Chapter 2. Neurophysiology: The Generation, Transmission, and Integration of Neural Signals

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Yongsoo Kim The brain plays an essential role in how people navigate the world by generating both thought and behavior. Despite being one of the most vital organs of life, it takes up only 2% of human body volume. How can something so small perform such complex tasks? Luckily, modern tools like brain mapping have allowed neuroscientists like me to answer this exact question. By mapping out how all the cell types in the brain are organized and examining how they communicate with one another, neuroscientists can better understand how brains normally work, and what happens when certain cell parts go missing or malfunction. The task of understanding the inner workings of the brain has fascinated both philosophers and scientists for centuries. Aristotle proposed that the brain is where spirit resides. Leonardo da Vinci drew anatomical depictions of the brain with wax embedding. And Santiago Ramón y Cajal, with his 1906 Nobel Prize-winning work on the cellular structure of the nervous system, made one of the first breakthroughs that led to modern neuroscience as we know it. Using a new way to visualize individual cells called Golgi staining, a method pioneered by Nobel co-winner Camillo Golgi, and microscopic examination of brain tissue, Cajal established the seminal neuron doctrine. This principle states that neurons, among the main types of brain cells, communicate with one another via the gaps between them called synapses. These findings launched a race to understand the cellular composition of the brain and how brain cells are connected to one another. Conversation US, Inc.

Keyword: Brain imaging
Link ID: 28085 - Posted: 11.20.2021

By David Dobbs Chronic pain is both one of the world’s most costly medical problems, affecting one in every five people, and one of the most mysterious. In the past two decades, however, discoveries about the crucial role played by glia — a set of nervous system cells once thought to be mere supports for neurons — have rewritten chronic pain science. These findings have given patients and doctors a hard-science explanation that chronic pain previously lacked. By doing so, this emerging science of chronic pain is beginning to influence care — not by creating new treatments, but by legitimizing chronic pain so that doctors take it more seriously. Although glia are scattered throughout the nervous system and take up almost half its space, they long received far less scientific attention than neurons, which do the majority of signaling in the brain and body. Some types of glia resemble neurons, with roughly starfish-like bodies, while others look like structures built with Erector sets, their long, straight structural parts joined at nodes. When first discovered in the mid-1800s, glia — from the Greek word for glue — were thought to be just connective tissue holding neurons together. Later they were rebranded as the nervous system’s janitorial staff, as they were found to feed neurons, clean up their waste and take out their dead. In the 1990s they were likened to secretarial staff when it was discovered they also help neurons communicate. Research over the past 20 years, however, has shown that glia don’t just support and respond to neuronal activity like pain signals — they often direct it, with enormous consequences for chronic pain. If you’re hearing this for the first time and you’re one of the billion-plus people on Earth who suffer from chronic pain (meaning pain lasting beyond three to six months that has no apparent cause or has become independent of the injury or illness that caused it), you might be tempted to say that your glia are botching their pain-management job. © 2021 The New York Times Company

Keyword: Pain & Touch; Glia
Link ID: 28075 - Posted: 11.13.2021

Kate Wild “The skull acts as a bastion of privacy; the brain is the last private part of ourselves,” Australian neurosurgeon Tom Oxley says from New York. Oxley is the CEO of Synchron, a neurotechnology company born in Melbourne that has successfully trialled hi-tech brain implants that allow people to send emails and texts purely by thought. In July this year, it became the first company in the world, ahead of competitors like Elon Musk’s Neuralink, to gain approval from the US Food and Drug Administration (FDA) to conduct clinical trials of brain computer interfaces (BCIs) in humans in the US. Synchron has already successfully fed electrodes into paralysed patients’ brains via their blood vessels. The electrodes record brain activity and feed the data wirelessly to a computer, where it is interpreted and used as a set of commands, allowing the patients to send emails and texts. BCIs, which allow a person to control a device via a connection between their brain and a computer, are seen as a gamechanger for people with certain disabilities. “No one can see inside your brain,” Oxley says. “It’s only our mouths and bodies moving that tells people what’s inside our brain … For people who can’t do that, it’s a horrific situation. What we’re doing is trying to help them get what’s inside their skull out. We are totally focused on solving medical problems.” BCIs are one of a range of developing technologies centred on the brain. Brain stimulation is another, which delivers targeted electrical pulses to the brain and is used to treat cognitive disorders. Others, like imaging techniques fMRI and EEG, can monitor the brain in real time. “The potential of neuroscience to improve our lives is almost unlimited,” says David Grant, a senior research fellow at the University of Melbourne. “However, the level of intrusion that would be needed to realise those benefits … is profound”. © 2021 Guardian News & Media Limited

