Chapter 1. Cells and Structures: The Anatomy of the Nervous System

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


Links 61 - 80 of 1299

By Pallab Ghosh Science correspondent, BBC News, Seattle US researchers are developing a better understanding of the human brain by studying tissue left over from surgery. They say that their research is more likely to lead to new treatments than studies based on mouse and rat models. Dr Ed Lein, who leads the initiative at the Allen Institute has set up a scheme with local doctors to study left over tissue just hours after surgery. He gave details at the American Association for the Advancement of Science meeting in Seattle. "It is a little bit crazy that we have such a huge field where we are trying to solve brain diseases and there is very little understanding of the human brain itself," said Dr Lein. "The field as a whole is largely assuming that the human brain is similar to those of animal models without ever testing that view. "But the mouse brain is a thousand times smaller, and any time people look, they find significant differences." Dr Lein and his colleagues at the Allen Institute in Seattle set up the scheme with local neurosurgeons to study brain tissue just hours after surgery - with the consent of the patient. It functions as if it is still inside the brain for up to 48 hours after it has been removed. So Dr Lein and his colleagues have to drop everything and often have to work through the night once they hear that brain tissue has become available. © 2020 BBC

Keyword: Brain imaging; Epilepsy
Link ID: 27040 - Posted: 02.14.2020

By Veronique Greenwood When you look at a reconstruction of the skull and brain of Neoepiblema acreensis, an extinct rodent, it’s hard to shake the feeling that something’s not quite right. Huddled at the back of the cavernous skull, the brain of the South American giant rodent looks really, really small. By some estimates, it was around three to five times smaller than scientists would expect from the animal’s estimated body weight of about 180 pounds, and from comparisons to modern rodents. In fact, 10 million years ago the animal may have been running around with a brain weighing half as much as a mandarin orange, according to a paper published Wednesday in Biology Letters. The glory days of rodents, in terms of the animals’ size, were quite a long time ago, said Leonardo Kerber, a paleontologist at Universidade Federal de Santa Maria in Brazil and an author of the new study. Today rodents are generally dainty, with the exception of larger creatures like the capybara that can weigh as much as 150 pounds. But when it comes to relative brain size, N. acreensis, represented in this study by a fossil skull unearthed in the 1990s in the Brazilian Amazon, seems to be an extreme. The researchers used an equation that relates the body and brain weight of modern South American rodents to get a ballpark estimate for N. acreensis, then compared that with the brain weight implied by the volume of the cavity in the skull. The first method predicted a brain weighing about 4 ounces, but the volume suggested a dinky 1.7 ounces. Other calculations, used to compare the expected ratio of the rodent’s brain and body size with the actual fossil, suggested that N. acreensis’ brain was three to five times smaller than one would expect. © 2020 The New York Times Company

Keyword: Evolution; Brain imaging
Link ID: 27035 - Posted: 02.13.2020

By Kelly Servick Since its launch in 2013, the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative has doled out about $1.3 billion in grants to develop tools that map and manipulate the brain. Until now, it has operated with no formal director. But last week, the National Institutes of Health (NIH), which manages the initiative and is a key funder, announced that neurobiologist John Ngai would take the helm starting in March. Ngai, whose lab at the University of California, Berkeley, focuses on the neural underpinnings of the sense of smell, has helped lead BRAIN-funded efforts to classify the brain’s dizzying array of cell types with RNA sequencing. Ngai told ScienceInsider about how the initiative is evolving and how he hopes to influence it. The interview has been edited for clarity and brevity. Q: Why is the BRAIN Initiative getting a director now? A: The initiative has been run day to day by a terrific team of senior program directors and staff with oversight from the 10 NIH institutes and centers that are involved in BRAIN. Walter Koroshetz [director of the National Institute of Neurological Disorders and Stroke] and Josh Gordon [director of the National Institute of Mental Health] have been overseeing the activities of BRAIN … kind of in addition to their “day jobs.” I think as enterprises emerge from their startup phase, which is typically the first 5 years, the question is how do you translate this into a sustainable enterprise, and yet maintain this cutting-edge innovation? … How do we leverage all the accomplishments that have been made, not just within BRAIN, but in molecular biology, in engineering, in chemistry and computer science, in data science. The initiative really will benefit from somebody thinking about this 24/7. © 2019 American Association for the Advancement of Science.

