Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior

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Sara Reardon A medical imaging device that can create 3D renderings of the entire human body in as little as 20 seconds could soon be used for a wide variety of research and clinical applications. The modified positron emission tomography (PET) scanner is faster than conventional PET scans — which can take an average of 20 minutes — and requires less radiation exposure for the person being imaged. Researchers presented video taken by the device last week at the US National Institutes of Health’s High-Risk, High-Reward Research Symposium in Bethesda, Maryland. The machine could be especially helpful for imaging children, who tend to wiggle around inside a scanner and ruin the measurements, as well as for studies of how drugs move through the body, says Sanjay Jain, a paediatrician and infectious-disease physician at Johns Hopkins University in Baltimore, Maryland. Standard PET scanners detect γ-rays from radioactive tracers that doctors inject into the person being imaged. The person’s cells take up the molecule and break it down, releasing two γ-rays. A ring-shaped detector positioned around the person measures the angle and speed of the rays and reconstructs their origin, creating a 3D map of the cells that are metabolizing the molecule. The ring is just 25 centimetres thick, however, so physicians can image only a small portion of the body at a time. Capturing larger areas requires them to dose the person with more of the radioactive molecule ― it decays quickly, which means the signal fades fast ― and move them back and forth through the ring. © 2019 Springer Nature Publishing AG

Keyword: Brain imaging
Link ID: 26328 - Posted: 06.14.2019

By Lindsey Bever Doctors had broken the disheartening news to Rachel Palma, explaining that the lesion on her brain was suspected to be a tumor, and her scans suggested that it was cancerous. Palma, a newlywed entering a new chapter in her life, said she was in shock, unwilling to believe it was true. In September, scrubbed-up surgeons in an operating room at Mount Sinai Hospital in New York City opened Palma’s cranium and steeled themselves for a malignant brain tumor, said Jonathan Rasouli, chief neurosurgery resident at the Icahn School of Medicine at Mount Sinai. But instead, Rasouli said, they saw an encapsulated mass resembling a quail egg. “We were all saying, ‘What is this?’ ” Rasouli recalled Thursday in a phone interview with The Washington Post. “It was very shocking. We were scratching our heads, surprised at what it looked like.” The surgeons removed it from Palma’s brain and placed it under a microscope to get a closer look. Then they sliced into it — and found a baby tapeworm. Palma, from Middletown, N.Y., said she had mixed emotions about it. “Of course I was grossed out,” the 42-year-old said Thursday, explaining that no one wants to think there’s a tapeworm growing inside an egg in his or her brain. “But of course, I was also relieved. It meant that no further treatment was necessary.” A scan showing the tapeworm in Rachel Palma's brain. (Mount Sinai Health System) © 1996-2019 The Washington Post

Keyword: Miscellaneous
Link ID: 26308 - Posted: 06.07.2019

Sandeep Ravindran In 2012, computer scientist Dharmendra Modha used a powerful supercomputer to simulate the activity of more than 500 billion neurons—more, even, than the 85 billion or so neurons in the human brain. It was the culmination of almost a decade of work, as Modha progressed from simulating the brains of rodents and cats to something on the scale of humans. The simulation consumed enormous computational resources—1.5 million processors and 1.5 petabytes (1.5 million gigabytes) of memory—and was still agonizingly slow, 1,500 times slower than the brain computes. Modha estimates that to run it in biological real time would have required 12 gigawatts of energy, about six times the maximum output capacity of the Hoover Dam. “And yet, it was just a cartoon of what the brain does,” says Modha, chief scientist for brain-inspired computing at IBM Almaden Research Center in northern California. The simulation came nowhere close to replicating the functionality of the human brain, which uses about the same amount of power as a 20-watt lightbulb. Since the early 2000s, improved hardware and advances in experimental and theoretical neuroscience have enabled researchers to create ever larger and more-detailed models of the brain. But the more complex these simulations get, the more they run into the limitations of conventional computer hardware, as illustrated by Modha’s power-hungry model. © 1986–2019 The Scientist

