By Yasemin Saplakoglu Bacteria are in, around and all over us. They thrive in almost every corner of the planet, from deep-sea hydrothermal vents to high up in the clouds, to the crevices of your ears, mouth, nose and gut. But scientists have long assumed that bacteria can’t survive in the human brain. The powerful blood-brain barrier, the thinking goes, keeps the organ mostly free from outside invaders. But are we sure that a healthy human brain doesn’t have a microbiome of its own? Over the last decade, initial studies have presented conflicting evidence. The idea has remained controversial, given the difficulty of obtaining healthy, uncontaminated human brain tissue that could be used to study possible microbial inhabitants. Recently, a study published in Science Advances provided the strongest evidence yet (opens a new tab) that a brain microbiome can and does exist in healthy vertebrates — fish, specifically. Researchers at the University of New Mexico discovered communities of bacteria thriving in salmon and trout brains. Many of the microbial species have special adaptations that allow them to survive in brain tissue, as well as techniques to cross the protective blood-brain barrier. Matthew Olm (opens a new tab), a physiologist who studies the human microbiome at the University of Colorado, Boulder and was not involved with the study, is “inherently skeptical” of the idea that populations of microbes could live in the brain, he said. But he found the new research convincing. “This is concrete evidence that brain microbiomes do exist in vertebrates,” he said. “And so the idea that humans have a brain microbiome is not outlandish.” While fish physiology is, in many ways, similar to humans’, there are some key differences. Still, “it certainly puts another weight on the scale to think about whether this is relevant to mammals and us,” said Christopher Link (opens a new tab), who studies the molecular basis of neurodegenerative disease at the University of Colorado, Boulder and was also not involved in the work. © 2024 Simons Foundation

Keyword: Obesity; Brain imaging
Link ID: 29588 - Posted: 12.04.2024

' By Sofia Quaglia Flip open any neuroscience textbook and the depiction of a neuron will be roughly the same: a blobby, amoebalike cell body shooting out a long, thick strand. That strand is the axon, which conducts electrical signals to terminals where the cell communicates with other neurons. Axons have long been depicted as smooth and cylindrical, but a new study of mouse neurons challenges that view. Instead, it suggests their natural shape is more like a string of pearls. Even more provocatively, the authors propose those pearly bumps serve as control knobs, influencing how quickly and precisely the cell fires its signals. The study, published today in Nature Neuroscience, should “100%” change how we’ve been thinking about neurons and their signals, says senior author Shigeki Watanabe, a molecular neuroscientist at John Hopkins University. Some outsiders agree. The findings are “highly significant and I think have been overlooked for quite some time,” says evolutionary biologist Pawel Burkhardt of the University of Bergen, who recently spotted similar pearl structures in neurons from tiny marine invertebrates known as comb jellies. Yet several experts in the field contest the findings. Some cite potential confounding effects of the preparation and freezing method used to preserve cells before imaging. And some doubt the work totally upends what’s known about the true shape of the axon. “I think it’s true that [the axon is] not a perfect tube, but it’s not also just this kind of accordion that they show,” says neuroscientist Christophe Leterrier from Aix-Marseille University, who calls the study “a controversial addition to the literature.” Since the mid-1960s, microscopists have seen that axons can scrunch up to form beads when they are diseased or under other stress. Leterrier has called these temporary beads “stress balls for the brain” and found evidence that they prevent cellular damage from spreading. Other studies suggest even normal axons bulge temporarily when cargo traveling to and from the cell nucleus forms a traffic jam, like the elephant bulging inside the body of a boa in the children’s book The Little Prince.

