Chapter 2. Functional Neuroanatomy: The Cells and Structure of the Nervous System

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by Angie Voyles Askham / Brain connectivity patterns in people with autism and other neuropsychiatric conditions are more closely related to genetics than to phenotypic traits, according to two new studies. The findings highlight why a single brain biomarker for autism has remained elusive, the researchers say. The condition’s genetic heterogeneity has hampered the search for a shared brain signature: More than 100 genes have been identified as strongly linked to autism, and multiple copy number variations (CNVs) — deleted or duplicated stretches of genetic code — can increase a person’s likelihood of the condition. Autism also often overlaps with other conditions, such as schizophrenia and attention-deficit/hyperactivity disorder (ADHD), making autism-specific markers difficult to disentangle. Common variants tied to autism overlap strongly with those linked to schizophrenia and high IQ, for example, whereas rare autism-linked variants track with low IQ. According to the new papers, however, autism’s genetic heterogeneity corresponds to similarly disparate maps of ‘functional connectivity’ — a measure of which brain areas activate in sync while the brain is at rest. “What we’re seeing is that these groups of variants have specific functional connectivity signatures,” says lead investigator Sébastien Jacquemont, associate professor of pediatrics at the University of Montreal in Canada. The findings need to be replicated, says Aaron Alexander-Bloch, assistant professor of psychiatry at the University of Pennsylvania and the Children’s Hospital of Philadelphia, who was not involved in the work, but they point to the importance of subgrouping study participants based on their underlying genetics. © 2022 Simons Foundation

Keyword: Autism; Brain imaging
Link ID: 28490 - Posted: 09.28.2022

Sascha Pare Homer Simpson may not be the only one with a region of the brain dedicated to doughnuts: researchers have found that images of food appear to trigger a specific set of neurons. Previous research found that similar regions of the brain are highly specialised to identify and remember faces, places, bodies and words. The team, based at the Massachusetts Institute of Technology (MIT), say they stumbled upon the food-sensitive neurons by accident – and they could have evolved due to the evolutionary and cultural importance of food for humans. “Our most novel result is the discovery of a new neural response that has not been reported previously for the ventral visual pathway and that is highly selective for images of food,” the scientists wrote in the journal Current Biology. The researchers examined brain scans of eight participants taken as they viewed 10,000 images. Pictures of food appeared to trigger a population of neurons in the ventral visual cortex, which processes visual information. “We were quite puzzled by this because food is not a visually homogenous category,” said Meenakshi Khosla, one of the lead authors of the study. “Things like apples and corn and pasta all look so unlike each other, yet we found a single population that responds similarly to all these diverse food items.” Cooked meals such as a cheesy slice of pizza provoked a slightly stronger reactions than raw fruit and vegetables, the researchers noted. To test whether this was due to warmer colours in prepared food, they compared participants’ reactions with cool-toned images of food and richly coloured non-food objects. They found food caused a sharper signal. © 2022 Guardian News & Media Limited

Keyword: Obesity; Brain imaging
Link ID: 28452 - Posted: 08.27.2022

By Fionna M. D. Samuels, Liz Tormes Experiencing art, whether through melody or oil paint, elicits in us a range of emotions. This speaks to the innate entanglement of art and the brain: Mirror neurons can make people feel like they are physically experiencing a painting. And listening to music can change their brain chemistry. For the past 11 years, the Netherlands Institute for Neuroscience in Amsterdam has hosted the annual Art of Neuroscience Competition and explored this intersection. This year’s competition received more than 100 submissions, some created by artists inspired by neuroscience and others by neuroscientists inspired by art. The top picks explore a breadth of ideas—from the experience of losing consciousness to the importance of animal models in research—but all of them tie back to our uniquely human brain. In the moment between wakefulness and sleep, we may feel like we are losing ourself to the void of unconsciousness. This is the moment Daniela de Paulis explores with her interdisciplinary project Mare Incognito. “I always had a fascination for the moment of falling asleep,” she says. “Since I was a very small child, I always found this moment as quite transformative, also quite frightening in a way.” The winning Art of Neuroscience submission is the culmination of her project: a film that recorded de Paulis falling asleep among the silver, treelike antennas of the Square Kilometer Array at the Mullard Radio Observatory in Cambridge, England, while her brain activity was converted into radio waves and transmitted directly into space. “We combined the scientific interest with my poetic fascination in this idea of losing consciousness,” she says. In the clip above, Tristan Bekinschtein, a neuroscientist at the University of Cambridge, explains the massive change humans and their brain experience when they drift from consciousness into sleep. As someone falls asleep, their brain activity slows down in stages until they are fully out. Then bursts of activity light up their gray matter as their brain switches over to rapid eye movement (REM) sleep, and they begin to dream. © 2022 Scientific American,