Keyword: Robotics
Link ID: 26269 - Posted: 05.28.2019

By Kenneth Miller A model of Ben Barres’ brain sits on the windowsill behind his desk at Stanford University School of Medicine. To a casual observer, there’s nothing remarkable about the plastic lump, 3-D-printed from an MRI scan. Almost lost in the jumble of papers, coffee mugs, plaques and trophies that fill the neurobiologist’s office, it offers no hint about what Barres’ actual gray matter has helped to accomplish: a transformation of our understanding of brains in general, and how they can go wrong. Barres is a pioneer in the study of glia. This class of cells makes up 90 percent of the human brain, but gets far less attention than neurons, the nerve cells that transmit our thoughts and sensations at lightning speed. Glia were long regarded mainly as a maintenance crew, performing such unglamorous tasks as ferrying nutrients and mopping up waste, and occasionally mounting a defense when the brain faced injury or infection. Over the past two decades, however, Barres’ research has revealed that they actually play central roles in sculpting the developing brain, and in guiding neurons’ behavior at every stage of life. “He has made one shocking, revolutionary discovery after another,” says biologist Martin Raff, emeritus professor at University College London, whose own work helped pave the way for those advances. Recently, Barres and his collaborators have made some discoveries that may revolutionize the treatment of neurodegenerative ailments, from glaucoma and multiple sclerosis to Alzheimer’s disease and stroke. What drives such disorders, their findings suggest, is a process in which glia turn from nurturing neurons to destroying them. Human trials of a drug designed to block that change are just beginning.

Keyword: Glia; Learning & Memory
Link ID: 26258 - Posted: 05.22.2019

By Nathaniel Scharping | Don’t get a big head, your mother may have told you. That’s good advice, but it comes too late for most of us. Humans have had big heads, relatively speaking, for hundreds of thousands of years, much to our mothers’ dismay. Our oversize noggins are a literal pain during childbirth. Babies have to twist and turn as they exit the birth canal, sometimes leading to complications that necessitate surgery. And while big heads can be painful for the mother, they can downright transformative for babies: A fetus’ pliable skull deforms during birth like putty squeezed through a tube to allow it to pass into the world. This cranial deformation has been known about for a long time, but in a new study, scientists from France and the U.S. actually watched it happen using an MRI machine during labor. The images, published in a study in PLOS One, show how the skulls (and brains) of seven infants squished and warped during birth to pass through the birth canal. They also shine new light on how much our skulls change shape as we’re born. The researchers recruited pregnant women in France to undergo an MRI a few weeks before pregnancy and another in the minutes before they began to actually give birth. In total, seven women were scanned in the second stage of labor, when the baby begins to make its way out of the uterus. They were then rushed to the maternity ward to actually complete giving birth.

Keyword: Development of the Brain; Brain imaging
Link ID: 26252 - Posted: 05.20.2019

By Benedict Carey “In my head, I churn over every sentence ten times, delete a word, add an adjective, and learn my text by heart, paragraph by paragraph,” wrote Jean-Dominique Bauby in his memoir, “The Diving Bell and the Butterfly.” In the book, Mr. Bauby, a journalist and editor, recalled his life before and after a paralyzing stroke that left him virtually unable to move a muscle; he tapped out the book letter by letter, by blinking an eyelid. Thousands of people are reduced to similarly painstaking means of communication as a result of injuries suffered in accidents or combat, of strokes, or of neurodegenerative disorders such as amyotrophic lateral sclerosis, or A.L.S., that disable the ability to speak. Now, scientists are reporting that they have developed a virtual prosthetic voice, a system that decodes the brain’s vocal intentions and translates them into mostly understandable speech, with no need to move a muscle, even those in the mouth. (The physicist and author Stephen Hawking used a muscle in his cheek to type keyboard characters, which a computer synthesized into speech.) “It’s formidable work, and it moves us up another level toward restoring speech” by decoding brain signals, said Dr. Anthony Ritaccio, a neurologist and neuroscientist at the Mayo Clinic in Jacksonville, Fla., who was not a member of the research group. Researchers have developed other virtual speech aids. Those work by decoding the brain signals responsible for recognizing letters and words, the verbal representations of speech. But those approaches lack the speed and fluidity of natural speaking. The new system, described on Wednesday in the journal Nature, deciphers the brain’s motor commands guiding vocal movement during speech — the tap of the tongue, the narrowing of the lips — and generates intelligible sentences that approximate a speaker’s natural cadence. © 2019 The New York Times Company