Keyword: Brain imaging
Link ID: 29586 - Posted: 12.04.2024

By Claudia López Lloreda For decades, researchers have considered the brain “immune privileged”—protected from the vagaries of the body’s immune system. But building evidence suggests that the brain may be more immunologically active than previously thought, well beyond its own limited immune response. The choroid plexus in particular—the network of blood vessels and cerebrospinal-fluid (CSF)-producing epithelial cells that line the organ’s ventricles—actively recruits immune cells from both the periphery and the CSF, according to a new study in mice. The epithelial layer of the choroid plexus shields the rest of the brain from toxic substances, pathogens and other molecules that circulate in the blood. Dysfunction and neuroinflammation in the choroid plexus is associated with aging and many neurological conditions, such as amyotrophic lateral sclerosis and Alzheimer’s disease. Even in the absence of inflammation, the choroid plexus harbors immune cells, some of which reside in the space between the vessels and the epithelial layer, and some on the epithelial surface. During an immune response, it also contains recruited cells, such as macrophages and other leukocytes, and pro-inflammatory signals, previous research has shown. But those findings offered only a snapshot of the cells’ locations, says Maria Lehtinen, professor of pathology at Harvard Medical School, who led the new work. “Just because [the cell] is in the tissue doesn’t mean it’s necessarily crossing or has gone in the direction that you anticipate that it would be going in.” How the choroid plexus gatekeeps immune cells remains a big question in the field, says Michal Schwartz, a neuroimmunologist at the Weizmann Institute of Science, who was not involved with the new work. © 2024 Simons Foundation

Keyword: Neuroimmunology
Link ID: 29571 - Posted: 11.23.2024

By Sara Reardon Researchers have mapped nearly 140,000 neurons in the fruit-fly brain. This version shows the 50 largest. Credit: Tyler Sloan and Amy Sterling for FlyWire, Princeton University (ref. 1) A fruit fly might not be the smartest organism, but scientists can still learn a lot from its brain. Researchers are hoping to do that now that they have a new map — the most complete for any organism so far — of the brain of a single fruit fly (Drosophila melanogaster). The wiring diagram, or ‘connectome’, includes nearly 140,000 neurons and captures more than 54.5 million synapses, which are the connections between nerve cells. “This is a huge deal,” says Clay Reid, a neurobiologist at the Allen Institute for Brain Science in Seattle, Washington, who was not involved in the project but has worked with one of the team members who was. “It’s something that the world has been anxiously waiting for, for a long time.” The map1 is described in a package of nine papers about the data published in Nature today. Its creators are part of a consortium known as FlyWire, co-led by neuroscientists Mala Murthy and Sebastian Seung at Princeton University in New Jersey. Seung and Murthy say that they’ve been developing the FlyWire map for more than four years, using electron microscopy images of slices of the fly’s brain. The researchers and their colleagues stitched the data together to form a full map of the brain with the help of artificial-intelligence (AI) tools. But these tools aren’t perfect, and the wiring diagram needed to be checked for errors. The scientists spent a great deal of time manually proofreading the data — so much time that they invited volunteers to help. In all, the consortium members and the volunteers made more than three million manual edits, according to co-author Gregory Jefferis, a neuroscientist at the University of Cambridge, UK. (He notes that much of this work took place in 2020, when fly researchers were at loose ends and working from home during the COVID-19 pandemic.) © 2024 Springer Nature Limited

Keyword: Brain imaging; Development of the Brain
Link ID: 29508 - Posted: 10.05.2024

By Angie Voyles Askham Most people visit the Minnesota State Fair for a fun-filled day of fried food, farm animals and carnival rides. Not Ka Ip. He saw the annual event as the perfect setting for a new experiment. Ip, assistant professor of child development at the University of Minnesota, is particularly interested in executive function: the set of skills, such as organization and impulse control, people need to plan and achieve goals. Children from lower socioeconomic backgrounds tend to perform worse on tests of these skills than do their more privileged peers, past research shows. But that gap may reflect where those skills are typically tested: a quiet lab, in which some children may feel out of their element, Ip says. “That may not actually mimic their actual day-to-day environment.” Which is why Ip started to devise a series of experiments to conduct at the less-than-serene state fair. “We really want to understand how, for example, unpredictability in the home environment is related to executive function development,” he says. The fair also offered a way to recruit children from a wider swath of society than researchers can often find at a university, he adds. Last month, after a year of planning, Ip and his team lugged a trolley full of equipment to the fairgrounds outside Minneapolis. There, they collected functional near-infrared spectroscopy (fNIRS) data on 75 children aged 3 to 7 as they played a computer game that tests impulse control. The team aims to evaluate whether the bustling surroundings affect participants’ performances and neural activity differently based on their background. © 2024 Simons Foundation