Keyword: Vision; Brain imaging
Link ID: 28446 - Posted: 08.27.2022

By Eduardo Medina An infection caused by a brain-eating amoeba killed a child who swam in a Nebraska river over the weekend, health officials said Friday. It was the first such death in the state’s history and the second in the Midwest this summer. The child, whose name was not released by officials, contracted the infection, known as primary amebic meningoencephalitis, while swimming with family in a shallow part of the Elkhorn River in eastern Nebraska on Sunday, according to the Douglas County Health Department. At a news conference on Thursday, health officials said the typically fatal infection is caused by Naegleria fowleri, also known as brain-eating amoeba, and most likely led to the child’s death. The Centers for Disease Control and Prevention confirmed Friday that it had found Naegleria fowleri in the child’s cerebrospinal fluid. Last month, a person in Missouri died because of the same amoeba infection, according to the Missouri Department of Health and Senior Services. The person had been swimming at the beach at Lake of Three Fires State Park in Iowa. Out of precaution, the Iowa Department of Public Health closed the lake’s beach for about three weeks. The brain-eating amoebas, which are single-cell organisms, usually thrive in warm freshwater lakes, rivers, canals and ponds, though they can also be present in soil. They enter the body through the nose and then move into the brain. People usually become infected while swimming in lakes and rivers, according to the C.D.C. Infections from brain-eating amoeba are extremely rare: From 2012 to 2021, only 31 cases were reported in the U.S., according to the C.D.C. An infection, however, almost always leads to death. In the United States, there were 143 infections from 1962 through 2017. All but four of them were fatal, the C.D.C. said. More than half of the infections occurred in Texas and Florida, where the climate is warm and water activities are popular. © 2022 The New York Times Company

Keyword: Miscellaneous
Link ID: 28437 - Posted: 08.20.2022

Scientists know both a lot and very little about the brain. With billions of neurons and trillions of connections among them, and the experimental limitations of examining the seat of consciousness and bodily function, studying the human brain is a technical, theoretical and ethical challenge. And one of the biggest challenges is perhaps one of the most fundamental – seeing what it looks like in action. The U.S. Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative is a collaboration among the National Institutes of Health, Defense Advanced Research Projects Agency, National Science Foundation, Food and Drug Administration and Intelligence Advanced Research Projects Activity and others. Since its inception in 2013, its goal has been to develop and use new technologies to examine how each neuron and neural circuit comes together to “record, process, utilize, store, and retrieve vast quantities of information, all at the speed of thought.” Just as genomic sequencing enabled the creation of a comprehensive map of the human genome, tools that elucidate the connection between brain structure and function could help researchers answer long-standing questions about how the brain works, both in sickness and in health. These five stories from our archives cover research that has been funded by or advances the goals of the BRAIN Initiative, detailing a slice of what’s next in neuroscience. Attempts to map the structure of the brain date back to antiquity, when philosophers and scholars had only the unaided eye to map anatomy to function. New visualization techniques in the 20th century led to the discovery that, just like all the other organs of the body, the brain is composed of individual cells – neurons. © 2010–2022, The Conversation US, Inc.

