By Marla Broadfoot In Alexandre Dumas’s classic novel The Count of Monte-Cristo, a character named Monsieur Noirtier de Villefort suffers a terrible stroke that leaves him paralyzed. Though he remains awake and aware, he is no longer able to move or speak, relying on his granddaughter Valentine to recite the alphabet and flip through a dictionary to find the letters and words he requires. With this rudimentary form of communication, the determined old man manages to save Valentine from being poisoned by her stepmother and thwart his son’s attempts to marry her off against her will. Dumas’s portrayal of this catastrophic condition — where, as he puts it, “the soul is trapped in a body that no longer obeys its commands” — is one of the earliest descriptions of locked-in syndrome. This form of profound paralysis occurs when the brain stem is damaged, usually because of a stroke but also as the result of tumors, traumatic brain injury, snakebite, substance abuse, infection or neurodegenerative diseases like amyotrophic lateral sclerosis (ALS). The condition is thought to be rare, though just how rare is hard to say. Many locked-in patients can communicate through purposeful eye movements and blinking, but others can become completely immobile, losing their ability even to move their eyeballs or eyelids, rendering the command “blink twice if you understand me” moot. As a result, patients can spend an average of 79 days imprisoned in a motionless body, conscious but unable to communicate, before they are properly diagnosed. The advent of brain-machine interfaces has fostered hopes of restoring communication to people in this locked-in state, enabling them to reconnect with the outside world. These technologies typically use an implanted device to record the brain waves associated with speech and then use computer algorithms to translate the intended messages. The most exciting advances require no blinking, eye tracking or attempted vocalizations, but instead capture and convey the letters or words a person says silently in their head. © 2023 Annual Reviews

Keyword: Brain imaging; Language
Link ID: 28791 - Posted: 05.21.2023

Tess McClure Every few months, Cohen “Coey” Irwin lies on his back and lets the walls close in. Lights move overhead, scanning over the tattoos covering his cheeks. He lies suspended, his head encased by a padded helmet, ears blocked, as his body is shunted into a tunnel. The noise begins: a rhythmic crashing, loud as a jackhammer. For the next hour, an enormous magnet will produce finely detailed images of Irwin’s brain. Irwin has spent much of his adult life addicted to smoking methamphetamine – or P, as the drug is known in New Zealand. He knows its effects intimately: the euphoria, the paranoia, the explosive violence, the energy, the tics that run through his neck and lips. Stepping outside the MRI machine, however, he can get a fresh view for the first time – looking in from the outside at what the drug has done to his internal organs. New Zealanders are some of the world’s biggest meth takers: wastewater testing has placed it in the top four consumers worldwide. The country’s physical isolation – 4,000km from the nearest major ports – makes importing hard drugs challenging and costly, but meth can be manufactured relatively cheaply and easily, and is derived from available pharmaceuticals. Almost a third of middle-aged New Zealanders have tried the drug, a University of Otago study found in 2020. In the backroom of Mātai research centre, Irwin thinks back to when it all started. He was a teenager when he tried P for the first time – trying to impress a girl on New Year’s Eve, in his home town of Porirua, Wellington. The girlfriend didn’t last, but the drug was love at first puff, he says, and would become one of the defining relationships of his life. “I remember it was the next day, the sun had risen, I was still awake with the people at the table I’d been smoking with. And I was instantly trying to find ways: how can we make money to get more?” Within a few years, he would be smoking every day. © 2023 Guardian News & Media Limited

