Chapter 3. Neurophysiology: The Generation, Transmission, and Integration of Neural Signals

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By Lauren Aguirre, STAT Scientists who study Alzheimer’s disease have mostly ignored the role of seizures, but that is beginning to change, and new research suggests they may provide insight into the progression of the disease and pave the way for treatments. It’s no surprise to neurologists that some people experience convulsive seizures in the later stages of the disease. In fact, the second patient ever to receive an Alzheimer’s diagnosis more than a century ago suffered from them. But because brain damage can cause seizures, they were long thought to be just one more casualty of a deteriorating brain. Now evidence is accumulating that such abnormal electrical activity is far more common and occurs much earlier—and perhaps even precedes obvious signs of memory loss. This raises the possibility that seizures may be intimately tied up with the progression of the disease. New research that lends credence to this hypothesis was shared at the Alzheimer’s Association International Conference in Los Angeles this week. One study looked at 55 patients between the ages of 50 and 69 who were admitted to an Israeli medical center with their first known seizure. A quarter of them went on to develop dementia—with a mean time to the diagnosis of eight and a half years. Another study of nearly 300,000 U.S. veterans over the age of 55 found that seizures were associated with twice the risk for developing dementia between one and nine years later. © 2019 Scientific American,

Keyword: Alzheimers; Epilepsy
Link ID: 26441 - Posted: 07.23.2019

By Carl Zimmer In a laboratory at the Stanford University School of Medicine, the mice are seeing things. And it’s not because they’ve been given drugs. With new laser technology, scientists have triggered specific hallucinations in mice by switching on a few neurons with beams of light. The researchers reported the results on Thursday in the journal Science. The technique promises to provide clues to how the billions of neurons in the brain make sense of the environment. Eventually the research also may lead to new treatments for psychological disorders, including uncontrollable hallucinations. “This is spectacular — this is the dream,” said Lindsey Glickfeld, a neuroscientist at Duke University, who was not involved in the new study. In the early 2000s, Dr. Karl Deisseroth, a psychiatrist and neuroscientist at Stanford, and other scientists engineered neurons in the brains of living mouse mice to switch on when exposed to a flash of light. The technique is known as optogenetics. In the first wave of these experiments, researchers used light to learn how various types of neurons worked. But Dr. Deisseroth wanted to be able to pick out any individual cell in the brain and turn it on and off with light. So he and his colleagues designed a new device: Instead of just bathing a mouse’s brain in light, it allowed the researchers to deliver tiny beams of red light that could strike dozens of individual brain neurons at once. To try out this new system, Dr. Deisseroth and his colleagues focused on the brain’s perception of the visual world. When light enters the eyes — of a mouse or a human — it triggers nerve endings in the retina that send electrical impulses to the rear of the brain. There, in a region called the visual cortex, neurons quickly detect edges and other patterns, which the brain then assembles into a picture of reality. © 2019 The New York Times Company

Keyword: Vision
Link ID: 26433 - Posted: 07.19.2019

By Denise Grady The actor Cameron Boyce, 20, who died on Saturday, had epilepsy, and his death was caused by a seizure that occurred during his sleep, his family said in a statement. Mr. Boyce starred in shows on the Disney Channel, including “Descendants” and “Jessie,” and appeared in a number of movies. “Cameron’s tragic passing was due to a seizure as a result of an ongoing medical condition, and that condition was epilepsy,” a Boyce family spokesperson told ABC News in a statement on Tuesday night. The Los Angeles County coroner’s office conducted an autopsy, but said it was awaiting the results of additional tests before determining an official cause of death. The most likely cause of his death was Sudep, or sudden unexpected death in epilepsy, said Dr. Orrin Devinsky, director of NYU Langone’s Comprehensive Epilepsy Center in Manhattan. He was not involved in Mr. Boyce’s care. Each year, about one in 1,000 people with epilepsy die from this disorder. In the United States, there are about 2,600 such deaths a year, though neurologists suspect that figure is an undercount. “It can happen to anyone with epilepsy,” Dr. Devinsky said. “Even the first seizure could be the last one. The more uncontrolled the seizures, the more severe, and the more they occur in sleep, the higher the risk.” About 70 percent of cases occur during sleep, and the people are often found facedown in bed. Usually, they have been sleeping alone. The probable cause of death is that the person stops breathing. A severe seizure can temporarily shut down the brain, including the centers that control respiration, Dr. Devinsky said. © 2019 The New York Times Company

