May-June 2002

WHO to Promote Alternative Medicine By EMMA ROSS, AP Medical Writer GENEVA (AP) - In response to a rapid increase in the use of alternative medicine over the last decade, the World Health Organization (news - web sites) has created the first global strategy for traditional medicine. The U.N. health agency aims to bring traditional, or alternative, therapies out of the shadows by intensifying research into their effectiveness and safety, by promoting their proper use and regulation and by helping countries integrate them into their health care services. The strategy, launched Thursday at the annual meeting of the WHO's governing body, is also designed to ensure traditional remedies aren't hijacked and patented by big business and that medicinal plants are not wiped out by overharvesting. Traditional medicine — called complementary or alternative medicine in countries where conventional Western, or modern, medicine dominates — includes remedies, such as ginger root or shark cartilage, and diverse practices, such as acupuncture, yoga, shiatsu massage and aromatherapy. Traditional medicine has been used for millennia in parts of the developing world and remains widespread there. In Africa, 80 percent of the population use traditional therapies, WHO said. In Europe and North America, where more than half of people have been treated with alternative medicine at some time during their lives, use has doubled in the last decade, the agency added. Like conventional drugs, alternative treatments must be used correctly, and as with conventional medications, tragedies have occurred. However, unlike with Western medicine, consumers are mostly deciding for themselves what they use. "There seems to be a growing gap between what you might call the 'uncritical enthusiasts' and the 'uninformed skeptics,'" said Dr. Jonathan Quick, director of WHO's essential drugs and medicines policy unit. "The enthusiasts rave that all of these methods work and don't want to recognize that herbal remedies that are used the wrong way can kill." "On the other hand you've got the uninformed skeptics who don't believe that there's any evidence for any of these and would prefer that they not be around," Quick said. The reality is somewhere in the middle, he said. There is now an urgent need to establish through rigorous scientific testing what works and what doesn't, said Forkel Falkenberg, a professor of international health at Sweden's Karolinska Institute in Stockholm. "This is a very important step for modern science, to engage in understanding the complexity of complementary medicine," Falkenberg said. "One cannot any more marginalize this area. One needs to bring it into the light — to understand what to do with it, how to take away the unsafe practices." He said the WHO's decision to create a strategy for alternative medicine is a clear signal that the field is now being taken seriously. Studies have shown success in treating conditions ranging from malaria and HIV (news - web sites) to high blood pressure and lower back pain. The WHO intends to help countries trying to evaluate therapies by providing guidance on how to conduct the studies. It will also provide countries with expert advice on setting up consumer education programs to help people select the right therapies for the right conditions and remind people that just because something is natural, it doesn't mean it's safe. The health agency will soon publish reports on more than 100 medicinal plants, outlining what they are supposed to be used for, how certain it is that they work and what questions remain. It also plans to advise nations on how to ensure the quality of traditional medicine products and practices. That involves regulation of drugs and proper training and licensing of healers, WHO said. More than 70 countries already regulate herbal medicines, said Dr. Xiaroui Zhang, WHO's coordinator for traditional medicine. "Only through regulation can we try to ensure the quality, safety and efficacy," of traditional remedies, she said. In the Western world, Canada has gone farthest down that path. Seventy percent of people in that country have used alternative medicine and one third of the population uses it on a regular basis, said Dr. Jean Lariviere, a senior medical adviser in Canada's health department. Regulations are expected to be sent to Parliament there by the end of the year, he said. How Babies Acquire Building Blocks Of Speech Affects Later Reading, Language Ability Source:   University Of Washington (http://www.washington.edu) WASHINGTON - One of the scientists leading the effort to understand exactly how infants go about learning language told a White House Summit on Early Childhood Cognitive Development today that the fundamental steps in language acquisition later play a critical role in the ability to read. Patricia Kuhl, co-director of the Center for Mind, Brain and Learning at the University of Washington, explained to more than 350 government, education and community leaders gathered at Georgetown University that new research findings may make it easier to diagnose children with reading problems. "Our studies now show that infants' abilities to distinguish speech sound at 6 months of age correlate with language abilities," she said. "The better infants are at distinguishing the phonetic units - the building blocks of speech - the better they are years later at other more complex language skills. Children with language and reading problems have trouble distinguishing the basic sound units used in speech. "Since early speech skills predict later language skills, there is enormous hope that new tests will allow us to identify, very early, children who are at risk for later language difficulties. Early identification allows for intervention." Kuhl made her comments on the opening day of a two-day summit called "Ready to Read, Ready to Learn," hosted by First Lady Laura Bush. The event is designed to expand awareness of research and highlight proven early-learning activities that parents and educators can use to prepare young children for school. Kuhl called infants "the best learners in the universe" and described her work that shows babies begin learning in the first months of life. Her studies have disclosed, for example, that infants are "citizens of the world" at birth and that early in life they can hear the differences between all the consonants and vowels used in any language. But to learn a specific language, she said, they have to learn which sound distinctions are meaningful in their language. English, for example, separates "R" from "L." Japanese does not. Already by 12 months, infants have the rules down, Kuhl said. "Infants are behaving like a computer without its printer hooked up - they store millions of bits of information before they can speak, simply by listening, and this tunes the infant brain, for example, to English rather than French or Japanese. They do this incredibly early. Infants are mastering language simply by listening to us talk," she