By Michelle Roberts Health editor, BBC News online The brain has a weak spot for Alzheimer's disease and schizophrenia, according to UK scientists who have pinpointed the region using scans. The brain area involved develops late in adolescence and degenerates early during ageing. At the moment, it is difficult for doctors to predict which people might develop either condition. The findings, in the journal PNAS, hint at a potential way to diagnose those at risk earlier, experts say. Although they caution that "much more research is needed into how to bring these exciting discoveries into the clinic". The Medical Research Council team who carried out the study did MRI brain scans on 484 healthy volunteers aged between eight and 85 years. The researchers, led by Dr Gwenaëlle Douaud of Oxford University, looked at how the brain naturally changes as people age. The images revealed a common pattern - the parts of the brain that were the last to develop were also the first to show signs of age-related decline. These brain regions - a network of nerve cells or grey matter - co-ordinate "high order" information coming from the different senses, such as sight and sound. When the researchers looked at scans of patients with Alzheimer's disease and scans of patients with schizophrenia they found the same brain regions were affected. The findings fit with what other experts have suspected - that although distinct, Alzheimer's and schizophrenia are linked. Prof Hugh Perry of the MRC said: "Early doctors called schizophrenia 'premature dementia' but until now we had no clear evidence that the same parts of the brain might be associated with two such different diseases. This large-scale and detailed study provides an important, and previously missing, link between development, ageing and disease processes in the brain. BBC © 2014

Keyword: Alzheimers; Schizophrenia
Link ID: 20354 - Posted: 11.25.2014

By Sandra G. Boodman ‘That’s it — I’m done,” Rachel Miller proclaimed, the sting of the neurologist’s judgment fresh as she recounted the just-concluded appointment to her husband. Whatever was wrong with her, Miller decided after that 2009 encounter, she was not willing to risk additional humiliation by seeing another doctor who might dismiss her problems as psychosomatic. The Baltimore marketing executive had spent the previous two years trying to figure out what was causing her bizarre symptoms, some of which she knew made her sound delusional. Her eyes felt “weird,” although her vision was 20/20. Normal sounds seemed hugely amplified: at night when she lay in bed, her breathing and heartbeat were deafening. Water pounding on her back in the shower sounded like a roar. She was plagued by dizziness. “I had started to feel like a person in one of those stories where someone has been committed to a mental hospital by mistake or malice and they desperately try to appear sane,” recalled Miller, now 53. She began to wonder if she really was crazy; numerous tests had ruled out a host of possible causes, including a brain tumor. Continuing to look for answers seemed futile, since all the doctors she had seen had failed to come up with anything conclusive. “My attitude was: If it’s something progressive like MS [multiple sclerosis] or ALS [amyotrophic lateral sclerosis], it’ll get bad enough that someone will eventually figure it out.” Figuring it out would take nearly three more years and was partly the result of an oddity that Miller mentioned to another neurologist, after she lifted her moratorium on seeing doctors.

Keyword: Hearing
Link ID: 20353 - Posted: 11.25.2014

By Chelsea Rice On December 14, 2012, Adam Lanza shot and killed 20 children and six personnel at Sandy Hook Elementary School in Newtown, Connecticut, before turning the gun on himself. Ever since, America has been wondering: Why? Today, after investigating and detailing every available record of the 20-year-old Lanza’s life since birth, the Connecticut Office of the Child Advocate released a report that said: We still don’t know what drove him to commit those terrible acts. But we do know he fell through the cracks of the school system, the health care system, and possibly the awareness of his own parents. Every documented moment of Lanza’s life was evaluated, from mental health records that tracked his social development to school and medical records that outlined his needs—and showed disparities in the services provided to him by the state. The review did not, however, stop at Lanza. It included a review of the laws regarding special education and the confidentiality of personal records in the system, as well as “how these laws implicate professional obligations and practices.” Unredacted state police and law enforcement records were also reviewed alongside interviews and extensive research with members of the Child Fatality Review Panel who led the initial investigation of that day. From “earliest childhood,” according to the report, Lanza had “significant developmental challenges,” such as communication and sensory problems, delays in socialization, and repetitive behaviors. Lanza was seen and evaluated by the New Hampshire “Birth to Three” early intervention program when he was almost 3 years old, and referred to special education preschool services.