Keyword: Epilepsy
Link ID: 26408 - Posted: 07.11.2019

Two nationally renowned neurosurgeons at Washington University School of Medicine in St. Louis will present “BrainWorks,” a live theatrical performance that explores the wonders of the human brain by dramatizing real-life neurological cases. The performance, comprised of four one-act plays, will debut July 19-21 at the Loretto-Hilton Center for the Performing Arts at Webster University. Albert Kim, PhD, MD, associate professor of neurological surgery, and Eric C. Leuthardt, MD, professor of neurological surgery, will guide the audience through each scene as they explain the mysteries of the human brain and the neuroscience of diseases such as Alzheimer’s disease, epilepsy, brain tumors and stroke. Kim and Leuthardt teamed up with playwrights from the New Dramatists to write each one-act play; the scenarios are based on patients the doctors have treated. “We have involved conversations about what’s going to happen – the course of treatment, the risks and benefits,” Kim said. “We also ensure the families become involved in those conversations. Together, the patient and family members become a part of the process that transforms and heals them. It’s this kind of conversation we want to bring to others through ‘BrainWorks.’” ©2019 Washington University in St. Louis

Keyword: Alzheimers; Epilepsy
Link ID: 26386 - Posted: 07.04.2019

By Ryan Dalton In the dystopian world of George Orwell’s Nineteen Eighty-Four, the government of Oceania aims to achieve thought control through the restriction of language. As explained by the character ‘Syme’, a lexicologist who is working to replace the English language with the greatly-simplified ‘Newspeak’: “Don’t you see that the whole aim of Newspeak is to narrow the range of thought?” While Syme’s own reflections were short-lived, the merits of his argument were not: the words and structure of a language can influence the thoughts and decisions of its speakers. This holds for English and Greek, Inuktitut and Newspeak. It also may hold for the ‘neural code’, the basic electrical vocabulary of the neurons in the brain. Neural codes, like spoken languages, are tasked with conveying all manner of information. Some of this information is immediately required for survival; other information has a less acute use. To accommodate these different needs, a balance is struck between the richness of information being transferred and the speed or reliability with which it is transferred. Where the balance is set depends on context. In the example of language, the mention of the movie Jaws at a dinner party might result in a ranging and patient—if disconcerting—discussion around the emotional impact of the film. In contrast, the observation of a dorsal fin breaking through the surf at the beach would probably elicit a single word, screamed by many beachgoers at once: “shark!” In one context, the language used has been optimized for richness; in the other, for speed and reliability. © 2019 Scientific American

Keyword: Language
Link ID: 26383 - Posted: 07.03.2019

Strobe lighting at music festivals can increase the risk of epileptic seizures, researchers have warned. The Dutch team said even people who have not been diagnosed with epilepsy might be affected. Their study was prompted by the case of a 20-year-old, with no history of epilepsy, who suddenly collapsed and had a fit at a festival. The Epilepsy Society said festivals should limit lighting to the recommended levels. Epilepsy is a condition that affects the brain. There are many types, and it can start at any age. Around 3% of people with epilepsy are photosensitive, which means their seizures are triggered by flashing or flickering lights, or patterns. The Health and Safety Executive recommends strobe lighting should be kept to a maximum of four hertz (four flashes per second) in clubs and at public events. 'Life-affirming' The researchers studied electronic dance music festivals because they often use strobe lighting. They looked at data on people who needed medical care among the 400,000 visitors to 28 day and night-time dance music festivals across the Netherlands in 2015. The figures included 241,000 people who were exposed to strobe lights at night-time festivals. Thirty people at night-time events with strobe lighting had a seizure, compared with nine attending daytime events. The team, led by Newel Salet of the VU Medical Centre in Amsterdam, writing in BMJ Open, said other factors could increase the risk of seizures. But they added: "Regardless of whether stroboscopic lights are solely responsible or whether sleep deprivation and/or substance abuse also play a role, the appropriate interpretation is that large [electronic dance music] festivals, especially during the night-time, probably cause at least a number of people per event to suffer epileptic seizures." They advise anyone with photosensitive epilepsy to either avoid such events or to take precautionary measures, such as getting enough sleep and not taking drugs, not standing close to the stage, and leaving quickly if they experience any "aura" effects. © 2019 BBC

