Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior
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by Helen Thomson KULLERVO HYNYNEN is preparing to cross neuroscience's final frontier. In July he will work with a team of doctors in the first attempt to open the blood-brain barrier in humans – the protective layer around blood vessels that shields our most precious organ against threats from the outside world. If successful, the method would be a huge step in the treatment of pernicious brain diseases such as cancer, Parkinson's and Alzheimer's, by allowing drugs to pass into the brain. The blood-brain barrier (BBB) keeps toxins in the bloodstream away from the brain. It consists of a tightly packed layer of endothelial cells that wrap around every blood vessel throughout the brain. It prevents viruses, bacteria and any other toxins passing into the brain, while simultaneously ushering in vital molecules such as glucose via specialised transport mechanisms. The downside of this is that the BBB also completely blocks the vast majority of drugs. Exceptions include some classes of fat and lipid-soluble chemicals, but these aren't much help as such drugs penetrate every cell in the body – resulting in major side effects. "Opening the barrier is really of huge importance. It is probably the major limitation for innovative drug development for neurosciences," says Bart De Strooper, co-director of the Leuven Institute for Neuroscience and Disease in Belgium. © Copyright Reed Business Information Ltd.
Link ID: 19748 - Posted: 06.19.2014
By Michelle Roberts Health editor, BBC News online Scientists say they have devised a helmet that can quickly determine whether a patient has had a stroke. It could speed diagnosis and treatment of stroke to boost chances of recovery, the scientists say. The wearable cap bounces microwaves off the brain to determine whether there has been a bleed or clot deep inside. The Swedish scientists who made the device plan to give it to ambulance crews to test after successful results in early studies with 45 patients. When a person has a stroke, doctors must work quickly to limit any brain damage. If it takes more than four hours to get to hospital and start treatment, parts of their brain tissue may already be dying. But to give the best treatment, doctors first need to find out if the stroke is caused by a leaky blood vessel or one blocked by a clot. A computerised tomography (CT) scan will show this, but it can take some time to organise one for a patient, even if they have been admitted as an emergency to a hospital that has one of these scanners. Any delay in this "golden hour" of treatment opportunity could hamper recovery. To speed up the process, researchers in Sweden, from Chalmers University of Technology, Sahlgrenska Academy and Sahlgrenska University Hospital, have come up with a mobile device that could be used on the way to hospital. The helmet uses microwave signals - the same as the ones emitted by microwave ovens and mobile phones but much weaker - to build a picture of what is going on throughout the brain. BBC © 2014
In a new study, scientists at the National Institutes of Health took a molecular-level journey into microtubules, the hollow cylinders inside brain cells that act as skeletons and internal highways. They watched how a protein called tubulin acetyltransferase (TAT) labels the inside of microtubules. The results, published in Cell, answer long-standing questions about how TAT tagging works and offer clues as to why it is important for brain health. Microtubules are constantly tagged by proteins in the cell to designate them for specialized functions, in the same way that roads are labeled for fast or slow traffic or for maintenance. TAT coats specific locations inside the microtubules with a chemical called an acetyl group. How the various labels are added to the cellular microtubule network remains a mystery. Recent findings suggested that problems with tagging microtubules may lead to some forms of cancer and nervous system disorders, including Alzheimer’s disease, and have been linked to a rare blinding disorder and Joubert Syndrome, an uncommon brain development disorder. “This is the first time anyone has been able to peer inside microtubules and catch TAT in action,” said Antonina Roll-Mecak, Ph.D., an investigator at the NIH’s National Institute of Neurological Disorders and Stroke (NINDS), Bethesda, Maryland, and the leader of the study. Microtubules are found in all of the body’s cells. They are assembled like building blocks, using a protein called tubulin. Microtubules are constructed first by aligning tubulin building blocks into long strings. Then the strings align themselves side by side to form a sheet. Eventually the sheet grows wide enough that it closes up into a cylinder. TAT then bonds an acetyl group to alpha tubulin, a subunit of the tubulin protein.