Keyword: Brain imaging; Development of the Brain
Link ID: 28421 - Posted: 08.06.2022

R. Douglas Fields Neuroscientists, being interested in how brains work, naturally focus on neurons, the cells that can convey elements of sense and thought to each other via electrical impulses. But equally worthy of study is a substance that’s between them — a viscous coating on the outside of these neurons. Roughly equivalent to the cartilage in our noses and joints, the stuff clings like a fishing net to some of our neurons, inspiring the name perineuronal nets (PNNs). They’re composed of long chains of sugar molecules attached to a protein scaffolding, and they hold neurons in place, preventing them from sprouting and making new connections. Given this ability, this little-known neural coating provides answers to some of the most puzzling questions about the brain: Why do young brains absorb new information so easily? Why are the fearful memories that accompany post-traumatic stress disorder (PTSD) so difficult to forget? Why is it so hard to stop drinking after becoming dependent on alcohol? And according to new research from the neuroscientist Arkady Khoutorsky and his colleagues at McGill University, we now know that PNNs also explain why pain can develop and persist so long after a nerve injury. Neural plasticity is the ability of neural networks to change in response to experiences in life or to repair themselves after brain injury. Such opportunities for effortless change are known as critical periods when they occur early in life. Consider how easily babies pick up language, but how difficult it is to learn a foreign language as an adult. In a way, this is what we’d want: After the intricate neural networks that allow us to understand our native language are formed, it’s important for them to be locked down, so the networks remain relatively undisturbed for the rest of our lives. All Rights Reserved © 2022

Keyword: Pain & Touch; Glia
Link ID: 28415 - Posted: 07.30.2022

Bill Chappell Its name alone is terrifying. Add the fact that it kills most people it infects — and that while infections are rare, the parasite is fairly common — it's not surprising that a confirmed case of Naegleria fowleri infection in a swimmer in Iowa is drawing attention. Iowa officials closed the beach at Lake of Three Fires State Park on Thursday after confirming that a person who swam there was infected with Naegleria fowleri, an amoeba that causes a disease called primary amebic meningoencephalitis (PAM). It's both extremely rare — and extremely deadly. "The fatality rate is over 97%," the Centers for Disease Control and Prevention says of PAM infections. "Only four people out of 154 known infected individuals in the United States from 1962 to 2021 have survived." Details about the Iowa case have not yet been released. The person was visiting from Missouri, which is just over the border from the park in Iowa's southwest. Iowa's Department of Health and Human Services says it's working with the CDC to confirm whether Naegleria fowleri is present in the lake — a process that takes several days. The state agency is also in contact with the Missouri Department of Health, an Iowa representative told NPR. "It's strongly believed by public health experts that the lake is a likely source," Missouri's health department said on Friday. But it added, "Additional public water sources in Missouri are being tested." © 2022 npr

Keyword: Miscellaneous
Link ID: 28392 - Posted: 07.12.2022

By Christina Caron In recent years, the vagus nerve has become an object of fascination, especially on social media. The vagal nerve fibers, which run from the brain to the abdomen, have been anointed by some influencers as the key to reducing anxiety, regulating the nervous system and helping the body to relax. TikTok videos with the hashtag “#vagusnerve” have been viewed more than 64 million times and there are nearly 70,000 posts with the hashtag on Instagram. Some of the most popular ones feature simple hacks to “tone” or “reset” the vagus nerve, in which people plunge their faces into ice water baths or lie on their backs with ice packs on their chests. There are also neck and ear massages, eye exercises and deep-breathing techniques. Now, wellness companies have capitalized on the trend, offering products like “vagus massage oil,” vibrating bracelets and pillow mists, that claim to stimulate the nerve, but that have not been endorsed by the scientific community. Researchers who study the vagus nerve say that stimulating it with electrodes can potentially help improve mood and alleviate symptoms in those who suffer from treatment-resistant depression, among other ailments. But are there other ways to activate the vagus nerve? Who would benefit most from doing so? And what exactly is the vagus nerve, anyway? Here’s a look at what we know so far. The term “vagus nerve” is actually shorthand for thousands of fibers. They are organized into two bundles that run from the brain stem down through each side of the neck and into the torso, branching outward to touch our internal organs, said Dr. Kevin J. Tracey, a neurosurgeon and president of the Feinstein Institutes for Medical Research, Northwell Health’s research center in New York. Imagine something akin to a tree, whose limbs interact with nearly every organ system in the body. (The word “vagus” means “wandering” in Latin.) The vagus nerve picks up information about how the organs are functioning and also sends information from the brain stem back to the body, helping to control digestion, heart rate, voice, mood and the immune system. For those reasons, the vagus nerve — the longest of the 12 cranial nerves — is sometimes referred to as an “information superhighway.” Dr. Tracey compared it to a trans-Atlantic cable. “It’s not a mishmash of signals,” he said. “Every signal has a specific job.” © 2022 The New York Times Company