Keyword: Epilepsy; Vision
Link ID: 26323 - Posted: 06.12.2019

By MOISES VELASQUEZ-MANOFF When Catherine Jacobson first heard about the promise of cannabis, she was at wits’ end. Her 3-year-old son, Ben, had suffered from epileptic seizures since he was 3 months old, a result of a brain malformation called polymicrogyria. Over the years, Jacobson and her husband, Aaron, have tried giving him at least 16 different drugs, but none provided lasting relief. They lived with the grim prognosis that their son — whose cognitive abilities never advanced beyond those of a 1-year-old — would likely continue to endure seizures until the cumulative brain injuries led to his death. In early 2012, when Jacobson learned about cannabis at a conference organized by the Epilepsy Therapy Project, she felt a flicker of hope. The meeting, in downtown San Francisco, was unlike others she had attended, which were usually geared toward lab scientists and not directly focused on helping patients. This gathering aimed to get new treatments into patients’ hands as quickly as possible. Attendees weren’t just scientists and people from the pharmaceutical industry. They also included, on one day of the event, families of patients with epilepsy. The tip came from a father named Jason David, with whom Jacobson began talking by chance outside a presentation hall. He wasn’t a presenter or even very interested in the goings-on at the conference. He had mostly lost faith in conventional medicine during his own family’s ordeal. But he claimed to have successfully treated his son’s seizures with a cannabis extract, and now he was trying to spread the word to anyone who would listen. The idea to try cannabis extract came to David after he found out that the federal government held a patent on cannabidiol, a molecule derived from the cannabis plant that is commonly referred to as CBD. Unlike the better-known marijuana molecule delta-9-tetrahydrocannabinol, or THC, CBD isn’t psychoactive; it doesn’t get users high. But in the late 1990s, scientists at the National Institutes of Health discovered that it could produce remarkable medicinal effects. In test tubes, the molecule shielded neurons from oxidative stress, a damaging process common in many neurological disorders, including epilepsy.

Keyword: Drug Abuse; Epilepsy
Link ID: 26236 - Posted: 05.15.2019

By Benedict Carey The research on brain stimulation is advancing so quickly, and the findings are so puzzling, that a reader might feel tempted to simply pre-order a genius cap from Amazon, to make sense of it all later. In just the past month, scientists reported enhancing the working memory of older people, using electric current passed through a skullcap, and restoring some cognitive function in a brain-damaged woman, using implanted electrodes. Most recently, the Food and Drug Administration approved a smartphone-size stimulator intended to alleviate attention-deficit problems by delivering electric current through a patch placed on the forehead. Last year, another group of scientists announced that they, too, had created a brain implant that boosts memory storage. All the while, a do-it-yourself subculture continues to grow, of people who are experimenting with placing electrodes in their skulls or foreheads for brain “tuning.” Predicting where all these efforts are headed, and how and when they might converge in a grand methodology, is an exercise in rank speculation. Neuro-stimulation covers too many different techniques, for various applications and of varying quality. About the only certainties are the usual ones: that a genius cap won’t arrive anytime soon, and that any brain-zapping gizmo that provides real benefit also is likely to come with risk. Nevertheless, the field is worth watching because it hints at some elementary properties of brain function. Unlike psychiatric drugs, or psychotherapy, pulses of current can change people’s behavior very quickly, and reliably. Turn the current on and things happen; turn it off and the effect stops or tapers. © 2019 The New York Times Company