Keyword: Autism; Aggression
Link ID: 20352 - Posted: 11.25.2014

By Victoria Colliver Marianne Austin watched her mother go blind from age-related macular degeneration, an eye disease that affects about 10 million older Americans. Now that Austin has been diagnosed with the same condition, she wants to avoid her mother’s experience. “I’ve seen what can happen and the devastation it can cause,” said Austin, 67, of Atherton, who found out she had the disease last year. “I call it having seen the movie. I don’t like that ending, I want to change the movie, and I don’t want to wait 10 years until something is proven in research.” About 10 percent of patients diagnosed with age-related macular degeneration will develop the form of the disease that causes permanent blindness. It’s unclear just how much genetics plays a role, so there’s no definitive way to predict who will progress to that stage or when that would happen. But a team of Stanford doctors think they may have found a way. In a study, published this month in the medical journal Investigative Ophthalmology and Visual Science, researchers analyzed data from 2,146 retinal scans from 244 macular degeneration patients at Stanford from 2008 to 2013. They then created an algorithm that predicted whether a particular patient would be likely to develop the form of the disease that causes blindness within less than a year, three years or up to five years. For those with macular degeneration to go blind, the disease has to advance from what is known as the “dry” form to the “wet” form. The sooner a doctor can notice changes, the better chance there is to save a patient’s vision.

Keyword: Vision; Development of the Brain
Link ID: 20351 - Posted: 11.25.2014

|By Christof Koch Point to any one organ in the body, and doctors can tell you something about what it does and what happens if that organ is injured by accident or disease or is removed by surgery—whether it be the pituitary gland, the kidney or the inner ear. Yet like the blank spots on maps of Central Africa from the mid-19th century, there are structures whose functions remain unknown despite whole-brain imaging, electroencephalographic recordings that monitor the brain's cacophony of electrical signals and other advanced tools of the 21st century. Consider the claustrum. It is a thin, irregular sheet of cells, tucked below the neocortex, the gray matter that allows us to see, hear, reason, think and remember. It is surrounded on all sides by white matter—the tracts, or wire bundles, that interconnect cortical regions with one another and with other brain regions. The claustra—for there are two of them, one on the left side of the brain and one on the right—lie below the general region of the insular cortex, underneath the temples, just above the ears. They assume a long, thin wisp of a shape that is easily overlooked when inspecting the topography of a brain image. Advanced brain-imaging techniques that look at the white matter fibers coursing to and from the claustrum reveal that it is a neural Grand Central Station. Almost every region of the cortex sends fibers to the claustrum. These connections are reciprocated by other fibers that extend back from the claustrum to the originating cortical region. Neuroanatomical studies in mice and rats reveal a unique asymmetry—each claustrum receives input from both cortical hemispheres but only projects back to the overlying cortex on the same side. Whether or not this is true in people is not known. Curiouser and curiouser, as Alice would have said. © 2014 Scientific American

Keyword: Consciousness
Link ID: 20350 - Posted: 11.24.2014

By Amy Ellis Nutt Debbie Hall undergoes external brain stimulation at Ohio State's Wexner Medical Center. Hall was partially paralyzed on her left side after a stroke. Doctors are conducting a study to see if a device known as NexStim can `prep` a stroke victim's brain immediately prior to physical therapy so that the therapy will be more effective. (The Ohio State University Wexner Medical Center) Using non-invasive transcranial magnetic stimulation, or TMS, researchers at Ohio State Wexner Medical Center may have found a way to help prep a stroke victim's brain prior to physical therapy to aid a more complete recovery. When one side of the brain is damaged by a stroke, the corresponding healthy part goes into overdrive in order to compensate, said Dr. Marcie Bockbrader, principle investigator of the study. She believes the hyperactivity in the healthy side may actually slow recovery in the injured side. The technology, called NexStim, employs TMS to prepare a stroke patient's brain for physical therapy by sending low-frequency magnetic pulses painlessly through a victim's scalp to suppress activity in the healthy part of the motor cortex. This allows the injured side to make use of more energy during physical therapy, which immediately follows the transcranial magnetic stimulation. "This device targets the overactive side, quieting it down enough, so that through therapies the injured side can learn to express itself again," said Bockbrader, an assistant professor of physical medicine and rehabilitation, in a new release.