Keyword: Brain imaging; Attention
Link ID: 29490 - Posted: 09.25.2024

Jon Hamilton Scientists have created a virtual brain network that can predict the behavior of individual neurons in a living brain. The model is based on a fruit fly’s visual system, and it offers scientists a way to quickly test ideas on a computer before investing weeks or months in experiments involving actual flies or other lab animals. “Now we can start with a guess for how the fly brain might work before anyone has to make an experimental measurement,” says Srini Turaga, a group leader at the Janelia Research Campus, a part of the Howard Hughes Medical Institute (HHMI). The approach, described in the journal Nature, also suggests that power-hungry artificial intelligence systems like ChatGPT might consume much less energy if they used some of the computational strategies found in a living brain. A fruit fly brain is “small and energy efficient,” says Jakob Macke, a professor at the University of Tübingen and an author of the study. “It’s able to do so many computations. It’s able to fly, it’s able to walk, it’s able to detect predators, it’s able to mate, it’s able to survive—using just 100,000 neurons.” In contrast, AI systems typically require computers with tens of billions of transistors. Worldwide, these systems consume as much power as a small country. “When we think about AI right now, the leading charge is to make these systems more power efficient,” says Ben Crowley, a computational neuroscientist at Cold Spring Harbor Laboratory who was not involved in the study. Borrowing strategies from the fruit fly brain might be one way to make that happen, he says. © 2024 npr

Keyword: Brain imaging; Evolution
Link ID: 29484 - Posted: 09.18.2024

Nicola Davis Science correspondent Researchers have gained new insight into how and why some people experience depression after finding a particular brain network is far bigger in people living with the condition. The surface of the brain is a communication junction box at which different areas talk to each other to carry out particular processes. But there is a finite amount of space for these networks to share. Now researchers say that in people with depression, a larger part of the brain is involved in the network that controls attention to rewards and threats than in those without depression. “It’s taking up more real estate on the brain surface than we see is typical in healthy controls,” said Dr Charles Lynch, a co-author of the research, from Weill Cornell Medicine in New York. He added that expansion meant the size of other – often neighbouring – brain networks were smaller. Writing in the journal Nature, Lynch and colleagues report how they used precision functional mapping, a new approach to brain imaging that analyses a host of fMRI (functional MRI) scans from each individual. The team applied this method to 141 people with depression and 37 people without it, enabling them to measure accurately the size of each participant’s brain networks. They then took the average size for each group. They found that a part of the brain called the frontostriatal salience network was expanded by 73% on average in participants with depression compared with healthy controls. © 2024 Guardian News & Media Limited

Keyword: Depression; Brain imaging
Link ID: 29468 - Posted: 09.07.2024

By Rodrigo Pérez Ortega Names can be deceiving. One might think “cerebrospinal fluid” only lives in the brain and spinal cord. Indeed, that’s what scientists and doctors have largely believed for centuries. But the clear liquid—which cleans, feeds, and protects the organs it surrounds—also bathes the body’s nerves, researchers report today in Science Advances. “This is one of the [most] important papers in this area,” says Karl Bechter, a clinical neurologist at Ulm University who was not involved in the study. In the past, he and others have suggested instances in which cerebrospinal fluid (CSF) permeates nerves, but he says this is the first study that shows it can travel far throughout the body. The finding could open new ways to deliver drugs to some of the most inaccessible parts of the body. The human body is a bundle of nerves. Besides the head honchos that make up the central nervous system—the brain and spinal cord—kilometers of spindly fibers snake their way throughout our anatomy. Here, they form a peripheral nervous system that fires the signals that allow us to do everything from walking to feeling pain. Yet even though the two systems interface, previous anatomy studies indicated CSF was restricted to the central nervous system. Things changed 2.5 years ago when Edward Scott, a stem cell biologist at the University of Florida, and his surgeon colleague Joe Pessa noticed something strange during a plastic surgery study. Pessa was researching ways to avoid damaging CSF-containing structures and nerves during surgical procedures. When the scientists injected saline into the brain chambers of human cadavers that contained CSF, a peripheral nerve in the wrist swelled up. They then decided to explore further, injecting a fluorescent liquid in live mice’s brain chambers to track where the liquid went. The dye somehow made its way to the sciatic nerve, which runs throughout the back of the leg. Intrigued, the team decided to repeat the experiment in mice using a much finer tracer: nanoparticles of gold. These tiny particles can be detected through both light and electron microscopy and can be tailored to specific sizes.