Keyword: Brain imaging; Language
Link ID: 28070 - Posted: 11.09.2021

By Emily Anthes The brain of a fruit fly is the size of a poppy seed and about as easy to overlook. “Most people, I think, don’t even think of the fly as having a brain,” said Vivek Jayaraman, a neuroscientist at the Janelia Research Campus of the Howard Hughes Medical Institute in Virginia. “But, of course, flies lead quite rich lives.” Flies are capable of sophisticated behaviors, including navigating diverse landscapes, tussling with rivals and serenading potential mates. And their speck-size brains are tremendously complex, containing some 100,000 neurons and tens of millions of connections, or synapses, between them. Since 2014, a team of scientists at Janelia, in collaboration with researchers at Google, have been mapping these neurons and synapses in an effort to create a comprehensive wiring diagram, also known as a connectome, of the fruit fly brain. The work, which is continuing, is time-consuming and expensive, even with the help of state-of-the-art machine-learning algorithms. But the data they have released so far is stunning in its detail, composing an atlas of tens of thousands of gnarled neurons in many crucial areas of the fly brain. And now, in an enormous new paper, being published on Tuesday in the journal eLife, neuroscientists are beginning to show what they can do with it. By analyzing the connectome of just a small part of the fly brain — the central complex, which plays an important role in navigation — Dr. Jayaraman and his colleagues identified dozens of new neuron types and pinpointed neural circuits that appear to help flies make their way through the world. The work could ultimately help provide insight into how all kinds of animal brains, including our own, process a flood of sensory information and translate it into appropriate action. © 2021 The New York Times Company

Keyword: Brain imaging; Evolution
Link ID: 28057 - Posted: 10.30.2021

By Emily Anthes The brain of a fruit fly is the size of a poppy seed and about as easy to overlook. “Most people, I think, don’t even think of the fly as having a brain,” said Vivek Jayaraman, a neuroscientist at the Janelia Research Campus of the Howard Hughes Medical Institute in Virginia. “But, of course, flies lead quite rich lives.” Flies are capable of sophisticated behaviors, including navigating diverse landscapes, tussling with rivals and serenading potential mates. And their speck-size brains are tremendously complex, containing some 100,000 neurons and tens of millions of connections, or synapses, between them. Since 2014, a team of scientists at Janelia, in collaboration with researchers at Google, have been mapping these neurons and synapses in an effort to create a comprehensive wiring diagram, also known as a connectome, of the fruit fly brain. The work, which is continuing, is time-consuming and expensive, even with the help of state-of-the-art machine-learning algorithms. But the data they have released so far is stunning in its detail, composing an atlas of tens of thousands of gnarled neurons in many crucial areas of the fly brain. And now, in an enormous new paper, being published on Tuesday in the journal eLife, neuroscientists are beginning to show what they can do with it. By analyzing the connectome of just a small part of the fly brain — the central complex, which plays an important role in navigation — Dr. Jayaraman and his colleagues identified dozens of new neuron types and pinpointed neural circuits that appear to help flies make their way through the world. The work could ultimately help provide insight into how all kinds of animal brains, including our own, process a flood of sensory information and translate it into appropriate action. It is also a proof of principle for the young field of modern connectomics, which was built on the promise that constructing detailed diagrams of the brain’s wiring would pay scientific dividends. “It’s really extraordinary,” Dr. Clay Reid, a senior investigator at the Allen Institute for Brain Science in Seattle, said of the new paper. “I think anyone who looks at it will say connectomics is a tool that we need in neuroscience — full stop.” © 2021 The New York Times Company