Keyword: Stroke
Link ID: 20349 - Posted: 11.24.2014

by Hal Hodson Yet another smartwatch launched this week. Called Embrace, it is rather different from the latest offerings from Apple, Samsung and Motorola: it can spot the warning signs of an epileptic seizure. Embrace was developed by Matteo Lai and his team at a firm called Empatica, with the help of Rosalind Picard at the Massachusetts Institute of Technology. It measures the skin's electrical activity as a proxy for changes deep in the brain, and uses a model built on years of clinical data to tell which changes portend a seizure. It also gathers the usual temperature and motion data that smartwatches collect, allowing the wearer to measure physical activity and sleep quality. Empatica launched a crowdfunding campaign on Indiegogo on Tuesday and has already raised more than $120,000. Backers who pledge $169 will receive an Embrace watch. The idea for the wristband came when Picard and her colleagues were running a study on the emotional states of children with autism, measuring skin conductance at the wrist as part of the study. Picard noticed that one of the children had registered a spike in electrical activity that turned out to have happened 20 minutes before they noticed the symptoms of a seizure. "It shocked me when I realised these things were showing up on the wrist," says Picard. The whole point of Embrace is to prevent sudden unexplained death in epilepsy (SUDEP). Its causes are not fully understood, but Picard says they understand enough to know how to reduce the chances of dying after an epileptic seizure. © Copyright Reed Business Information Ltd.

Keyword: Epilepsy; Robotics
Link ID: 20348 - Posted: 11.24.2014

Kate Szell “I once asked Clara who she was. It was so embarrassing, but she’d had a haircut, so how was I to know?” That’s Rachel, she’s 14 and counts Clara as one of her oldest and best friends. There’s nothing wrong with Rachel’s sight, yet she struggles to recognise others. Why? Rachel is face blind. Most of us take for granted the fact that we recognise someone after a quick glance at their face. We don’t realise we’re doing something very different when we look at a face compared with when we look at anything else. To get a feeling of how peculiar facial recognition is, try recognising people by looking at their hands, instead of their faces. Tricky? That’s exactly how Rachel feels – only she’s not looking at hands, she’s looking straight into someone’s eyes. Specific areas of the brain process facial information. Damage to those areas gives rise to prosopagnosia or “face blindness”: an inability or difficulty with recognising faces. While brain damage-induced prosopagnosia is rare, prosopagnosia itself is not. Studies suggest around 2% of the population could have some form of prosopagnosia. These “developmental” prosopagnosics seem to be born without the ability to recognise faces and don’t acquire it, relying instead on all manner of cues, from gait to hairstyles, to tell people apart. Kirsten Dalrymple from the University of Minnesota is one of a handful of researchers looking into developmental prosopagnosia. Her particular interest is in prosopagnosic children. “Some seem to cope without much of a problem but, for others, it’s a totally different story,” she says. “They can become very socially withdrawn and can also be at risk of walking off with strangers.” © 2014 Guardian News and Media Limited o