Keyword: Brain imaging; Chemical Senses (Smell & Taste)
Link ID: 27020 - Posted: 02.05.2020

Timothy Bella The headaches had become so splitting for Gerardo Moctezuma that the pain caused him to vomit violently. The drowsiness that came with it had intensified for months. But it wasn’t until Moctezuma, 40, fainted without explanation at a soccer match in Central Texas last year that he decided to figure out what was going on. When Jordan Amadio looked down at his MRI results, the neurosurgeon recognized — but almost couldn’t believe — what looked to be lodged in Moctezuma’s brain. As he opened up Moctezuma’s skull during an emergency surgery in May 2019, he was able to confirm what it was that had uncomfortably set up shop next to the man’s brain stem: a tapeworm measuring about an inch-and-a-half. “It’s very intense, very strong, because it made me sweat too, sweat from the pain,” Moctezuma said to KXAN. The clear and white parasite came from tapeworm larva that Amadio believes Moctezuma, who moved from Mexico to the U.S. 14 years before his diagnosis, might have had in his brain for more than a decade undetected. His neurological symptoms had intensified due to his neurocysticercosis, which was the direct result of the tapeworm living in his brain. The cyst would trigger hydrocephalus, an accumulation of cerebrospinal fluid that increased pressure to the skull to the point that the blockage and pain had become life-threatening. “It’s a remarkable case where a patient came in and, if he had not been treated urgently, he would have died from tremendous pressure in the brain,” Amadio, attending neurosurgeon at the Ascension Seton Brain and Spine Institute in Austin, told The Washington Post on Thursday night.

Keyword: Development of the Brain
Link ID: 27013 - Posted: 02.01.2020

Abby Olena Understanding the array of neural signals that occur as an organism makes a decision is a challenge. To tackle it, the authors of a study published last week (January 16) in Cell imaged large swaths of the larval zebrafish brain as the animals decided which way to move their tails to avoid an undesirable situation. Finding patterns in the data, they were then able to use imaging to predict—10 seconds in advance—the timing and direction of the fish’s movement. “In a lot of other model systems it’s really difficult to actually . . . record something that’s happening throughout the whole brain with a high level of precision,” says Kristen Severi, a biologist at the New Jersey Institute of Technology who was not involved in the study. “When you have something like a larval zebrafish where you have access to the entire brain with single-cell resolution in a transparent vertebrate, it’s a great place to start to try to look for activity patterns that might be distributed and might be hard to connect.” Even if an animal has learned to do something, it doesn’t execute the exact same motor responses every time, says biophysicist Alipasha Vaziri of the Rockefeller University. He adds that common approaches to studying the neural basis of decision-making may not tell the whole story. For instance, monitoring a handful of neurons and then extrapolating from their activity what’s happening brain-wide means that researchers might miss the big picture. Likewise, recording across the whole brain and then averaging results across trials risks losing details essential to understanding how the brain encodes this behavior. © 1986–2020 The Scientist

Keyword: Brain imaging
Link ID: 26990 - Posted: 01.24.2020

Janelia and Google scientists have constructed the most complete map of the fly brain ever created, pinpointing millions of connections between 25,000 neurons. Now, a wiring diagram of the entire brain is within reach. In a darkened room in Ashburn, Virginia, rows of scientists sit at computer screens displaying vivid 3-D shapes. With a click of a mouse, they spin each shape to examine it from all sides. The scientists are working inside a concrete building at the Howard Hughes Medical Institute’s Janelia Research Campus, just off a street called Helix Drive. But their minds are somewhere else entirely – inside the brain of a fly. Each shape on the scientists’ screens represents part of a fruit fly neuron. These researchers and others at Janelia are tackling a goal that once seemed out of reach: outlining each of the fly brain’s roughly 100,000 neurons and pinpointing the millions of places they connect. Such a wiring diagram, or connectome, reveals the complete circuitry of different brain areas and how they're linked. The work could help unlock networks involved in memory formation, for example, or neural pathways that underlie movements. Gerry Rubin, vice president of HHMI and executive director of Janelia, has championed this project for more than a decade. It’s a necessary step in understanding how the brain works, he says. When the project began, Rubin estimated that with available methods, tracing the connections between every fly neuron by hand would take 250 people working for two decades – what he refers to as “a 5,000 person-year problem.”