Keyword: Brain imaging; Evolution
Link ID: 28055 - Posted: 10.27.2021

Barbara Jacquelyn Sahakian Christelle Langley Katrin Amunts While humans have walked on the Moon and sent probes all over the solar system, our understanding of our own brain is still severely lacking. We do not have complete knowledge of how brain structure, chemicals and connectivity interact to produce our thoughts and behaviours. But this isn’t from an absence of ambition. It is nearly eight years since the start of the Human Brain Project (HBP) in Europe, which aims to unravel the brain’s mysteries. After a difficult start, the project has made substantial discoveries and innovation, relevant for tackling clinical disorders, as well as technological advances – and it has two more years to go. It has also created EBRAINS, an open research infrastructure built on the scientific advances and tools developed by the project’s research teams, and making them available to the scientific community via a shared digital platform – a new achievement for collaborative research and instrumental in the achievements listed below. 1. Human brain atlas The project has created a unique multilevel human brain atlas based on several aspects of brain organisation, including its structure on the smallest of scales, its function and connectivity. This atlas provides a large number of tools to visualise data and work with them. Researchers can automatically extract data from the atlas using a special tool to run a simulation for modelling the brains of specific patients. This can help to inform clinicians of the optimal treatment option. © 2010–2021, The Conversation US, Inc.

Keyword: Brain imaging
Link ID: 28031 - Posted: 10.13.2021

Alison Abbott Imagine looking at Earth from space and being able to listen in on what individuals are saying to each other. That’s about how challenging it is to understand how the brain works. From the organ’s wrinkled surface, zoom in a million-fold and you’ll see a kaleidoscope of cells of different shapes and sizes, which branch off and reach out to each other. Zoom in a further 100,000 times and you’ll see the cells’ inner workings — the tiny structures in each one, the points of contact between them and the long-distance connections between brain areas. Scientists have made maps such as these for the worm1 and fly2 brains, and for tiny parts of the mouse3 and human4 brains. But those charts are just the start. To truly understand how the brain works, neuroscientists also need to know how each of the roughly 1,000 types of cell thought to exist in the brain speak to each other in their different electrical dialects. With that kind of complete, finely contoured map, they could really begin to explain the networks that drive how we think and behave. Such maps are emerging, including in a series of papers published this week that catalogue the cell types in the brain. Results are streaming in from government efforts to understand and stem the increasing burden of brain disorders in their ageing populations. These projects, launched over the past decade, aim to systematically chart the brain’s connections and catalogue its cell types and their physiological properties. It’s an onerous undertaking. “But knowing all the brain cell types, how they connect with each other and how they interact, will open up an entirely new set of therapies that we can’t even imagine today,” says Josh Gordon, director of the US National Institute of Mental Health (NIMH) in Bethesda, Maryland. © 2021 Springer Nature Limited

Keyword: Brain imaging; Development of the Brain
Link ID: 28029 - Posted: 10.09.2021

