Chapter 3. Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
BBC journalist Caroline Wyatt has said she is determined to make the most of her life after being diagnosed with multiple sclerosis (MS). In her first interview since revealing the news last week, Wyatt told the Radio Times: "It is what it is." "I am not angry, and I don't want bitterness to start eating away at me." One of the best known faces of BBC News, Wyatt recently stepped down as the corporation's religious affairs correspondent due to her condition. 'Incredibly blessed' "I feel really sad now because I'm not going to be a correspondent full-time anymore - I physically can't." Wyatt had been struggling with undiagnosed symptoms for 25 years but was only diagnosed with MS last July after she was paralysed down her left side. Wyatt, who was also the BBC's defence correspondent, said she has had moments where she has questioned her own mortality. "Reporting news is often about reporting death, particularly in the places I have been. But it's less terrifying to me to think of being blown up and dying than to think 'gosh, I might decline slowly day by day, losing a little bit of capability every day'." At the moment, she is a bit unsteady on her feet and is struggling with her vision but still says she is "incredibly lucky and incredibly blessed". She is currently on a long summer break but is hoping to return to radio broadcasting later in the year, along with covering the canonisation of Mother Teresa in Rome. In MS the protective layer surrounding nerve fibres in the brain and spinal cord - known as myelin - becomes damaged. The immune system mistakenly attacks the myelin, causing scarring or sclerosis. The damaged myelin disrupts the nerve signals - rather like the short circuit caused by a frayed electrical cable. © 2016 BBC.
Keyword: Multiple Sclerosis
Link ID: 22341 - Posted: 06.21.2016
Aggressive chemotherapy followed by a stem cell transplant can halt the progression of multiple sclerosis (MS), a small study has suggested. The research, published in The Lancet, looked at 24 patients aged between 18 and 50 from three hospitals in Canada. For 23 patients the treatment greatly reduced the onset of the disease, but in one case a person died. An MS Society spokeswoman said this type of treatment does "offer hope" but also comes with "significant risks". Around 100,000 people in the UK have MS, which is an incurable neurological disease. 'No relapses' The condition causes the immune system to attack the lining of nerves in the brain and spinal cord. Most patients are diagnosed in their 20s and 30s. One existing treatment is for the immune system to be suppressed with chemotherapy and then stem cells are introduced to the patient's bloodstream - this procedure is known as an autologous haematopoietic stem cell transplant (HSCT). But in this study, Canadian researchers went further - not just suppressing the immune system, but destroying it altogether. It is then rebuilt with stem cells harvested from the patient's own blood which are at such an early stage, they have not developed the flaws that trigger MS. The authors said that among the survivors, over a period of up to 13 years, there were no relapses and no new detectable disease activity. All the patients who took part in the trial had a "poor prognosis" and had previously undergone standard immunosuppressive therapy which had not controlled the MS - which affects around two million people worldwide. © 2016 BBC.
By Rita Celli, This is what Jennifer Molson remembers doctors saying to her about the high-stakes procedure she would undergo in 2002 as part of an Ottawa study that has yielded some promising results in multiple sclerosis patients. The 41-year-old Ottawa woman was in a wheelchair before the treatment. She now walks, runs and works full time. "I had no feeling from my chest down. I could barely cut my food," Molson remembers. Molson was diagnosed with MS when she was 21, and within five years she needed full-time care. "It was scary. [The procedure] was my last shot at living." MS is among the most common chronic inflammatory diseases of the central nervous system, affecting an estimated two million people worldwide. New Canadian research led by two Ottawa doctors and published in The Lancet medical journal on Thursday suggests the high-risk therapy may stop the disease from progressing. "This is the first treatment to produce this level of disease control or neurological recovery" from MS, said The Lancet in a news release. But The Lancet also highlights the high mortality rate associated with the procedure — one patient out of 24 involved in the clinical trial died from liver failure. "Treatment related risks limit [the therapy's] widespread use," The Lancet concludes. Results 'impressive' Nevertheless, in the journal's accompanying editorial a German doctor calls the results "impressive." ©2016 CBC/Radio-Canada.