said. The language that parents, caretakers and most other people use unconsciously to communicate with infants is called "motherese" or "parentese." Kuhl discovered that this exaggerated, well-formed type of speech is used in cultures around the world and babies prefer and learn from it. Kuhl called for more partnerships between researchers, business leaders, educators and government agencies, not only to support research into early childhood development but also to share the results with parents and teachers. The new UW Center for Mind, Brain and Learning is a model of that kind of cooperation. It is doing interdisciplinary research on early learning and the brain and is partnered with and funded by the Talaris Research Institute, whose mission is to sponsor research and disseminate the results to parents and educators. The National Institutes of Health and National Science Foundation also support the center's work. The center's co-director, Andrew Meltzoff, an expert in cognitive and social development in children, also is participating in the White House summit. "Understanding the developing mind and brain is one of the next great scientific frontiers and holds far-reaching practical implications," Meltzoff said. "A child's language and literacy skills can be improved by what caretakers do during the early preschool years. Scientists have shown that reading books to children in a way that promotes dialogue with them and that playing rhyming games both lay the foundation for reading skills." "The public needs to know what the science shows about how kids learn, and people also need to know what methods don't work or what science hasn't yet tested," Kuhl said. "It's as important to explain that 'parentese' may help infants learn as it is to say that showing flash cards to a 9 month old will not cause them to read any sooner." Meltzoff added, "The goal is not to try to push children too early and create super-kids, but to help all children develop to their maximum potential. Education is the key." NICHD-Funded Researchers Map Physical Basis Of Dyslexia Source:   NIH-National Institute Of Child Health And Human Development (http://www.nih.gov/nichd) A Yale research team funded by the National Institute of Child Health and Human Development (NICHD) has used sophisticated brain imaging technology to show that there is decreased functioning while performing reading tasks in certain brain regions of individuals with the most common form of dyslexia. In their study, the researchers used a technology known as functional magnetic resonance imaging (fMRI), which produces computer-generated images of the brain while it is performing intellectual tasks. With fMRI, the team produced images of an impairment in the brains of dyslexic readers that became apparent when they tried to perform tasks which would require a firm command of the ability to decipher words phonetically. "If you have a broken arm, we can see that on an X-ray," said the study's first author, Sally E. Shaywitz, MD, of the Yale University School of Medicine. "These brain activation patterns now provide us with hard evidence of a disruption in the brain regions responsible for reading..evidence for what has previously been a hidden disability." Dr. Shaywitz explained that the words we speak are made up of individual sounds called phonemes. In spoken language, the brain automatically combines these sounds to form words. To make normal conversation possible, such sound pieces are strung together rapidly..about 8 to 10 per second..and blended so thoroughly that it's often impossible to separate them. For people with dyslexia, the problem arises in converting this natural process to print. Written English is a kind of code: The 26 letters of the alphabet, either singly or in combination with other letters, stand for the 44 letter phonemes in spoken English. Dyslexic readers have extreme difficulty with phonological awareness (breaking spoken words into their component sounds) and with phonetics (the ability to match these letter sounds to the letters that represent them). In their study, Dr. Shaywitz and her coworkers presented 29 dyslexic readers (14 men and 15 women, ages 16-54) and 32 normal readers (16 men and 16 women, ages 18-63) with a battery of reading tasks while observing their brain functioning with the fMRI scanner. Most of these tasks required the readers to manipulate and understand phonologic principals..the skills needed to consciously manipulate the letter sounds in words. The dyslexic readers found it difficult to read nonsense rhyming words, such as "lete" and "jeat." This task is designed to measure the phonologic principals underlying reading and is far more difficult for dyslexic readers to complete than rhyming actual words, which they may have previously memorized. When performing such tasks, the dyslexic readers in the study showed less activation in a brain region linking print skills to the brain's language areas, in comparison to normal readers. Specifically, dyslexic readers showed reduced activity in a large brain region that links the visual cortex and visual association areas (angular gyrus) to the language regions in the superior temporal gyrus (Wernike's area). In the article, the authors noted that their findings are consistent with those of earlier studies of acquired inability to read (alexia). In both alexia and dyslexia, the same brain regions appear to be affected; however, in people with dyslexia, the study shows the impairment is a functional one, whereas in alexia, it has been attributed to a tumor or brain injury due to a stroke. When they performed phonologic tasks, the dyslexic readers also showed activation in the brain region known as Broca's area, which has been associated with spoken language. In contrast, the normal readers did not show any increased activity in Broca's area when reading. Dr. Shaywitz explained that the dyslexic readers may have used this brain region in an attempt to compensate for impairments in the brain regions normally used for phonological skills. "In summary, for dyslexic readers, these brain activation patterns provide evidence of an imperfectly functioning system for segmenting words into their phonologic constituents; accordingly, this disruption is evident when dyslexic readers are asked to respond to increasing demands on phonologic analysis," the authors wrote. "The pattern of relative underactivation in posterior brain regions contrasted with relative overactivation in the anterior regions may provide a neural signature for the phonologic difficulties characterizing dyslexia." Dr. Shaywitz explained that it is too early to use fMRI as a method for diagnosing dyslexia. Nonetheless, the findings have important implications. First, they provide neurologic evidence for the critical role that lack of phonological awareness plays in dyslexia. They also confirm the fundamental neurobiologic nature of dyslexia and provide a neural signature for the phonologic difficulties accompanying the disorder.