Amanda Heidt Qin Liu studies sneezing for a personal reason: her entire family suffers from seasonal allergies. “Until you experience something chronically, it is really hard to appreciate how disruptive it can be,” says Liu, a neuroscientist at Washington University in St. Louis. And given the role of sneezing in pathogen transmission, a better understanding of the molecular underpinnings of the phenomenon could one day help scientists mitigate or treat infectious diseases. When Liu first started looking into the mechanisms governing sneezing, she found that scientists know surprisingly little about how this process works. While prior research had identified a region in the brains of cats and humans that is active during sneezing, the exact pathways involved in turning a stimulus like pollen or spicy food into a sneeze remained unknown. To study sneezing in more detail, Liu and her team developed a new model by exposing mice to irritants such as histamine and capsaicin—a chemical in spicy peppers—and characterizing the physical properties of their resulting sneezes. Then, focusing on that previously discovered sneeze center, located in the brain’s ventromedial spinal trigeminal nucleus (SpV), Liu attempted to map the neural pathway. SNEEZE TRIGGER: When exposed to allergens such as histamine or chemical irritants such as capsaicin (1), sensory neurons in the noses of mice produce a peptide called neuromedin B (NMB). This signaling molecule binds to neurons in a region of the brainstem known as the ventromedial spinal trigeminal nucleus (SpV), which is known to be active during sneezing (2). These neurons send electrical signals (3) to neurons in another brainstem region called the caudal ventral respiratory group (cVRG), which controls exhalation, thus driving the initiation and propagation of sneezing (4). Ablating the nasal neurons or disrupting NMB signaling led to a significantly reduced sneezing reflex in the mice. WEB | PDF © 1986–2021 The Scientist.

Keyword: Brain imaging; Pain & Touch
Link ID: 28014 - Posted: 10.02.2021

Abby Olena Delivering anything therapeutic to the brain has long been a challenge, largely due to the blood-brain barrier, a layer of cells that separates the vessels that supply the brain with blood from the brain itself. Now, in a study published August 12 in Nature Biotechnology, researchers have found that double-stranded RNA-DNA duplexes with attached cholesterol can enter the brains of both mice and rats and change the levels of targeted proteins. The results suggest a possible route to developing drugs that could target the genes implicated in disorders such as muscular dystrophy and amyotrophic lateral sclerosis (ALS). “It’s really exciting to have a study that’s focused on delivery to the central nervous system” with antisense oligonucleotides given systemically, says Michelle Hastings, who investigates genetic disease at the Rosalind Franklin University of Medicine and Science in Chicago and was not involved in the study. The authors “showed that it works for multiple targets, some clinically relevant.” In 2015, Takanori Yokota of Tokyo Medical and Dental University and colleagues published a study showing that a so-called heteroduplex oligonucleotide (HDO)—consisting of a short chain of both DNA and an oligonucleotide with modified bases paired with complementary RNA bound to a lipid on one end—was successful at decreasing target mRNA expression in the liver. Yokota’s team later joined forces with researchers at Ionis Pharmaceuticals to determine whether HDOs could cross the blood-brain barrier and target mRNA in the central nervous system. © 1986–2021 The Scientist.

Keyword: Genes & Behavior; ALS-Lou Gehrig's Disease
Link ID: 27998 - Posted: 09.18.2021

by Niko McCarty Brain scans from 16 mouse models of autism reveal at least four distinct patterns of brain activity, a new study suggests. The findings lend fresh support to the popular idea that autism is associated with a range of brain ‘signatures.’ Telltale neural signatures of autism have long proved elusive, with functional magnetic resonance imaging (fMRI) and other brain scanning technologies shouldering the blame for scattered and inconsistent results. “One big question is whether there’s a single signature of dysfunction in the brain of people with autism. And many people consider that to be, like, something that there must be,” says study investigator Alessandro Gozzi, senior researcher at the Istituto Italiano di Tecnologia in Rovereto, Italy. “If we’ve not found it yet, the blame must be on the method: fMRI.” The method gauges small changes in blood flow and oxygenation as an indirect measure of brain activity. For the new study, published in Molecular Psychiatry in August, Gozzi and his colleagues used fMRI to study brain connectivity patterns — or which brain regions ‘talk’ to each other, and to what degree. Brain regions are considered to be in communication if they have synchronous oscillations in blood flow. To tackle the question of reproducibility in fMRI, the researchers conducted their analysis in mice, anesthetizing the animals and fixing their heads in place to prevent any motion that could perturb brain signals. “We moved to a model organism where we can control, in exquisite detail, many of the factors that are considered to be at the basis of this variability, this unreliability in imaging,” Gozzi says. © 2021 Simons Foundation