Keyword: Learning & Memory; Alzheimers
Link ID: 26232 - Posted: 05.14.2019

By Kelly Servick For a hair-thin probe penetrating the brain to listen in on neurons' electrical chatter, finesse is key. It's easy to rip tissue on the way in. And once in place, a probe can do further damage that muffles the signals it aims to detect. But recent reports describe a generation of finer probes that should prove less damaging. Just a few micrometers thick—comparable to neurons themselves—these tools may soon capture unprecedented long-term recordings from hard-to-reach parts of animal brains. And they may lead to more sophisticated brain-computer interfaces for people. Improved material fabrication techniques have helped labs create the exquisitely fine probes, says neural engineer Timothy Hanson, who developed a system for inserting tiny electrodes while at the University of California, San Francisco (UCSF). And lab tests have shown that brain research using ultrasmall electrodes "can be done, and that it's worthwhile." Conventional brain probes are already vanishingly tiny. Stiff electrodes known as Michigan probes, commonly used in neuroscience research, are pointed, ribbonlike shafts that can be as thin as 15 micrometers and are usually 60 micrometers wide or more. In a standard grid known as the Utah array, each spike is roughly 200 micrometers thick at its base. But in the months after either device is implanted, its connection to neurons typically weakens and its signal fades. A key reason is that the probe provokes an immune reaction in the brain. Its initial plunge into the tissue can tear blood vessels. And even after that damage heals, the probe continues to push and pull on surrounding tissue. In response, nonneuronal cells called glia multiply and form scars that push neurons away from the electrode. © 2019 American Association for the Advancement of Science.

Keyword: Brain imaging
Link ID: 26200 - Posted: 05.02.2019

James Hamblin The past two weeks have been frenetic for Bre Hushaw, who is now known to millions of people as the girl in the depression helmet. Hushaw has been hearing from people all around the world who want to try it, or at least want to know how it works. Her life as a meme began when she agreed to an on-camera interview with the local-news site AZfamily.com for a story headlined “Helmet Approved by FDA to Treat Depression Available in Arizona.” The feel-good tale of Hushaw’s miraculous recovery from severe depression was tossed into the decontextualizing maw of the internet and distilled down to a screenshot of a young woman looking like a listless Stormtrooper. Jokes poured in. Some of the most popular, each with more than 100,000 likes on Twitter, include: “If u see me with this ugly ass helmet mind ur business.” “Friend: hey everything alright? Me, wearing depression helmet: yeah I’m just tired.” “The depression helmet STAYS ON during sex.” Hushaw has been tracking the virality, sometimes cringing and sometimes laughing. She replies to as many serious inquiries as she can, while finishing up her senior year at Northern Arizona University before starting a job in marketing. A year ago, she didn’t think she was going to live to graduation. When she was 10 years old, her mother died. Her depression symptoms waxed and waned from then on, and they waxed especially when she heard the gunshots on her campus during a shooting at the school in 2015. She’s tried many medications over the years—14, by her count. (c) 2019 by The Atlantic Monthly Group.

Keyword: Depression
Link ID: 26163 - Posted: 04.22.2019

By Benedict Carey More than 3 million Americans live with disabling brain injuries. The vast majority of these individuals are lost to the medical system soon after their initial treatment, to be cared for by family or to fend for themselves, managing fatigue, attention and concentration problems with little hope of improvement. On Saturday, a team of scientists reported a glimmer of hope. Using an implant that stimulates activity in key areas of the brain, they restored near-normal levels of brain function to a middle-aged woman who was severely injured in a car accident 18 years ago. Experts said the woman was a test case, and that it was far from clear whether the procedure would prompt improvements for others like her. That group includes an estimated 3 million to 5 million people, many of them veterans of the wars in Iraq and Afghanistan, with disabilities related to traumatic brain injuries. “This is a pilot study,” said Dr. Steven R. Flanagan, the chairman of the department of rehabilitation medicine at NYU Langone Health, who was not part of the research team. “And we certainly cannot generalize from it. But I think it’s a very promising start, and there is certainly more to come in this work.” The woman, now in her early 40s, was a student when the accident occurred. She soon recovered sufficiently to live independently. But she suffered from persistent fatigue and could not read or concentrate for long, leaving her unable to hold a competitive job, socialize much, or resume her studies. “Her life has changed,” said Dr. Nicholas Schiff, a professor of neurology and neuroscience at Weill Cornell Medicine and a member of the study team. “She is much less fatigued, and she’s now reading novels. The next patient might not do as well. But we want keep going to see what happens.” © 2019 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 26142 - Posted: 04.15.2019