New Language Learning Linked To Early Language Experience Source:   McGill University (http://www.mcgill.ca/) The ability to learn a new language is determined by the onset of language experience during early brain development – regardless of the specific form of the language experience. This is the finding of a Canadian study led by Rachel Mayberry of McGill University. Mayberry, director of McGill’s School of Communication Sciences and Disorders, along with Elizabeth Lock of the University of Ottawa and Hena Kazmi of the University of Western Ontario, studied groups of deaf and hearing adults to see how the onset and type of initial language experience affects the ability to learn a new language. The results of the study, which will appear in the May 2 issue of the prestigious journal Nature, show that deaf and hearing adults who experience language in early life perform similarly well in learning a new language later in life – whereas deaf adults who had little language experience in early life showed low levels of performance in a later learned language. These findings are not affected by whether the early language or the later language was signed or spoken. "The timing of our initial language experience during our development – whatever the form of those experiences – strongly influences our capacity to learn language throughout our lives," said Mayberry. "People have always thought that the human capacity to learn language simply disappears as the brain ages," she said. "Our research shows that when the young brain learns language, it develops a lifelong capacity to learn language. When the young brain does not experience language, this language learning capacity does not fully develop." The researchers could not work with hearing subjects only, because all hearing babies experience language from birth. It was necessary to also study individuals who were born deaf, because they often do not experience any language until they are enrolled in special programs. The study was carried out in two parts. First, two groups of deaf adults, one of which was born hearing, were tested for their performance in American Sign Language (ASL), which all had learned at school between the ages of 9 and 15 and had used for more than 20 years. Adults who were born deaf and had little experience of language in early life showed low levels of ASL performance, whereas later deafened adults had high ASL results. The second part of the study compared three groups of adults who had learned English in school between the ages of 4 and 13 and had used it for more than 12 years. Deaf and hearing adults who had experienced either a signed or a spoken language in early life showed similar high levels of performance in the later-learned language, English. However, deaf adults with little early language experience performed poorly in English. A total of 58 adults participated in the study, which was carried out in four Canadian and two U.S. cities over the past four years. The researchers are now looking more specifically at how early language experience affects brain development and how it impacts later reading development. The original news release can be found at http://www.mcgill.ca/releases/2002/may/mayberry/ New Study Identifies Brain Centers For Attention Control Source:   Duke University (http://www.duke.edu/) DURHAM, N.C. -- By asking subjects to direct their attention to particular areas in space while their brains were being scanned by MRI, researchers have mapped brain regions active in the high-level neural control of attention. Like an initial satellite reconnaissance of new terrain, this first mapping represents a key step toward understanding the detailed topography and function of brain regions involved in high-level "executive" control of attention. The researchers reported their findings in an article in the March Nature Neuroscience. They are postdoctoral fellow Joseph Hopfinger and Associate Professor Michael Buonocore of the University of California at Davis, and George R. Mangun, professor of cognitive neuroscience and psychology at Duke University. Their research was sponsored by the National Institute of Mental Health, the Human Frontier Science Program and the National Science Foundation. According to Mangun, basic understanding of attentional control could provide insights into the pathology of such problems as Attentional Deficit Hyperactive Disorder (ADHD), schizophrenia and disorders of attention following brain damage from stroke. Such understanding could also allow measurements of the therapeutic activity of drug treatments in improving attentional functioning. "Before we can understand how such patients are different in their attentional control, we have to know how the process functions normally," said Mangun, who is director of the Duke Center for Cognitive Neuroscience. "With this finding, we are laying some important basic groundwork in mapping the areas involved in attentional control and ultimately understanding their computational structure." Mangun added that the study of such "executive control" in the brain constitutes an important new direction for cognitive neuroscience, which has often focused mainly on how the brain processes sensory input during attention. Mangun and his colleagues used an analytical technique known as "event-related functional MRI" to distinguish brain regions active during attentional control. MRI uses harmless magnetic fields to map the brain, detecting regions of increased blood flow that reflect increased activity of brain cells called neurons. In their experiments, the researchers placed subjects in an MRI machine and had them watch for an arrow to pop up on a video screen. Depending on whether the arrow pointed left or right, after a pause they were to direct their attention, without moving their eyes, to a checkerboard to the left or right of the arrow. Occupying their attention was a task of determining whether the black-and-white checkerboard included any gray squares. By integrating the results of large numbers of such trials, the scientists determined that certain discrete brain areas of the cortex invariably showed activity during the attentional tasks. Principal among