Keyword: Brain imaging
Link ID: 26984 - Posted: 01.23.2020

Nicola Davis When Mount Vesuvius erupted in AD79, the damage wreaked in nearby towns was catastrophic. Now it appears the heat was so immense it turned one victim’s brain to glass – thought to be the first time this has been seen. Experts say they have discovered that splatters of a shiny, solid black material found inside the skull of a victim at Herculaneum appear to be the remains of human brain tissue transformed by heat. They say the find is remarkable since brain tissue is rarely preserved at all due to decomposition, and where it is found it has typically turned to soap. “To date, vitrified remains of the brain have never been found,” said Dr Pier Paolo Petrone, a forensic anthropologist at the University of Naples Federico II and a co-author of the study. Writing in the New England Journal of Medicine, Petrone and colleagues reveal that the glassy brains belonged to a man of about 25 who was found in the 1960s lying face-down on a wooden bed under a pile of volcanic ash – a pose that suggests he was asleep when disaster struck the town. The bed was in a small room that was part of the Collegium Augustalium, a building relating to an imperial cult that worshipped the former emperor Augustus. The victim, according to Petrone, is believed to have been the caretaker. Petrone said it was when he recently focused his research on human remains found at the college that he noticed the black fragments in the caretaker’s skull. “I noticed something shining inside the head ,” he told the Guardian. “This material was preserved exclusively in the victim’s skull, thus it had to be the vitrified remains of the brain. But it had to be proved beyond any reasonable doubt.” © 2020 Guardian News & Media Limited

Keyword: Brain imaging
Link ID: 26982 - Posted: 01.23.2020

By Kelly Servick The dark, thumping cavern of an MRI scanner can be a lonely place. How can scientists interested in the neural activity underlying social interactions capture an engaged, conversing brain while its owner is so isolated? Two research teams are advancing a curious solution: squeezing two people into one scanner. One such MRI setup is under development with new funding from the U.S. National Science Foundation (NSF), and another has undergone initial testing described in a preprint last month. These designs have yet to prove that their scientific payoff justifies their cost and complexity, plus the requirement that two people endure a constricted almost-hug, in some cases for 1 hour or more. But the two groups hope to open up new ways to study how brains exchange subtle social and emotional cues bound up in facial expressions, eye contact, and physical touch. The tool could “greatly expand the range of investigations possible,” says Winrich Freiwald, a neuroscientist at Rockefeller University. “This is really exciting.” Functional magnetic resonance imaging (fMRI), which measures blood oxygenation to estimate neural activity, is already a common tool for studying social processes. But compared with real social interaction, these experiments are “reduced and artificial,” says Lauri Nummenmaa, a neuroscientist at the University of Turku in Finland. Participants often look at static photos of faces or listen to recordings of speech while lying in a scanner. But photos can’t show the subtle flow of emotions across people’s faces, and recordings don’t allow the give and take of real conversation. © 2019 American Association for the Advancement of Science

Keyword: Brain imaging
Link ID: 26949 - Posted: 01.10.2020

By Rodrigo Pérez Ortega Nearly 2600 years ago, a man was beheaded near modern-day York, U.K.—for what reasons, we still don’t know—and his head was quickly buried in the clay-rich mud. When researchers found his skull in 2008, they were startled to find that his brain tissue, which normally rots rapidly after death, had survived for millennia—even maintaining features such as folds and grooves (above). Now, researchers think they know why. Using several molecular techniques to examine the remaining tissue, the researchers figured out that two structural proteins—which act as the “skeletons” of neurons and astrocytes—were more tightly packed in the ancient brain. In a yearlong experiment, they found that these aggregated proteins were also more stable than those in modern-day brains. In fact, the ancient protein clumps may have helped preserve the structure of the soft tissue for ages, the researchers report today in the Journal of the Royal Society Interface. Aggregated proteins are a hallmark of aging and brain diseases like Alzheimer’s. But the team didn’t find any protein clumps typical of those conditions in the ancient brain. The scientists still aren’t sure what made the proteins aggregate, but they suspect it could have something to do with the burial conditions, which appeared to take place as part of a ritual. In the meantime, the new findings could help researchers gather information from proteins of other ancient tissues from which DNA cannot be easily recovered. © 2019 American Association for the Advancement of Science