Keyword: Drug Abuse; Brain imaging
Link ID: 28772 - Posted: 05.06.2023

By Laura Sanders Like Dumbledore’s wand, a scan can pull long strings of stories straight out of a person’s brain — but only if that person cooperates. This “mind-reading” feat, described May 1 in Nature Neuroscience, has a long way to go before it can be used outside of sophisticated laboratories. But the result could ultimately lead to seamless devices that help people who can’t talk or otherwise communicate easily. The research also raises privacy concerns about unwelcome neural eavesdropping (SN: 2/11/21). “I thought it was fascinating,” says Gopala Anumanchipalli, a neural engineer at the University of California, Berkeley who wasn’t involved in the study. “It’s like, ‘Wow, now we are here already,’” he says. “I was delighted to see this.” As opposed to implanted devices that have shown recent promise, the new system requires no surgery (SN: 11/15/22). And unlike other external approaches, it produces continuous streams of words instead of having a more constrained vocabulary. For the new study, three people lay inside a bulky MRI machine for at least 16 hours each. They listened to stories, mostly from The Moth podcast, while functional MRI scans detected changes in blood flow in the brain. These changes are proxies for brain activity, albeit slow and imperfect measures. With this neural data in hand, computational neuroscientists Alexander Huth and Jerry Tang of the University of Texas at Austin and colleagues were able to match patterns of brain activity to certain words and ideas. The approach relied on a language model that was built with GPT, one of the forerunners that enabled today’s AI chatbots (SN: 4/12/23). © Society for Science & the Public 2000–2023.

Keyword: Brain imaging; Consciousness
Link ID: 28769 - Posted: 05.03.2023

By Oliver Whang Think of the words whirling around in your head: that tasteless joke you wisely kept to yourself at dinner; your unvoiced impression of your best friend’s new partner. Now imagine that someone could listen in. On Monday, scientists from the University of Texas, Austin, made another step in that direction. In a study published in the journal Nature Neuroscience, the researchers described an A.I. that could translate the private thoughts of human subjects by analyzing fMRI scans, which measure the flow of blood to different regions in the brain. Already, researchers have developed language-decoding methods to pick up the attempted speech of people who have lost the ability to speak, and to allow paralyzed people to write while just thinking of writing. But the new language decoder is one of the first to not rely on implants. In the study, it was able to turn a person’s imagined speech into actual speech and, when subjects were shown silent films, it could generate relatively accurate descriptions of what was happening onscreen. “This isn’t just a language stimulus,” said Alexander Huth, a neuroscientist at the university who helped lead the research. “We’re getting at meaning, something about the idea of what’s happening. And the fact that that’s possible is very exciting.” The study centered on three participants, who came to Dr. Huth’s lab for 16 hours over several days to listen to “The Moth” and other narrative podcasts. As they listened, an fMRI scanner recorded the blood oxygenation levels in parts of their brains. The researchers then used a large language model to match patterns in the brain activity to the words and phrases that the participants had heard. © 2023 The New York Times Company

Keyword: Brain imaging; Consciousness
Link ID: 28768 - Posted: 05.03.2023

Sara Reardon The little voice inside your head can now be decoded by a brain scanner — at least some of the time. Researchers have developed the first non-invasive method of determining the gist of imagined speech, presenting a possible communication outlet for people who cannot talk. But how close is the technology — which is currently only moderately accurate — to achieving true mind-reading? And how can policymakers ensure that such developments are not misused? Most existing thought-to-speech technologies use brain implants that monitor activity in a person’s motor cortex and predict the words that the lips are trying to form. To understand the actual meaning behind the thought, computer scientists Alexander Huth and Jerry Tang at the University of Texas at Austin and their colleagues combined functional magnetic resonance imaging (fMRI), a non-invasive means of measuring brain activity, with artificial intelligence (AI) algorithms called large language models (LLMs), which underlie tools such as ChatGPT and are trained to predict the next word in a piece of text. In a study published in Nature Neuroscience on 1 May, the researchers had 3 volunteers lie in an fMRI scanner and recorded the individuals’ brain activity while they listened to 16 hours of podcasts each1. By measuring the blood flow through the volunteers’ brains and integrating this information with details of the stories they were listening to and the LLM’s ability to understand how words relate to one another, the researchers developed an encoded map of how each individual’s brain responds to different words and phrases. Next, the researchers recorded the participants’ fMRI activity while they listened to a story, imagined telling a story or watched a film that contained no dialogue. Using a combination of the patterns they had previously encoded for each individual and algorithms that determine how a sentence is likely to be constructed based on other words in it, the researchers attempted to decode this new brain activity. The video below shows the sentences produced from brain recordings taken while a study participant watched a clip from the animated film Sintel about a girl caring for a baby dragon. © 2023 Springer Nature Limited