Keyword: Depression; Stress
Link ID: 28361 - Posted: 06.09.2022

by Rachel Zamzow Inflammation may inflate or thin out brain regions tied to autism and schizophrenia, researchers report in a new study. The findings add nuance to the long-held hypothesis that immune activation elevates the risk for neurodevelopmental conditions. Autism, for example, is associated with prenatal exposure to infection, previous studies show. Taking a different approach, the new work focuses on how a genetic predisposition to inflammation affects brain development in the general population, says John Williams, research fellow at the University of Birmingham in the United Kingdom, who conducted the work with lead researcher Rachel Upthegrove, professor of psychiatry and youth mental health at the university. By pinpointing where inflammation leaves its mark in the brain, the findings serve as a guidepost for future studies of people with neuropsychiatric conditions, he says. “We think that it points to something that’s fairly transdiagnostic.” For their analyses, the team drew on brain imaging and genetic data from 10,828 women and 9,860 men in the general population who participated in the UK Biobank. They explored how 1,436 possible structural changes in the brain track with having single-nucleotide variants previously shown to increase circulating levels of five inflammatory molecules — interleukin 1 (IL-1), IL-2, IL-6, C-reactive protein and brain-derived neurotrophic factor. Three variants thought to boost IL-6 were associated with 33 structural changes, most notably increased volume in the middle temporal gyrus and fusiform gyrus, and decreased cortical thickness in the superior frontal gyrus — all brain areas implicated in autism. Variants associated with other inflammatory molecules did not track with brain changes, the researchers found. © 2022 Simons Foundation

Keyword: Autism; Genes & Behavior
Link ID: 28317 - Posted: 05.07.2022

By Monique Brouillette Neuroscientists have long aspired to understand the intangible properties of the mind. Our most treasured cerebral qualities, like the ability to think, write poetry, fall in love and even envision a higher spiritual realm, are all generated in the brain. But how the squishy, pinkish-gray, wrinkled mass of the physical brain gives rise to these impalpable experiences remains a mystery. Some neuroscientists think the key to cracking that mystery is a better map of the brain’s circuitry. Nearly 40 years ago, scientists achieved a milestone by completing a wiring diagram that traced all the connections of the 302 neurons of the roundworm Caenorhabditis elegans. They were traced by hand on printed sheets of electron microscope images, a meticulous and herculean task that took years to complete. The project marked the first-ever complete connectome — a comprehensive map of the neuronal connections in an animal’s nervous system. Today, thanks to advances in computing and image analysis algorithms, it can take less than a month to map a roundworm’s connectome. These technological improvements mean that scientists can set their sights on larger animals. They are closing in on the connectome of fruit fly larvae, with more than 9,000 cells, and adult flies, with 100,000 neurons. Next, they hope to map the brain of a developing fish and, perhaps within the next decade, a mouse, with roughly 70 million neurons — a project nearly a thousand times more ambitious than any done so far. And they have already started to map small pieces of the human brain, an unfathomable quest when the worm connectome was initially mapped. © 2022 Annual Reviews