Keyword: Language; Robotics
Link ID: 26174 - Posted: 04.25.2019

By Karen Weintraub Stroke, amyotrophic lateral sclerosis and other medical conditions can rob people of their ability to speak. Their communication is limited to the speed at which they can move a cursor with their eyes (just eight to 10 words per minute), in contrast with the natural spoken pace of 120 to 150 words per minute. Now, although still a long way from restoring natural speech, researchers at the University of California, San Francisco, have generated intelligible sentences from the thoughts of people without speech difficulties. The work provides a proof of principle that it should one day be possible to turn imagined words into understandable, real-time speech circumventing the vocal machinery, Edward Chang, a neurosurgeon at U.C.S.F. and co-author of the study published Wednesday in Nature, said Tuesday in a news conference. “Very few of us have any real idea of what’s going on in our mouth when we speak,” he said. “The brain translates those thoughts of what you want to say into movements of the vocal tract, and that’s what we want to decode.” But Chang cautions that the technology, which has only been tested on people with typical speech, might be much harder to make work in those who cannot speak—and particularly in people who have never been able to speak because of a movement disorder such as cerebral palsy. Chang also emphasized that his approach cannot be used to read someone’s mind—only to translate words the person wants to say into audible sounds. “Other researchers have tried to look at whether or not it’s actually possible to decode essentially just thoughts alone,” he says.* “It turns out it’s a very difficult and challenging problem. That’s only one reason of many that we focus on what people are trying to say.” © 2019 Scientific American

Keyword: Brain imaging; Language
Link ID: 26170 - Posted: 04.24.2019

By Kelly Servick The machines that scan our brains are usually monstrous contraptions, locked away in high-end research centers. But smaller, cheaper technologies may soon enter the field, like an MRI scanner built for the battlefield and a lightweight, wearable magnetoencephalography system that records magnetic fields generated by the brains of people in motion. If such devices become widespread, they’ll raise new ethical questions, says Francis Shen, a law professor and neuroethicist at the University of Minnesota (UMN) in Minneapolis and Massachusetts General Hospital in Boston. How should researchers share results with the far-flung populations they may soon be able to study? Could direct-to-consumer neuroimaging become an industry alongside personal genetic testing? With a grant from the federal Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative, Shen has teamed up with three UMN colleagues, including MRI physicist Michael Garwood, to start a conversation about the ethical implications of portable neuroimaging. Garwood is part of a multicenter team building an MRI machine powerful enough to be used in medical diagnostic tests that weighs just 400 kilograms—less than a tenth of traditional scanners. He expects the new scanner to take its first images in 3 years. And if market demand can bring down the cost of a key component, he thinks it could eventually cost $200,000 or less, versus millions of dollars for current scanners. Shen and Garwood discussed the ethical issues at play with Science, after presenting their work at a meeting of BRAIN Initiative investigators last week in Washington, D.C. This interview has been edited for brevity and clarity. © 2019 American Association for the Advancement of Science