Keyword: Brain imaging; Consciousness
Link ID: 28767 - Posted: 05.03.2023

By McKenzie Prillaman Cracking the code to brain cancer treatment might start with cracking the brain’s protective shield. Nearly impenetrable walls of jam-packed cells line most of the brain’s blood vessels. Although this blood-brain barrier protects the organ from harmful invaders, it also prevents many medications from reaching the brain. Now, scientists can get a powerful chemotherapy drug into the human brain by temporarily opening its protective shield with ultrasound and tiny bubbles. The early-stage clinical trial, described May 2 in the Lancet Oncology, could lead to new treatments for those with brain cancer. Better treatments are especially needed for glioblastoma, a common and aggressive type of brain tumor. Even after surgical removal, another mass tends to grow in its place. “There’s really no established treatment for when the tumors come back,” says neurosurgeon Adam Sonabend of the Northwestern University Feinberg School of Medicine in Chicago. Patients with recurrent glioblastomas “don’t have any meaningful therapeutic options, so we were exploring new ways of treating them.” After the initial tumor has been removed, patients typically receive a relatively weak chemotherapy drug that can bypass the brain’s barricade. More potent drugs could help destroy any lingering disease — if the medicines could break through the barrier. © Society for Science & the Public 2000–2023.

Keyword: Brain imaging
Link ID: 28763 - Posted: 05.03.2023

By Nora Bradford The classical view of how the human brain controls voluntary movement might not tell the whole story. That map of the primary motor cortex — the motor homunculus — shows how this brain region is divided into sections assigned to each body part that can be controlled voluntarily (SN: 6/16/15). It puts your toes next to your ankle, and your neck next to your thumb. The space each part takes up on the cortex is also proportional to how much control one has over that part. Each finger, for example, takes up more space than a whole thigh. A new map reveals that in addition to having regions devoted to specific body parts, three newfound areas control integrative, whole-body actions. And representations of where specific body parts fall on this map are organized differently than previously thought, researchers report April 19 in Nature. Research in monkeys had hinted at this. “There is a whole cohort of people who have known for 50 years that the homunculus isn’t quite right,” says Evan Gordon, a neuroscientist at Washington University School of Medicine in St. Louis. But ever since pioneering brain-mapping work by neurosurgeon Wilder Penfield starting in the 1930s, the homunculus has reigned supreme in neuroscience. Gordon and his colleagues study synchronized activity and communication between different brain regions. They noticed some spots in the primary motor cortex were linked to unexpected areas involved in action control and pain perception. Because that didn’t fit with the homunculus map, they wrote it off as a result of imperfect data. “But we kept seeing it, and it kept bugging us,” Gordon says. So the team gathered functional MRI data on volunteers as they performed various tasks. Two participants completed simple movements like moving just their eyebrows or toes, as well as complex tasks like simultaneously rotating their wrist and moving their foot from side to side. The fMRI data revealed which parts of the brain activated at the same time as each task was done, allowing the researchers to trace which regions were functionally connected to one another. Seven more participants were recorded while not doing any particular task in order to look at how brain areas communicate during rest. © Society for Science & the Public 2000–2023.