Keyword: Brain imaging; Glia
Link ID: 26941 - Posted: 01.09.2020

Nicola Davis and Hannah Devlin Tangles of a protein found inside the brain cells of people with Alzheimer’s disease can be used to predict future brain shrinkage, research suggests. In healthy people, a protein called tau is important in supporting the internal structure of brain cells. However, in those with Alzheimer’s, chemical changes take place that cause the protein to form tangles that disrupt the cells. Such tangles have previously been linked to a loss of brain cells. Now scientists have used imaging techniques to track the extent of tau tangles in the brains of those with early signs of Alzheimer’s, revealing that levels of the protein predict not only how much brain shrinkage will subsequently occur, but where. “Our study supports the notion that tau pathology accumulates upstream of brain tissue loss and clinical symptoms,” said Prof Gil Rabinovici, a co-author of the research from the University of California, San Francisco. A number of drugs targeting tau tangles are currently in clinical trials, including some that aim to interfere with the production of tau in the brain or its spread between cells. Dr Renaud La Joie, another author of the research, said the findings suggested the imaging technique could prove valuable both in choosing which patients to enrol to test such drugs and in monitoring whether the drugs work. Dr Laura Phipps, of Alzheimer’s Research UK, said: “The ability to track tau in the brain will be critical for testing treatments designed to prevent the protein causing damage, and the scans used in this study could be an important tool for future clinical trials.” Writing in the journal Science Translational Medicine, La Joie and colleagues report how they used an imaging technique called PET to study the brains of 32 people aged between 49 and 83 who were in the early stages of showing Alzheimer’s symptoms. © 2020 Guardian News & Media Limited

Keyword: Alzheimers; Brain imaging
Link ID: 26928 - Posted: 01.02.2020

Correspondent Lesley Stahl Who among us hasn't wished we could read someone else's mind, know exactly what they're thinking? Well that's impossible, of course, since our thoughts are, more than anything else, our own. Private, personal, unreachable. Or at least that's what we've always, well, thought. Advances in neuroscience have shown that, on a physical level, our thoughts are actually a vast network of neurons firing all across our brains. So if that brain activity could be identified and analyzed, could our thoughts be decoded? Could our minds be read? Well, a team of scientists at Carnegie Mellon University in Pittsburgh has spent more than a decade trying to do just that. We started our reporting on their work 10 years ago, and what they've discovered since, has drawn us back. In Carnegie Mellon's scanner room, two floors underground, a steady stream of research subjects come to have their brains and thoughts "read" in this MRI machine. It's a type of scanning called functional MRI, FMRI. That looks at what's happening inside the brain as a person thinks. Marcel Just: It's like being an astronomer when the first telescope is discovered, or being a biologist when the first microscope is-- is developed. Neuroscientist Marcel Just says this technology has made it possible for the first time to see the physical makeup of our thoughts. When we first visited Dr. Just's lab ten years ago, he and his team had conducted a study. They put people in the scanner and asked them to think about ten objects, five of them tools like screwdriver and hammer and five of them dwellings like igloo and castle, while measuring activity levels throughout their brains. The idea was to crunch the data and try to identify distinctive patterns of activity for each object. Lesley Stahl: You had them think about a screwdriver. Marcel Just: Uh-huh. Lesley Stahl: And the computer found the place in the brain where that person was thinking "screwdriver?" Marcel Just: Screwdriver isn't one place in the brain. It's many places in the brain. When you think of a screwdriver, you think about how you hold it, how you twist it, what it looks like… Lesley Stahl: And each of those functions are in different places? Marcel Just: Correct. He showed us that by dividing the brain into thousands of tiny cubes and analyzing the amount of activity in each one, his team was able to identify unique patterns for each object. © 2019 CBS Interactive Inc.

