Links for Keyword: Brain imaging

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By Robert Frederick An early sign of neurodegenerative disease at the cellular level is often the loss of integrity in axons, the threadlike part of neurons that conduct impulses. To find out what causes that loss of integrity, researchers have been trying to better understand the axon’s lining, called the membrane-associated periodic scaffold (MPS). If neuroscientists can discover what signals the MPS to disassemble, they may gain an early diagnostic tool for neurodegenerative diseases or a new target for drug therapy. Back in 2013, researchers using advanced optical microscopy identified the presence of rings in the MPS made from the protein actin. At first, the discovery was met with skepticism because no one had seen the rings using electron microscopes, which have more resolution than optical methods. But preparing neurons for electron microscopy often involves dissolving the membrane with a surfactant. “If you remove completely the membrane, you also disorganize the scaffold that is very tightly associated with the membrane,” says Christophe Leterrier, a neuro-biologist at Aix-Marseille Université in France. To see the periodic rings (shown above in orange at increasing levels of zoom) Leterrier combined optical and electron microscopy. Just as previous researchers had done to visualize the MPS, the first step involved a technique called unroofing a cell, which can isolate a cell’s membrane without disorganizing the underlying scaffold. But the researchers then used electron microscopy to image the same unroofed axon: Teamed up with Stéphane Vassilopoulos, Leterrier’s group essentially made a platinum replica of the MPS and used electron microscopy (shown above in grayscale) on the replica “to really see individual proteins.” The researchers published their findings in Nature Communications, discovering that the rings are like braided wreaths made from long actin filaments. Leterrier says the next step is to find what signal will prompt the MPS to disassemble but will not affect a neuron’s other actin structures, such as dendritic spines, which receive other neurons’ signals. © 2020 Sigma Xi, The Scientific Research Honor Society

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27159 - Posted: 04.02.2020

By Stephen Casper. The poet Emily Dickinson rendered the brain wider than the sky, deeper than the sea, and about the weight of God. Scientists facing the daunting task of describing this organ conventionally conjure up different kinds of metaphor — of governance; of maps, infrastructure networks and telecommunications; of machines, robots, computers and the Internet. The comparisons have been practical and abundant. Yet, perhaps because of their ubiquity, the metaphors we use to understand the brain often go unnoticed. We forget that they are descriptors, and see them instead as natural properties. Such hidden dangers are central to biologist and historian Matthew Cobb’s The Idea of the Brain. This ambitious intellectual history follows the changing understanding of the brain from antiquity to the present, mainly in Western thought. Cobb outlines a growing challenge to the usefulness of metaphor in directing and explaining neuroscience research. With refreshing humility, he contends that science is nowhere near working out what brains do and how — or even if anything is like them at all. Cobb shows how ideas about the brain have always been forged from the moral, philosophical and technological frameworks to hand for those crafting the dominant narratives of the time. In the seventeenth century, the French philosopher René Descartes imagined an animal brain acting through hydraulic mechanisms, while maintaining a view of the divine nature of a mind separate from matter. Later authorities, such as the eighteenth-century physician and philosopher Julien Offray de Le Mettrie, secularized the image and compared the human to a machine. The Italian physicist Alessandro Volta rejected the idea of ‘animal electricity’, proposed by his rival Luigi Galvani as a vital force that animates organic matter. Volta was driven at least partly by his aversion to the mechanistic view. © 2020 Springer Nature Limited

Related chapters from BN8e: Chapter 1: Introduction: Scope and Outlook; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27154 - Posted: 03.31.2020

Bob McDonald · CBC Radio Technology used to determine the structure of the Earth's interior using seismic waves has been adapted into a prototype brain scanner that could give results in real time. It could also be cheaper and simpler to use than technologies like MRI or CT scans. For decades, geologists have used sound waves travelling through the Earth, either from earthquakes or artificial sources, to search for oil, image fault lines and attempt to predict earthquakes. Reading reflections and refraction of the waves as they pass through different kinds of rocks and deposits can help geologists essentially do an ultrasound to build up a picture of the Earth. But in recent years seismology has been supercharged by a computational technique called full waveform inversion (FWI), which uses complex computer algorithms to scavenge ever more information from seismic data, and make much more detailed and accurate 3D maps of the Earth's crust. Now scientists at Imperial College London have adapted the same technology into a prototype head-mounted scanner that produced imaging information they say could be used in the future to produce high-resolution 3D images of the brain. The wavefield is shown as it propagates across the head. (Dr Lluís Guasch / Imperial College London / University College London / Nature Digital Medicine) The device uses a helmet fitted with an array of acoustic transducers that act as both sound transmitters and receivers. The system uses low frequency sound waves that are able to penetrate the skull and pass through the brain without harming brain tissue. The sound waves are altered as they pass through different brain structures, then the signals are read and run through the FWI algorithm. In simulations the team got results that make them confident they can produce high-resolution 3D images that may be as good, if not better, than more traditional approaches. ©2020 CBC/Radio-Canada.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27122 - Posted: 03.16.2020