Keyword: Brain imaging
Link ID: 28748 - Posted: 04.22.2023

Max Kozlov The bizarre-looking ‘homunculus’ is one of neuroscience’s most fundamental diagrams. Found in countless textbooks, it depicts a deformed constellation of body parts mapped onto a narrow strip of the brain, showing the corresponding brain regions that control each part. But a study published in Nature1 on 19 April reveals that this brain strip, called the primary motor cortex, is much more complex than the famous diagram suggests. It might coordinate complex movements involving multiple muscles through connections to brain regions responsible for critical thinking, maintaining the body’s physiology and planning actions. The new results could help scientists better understand and treat brain injuries. “This study is very interesting and very important,” says Michael Graziano, a neuroscientist at Princeton University in New Jersey. It’s becoming clear that the primary motor cortex isn’t “just a simple roster of muscles down the brain that control the toes to the tongue”, he says. Little man in the brain The idea of the homunculus dates to the late nineteenth century, when researchers noticed that electrically stimulating the primary motor cortex corresponded to specific body parts twitching. Later work found that some body parts, such as the hands, feet and mouth, took up a disproportionate amount of space in the primary motor cortex compared with the rest of the body. In 1937, these findings culminated with the first publication of the motor homunculus, which translates to ‘little man’ in Latin. Neurosurgeon Wilder Penfield’s 1948 diagram of the motor homunculus (left) shows the areas of the primary motor cortex that control each body part. A new study redraws the diagram (right), adding regions connected to brain areas responsible for coordinating complex movements.Credit: E. Gordon et al./Nature © 2023 Springer Nature Limited

Keyword: Brain imaging
Link ID: 28747 - Posted: 04.22.2023

BySara Reardon Anyone who’s ever owned a telescope has probably tried looking through the wrong end to see whether it works in reverse—that is, like a microscope. Spoiler alert: It doesn’t. Now, a team of researchers inspired by the strange eyes of a sea creature has figured out a way to do it. By flipping the mirrors and lenses used in certain types of telescopes, they have created a new kind of microscope that can be used to image samples floating in any type of liquid—even the insides of transparent organs—while retaining enough light to allow for high magnification. The design could help scientists achieve high enough magnification to study tiny structures such as the long, skinny axons that connect neurons in the brain or individual proteins or RNA molecules inside cells. “It’s nice to see even something as basic as a lens could still bring interest and there's still room there to do some work that would help a lot of people,” says Kimani Touissant, an electrical engineer at Brown University. He says the design could be useful in his work, in which he uses lasers to etch patterns into gels that mimic collagen and act as scaffolds for cells. At very high magnification, light trained on a sample can scatter around it, blurring and dimming the image. To get around that problem, scientists using traditional, lens-based microscopes cover their sample with a thin layer of oil or water, then dip their device’s lens into the liquid, minimizing the degree of light scattering. But this technique requires instruments to have different lenses for different types of liquid, making it an expensive, finicky process and limiting the ways that samples can be prepared. Enter Fabian Voigt, a molecular biologist at Harvard University and inventor of the new design. He was reading a book about animal vision when he encountered the odd case of scallops’ eyes. Unlike most animals, whose eyes feature retinas that send images to the brain, scallops have mantles covered with hundreds of tiny blue dots, each of which contains a curved mirror at its back. As light passes through each eye’s lens, its inner mirror reflects the light back onto the creature’s photoreceptors to create an image that then allows the scallop to respond to its environment.

Keyword: Brain imaging
Link ID: 28742 - Posted: 04.18.2023

Miryam Naddaf Virtual models representing the brains of people with epilepsy could help to enable more-effective treatments of the disease by showing neurosurgeons precisely which zones are responsible for seizures. The models, created using a computational system known as the Virtual Epileptic Patient (VEP), have been developed as part of the Human Brain Project (HBP), a ten-year European initiative focused on digital brain research. The approach is being tested in a clinical trial called EPINOV, to evaluate whether it improves the success rate of epilepsy surgery. “It’s an example of personalized medicine,” says Aswin Chari, a neurosurgeon at University College London. VEP uses “the patient’s own brain scans [and] the patient’s own brainwave-recording data to build a model and improve our understanding of where their seizures are coming from”. Life-changing surgery Epileptic seizures are brought on by abnormal brain activity, and around one-third of the 50 million people living with epilepsy worldwide do not respond to anti-seizure drugs. “For those people, surgery is a huge game changer,” says Chari. It aims to free patients from seizures by removing parts of the epileptogenic zone — the brain region that is thought to initiate seizures. To identify the epileptogenic zone, clinicians currently use scanning techniques such as magnetic resonance imaging (MRI) and electroencephalogram (EEG) to investigate brain activity. They also perform stereoelectroencephalography (SEEG), which involves placing up to 16 electrodes, each 7 centimetres long, through the skull to monitor the activity of specific areas for 1–2 weeks. © 2023 Springer Nature Limited