By JAMES GORMAN This summer’s science horror blockbuster is a remake: Return of the Leaping Electric Eel! If you have any kind of phobia of slimy, snakelike creatures that can rise from the water and use their bodies like Tasers, this story — and the accompanying video — may not be for you. The original tale (there was, alas, no video) dates to 1800 when the great explorer Alexander von Humboldt was in South America and enlisted local fishermen to catch some of these eels for the new (at the time) study of electricity. He wrote that the men herded horses and mules into a shallow pond and let the eels attack by pressing themselves against the horses. The horses and mules tried to escape, but the fishermen kept them in the water until the eels used up their power. Two horses died, probably from falling and drowning. Or so Humboldt said. Though the story was widely retold, no other report of this kind of fishing-with-horses phenomenon surfaced for more than 200 years, according to Kenneth Catania, a scientist with a passion for studying the eel species in question, electrophorus electricus. In 2014, he reported on how the eels freeze their prey. They use rapid pulses of more than 600 volts generated by modified muscle cells and sent through the water. These volleys of shocks cause the muscles of prey to tense at once, stopping all movement. The eels’ bodies function like Tasers, Dr. Catania wrote. But they can also project high-voltage pulses in the water in isolated couplets rather than full volleys for a different effect. The pairs of shocks don’t freeze the prey, but cause their bodies to twitch. That movement reveals the prey’s location, and then the eels send out a rapid volley to immobilize then swallow it. Dr. Catania noticed another kind of behavior, however. He was using a metal-handled net — wearing rubber gloves — while working with eels in an aquarium, and the eels would fling themselves up the handle of the net, pressing themselves to the metal and generating rapid electric shocks. © 2016 The New York Times Company
James Gorman Fruit flies are far from human, but not as far as you might think. They do many of the same things people do, like seek food, fight and woo mates. And their brains, although tiny and not set up like those of humans or other mammals, do many of the same things that all brains do — make and use memories, integrate information from the senses, and allow the creature to navigate both the physical and the social world. Consequently, scientists who study how all brains work like to use flies because it’s easier for them to do invasive research that isn’t allowed on humans. The technology of neuroscience is sophisticated enough to genetically engineer fly brains, and to then use fluorescent chemicals to indicate which neurons are active. But there are some remaining problems, like how to watch the brain of a fly that is moving around freely. It is one thing to record what is going on in a fly’s brain if the insect’s movement is restricted, but quite another to try to catch the light flash of brain cells from a fly that is walking around. Takeo Katsuki, an assistant project scientist at the Kavli Institute at the University of California, San Diego, is interested in courtship. And, he said, fruit flies simply won’t engage in courtship when they are tethered. So he and Dhruv Grover, another assistant project scientist, and Ralph J. Greenspan, in whose lab they both work, set out to develop a method for recording the brain activity of a walking fly. One challenge was to track the fly as it moved. They solved that problem with three cameras to follow the fly and a laser to activate the fluorescent chemicals in the brain. © 2016 The New York Times Company
Scientists say they have found a gene that causes a rare but inherited form of multiple sclerosis. It affects about one in every thousand MS patients and, according to the Canadian researchers, is proof that the disease is passed down generations. Experts have long suspected there's a genetic element to MS, but had thought there would be lots of genes involved, as well as environmental factors. The finding offers hope of targeted screening and therapy, Neuron reports. The University of British Columbia studied the DNA of hundreds of families affected by MS to hunt for a culprit gene. They found it in two sets of families containing several members with a rapidly progressive type of MS. In these families, 70% of the people with the mutation developed the disease. Although other factors may still be important and necessary to trigger the disease process, the gene itself is a substantial causative risk factor that is passed down from parents to their children, say the researchers. The mutation is in a gene called NR1H3, which makes a protein that acts as a switch controlling inflammation. In MS the body's immune system mistakenly attacks the protective layer of myelin that surrounds nerve fibres in the brain and spinal cord, leading to muscle weakness and other symptoms. Studies in mice show that knocking out the function of the same gene leads to neurological problems and decreased myelin production. © 2016 BBC.