Alix Spiegel Our thoughts and fears, movements and sensations all arise from the electrical blips of billions of neurons in our brain. Streams of electricity flow through neural circuits to govern these actions of the brain and body, and some scientists think that many neurological and psychiatric disorders may result from dysfunctional circuits. As this understanding has grown, some scientists have asked whether we could locate these faulty circuits, reach deep into the brain and nudge the flow to a more functional state, treating the underlying neurobiological cause of ailments like tremors or depression. The idea of changing the brain for the better with electricity is not new, but deep brain stimulation takes a more targeted approach than the electroconvulsive therapy introduced in the 1930s. DBS seeks to correct a specific dysfunction in the brain by introducing precisely timed electric pulses to specific regions. It works by the action of a very precise electrode that is surgically inserted deep in the brain and typically controlled by a device implanted under the collarbone. Once in place, doctors can externally tailor the pulses to a frequency that they hope will fix the faulty circuit. This week's Invisibilia podcast features the story of a woman with obsessive-compulsive disorder and depression who signed up for a deep brain stimulation trial. The story describes what it's like to be able to adjust her mood by adjusting the settings on her device. Listen to that story here. © 2019 npr

Keyword: Depression; Emotions
Link ID: 26096 - Posted: 03.30.2019

Alix Spiegel We have the story of one woman who is taking part in an experiment on deep brain stimulation. RACHEL MARTIN, HOST: We are about to go deep - deep into your brain. STEVE INSKEEP, HOST: With a story about deep brain stimulation, or DBS, which sounds like a kind of massage, actually. But it means that patients get an implant that delivers small pulses of electricity to their brains. MARTIN: It's often used to treat Parkinson's disease. But for years, researchers have been trying to figure out how to use it to treat psychiatric disorders. INSKEEP: Results and experiments so far have been mixed. Many patients see no benefit. But some with obsessive-compulsive disorder have seen big changes. MARTIN: Like the next woman you're going to meet. For privacy, we are withholding her last name. Alix Spiegel from NPR's INVISIBILIA has her story. ALIX SPIEGEL, BYLINE: During the appointment, Megan didn't have to do that much, just sit in a chair while one of the doctors from the experiment used what looked like an oversized remote control to reprogram her electricity levels. Even after five years of having the implant, getting her electricity adjusted was unpredictable. Sometimes it went fine. But having electrodes in your brain is really complicated. And occasionally, the adjustments didn't go well. UNIDENTIFIED DOCTOR: While you were talking, I slowly ramped it up again. Anything different now? MEGAN: Slightly more aware. UNIDENTIFIED DOCTOR: OK. MEGAN: It's not like in the past, where it was like, oh, I feel good. But it's, like, a different feeling. SPIEGEL: After the doctor turned her up higher, Megan said she felt better. But then he decided to dial it back just a notch. He was worried that too much electricity might make her manic. UNIDENTIFIED DOCTOR: Now, if you notice me turning it down, then maybe I'll change my mind on that. MEGAN: (Crying) I'm sorry; don't do it. UNIDENTIFIED DOCTOR: Did you just feel it? MEGAN: (Crying) I don't feel very good at all right now. © 2019 npr