Keyword: Epilepsy; Brain imaging
Link ID: 28732 - Posted: 04.09.2023

By Simon Makin Waves of cerebrospinal fluid which normally wash over brains during sleep can be made to pulse in the brains of people who are wide awake, a new study finds. The clear fluid may flush out harmful waste, such as the sticky proteins that accumulate in Alzheimer’s disease (SN: 7/15/18). So being able to control the fluid’s flow in the brain could possibly one day have implications for treating certain brain disorders. “I think this [finding] will help with many neurological disorders,” says Jonathan Kipnis, a neuroscientist at Washington University in St. Louis who was not involved in the study. “Think of Formula One. You can have the best car and driver, but without a great maintenance crew, that driver will not win the race.” Spinal fluid flow in the brain is a major part of that maintenance crew, he says. But he and other researchers, including the study’s authors, caution that any potential therapeutic applications are still far off. In 2019, neuroscientist Laura Lewis of Boston University and colleagues reported that strong waves of cerebrospinal fluid wash through our brains while we slumber, suggesting that one unappreciated role of sleep may be to give the brain a deep clean (SN: 10/31/19). And the team showed that the slow neural oscillations that characterize deep, non-REM sleep occur in lockstep with the waves of spinal fluid through the brain. “If you drop your clothes in a bath of water, eventually dirt will come out. But if you swish them back and forth, things are moving much more effectively,” Lewis says. “That’s the analogy I think of.” These flows were far larger than the small, rhythmic influences that one’s breathing and heartbeat have on spinal fluid. © Society for Science & the Public 2000–2023.

Keyword: Sleep
Link ID: 28727 - Posted: 04.01.2023

Suzana Herculano-Houzel Neuroscientists have long assumed that neurons are greedy, hungry units that demand more energy when they become more active, and the circulatory system complies by providing as much blood as they require to fuel their activity. Indeed, as neuronal activity increases in response to a task, blood flow to that part of the brain increases even more than its rate of energy use, leading to a surplus. This increase is the basis of common functional imaging technology that generates colored maps of brain activity. Scientists used to interpret this apparent mismatch in blood flow and energy demand as evidence that there is no shortage of blood supply to the brain. The idea of a nonlimited supply was based on the observation that only about 40% of the oxygen delivered to each part of the brain is used – and this percentage actually drops as parts of the brain become more active. It seemed to make evolutionary sense: The brain would have evolved this faster-than-needed increase in blood flow as a safety feature that guarantees sufficient oxygen delivery at all times. Functional magnetic resonance imaging is one of several ways to measure the brain. But does blood distribution in the brain actually support a demand-based system? As a neuroscientist myself, I had previously examined a number of other assumptions about the most basic facts about brains and found that they didn’t pan out. To name a few: Human brains don’t have 100 billion neurons, though they do have the most cortical neurons of any species; the degree of folding of the cerebral cortex does not indicate how many neurons are present; and it’s not larger animals that live longer, but those with more neurons in their cortex. I believe that figuring out what determines blood supply to the brain is essential to understanding how brains work in health and disease. It’s like how cities need to figure out whether the current electrical grid will be enough to support a future population increase. Brains, like cities, only work if they have enough energy supplied. © 2010–2023, The Conversation US, Inc.