By Frances Marcellin A shirt and cap that can diagnose epilepsy quickly and easily has been approved for use by European health services, including the UK’s NHS. Epileptic seizures are the result of excessive electrical discharges in the brain. The World Health Organization estimates that over 50 million people worldwide have the condition, including 6 million in Europe, making it one of the world’s most common serious neurological conditions. Brain implants and apps have been developed to warn of oncoming seizures. But to diagnose the condition, someone must typically have a seizure recorded by an EEG machine in a hospital – with sensors and wires attached to the scalp. “An EEG reading is at the heart of a reliable diagnosis,” says Françoise Thomas-Vialettes, president of French epilepsy society EFAPPE. But seizures rarely coincide with hospital appointments. “The diagnosis can take several years and is often imprecise.” Seizures are so difficult to record that 30 per cent of people with epilepsy in Europe are misdiagnosed. In developing countries that lack medical equipment and healthcare the situation is even worse. To make diagnosis easier, French start-up BioSerenity has developed a smart outfit called the Neuronaute that monitors people as they go about their day. The shirt and cap are embedded with biometric sensors that record the electrical activity of the wearer’s brain, heart and muscles. If a seizure occurs, the outfit can send an EEG recording of the brain to doctors via a smartphone. © Copyright Reed Business Information Ltd.
Link ID: 22271 - Posted: 06.01.2016
Sara Reardon Every time something poked its foot, the mouse jumped in pain. Researchers at Circuit Therapeutics, a start-up company in Menlo Park, California, had made the animal hypersensitive to touch by tying off a nerve in its leg. But when they shone a yellow light on its foot while poking it, the mouse did not react. The treatment is one of several nearing clinical use that draw on optogenetics — a technique in which light is used to control genes and neuron firing. In March, RetroSense Therapeutics of Ann Arbor, Michigan, began the first clinical-safety trial of an optogenetic therapy to treat the vision disorder retinitis pigmentosa. Many scientists are waiting to see how the trial turns out before they decide how to move forward with their own research on a number of different applications. “I think it will embolden people if there’s good news,” says Robert Gereau, a pain researcher at Washington University in St Louis, Missouri. “It opens up a whole new range of possiblilities for how to treat neurological diseases.” Retinitis pigmentosa destroys photoreceptors in the eye. RetroSense’s treatment seeks to compensate for this loss by conferring light sensitivity to retinal ganglion cells, which normally help to pass visual signals from photoreceptors to the brain. The therapy involves injecting patients who are blind or mostly blind with viruses carrying genes that encode light-sensitive proteins called opsins. The cells fire when stimulated with blue light, passing the visual information to the brain. Chief executive Sean Ainsworth says that the company has injected several individuals in the United States with the treatment, and plans to enroll a total of 15 blind patients in its trial. RetroSense will follow them for two years, but may release some preliminary data later this year. © 2016 Nature Publishing Group
Link ID: 22235 - Posted: 05.21.2016
Bret Stetka Last year, in an operating room at the University of Toronto, a 63-year-old women with Alzheimer's disease experienced something she hadn't for 55 years: a memory of her 8-year-old self playing with her siblings on their family farm in Scotland. The woman is a patient of Dr. Andres Lozano, a neurosurgeon who is among a growing number of researchers studying the potential of deep brain stimulation to treat Alzheimer's and other forms of dementia. If the approach pans out it could provide options for patients with fading cognition and retrieve vanished memories. Right now, deep brain stimulation is used primarily to treat Parkinson's disease and tremor, for which it's approve by the Food and Drug Administration. DBS involves delivering electrical impulses to specific areas of the brain through implanted electrodes. The technique is also approved for obsessive-compulsive disorder and is being looked at for a number of other brain disorders, including depression, chronic pain and, as in Lozano's work, dementia. In 2008 Lozano's group published a study in which an obese patient was treated with deep brain stimulation of the hypothalamus. Though no bigger than a pea, the hypothalamus is a crucial bit of brain involved in appetite regulation and other bodily essentials such as temperature control, sleep and circadian rhythms. It seemed like a reasonable target in trying to suppress excessive hunger. To the researcher's surprise, following stimulation the patient reported a sensation of deja vu. He also perceived feeling 20 years younger and recalled a memory of being in a park with friends, including an old girlfriend. With increasing voltages his memories became more vivid. He remembered their clothes. © 2016 npr