Ashley Yeager Genes that code for the structure and function of brain regions essential for learning, memory, and decision-making are beginning to be revealed, according to a report published last October in Nature Genetics. Analyzing MRI scans and blood samples from more than 38,000 individuals, as well as gene expression, methylation, and neuropathology of hundreds of postmortem brains, an international team of researchers identified 199 genes that affect the development of the brain, the connections and communication among nerve cells, and susceptibility to neurological disorders. New tools for studying neural tissue, such as RNA sequencing, have spurred a “very strong revival in studying human postmortem brains,” says Sabina Berretta, director of the Harvard Brain Tissue Resource Center at McLean Hospital in Boston. The Nature Genetics study and others like it have the potential to answer many questions about how the healthy brain functions, but they highlight one of the major challenges neuroscientists face right now—limited access to donated brain tissue, specifically from individuals unaffected by neurological disorders. While the Nature Genetics study included massive amounts of data from scans and blood, the researchers had gene expression data from only 508 postmortem brains. “We are really fortunate to get donations from people with a very large variety of dementias and other neurological disorders, such as Parkinson’s and Huntington’s disease,” Berretta says. “But we get very few donations from people that suffer from psychiatric disorders, schizophrenia, bipolar disorder, major depression, and anxiety, and [even fewer from] unaffected donors.” As a result, brain banks are reaching out to religious groups and also scientific communities not tied to any particular neurological condition to increase donations of healthy brains. © 1986–2020 The Scientist.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27075 - Posted: 02.27.2020

Diana Kwon In the 16th century, when the study of human anatomy was still in its infancy, curious onlookers would gather in anatomical theaters to catch of a glimpse of public dissections of the dead. In the years since, scientists have carefully mapped the viscera, bones, muscles, nerves, and many other components of our bodies, such that a human corpse no longer holds that same sense of mystery that used to draw crowds. New discoveries in gross anatomy—the study of bodily structures at the macroscopic level—are now rare, and their significance is often overblown, says Paul Neumann, a professor who specializes in the history of medicine and anatomical nomenclature at Dalhousie University. “The important discoveries about anatomy, I think, are now coming from studies of tissues and cells.” Over the last decade, there have been a handful of discoveries that have helped overturn previous assumptions and revealed new insights into our anatomy. “What’s really interesting and exciting about almost all of the new studies is the illustration of the power of new [microscopy and imaging] technologies to give deeper insight,” says Tom Gillingwater, a professor of anatomy at the University of Edinburgh in the UK. “I would guess that many of these discoveries are the start, rather than the end, of a developing view of the human body.” © 1986–2020 The Scientist

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27058 - Posted: 02.20.2020

Blake Richards Despite billions of dollars spent and decades of research, computation in the human brain remains largely a mystery. Meanwhile, we have made great strides in the development of artificial neural networks, which are designed to loosely mimic how brains compute. We have learned a lot about the nature of neural computation from these artificial brains and it’s time to take what we’ve learned and apply it back to the biological ones. Neurological diseases are on the rise worldwide, making a better understanding of computation in the brain a pressing problem. Given the ability of modern artificial neural networks to solve complex problems, a framework for neuroscience guided by machine learning insights may unlock valuable secrets about our own brains and how they can malfunction. Our thoughts and behaviours are generated by computations that take place in our brains. To effectively treat neurological disorders that alter our thoughts and behaviours, like schizophrenia or depression, we likely have to understand how the computations in the brain go wrong. However, understanding neural computation has proven to be an immensely difficult challenge. When neuroscientists record activity in the brain, it is often indecipherable. In a paper published in Nature Neuroscience, my co-authors and I argue that the lessons we have learned from artificial neural networks can guide us down the right path of understanding the brain as a computational system rather than as a collection of indecipherable cells. © 2010–2020, The Conversation US, Inc.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 17: Learning and Memory
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 13: Memory, Learning, and Development
Link ID: 27042 - Posted: 02.14.2020

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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 27040 - Posted: 02.14.2020

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.

