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

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By Sundas Hashmi It was the afternoon of Jan. 31. I was preparing for a dinner party and adding final touches to my cheese platter when everything suddenly went dark. I woke up feeling baffled in a hospital bed. My husband filled me in: Apparently, I had suffered a massive seizure a few hours before our guests were to arrive at our Manhattan apartment. Our children’s nanny found me and I was rushed to the hospital. That had been three days earlier. My husband and I were both mystified: I was 37 years old and had always been in excellent health. In due course, a surgeon dropped by and told me I had a glioma, a type of brain tumor. It was relatively huge but operable. I felt sick to my stomach. Two weeks later, I was getting wheeled to the operating theater. I wouldn’t know the pathology until much later. I said my goodbyes to everyone — most importantly to my children, Sofia, 6, and Nyle, 2 — and prepared to die. But right before the surgery, in a very drugged state, I asked the surgeon to please get photos of me and my brother from my husband. I wanted the surgeon to see them. My brother had died two decades earlier from a different kind of brain tumor — a glioblastoma. I was 15 at the time, and he was 18. He died within two years of being diagnosed. Those two years were the worst period of my life. Doctors in my home country of Pakistan refused to take him, saying his case was fatal. So, my parents gathered their savings and flew him to Britain, where he was able to get a biopsy (his tumor was in an inoperable location) and radiation. Afterward, we had to ask people for donations so he could get the gamma knife treatment in Singapore that my parents felt confident would save him. In the end, nothing worked, and he died, taking 18 years of memories with him. © 2020 The New York Times Company

Keyword: Glia
Link ID: 27536 - Posted: 10.21.2020

Keith A. Trujillo1, Alfredo Quiñones-Hinojosa2, Kenira J. Thompson3 Joe Louis Martinez Jr. died on 29 August at the age of 76. In addition to making extraordinary contributions to the fields of neurobiology and Chicano psychology, Joe was a tireless advocate of diversity, equity, and inclusion in the sciences. He established professional development programs for individuals from underrepresented groups and provided lifelong mentoring as they pursued careers in science and academia. Joe was passionately devoted to expanding opportunities in the sciences well before diversity became a visible goal for scientific organizations and academic institutions. Born in Albuquerque, New Mexico, on 1 August 1944, Joe received his bachelor's degree in psychology from the University of San Diego in 1966; his master's in experimental psychology from New Mexico Highlands University in 1968; and his Ph.D. in physiological psychology from the University of Delaware in 1971. His faculty career began in 1972 at California State University, San Bernardino (CSUSB), shortly after the campus was established. He later completed postdocs in the laboratory of neurobiologist James McGaugh at the University of California, Irvine, and with neurobiologist Floyd Bloom at the Salk Institute for Biological Studies in San Diego, California. The University of California, Berkeley, recruited Joe in 1982, and he served as a professor as well as the area head of biopsychology and faculty assistant to the vice chancellor for affirmative action. As the highest-ranking Hispanic faculty member in the University of California system, Joe used his voice to help others from underrepresented groups. However, he felt that he could have a greater impact on diversity in the sciences by helping to build a university with a high concentration of Hispanic students, so in 1995 he moved to the University of Texas, San Antonio (UTSA). He began as a professor of biology and went on to assume a range of leadership roles, including director of the Cajal Neuroscience Institute. At UTSA, he worked with colleagues to obtain nearly $18 million in funding for neuroscience research and education. In 2012, he moved to the University of Illinois at Chicago where he served as professor and psychology department head until his retirement in 2016. At each institution, he embraced the opportunity to provide guidance and mentoring to innumerable students, faculty, and staff. © 2020 American Association for the Advancement of Science.