Keyword: Learning & Memory
Link ID: 22213 - Posted: 05.14.2016
By John Elder Robison Manipulating your brain with magnetic fields sounds like science fiction. But the technique is real, and it’s here. Called transcranial magnetic stimulation (TMS), it is approved as a therapy for depression in the US and UK. More controversially, it is being studied as a way to treat classic symptoms of autism, such as emotional disconnection. With interest and hopes rising, it’s under the spotlight at the International Meeting for Autism Research in Baltimore, Maryland, next week. I can bear witness to the power of TMS, which induces small electrical currents in neurons. As someone with Asperger’s, I tried it for medical research, and described its impact in my book Switched On. After TMS, I could see emotional cues in other people – signals I had always been blind to, but that many non-autistic people pick up with ease. That sounds great, so why the need for debate? Relieving depression isn’t controversial, because there is no question people suffer as a result of it. I too felt that I suffered – from emotional disconnection. But changing “emotional intelligence” to relieve that comes closer to changing the essence of how we think. Yes, emerging brain therapies like TMS have great potential. Several of the volunteers who went into the TMS lab at Harvard Medical School emerged with new self-awareness, and lasting changes. While I can’t speak with certainty for the others, I believe some of us have a degree of emotional insight that we didn’t have before. I certainly feel better able to fit in. As fellow participant Michael Wilcox put it, we have more emotional reactions to things we see or read. © Copyright Reed Business Information Ltd.
Link ID: 22187 - Posted: 05.07.2016
By Jennifer Jolly Every January for the past decade, Jessica Irish of Saline, Mich., has made the same New Year’s Resolution: to “cut out late night snacking and lose 30 pounds.” Like millions of Americans, Ms. Irish, 31, usually makes it about two weeks. But this year is different. “I’ve already lost 18 pounds,” she said, “and maintained my diet more consistently than ever. Even more amazing — I rarely even think about snacking at night anymore.” Ms. Irish credits a new wearable device called Pavlok for doing what years of diets, weight-loss programs, expensive gyms and her own willpower could not. Whenever she takes a bite of the foods she wants to avoid, like chocolate or Cheez-Its, she uses the Pavlok to give herself a lightning-quick electric shock. “Every time I took a bite, I zapped myself,” she said. “I did it five times on the first night, two times on the second night, and by the third day I didn’t have any cravings anymore.” As the name suggests, the $199 Pavlok, worn on the wrist, uses the classic theory of Pavlovian conditioning to create a negative association with a specific action. Next time you smoke, bite your nails or eat junk food, one tap of the device or a smartphone app will deliver a shock. The zap lasts only a fraction of a second, though the severity of the shock is up to you. It can be set between 50 volts, which feels like a strong vibration, and 450 volts, which feels like getting stung by a bee with a stinger the size of an ice pick. (By comparison, a police Taser typically releases about 50,000 volts.) Other gadgets and apps dabble in behavioral change by way of aversion therapy, such as the $49 MotivAider that is worn like a pager, or the $99 RE-vibe wristband. Both can be set to vibrate at specific intervals as a reminder of a habit to break or a goal to reach. The $80 Lumo Lift posture coach is a wearable disk that vibrates when you slouch. The $150 Spire clip-on sensor tracks physical activity and state of mind by detecting users’ breathing patterns. If it detects you’re stressed or anxious, it vibrates or sends a notification to your smartphone to take a deep breath. © 2016 The New York Times Company
Keyword: Learning & Memory
Link ID: 22171 - Posted: 05.03.2016
By Julia Shaw In the last couple of years memory science has really upped its game. I generally write about social processes that can change our memories, but right now I can’t help but get excited that memory science is getting an incredible new toy to play with. A toy that I believe will revolutionise how we talk about, and deal with, memory. This not-so-new sounding, but totally-newly-applied, neuroscience toy is ultrasound. Ultrasound is also called sonography and is essentially a type of ‘medical sonar’. It has revolutionized medicine since the 1940s, giving us the ability to look into the body in a completely safe way (without leaving icky radiation behind, like xrays). Beyond predicting whether your baby shower will be blue or pink, lesser known applications of ultrasound include the ability to essentially burn and destroy cells inside your body. As such, it has been successfully used to do surgery without making any cuts into the human body. This is a technique that has been used to remove cancerous cells while not affecting any of the surrounding tissue, and without any of the side-effects associated with other kinds of cancer treatment. This is referred to by scientist Yoav Medan as focused ultrasound. If you are unfamiliar with this, you need to watch this TED talk. Non-invasive procedures like this are the future of surgery. Non-invasive procedures are also the future of neuroscience. It is at this point that we find ourselves at the application of this astonishing science to memory research. © 2016 Scientific American