Keyword: Autism; Brain imaging
Link ID: 27982 - Posted: 09.11.2021

Jordana Cepelewicz Neuroscientists are the cartographers of the brain’s diverse domains and territories — the features and activities that define them, the roads and highways that connect them, and the boundaries that delineate them. Toward the front of the brain, just behind the forehead, is the prefrontal cortex, celebrated as the seat of judgment. Behind it lies the motor cortex, responsible for planning and coordinating movement. To the sides: the temporal lobes, crucial for memory and the processing of emotion. Above them, the somatosensory cortex; behind them, the visual cortex. Not only do researchers often depict the brain and its functions much as mapmakers might draw nations on continents, but they do so “the way old-fashioned mapmakers” did, according to Lisa Feldman Barrett, a psychologist at Northeastern University. “They parse the brain in terms of what they’re interested in psychologically or mentally or behaviorally,” and then they assign the functions to different networks of neurons “as if they’re Lego blocks, as if there are firm boundaries there.” But a brain map with neat borders is not just oversimplified — it’s misleading. “Scientists for over 100 years have searched fruitlessly for brain boundaries between thinking, feeling, deciding, remembering, moving and other everyday experiences,” Barrett said. A host of recent neurological studies further confirm that these mental categories “are poor guides for understanding how brains are structured or how they work.” Neuroscientists generally agree about how the physical tissue of the brain is organized: into particular regions, networks, cell types. But when it comes to relating those to the task the brain might be performing — perception, memory, attention, emotion or action — “things get a lot more dodgy,” said David Poeppel, a neuroscientist at New York University. All Rights Reserved © 2021

Keyword: Brain imaging; Attention
Link ID: 27963 - Posted: 08.25.2021

Amanda Heidt Scientists have discovered two types of glial cells in the brains of adult mice—an astrocyte and an oligodendrocyte progenitor cell—after nudging neural stem cells to rise from dormancy, according to a study published June 10 in Science. The results suggest new roles for glial cells, best known for providing support to neurons, and could prompt a better understanding of how brains remain plastic into adulthood, when the vast majority of neurons no longer undergo cell division. This study is “a very important addition to the whole story about these fascinating [stem] cells that exist in the adult brain of rodents that have the capacity to generate new cells,” says Arturo Alvarez-Buylla, a developmental neuroscientist at the University of California, San Francisco, who was not involved in the work. “Understanding adult stem cells is fundamental to really know the kinds of plasticity that exist after the developmental period is over.” Most mammalian brain cells, be they neurons or glia, are generated during embryonic development, and reservoirs of stem cells become largely, if not entirely, dormant in adulthood. The small trickle of activity that is left can help the brain respond to change, sometimes by generating new neurons to help with learning or by producing cells in response to injury or disease. One pool exists in the brains of adult humans and mice, in an area called the ventricular-subventricular zone (V-SVZ). The walls of the two lateral ventricles, cavities filled with cerebrospinal fluid, are lined with stem cells, and along these walls, the cells have a regional identity—where a stem cell lies on the wall dictates what it differentiates into. This feature has been well-characterized for neuronal subtypes, which are synthesized within discrete domains on the lateral wall. Glial cells are known to be generated at low levels along the septal wall, but the specific subtypes remain unknown because the cells along this wall generally remain inactive. © 1986–2021 The Scientist.

