the meantime, if possible, it’s best to stay active and limit bed rest. An over-the-counter pain reliever might help. Unless certain symptoms point to a more serious problem, the physician shouldn’t order any imaging within the first six weeks of pain. On this last point, medical guidelines are remarkably clear and backed by studies demonstrating that routine imaging for low back pain does not improve one’s pain, function, or quality of life. The exams are not just a waste of time and money, physician groups say; unnecessary imaging may lead to problems that are much more serious than back pain. And yet, between 1995 and 2015, magnetic resonance imaging (MRI) and other high-tech scans for low back pain increased by 50 percent, according to a new systematic review published in the British Journal of Sports Medicine. According to a related analysis, up to 35 percent of the scans were inappropriate. Medical societies have launched campaigns to convince physicians and patients to forgo the unnecessary images, but to little avail. Copyright 2019 Undark

Keyword: Pain & Touch; Brain imaging
Link ID: 26540 - Posted: 08.26.2019

Jon Hamilton In mice, scientists have used a variety of drugs to treat brain disorders including murine versions of Alzheimer's disease, depression and schizophrenia. But in people, these same treatments usually fail. And now researchers are beginning to understand why. A detailed comparison of the cell types in mouse and human brain tissue found subtle but important differences that could affect the response to many drugs, a team reports Wednesday in the journal Nature. "If you want to develop a drug that targets a specific receptor in a specific disease, then these differences really matter," says Christof Koch, an author of the study and chief scientist and president of the Allen Institute for Brain Science in Seattle. One key difference involved genes that cause a cell to respond to the chemical messenger serotonin, says Ed Lein, a study author and investigator at the institute. "They're expressed in both mouse and human, but they're not in the same types of cells," Lein says. As a result, "serotonin would have a very different function when released into the cortex of the two species." That's potentially a big deal because antidepressants like Prozac act on the brain's serotonin system. So testing these drugs on mice could be misleading, Lein says. The comparison was possible because of new technology that allows scientists to quickly identify which of the hundreds of types of brain cells are present in a particular bit of brain tissue. © 2019 npr

Keyword: Brain imaging; Evolution
Link ID: 26530 - Posted: 08.22.2019

Nicola Davis A new organ involved in the sensation of pain has been discovered by scientists, raising hopes that it could lead to the development of new painkilling drugs. Researchers say they have discovered that the special cells that surround the pain-sensing nerve cells that extend into the outer layer of skin appear to be involved in sensing pain – a discovery that points to a new organ behind the feeling of “ouch!”. The scientists say the finding offers new insight into pain and could help answer longstanding conundrums. “The major question for us now is whether these cells are actually the cause for certain kinds of chronic pain disorders,” Prof Patrik Ernfors, a co-author of the research from the Karolinska Institute in Sweden, told the Guardian. Writing in the journal Science, the researchers reveal how they examined the nature of cells in the skin that, they say, have largely been overlooked. These are a type of Schwann cell, which wrap around and engulf nerve cells and help to keep them alive. The study has revealed these Schwann cells have an octopus-like shape. After examining tissues, the team found the body of the cells sits below the outer layer of the skin, but that the cells have long extensions that wrap around the ends of pain-sensing nerve cells that extend up into the epidermis, the outer layer of the skin. The scientists were surprised at the findings because it has long been believed that the endings of nerve cells in the epidermis were bare or unwrapped. “In the pain field, we talk about free nerve endings that are responsible for pain sensation. But actually they are not free,” Ernfors said. © 2019 Guardian News & Media Limited

Keyword: Pain & Touch; Glia
Link ID: 26507 - Posted: 08.16.2019

Laura Sanders The golf ball–sized chunk of brain is not cooperating. It’s thicker than usual, and bloodier. One side has a swath of tissue that looks, to my untrained eye, like gristle. Nick Dee, the neuroscientist charged with quickly cutting the chunk into neat pieces, confers with his colleagues. “We can trim off that ugliness on the side,” he says. The “ugliness” is the brain’s connective tissue called white matter. To produce useful slices for experiments, the brain tissue must be trimmed, superglued to a lipstick-sized base and then fed into a lab version of a deli slicer. But this difficult chunk isn’t cutting nicely. Dee and colleagues pull it off the base, trim it again and reglue. Half an hour earlier, this piece of neural tissue was tucked inside a 41-year-old woman’s head, on her left side, just above the ear. Surgeons removed the tissue to reach a deeper part of her brain thought to be causing severe seizures. Privacy rules prevent me from knowing much about her; I don’t know her name, much less her first memory, favorite meal or sense of humor. But within this piece of tissue, which the patient generously donated, are clues to how her brain — all of our brains, really — create the mind. Dee’s team is working fast because this piece of brain is alive. Some of the cells can still behave as if they are a part of a person’s brain, which means they hold enormous potential for scientists who want to understand how we remember, plan, behave and feel. After Dee and his team do their part, pieces of the woman’s brain will be whisked into the hands of eager scientists, where the cells will be photographed, zapped with electricity, relieved of their genetic material and even infected with viruses that make them glow green and red. © Society for Science & the Public 2000 - 2019