By Emily Underwood Earlier this month, György Buzsáki of New York University (NYU) in New York City showed a slide that sent a murmur through an audience in the Grand Ballroom of New York’s Midtown Hilton during the annual meeting of the Cognitive Neuroscience Society. It wasn’t just the grisly image of a human cadaver with more than 200 electrodes inserted into its brain that set people whispering; it was what those electrodes detected—or rather, what they failed to detect. When Buzsáki and his colleague, Antal Berényi, of the University of Szeged in Hungary, mimicked an increasingly popular form of brain stimulation by applying alternating electrical current to the outside of the cadaver’s skull, the electrodes inside registered little. Hardly any current entered the brain. On closer study, the pair discovered that up to 90% of the current had been redirected by the skin covering the skull, which acted as a “shunt,” Buzsáki said. For many meeting attendees, the unusual study heightened serious doubts about the mechanism and effectiveness of transcranial direct current stimulation (tDCS), an experimental, noninvasive treatment that uses electrodes to deliver weak current to a person’s forehead, and the related tACS, which uses alternating current. Little is known about how these techniques might influence the brain. Yet many scientific papers have claimed that the techniques can boost mood, alleviate chronic pain, and even make people better at math by directly affecting neuronal activity. This has spawned a cottage industry of do-it-yourself gadgets promising to make people smarter and happier. © 2016 American Association for the Advancement of Science
Link ID: 22126 - Posted: 04.21.2016
Helen Shen Clamping an electrode to the brain cell of a living animal to record its electrical chatter is a task that demands finesse and patience. Known as ‘whole-cell patch-clamping’, it is reputedly the “finest art in neuroscience”, says neurobiologist Edward Boyden, and one that only a few dozen laboratories around the world specialize in. But researchers are trying to demystify this art by turning it into a streamlined, automated technique that any laboratory could attempt, using robotics and downloadable source code. “Patch-clamping provides a unique view into neural circuits, and it’s a very exciting technique but is really underused,” says neuroscientist Karel Svoboda at the Howard Hughes Medical Institute’s Janelia Research Campus in Ashburn, Virginia. “That’s why automation is a really, really exciting direction.” On 3 March, Boyden, at the Massachusetts Institute of Technology in Cambridge, and his colleagues published detailed instructions on how to assemble and operate an automated system for whole-cell patch-clamping1, a concept that they first described in 20122. The guide represents the latest fruits of Boyden’s partnership with the laboratory of Craig Forest, a mechanical engineer at the Georgia Institute of Technology in Atlanta who specializes in robotic automation for research. © 2016 Nature Publishing Group
Keyword: Brain imaging
Link ID: 22066 - Posted: 04.04.2016
By Ariana Eunjung Cha LAS VEGAS — Jamie Tyler was stressed. He had just endured a half-hour slog through airport security and needed some relief. Many travelers in this situation might have headed for the nearest bar or popped an aspirin. But Tyler grabbed a triangular piece of gadgetry from his bag and held it to his forehead. As he closed his eyes, the device zapped him with low-voltage electrical currents. Within minutes, Tyler said, he was feeling serene enough to face the crowds once again. This is no science fiction. The Harvard-trained neurobiologist was taking advantage of one of his own inventions, a device called Thync, which promises to help users activate their body's “natural state of energy or calm” — for a retail price of a mere $199. Americans’ obsession with wellness is fueling a new category of consumer electronics, one that goes far beyond the ubiquitous Fitbits and UP activity wristbands that only passively monitor users' physical activity. The latest wearable tech, to put it in the simplest terms, is about hacking your brain. These gadgets claim to be able to make you have more willpower, think more creatively and even jump higher. One day, their makers say, the technology may even succeed in delivering on the holy grail of emotions: happiness. There’s real, peer-reviewed science behind the theory driving these devices. It involves stimulating key regions of the brain — with currents or magnetic fields — to affect emotions and physical well-being.