Keyword: Depression
Link ID: 26095 - Posted: 03.30.2019

By James Gallagher Health and science correspondent, BBC News French scientists say they have proof that dogs can pick up the smell of an epileptic seizure. The University of Rennes team hope the findings could lead to ways to predict when people will have a seizure. These could include dogs or "electronic noses" that pick up the precise odour being given off during a seizure. Dogs have previously been shown to be able to sniff out diseases including cancers, Parkinson's, malaria and diabetes. Some people with epilepsy already rely on the animals. One sleeping in a child's bedroom can alert family members of a seizure in the middle of the night. The latest study, in the journal Scientific Reports, trained five dogs from Medical Mutts, in the US, to recognise the smell of sweat taken from a patient having a seizure. They were then given a choice of seven sweat samples taken from other patients while they were either relaxing, exercising or having a seizure. Two of the dogs found the seizure sample about two-thirds of the time and the other three were 100% accurate The report says: "The results are extremely clear and constitute a first step towards identifying a seizure-specific odour." © 2019 BBC

Keyword: Chemical Senses (Smell & Taste); Epilepsy
Link ID: 26091 - Posted: 03.29.2019

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

Hadley Freeman Like everyone else at this point, I have many questions about Brexit, starting with “why” and going from there. For example: are concerns about how Britain is going to cope merely “project fear”, as some Brexity folk still have it? Is it going to be like the blitz, as other Brexity people have promised enthusiastically? Such people include someone called Ant Middleton from Channel 4’s SAS: Who Dares Wins, who said last year in a tweet (since deleted): “A ‘no deal’ for our country would actually be a blessing in disguise. It would force us into hardship and suffering which would unite & bring us together, bringing back British values of loyalty and a sense of community!” Truly, there are few things as touching as a grown man playing soldiers by waxing nostalgic for a time he didn’t live through. And by “touching” I mean “nauseating”. I try to avoid writing about Brexit for the same reason I avoid eating my hair: you just end up choking on the pointlessness of it all. But one question has become too pressing to ignore: just how self-centred do you have to be to think the risk of making it harder for people to get necessary medications is an irrelevant niggle while you achieve your masturbatory fantasy of “sovereignty”? Sure, talk of insulin supplies, say, is a bummer when you are entertaining dreams of sailing victoriously back from Brussels beneath a St George’s flag, like George Washington crossing the Delaware in Emanuel Leutze’s painting, only less American (although, given that our supermarkets may soon be stuffed with chlorinated chicken from the US, maybe not). But for those who have long been dependent on certain drugs, these niggly questions make a no-deal Brexit less of a blessing in disguise. © 2019 Guardian News & Media Limited

Keyword: Epilepsy
Link ID: 26020 - Posted: 03.09.2019

Bret Stetka As the story goes, nearly 80 years ago on the Faroe Islands - a stark North Atlantic archipelago 200 miles off the coast of Scotland — a neurologic epidemic may have washed, or rather convoyed, ashore. Before 1940 the incidence of multiple sclerosis on the Faroes was near, if not, zero, according to the tantalizing lore I recall from medical school. Yet in the years following British occupation of the islands during World War II, the rate of MS rose dramatically, leading many researchers to assume the outbreak was caused by some unknown germ transmitted by the foreign soldiers. We now know that MS is not infectious in the true sense of the word. It is not contagious in the way, say, the flu is. But infection does likely play a role in MS. As may be the case in Alzheimer's disease, it's looking more and more like MS strikes when infectious, genetic and immune factors gang up to eventually impair the function of neurons in the brain and spinal cord. Researchers are hoping to better understand this network of influences to develop more effective ways to treat MS, and perhaps prevent it in the first place. In the MS-free brain, electrical impulses zip down nerve fibers called axons causing the release of neurotransmitters. The wiring allows neurons to communicate with each other and generate biologic wonders like thought, sensation and movement. In many regions of the brain those axons are encased in an insulating jacket of protein and fat called myelin, which increases the speed that electrical nerve impulses travel. © 2019 npr