these areas are the superior frontal, inferior parietal and superior temporal cortex. The cortex is the thin layer of brain tissue overlying the brain that is responsible for integrating sensory and motor information and for higher brain function. While previous studies of the brain had implicated regions of the cortex in attentional control, Mangun said, the studies had not distinguished between the act of volitional orienting of attention and the subsequent selective processing of sensory inputs that are attended or ignored. "We wanted to distinguish between the neural networks that activate when you initially tell someone to pay attention to something, from those involved in processing what happens as a result," Mangun said. "Thus, in our study, we were able to distinguish the brain regions involved with the initial command to pay attention from the orienting of attention to a spatial location. "It's similar to the distinction in the brain's motor system between what happens when a person decides to reach out for an object and the subsequent neural signals to activate muscle contraction to actually reach out." According to Mangun, the experiment had to be designed to separate the two tasks significantly in time, because of a slight lag between increased neuronal activity and the change in blood flow that would show up on MRI scans. "When you measure blood flow changes, as we do in neuroimaging, the blood flow response to the cue may occur over seconds. And so, if presentation of the cue and the target are separated by only milliseconds, it is very difficult to distinguish the responses." Such a lag meant that even with a 10-second separation of the elements of the experiment, careful analysis of the rise and fall of the "hemodynamic response" was still necessary to unequivocally reveal the brain regions strictly involved in attentional control. Mangun emphasized that the new findings represent only the beginning of efforts to define the brain regions involved in attentional control. Further experiments will use more powerful functional MRI techniques to map the active regions at higher resolution, like distinguishing finer and finer objects in satellite images. The researchers also plan to combine MRI mapping with a complementary technique of electrical recording of brain waves during attentional tasks, a method first reported by Mangun and his colleagues in 1994. While such electrical recording cannot distinguish active regions of the brain as well as MRI, it can offer far more precise measurement of the timing of brain region activity. "Now, we can distinguish the brain regions that are active, but we need to understand in detail which ones are active first, second and third," he said. "Our objective is to distinguish the different mental operations involved, ultimately to understand the detailed computational process of attention." According to Mangun, new experiments also are underway that vary the nature of the attentional task; for example, paying attention to color rather than a spatial location. Such experiments should yield further insight into the basic brain mechanisms of attentional control. The Mangun paper was one of two complementary papers on attentional control published in the issue of Nature Neuroscience. The other paper was by Maurizio Corbetta and colleagues at Washington University School of Medicine in St Louis. In that report, the authors tested the idea that the junction between the temporal and parietal areas played a role in reorienting attention toward stimuli at unexpected locations; and that another region, called the intraparietal sulcus, is involved in voluntary orientation and maintenance of attention at cued locations. While both papers investigated the two major components of attention -- the top-down attentional control processes, and the resulting modulations of perceptual processing -- the Mangun paper isolated and demonstrated the two components. In a News and Views article on the paper, co-authors Roger Tootell and Nouchine Hadjhikhani of Massachusetts General Hospital wrote "... these two papers demonstrate the power of new imaging techniques to resolve complex cognitive operations into their component steps, and to reveal the structures involved in each step. "They are likely to stimulate many future studies, and by combining ever-better imaging methods with other approaches such as patient studies and physiology of non-human primates, we can hope to gain a new depth of understanding of how the brain controls attention." The original news release can be found at http://www.dukenews.duke.edu/Research/mangnatr.htm Memory Isn't "Lost," Just Out Of Sync; Researchers Present Theory Of Memory And Memory Loss Source:   University Of Arkansas For Medical Sciences (http://www.uams.edu/) Little Rock -- Findings published last week in Proceeding of the National Academy of Science (USA) could lead to a better understanding of how our memory changes with age, according to John Hart, Jr., M.D. associate professor in the Reynolds Department of Geriatrics of the UAMS College of Medicine and a co-author of the study. "This new approach to looking at mechanisms of memory via electrical rhythms raises a whole series of questions about how the brain operates and what happens when it doesn't work properly," he explained. The study, conducted by Dr. Hart and co-investigators Scott Slotnick, Ph.D., Lauren Moo, M.D., Michael Kraut, M.D., Ph.D., and R. Lesser, M.D. of Johns Hopkins University, involves a novel explanation for how we recall memories for objects that surround us. The medical researchers suggest that objects occur in your memory by uniting together the different brain regions that make up various parts of the object you are trying to remember. For example, the memory of a dog includes uniting smell, sound, appearance and name. By measuring the electrical rhythms that parts of the brain use to communicate with each other, the team of researchers showed that when the memory of a dog occurs, the thalamus, an important region of the brain that connects areas together, actually regulates the rhythms that connect brain regions. "Memory appears to be a constructive process in combining the features