Keyword: Emotions; Brain imaging
Link ID: 26853 - Posted: 11.26.2019

Cody A. Siciliano Some individuals consume alcohol their entire adult life without developing an alcohol use disorder. Others, however, quickly transition to compulsive and problematic drinking. Can we determine what makes some people vulnerable to addiction? Alcohol drinking is the third leading cause of preventable death in the United States, and is responsible for millions of deaths per year worldwide. If the reasons why some people are susceptible to alcohol use disorder were known, it might be possible to more effectively treat this devastating disease, or even intervene before serious problems emerge. I have spent my career as a neuroscientist and pharmacologist trying to understand how drugs and alcohol act on the brain, and what makes a brain more or less susceptible to substance use disorders. My laboratory at the Vanderbilt Center for Addiction Research develops approaches for studying addictive behaviors in rats and mice. Using electrochemical and optical approaches to measure brain activity, our goal is to determine how patterns of activity in brain cells give rise to these behaviors – and how we may use this information to treat or prevent substance use disorders. In a report published in the Nov. 22 issue of the journal Science, Kay Tye of the Salk Institute and I set out to understand how binge drinking alters the brain and how this can lead to compulsive behaviors in some drinkers. To study this, we designed an experiment in which mice were scored for their propensity to drink alcohol. We measured compulsive drinking by determining how much they drank when we mixed the alcohol with a bitter tasting substance that mice normally avoid. © 2010–2019, The Conversation US, Inc.

Keyword: Drug Abuse; Brain imaging
Link ID: 26844 - Posted: 11.22.2019

An exciting new study out of the University of Toronto shows that the brain lights up when you think things. “I mean it’s incredible,” said neuroscientist Dr. Prya Laghara. “We now have the technology to put someone into an fMRI, tell them to think things, and then watch their brain light up.” In order to prove this, Dr. Laghara recruited undergraduate students, put them in fMRIs, and then asked them to think things. “I told them to think about anything, anything at all, and no matter what they thought about their brains lit up.” When asked whether her study had any methodological issues, Dr. Laghara scoffed. “We ran this study with 2000 undergraduate participants over the course of three years. In every condition, with every participant, their brain lit up when they thought things.” “My colleagues all over the world are replicating this study, and so far nobody has been able to refute the hypothesis that the brain lights up when you think things. It’s an incredibly robust finding.” Thanks to this breakthrough in neuroscience, the University of Toronto is taking the next decade’s stem cell research funds and using them to purchase ten fMRIs. Copyright Simplosion 2019

Keyword: Brain imaging
Link ID: 26827 - Posted: 11.18.2019

By Michelle Roberts Health editor, BBC News online An infectious disease that can harm the brain and is spread to people by tick bites has been identified in ticks in the UK for the first time. Public Health England (PHE) says it has confirmed cases of tick-borne encephalitis virus in ticks from two parts of England - Thetford Forest and an area on the Hampshire-Dorset border. PHE says the risk to people is still "very low". It is monitoring the situation to check how common the infected ticks may be. What is it? A tick is a tiny, spider-like creature that lives in undergrowth and on animals, including deer and dogs. People who spend time walking in countryside areas where infected ticks can be found are at risk of being bitten and catching diseases they carry. Tick-borne encephalitis virus is already circulating in mainland Europe and Scandinavia, as well as Asia. Evidence now shows it has reached the UK. How it got here is less clear. Experts say infected ticks may have hitched a ride on migratory birds. Earlier this year, a European visitor, who has since recovered, became ill after being bitten by a tick while in the New Forest area, Public Health England says. Further investigations revealed infected ticks were present in two locations in England. Should I worry? Ticks are becoming more common across many parts of the UK, largely due to increasing deer numbers. Being bitten by one doesn't necessarily mean you will get sick. Dr Nick Phin, from Public Health England, said: ''These are early research findings and indicate the need for further work. However, the risk to the general public is currently assessed to be very low." Most people who catch the virus will have no or only mild flu-like symptoms. But the disease can progress to affect the brain and central nervous system and can sometimes be fatal. © 2019 BBC