Link ID: 19729 - Posted: 06.14.2014
By JAMES GORMAN The National Institutes of Health set an ambitious $4.5 billion price tag on its part of President Obama’s Brain Initiative on Thursday, stamping it as an effort on the scale of the Human Genome Project. The goals of the Brain Initiative were clearly grand when Mr. Obama announced it a year ago — nothing less than developing and applying new technology to crack the toughest unsolved puzzles of how the brains of humans and animals function. The hope is to lay a foundation for future advances in the medical treatment of brain disorders. But the initiative began with $110 million budgeted for 2014, shared by three major entities: the National Science Foundation; the Defense Advanced Research Projects Agency; and the N.I.H., which has a $40 million share. By calling for such a major commitment, to be spread over 12 years, the institutes answered concerns among neuroscientists about the initial level of funding. “This is a realistic amount of money,” said Dr. Eric R. Kandel, director of the Kavli Institute for Brain Science at Columbia University, who, like some other neuroscientists, had been skeptical of what could be accomplished with the funding committed when the initiative was announced about a year ago. Gerald Rubin, the executive director of the Janelia Farm Research Campus in Virginia, also found that this budget request allayed some of his concerns, but not all. “I am much more concerned about convincing Congress to fund the Brain Initiative at this level,” he said. © 2014 The New York Times Company
Keyword: Brain imaging
Link ID: 19697 - Posted: 06.06.2014
Sarah C. P. Williams This, in all its molecular complexity, is what the bulging end of a single neuron looks like. A whopping 300,000 proteins come together to form the structure, which is less than a micrometer wide, hundreds of times smaller than a grain of sand. This particular synapse is from a rat brain. It’s where chemical signals called neurotransmitters are released into the space between neurons to pass messages from cell to cell. To create a 3D molecular model of the structure, researchers first isolated the synapses of rat neurons and turned to classic biochemistry to identify and quantify the molecules present at every stage of the neurotransmitter release cycle. Then, they used microscopy to pinpoint the location of each protein. Some proteins—like the red patches of SNAP25 visible in the video at 0:14—aid in the release of vesicles, tiny spheres full of neurotransmitters. Others—like the green, purple, and red rods at 0:45—help the synapse maintain its overall structure. Different proteins surround vesicles when they’re inside the synapse—the circles scattered throughout the structure at 0:56—than when the vesicles are forming at the edge of the synapse—as shown at 2:08. Researchers can use the model, described online today in Science, to better understand how neurons function and what goes wrong in brain disorders. (Video credit: Wilhelm et al. 2014, Science) © 2014 American Association for the Advancement of Science.
Keyword: Brain imaging
Link ID: 19678 - Posted: 05.31.2014
Elizabeth Norton Cultures around the world have long assumed that women are hardwired to be mothers. But a new study suggests that caring for children awakens a parenting network in the brain—even turning on some of the same circuits in men as it does in women. The research implies that the neural underpinnings of the so-called maternal instinct aren't unique to women, or activated solely by hormones, but can be developed by anyone who chooses to be a parent. "This is the first study to look at the way dads' brains change with child care experience," says Kevin Pelphrey, a neuroscientist at Yale University who was not involved with the study. "What we thought of as a purely maternal circuit can also be turned on just by being a parent—which is neat, given the way our culture is changing with respect to shared responsibility and marriage equality." The findings come from an investigation of two types of households in Israel: traditional families consisting of a biological mother and father, in which the mother assumed most of the caregiving duties, though the fathers were very involved; and homosexual male couples, one of whom was the biological father, who'd had the child with the help of surrogate mothers. The two-father couples had taken the babies home shortly after birth and shared caregiving responsibilities equally. All participants in the study were first-time parents. Researchers led by Ruth Feldman, a psychologist and neuroscientist at Bar-Ilan University in Ramat Gan, Israel, visited with the families in their homes, videotaping each parent with the child and then the parents and children alone. The team, which included collaborators at the Tel Aviv Sourasky Medical Center in Israel, also took saliva samples from all parents before and after the videotaped sessions to measure oxytocin—a hormone that's released at times of intimacy and affection and is widely considered the "trust hormone.” Within a week of the home visit, the participants underwent functional magnetic resonance imaging scanning to determine how their brains reacted to the videotapes of themselves with their infants. © 2014 American Association for the Advancement of Science