Link ID: 22053 - Posted: 03.31.2016
We might finally be figuring out how an increasingly popular therapy that uses electricity to boost the brain’s functioning has its effects – by pushing up levels of calcium in cells. Transcranial direct current stimulation (tDCS) involves using electrodes to send a weak current across the brain. Stimulating brain tissue like this has been linked to effects ranging from accelerating learning to improving the symptoms of depression and faster recovery from strokes. The broad consensus is that tDCS does this by lowering the threshold at which neurons fire, making it easier for them to pass on electrical signals. This leads to changes in the connectivity between neurons and alters information processing. But the cellular mechanisms that lead to such broad neurological changes are not clear and some researchers suggest that tDCS may not have any effect on the brain. Despite the doubts, devices are being developed for sale to people keen to influence their own brains. Now Hajime Hirase at the RIKEN Brain Science Institute in Tokyo, Japan, and his colleagues may have found an answer. They have identified large, sudden surges in calcium flow in the brains of mice seconds after they receive low doses of tDCS. These surges seem to start in cells called astrocytes – star-shaped cells that don’t fire themselves, but help to strengthen the connections between neurons and regulate the electrical signals that pass between them. © Copyright Reed Business Information Ltd.
Mo Costandi Researchers in the United States have developed a new method for controlling the brain circuits associated with complex animal behaviours, using genetic engineering to create a magnetised protein that activates specific groups of nerve cells from a distance. Understanding how the brain generates behaviour is one of the ultimate goals of neuroscience – and one of its most difficult questions. In recent years, researchers have developed a number of methods that enable them to remotely control specified groups of neurons and to probe the workings of neuronal circuits. The most powerful of these is a method called optogenetics, which enables researchers to switch populations of related neurons on or off on a millisecond-by-millisecond timescale with pulses of laser light. Another recently developed method, called chemogenetics, uses engineered proteins that are activated by designer drugs and can be targeted to specific cell types. Although powerful, both of these methods have drawbacks. Optogenetics is invasive, requiring insertion of optical fibres that deliver the light pulses into the brain and, furthermore, the extent to which the light penetrates the dense brain tissue is severely limited. Chemogenetic approaches overcome both of these limitations, but typically induce biochemical reactions that take several seconds to activate nerve cells. The new technique, developed in Ali Güler’s lab at the University of Virginia in Charlottesville, and described in an advance online publication in the journal Nature Neuroscience, is not only non-invasive, but can also activate neurons rapidly and reversibly. © 2016 Guardian News and Media Limited
Keyword: Brain imaging
Link ID: 22034 - Posted: 03.26.2016
By ANDREW POLLACK An experimental drug derived from marijuana has succeeded in reducing epileptic seizures in its first major clinical trial, the product’s developer announced on Monday, a finding that could lend credence to the medical marijuana movement. The developer, GW Pharmaceuticals, said the drug, Epidiolex, achieved the main goal of the trial, reducing convulsive seizures when compared with a placebo in patients with Dravet syndrome, a rare form of epilepsy. GW shares more than doubled on Monday. If Epidiolex wins regulatory approval, it would be the first prescription drug in the United States that is extracted from marijuana. The drug is a liquid containing cannabidiol, a component of marijuana that does not make people high. As many as 30 percent of the nearly 500,000 American children with epilepsy are not sufficiently helped by existing drugs, according to GW. Parents of some of these children have been flocking to try marijuana extracts, prepared