of the items to be remembered rather than simply remembering each object as a whole form," Dr. Slotnick explained. "The thalamus seems to direct or modulate the brain's activity so that the regions needed for memory are connected." "It appears that the electrical signals synchronize the brain regions that store each part of an object's memory so that those areas are connected," Dr. Hart, the study's senior author, continued. "This co-activation of brain regions likely represents the memory of the object itself. It may also explain why we may remember something clearly, and other times we can only come up with parts of the item we are trying to remember. Many times we say 'you know, it has humps, it lives in the desert ...' This may occur when the rhythms don't synchronize with the regions properly. It could also explain why the memory will come to you at a later time." An important implication of the study's association of the thalamus and rhythms to memory is that patients, including those who suffer from Alzheimer's disease, who experience this sort of memory loss may not actually be losing information. Instead, the memory process is being disrupted. Dr. Hart is establishing an imaging and cognition research laboratory at the Donald W. Reynolds Center on Aging at UAMS, where he and other researchers will use memory testing, functional MRI, and measurement of the brain's electrical activity to develop diagnostic tools to identify people with memory disorders. Such a facility may benefit not only Alzheimer's patients, he said, but it will also help stroke and head injury patients, as well as those with schizophrenia. "We want to try to figure out, based on this approach to memory function, what sort of neurotransmitters and brain regions are being disrupted during the memory process. Then we want to see if we can treat patients by regulating this disrupted memory circuit," Dr. Hart explained. The original news release can be found at http://www.uams.edu/info/NewsReleases/2002/050802b.htm

Hopkins Scientists Reveal How Sound Becomes Electric Source:   Johns Hopkins Medical Institutions (http://www.hopkinsmedicine.org/) Scientists from The Center for Hearing and Balance at Johns Hopkins have discovered how tiny cells in the inner ear change sound into an electrical signal the brain can understand. Their finding, published in a recent issue of Nature Neuroscience, could improve the design and programming of hearing aids and cochlear implants by filling in a "black hole" in scientists' understanding of how we hear, say the researchers. "Sound itself is mechanical, a wave that moves, just like the ripples fanning out from a pebble dropped in a lake," says Paul Fuchs, Ph.D., professor of otolaryngology at the Johns Hopkins School of Medicine. "When the inner ear detects this wave, a burst of chemicals is released and a nerve sends an electrical signal to the brain that carries information about the original sound. But the nature of the chemical burst has been a mystery until now." With the help of powerful microscopes, the scientists studied individual cells from rat cochleas, tiny coiled structures deep inside the ear where sound is translated into electricity, the language of the brain. Fuchs and research associate Elisabeth Glowatzki discovered that these so-called "hair cells," named for tiny projections that stick up like a spiky haircut, release a barrage of chemical packets to an adjacent nerve in response to sound. The finding was unexpected, Fuchs says, because hair cells were thought previously only to communicate to nerves by sending a single packet of these chemical transmitters at a time. "Most cells in the brain normally move one packet to their edges, releasing a single dollop of transmitter that travels the short distance to the nerve," he says. "But hair cells deliver a dramatic burst of packets." The scientists suggest this means of communication with nerves may help hair cells carefully control the signals they send. "Hearing requires smooth signaling to accurately detect and distinguish a wide range of sound frequency (pitch) and intensity (volume)," Fuchs says. "Nerves connecting to other cells have to collect the chemical messengers for awhile before they will send an electrical signal to the brain; those nerves have to reach a threshold level of stimulation. And once the signal is sent, the nerve is quiet again," adds Fuchs. "But for hair cells, their continual pumping of messengers toward the nerve may be a kind of fail-safe device that ensures a ready supply of transmitters should the sound continue or change." Hearing aids and cochlear implants are designed to boost or replace the sound-detecting function of hair cells in the cochlea. Fuchs and Glowatzki believe their discovery might help improve the range or accuracy of hearing aids and cochlear implants, they say. The studies were funded by the U.S. National Institute on Deafness and Other Communication Disorders, one of the National Institutes of Health. The original news release can be found at http://www.hopkinsmedicine.org/press/2002/MAY/020502.htm

Rare Brain Mapping Procedure Provides Unique Picture Of Two Areas Concerned With Language Processing And Production Source:   University Of Washington (http://www.cac.washington.edu/) LOS ANGELES -- A unique opportunity to map and test the human brain has yielded new insights into two areas involved in producing and processing of language. David Corina, an assistant professor of psychology at the University of Washington, reported on the roles of two brain regions called Broca's area and the supramarginal gyrus. The findings came from a rare case, a deaf person called S.T. who uses American Sign Language. S.T. underwent a procedure called an awake cortical stimulation mapping, which allows assessment of language and motor functions at specific sites in the brain's left hemisphere. Corina, a fluent signer, and an interdisciplinary team of UW researchers tested the subject and found that electrical stimulation of Broca's area and the supramarginal gyrus created repeated but different kinds of errors in S.T.'s ability to name objects. When Broca's area, which is located in the frontal lobe, was