Keyword: Brain imaging
Link ID: 28308 - Posted: 04.30.2022

By Katharine Q. Seelye Ursula Bellugi, a pioneer in the study of the biological foundations of language who was among the first to demonstrate that sign language was just as complex, abstract and systematic as spoken language, died on Sunday in San Diego. She was 91. Her death, at an assisted living facility, was confirmed by her son Rob Klima. Dr. Bellugi was a leading researcher at the Salk Institute for Biological Studies in San Diego for nearly five decades and, for much of that time, was director of its laboratory for cognitive neuroscience. She made significant contributions in three main areas: the development of language in children; the linguistic structure and neurological basis of American Sign Language; and the social behavior and language abilities of people with a rare genetic disorder, Williams syndrome. “She leaves an indelible legacy of shedding light on how humans communicate and socialize with each other,” Rusty Gage, president of the Salk Institute, said in a statement. Dr. Bellugi’s work, much of it done in collaboration with her husband, Edward S. Klima, advanced understanding of the brain and the origins of language, both signed and spoken. American Sign Language was first described as a true language in 1960 by William C. Stokoe Jr., a professor at Gallaudet University, the world’s only liberal arts university devoted to deaf people. But he was ridiculed and attacked for that claim. Dr. Bellugi and Dr. Klima, who died in 2008, demonstrated conclusively that the world’s signed languages — of which there are more than 100 — were actual languages in their own right, not just translations of spoken languages. Dr. Bellugi, who focused on American Sign Language, established that these linguistic systems were passed down, in all their complexity, from one generation of deaf people to the next. For that reason, the scientific community regards her as the founder of the neurobiology of American Sign Language. The couple’s work led to a major discovery at the Salk lab: that the left hemisphere of the brain has an innate predisposition for language, whether spoken or signed. That finding gave scientists fresh insight into how the brain learns, interprets and forgets language. © 2022 The New York Times Company

Keyword: Language; Laterality
Link ID: 28296 - Posted: 04.23.2022

By Kim Tingley In March, neuroscientists and psychiatrists from the School of Medicine at Washington University, St. Louis, along with colleagues elsewhere, published a study in the journal Nature that sparked widespread discussion in their fields. Researchers, the study noted, are increasingly using magnetic resonance imaging — which can reveal the brain’s structure and activity — to try to find links between what is seen on an M.R.I., like cortical thickness or patterns of connection, and complicated psychological traits, like cognitive ability or mental-health conditions. In theory, such so-called brain-wide association studies could yield incredibly valuable insights. Knowing that a particular neurological feature makes someone more vulnerable to autism, Alzheimer’s or another disorder, for example, could help predict, prevent or treat that condition. Likewise, if we can link certain features to desirable traits, like academic achievement, it might be possible to take advantage of that knowledge. The problem, the Nature authors argued, is that neuroscientists often are searching for those associations in groups of study subjects that are too small, leading to results that are statistically “underpowered.” In general, they calculated, thousands of subjects should be included for a brain-wide association study to produce a finding that other studies can replicate. This was unwelcome news to many, in large part because M.R.I. machines are incredibly expensive to use, often at about $1,000 per hour, and funding is limited. Specific instances of underpowered studies are legion. So much so, says Terry Jernigan, director of the Center for Human Development at the University of California, San Diego, that singling out an example “would simply be unfair.” Indeed, according to a paper from 2020 in NeuroImage, the average number of study subjects in more than a thousand of the most cited brain-imaging papers, published between 1990 and 2012, was 12; the Nature paper calculated that the median sample size for neuroimaging studies uploaded to a popular open-access platform as of September 2021 was 23. © 2022 The New York Times Company

Keyword: Brain imaging
Link ID: 28294 - Posted: 04.20.2022

by Niko McCarty A new miniature, head-mounted microscope can simultaneously record the activity of thousands of neurons at different depths within the brains of freely moving mice. The smallest functional two-photon microscope to date, it can image neurons almost anywhere in the brain, with subcellular resolution. The device, called MINI2P (miniature two-photon microscope), can also collect data from the same cluster of neurons over several weeks, making it useful for long-term behavioral studies. “If you really want to understand what is behind cognition or failures in cognition, like in autism, you need to look at the interaction between neurons,” says lead investigator Edvard Moser, professor of neuroscience at the Kavli Institute for Systems Neuroscience in Trondheim, Norway. Other devices that measure neuronal activity, such as Neuropixels 2.0, record signals from more than 10,000 sites in the brain at once. But they have a low spatial resolution and cannot always determine which specific neuron is firing at any given time. Other miniature microscopes have also, traditionally, relied on visible light, which illuminates the surface of tissue, but are limited to imaging about 2,000 neurons. The new device can monitor a brain area measuring 500 by 500 micrometers and can capture data on more than 10,000 neurons at once. A typical mouse brain is roughly the size of a pea and contains about 85 million neurons. The MINI2P uses infrared light to capture the activity of neurons engineered to express GCaMP, a protein that binds to calcium ions during an action potential and emits a fluorescent signal in reply. The microscope measures that fluorescence using an infrared laser beam. © 2022 Simons Foundation