By JAMES GORMAN H. Sebastian Seung is a prophet of the connectome, the wiring diagram of the brain. In a popular book, debates and public talks he has argued that in that wiring lies each person’s identity. By wiring, Dr. Seung means the connections from one brain cell to another, seen at the level of the electron microscope. For a human, that would be 85 billion brain cells, with up to 10,000 connections for each one. The amount of information in the three-dimensional representation of the whole connectome at that level of detail would equal a zettabyte, a term only recently invented when the amount of digital data accumulating in the world required new words. It equals about a trillion gigabytes, or as one calculation framed it, 75 billion 16-gigabyte iPads. He is also a realist. When he speaks publicly, he tells his audiences, “I am my connectome.” But he can be brutally frank about the limitations of neuroscience. “We’ve failed to answer simple questions,” he said. “People want to know, ‘What is consciousness?’ And they think that neuroscience is up to understanding that. They want us to figure out schizophrenia and we can’t even figure out why this neuron responds to one direction and not the other.” This mix of intoxicating ideas, and the profound difficulties of testing them, not only defines Dr. Seung’s career but the current state of neuroscience itself. He is one of the stars of the field, and yet his latest achievement, in a paper published this month, is not one that will set the world on fire. He and his M.I.T. colleagues have proposed an explanation of how a nerve cell in the mouse retina — the starburst amacrine cell — detects the direction of motion. If he’s right, this is significant work. But it may not be what the public expects, and what they have been led to expect, from the current push to study the brain. © 2014 The New York Times Company
By JAMES GORMAN Crowd-sourced science has exploded in recent years. Foldit enlists users to help solve scientific puzzles such as how proteins are put together. Zooniverse hosts dozens of projects, including searching for planets and identifying images of animals caught on automatic cameras. Eyewire, which came out of H. Sebastian Seung’s lab at the Massachusetts Institute of Technology about a year and a half ago, is neuroscience’s entry into the field. The EyeWirers, as the players are called, have scored their first scientific success, contributing to a paper in the May 4 issue of Nature by Dr. Seung and his M.I.T. colleagues that offers a solution to a longstanding problem in how motion is detected. Anyone can sign up online, learn to use the software and start working on what Amy Robinson, the creative director of Eyewire, calls a “3-D coloring book.” The task is something like tracing one piece of yarn through an extremely tangled ball. More than 130,000 players in 145 countries, at last count, work on a cube that represents a bit of retinal tissue 4.5 microns on a side. The many branches of neurons are densely packed within. A micron is .00004 inches or, in Eyewire’s calculus, about one-tenth the width of a human hair. Some of the players spend upward of 40 hours a week on Eyewire. These cubes are created by an automated process in which electron microscopes make images of ultrathin slices of brain tissue. Computers then analyze and compile the data to create a three-dimensional representation of a cube of tissue with every neuron and connection visible. © 2014 The New York Times Company
Eliana Dockterman @edockterman A new study that could affect whether adoption agencies are willing to work with gay couples shows that after adopting, gay men's brain activity resembles that of both new moms and new dads Research has shown that a new mother’s brain activity changes after having a baby. Turns out, gay men’s pattern of brain activity also adapts to parenthood, and resembles that of both new moms and new dads, in findings published Monday. A study published Monday in the Proceedings of the National Academy of Sciences sought to determine whether mothers’ brains became hyper-reactive to emotional cues, like hearing their child cry after birth, because of hormonal changes or parenting experience. Researchers videotaped 89 new moms and dads taking care of their infants at home. They then measured parents’ brain activity in an MRI while the parents watched videos in which their children were not featured, followed by the footage shot in their home with their kids. The 20 mothers in the study—all of whom were the primary caregivers—had heightened activity in the brain’s emotion-processing regions; the amygdala, a set of neurons that processes emotions, was five times more active than the baseline. The 21 heterosexual fathers had increased activity in their cognitive circuits, which helped them determine which of the baby’s body movements indicated the need for a new diaper and which ones signaled hunger. The 48 gay fathers’ brain waves, on the other hand, responded similarly to both the heterosexual mom and dad. Their emotional circuits were as active as mothers’, and their cognitive circuits were as active as the fathers’. Researchers also found that the more time a gay father spent with the baby, the greater a connection there was between the emotional and cognitive structures.