Keyword: Learning & Memory
Link ID: 27523 - Posted: 10.16.2020

By James Gorman Montessa, a 46-year-old chimpanzee, has been through a lot. The first record of her life is the note that she was purchased from an importer in 1975 for the research colony in New Mexico at the Holloman Air Force Base, when she was about a year old. She’s still there. It’s now called the Alamogordo Primate Facility, and Montessa, who was probably born in the wild and captured for sale, is just one of 39 chimpanzees living in limbo there, all of them the property of the National Institutes of Health. Over the past 45 years, Montessa has been pregnant five times and given birth four times. Publicly available records don’t show much about what kind of experiments were performed on her, but she was involved in a hormone study one year, and in two other years underwent a number of liver biopsies. When Dr. Francis Collins, the director of the N.I.H., decided in 2015 that all federally owned chimps would be permanently retired from research, it seemed that Montessa might get a chance to wander around on the grass at Chimp Haven in Louisiana, the designated and substantially N.I.H.-supported sanctuary. No such luck. The retirement plan had one caveat: Any chimpanzees considered too frail to be moved because of age, illness or both would stay at Alamogordo. They would no longer be subject to experiments, they were supposed to be housed in groups of seven or more, and they would have access to outdoor space and behavioral stimulation (toys, for example). But a year ago, the N.I.H. decided that Montessa and 38 other chimpanzees could not move to Chimp Haven, relying on Alamogordo staff recommendations that the chimps, many with diabetes or heart disease, would suffer and might even die if they were transferred to the sanctuary. © 2020 The New York Times Company

Keyword: Animal Rights
Link ID: 27507 - Posted: 10.07.2020

Paulina Villegas Texas Gov. Greg Abbott issued a disaster declaration in Brazoria County on Sunday after the discovery in the local water supply system of an amoeba that can cause a rare and deadly infection of the brain. “The state of Texas is taking swift action to respond to the situation and support the communities whose water systems have been impacted by this ameba,” Abbott (R) in a news release Sunday. “I urge Texans in Lake Jackson to follow the guidance of local officials and take the appropriate precautions to protect their health and safety as we work to restore safe tap water in the community.” The governor’s declaration follows an investigation of the death of 6-year-old Josiah McIntyre in Lake Jackson this month after he contracted the brain-eating microbe, which prompted local authorities and experts from the Centers for Disease Control and Prevention to test the water. The preliminary results came back Friday, showing that three out of 11 samples collected tested positive. One of the samples came from a hose bib at the boy’s home, Lake Jackson City Manager Modesto Mundo said, according to CBS News. The others came from a “splash pad” play fountain and a hydrant. “The notification to us at that time was that he had played at one of [the] play fountains and he may have also played with a water hose at the home,” Mundo said. On Friday night, the Brazosport Water Authority issued a do-not-use advisory for eight communities after confirmation of the presence of Naegleria fowleri, which destroys brain tissue, then causes swelling of the brain, known as amebic meningoencephalitis. It urged residents to not use the tap water for drinking and cooking. © 1996-2020 The Washington Post

Keyword: Miscellaneous
Link ID: 27499 - Posted: 09.30.2020

Jon Hamilton Mental illness can run in families. And Dr. Kafui Dzirasa grew up in one of these families. His close relatives include people with schizophrenia, bipolar disorder and depression. As a medical student, he learned about the ones who'd been committed to psychiatric hospitals or who "went missing" and were discovered in alleyways. Dzirasa decided to dedicate his career to "figuring out how to make science relevant to ultimately help my own family." He became a psychiatrist and researcher at Duke University and began to study the links between genes and brain disorders. Then Dzirasa realized something: "I was studying genes that were specifically related to illness in folks of European ancestry." His family had migrated from West Africa, which meant anything he discovered might not apply to them. Dzirasa also realized that people with his ancestry were missing not only from genetics research but from the entire field of brain science. "It was a really crushing moment for me," he says. So when a group in Baltimore asked Dzirasa to help do something about the problem, he said yes. The group is the African Ancestry Neuroscience Research Initiative. It's a partnership between community leaders and the Lieber Institute for Brain Development, an independent, nonprofit research organization on the medical campus of Johns Hopkins University. © 2020 npr