Keyword: Brain imaging
Link ID: 28282 - Posted: 04.13.2022

By Benjamin Ehrlich Hour after hour, year after year, Santiago Ramón y Cajal sat alone in his home laboratory, head bowed and back hunched, his black eyes staring down the barrel of a microscope, the sole object tethering him to the outside world. His wide forehead and aquiline nose gave him the look of a distinguished, almost regal, gentleman, although the crown of his head was as bald as a monk’s. He had only a crowd of glass bottles for an audience, some short and stout, some tall and thin, stopped with cork and filled with white powders and colored liquids; the other chairs, piled high with journals and textbooks, left no room for anyone else to sit. Stained with dye, ink and blood, the tablecloth was strewn with drawings of forms at once otherworldly and natural. Colorful transparent slides, mounted with slivers of nervous tissue from sacrificed animals still gummy to the touch from chemical treatments, lay scattered on the worktable. With his left thumb and forefinger, Cajal adjusted the corners of the slide as if it were a miniature picture frame under the lens of his microscope. With his right hand, he turned the brass knob on the side of the instrument, muttering to himself as he drew the image into focus: brownish-black bodies resembling inkblots and radiating threadlike appendages set against a transparent yellow background. The wondrous landscape of the brain was finally revealed to him, more real than he could have ever imagined. In the late 19th century most scientists believed the brain was composed of a continuous tangle of fibers as serpentine as a labyrinth. Cajal produced the first clear evidence that the brain is composed of individual cells, later termed neurons, that are fundamentally the same as those that make up the rest of the living world. He believed that neurons served as storage units for mental impressions such as thoughts and sensations, which combined to form our experience of being alive: “To know the brain is equivalent to ascertaining the material course of thought and will,” he wrote. The highest ideal for a biologist, he declared, is to clarify the enigma of the self. In the structure of neurons, Cajal thought he had found the home of consciousness itself. © 2022 Scientific American

Keyword: Brain imaging
Link ID: 28278 - Posted: 04.13.2022

Max Kozlov When neuroscientist Jakob Seidlitz took his 15-month-old son to the paediatrician for a check-up last week, he left feeling unsatisfied. There wasn’t anything wrong with his son — the youngster seemed to be developing at a typical pace, according to the height and weight charts the physician used. What Seidlitz felt was missing was an equivalent metric to gauge how his son’s brain was growing. “It is shocking how little biological information doctors have about this critical organ,” says Seidlitz, who is based at the University of Pennsylvania in Philadelphia. Soon, he might be able to change that. Working with colleagues, Seidlitz has amassed more than 120,000 brain scans — the largest collection of its kind — to create the first comprehensive growth charts for brain development. The charts show visually how human brains expand quickly early in life and then shrink slowly with age. The sheer magnitude of the study, published in Nature on 6 April1, has stunned neuroscientists, who have long had to contend with reproducibility issues in their research, in part because of small sample sizes. Magnetic resonance imaging (MRI) is expensive, meaning that scientists are often limited in the number of participants they can enrol in experiments. “The massive data set they assembled is extremely impressive and really sets a new standard for the field,” says Angela Laird, a cognitive neuroscientist at Florida International University in Miami. Even so, the authors caution that their database isn’t completely inclusive — they struggled to gather brain scans from all regions of the globe. The resulting charts, they say, are therefore just a first draft, and further tweaks would be needed to deploy them in clinical settings. If the charts are eventually rolled out to paediatricians, great care will be needed to ensure that they are not misinterpreted, says Hannah Tully, a paediatric neurologist at the University of Washington in Seattle. “A big brain is not necessarily a well-functioning brain,” she says. © 2022 Springer Nature Limited

Keyword: Development of the Brain; Brain imaging
Link ID: 28277 - Posted: 04.09.2022