Keyword: Attention
Link ID: 20347 - Posted: 11.24.2014

By CLYDE HABERMAN The notion that a person might embody several personalities, each of them distinct, is hardly new. The ancient Romans had a sense of this and came up with Janus, a two-faced god. In the 1880s, Robert Louis Stevenson wrote “Strange Case of Dr. Jekyll and Mr. Hyde,” a novella that provided us with an enduring metaphor for good and evil corporeally bound. Modern comic books are awash in divided personalities like the Hulk and Two-Face in the Batman series. Even heroic Superman has his alternating personas. But few instances of the phenomenon captured Americans’ collective imagination quite like “Sybil,” the study of a woman said to have had not two, not three (like the troubled figure in the 1950s’ “Three Faces of Eve”), but 16 different personalities. Alters, psychiatrists call them, short for alternates. As a mass-market book published in 1973, “Sybil” sold in the millions. Tens of millions watched a 1976 television movie version. The story had enough juice left in it for still another television film in 2007. Sybil Dorsett, a pseudonym, became the paradigm of a psychiatric diagnosis once known as multiple personality disorder. These days, it goes by a more anodyne label: dissociative identity disorder. Either way, the strange case of the woman whose real name was Shirley Ardell Mason made itself felt in psychiatrists’ offices across the country. Pre-"Sybil,” the diagnosis was rare, with only about 100 cases ever having been reported in medical journals. Less than a decade after “Sybil” made its appearance, in 1980, the American Psychiatric Association formally recognized the disorder, and the numbers soared into the thousands. People went on television to tell the likes of Jerry Springer and Leeza Gibbons about their many alters. One woman insisted that she had more than 300 identities within her (enough, if you will, to fill the rosters of a dozen major-league baseball teams). Even “Eve,” whose real name is Chris Costner Sizemore, said in the mid-1970s that those famous three faces were surely an undercount. It was more like 22, she said. © 2014 The New York Times Company

Keyword: Consciousness
Link ID: 20346 - Posted: 11.24.2014

Christopher Stringer Indeed, skeletal evidence from every inhabited continent suggests that our brains have become smaller in the past 10,000 to 20,000 years. How can we account for this seemingly scary statistic? Some of the shrinkage is very likely related to the decline in humans' average body size during the past 10,000 years. Brain size is scaled to body size because a larger body requires a larger nervous system to service it. As bodies became smaller, so did brains. A smaller body also suggests a smaller pelvic size in females, so selection would have favored the delivery of smaller-headed babies. What explains our shrinking body size, though? This decline is possibly related to warmer conditions on the earth in the 10,000 years after the last ice age ended. Colder conditions favor bulkier bodies because they conserve heat better. As we have acclimated to warmer temperatures, the way we live has also generally become less physically demanding, which overall serves to drive down body weights. Another likely reason for this decline is that brains are energetically expensive and will not be maintained at larger sizes unless it is necessary. The fact that we increasingly store and process information externally—in books, computers and online—means that many of us can probably get by with smaller brains. Some anthropologists have also proposed that larger brains may be less efficient at certain tasks, such as rapid computation, because of longer connection pathways. © 2014 Scientific American

Keyword: Evolution
Link ID: 20345 - Posted: 11.24.2014

by Linda Geddes A tapeworm that usually infects dogs, frogs and cats has made its home inside a man's brain. Sequencing its genome showed that it contains around 10 times more DNA than any other tapeworm sequenced so far, which could explain its ability to invade many different species. When a 50-year-old Chinese man was admitted to a UK hospital complaining of headaches, seizures, an altered sense of smell and memory flashbacks, his doctors were stumped. Tests for tuberculosis, syphilis, HIV and Lyme disease were negative, and although an MRI scan showed an abnormal region in the right side of his brain, a biopsy found inflammation, but no tumour. Over the next four years, further MRIs recorded the abnormal region moving across the man's brain (see animation), until finally his doctors decided to operate. To their immense surprise, they pulled out a 1 centimetre-long ribbon-shaped worm. It looked like a tapeworm, but was unlike any seen before in the UK, so a sample of its tissue was sent to Hayley Bennett and her colleagues at the Wellcome Trust Sanger Institute in Cambridge, UK. Genetic sequencing identified it as Spirometra erinaceieuropaei, a rare species of tapeworm found in China, South Korea, Japan and Thailand. Just 300 human infections have been reported since 1953, and not all of them in the brain. © Copyright Reed Business Information Ltd.