Keyword: Brain imaging; Evolution
Link ID: 26490 - Posted: 08.12.2019

By Paula Span Juli Engel was delighted when a neurologist recommended a PET scan to determine whether amyloid — the protein clumps associated with an increased risk of Alzheimer’s disease — was accumulating in her mother’s brain. “My internal response was, ‘Yay!’” said Ms. Engel, 65, a geriatric care manager in Austin, Tex., who has been making almost monthly trips to help her mother in Florida. “He’s using every tool to try to determine what’s going on.” Sue Engel, who’s 83 and lives in a retirement community in Leesburg, Fla., has been experiencing memory problems and other signs of cognitive decline for several years. Her daughter checked off the warning signs: her mother has been financially exploited, suffered an insurance scam, caused an auto accident. Medicare officials decided in 2013, shortly after PET (positron emission tomography) amyloid imaging became available, that they lacked evidence of its health benefits. So outside of research trials, Medicare doesn’t cover the scans’ substantial costs ($5,000 to $7,000, the Alzheimer’s Association says); private insurers don’t, either. Juli Engel thinks Medicare should reimburse for the scan, but “if necessary, we’ll pay for it out of pocket,” she said. Her mother already has an Alzheimer’s diagnosis and is taking a commonly prescribed dementia drug. So she probably doesn’t meet the criteria developed by the Alzheimer’s Association and nuclear medicine experts, which call for PET scans only in cases of unexplained or unusual symptoms and unclear diagnoses. But as evidence mounts that brain damage from Alzheimer’s begins years before people develop symptoms, worried patients and their families may start turning to PET scans to learn if they have this biomarker. © 2019 The New York Times Company

Keyword: Alzheimers; Brain imaging
Link ID: 26484 - Posted: 08.03.2019

Ian Sample Science editor Doctors have turned the brain signals for speech into written sentences in a research project that aims to transform how patients with severe disabilities communicate in the future. The breakthrough is the first to demonstrate how the intention to say specific words can be extracted from brain activity and converted into text rapidly enough to keep pace with natural conversation. In its current form, the brain-reading software works only for certain sentences it has been trained on, but scientists believe it is a stepping stone towards a more powerful system that can decode in real time the words a person intends to say. A neuroscientist explains: the need for ‘empathetic citizens’ - podcast Doctors at the University of California in San Francisco took on the challenge in the hope of creating a product that allows paralysed people to communicate more fluidly than using existing devices that pick up eye movements and muscle twitches to control a virtual keyboard. “To date there is no speech prosthetic system that allows users to have interactions on the rapid timescale of a human conversation,” said Edward Chang, a neurosurgeon and lead researcher on the study published in the journal Nature. The work, funded by Facebook, was possible thanks to three epilepsy patients who were about to have neurosurgery for their condition. Before their operations went ahead, all three had a small patch of tiny electrodes placed directly on the brain for at least a week to map the origins of their seizures. © 2019 Guardian News & Media Limited

Keyword: Brain imaging; Language
Link ID: 26472 - Posted: 07.31.2019

By Sarah White | Some five ounces of clear fluid fills the spaces between your brain and your skull. This brain juice, or cerebrospinal fluid, cushions against injury, supplies nutrients and clears away waste. Your body can make as much as a pint of fresh stuff every day to replace the old. But for 150 years, scientists have puzzled over how the used cerebrospinal fluid leaves the brain to make room for more. New research, published Wednesday in Nature, has finally deciphered this brain drain process. As a result, it’s also inching us closer to understanding Alzheimer’s and other neurodegenerative diseases. South Korean scientists, led by Gou Young Koh, completed the puzzle by studying our immune system’s superhighway, dubbed the lymphatic system. They were able to trace the cerebrospinal fluid’s one-directional path in mice, from its origin in the brain into lymph nodes in the neck. The key conduit? Lymphatic vessels at the bottom of the skull, in the brain’s outer layers. Before now, neuroscientists thought cerebrospinal fluid drained through lymphatic vessels on top of the brain or ones exiting through the nasal cavity. No one had managed to carefully examine the lymphatic vessels on the bottom of the brain because they’re so close to bones and delicate blood vessels. But by having a neurosurgeon on their team, the researchers could get close enough to identify what was so special about these bottom lymphatic vessels and see what makes them ideal for draining cerebrospinal fluid.

Keyword: Alzheimers
Link ID: 26455 - Posted: 07.27.2019

Abby Olena For years, scientists thought the brain lacked a lymphatic system, raising questions about how fluid, macromolecules, and immune cells escape the organ. In 2015, two studies in mice provided evidence that the brain does in fact have a traditional lymphatic system in the outermost layer of the meninges—the coverings that protect the brain and help keep its shape—but scientists hadn’t yet figured out the exact exit route cerebrospinal fluid (CSF) and molecules take. In a study published today (July 24) in Nature, researchers show that there is a hot spot of meningeal lymphatic vessels at the base of the rodent skull that is specialized to drain CSF and allow proteins and other large molecules to leave the brain. “What they showed very nicely is that the system of meningeal lymphatics is the drainage system of the CSF of the central nervous system,” says Jonathan Kipnis, a neuroscientist at the University of Virginia who did not participate in the new study, but coauthored the first 2015 study. “We’re just scratching really the surface of understanding what these vessels are doing.” “I’m actually quite relieved because when we published in 2015 . . . we got a lot of contrasting comments and some people were not convinced that the lymphatics really can be involved in cerebrospinal fluid drainage because there was a lot of literature telling otherwise,” Kari Alitalo of the University of Helsinki tells The Scientist. Alitalo coauthored the second 2015 paper describing the brain’s lymphatic system, but was not involved in the current study. © 1986–2019 The Scientist

Keyword: Brain imaging
Link ID: 26452 - Posted: 07.26.2019