Keyword: Brain imaging
Link ID: 26149 - Posted: 04.17.2019

In a study of healthy volunteers, National Institutes of Health researchers found that our brains may solidify the memories of new skills we just practiced a few seconds earlier by taking a short rest. The results highlight the critically important role rest may play in learning. “Everyone thinks you need to ‘practice, practice, practice’ when learning something new. Instead, we found that resting, early and often, may be just as critical to learning as practice,” said Leonardo G. Cohen, M.D., Ph.D., senior investigator at NIH’s National Institute of Neurological Disorders and Stroke and a senior author of the paper published in the journal Current Biology. “Our ultimate hope is that the results of our experiments will help patients recover from the paralyzing effects caused by strokes and other neurological injuries by informing the strategies they use to ‘relearn’ lost skills.” The study was led by Marlene Bönstrup, M.D., a postdoctoral fellow in Dr. Cohen’s lab. Like many scientists, she held the general belief that our brains needed long periods of rest, such as a good night’s sleep, to strengthen the memories formed while practicing a newly learned skill. But after looking at brain waves recorded from healthy volunteers in learning and memory experiments at the NIH Clinical Center, she started to question the idea. The waves were recorded from right-handed volunteers with a highly sensitive scanning technique called magnetoencephalography. The subjects sat in a chair facing a computer screen and under a long cone-shaped brain scanning cap. The experiment began when they were shown a series of numbers on a screen and asked to type the numbers as many times as possible with their left hands for 10 seconds; take a 10 second break; and then repeat this trial cycle of alternating practice and rest 35 more times. This strategy is typically used to reduce any complications that could arise from fatigue or other factors.

Keyword: Learning & Memory; Brain imaging
Link ID: 26137 - Posted: 04.13.2019

By Kelly Servick At age 16, Danielle Bassett spent most of her day at the piano, trying to train her fingers and ignoring a throbbing pain in her forearms. She hoped to pursue a career in music and had been assigning herself relentless practice sessions. But the more she rehearsed Johannes Brahms's feverish Rhapsody in B Minor on her family's Steinway, the clearer it became that something was wrong. Finally, a surgeon confirmed it: Stress fractures would force her to give up the instrument for a year. "What was left in my life was rather bleak," Bassett says. Her home-schooled upbringing in rural central Pennsylvania had instilled a love of math, science, and the arts. But by 17, discouraged by her parents from attending college and disheartened at her loss of skill while away from the keys, she expected that responsibilities as a housewife and mother would soon eclipse any hopes of a career. "I wasn't happy with that plan," she says. Instead, Bassett catapulted herself into a life of research in a largely uncharted scientific field now known as network neuroscience. A Ph.D. physicist and a MacArthur fellow by age 32, she has pioneered the use of concepts from physics and math to describe the dynamic connections in the human brain. "She's now the doyenne of network science," says theoretical neuroscientist Karl Friston of University College London. "She came from a formal physics background but was … confronted with some of the deepest questions in neuroscience." © 2019 American Association for the Advancement of Science.

Keyword: Brain imaging; Development of the Brain
Link ID: 26133 - Posted: 04.12.2019

By Lydia Denworth The vast majority of neuroscientific studies contain three elements: a person, a cognitive task and a high-tech machine capable of seeing inside the brain. That simple recipe can produce powerful science. Such studies now routinely yield images that a neuroscientist used to only dream about. They allow researchers to delineate the complex neural machinery that makes sense of sights and sounds, processes language and derives meaning from experience. But something has been largely missing from these studies: other people. We humans are innately social, yet even social neuroscience, a field explicitly created to explore the neurobiology of human interaction, has not been as social as you would think. Just one example: no one has yet captured the rich complexity of two people’s brain activity as they talk together. “We spend our lives having conversation with each other and forging these bonds,” neuroscientist Thalia Wheatley of Dartmouth College says. “[Yet] we have very little understanding of how it is people actually connect. We know almost nothing about how minds couple.” That is beginning to change. A growing cadre of neuroscientists is using sophisticated technology—and some very complicated math—to capture what happens in one brain, two brains, or even 12 or 15 at a time when their owners are engaged in eye contact, storytelling, joint attention focused on a topic or object, or any other activity that requires social give and take. Although the field of interactive social neuroscience is in its infancy, the hope remains that identifying the neural underpinnings of real social exchange will change our basic understanding of communication and ultimately improve education or inform treatment of the many psychiatric disorders that involve social impairments. © 2019 Scientific American