Keyword: Development of the Brain; Neurogenesis
Link ID: 27921 - Posted: 07.24.2021

Researchers at the University of Chicago and Argonne National Laboratory have imaged an entire mouse brain across five orders of magnitude of resolution, a step which researchers say will better connect existing imaging approaches and uncover new details about the structure of the brain. The advance, which was published on June 9 in NeuroImage, will allow scientists to connect biomarkers at the microscopic and macroscopic level. It leveraged existing advanced X-ray microscopy techniques to bridge the gap between MRI and electron microscopy imaging, providing a viable pipeline for multiscale whole brain imaging within the same brain. “Our lab is really interested in mapping brains at multiple scales to get an unbiased description of what brains look like,” said senior author Narayanan “Bobby” Kasthuri, assistant professor of neurobiology at UChicago and scientist at Argonne. “When I joined the faculty here, one of the first things I learned was that Argonne had this extremely powerful X-ray microscope, and it hadn’t been used for brain mapping yet, so we decided to try it out.” The microscope uses a type of imaging called synchrotron-based X-ray tomography, which can be likened to a “micro-CT”, or micro-computerized tomography scan. Thanks to the powerful X-rays produced by the synchrotron particle accelerator at Argonne, the researchers were able to image the entire mouse brain—roughly one cubic centimeter—at the resolution of a micron, 1/10,000 of a centimeter. It took roughly six hours to collect images of the entire brain, adding up to around 2 terabytes of data. This is one of the fastest approaches for whole brain imaging at this level of resolution.

Keyword: Brain imaging
Link ID: 27910 - Posted: 07.17.2021

By Lizzie Wade They were buried on a plantation just outside Havana. Likely few, if any, thought of the place as home. Most apparently grew up in West Africa, surrounded by family and friends. The exact paths that led to each of them being ripped from those communities and sold into bondage across the sea cannot be retraced. We don’t know their names and we don’t know their stories because in their new world of enslavement those truths didn’t matter to people with the power to write history. All we can tentatively say: They were 51 of nearly 5 million enslaved Africans brought to Caribbean ports and forced to labor in the islands’ sugar and coffee fields for the profit of Europeans. Nor do we know how or when the 51 died. Perhaps they succumbed to disease, or were killed through overwork or by a more explicit act of violence. What we do know about the 51 begins only with a gruesome postscript: In 1840, a Cuban doctor named José Rodriguez Cisneros dug up their bodies, removed their heads, and shipped their skulls to Philadelphia. He did so at the request of Samuel Morton, a doctor, anatomist, and the first physical anthropologist in the United States, who was building a collection of crania to study racial differences. And thus the skulls of the 51 were turned into objects to be measured and weighed, filled with lead shot, and measured again. Morton, who was white, used the skulls of the 51—as he did all of those in his collection—to define the racial categories and hierarchies still etched into our world today. After his death in 1851, his collection continued to be studied, added to, and displayed. In the 1980s, the skulls, now at the University of Pennsylvania Museum of Archaeology and Anthropology, began to be studied again, this time by anthropologists with ideas very different from Morton’s. They knew that society, not biology, defines race. © 2021 American Association for the Advancement of Science.

Keyword: Brain imaging; Evolution
Link ID: 27902 - Posted: 07.10.2021

Laura Sanders A new view of the human brain shows its cellular residents in all their wild and weird glory. The map, drawn from a tiny piece of a woman’s brain, charts the varied shapes of 50,000 cells and 130 million connections between them. This intricate map, named H01 for “human sample 1,” represents a milestone in scientists’ quest to provide ever more detailed descriptions of a brain (SN: 2/7/14). “It’s absolutely beautiful,” says neuroscientist Clay Reid at the Allen Institute for Brain Science in Seattle. “In the best possible way, it’s the beginning of something very exciting.” Scientists at Harvard University, Google and elsewhere prepared and analyzed the brain tissue sample. Smaller than a sesame seed, the bit of brain was about a millionth of an entire brain’s volume. It came from the cortex — the brain’s outer layer responsible for complex thought — of a 45-year-old woman undergoing surgery for epilepsy. After it was removed, the brain sample was quickly preserved and stained with heavy metals that revealed cellular structures. The sample was then sliced into more than 5,000 wafer-thin pieces and imaged with powerful electron microscopes. Computational programs stitched the resulting images back together and artificial intelligence programs helped scientists analyze them. A short description of the resulting view was published as a preprint May 30 to bioRxiv.org. The full dataset is freely available online. black background with green and purple nerve cells with lots of long tendrils These two neurons are mirror symmetrical. It’s unclear why these cells take these shapes. Lichtman Lab/Harvard University, Connectomics Team/Google For now, researchers are just beginning to see what’s there. “We have really just dipped our toe into this dataset,” says study coauthor Jeff Lichtman, a developmental neurobiologist at Harvard University. Lichtman compares the brain map to Google Earth: “There are gems in there to find, but no one can say they’ve looked at the whole thing.” © Society for Science & the Public 2000–2021.