Keyword: Miscellaneous
Link ID: 26782 - Posted: 11.02.2019

By Laura Sanders Every 20 seconds, a wave of fresh cerebrospinal fluid rolls into the sleeping brain. These slow, rhythmic blasts, described for the first time in the Nov. 1 Science, may help explain why sleep is so important for brain health. Studies on animals have shown that the fluid, called CSF, can wash harmful proteins, including those implicated in Alzheimer’s disease, out of the brain. The new results give heft to the idea that a similar power wash happens in sleeping people. Researchers studied 13 healthy, young people in an MRI scanner as they fell into non-REM sleep, the type of slumber that takes up most of the night. At the same time, the scientists monitored different sorts of activity in participants’ heads. Electrodes measured the activity of large collections of nerve cells, and functional MRI measured the presence of oxygenated blood that gives energy to those nerve cells. By using a form of rapid fMRI, the team also measured another type of activity — the movements of CSF in the brain. Fast fMRI revealed waves of fresh CSF that flowed rhythmically into the sleeping brains, a pattern that was obvious — and big, says study coauthor Laura Lewis, a neuroscientist and engineer at Boston University. “I’ve never had something jump out at me to this degree,” she says. “It was very striking.” Awake people have small, gentle waves of CSF that are largely linked to breathing patterns. In contrast, the sleep waves were tsunamis. “The waves we saw during sleep were much, much larger, and higher velocity,” Lewis says. © Society for Science & the Public 2000–2019

Keyword: Sleep
Link ID: 26781 - Posted: 11.01.2019

By Gina Kolata Thousands of people have received brain scans, as well as cognitive and genetic tests, while participating in research studies. Though the data may be widely distributed among scientists, most participants assume their privacy is protected because researchers remove their names and other identifying information from their records. But could a curious family member identify one of them just from a brain scan? Could a company mining medical records to sell targeted ads do so, or someone who wants to embarrass a study participant? The answer is yes, investigators at the Mayo Clinic reported on Wednesday. A magnetic resonance imaging scan includes the entire head, including the subject’s face. And while the countenance is blurry, imaging technology has advanced to the point that the face can be reconstructed from the scan. Under some circumstances, that face can be matched to an individual with facial recognition software. In a letter published in the New England Journal of Medicine, researchers at the Mayo Clinic showed that the required steps are not complex. But privacy experts questioned whether the process could be replicated on a much larger scale with today’s technology. The subjects were 84 healthy participants in a long-term study of about 2,000 residents of Olmsted County, Minn. Participants get brain scans to look for signs of Alzheimer’s disease, as well as cognitive, blood and genetic tests. © 2019 The New York Times Company

Keyword: Brain imaging
Link ID: 26748 - Posted: 10.24.2019

By Laura Sanders CHICAGO — Light pulses from outside a monkey’s brain can activate nerve cells deep within. This external control, described October 20 at the annual meeting of the Society for Neuroscience, might someday help scientists treat brain diseases such as epilepsy. Controlling nerve cell behavior with light, a method called optogenetics, often requires thin optical fibers to be implanted in the brain (SN: 1/15/10). That invasion can cause infections, inflammation and tissue damage, says study coauthor Diego Mendoza-Halliday of MIT. He and his colleagues created a new light-responsive molecule, called SOUL, that detects extra dim light. After injecting SOUL into macaque monkeys’ brains, researchers shined blue light through a hole in the skull. SOUL-containing nerve cells, which were as deep as 5.8 millimeters in the brain, became active. A dose of orange light stopped this activity. SOUL can’t sense light coming from outside of the macaques’ skulls. But in mice, the system works through the skull, the researchers reported. LEDs implanted just under people’s skulls might one day be used to treat brain diseases. Such a system might be able to temporarily turn off nerve cells that are about to cause an epileptic seizure, for instance. “This is basically scooping out a piece of brain and then putting it back in a few seconds later,” when the risk of a seizure has dropped, Mendoza-Halliday says. © Society for Science & the Public 2000–2019.

Keyword: Brain imaging
Link ID: 26735 - Posted: 10.23.2019

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

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

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

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

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

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