Keyword: Brain imaging
Link ID: 26128 - Posted: 04.11.2019

By Gretchen Vogel A research group’s claimed ability to communicate with completely paralyzed people has come under fire, prompting research misconduct investigations at a German university and at Germany’s main research agency, the German Research Foundation (DFG). Two years ago, researchers in Germany and Switzerland claimed that by analyzing blood flow in different parts of the brain with an electronic skullcap, they could elucidate answers to yes or no questions from completely paralyzed people. The find, published in PLOS Biology in 2017, raised hopes for patients with degenerative diseases like amyotrophic lateral sclerosis that ultimately leave them without any voluntary muscle control—not even the ability to blink or move their eyes—a condition called a “completely locked-in state.” Now, a simmering controversy about the paper has erupted into public view. As first reported by the German newspaper Süddeutsche Zeitung, PLOS Biology yesterday published a critique of the paper that claims the authors’ statistical analysis is incorrect. Martin Spüler, an informatics specialist at the Eberhard Karls University of Tübingen in Germany, says his analysis of the data shows no support for the authors’ claim that their system could allow patients to answer questions correctly 70% of the time. His critique, first raised in late 2017, has prompted investigations of possible scientific misconduct at both DFG and the University of Tübingen, where the group studying locked-in patients is also based. © 2019 American Association for the Advancement of Science.

Keyword: Consciousness; Brain imaging
Link ID: 26127 - Posted: 04.11.2019

By Emily Mullin About noon most days, the Lieber Institute for Brain Development in East Baltimore gets a case — that is, a brain. It arrives in an inconspicuous red cooler. Almost immediately, resident neuropathologist Rahul Bharadwaj gets to work, carefully inspecting it for any abnormalities, such as tumors or lesions. Often, the brains come from the Maryland Medical Examiner’s Office, just a 15-minute drive across town. On other days, they are flown in — packed on dry ice — from around the country. Since opening in 2011, the institute has amassed more than 3,000 of these post-mortem brains that they are studying to better understand the biological mechanisms behind such neuropsychiatric disorders as schizophrenia, major depression, substance abuse, bipolar disorder and post-traumatic stress disorder. About 100 brain banks exist across the country for all sorts of brain diseases. But Lieber, founded with the support and funding of a wealthy couple whose daughter suffered a psychotic break in her 20s, is the biggest collection dedicated specifically to mental conditions. Current therapies for neuropsychiatric disorders — antipsychotics and antidepressants — treat symptoms rather than the underlying cause of illness, which remains largely unknown. And while they can be lifesaving for certain people, they can cause unpleasant and sometimes serious side effects. In some cases, they won't work at all. Most of these drugs were also discovered by accident. Lieber’s goal is to unravel what happens biologically in the brain to make these conditions occur and then to develop therapies to treat these conditions at their root cause, or even prevent them from happening in the first place. © 1996-2019 The Washington Post

Keyword: Brain imaging; Schizophrenia
Link ID: 26121 - Posted: 04.08.2019

Corey Hill Allen and Eyal Aharoni Brain evidence is playing an increasing role in criminal trials in the United States. An analysis indicates that brain evidence such as MRI or CAT scans – meant to provide proof of abnormalities, brain damage or disorder in defendants – was used for leniency in approximately 5 percent of murder cases at the appellate level. This number jumps to an astounding 25 percent in death penalty trials. In these cases, the evidence is meant to show that the defendant lacked the capacity to control his action. In essence, “My brain made me do it.” But does evidence of neurobiological disorder or abnormality tend to help or hurt the defendant? Legal theorists have previously portrayed physical evidence of brain dysfunction as a double-edged sword. On the one hand, it might decrease a judge’s or juror’s desire to punish by minimizing the offender’s perceived responsibility for his transgressions. The thinking would be that the crime resulted from disordered brain activity, not any choice on the part of the offender. On the other hand, brain evidence could increase punitive motivations toward the offender by making him seem more dangerous. That is, if the offender’s brain truly “made him” commit the crime, there is an increased risk such behavior could occur again, even multiple times, in the future. To tease apart these conflicting motivations, our team of cognitive neuroscientists, a medical bioethicist and a philosopher investigated how people tend to weigh neurobiological evidence when deciding on criminal sentences. © 2010–2019, The Conversation US, Inc.