Keyword: Brain imaging
Link ID: 27858 - Posted: 06.16.2021

By Thomas Ling Neuroscientists are poised to gain new insights into how our minds work, thanks to a breakthrough in non-invasive 3D brain scanning. Testing the new technique – which is called diffuse optical localisation imaging (DOLI) – researchers from the University of Zurich injected a live mouse with special fluorescent microdroplets that became distributed throughout the bloodstream. Highly efficient short-wave cameras (which take advantage of a near-infrared spectral window) tracked the fluorescent to draw a map of the deep cerebral network within the mouse’s brain. Previous microscopy techniques generated unclear images due to intense light scattering. However, the DOLI technique can create a clear picture of the brain at the capillary level by using a fluorescent filled with tiny lead-sulfide-based particles called quantum dots. Additionally, unlike past procedures, DOLI does not need to break the animal’s skull and scalp to work. It is hoped the new non-invasive technique will lead to a better understanding of how brains work, including how neurological diseases first form. “Enabling high-resolution optical observations in deep living tissues represents a long-standing goal in the biomedical imaging field,” said research team leader Prof Daniel Razansky, who published the group’s findings in Optica, The Optical Society’s journal. (C) BBC

Keyword: Brain imaging
Link ID: 27836 - Posted: 05.29.2021

Ian Sample Science editor A man who was paralysed from the neck down in an accident more than a decade ago has written sentences using a computer system that turns imagined handwriting into words. It is the first time scientists have created sentences from brain activity linked to handwriting and paves the way for more sophisticated devices to help paralysed people communicate faster and more clearly. The man, known as T5, who is in his 60s and lost practically all movement below his neck after a spinal cord injury in 2007, was able to write 18 words a minute when connected to the system. On individual letters, his “mindwriting” was more than 94% accurate. Frank Willett, a research scientist on the project at Stanford University in California, said the approach opened the door to decoding other imagined actions, such as 10-finger touch typing and attempted speech for patients who had permanently lost their voices. “Instead of detecting letters, the algorithm would be detecting syllables, or rather phonemes, the fundamental unit of speech,” he said. Amy Orsborn, an expert in neural engineering at the University of Washington in Seattle, who was not involved in the work, called it “a remarkable advance” in the field. Scientists have developed numerous software packages and devices to help paralysed people communicate, ranging from speech recognition programs to the muscle-driven cursor system created for the late Cambridge cosmologist Stephen Hawking, who used a screen on which a cursor automatically moved over the letters of the alphabet. To select one, and to build up words, he simply tensed his cheek. © 2021 Guardian News & Media Limited