stimulated, S.T. had difficulty making clear hand shapes and specific movements associated with signs. Nonetheless, these sloppy signs resembled the target sign. Corina likens these errors to "mumbling" made in spoken languages. The subject made no effort to self-correct these lax or imperfect signs. Stimulation of the supramarginal gyrus, a small area in the parietal lobe, produced different kind of signing error. With stimulation, S.T. mixed up word meanings and word forms. For example, when shown a picture of a pig and asked to make the sign for it, S.T. made the sign for farm. The two signs are very similar in hand shape, movement and spatial location to the sign pig in American Sign Language, and would be distinct to skilled signer. Comparable errors in English might be saying oyster instead of lobster or plane instead of train. This type of error suggests that the supramarginal gyrus may be an area of the brain important in the selection and combining of word meanings with word forms. Another interesting difference in these language errors was that with stimulation to Broca's area, S.T. made no effort to self-correct his imprecise signing. However, with stimulation to the supramarginal gyrus, he would make successive attempt to produce the correct sign (for oyster he would sign "loyster," then "lobster"). This suggests that stimulation of Broca's area was effecting only the final output of a correctly selected word, while supramarginal gyrus stimulation was effecting the compiling of the word forms, according to Corina. Neuroscientists have long established that a region in the left hemisphere plays a role in language function. In the past decade it also has become evident that left hemis- phere specialization for language extends to deaf people who use sign languages, as well as for those who speak. However, scientists are just beginning to understand the particular contributions specific regions within the left hemisphere play in language processing. The data Corina reported on came from an awake cortical stimulation mapping performed on S.T., a 50-year-old man who was suffering from epileptic brain seizures. The mapping was done prior to an operation called a temporal lobectomy which reduces severe seizures. The mapping procedure helps the neurosurgeon plan this delicate operation. In the mapping, a small electrical current is applied to the exposed cortex of the brain of an awake patient. During electrical stimulation, the patient is asked to name objects and imitate actions. This procedure is often used on speaking people undergoing the brain surgery, but Corina's report and an in press paper, are the first detailed accounts of its effects on a deaf signer. "Although Broca's area has gotten considerable attention, its precise role in language behavior remains controversial," said Corina. "One controversy is whether Broca's areas is specialized just for speech or language in general. We have now been able to identify that Broca's area is involved in language production, not just speech production but any language spoken or signed. This is the best evidence that it is responsible for language independent of whether that language is expressed through the hands or the voice." Corina noted the surprising finding that stimulation to areas next Broca's area resulted in movements of the mouth and lips, but not the hands. "This study also strongly suggests that the supramarginal gyrus plays a critical role in blending semantic and phonetic information," he added, citing the word cat as an example. Cat has semantic features, being a "little furry critter that goes meow." It also has phonemic elements which correspond to the sound which make up the word cat --/k/ and /at/ in English -- and the hand shape and movements for a sign in American Sign Language. The supramarginal gyrus may be pulling together this kind of information, according to Corina. "Some people have wondered if the human brain has specialized areas of language production and processing," he said. "This work provides new evidence in favor of specialized areas of the brain which are unique to language processing and production. People also have asked if there is a so-called language organ. Our work suggests that there is a whole network of areas responsible for speech and language. Broca's area and the supramarginal gyrus are just two pieces of that network." The mapping procedure on S.T. lasted about 90 minutes prior to his surgery and was conducted while he was under a local anesthetic. The researchers tested a number of different left hemisphere sites for motor and language impairment by having S.T. do several tasks. He was shown pictures of 49 objects, such as a bird, chair, pig, bed and table, and asked to give the sign for each under normal conditions and while being electrically stimulated at each site. He also was asked to imitate signs and complex arm gestures. Only six sites showed any motor impairment and just two, Broca's area and the supramarginal gyrus, exhibited consistent impairments to language processing or production. Corina said basic research such as this is important because science is very interested in being able to provide people with improved communications skills. "One way to improve communications is to discover all the sub parts that are involved in language. To do this, we need to understand where and what portions of the brain are involved so we can develop better interventions to assist people," he said. "This work also has a practical application to help deaf people who, like hearing people, have seizures. The medical community needs to be aware that it can use the same standardized mapping procedures used on hearing people to identify language areas to ensure better post-operative outcomes on deaf patients. People need to realize that sign languages are real and naturally occurring human languages." Other members of the UW research team that mapped S.T.'s brain included George Ojemann and Carl Dodrill, professors of neurological surgery; James Brinkley, research associate professor of biological structure; Susan McBurney, doctoral student in linguistics, and Kevin Hinshaw, doctoral student in computer science and engineering.