Keyword: Attention
Link ID: 27491 - Posted: 09.28.2020

For Armin Raznahan, publishing research on sex differences is a fraught proposition. Now chief of the section on developmental neurogenomics at the National Institutes of Health, Raznahan learned early that searching for dissimilarities between men’s and women’s brains can have unintended effects. “I got my fingers burned when I first started,” Raznahan says. As a PhD student, he published a study that examined structural differences between men’s and women’s brains and how they changed with age. “We observed a particular pattern, and we were very cautious about just describing it, as one should be, not jumping to functional interpretations,” he says. Despite his efforts, The Wall Street Journal soon published an article that cited his study in a defense of single-sex schooling, under the assumption that boys and girls must learn in distinct ways because their brain anatomy is slightly different. “That really threw me,” he says. “The experience has stayed with me.” Nevertheless, Raznahan has continued to study sex differences, in the hope that they could help us better understand neurodevelopmental disorders. He focuses on people with sex chromosome aneuploidy, or any variation other than XX (typically female) and XY (typically male). People with genetic variations (such as XXY) have an inflated risk of autism spectrum disorder, ADHD, and anxiety, among other ailments. Raznahan’s hope is that uncovering if and how men’s and women’s brains differ—for example, in the sizes of regions or the strengths of the connections among them—could help us figure out why people with aneuploidy are more likely to experience neurodevelopmental and psychiatric concerns. Solving this puzzle could be a step toward unlocking the perplexing mystery of psychiatric illness. © 2020 Condé Nast

Keyword: Sexual Behavior; Brain imaging
Link ID: 27451 - Posted: 09.05.2020

By Moises Velasquez-Manoff Jack Gallant never set out to create a mind-reading machine. His focus was more prosaic. A computational neuroscientist at the University of California, Berkeley, Dr. Gallant worked for years to improve our understanding of how brains encode information — what regions become active, for example, when a person sees a plane or an apple or a dog — and how that activity represents the object being viewed. By the late 2000s, scientists could determine what kind of thing a person might be looking at from the way the brain lit up — a human face, say, or a cat. But Dr. Gallant and his colleagues went further. They figured out how to use machine learning to decipher not just the class of thing, but which exact image a subject was viewing. (Which photo of a cat, out of three options, for instance.) One day, Dr. Gallant and his postdocs got to talking. In the same way that you can turn a speaker into a microphone by hooking it up backward, they wondered if they could reverse engineer the algorithm they’d developed so they could visualize, solely from brain activity, what a person was seeing. The first phase of the project was to train the AI. For hours, Dr. Gallant and his colleagues showed volunteers in fMRI machines movie clips. By matching patterns of brain activation prompted by the moving images, the AI built a model of how the volunteers’ visual cortex, which parses information from the eyes, worked. Then came the next phase: translation. As they showed the volunteers movie clips, they asked the model what, given everything it now knew about their brains, it thought they might be looking at. The experiment focused just on a subsection of the visual cortex. It didn’t capture what was happening elsewhere in the brain — how a person might feel about what she was seeing, for example, or what she might be fantasizing about as she watched. The endeavor was, in Dr. Gallant’s words, a primitive proof of concept. And yet the results, published in 2011, are remarkable. The reconstructed images move with a dreamlike fluidity. In their imperfection, they evoke expressionist art. (And a few reconstructed images seem downright wrong.) But where they succeed, they represent an astonishing achievement: a machine translating patterns of brain activity into a moving image understandable by other people — a machine that can read the brain. © 2020 The New York Times Company

Keyword: Vision; Brain imaging
Link ID: 27448 - Posted: 09.02.2020

When it comes to brain cells, one size does not fit all. Neurons come in a wide variety of shapes, sizes, and contain different types of brain chemicals. But how did they get that way? A new study in Nature suggests that the identities of all the neurons in a worm are linked to unique members of a single gene family that control the process of converting DNA instructions into proteins, known as gene expression. The results of this study could provide a foundation for understanding how nervous systems have evolved in many other animals, including humans. The study was funded by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health. “The central nervous systems of all animals, from worms to humans, are incredibly intricate and highly ordered. The generation and diversity of a plethora of neuronal cell types is driven by gene expression,” said Robert Riddle, Ph.D., program director at NINDS. “So, it is surprising and exciting to consider that the cell diversity we see in the entire nervous system could come from a just a single group of genes.” Researchers led by Oliver Hobert, Ph.D., professor of biochemistry and molecular biophysics at Columbia University in New York City and graduate student Molly B. Reilly, wanted to know how brain cells in the C. elegans worm got their various shapes and functions. For these experiments, the researchers used a genetically engineered worm in which individual neurons were color coded. In addition, coding sequences for green fluorescence protein were inserted into homeobox genes, a highly conserved set of genes known to play fundamental roles in development. Homeobox gene expression patterns were determined by examining the patterns of the glowing fluorescent marker.