Linda Geddes A completely locked-in patient is able to type out words and short sentences to his family, including what he would like to eat, after being implanted with a device that enables him to control a keyboard with his mind. The findings, published in Nature Communications, overturn previous assumptions about the communicative abilities of people who have lost all voluntary muscle control, including movement of the eyes or mouth, as well as giving a unique insight into what it’s like to be in a “locked in” state. Locked-in syndrome – also known as pseudocoma - is a rare condition, where people are conscious and can see, hear, and smell, but are unable to move or speak due to complete paralysis of their voluntary muscles, eg as a result of the progressive neurodegenerative disease amyotrophic lateral sclerosis (ALS). Advertisement Some can communicate by blinking or moving their eyes, but those with completely locked-in syndrome (CLIS) cannot even control their eye muscles. In 2017, doctors at the University of Tübingen in Germany enabled three patients with CLIS to answer “yes” or “no” to questions by detecting telltale patterns in their brain activity, using a technology called functional near-infrared spectroscopy (fNIRS). The advance generated widespread media coverage, and prompted the parents of the current patient, who was diagnosed with ALS in 2015, to write to the medical team, saying he was losing the ability to communicate with his eye movements, and could they help. The problem with using fNIRS to help CLIS patients to communicate is that it is relatively slow, and only gives the correct answer 70% of the time, meaning questions have to be repeated to get a reliable answer. “It was always our goal to enable a patient in a completely locked down state to spell out words, but with a classification accuracy of 70%, it is almost impossible to enable free spelling,” said Dr Ujwal Chaudhary, a biomedical engineer and managing director of ALS Voice gGmbH in Mössingen, Germany, who co-led the research. © 2022 Guardian News & Media Limited

Keyword: ALS-Lou Gehrig's Disease ; Movement Disorders
Link ID: 28250 - Posted: 03.23.2022

By Matt Richtel For two decades, researchers have used brain-imaging technology to try to identify how the structure and function of a person’s brain connects to a range of mental-health ailments, from anxiety and depression to suicidal tendencies. But a new paper, published Wednesday in Nature, calls into question whether much of this research is actually yielding valid findings. Many such studies, the paper’s authors found, tend to include fewer than two dozen participants, far shy of the number needed to generate reliable results. “You need thousands of individuals,” said Scott Marek, a psychiatric researcher at the Washington University School of Medicine in St. Louis and an author of the paper. He described the finding as a “gut punch” for the typical studies that use imaging to try to better understand mental health. Studies that use magnetic-resonance imaging technology commonly temper their conclusions with a cautionary statement noting the small sample size. But enlisting participants can be time-consuming and expensive, ranging from $600 to $2,000 an hour, said Dr. Nico Dosenbach, a neurologist at Washington University School of Medicine and another author on the paper. The median number of subjects in mental-health-related studies that use brain imaging is around 23, he added. But the Nature paper demonstrates that the data drawn from just two dozen subjects is generally insufficient to be reliable and can in fact yield “massively inflated” findings,” Dr. Dosenbach said. For their analysis, the researchers examined three of the largest studies using brain-imaging technology to reach conclusions about brain structure and mental health. All three studies are ongoing: the Human Connectome Project, which has 1,200 participants; the Adolescent Brain Cognitive Development, or A.B.C.D., study, with 12,000 participants; and the U.K. Biobank study, with 35,700 participants. The authors of the Nature paper looked at subsets of data within those three studies to determine whether smaller slices were misleading or “reproducible,” meaning that the findings could be considered scientifically valid. © 2022 The New York Times Company