Keyword: Stroke; Brain imaging
Link ID: 28726 - Posted: 04.01.2023

By Z Paige L’Erario New Research Points to Causes for Brain Disorders with No Obvious Injury A picture of a human brain taken by a positron emission tomography scanner, also called PET scan, is seen on a screen on January 9, 2019, at the Regional and University Hospital Center of Brest in France. Credit: Fred Tanneau/Getty Images “Stop faking!” Imagine hearing those words moments after your doctor diagnosed you with, say, a stroke or a brain tumor. That sounds absurd but for many people diagnosed with a condition called functional neurological disorder (FND), this is exactly what happens. Although the disorder is not well known to many people, FND is actually one of the most common conditions that neurologists like myself encounter. In it, abnormal brain functioning causes symptoms to appear. FND comes in many forms, with symptoms that can include seizures, feelings of weakness and movement disorders. People may lose consciousness or their ability to move or walk. Or they may experience abnormal tremors or tics. It can be highly disabling and just as costly as structural neurological conditions such as amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, multiple sclerosis and Parkinson’s disease. Although men can develop FND, young to middle-aged women receive this diagnosis most frequently. And during the first two years of the COVID pandemic, FND briefly made international headlines when functional tic-like behaviors spread with social media usage, particularly among adolescent girls.

Keyword: Brain imaging; Stress
Link ID: 28725 - Posted: 04.01.2023

ByJennifer Couzin-Frankel A class of Alzheimer’s drugs that aims to slow cognitive decline, including the antibody lecanemab that was granted accelerated approval in the United States in January, can cause brain shrinkage, researchers report in a new analysis. Although scientists and drug developers have documented this loss of brain volume in clinical trial participants for years, the scientific review, published yesterday in Neurology, is the first to look at data across numerous studies. It also links the brain shrinkage to a better known side effect of the drugs, brain swelling, which often presents without symptoms. “We don’t fully know what these changes might imply,” says Jonathan Jackson, a cognitive neuroscientist at Massachusetts General Hospital. But, “These data are extremely concerning, and it’s likely these changes are detrimental.” The analysis, which found that trial participants taking these Alzheimer’s drugs often developed more brain shrinkage than when they were on a placebo, alarmed Scott Ayton, a neuroscientist at the Florey Institute of Neuroscience and Mental Health in Melbourne, Australia, who led the work. “We’re talking about the possibility of brain damage” from treatment, says Ayton, who was invited by Eisai to join an advisory board on lecanemab’s rollout in Australia if the drug is approved there. “I find it very peculiar that these data, which are very important, have been completely ignored by the field.” A spokesperson for Eisai suggested there are benign theories for the brain shrinkage, too. The company said that although participants in its pivotal trial did experience “greater cortical volume loss on lecanemab relative to placebo,” those reductions may be due to antibody clearing the protein beta amyloid from the brain, and reducing inflammation. © 2023 American Association for the Advancement of Science.

Keyword: Alzheimers; Brain imaging
Link ID: 28721 - Posted: 03.29.2023

By Allison Parshall Functional magnetic resonance imaging, or fMRI, is one of the most advanced tools for understanding how we think. As a person in an fMRI scanner completes various mental tasks, the machine produces mesmerizing and colorful images of their brain in action. Looking at someone’s brain activity this way can tell neuroscientists which brain areas a person is using but not what that individual is thinking, seeing or feeling. Researchers have been trying to crack that code for decades—and now, using artificial intelligence to crunch the numbers, they’ve been making serious progress. Two scientists in Japan recently combined fMRI data with advanced image-generating AI to translate study participants’ brain activity back into pictures that uncannily resembled the ones they viewed during the scans. The original and re-created images can be seen on the researchers’ website. “We can use these kinds of techniques to build potential brain-machine interfaces,” says Yu Takagi, a neuroscientist at Osaka University in Japan and one of the study’s authors. Such future interfaces could one day help people who currently cannot communicate, such as individuals who outwardly appear unresponsive but may still be conscious. The study was recently accepted to be presented at the 2023 Conference on The study has made waves online since it was posted as a preprint (meaning it has not yet been peer-reviewed or published) in December 2022. Online commentators have even compared the technology to “mind reading.” But that description overstates what this technology is capable of, experts say. “I don’t think we’re mind reading,” says Shailee Jain, a computational neuroscientist at the University of Texas at Austin, who was not involved in the new study. “I don’t think the technology is anywhere near to actually being useful for patients—or to being used for bad things—at the moment. But we are getting better, day by day.”