Keyword: Development of the Brain; Brain imaging
Link ID: 27428 - Posted: 08.20.2020

By Abdul-Kareem Ahmed “He doesn’t look like himself,” his wife said. It was midnight, and I was consulting on a patient in the emergency room. He was 48 years old and complaining of a headache. Ten years ago my attending had partially removed a benign tumor growing in his cerebellum, part of the hindbrain that controls movement, coordination and speech. Our team had also placed a shunt in his brain. The brain is buoyed and bathed by cerebrospinal fluid. This clear fluid is made in large cavities, called ventricles, and is eventually absorbed by veins. The tumor’s inoperable remnant had blocked the fluid’s natural escape, causing it to build up, a condition known as hydrocephalus. A shunt is a thin rubber tube that is placed in the ventricles of the brain and tunneled under the skin, into the abdomen. It can have a programmable pressure valve, a gauge that sits under the scalp. His shunt had been siphoning excess fluid to his abdomen for years where it was absorbed, preventing life-threatening high pressure in the brain. Today, however, something was wrong, and I thought it was revealed on his new head CT. His ventricles were very large, suggesting high pressure. “I get a bad headache when I sit up,” he mumbled. “Sometimes I vomit. I feel better when I lie flat.” His wife, a strong and kindhearted woman, corroborated his complaint. “He’s also having memory problems, and he’s losing his balance when he walks,” she added. His symptoms were the opposite of what I expected. He was describing a low-pressure headache. He was relieved by lying down but worsened when sitting up.

Keyword: Pain & Touch
Link ID: 27397 - Posted: 08.03.2020

"Julich-Brain" is the name of the first 3D-atlas of the human brain that reflects the variability of the brain’s structure with microscopic resolution. The atlas features close to 250 structurally distinct areas, each one based on the analysis of 10 brains. More than 24000 extremely thin brain sections were digitized, assembled in 3D and mapped by experts. As part of the new EBRAINS infrastructure of the European Human Brain Project, the atlas serves as an interface to link different information about the brain in a spatially precise way. German researchers led by Prof. Katrin Amunts have now presented the new brain atlas in the renowned journal Science. Under the microscope, it can be seen that the human brain is not uniformly structured, but divided into clearly distinguishable areas. They differ in the distribution and density of nerve cells and in function. With the Julich-Brain, researchers led by Katrin Amunts now present the most comprehensive digital map of the cellular architecture and make it available worldwide via the EBRAINS research infrastructure. "On the one hand, the digital brain atlas will help to interpret the results of neuroimaging studies, for example of patients, more accurately", says Katrin Amunts, Director at the German Research Center Juelich and Professor at the University of Düsseldorf. "On the other hand, it is becoming the basis for a kind of 'Google Earth' of the brain - because the cellular level is the best interface for linking data about very different facets of the brain. ©2017 Human Brain Project.

Keyword: Brain imaging
Link ID: 27396 - Posted: 08.03.2020

By Karen Kwon, Liz Tormes In 1968 an exhibit entitled Cybernetic Serendipity: The Computer and the Arts was held at the Institute of Contemporary Arts in London. The first major event of its kind, Cybernetic Serendipity’s aim was to “present an area of activity which manifests artists’ involvement with science, and the scientists’ involvement with the arts,” wrote British art critic Jasia Reichardt, who curated the exhibit. Even though it was an art show, “most of the participants in the exhibition were scientists,” Reichardt said in a 2014 video. “Artists didn’t have computers in the 1960s.” A lot has changed since then, however. Computers, no longer the commodity of a select few, help artists to deviate from more traditional mediums. The changes since the 1960s are well-reflected in the entries for the 2020 Art of Neuroscience competition, held by the Netherlands Institute for Neuroscience. Now marking its 10th year, the contest features some highly technological pieces and others grounded in classical methods, such as drawing with pen on paper. The winning entries were created by independent artists, as well as working scientists, demonstrating that art and neuroscience can inspire both professions. A winner and four honorable mentions were selected from dozens of submitted works. And seven pieces were chosen by Scientific American as Editors’ Picks. (Photography editor Liz Tormes served on the panel of judges for the competition.) © 2020 Scientific American