Keyword: Brain imaging; Robotics
Link ID: 27822 - Posted: 05.15.2021

By Charles Q. Choi With the help of headsets and backpacks on mice, scientists are using light to switch nerve cells on and off in the rodents’ brains to probe the animals’ social behavior, a new study shows. These remote control experiments are revealing new insights on the neural circuitry underlying social interactions, supporting previous work suggesting minds in sync are more cooperative, researchers report online May 10 in Nature Neuroscience. The new devices rely on optogenetics, a technique in which researchers use bursts of light to activate or suppress the brain nerve cells, or neurons, often using tailored viruses to genetically modify cells so they respond to illumination (SN: 1/15/10). Scientists have used optogenetics to probe neural circuits in mice and other lab animals to yield insights on how they might work in humans (SN: 10/22/19). Optogenetic devices often feed light to neurons via fiber-optic cables, but such tethers can interfere with natural behaviors and social interactions. While scientists recently developed implantable wireless optogenetic devices, these depend on relatively simple remote controls or limited sets of preprogrammed instructions. These new fully implantable optogenetic arrays for mice and rats can enable more sophisticated research. Specifically, the researchers can adjust each device’s programming during the course of experiments, “so you can target what an animal does in a much more complex way,” says Genia Kozorovitskiy, a neurobiologist at Northwestern University in Evanston, Ill. © Society for Science & the Public 2000–2021.

Keyword: Brain imaging
Link ID: 27812 - Posted: 05.12.2021

Researchers are now able to wirelessly record the directly measured brain activity of patients living with Parkinson’s disease and to then use that information to adjust the stimulation delivered by an implanted device. Direct recording of deep and surface brain activity offers a unique look into the underlying causes of many brain disorders; however, technological challenges up to this point have limited direct human brain recordings to relatively short periods of time in controlled clinical settings. This project, published in the journal Nature Biotechnology, was funded by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative. “This is really the first example of wirelessly recording deep and surface human brain activity for an extended period of time in the participants’ home environment,” said Kari Ashmont, Ph.D., project manager for the NIH BRAIN Initiative. “It is also the first demonstration of adaptive deep brain stimulation at home.” Deep brain stimulation (DBS) devices are approved by the U. S. Food and Drug Administration for the management of Parkinson’s disease symptoms by implanting a thin wire, or electrode, that sends electrical signals into the brain. In 2018, the laboratory of Philip Starr, M.D., Ph.D. at the University of California, San Francisco, developed an adaptive version of DBS that adapts its stimulation only when needed based on recorded brain activity. In this study, Dr. Starr and his colleagues made several additional improvements to the implanted technology.

Keyword: Brain imaging
Link ID: 27800 - Posted: 05.05.2021

Enhancing the brain’s lymphatic system when administering immunotherapies may lead to better clinical outcomes for Alzheimer’s disease patients, according to a new study in mice. Results published April 28 in Nature suggest that treatments such as the immunotherapies BAN2401 or aducanumab might be more effective when the brain’s lymphatic system can better drain the amyloid-beta protein that accumulates in the brains of those living with Alzheimer’s. Major funding for the research was provided by the National Institute on Aging (NIA), part of the National Institutes of Health, and all study data is now freely available to the broader scientific community. “A broad range of research on immunotherapies in development to treat Alzheimer’s by targeting amyloid-beta has not to date demonstrated consistent results,” said NIA Director Richard J. Hodes, M.D. “While this study’s findings require further confirmation, the link it has identified between a well-functioning lymphatic system in the brain and the ability to reduce amyloid-beta accumulation may be a significant step forward in pursuing this class of therapeutics.” Abnormal buildup of amyloid-beta is one hallmark of Alzheimer’s disease. The brain’s lymphatic drainage system, which removes cellular debris and other waste, plays an important part in that accumulation. A 2018 NIA-supported study showed a link between impaired lymphatic vessels and increased amyloid-beta deposits in the brains of aging mice, suggesting these vessels could play a role in age-related cognitive decline and Alzheimer’s. The lymphatic system is made up of vessels which run alongside blood vessels and which carry immune cells and waste to lymph nodes. Lymphatic vessels extend into the brain’s meninges, which are membranes that surround the brain and spinal cord.

Keyword: Alzheimers; Sleep
Link ID: 27795 - Posted: 05.01.2021