Keyword: Vision; Brain imaging
Link ID: 28708 - Posted: 03.18.2023

By McKenzie Prillaman The wiring of one insect’s brain no longer contains much uncharted territory. All of the nerve cells — and virtually every connection between them — in a larval fruit fly brain have now been mapped, researchers report in the March 10 Science. It’s the most complex whole brain wiring diagram yet created. Previously, just three organisms — a sea squirt and two types of worm — had their brain circuitry fully diagrammed to this resolution. But the brains of those creatures have only a few hundred neurons. The scientists who conducted the new study wanted to understand much more complicated brains. Fruit flies (Drosophila melanogaster) share a wide range of behaviors with humans, including integrating sensory information and learning. Larvae perform nearly all the same actions as adult flies — except for some, like flying and mating — but have smaller brains, making data collection much faster (SN: 7/19/18). The idea for this project came 12 years ago, says neuroscientist Marta Zlatic of the MRC Laboratory of Molecular Biology in Cambridge, England. At that time, she and her colleagues captured electron microscope images of the entire larval fruit fly brain. They then stitched those images together in a computer and manually traced each neuron to create a 3-D rendering of the cells. Finally, the team found the connections where information gets passed between the cells, and even determined the sending and receiving ends. Neurons transmit information to one another in circuits. Exploring the neurons’ connectivity patterns — not just directly linked partners, but also the links of linked cells and so on — revealed 93 different types of neurons. The classes were consistent with preexisting groupings characterized by shape and function. And nearly 75 percent of the most well-connected neurons were tied to the brain’s learning center, indicating the importance of learning in animals. © Society for Science & the Public 2000–2023.

Keyword: Brain imaging; Development of the Brain
Link ID: 28697 - Posted: 03.11.2023

By Eva Holland Kris Walterson doesn’t remember exactly how he got to the bathroom, very early on a Friday morning — only that once he got himself there, his feet would no longer obey him. He crouched down and tried to lift them up with his hands before sliding to the floor. He didn’t feel panicked about the problem, or even nervous really. But when he tried to get up, he kept falling down again: slamming his back against the bathtub, making a racket of cabinet doors. It didn’t make sense to him then, why his legs wouldn’t lock into place underneath him. He had a pair of fuzzy socks on, and he tried pulling them off, thinking that bare feet might get better traction on the bathroom floor. That didn’t work, either. When his mother came from her bedroom to investigate the noise, he tried to tell her that he couldn’t stand, that he needed her help. But he couldn’t seem to make her understand, and instead of hauling him up she called 911. After he was loaded into an ambulance at his home in Calgary, Alberta, a paramedic warned him that he would soon hear the sirens, and he did. The sound is one of the last things he remembers from that morning. Walterson, who was 60, was experiencing a severe ischemic stroke — the type of stroke caused by a blockage, usually a blood clot, in a blood vessel of the brain. The ischemic variety represents roughly 85 percent of all strokes. The other type, hemorrhagic stroke, is a yin to the ischemic yang: While a blockage prevents blood flow to portions of the brain, starving it of oxygen, a hemorrhage means blood is unleashed, flowing when and where it shouldn’t. In both cases, too much blood or too little, a result is the rapid death of the affected brain cells. When Walterson arrived at Foothills Medical Center, a large hospital in Calgary, he was rushed to the imaging department, where CT scans confirmed the existence and location of the clot. It was an M1 occlusion, meaning a blockage in the first and largest branch of his middle cerebral artery. © 2023 The New York Times Company