Keyword: Brain imaging
Link ID: 27381 - Posted: 07.25.2020

Salvatore Domenic Morgera How the brain works remains a puzzle with only a few pieces in place. Of these, one big piece is actually a conjecture: that there’s a relationship between the physical structure of the brain and its functionality. The brain’s jobs include interpreting touch, visual and sound inputs, as well as speech, reasoning, emotions, learning, fine control of movement and many others. Neuroscientists presume that it’s the brain’s anatomy – with its hundreds of billions of nerve fibers – that make all of these functions possible. The brain’s “living wires” are connected in elaborate neurological networks that give rise to human beings’ amazing abilities. It would seem that if scientists can map the nerve fibers and their connections and record the timing of the impulses that flow through them for a higher function such as vision, they should be able to solve the question of how one sees, for instance. Researchers are getting better at mapping the brain using tractography – a technique that visually represents nerve fiber routes using 3D modeling. And they’re getting better at recording how information moves through the brain by using enhanced functional magnetic resonance imaging to measure blood flow. But in spite of these tools, no one seems much closer to figuring out how we really see. Neuroscience has only a rudimentary understanding of how it all fits together. To address this shortcoming, my team’s bioengineering research focuses on relationships between brain structure and function. The overall goal is to scientifically explain all the connections – both anatomical and wireless – that activate different brain regions during cognitive tasks. We’re working on complex models that better capture what scientists know of brain function. t © 2010–2020, The Conversation US, Inc.

Keyword: Brain imaging
Link ID: 27373 - Posted: 07.18.2020

By Arianne Cohen1 minute Read You know all those studies about brain activity? The ones that reveal thought patterns and feelings as a person performs a task? There’s a problem: The measurement they’re based on is inaccurate, according to a study out of Duke University that is rocking the field. Functional MRI machines (fMRIs) are excellent at determining the brain structures involved in a task. For example, a study asking 50 people to count or remember names while undergoing an fMRI scan would accurately identify which parts of the brain are active during the task. Brain scans showing functional MRI mapping for three tasks across two different days. Warm colors show the high consistency of activation levels across a group of people. Cool colors represent how poorly unique patterns of activity can be reliably measured in individuals. View image larger here. [Image: Annchen Knodt/Duke University] The trouble is that when the same person is asked to do the same tasks weeks or months apart, the results vary wildly. This is likely because fMRIs don’t actually measure brain activity directly: They measure blood flow to regions of the brain, which is used as a proxy for brain activity because neurons in those regions are presumably more active. Blood flow levels, apparently, change. “The correlation between one scan and a second is not even fair, it’s poor,” says lead author Ahmad Hariri, a professor of neuroscience and psychology at Duke University. The researchers reexamined 56 peer-reviewed, published papers that conducted 90 fMRI experiments, some by leaders in the field, and also looked at the results of so-called “test/retest” fMRIs, where 65 subjects were asked to do the same tasks months apart. They found that of seven measures of brain function, none had consistent readings.

Keyword: Brain imaging
Link ID: 27339 - Posted: 07.01.2020

The Human Brain Project (HBP) has announced the start of its final phase as an EU-funded FET Flagship. The European Commission has signed a grant agreement to fund the HBP with 150 million Euros from now until 2023. Over the next three years, the project will narrow its focus to advance three core scientific areas – brain networks, their role in consciousness, and artificial neural nets – while expanding its innovative EBRAINS infrastructure. EBRAINS offers the most comprehensive atlas and database on the human brain, directly coupled with powerful computing and simulation tools, to research communities around neuroscience, medicine and technology. Currently transitioning into a sustainable infrastructure, EBRAINS will remain available to the scientific community, as a lasting contribution of the HBP to global scientific progress. Supercomputers, Big Data Analytics, Simulation, Robots and AI have all become new additions to the “toolbox” of modern neuroscience – a development strongly pushed forward by the HBP and its EBRAINS infrastructure. Started in 2013 as a FET Flagship project, the HBP is the largest brain science project in Europe. Now entering the final phase of its ten-year lifespan, the project is proud to present its scientific workplan and transformative technological offerings for brain research and brain-inspired research and development. HBP’s scientific activities in the new phase focus on three topics: networks that are studied across different spatial and temporal scales, their significance for consciousness and disorders of consciousness, and the development of artificial neural networks and neurorobotics.