by medical marijuana dispensaries. A number of states, in response to pressure from these parents, have passed or considered legislation to make it easier to obtain marijuana-based products. And some families have become “marijuana refugees,” moving to Colorado where it has been easier to obtain a particular extract, known as Charlotte’s Web, after the girl who first used it to control seizures. Hundreds of other children and young adults have been using Epidiolex outside of clinical trials, under programs that allow desperate patients to use experimental drugs. While many parents have reported significant reductions in seizures, experts have been cautious about anecdotal reports, saying that such treatments needed to be compared with a placebo to make sure they work. As such, the results from the GW trial have been closely watched. © 2016 The New York Times Company
By Sandra G. Boodman Kim Pace was afraid he was dying. In six months he had lost more than 30 pounds because a terrible stabbing sensation on the left side of his face made eating or drinking too painful. Brushing his teeth was out of the question and even the slightest touch triggered waves of agony and a shocklike pain he imagined was comparable to electrocution. Painkillers, even morphine, brought little relief. Unable to work and on medical leave from his job as a financial consultant for a bank, Pace, then 59, had spent the first half of 2012 bouncing among specialists in his home state of Pennsylvania, searching for help from doctors who disagreed about the nature of his illness. Some thought his searing pain might be the side effect of a drug he was taking. Others suspected migraines, a dental problem, mental illness, or an attempt to obtain painkillers. Even after a junior doctor made what turned out to be the correct diagnosis, there was disagreement among specialists about its accuracy or how to treat Pace. His wife, Carol, a nurse, said she suspects that the couple’s persistence and propensity to ask questions led her husband to be branded “a difficult case” — the kind of patient whom some doctors avoid. And on top of that, a serious but entirely unrelated disorder further muddied the diagnostic picture. So on July 17, 2012, when Pace told his wife he thought he was dying, she fired off an emotional plea for help to the office of a prominent specialist in Baltimore. “I looked at Kim and it hit me: He was going to die,” she said. “He was losing weight and his color was ashen” and doctors were “blowing him off. I thought, ‘Okay, that’s it,’ and the nurse in me took over.”
By Simon Makin Brain implants have been around for decades—stimulating motor areas to alleviate Parkinson's disease symptoms, for example—but until now they have all suffered from the same limitation: because brains move slightly during physical activity and as we breathe and our heart beats, rigid implants rub and damage tissue. This means that eventually, because of both movement and scar-tissue formation, they lose contact with the cells they were monitoring. Now a group of researchers, led by chemist Charles Lieber of Harvard University, has overcome these problems using a fine, flexible mesh. In 2012 the team showed that cells could be grown around such a mesh, but that left the problem of how to get one inside a living brain. The solution the scientists devised was to draw the mesh—measuring a few millimeters wide—into a syringe, so it would roll up like a scroll inside the 100-micron-wide needle, and inject it through a hole in the skull. In a study published in Nature Nanotechnology last year, the team injected meshes studded with 16 electrodes into two brain regions in mice. The mesh is composed of extremely thin, nanoscale polymer threads, sparsely distributed so that 95 percent of it is empty space. It has a level of flexibility similar to brain tissue. “You're starting to make this nonliving system look like the biological system you're trying to probe,” Lieber explains. “That's been the goal of my group's work, to blur the distinction between electronics as we know it and the computer inside our heads.” © 2016 Scientific American
Keyword: Brain imaging
Link ID: 21950 - Posted: 03.03.2016