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 25893 - Posted: 01.22.2019

Laura Sanders Using laser light, ballooning tissue and innovative genetic tricks, scientists are starting to force brains to give up their secrets. By mixing and matching powerful advances in microscopy and cell biology, researchers have imaged intricate details of individual nerve cells in fruit flies and mice, and even controlled small groups of nerve cells in living mice. The techniques, published in two new studies, represent big steps forward for understanding how the brain operates, says molecular neuroscientist Hongkui Zeng of the Allen Institute for Brain Science in Seattle. “Without this kind of technology, we were only able to look at the soup level,” in which diverse nerve cells, or neurons, are grouped and analyzed together, she says. But the new studies show that nerve cells can be studied individually. That zoomed-in approach will begin to uncover the tremendous diversity that’s known to exist among cells, says Zeng, who was not involved in the research. “That is where the field is going. It’s very exciting to see that technologies are now enabling us to do that,” she says. These novel abilities came from multiple tools. At Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Va., physicist Eric Betzig and his colleagues had developed a powerful microscope that can quickly peer deep into layers of brain tissue. Called a lattice light sheet microscope, the rig sweeps a thin sheet of laser light down through the brain, revealing cells’ structures. But like any microscope, it hits a wall when structures get really small, unable to resolve the most minute aspects of the scene. |© Society for Science & the Public 2000 - 2019.

Keyword: Brain imaging
Link ID: 25878 - Posted: 01.18.2019

By Kelly Servick In multiple sclerosis (MS), a disease that strips away the sheaths that insulate nerve cells, the body’s immune cells come to see the nervous system as an enemy. Some drugs try to slow the disease by keeping immune cells in check, or by keeping them away from the brain. But for decades, some researchers have been exploring an alternative: wiping out those immune cells and starting over. The approach, called hematopoietic stem cell transplantation (HSCT), has long been part of certain cancer treatments. A round of chemotherapy knocks out the immune system and an infusion of stem cells—either from a patient’s own blood or, in some cases, that of a donor—rebuilds it. The procedure is already in use for MS and other autoimmune diseases at several clinical centers around the world, but it has serious risks and is far from routine. Now, new results from a randomized clinical trial suggest it can be more effective than some currently approved MS drugs. “A side-by-side comparison of this magnitude had never been done,” says Paolo Muraro, a neurologist at Imperial College London who has also studied HSCT for MS. “It illustrates really the power of this treatment—the level of efficacy—in a way that’s very eloquent.” Nearly 30 years ago, when hematologist Richard Burt saw how HSCT worked in patients with leukemia and lymphoma, he was struck by a curious effect: After those patients rebuilt their immune systems, their childhood vaccines no longer protected them, recalls Burt, now at Northwestern University’s Feinberg School of Medicine in Evanston, Illinois. Without a new vaccination, the new immune cells wouldn’t recognize viruses such as measles and mumps and launch a prompt counterattack. That suggested that in the case of an autoimmune disease, reseeding the immune system might help the body “forget” that its own cells were the enemy. © 2018 American Association for the Advancement of Science

Keyword: Multiple Sclerosis
Link ID: 25870 - Posted: 01.16.2019

Abby Olena In the never-ending search for ways to help people eat healthy, scientists have been looking into brain stimulation, specifically, sending a weak electrical current to the brain through two scalp electrodes—a technique called transcranial direct current stimulation. It has previously shown promise in limiting both food cravings and consumption in people, but in a study published yesterday (January 9) in Royal Society Open Science, researchers didn’t find any effects of tDCS on food-related behavior, indicating that the technique’s use needs another look. “The good things about the study are the large sample size and the fact that it’s fairly rigorous,” says Mark George, a psychiatrist and neurologist at the Medical University of South Carolina who did not participate in the study. “The problem [is] interpreting studies where there’s a failure to find. All you can say is that it didn’t work . . . with this group.” During tDCS, one to two milliamps of electricity—enough to feel tingles or pins and needles, but far less than the 800 or so milliamps used for electroconvulsive therapy—are delivered to the brain. Over the last two decades, scientists have reported targeting the technique to the dorsolateral prefrontal cortex, a brain area that’s been shown to be involved in food-related behavior. They’ve found it has helped people crave less and, to a lesser extent, eat fewer sweets and other tempting foods. Yet these experiments have generally included groups of 20 or fewer people, and other studies have failed to replicate their effects. © 1986 - 2019 The Scientist.

Keyword: Obesity
Link ID: 25861 - Posted: 01.14.2019