Keyword: Brain imaging
Link ID: 27337 - Posted: 07.01.2020

Ruth Williams Turning off just one factor in the brain’s astrocyte cells is sufficient to convert them into neurons in live mice, according to a paper published in Nature today (June 24) and one this spring by another research team in Cell. By flipping this cellular identity switch, researchers have, to some extent, been able to reverse the neuron loss and motor deficits caused by a Parkinson’s-like illness. Not everyone is entirely convinced by the claims. “I think this is very exciting work,” says Pennsylvania State University’s Gong Chen of the Nature paper. It reaffirms that “using the brain’s internal glial cells to regenerate new neurons is a really new avenue for the treatment of brain disorders,” he continues. Chen, who is also based at Jinan University and is the chief scientific officer for NeuExcell—a company developing astrocyte-to-neuron conversion therapies—has performed such conversions in the living mouse brain by a different method but was not involved in the new study. In Parkinson’s disease, dopaminergic neurons within the brain’s substantia nigra—a region in the midbrain involved in movement and reward—gradually die. This results in a deterioration of motor control, characterized by tremors and other types of dyskinesia, with other faculties such as cognition and mood sometimes affected too, especially at later stages of the disease. While treatments to boost diminishing dopamine levels, such as the drug levodopa, can ameliorate symptoms, none can stop the underlying disease process that relentlessly eats away at the patient’s neurological functions and quality of life. © 1986–2020 The Scientist.

Keyword: Parkinsons; Glia
Link ID: 27324 - Posted: 06.26.2020

Published by Steven Novella under Neuroscience This is an important and sobering study, that I fear will not get a lot of press attention – especially in the context of current events. It is a bit wonky, but this is exactly the level of knowledge one needs in order to be able to have any chance of consuming and putting into context scientific research. I have discussed fMRI previously – it stands for functional magnetic resonance imaging. It uses MRI technology to image blood flow to different parts of the brain, and from that infer brain activity. It is used more in research than clinically, but it does have some clinical application – if, for example, we want to see how active a lesion in the brain is. In research it is used to help map the brain, to image how different parts of the brain network and function together. It is also used to see which part of the brain lights up when subjects engage in specific tasks. It is this last application of fMRI that was studied. Professor Ahmad Hariri from Duke University just published a reanalysis of the last 15 years of his own research, calling into question its validity. Any time someone points out that an entire field of research might have some fatal problems, it is reason for concern. But I do have to point out the obvious silver lining here – this is the power of science, self-correction. This is a dramatic example, with a researcher questioning his own research, and not afraid to publish a study which might wipe out the last 15 years of his own research. Copyright © 2020 All Rights Reserved .

Keyword: Brain imaging
Link ID: 27288 - Posted: 06.08.2020

By David Templeton For much of the 20th century, most people thought that stress caused stomach ulcers. But that belief was largely dismissed 38 years ago when a study, which led to a Nobel Prize in 2016, described the bacterium that generates inflammation in the gastrointestinal tract and causes peptic ulcers and gastritis. “The history of the idea that stress causes ulcers took a side step with the discovery of Helicobacter pylori,” said Dr. David Levinthal, director of the University of Pittsburgh Neurogastroenterology & Motility Center. “For the longest time — most of the 20th century — the dominant idea was that stress was the cause of ulcers until the early 1980s with discovery of Helicobacter pylori that was tightly linked to the risk of ulcers. That discovery was critical but maybe over-generalized as the only cause of ulcers.” Now in an important world first, a study co-authored by Levinthal and Peter Strick, both from the Pitt School of Medicine, has explained what parts of the brain’s cerebral cortex influence stomach function and how it can affect health. “Our study shows that the activity of neurons in the cerebral cortex, the site of conscious mental function, can impact the ability of bacteria to colonize the stomach and make the person more sensitive to it or more likely to harbor the bacteria,” Levinthal said. The study goes far beyond ulcers by also providing evidence against the longstanding belief that the brain’s influence on the stomach was more reflexive and with limited, if any, involvement of the thinking brain. And for the first time, the study also provides a general blueprint of neural wiring that controls the gastrointestinal tract. © 2020 StarTribune.