By Neuroskeptic Nothing that modern neuroscience can detect, anyway. This is the message of a provocative article by Pace University psychologist Terence Hines, just published in Brain and Cognition: Neuromythology of Einstein’s brain As Hines notes, the story of how Einstein’s brain was preserved is well known. When the physicist died in 1955, his wish was to be cremated, but the pathologist who performed the autopsy decided to save his brain for science. Einstein’s son Hans later gave his blessing to this fait accompli. Samples and photos of the brain were then made available to neuroscientists around the world, who hoped to discover the secret of the great man’s genius. Many have claimed to have found it. But Hines isn’t convinced. Some researchers, for instance, have used microscopy to examine Einstein’s brain tissue on a histological (cellular) level. Most famous amongst these studies is Diamond et al, who in 1985 reported that Einstein’s brain had a significantly higher proportion of glial cells than those of matched, normal control brains. However, Hines points out that this ‘finding’ may have been a textbook example of the multiple-comparisons problem: Diamond et al. (1985) reported four different t-tests, each comparing Einstein’s brain to the brains of the controls. Only one of the four tests performed was significant at the .05 level. Although only the results of the neuron to glial cell ratios were reported by Diamond et al. (1985), the paper makes it clear that at least six other dependent measures were examined: (1) number of neurons, (2) total number of glial cells, (3) number of astrocytes, (4) number of oligodendrocytes, (5) neuron to astrocyte ratio and (6) neuron to oligodendrocyte ratio. Thus a total of seven different dependent measures were examined in four different brain areas for a total of 28 comparisons… one p less than 0.05 result out of 28 is not surprising. Other histological studies followed from other researchers, but Hines says that they do not present a coherent picture of clear differences:
The Presidential Commission for the Study of Bioethical Issues today released its first set of recommendations for integrating ethics into neuroscience research in the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. Last July, President Barack Obama charged the commission with identifying key ethical questions that may arise through the BRAIN Initiative and wider neuroscience research. The report is “a dream come true,” says Judy Illes, a neuroethicist at the University of British Columbia in Vancouver, Canada, who was a guest presenter to the commission. Brain research raises unique ethical issues because it “strikes at the very core of who we are,” said political scientist and philosopher Amy Gutmann of the University of Pennsylvania, who chairs the commission, in a call with reporters yesterday. Specific areas of concern identified in the report include questions of brain privacy raised by advances in neuroimaging research; whether research participants and patients with dementia can give informed consent to participate in experimental trials; and research into cognitive enhancement, which raises “issues of distributive justice and fairness,” Gutmann says. Parsing hope from hype is key to ethical neuroscience research and its application, Gutmann notes. Citing the troubled ethical history of psychosurgery in the United States, in which more than 40,000 people were lobotomized based on shaky evidence that the procedure could treat psychiatric illnesses such as schizophrenia and depression, Gutmann cautions that a similar ethical derailment is possible in contemporary neuroscience research. A misstep with invasive experimental treatments such as deep brain stimulation surgery would not only be tragic for patients, but have “devastating consequences” for scientific progress, she says. © 2014 American Association for the Advancement of Science