Keyword: Brain imaging; Consciousness
Link ID: 26111 - Posted: 04.03.2019

By Adrian Cho BOSTON—MRI scanners can map a person's innards in exquisite detail, but they say little about composition. Now, physicists are pushing MRI to a new realm of sensitivity to trace specific biomolecules in tissues, a capability that could aid in diagnosing Alzheimer's and other diseases. The advance springs not from improved scanners, but from better methods to solve a notoriously difficult math problem and extract information already latent in MRI data. The new techniques, described this month at a meeting of the American Physical Society here, could soon make the jump to the clinic, says Shannon Kolind, a physicist at the University of British Columbia (UBC) in Vancouver, Canada, who is using them to study multiple sclerosis (MS). "I don't think I'm being too optimistic to say that will happen in the next 5 years," she says. Sean Deoni, a physicist at Brown University, says that "any scanner on the planet can do this." An MRI scanner uses magnetic fields and radio waves to tickle the nuclei of hydrogen atoms—protons—in molecules of water, which makes up more than half of soft tissue. The protons act like little magnets, and the scanner's strong magnetic field makes them all point in one direction. A pulse of radio waves then tips the protons away from the magnetic field, causing them to twirl en masse, like so many gyroscopes. The protons then radiate radio waves of their own. © 2019 American Association for the Advancement of Scienc

Keyword: Brain imaging; Multiple Sclerosis
Link ID: 26059 - Posted: 03.21.2019

Nicola Davis “Acting is the least mysterious of all crafts,” Marlon Brando once said. But for scientists, working out what is going on in an actor’s head has always been something of a puzzle. Now, researchers have said thespians show different patterns of brain activity depending on whether they are in character or not. Dr Steven Brown, the first author of the research from McMaster University in Canada, said: “It looks like when you are acting, you are suppressing yourself; almost like the character is possessing you.” Character building and what makes a truly great actor Read more Writing in the journal Royal Society Open Science, Brown and colleagues report how 15 method actors, mainly theatre students, were trained to take on a Shakespeare role – either Romeo or Juliet – in a theatre workshop, and were asked various questions, to which they responded in character. They were then invited into the laboratory, where their brains were scanned in a series of experiments. Once inside the MRI scanner, the actors were asked to think about their response to a number of fresh conundrums that flashed up on screen, and which might well have occurred to the star-crossed lovers, such as: would they gatecrash a party? And would they tell their parents that they had fallen in love? Each actor was asked to respond to different questions, based on four different premises assigned in a random order. In one, they were asked for their own perspective; in another, they were asked to say how they thought a particular close friend would react, while in a third, they were asked to respond as though they were either Romeo or Juliet. = © 2019 Guardian News & Media Limited

Keyword: Attention; Brain imaging
Link ID: 26029 - Posted: 03.13.2019

Assessing the patterns of energy use and neuronal activity simultaneously in the human brain improves our understanding of how alcohol affects the brain, according to new research by scientists at the National Institutes of Health. The new approach for characterizing brain energetic patterns could also be useful for studying other neuropsychiatric diseases. A report of the findings is now online in Nature Communications. “The brain uses a lot of energy compared to other body organs, and the association between brain activity and energy utilization is an important marker of brain health,” said George F. Koob, Ph.D., director of the National Institute on Alcohol Abuse and Alcoholism (NIAAA), part of NIH, which funded the study. “This study introduces a new way of characterizing how brain activity is related to its consumption of glucose, which could be very useful in understanding how the brain uses energy in health and disease.” The research was led by Dr. Ehsan Shokri-Kojori and Dr. Nora D. Volkow of the NIAAA Laboratory of Neuroimaging. Dr. Volkow is also the director of the National Institute on Drug Abuse at NIH. In previous studies they and their colleagues have shown that alcohol significantly affects brain glucose metabolism, a measure of energy use, as well as regional brain activity, which is assessed through changes in blood oxygenation. “The findings from this study highlight the relevance of energetics for ensuring normal brain function and reveal how it is disrupted by excessive alcohol consumption,” says Dr. Volkow.