Keyword: Obesity
Link ID: 27286 - Posted: 06.06.2020

Hundreds of published studies over the last decade have claimed it's possible to predict an individual’s patterns of thoughts and feelings by scanning their brain in an MRI machine as they perform some mental tasks. But a new analysis by some of the researchers who have done the most work in this area finds that those measurements are highly suspect when it comes to drawing conclusions about any individual person’s brain. Watching the brain through a functional MRI machine (fMRI) is still great for finding the general brain structures involved in a given task across a group of people, said Ahmad Hariri, a professor of psychology and neuroscience at Duke University who led the reanalysis. “Scanning 50 people is going to accurately reveal what parts of the brain, on average, are more active during a mental task, like counting or remembering names,” Hariri said Functional MRI measures blood flow as a proxy for brain activity. It shows where blood is being sent in the brain, presumably because neurons in that area are more active during a mental task. The problem is that the level of activity for any given person probably won’t be the same twice, and a measure that changes every time it is collected cannot be applied to predict anyone’s future mental health or behavior. Hariri and his colleagues reexamined 56 published papers based on fMRI data to gauge their reliability across 90 experiments. Hariri said the researchers recognized that “the correlation between one scan and a second is not even fair, it’s poor.” © Copyright 2020 Duke University.

Keyword: Brain imaging
Link ID: 27283 - Posted: 06.04.2020

by Chloe Williams / A new flexible electrode array can detect the activity of neurons in a rat’s brain at high resolution for more than a year1. The device could be used to study how neuronal activity is altered in autism. Arrays usually have wires connected to each electrode to pick up its signal, but this design is bulky and works only in arrays consisting of 100 electrodes or fewer, limiting the array’s coverage and resolution. Devices with thousands of electrodes have integrated switches to consolidate signals into fewer wires. But these devices usually have a lifespan of only a few days. Their polymer-based coatings are often permeable to water or contain tiny defects that allow body fluids to seep into the device and current to leak out, damaging both the device and brain tissue. The new device combines electronic switches and a specialized protective coating so that scientists can record activity at the surface of the brain at high resolution over extended periods of time. The array, called Neural Matrix, consists of 1,008 surface electrodes laid out in 28 columns and 36 rows. Switches, or transistors, built into the array combine signals from all the electrodes in a column to a single output wire. The signals from each electrode in the column are recorded via the wire in a specific sequence, making it possible to separate them later. © 2020 Simons Foundation

Keyword: Brain imaging
Link ID: 27282 - Posted: 06.04.2020

by Emily Anthes The overproduction of proteins in brain cells called microglia causes social impairments, cognitive deficits and repetitive behavior in male mice, a new study has found.1 These behavioral differences are not present in female mice, or in mice that produce excess protein in other brain cells, including neurons or star-shaped support cells known as astrocytes. Microglia help eliminate excess synapses — connections between brain cells — that form early in life; this pruning process is crucial to healthy brain development. But male mice that have been engineered to overproduce proteins in these cells have enlarged microglia. That, in turn, lowers the cells’ mobility and may prevent them from migrating to synapses that need eliminating. In support of that idea, the mice have too many synapses, the researchers found — a result that mirrors evidence that certain brain regions may be overconnected in people with autism. “Increased protein synthesis in microglia is sufficient to cause autism phenotypes in mice,” says lead investigator Baoji Xu, professor of neuroscience at the Scripps Research Institute in Jupiter, Florida. “Problems in microglia could be an important pathological mechanism for autism.” Malfunctioning microglia: The researchers studied mice that produce excess levels of EIF4E, a protein that facilitates the synthesis of other proteins. Mutations in several genes linked to autism — including TSC1, TSC2, PTEN and FMR1 — are associated with elevated levels of an active form of EIF4E and, as a result, many other proteins in the brain. Mice that overproduce EIF4E also display autism-like behavior, researchers have previously found. © 2020 Simons Foundation

Keyword: Autism; Glia
Link ID: 27273 - Posted: 06.01.2020