By Melissa Hogenboom Science reporter, BBC Radio Science Neuroscience is a fast growing and popular field, but despite advances, when an area of the brain 'lights up" it does not tell us as much as we'd like about the inner workings of the mind. Many of us have seen the pictures and read the stories. A beautiful picture of the brain where an area is highlighted and found to be fundamental for processes like fear, disgust or impaired social ability. There are so many stories it can be easy to be swayed into thinking that much more of the brain's mystery has been solved than is the case. The technology is impressive but one of the most popular scanning methods - functional magnetic resonance imaging (fMRI) actually measures regional regional changes of blood flow to areas of the brain, not our neurons directly. Researchers use it when they want to understand what part of the brain is involved in a particular task. They can place a person in a brain scanner and see which areas become active. The areas that light up are then inferred to be important for that task, but the resulting images and phrase "lighting up the brain" can lead to over interpretation. Neuroscientist Molly Crocket from University College London explains that while fMRI is extremely useful, we are still very far from being able to read an individual's mind from a scan. "There's a misconception that's still rather common that you can look at someone's brain imaging data and be able to read off what they're thinking and feeling. This is certainly not the case," Dr Crocket told the BBC's Inside Science programme. 19th Century brain "A study will have been done which tells us something about the brain, but what [the public] really want to do is make the leap and understand the mind." She cites an article with the headline, "You love your iPhone, literally". In this case a team saw an area previously associated with love - the insula - was active when participants watched videos of a ringing iPhone. BBC © 2014
By Gabriella Rosen Kellerman By 1664, the year he published his most famous book of neuroanatomy, Cerebri Anatome, Dr. Thomas Willis was already renowned in Britain for saving lives. Fourteen years earlier, the corpse of executed murderer Anne Green had been delivered to Willis and some of his colleagues for autopsy. Upon opening the coffin—the story goes—the doctors heard a gasp. Ms. Green, they discovered, had been hanged but not executed. Thanks to the resuscitation efforts of Willis and his colleagues, Green survived, and was given a stay of execution. She died fifteen years later. The episode supposedly drew jealousy from Willis’s contemporaries, who could have had no idea just how many lives Willis’s work would one day save. Among the important discoveries included in Cerebri Anatome, considered the founding text of neurology, is the Circle of Willis, a map of the interconnecting arteries at the base of the brain. Such circular connections among arteries are called anastomoses. They enable blood to reach vital tissue along multiple routes so that when one is blocked, the blood has an alternative outlet. The Circle of Willis is perhaps most important because of its implications for stroke. Stroke, which is the third leading cause of death in this country, occurs when blood flow to the brain is disrupted. This can occur when an artery gets blocked with plaque or a clot (called an ischemic stroke) or when at artery bursts (called hemorrhagic stroke). Many of these problems, particularly the latter kind of stroke, occur in the Circle of Willis. © 2014 Scientific American
Link ID: 19564 - Posted: 05.03.2014
By Greg Miller As a journalist who writes about neuroscience, I’ve gotten a lot of super enthusiastic press releases touting a new breakthrough in using brain scans to read people’s minds. They usually come from a major university or a prestigious journal. They make it sound like a brave new future has suddenly arrived, a future in which brain scans advance the cause of truth and justice and help doctors communicate with patients whose minds are still active despite their paralyzed bodies. Amazing, right? Drop everything and write a story! Well, not so fast. Whenever I read these papers and talk to the scientists, I end up feeling conflicted. What they’ve done–so far, anyway–really doesn’t live up to what most people have in mind when they think about mind reading. Then again, the stuff they actually can do is pretty amazing. And they’re getting better at it, little by little. In pop culture, mind reading usually looks something like this: Somebody wears a goofy-looking cap with lots of wires and blinking lights while guys in white lab coats huddle around a monitor in another room to watch the movie that’s playing out in the person’s head, complete with cringe-inducing internal monologue. We are not there yet. “We can decode mental states to a degree,” said John-Dylan Haynes, a cognitive neuroscientist at Charité-Universitätsmedizin Berlin. “But we are far from a universal mind reading machine. For that you would need to be able to (a) take an arbitrary person, (b) decode arbitrary mental states and (c) do so without long calibration.” © 2014 Condé Nast.