Related chapters from BN8e: Chapter 1: Introduction: Scope and Outlook; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 1: An Introduction to Brain and Behavior; Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 27020 - Posted: 02.05.2020

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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 11: Motor Control and Plasticity
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 5: The Sensorimotor System
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.”

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26982 - Posted: 01.23.2020

By Eryn Brown On March 30, 1981, 25-year-old John W. Hinckley Jr. shot President Ronald Reagan and three other people. The following year, he went on trial for his crimes. Defense attorneys argued that Hinckley was insane, and they pointed to a trove of evidence to back their claim. Their client had a history of behavioral problems. He was obsessed with the actress Jodie Foster, and devised a plan to assassinate a president to impress her. He hounded Jimmy Carter. Then he targeted Reagan. In a controversial courtroom twist, Hinckley’s defense team also introduced scientific evidence: a computerized axial tomography (CAT) scan that suggested their client had a “shrunken,” or atrophied, brain. Initially, the judge didn’t want to allow it. The scan didn’t prove that Hinckley had schizophrenia, experts said — but this sort of brain atrophy was more common among schizophrenics than among the general population. It helped convince the jury to find Hinckley not responsible by reason of insanity. Nearly 40 years later, the neuroscience that influenced Hinckley’s trial has advanced by leaps and bounds — particularly because of improvements in magnetic resonance imaging (MRI) and the invention of functional magnetic resonance imaging (fMRI), which lets scientists look at blood flows and oxygenation in the brain without hurting it. Today neuroscientists can see what happens in the brain when a subject recognizes a loved one, experiences failure, or feels pain. Despite this explosion in neuroscience knowledge, and notwithstanding Hinckley’s successful defense, “neurolaw” hasn’t had a tremendous impact on the courts — yet. But it is coming. Attorneys working civil cases introduce brain imaging ever more routinely to argue that a client has or has not been injured. Criminal attorneys, too, sometimes argue that a brain condition mitigates a client’s responsibility. Lawyers and judges are participating in continuing education programs to learn about brain anatomy and what MRIs and EEGs and all those other brain tests actually show.

Related chapters from BN8e: Chapter 15: Emotions, Aggression, and Stress; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 11: Emotions, Aggression, and Stress; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 26960 - Posted: 01.15.2020

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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 19: Language and Lateralization
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 15: Brain Asymmetry, Spatial Cognition, and Language
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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 6: Evolution of the Brain and Behavior
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26941 - Posted: 01.09.2020

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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26827 - Posted: 11.18.2019

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

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
Link ID: 26748 - Posted: 10.24.2019

Alexander D. Reyes Information in the brain is thought to be encoded as complex patterns of electrical impulses generated by thousands of neuronal cells. Each impulse, known as an action potential, is mediated by currents of charged ions flowing through a neuron’s membrane. But how the ions pass through the insulated membrane of the neuron remained a puzzle for many years. In 1976, Erwin Neher and Bert Sakmann developed the patch-clamp technique, which showed definitively that currents result from the opening of many channel proteins in the membrane1. Although the technique was originally designed to record tiny currents, it has since become one of the most important tools in neuroscience for studying electrical signals — from those at the molecular scale to the level of networks of neurons. By the 1970s, current flowing through the cell was generally accepted to result from the opening of many channels in the membrane, although the underlying mechanism was unknown. At that time, current was commonly recorded by impaling tissue with a sharp electrode — a pipette with a very fine point. Unfortunately, however, the signal recorded in this way was excessively noisy, and so only the large, ‘macroscopic’ current — the collective current mediated by many different types of channel — that flows through the tissue could be resolved. In 1972, Bernard Katz and Ricardo Miledi2, pioneers of the biology of the synaptic connections between cells, managed to infer from the macroscopic current certain properties of the membrane channels, but only after a heroic effort to exclude all possible confounding factors. The problem was that the macroscopic current could be influenced by factors not directly related to channel activity, such as cell geometry and modulatory processes that regulate cell excitability. Also troublesome was that interpretations of macroscopic-current features were based on unverified assumptions about the statistics of individual channel activity2,3. Despite Katz and Miledi’s careful analyses, there was a lingering doubt about whether their conclusions were correct. The crucial data were obtained by Neher and Sakmann using patch clamp. © 2019 Springer Nature Limited

Related chapters from BN8e: Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 26737 - Posted: 10.23.2019

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.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
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.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System
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.

Related chapters from BN8e: Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Related chapters from MM:Chapter 2: Cells and Structures: The Anatomy of the Nervous System; Chapter 3: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 26708 - Posted: 10.16.2019