Keyword: Brain imaging
Link ID: 20344 - Posted: 11.21.2014

By Pippa Stephens Health reporter, BBC News Women are more likely than men to display symptoms of depression when in a position of authority at work, according to US scientists. In men, authority, such as the ability to hire and fire people, decreases depressive symptoms, the study said. The study, published in the Journal of Health and Social Behaviour, looked at 2,800 middle-aged men and women. One expert said the study showed the need for more women in authority and more varied female role models. Scientists at the University of Texas at Austin interviewed 1,300 male and 1,500 female graduates from Wisconsin high schools over the phone in 1993 and 2004, when they were aged about 54 and 64. Researchers asked participants about job authority and about the number of days in the past week they felt depressive symptoms, such as feeling sad and thinking one's life is a failure. When the job included hiring, firing and influencing pay, women were predicted to have a 9% increased rate of depressive symptoms than women without authority. Meanwhile, men had a 10% decreased rate of depressive symptoms. The study said it controlled for other factors that could cause depression, such as hours worked per week, whether people had flexible hours and how often workers were checked by a supervisor. Scientists also said men were more likely to decide when to start and finish work than women and were less frequently monitored by their advisers. Lead researcher Tetyana Pudrovska said: "These women have more education, higher incomes, more prestigious occupations, and higher levels of job satisfaction and autonomy than women without job authority. Yet they have worse mental health than lower status women." BBC © 2014

Keyword: Depression; Sexual Behavior
Link ID: 20343 - Posted: 11.21.2014

By Tara Parker-Pope Most people who drink to get drunk are not alcoholics, suggesting that more can be done to help heavy drinkers cut back, a new government report concludes. The finding, from a government survey of 138,100 adults, counters the conventional wisdom that every “falling-down drunk” must be addicted to alcohol. Instead, the results from the National Survey on Drug Use and Health show that nine out of 10 people who drink too much are not addicts, and can change their behavior with a little — or perhaps a lot of — prompting. “Many people tend to equate excessive drinking with alcohol dependence,’’ sad Dr. Robert Brewer, who leads the alcohol program at the Centers for Disease Control and Prevention. “We need to think about other strategies to address these people who are drinking too much but who are not addicted to alcohol.” Excessive drinking is viewed as a major public health problem that results in 88,000 deaths a year, from causes that include alcohol poisoning and liver disease, to car accidents and other accidental deaths. Excessive drinking is defined as drinking too much at one time or over the course of a week. For men, it’s having five or more drinks in one sitting or 15 drinks or more during a week. For women, it’s four drinks on one occasion or eight drinks over the course of a week. Underage drinkers and women who drink any amount while pregnant also are defined as “excessive drinkers.” Surprisingly, about 29 percent of the population meets the definition for excessive drinking, but 90 percent of them do not meet the definition of alcoholism. That’s good news because it means excessive drinking may be an easier problem to solve than previously believed. © 2014 The New York Times Company

Keyword: Drug Abuse
Link ID: 20342 - Posted: 11.21.2014

By Bethany Brookshire WASHINGTON — Estrogen can protect the brain from harmful inflammation following traumatic injury, a new study in zebra finches suggests. Boosting levels of the sex hormone in the brain might help prevent the cell loss that occurs following damage from injuries such as stroke. Estrogen levels quadrupled around the damaged area in both male and female zebra finches after researchers gave them experimental brain injuries, Colin Saldanha and colleagues at American University in Washington, D.C., reported November 17 at the annual meeting of the Society for Neuroscience. When the scientists prevented finch brains from making estrogen, inflammatory proteins at damaged sites increased. The helpful estrogen didn’t come from gonads. It’s made within the brain by support cells called astrocytes close to the injury. Injury inflames the brain. Initially, this inflammation recruits helpful cells to the damaged area and aids in recovery. But the long-term presence of inflammatory proteins can cause harm, killing off brain cells and reducing functions such as movement and memory. The researchers hope that by understanding how estrogen reduces inflammatory proteins, therapies might boost this natural estrogen production to keep harmful inflammation at bay. © Society for Science & the Public 2000 - 2014.