By JAMES GORMAN SAN DIEGO — Dr. Karl Deisseroth is having a very early breakfast before the day gets going at the annual meeting of the Society for Neuroscience. Thirty thousand people who study the brain are here at the Convention Center, a small city’s worth of badge-wearing, networking, lecture-attending scientists. For Dr. Deisseroth, though, this crowd is a bit like the gang at Cheers — everybody knows his name. He is a Stanford psychiatrist and a neuroscientist, and one of the people most responsible for the development of optogenetics, a technique that allows researchers to turn brain cells on and off with a combination of genetic manipulation and pulses of light. He is also one of the developers of a new way to turn brains transparent, though he was away when some new twists on the technique were presented by his lab a day or two earlier. “I had to fly home to take care of the kids,” he explained. He went home to Palo Alto to be with his four children, while his wife, Michelle Monje, a neurologist at Stanford, flew to the conference for a presentation from her lab. Now she was home and, here he was, back at the conference, looking a bit weary, eating eggs, sunny side up, and talking about the development of new technologies in science. A year ago, President Obama announced an initiative to invest in new research to map brain activity, allocating $100 million for the first year. The money is a drop in the bucket compared with the $4.5 billion the National Institutes of Health spends annually on neuroscience, but it is intended to push the development of new techniques to investigate the brain and map its pathways, starting with the brains of small creatures like flies. Cori Bargmann of Rockefeller University, who is a leader of a committee at the National Institutes of Health setting priorities for its piece of the brain initiative, said optogenetics was a great example of how technology could foster scientific progress. © 2014 The New York Times Company
Keyword: Brain imaging
Link ID: 19520 - Posted: 04.22.2014
By JAMES GORMAN As the Brain Initiative announced by President Obama a year ago continues to set priorities and gear up for what researchers hope will be a decade-long program to understand how the brain works, two projects independent of that effort reached milestones in their brain mapping work. Both projects, one public and one private, are examples of the widespread effort in neuroscience to create databases and maps of brain structure and function that can serve as a foundation for research. While the Obama initiative is concentrating on the development of new tools, that research will build on and use the data being acquired in projects like these. One group of 80 researchers, working as part of a consortium of institutions funded by the National Institute of Mental Health, reported that it had mapped the genetic activity of the human fetal brain. Among other initial findings, the map, the first installment of an atlas of the developing human brain called BrainSpan, confirmed the significance of areas thought to be important in the development of autism. A group of 33 researchers, all but one at the Allen Institute for Brain Science, announced an atlas of the mouse brain showing the connections among 295 different regions. Ed Lein, an investigator at Allen, was the senior author on the fetal brain paper. He said the research required making sections only 20 microns thick, up to 3,500 for each of four brains, two from fetuses at 15 weeks of development and two from about 21 weeks. The researchers measured the activity of 20,000 genes in 300 different brain structures. One interesting finding, Dr. Lein said, was that “95 percent of the genome was used,” meaning almost all of the genes were active during brain development, significantly more than in adult brains. The team also found many differences from the mouse brain, underscoring the findings that, despite the many similarities in all mammalian brains, only so much can be extrapolated to humans from other animals. © 2014 The New York Times Company
by Ashley Yeager A nerve cell's long, slender tentacle isn’t evenly coated with an insulating sheath as scientists had thought. Instead, many nerve cells in the brains of mice have stretches of these tentacles, called axons, that are naked, researchers report April 18 in Science. The unsheathed feeler can be as long as 80 micrometers. Nerve cells can also have specific patterns in the gaps of the insulating layer, called myelin. The differences in the thickness of that coating may control how fast signals travel between nerve cells, the scientists suggest. The finding could have implications for understanding nerve-based diseases, such as multiple sclerosis, and improve scientists’ understanding of how signals are transmitted in the brain. © Society for Science & the Public 2000 - 2013.