Keyword: Drug Abuse; Brain imaging
Link ID: 26004 - Posted: 03.05.2019

Laura Sanders A conscious brain hums with elaborate, interwoven signals, a study finds. Scientists uncovered that new signature of consciousness by analyzing brain activity of healthy people and of people who were not aware of their surroundings. The result, published online February 6 in Science Advances, makes headway on a tough problem: how to accurately measure awareness in patients who can’t communicate. Other methods for measuring consciousness have been proposed, but because of its size and design, the new study was able to find a particularly strong signal. Conducted by an international team of researchers spanning four countries, the effort “produced clear, reliable results that are directly relevant to the clinical neuroscience of consciousness,” says cognitive neuroscientist Michael Pitts of Reed College in Portland, Ore. Consciousness — and how the brain creates it — is a squishy concept. It slips away when we sleep, and can be distorted by drugs or lost in accidents. Though scientists have proposed many biological explanations for how our brains create consciousness, a full definition still eludes scientists. By finding a clear brain signature of awareness, the new work “bring us closer to understanding what consciousness is,” says study coauthor Jacobo Sitt of INSERM in Paris. © Society for Science & the Public 2000 - 2019.

Keyword: Consciousness; Brain imaging
Link ID: 25943 - Posted: 02.09.2019

Ruth Williams The brains of people in vegetative, partially conscious, or fully conscious states have differing profiles of activity as revealed by functional magnetic resonance imaging (fMRI), according to a report today (February 6) in Science Advances. The results of the study indicate that, compared with patients lacking consciousness, the brains of healthy individuals exhibit highly dynamic and complex connectivity. “This new study provides a substantial advance in characterizing the ‘fingerprints’ of consciousness in the brain” Anil Seth, a neuroscientist at the University of Sussex, UK, who was not involved in the project, writes in an email to The Scientist. “It opens new doors to determining conscious states—or their absence—in a range of different conditions.” A person can lose consciousness temporarily, such as during sleep or anesthesia, or more permanently as is the case with certain brain injuries. But while unconsciousness manifests behaviorally as a failure to respond to stimuli, such behavior is not necessarily the result of unconsciousness. Some seemingly unresponsive patients, for example, can display brain activities similar to those of fully conscious individuals when asked to imagine performing a physical task such as playing tennis. Such a mental response in the absence of physical feedback is a condition known as cognitive-motor dissociation. Researchers are therefore attempting to build a better picture of what is happening in the human brain during consciousness and unconsciousness. In some studies, electroencephalography (EEG) recordings of the brain’s electrical activities during sleep, under anesthesia, or after brain injury have revealed patterns of brain waves associated with consciousness. But, says Jacobo Sitt of the Institute of Brain and Spinal Cord in Paris, such measurements do not provide good spatial information about brain activity. With fMRI, on the other hand, “we know where the activity is coming from.” © 1986 - 2019 The Scientist.

Keyword: Consciousness; Brain imaging
Link ID: 25941 - Posted: 02.08.2019

Jon Hamilton Women tend to have more youthful brains than their male counterparts — at least when it comes to metabolism. While age reduces the metabolism of all brains, women retain a higher rate throughout the lifespan, researchers reported Monday in the journal Proceedings of the National Academy of Sciences. "Females had a younger brain age relative to males," says Dr. Manu Goyal, an assistant professor of radiology and neurology at Washington University School of Medicine in St. Louis. And that may mean women are better equipped to learn and be creative in later life, he says. The finding is "great news for many women," says Roberta Diaz Brinton, who wasn't connected with the study and directs the Center for Innovation in Brain Science at the University of Arizona Health Sciences. But she cautions that even though women's brain metabolism is higher overall, some women's brains experience a dramatic metabolic decline around menopause, leaving them vulnerable to Alzheimer's. The study came after Goyal and a team of researchers studied the brain scans of 205 people whose ages ranged from 20 to 82. Positron emission tomography scans of these people assessed metabolism by measuring how much oxygen and glucose was being used at many different locations in the brain. The team initially hoped to use the metabolic information to predict a person's age. So they had a computer study how metabolism changed in both men and women. © 2019 npr

Keyword: Sexual Behavior; Brain imaging
Link ID: 25933 - Posted: 02.05.2019