Keyword: Brain imaging
Link ID: 28245 - Posted: 03.19.2022

by Niko McCarty The ‘opto’ in optogenetics — the powerful method some autism researchers use to control neurons in mice and other animals — comes from the Greek optós, meaning visible. It’s a nod to the blue light used to switch on select neurons. A new technique can do the same, albeit with something invisible: sound. In a study published in Nature Communications this month, researchers engineered neurons in the motor cortex of mice to express an ultrasound-sensitive ion channel protein called hsTRPA1. They placed an ultrasound transducer near the animal’s skull and switched it on. The response? A flex of a muscle, a perceptible twitch. The approach, called sonogenetics, enables noninvasive control over any neural circuit that can be manipulated with optogenetics, an invasive method, says lead investigator Sreekanth Chalasani, associate professor in the Molecular Neurobiology Laboratory at the Salk Institute for Biological Studies in La Jolla, California. Spectrum spoke to Chalasani about his early experiments in Caenorhabditis elegans, lucky number 63 and how sonogenetics could one day have clinical applications. Spectrum: Our readers might be familiar with optogenetics, but I’m assuming sonogenetics is new for most people. Sreekanth Chalasani: Yeah. Well, the idea in sonogenetics is that we want to manipulate things noninvasively. Ultrasound can travel through bone and skin, into the body. We’ve been using it for decades. It’s safe. The question is: Can we leverage it to get in the body and control cells, like with optogenetics? S: Literally controlling cells with sound. SC: Right. In optogenetics, light triggers action potentials in cells that have a channelrhodopsin, or opsin, protein. In sonogenetics, we wanted a protein that would let us have that same level of cellular control. But finding that protein has been difficult. Lots of groups have been looking for these proteins, and we were fortunate to find one. © 2022 Simons Foundation

Keyword: Brain imaging
Link ID: 28227 - Posted: 03.02.2022

Natalia Mesa More than a decade ago, scientists developed optogenetics, a method to turn cells on and off with light. The technique allows scientists to spur or suppress cells' electrical activity with just the flip of a switch to tease apart the roles of specific cell types. But because light doesn’t penetrate deep into tissues, scientists need to surgically implant light sources to illuminate cells below the surface of the skin or skull. In a new study published today (February 9) in Nature Communications, researchers report they’ve found a way to use ultrasound to noninvasively activate mouse neurons, both in culture and in the brains of living animals. The technique, which the authors call sonogenetics, elicits electrical activity in a subset of brain cells that have been genetically engineered to respond to sound waves. “We know that ultrasound is safe,” study coauthor Sreekanth Chalasani, a neuroscientist in Salk’s Molecular Neurobiology Laboratory, tells The Scientist. “The potential for neuronal control is huge. It has applications for pacemakers, insulin pumps, and other therapies that we’re not even thinking about. Jamie Tyler, a biomedical engineer at the University of Alabama at Birmingham who was not involved in the study but has previously collaborated with some of its authors, tells The Scientist that the work represents “more than just a step forward” in being able to use ultrasound to control neural activity: “It shows that sonogenetics is a viable technique in mammalian cells.” © 1986–2022 The Scientist.

Keyword: Brain imaging
Link ID: 28199 - Posted: 02.12.2022

In 2016, Science magazine ranked Randy L. Buckner among the top 10 most influential brain scientists of the modern era. He explains the road to discovering the default network, the pattern of brain activity triggered as we think about the past and the future. Q: Why don’t we begin with a brief description of what the default network is, how and when it was discovered, and why it’s important. Randy L. Buckner: In the 1990s, neuroscientists were just starting to do functional imaging studies. For the first time, we had brain scanners that could see the mind at work. We were like kids in a candy store in the sense that we no longer needed a scalpel to see the brain; the new technology allowed us to safely discern information out about what parts of the brain people used when given different tasks and different kinds of visual or auditory stimuli. I was a graduate student at the time at Washington University and one of my mentors, Marcus Raichle, was at the forefront of positron emission tomography (PET), an imaging technique that measures physiological changes in the brain and shows where blood flow is increasing due to brain activity. This is when many of us first became aware of the Dana Foundation, which was helping fund our work. I was a Dana fellow in those early days, and this was an exciting time in neuroscience. In early studies, we often asked participants to perform very simple tasks: read and say words, detect colors in pictures, or try to recognize whether a viewed word was on an earlier studied list. The imaging revealed the parts of the brain involved in their responses. But what jumped out at us was something unexpected: When people weren’t asked for a response or given a specific task, much of their brain still remained active. © 2022 The Dana Foundation.

Keyword: Brain imaging
Link ID: 28171 - Posted: 01.26.2022