By Melissa Hogenboom Artists have structurally different brains compared with non-artists, a study has found. Participants' brain scans revealed that artists had increased neural matter in areas relating to fine motor movements and visual imagery. The research, published in NeuroImage, suggests that an artist's talent could be innate. But training and environmental upbringing also play crucial roles in their ability, the authors report. As in many areas of science, the exact interplay of nature and nurture remains unclear. Lead author Rebecca Chamberlain from KU Leuven University, Belgium, said she was interested in finding out how artists saw the world differently. "The people who are better at drawing really seem to have more developed structures in regions of the brain that control for fine motor performance and what we call procedural memory," she explained. In their small study, researchers peered into the brains of 21 art students and compared them to 23 non-artists using a scanning method called voxel-based morphometry. Detail of 'Giant Lobster' from NHM specimen collection One artist who has practised for many years is Alice Shirley - here is a detail of her Giant Lobster These detailed scans revealed that the artist group had significantly more grey matter in an area of the brain called the precuneus in the parietal lobe. "This region is involved in a range of functions but potentially in things that could be linked to creativity, like visual imagery - being able to manipulate visual images in your brain, combine them and deconstruct them," Dr Chamberlain told the BBC's Inside Science programme. BBC © 2014
By DENISE GRADY People with severe brain injuries sometimes emerge from a coma awake but unresponsive, leaving families with painful questions. Are they aware? Can they think and feel? Do they have any chance of recovery? A new study has found that PET scans may help answer these wrenching questions. It found that a significant number of people labeled vegetative had received an incorrect diagnosis and actually had some degree of consciousness and the potential to improve. Previous studies using electroencephalogram machines and M.R.I. scanners have also found signs of consciousness in supposedly vegetative patients. “I think these patients are kind of neglected by both medicine and society,” said Dr. Steven Laureys, an author of the new study and the director of the Coma Science Group at the University of Liège in Belgium. “Many of them don’t even see a medical doctor or a specialist for years. So I think it’s very important to ask the question, are they unconscious?” In the United States, 100,000 to 300,000 people are thought to be minimally conscious, and an additional 25,000 are vegetative. In Belgium, the combined incidence of the two conditions is about 150 new cases per year, Dr. Laureys said. An article about the new research was published on Tuesday in The Lancet. Dr. Laureys and his colleagues studied 122 patients with brain injuries, including 41 who had been declared vegetative — awake but with no behavioral signs of awareness. People who are vegetative for a year are thought to have little or no chance of recovering, and the condition can become grounds for withdrawing medical treatment. Terri Schiavo, in a vegetative state for 15 years, died in 2005 in Florida after courts allowed the removal of her feeding tube. © 2014 The New York Times Company
Associated Press NEW YORK -- A small study of casual marijuana smokers has turned up evidence of changes in the brain, a possible sign of trouble ahead, researchers say. The young adults who volunteered for the study were not dependent on pot, nor did they show any marijuana-related problems. "What we think we are seeing here is a very early indication of what becomes a problem later on with prolonged use," things like lack of focus and impaired judgment, said Dr. Hans Breiter, a study author. Longer-term studies will be needed to see if such brain changes cause any symptoms over time, said Breiter, of the Northwestern University Feinberg School of Medicine and Massachusetts General Hospital. Previous studies have shown mixed results in looking for brain changes from marijuana use, perhaps because of differences in the techniques used, he and others noted in Wednesday's issue of the Journal of Neurosciences. The study is among the first to focus on possible brain effects in recreational pot smokers, said Dr. Nora Volkow, director of the National Institute on Drug Abuse. The federal agency helped pay for the work. She called the work important but preliminary. The 20 pot users in the study, ages 18 to 25, said they smoked marijuana an average of about four days a week, for an average total of about 11 joints. Half of them smoked fewer than six joints a week. Researchers scanned their brains and compared the results with those of 20 nonusers who were matched for age, sex and other traits. The results showed differences in two brain areas associated with emotion and motivation - the amygdala and the nucleus accumbens. Users showed higher density than nonusers, as well as differences in shape of those areas. Both differences were more pronounced in those who reported smoking more marijuana. © 2014 Hearst Communications, Inc.