Same Parts Of Brain Move Eyes And Shift Attention St. Louis-- If you've ever tried to sneak a peak at someone without them knowing, you may be surprised to learn that the parts of the brain that control eye movements are the same as those that shift attention. Unlike a camera, which records everything it sees, the brain can focus on one part of an image, as when you look into someone's eyes and ignore their other facial features. Scientists call this 'visual attention.' "The relationship of visual attention to eye movements is controversial," says Maurizio Corbetta, M.D., assistant professor of neurology, radiology and neurobiology at Washington University School of Medicine in St. Louis. "Behavioral data suggest that you can keep your eyes very steady while moving your attention around, so some people have predicted that different parts of the brain are used in the two tasks. But other behavioral data suggest that the two processes are functionally linked. Our imaging data demonstrate that visual attention and eye movement systems share the same areas of the brain and probably use similar neural mechanisms." Corbetta and colleagues determined which parts of the brain became active when subjects fixed their gaze on a particular spot but paid attention to their peripheral field of vision. They also imaged the brain while the subjects moved their eyes across their field of view. Therefore they were able to directly compare attention shifts with eye movements. They used functional magnetic resonance imaging to obtain the images. Lying in the scanner, six volunteers viewed a row of boxes on a computer screen. In the 'shifting attention' task, they fixed their gaze on the center of the display while shifting their attention to each of the boxes left of center to detect a visual stimulus ( a star ) in a box. In the 'eye movement' task, the subjects moved their eyes sequentially from one box to another, center to left, to detect the star. The images revealed which parts of the brain were active during each task. To get a better view, the researchers superimposed the data on flattened maps of the brain. Made by David C. Van Essen, Ph.D., the Edison Professor of Neurobiology and head of anatomy and neurobiology, and Heather A. Drury, research scientist of neurobiology, these 2-D maps show regions of the brain that normally are hidden in folds of tissue. The researchers mapped regions that became active during the 'shifting attention' task in red. They mapped regions that became active during the 'eye movement' task in green. Then they superimposed the two maps to show the common areas in yellow. Surprisingly, 60 percent to 80 percent of the activated regions were yellow. They were in the frontal, parietal and temporal lobes of the brain. "Such a tight overlap between attention and eye movements was a little surprising," says Gordon L. Shulman, Ph.D., research scientist of neurology and psychology. "It suggests that common processes are involved in moving the eyes and shifting attention." In light of this finding, Corbetta speculates that eye movements and attention may not have been independent in early mammals. "But in primates, there may have been the need to segregate direction of gaze from attention in space. That would allow you, for example, to pay attention to the dominant male in your group without looking directly at him." Corbetta M, Akbudak E, Conturo TE, Snyder AZ, Ollinger JM, Drury HA, Linenweber MR, Petersen SE, Raichle ME, Van Essen DC, Shulman GL. A common network of functional areas for attention and eye movements. Grants from the NIH, NASA and the Charles A. Dana Foundation supported this study.