Keyword: Brain imaging; Biomechanics
Link ID: 29465 - Posted: 09.07.2024

By R. Douglas Fields It is late at night. You are alone and wandering empty streets in search of your parked car when you hear footsteps creeping up from behind. Your heart pounds, your blood pressure skyrockets. Goose bumps appear on your arms, sweat on your palms. Your stomach knots and your muscles coil, ready to sprint or fight. Now imagine the same scene, but without any of the body’s innate responses to an external threat. Would you still feel afraid? Experiences like this reveal the tight integration between brain and body in the creation of mind — the collage of thoughts, perceptions, feelings and personality unique to each of us. The capabilities of the brain alone are astonishing. The supreme organ gives most people a vivid sensory perception of the world. It can preserve memories, enable us to learn and speak, generate emotions and consciousness. But those who might attempt to preserve their mind by uploading its data into a computer miss a critical point: The body is essential to the mind. How is this crucial brain-body connection orchestrated? The answer involves the very unusual vagus nerve. The longest nerve in the body, it wends its way from the brain throughout the head and trunk, issuing commands to our organs and receiving sensations from them. Much of the bewildering range of functions it regulates, such as mood, learning, sexual arousal and fear, are automatic and operate without conscious control. These complex responses engage a constellation of cerebral circuits that link brain and body. The vagus nerve is, in one way of thinking, the conduit of the mind. Nerves are typically named for the specific functions they perform. Optic nerves carry signals from the eyes to the brain for vision. Auditory nerves conduct acoustic information for hearing. The best that early anatomists could do with this nerve, however, was to call it the “vagus,” from the Latin for “wandering.” The wandering nerve was apparent to the first anatomists, notably Galen, the Greek polymath who lived until around the year 216. But centuries of study were required to grasp its complex anatomy and function. This effort is ongoing: Research on the vagus nerve is at the forefront of neuroscience today. © 2024.Simons Foundation

Keyword: Emotions; Obesity
Link ID: 29454 - Posted: 08.28.2024

By Holly Barker Machine-learning models can predict a neuron’s location based on recorded bursts of activity, a new preprint suggests. The findings may provide novel insights into how the brain integrates signals from different regions, the researchers say. The algorithm—trained on electrode recordings of neurons in mice—appeared to learn a cell’s whereabouts from its interspike interval, the sequence of delays between blips of activity. And after deciphering the spike pattern from one mouse, the tool predicted neuronal locations based on recordings from another rodent. That conservation between animals suggests the information serves some useful brain function, or at least doesn’t get in the way, says lead investigator Keith Hengen, assistant professor of biology at Washington University in St. Louis. Although more research is needed, the anatomical information embedded in interspike intervals could—in theory—provide contextual information for neuronal computations. For example, the brain might process signals from thalamic neurons differently from those in the hippocampus, says study investigator Aidan Schneider, a graduate student in Hengen’s lab. Schneider and his colleagues trained the model using tens of thousands of Neuropixels probe recordings from 58 awake mice, published by the Allen Institute. When Schneider’s team presented the algorithm with fresh data, it could decipher whether a given neuron resided in the hippocampus, midbrain, thalamus or visual cortex 89 percent of the time, once the team removed noise from the data. (Random guesses would be correct 25 percent of the time.) But the tool was less able to pinpoint specific substructures within those regions. It’s a great example of the kinds of insights that labs poring over huge datasets can produce, says Drew Headley, assistant professor of molecular and behavioral neuroscience at Rutgers University, who was not involved in the study. But the findings may simply echo published reports of variations in spiking activity across different brain regions, he says. © 2024 Simons Foundation