Keyword: Stroke
Link ID: 28688 - Posted: 03.04.2023

Rachel Treisman A man in southwest Florida died after becoming infected with a rare brain-eating amoeba, which state health officials say was "possibly as a result of sinus rinse practices utilizing tap water." The Florida Department of Health in Charlotte County confirmed Thursday that the unidentified man died of Naegleria fowleri. State and local health and environmental agencies "continue to coordinate on this ongoing investigation, implement protective measures, and take any necessary corrective actions," they added. The single-celled amoeba lives in warm fresh water and, once ingested through the nose, can cause a rare but almost-always fatal brain infection known as primary amebic meningoencephalitis (PAM). The Centers for Disease Control and Prevention has tallied 157 PAM infections in the U.S. between 1962 and 2022, with only four known survivors (a fifth, a Florida teenager, has been fighting for his life since last summer, according to an online fundraiser by his family). Agency data suggests this is the first such infection ever reported in February or March. Infections are most common in Southern states and during warmer months, when more people are swimming — and submerging their heads — in lakes and rivers. But they can also happen when people use contaminated tap water to rinse their sinuses, either as part of a religious ritual or an at-home cold remedy. The CDC says the disease progresses rapidly and usually causes death within about five days of symptom onset. © 2023 npr

Keyword: Neuroimmunology
Link ID: 28685 - Posted: 03.04.2023

By Rodrigo Pérez Ortega Was Tyrannosaurus rex as smart as a baboon? Scientists don’t like to compare intelligence between species (everyone has their own talents, after all), but a controversial new study suggests some dino brains were as densely packed with neurons as those of modern primates. If so, that would mean they were very smart—more than researchers previously thought—and could have achieved feats only humans and other very intelligent animals have, such as using tools. The findings, reported last week in the Journal of Comparative Neurology, are making waves among paleontologists on social media and beyond. Some are applauding the paper as a good first step toward better understanding dinosaur smarts, whereas others argue the neuron estimates are flawed, undercutting the study’s conclusions. Measuring dinosaur intelligence has never been easy. Historically, researchers have used something called the encephalization quotient (EQ), which measures an animal’s relative brain size, related to its body size. A T. rex, for example, had an EQ of about 2.4, compared with 3.1 for a German shepherd dog and 7.8 for a human—leading some to assume it was at least somewhat smart. EQ is hardly foolproof, however. In many animals, body size evolves independently from brain size, says Ashley Morhardt, a paleoneurologist at Washington University School of Medicine in St. Louis who wasn’t involved in the study. “EQ is a fraught metric, especially when studying extinct species.” Looking for a more trustworthy alternative, Suzana Herculano-Houzel, a neuroanatomist at Vanderbilt University, turned to a different measure: the density of neurons in the cortex, the wrinkly outer brain area critical to most intelligence-related tasks. She had previously estimated the number of neurons in many animal species, including humans, by making “brain soup”—dissolving brains in a detergent solution—and counting the neurons in different parts of the brain. © 2023 American Association for the Advancement of Science.

Keyword: Evolution
Link ID: 28627 - Posted: 01.12.2023

by Giorgia Guglielmi About five years ago, Catarina Seabra made a discovery that led her into uncharted scientific territory. Seabra, then a graduate student in Michael Talkowski’s lab at Harvard University, found that disrupting the autism-linked gene MBD5 affects the expression of other genes in the brains of mice and in human neurons. Among those genes, several are involved in the formation and function of primary cilia — hair-like protrusions on the cell’s surface that sense its external environment. “This got me intrigued, because up to that point, I had never heard of primary cilia in neurons,” Seabra says. She wondered if other researchers had linked cilia defects to autism-related conditions, but the scientific literature offered only sparse evidence, mostly in mice. Seabra, now a postdoctoral researcher in the lab of João Peça at the Center for Neuroscience and Cell Biology at the University of Coimbra in Portugal, is spearheading an effort to look for a connection in people: The Peça lab established a biobank of dental stem cells obtained from baby teeth of 50 children with autism or other neurodevelopmental conditions. And the team plans to look at neurons and brain organoids made from those cells to see if their cilia show any defects in structure or function. Other neuroscientists, too, are working to understand the role of cilia during neurodevelopment. Last September, for example, researchers working with tissue samples from mice discovered that cilia on the surface of neurons can form junctions, or synapses, with other neurons — which means cilia defects could, at least in theory, hinder the development of neural circuitry and activity. Other teams have connected several additional autism-related genes, beyond MBD5, to the tiny cell antennae. © 2023 Simons Foundation

Keyword: Autism
Link ID: 28623 - Posted: 01.07.2023