Imaging the medial temporal lobe: exploring new dimensions. Brewer JB, Moghekar A. Dept of Neurology, Johns Hopkins Medical Institute Cognitive scientists have used developments in functional imaging to explore the role of the medial temporal lobe (MTL) in memory formation. Lesion studies have suggested that separate MTL subregions make distinct contributions to memory. Functional imaging of these distinct contributions, however, remains a challenge, because the proximity of the MTL substructures tests the spatial resolution limits of current techniques. Recent findings using electrophysiological measures of neural activity highlight the importance of using information from other imaging modalities. Integrating the different modalities of neuroimaging with lesion studies, and, further, combining modalities within experiments, will provide new insights into the function of MTL subregions. Comparison between simultaneously recorded amplitude integrated electroencephalogram (cerebral function monitor) and standard electroencephalogram in neonates. Pediatrics 2002 May;109(5):772-9 Toet MC, Van Der Meij W, De Vries LS, Uiterwaal CS, Van Huffelen KC. Department of Neonatology, Utrecht, the Netherlands. Department of Clinical Neurophysiology, Utrecht, the Netherlands. Julius Center for Patient Oriented Research, Utrecht, the Netherlands. OBJECTIVE: To assess the value and the limitations of amplitude integrated electroencephalogram (EEG) using the cerebral function monitor (CFM) in comparison with standard EEG in neonates who have hypoxic ischemic encephalopathy or were suspected of having convulsions. METHODS: In 36 neonates with a gestational age >/=36 weeks, CFM and simultaneously recorded EEG traces were analyzed off-line and independently classified. CFM background activity: continuous normal voltage; continuous normal voltage, slightly discontinuous (DNV); burst-suppression (BS); continuous extremely low voltage; flat tracing. CFM epileptiform activity: suspected epileptic activity, single seizure (SS), repetitive seizures (RS), status epilepticus (SE). EEG background activity: normal, depressed, low voltage undifferentiated, excessive discontinuity, BS, no activity. Epileptiform activity: interictal unifocal, interictal multifocal, ictal unifocal, ictal multifocal, SE. RESULTS: A total of 33 traces were suitable for analysis. Interobserver agreement on background activity was reached in 31 cases (kappa = 0.92) for CFM and in 27 cases (kappa = 0.74) for EEG. There was full agreement on CFM ictal activity (RS, SS, or SE) and EEG ictal activity. A normal CFM (continuous normal voltage) corresponded with a normal or a depressed EEG in 90% of the cases. The positive predictive value for a severely abnormal CFM (BS, continuous extremely low voltage, flat tracing) to correspond with a severely abnormal EEG (excessive discontinuity, BS, low voltage undifferentiated, no activity) was 100% (negative predictive value, 80%; sensitivity, 76%; specificity, 100%). DNV (10) on CFM corresponded either with depressed (6) or excessive discontinuity (4) on EEG. Ictal activity on EEG corresponded with SS, RS, or SE on CFM in 8 cases (sensitivity, 80%; specificity, 100%; positive predictive value, 100%; negative predictive value, 92%). CONCLUSION: CFM is a reliable tool for monitoring both background patterns (especially normal and severely abnormal) and ictal activity. Certain focal, low amplitude, and very short periods of seizure discharges can be missed. We recommend using CFM as a monitoring device and performing intermittent standard EEG whenever there is any doubt about the classification of the CFM (ie, DNV pattern or suspected epileptiform activity).

Sensitivity To Gluten May Result In Neurological Dysfunction; Independent Of Symptoms Source:   American Academy Of Neurology (http://www.aan.com/) ST. PAUL, MN – You may have gluten sensitivity and not even know it, according to a study published in the April 23 issue of Neurology, the scientific journal of the American Academy of Neurology. Loss of coordination (ataxia) may result from gluten sensitivity. This disease is known as gluten ataxia. The study found that some patients might never experience the gastrointestinal symptoms that prompt them to seek treatment for the disorder. “Gluten ataxia is a common neurological manifestation of gluten sensitivity,” according to M. Hadjivassiliou, M.D., of the Royal Hallamshire Hospital, Sheffield, UK. “It remains unclear why some patients with gluten sensitivity present solely with neurological dysfunction when others present with gastrointentestinal symptoms (gluten sensitive enteropathy) or an itchy skin rash (dermatitis herpetiformis).” Although the cerebellum (the part of the brain responsible for coordination) and in particular the Purkinje cells (output neurons of the cerebellum) appear to be most susceptible to damage in patients with gluten ataxia, other areas of the brain are not spared. “We were interested to determine the mechanism by which Purkinje cells are damaged in gluten ataxia,” commented Hadjivassiliou. Study results show that patients with gluten ataxia have antibodies against Purkinje cells and also that antibodies against gluten (antigliadin antibodies) cross-react with Purkinje cells. “These results strengthen our contention that eliminating these antibodies through strict adherence to a gluten-free diet may have important therapeutic implications for patients with gluten ataxia,” concluded Hadjivassiliou. The study was supported by the Friedreich's Ataxia Group, UK, and the Telethon Foundation, Italy. The American Academy of Neurology, an association of 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. For more information about the American Academy of Neurology, visit its website at www.aan.com. The original news release can be found at http://www.aan.com/public/nrelease/041602_gluten.htm

"Mapping the Mind: The Secrets of the Human Brain and How It Works" by Joel Davis Provides an intriguing study of the complex workings of the human brain, based on the latest scientific research, discussing the mysteries of learning, language, and memory; the origins of the brain; and the ways in which it controls the body, emotions, thoughts, and the continuing influx of data.

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