Keyword: Brain imaging
Link ID: 29452 - Posted: 08.28.2024

By Michael Eisenstein An analysis of almost 50,000 brain scans1 has revealed five distinct patterns of brain atrophy associated with ageing and neurodegenerative disease. The analysis has also linked the patterns to lifestyle factors such as smoking and alcohol consumption, as well as to genetic and blood-based markers associated with health status and disease risk. The work is a “methodological tour de force” that could greatly advance researchers’ understanding of ageing, says Andrei Irimia, a gerontologist at the University of Southern California in Los Angeles, who was not involved in the work. “Prior to this study, we knew that brain anatomy changes with ageing and disease. But our ability to grasp this complex interaction was far more modest.” The study was published on 15 August in Nature Medicine. Ageing can induce not only grey hair, but also changes in brain anatomy that are visible on magnetic resonance imaging (MRI) scans, with some areas shrivelling or undergoing structural alterations over time. But these transformations are subtle. “The human eye is not able to perceive patterns of systematic brain changes” associated with this decline, says Christos Davatzikos, a biomedical-imaging specialist at the University of Pennsylvania in Philadelphia and an author of the paper. Previous studies have shown that machine-learning methods can extract the subtle fingerprints of ageing from MRI data. But these studies were often limited in scope and most included data from a relatively small number of people. © 2024 Springer Nature Limited

Keyword: Development of the Brain; Brain imaging
Link ID: 29446 - Posted: 08.21.2024

By Tina Hesman Saey A mind-bending parasite may one day deliver drugs to the brain. Toxoplasma gondii is a single-celled parasite that famously makes mice lose their fear of cats, but also can cause deadly foodborne illnesses (SN: 1/14/20). Now, researchers have engineered the parasite to deliver large therapeutic proteins to the brains of mice and into human brain cells grown in lab dishes, an international team of scientists reports July 29 in Nature Microbiology. Such proteins and the genes that produce them are often too big for viruses — the most common courier for gene therapy — to carry (SN: 10/20/23). If the parasite can be made safe for human use, the technique may eventually help treat a variety of neurological conditions. While critics doubt that the parasitic villain can ever be turned into a helpful hero, some researchers are intrigued by the idea. Microbes such as bacteria and parasites are usually viewed as bad guys, says Sara Molinari, a bacterial synthetic biologist at the University of Maryland in College Park who was not involved with the work. But microbes have evolved “pretty sophisticated relationships with our bodies,” she says. “The idea that we can leverage this relationship to instruct them to do good things for us is actually groundbreaking.” Current methods of delivering therapies to the brain often produce unpredictable results or have a hard time penetrating the protective shield known as the blood-brain barrier, says Shahar Bracha, a bioengineer and neuroscientist at MIT (SN: 5/2/23). © Society for Science & the Public 2000–2024.

Keyword: Brain imaging; Drug Abuse
Link ID: 29414 - Posted: 07.31.2024

By Laura Dattaro When John Tuthill was a postdoctoral researcher at Harvard Medical School, he worked just down the hall from Wei-Chung Allen Lee, who was developing new technology to image and map cell connections in the central nervous system. Lee wanted to use his technique in the fruit fly Drosophila, but he knew that other groups were already making such images of the fly brain. So Tuthill, who was studying touch stimuli in Drosophila, suggested Lee pivot to map the fly’s ventral nerve cord (VNC) instead. A decade later, Tuthill, Lee and colleagues have published a map of the connections among motor neurons in a female fly’s VNC, which is analogous to the spinal cord in mammals. The diagram, published on 26 June in Nature, details roughly 45 million synapses that connect nearly 15,000 neurons, and is the second such connectome to be released. A different team, at Howard Hughes Medical Institute’s Janelia Research Campus, published a male fly’s VNC connectome to eLife’s preprint server in June 2023. (The team posted an updated, reviewed preprint on 23 May 2024.) “The connectome is only useful if you can connect it to the muscles,” says Tuthill, associate professor of neuroscience at the University of Washington. “The output of the connectome is the activity of motor neurons.” With connectomes from both a male and a female fly, researchers are starting to look for differences not only between individuals, but between the sexes. An initial comparison of the two connectomes, posted to bioRxiv on 28 June by members of both teams, including Tuthill and Lee, identified circuits that appear to control sex-specific behaviors, including male courtship songs and the female extension of an organ used to deposit eggs. © 2024 Simons Foundation