Keyword: Hormones & Behavior; Brain Injury/Concussion
Link ID: 20341 - Posted: 11.21.2014

By RONI CARYN RABIN The Food and Drug Administration on Thursday approved a powerful long-acting opioid painkiller, alarming some addiction experts who fear that its widespread use may contribute to the rising tide of prescription drug overdoses. The new drug, Hysingla, and another drug approved earlier this year, Zohydro, contain pure hydrocodone, a narcotic, without the acetaminophen used in other opioids. But Hysingla is to be made available as an “abuse-deterrent” tablet that cannot easily be broken or crushed by addicts looking to snort or inject it. Nearly half of the nation’s overdose deaths involved painkillers like hydrocodone and oxycodone, according to a 2010 study by the Centers for Disease Control and Prevention. More than 12 million people used prescription painkillers for nonmedical reasons that year, according to the study. Prescription opioid abuse kills more adults annually than heroin and cocaine combined, and sends 420,000 Americans to emergency rooms every year, according to the C.D.C. Hysingla, however, will not be not abuse-proof, said officials at the F.D.A. and the drug’s manufacturer, Purdue Pharma. Its extended-release formulation, a pill to be taken once every 24 hours by patients requiring round-the-clock pain relief, will contain as much as 120 milligrams of hydrocodone. The F.D.A. warned that doses of 80 milligrams or more “should not be prescribed to people who have not previously taken an opioid medication,” but officials described the abuse-deterrent formulation as a step forward. © 2014 The New York Times Company

Keyword: Pain & Touch; Drug Abuse
Link ID: 20340 - Posted: 11.21.2014

By Jyoti Madhusoodanan Eurasian jays are tricky thieves. They eavesdrop on the noises that other birds make while hiding food in order to steal the stash later, new research shows. Scientists trying to figure out if the jays (Garrulus glandarius) could remember sounds and make use of the information placed trays of two materials—either sand or gravel—in a spot hidden from a listening jay’s view. Other avian participants of the same species, which were given a nut, cached the treat in one of the two trays. Fifteen minutes later, the listening bird was permitted to hunt up the stash (video). When food lay buried in a less noisy material such as sand, jays searched randomly. But if they heard gravel being tossed around as treats were hidden, they headed to the pebbles to pilfer the goods. Previous studies have shown that jays—like crows, ravens, and other bird burglars that belong to the corvid family—can remember where they saw food being hidden and return to the spot to look for the cache. But these new results, published in Animal Cognition this month, provide the first evidence that these corvids can also recollect sounds to locate and steal stashes of food. In their forest homes, where birds are heard more often than they are seen, this sneaky strategy might give eavesdropping jays a better chance at finding hidden feasts.

Keyword: Hearing
Link ID: 20339 - Posted: 11.21.2014

By Elizabeth Pennisi The microbes that live in your body outnumber your cells 10 to one. Recent studies suggest these tiny organisms help us digest food and maintain our immune system. Now, researchers have discovered yet another way microbes keep us healthy: They are needed for closing the blood-brain barrier, a molecular fence that shuts out pathogens and molecules that could harm the brain. The findings suggest that a woman's diet or exposure to antibiotics during pregnancy may influence the development of this barrier. The work could also lead to a better understanding of multiple sclerosis, in which a leaky blood-brain barrier may set the stage for a decline in brain function. The first evidence that bacteria may help fortify the body’s biological barriers came in 2001. Researchers discovered that microbes in the gut activate genes that code for gap junction proteins, which are critical to building the gut wall. Without these proteins, gut pathogens can enter the bloodstream and cause disease. In the new study, intestinal biologist Sven Pettersson and his postdoc Viorica Braniste of the Karolinska Institute in Stockholm decided to look at the blood-brain barrier, which also has gap junction proteins. They tested how leaky the blood-brain barrier was in developing and adult mice. Some of the rodents were brought up in a sterile environment and thus were germ-free, with no detectable microbes in their bodies. Braniste then injected antibodies—which are too big to get through the blood-brain barrier—into embryos developing within either germ-free moms or moms with the typical microbes, or microbiota. © 2014 American Association for the Advancement of Science