Keyword: Brain imaging
Link ID: 29407 - Posted: 07.27.2024

By Phie Jacobs Is there really such a thing as a “male” or “female” brain? Sex certainly seems to affect a person’s risk of developing various psychiatric and other brain-related conditions—but scientists aren’t entirely sure why. Attention-deficit/hyperactivity disorder for example, is more commonly diagnosed in individuals who were assigned male at birth (AMAB), whereas those assigned female at birth (AFAB) are more likely to exhibit symptoms of anxiety. It’s unclear, however, whether these differences are actually driven by sex, or have more to do with how people are perceived and treated based on their sex or gender. Now, new research suggests sex and gender are associated with distinct brain networks. Published today in Science Advances, the findings draw on brain imaging data from nearly 5000 children to reveal that gender and sex aren’t just distinct from one another in society—they also play unique roles in biology. In science, the term “biological sex” encompasses a variety of genetic, hormonal, and anatomical characteristics. People are typically assigned “male” or “female” as their sex at birth, although the medical establishment in recent years has begun to acknowledge that sex doesn’t always fall neatly into binary categories. Indeed, about 0.05% of children born in the United States are assigned intersex at birth. Gender, by contrast, has more to do with a person’s attitudes, feelings, and behavior—and may not always align with the sex they were assigned at birth. These nuances often go unrecognized in neuroscience, says Sheila Shanmugan, a reproductive psychiatrist at the University of Pennsylvania who wasn’t involved in the new study. Sex and gender-based differences in the brain “have historically been understudied,” she explains, “and terms describing each are often conflated.” © 2024 American Association for the Advancement of Science.

Keyword: Sexual Behavior; Brain imaging
Link ID: 29393 - Posted: 07.13.2024

By Erin Garcia de Jesús In spring 2022, a handful of red foxes in Wisconsin were behaving oddly. Veterinary pathologist Betsy Elsmo learned that a local wildlife rehabilitation center was caring for foxes with neurological symptoms like seizures, tremors, uncoordinated movements and lethargy. But tests for common pathogens like canine distemper virus and rabies that typically cause the symptoms came back negative. Then a red fox kit tested positive for influenza A. This group of viruses includes seasonal flus that cause respiratory disease in people and many other strains that commonly circulate among animals such as waterfowl and other birds. “I was surprised,” says Elsmo, of the University of Wisconsin–Madison. “And to be honest, at first I kind of wrote it off.” That is, until a veterinary technician at the rehab center sent Elsmo a study describing cases of avian influenza in red foxes in the Netherlands. Examinations of the Wisconsin kit’s tissues under the microscope revealed lesions in the brain, lung and heart that matched what had been seen in the Netherlands animals. “And I thought, I think it is [bird flu],” she recalls. Additional testing confirmed the diagnosis in the kit and the other foxes, Elsmo and colleagues reported in the December 2023 Emerging Infectious Diseases. The animals had contracted a lethal strain of H5N1 avian influenza that emerged in late 2020 in Europe and has since spread around the world. At the time infections were discovered in the Wisconsin red foxes, bird flu was expanding its incursion into North America. Since H5N1 arrived on North American shores in December 2021, it has infected animals as wide-ranging as polar bears, skunks, sea lions, bottlenosed dolphins and cows (SN: 7/8/24). And one unwelcome revelation of the ongoing outbreak is the virus’s propensity to invade the brains of myriad mammals. © Society for Science & the Public 2000–2024.

Keyword: Stress
Link ID: 29392 - Posted: 07.13.2024

By Tyler Sloan If I ask you to picture a group of “neurons firing,” what comes to mind? For most people, it’s a few isolated neurons flashing in synchrony. This type of minimalist representation of neurons is common within neuroscience, inspired in part by Santiago Ramón y Cajal’s elegant depictions of the nervous system. His work left a deep mark on our intuitions, but the method he used—Golgi staining—highlights just 1 to 5 percent of neurons. More than a century later, researchers have mapped out brain connectivity in such detail that it easily becomes overwhelming; I vividly recall an undergraduate neurophysiology lecture in which the professor showed a wiring diagram of the primary visual cortex to make the point that it was too complex to understand. We’ve reached a point where simple wiring diagrams no longer suffice to represent what we’re learning about the brain. Advances in experimental and computational neuroscience techniques have made it possible to map brains in more detail than ever before. The wiring diagram for the whole fly brain, for example, mapped at single-synapse resolution, comprises 2.7 million cell-to-cell connections and roughly 150 million synapses. Building an intuitive understanding of this type of complexity will require new tools for representing neural connectivity in a way that is both meaningful and compact. To do this, we will have to embrace the elaborate and move beyond the single neuron to a more “maximalist” approach to visualizing the nervous system. I spent my Ph.D. studying the spinal cord, where commissural growth cones are depicted as pioneers on a railhead extending through uncharted territory. The watershed moment for me was seeing a scanning electron micrograph of the developing spinal cord for the first time and suddenly understanding the growth cone’s dense environment—its path was more like squeezing through a crowded concert than wandering across an empty field. I realized how poor my own intuitions were, which nudged me toward learning the art of 3D visualization. © 2024 Simons Foundation

Keyword: Brain imaging; Development of the Brain
Link ID: 29385 - Posted: 07.09.2024

By Sara Reardon By eavesdropping on the brains of living people, scientists have created the highest-resolution map yet of the neurons that encode the meanings of various words1. The results hint that, across individuals, the brain uses the same standard categories to classify words — helping us to turn sound into sense. The study is based on words only in English. But it’s a step along the way to working out how the brain stores words in its language library, says neurosurgeon Ziv Williams at the Massachusetts Institute of Technology in Cambridge. By mapping the overlapping sets of brain cells that respond to various words, he says, “we can try to start building a thesaurus of meaning”. The brain area called the auditory cortex processes the sound of a word as it enters the ear. But it is the brain’s prefrontal cortex, a region where higher-order brain activity takes place, that works out a word’s ‘semantic meaning’ — its essence or gist. Previous research2 has studied this process by analysing images of blood flow in the brain, which is a proxy for brain activity. This method allowed researchers to map word meaning to small regions of the brain. But Williams and his colleagues found a unique opportunity to look at how individual neurons encode language in real time. His group recruited ten people about to undergo surgery for epilepsy, each of whom had had electrodes implanted in their brains to determine the source of their seizures. The electrodes allowed the researchers to record activity from around 300 neurons in each person’s prefrontal cortex. © 2024 Springer Nature Limited

Keyword: Language; Brain imaging
Link ID: 29383 - Posted: 07.06.2024

By Paula Span About a month ago, Judith Hansen popped awake in the predawn hours, thinking about her father’s brain. Her father, Morrie Markoff, was an unusual man. At 110, he was thought to be the oldest in the United States. His brain was unusual, too, even after he recovered from a stroke at 99. Although he left school after the eighth grade to work, Mr. Markoff became a successful businessman. Later in life, his curiosity and creativity led him to the arts, including photography and sculpture fashioned from scrap metal. He was a healthy centenarian when he exhibited his work at a gallery in Los Angeles, where he lived. At 103, he published a memoir called “Keep Breathing.” He blogged regularly, pored over The Los Angeles Times daily, discussed articles in Scientific American and followed the national news on CNN and “60 Minutes.” Now he was nearing death, enrolled in home hospice care. “In the middle of the night, I thought, ‘Dad’s brain is so great,’” said Ms. Hansen, 82, a retired librarian in Seattle. “I went online and looked up ‘brain donation.’” Her search led to a National Institutes of Health web page explaining that its NeuroBioBank, established in 2013, collected post-mortem human brain tissue to advance neurological research. Through the site, Ms. Hansen contacted the nonprofit Brain Donor Project. It promotes and simplifies donations through a network of university brain banks, which distribute preserved tissue to research teams. Tish Hevel, the founder of the project, responded quickly, putting Ms. Hansen and her brother in touch with the brain bank at the University of California, Los Angeles. Brain donors may have neurological and other diseases, or they may possess healthy brains, like Mr. Markoff’s. “We’re going to learn so much from him,” Ms. Hevel said. “What is it about these superagers that allows them to function at such a high level for so long?” © 2024 The New York Times Company