Keyword: Obesity
Link ID: 20338 - Posted: 11.20.2014

Sara Reardon A technique that makes mouse brains transparent shows how the entire brain responds to cocaine addiction and fear. The findings could uncover new brain circuits involved in drug response. In the technique, known as CLARITY, brains are infused with acrylamide, which forms a matrix in the cells and preserves their structure along with the DNA and proteins inside them. The organs are then treated with a detergent that dissolves opaque lipids, leaving the cells completely clear. To test whether CLARITY could be used to show how brains react to stimuli, neuroscientists Li Ye and Karl Deisseroth of Stanford University in California engineered mice so that their neurons would make a fluorescent protein when they fired. (The system is activated by the injection of a drug.) The researchers then trained four of these mice to expect a painful foot shock when placed in a particular box; another set of mice placed in the box received cocaine, rather than shocks. Once the mice had learned to associate the box with either pain or an addictive reward, the researchers tested how the animals' brains responded to the stimuli. They injected the mice with the drug that activated the fluorescent protein system, placed them in the box and waited for one hour to give their neurons time to fire. The next step was to remove the animals' brains, treat them with CLARITY, and image them using a system that could count each fluorescent cell across the entire brain (see video). A computer combined these images into a model of a three-dimensional brain, which showed the pathways that lit up when mice were afraid or were anticipating cocaine. © 2014 Nature Publishing Group

Keyword: Drug Abuse; Brain imaging
Link ID: 20337 - Posted: 11.20.2014

By Emily Underwood WASHINGTON, D.C.—Rapid changes unfold in the brain after a person's hand is amputated. Within days—and possibly even hours—neurons that once processed sensations from the palm and fingers start to shift their allegiances, beginning to fire in response to sensations in other body parts, such as the face. But a hand transplant can bring these neurons back into the fold, restoring the sense of touch nearly back to normal, according to a study presented here this week at the annual conference of the Society for Neuroscience. To date, roughly 85 people worldwide have undergone hand replant or transplant surgery, an 8- to 10-hour procedure in which surgeons reattach the bones, muscles, nerves, blood vessels, and soft tissue between the patient's severed wrist and their own hand or one from a donor, often using a needle finer than a human hair. After surgery, studies have shown that it takes about 2 years for the peripheral nerves to regenerate, with sensation slowly creeping through the palm and into the fingertips at a rate of roughly 2 mm per day, says Scott Frey, a cognitive neuroscientist at the University of Missouri, Columbia. Even once the nerves have regrown, the surgically attached hand remains far less sensitive to touch than the original hand once was. One potential explanation is that the brain's sensory "map" of the body—a series of cortical ridges and folds devoted to processing touch in different body parts—loses its ability to respond to the missing hand in the absence of sensory input, Frey says. If that's true, the brain may need to reorganize that sensory map once again in order to fully restore sensation. © 2014 American Association for the Advancement of Science

Keyword: Pain & Touch; Regeneration
Link ID: 20336 - Posted: 11.20.2014

By Kate Baggaley WASHINGTON — Being stroked in the right place at the right speed activates specialized nerve fibers. The caresses that people rate most pleasant line up with the probable locations of the fibers on the skin, new research suggests. “Touch is important in terms of our physical health and our psychological well-being,” said Susannah Walker, who presented the research November 17 at the annual meeting of the Society for Neuroscience. “But very little attention has been paid to the neurological basis of that effect.” Sensors in the skin known as C-tactile afferents respond strongly to being stroked at between three and 10 centimeters per second. The sensors send signals to the brain that make touch rewarding, says Walker, a neuroscientist at Liverpool John Moores University in England. Walker and a colleague played videos for 93 participants, showing a hand caressing a person’s palm, back, shoulder or forearm, either at 5 cm/s or 30 cm/s. Participants rated the 5 cm/s stroking — the best speed to get the skin’s sensors firing — as the most pleasant, except on the palm, where there are no stroking sensors. The back got the highest pleasantness ratings, forearms lowest. The spots where people like to be touched may not line up with the areas traditionally considered most sensitive. Though less finely attuned to texture or temperature than the hands or face, the back and shoulders are sensitive to a different, social sort of touch. © Society for Science & the Public 2000 - 2014.

Keyword: Pain & Touch; Emotions
Link ID: 20335 - Posted: 11.20.2014