Keyword: Development of the Brain; Brain imaging
Link ID: 29379 - Posted: 07.06.2024

By Adolfo Plasencia Recently, a group of Australian researchers demonstrated a “mind-reading” system called BrainGPT. The system can, according to its creators, convert thoughts (recorded with a non-invasive electrode helmet) into words that are displayed on a screen. Essentially, BrainGPT connects a multitasking EEG encoder to a large language model capable of decoding coherent and readable sentences from EEG signals. Is the mind, the last frontier of privacy, still a safe place to think one’s thoughts? I spoke with Harvard-based behavioral neurologist Alvaro Pascual-Leone, a leader in the study of neuroplasticity and noninvasive brain stimulation, about what it means and how we can protect ourselves. The reality is that the ability to read the brain and influence activity is already here. It’s no longer only in the realm of science fiction. Now, the question is, what exactly can we access and manipulate in the brain? Consider this example: If I instruct you to move a hand, I can tell if you are preparing to move, say, your right hand. I can even administer a precise “nudge” to your brain and make you move your right hand faster. And you would then claim, and fully believe, that you moved it yourself. However, I know that, in fact, it was me who moved it for you. I can even force you to move your left hand—which you were not going to move—and lead you to rationalize why you changed your mind when in fact, our intervention led to that action you perceive as your choice. We have done this experiment in our laboratory. In humans, we can modify brain activity by reading and writing in the brain, so to speak, though we can affect only very simple things right now. In animals, we can do much more complex things because we have much more precise control of the neurons and their timing. But the capacity for that modulation of smaller circuits progressively down to individual neurons in humans is going to come, including much more selective modification with optogenetic alternatives—that is, using light to control the activity of neurons. © 2024 NautilusNext Inc.,

Keyword: Brain imaging
Link ID: 29377 - Posted: 07.03.2024

Jon Hamilton About 170 billion cells are in the brain, and as they go about their regular tasks, they produce waste — a lot of it. To stay healthy, the brain needs to wash away all that debris. But how exactly it does this has remained a mystery. Now, two teams of scientists have published three papers that offer a detailed description of the brain's waste-removal system. Their insights could help researchers better understand, treat and perhaps prevent a broad range of brain disorders. The papers, all published in the journal Nature, suggest that during sleep, slow electrical waves push the fluid around cells from deep in the brain to its surface. There, a sophisticated interface allows the waste products in that fluid to be absorbed into the bloodstream, which takes them to the liver and kidneys to be removed from the body. One of the waste products carried away is amyloid, the substance that forms sticky plaques in the brains of patients with Alzheimer's disease. This illustration demonstrates how the thin film of sensors could be applied to the brain during surgery. There's growing evidence that in Alzheimer's disease, the brain's waste-removal system is impaired, says Jeffrey Iliff, who studies neurodegenerative diseases at the University of Washington but was not a part of the new studies. The new findings should help researchers understand precisely where the problem is and perhaps fix it, Iliff says. "If we restore drainage, can we prevent the development of Alzheimer's disease?" he asks. The new studies come more than a decade after Iliff and Dr. Maiken Nedergaard, a Danish scientist, first proposed that the clear fluids in and around the brain are part of a system to wash away waste products. The scientists named it the glymphatic system, a nod to the body's lymphatic system, which helps fight infection, maintain fluid levels and filter out waste products and abnormal cells. © 2024 npr

Keyword: Sleep
Link ID: 29369 - Posted: 06.26.2024