MRI technology reveals differences in neuro-signaling NEW YORK— Children with attention deficit-hyperactivity disorder (ADHD) may have significantly altered levels of important neurotransmitters (biochemicals that carry signals to and from cells) in the frontal region of the brain, according to a study publishing in the December issue of the Journal of Neuropsychiatry and Clinical Neurosciences. "Our data show children with ADHD had a two-and-half-fold increased level of glutamate, an excitatory brain chemical that can be toxic to nerve cells," said lead author Helen Courvoisie, M.D., assistant professor, division of child and adolescent psychiatry, department of psychiatry and behavioral sciences at the Johns Hopkins Medical Institutions, Baltimore. "The data also suggest a decreased level of GABA, a neuro-inhibitor. This combination may explain the behavior of children with poor impulse control." Dr. Courvoisie spoke today at an American Medical Association media briefing on advances in neurology in New York. "Children with ADHD have problems that are associated with the part of the brain called the frontal lobes," said Dr. Courvoisie. "The frontal lobes are like the 'boss of the brain,' responsible for what we call executive functioning — telling the brain and body what to do." This area regulates impulse control, attention, movement and elaborating on thoughts.

Keyword: ADHD
Link ID: 4646 - Posted: 06.24.2010

Study finds low to moderate alcohol use does not lower stroke risk A study by researchers at the Johns Hopkins Bloomberg School of Public Health and other institutions found a link between low to moderate alcohol consumption and a decrease in the brain size of middle-aged adults. Brain atrophy is associated with impaired cognition and motor functions. The researchers also found that low or moderate consumption did not reduce the risk of stroke, which contradicts the findings of some previous studies. The study is published in the rapid access edition of Stroke: The Journal of the American Heart Association. "Previous studies conducted with older adults found an association between heavy drinking, brain atrophy and an increased risk for stroke. We studied a younger, middle-aged population and found that low amounts of alcohol consumption are also associated with decreases in brain size," said Jingzhong Ding, PhD, lead author of the study and a research associate in the Department of Epidemiology at the School of Public Health. "Our findings do not support the hypothesis that low or moderate alcohol intake offers any protection against cerebral abnormalities or the risk of stroke in middle-aged adults."

Keyword: Drug Abuse
Link ID: 4645 - Posted: 12.05.2003

By Dr David Whitehouse, BBC News Online science editor Scientists have described their first complete design of an implant that will take the place of light-sensitive cells in the retina of a damaged eye. Current implants use chips that convert light into electrical impulses that are fed to the brain via the optic nerve. The new device will work differently. It will be placed on a damaged retina and convert light into chemicals that will stimulate nerve cells. The prototype is being constructed at Stanford University in California. Dr Stacey Bent of Stanford University calls the device "the holy grail of prostheses". It takes a new approach to replacing a damaged retina, the layer of cells at the back of the eye that detect light and send signals to the brain. Trauma or disease can damage or destroy retinal cells. Over the past few years implants have been developed to replace them based on electronic chips that turn light into electrical pulses. (C) BBC

Keyword: Vision; Robotics
Link ID: 4644 - Posted: 12.04.2003

NewScientist.com news service Alarm sirens intended to scare highly endangered whales away from ships that often kill them may actually be more likely to cause a collision, suggests new research. North Atlantic right whales are on the brink of extinction, with only 300 left despite being protected from whaling since 1935. The biggest risk to them now is collisions with ships. "Even if one individual is killed – it can be significant," says Douglas Nowacek who led the study at the Woods Hole Oceanographic Institution in Massachusetts. Understanding how whales respond to the sounds of ships is also important because many other whale species die in collisions. © Copyright Reed Business Information Ltd.

Keyword: Hearing; Animal Communication
Link ID: 4643 - Posted: 06.24.2010

Humour tickles drug centre that gives hedonistic high HELEN PEARSON There's truth in the maxim 'laughter is a drug'. A comic cartoon fired up the same brain centre as a shot of cocaine, researchers are reporting. A team at Stanford University in California asked lab mates, spouses and friends to select the wittiest newspaper cartoons from a portfolio. They showed the winning array to 16 volunteers while peering inside their heads by functional magnetic resonance imaging (fMRI). The cartoons activated the same reward circuits in the brain that are tickled by cocaine, money or a pretty face, the neuroscientists found1. One brain region in particular, the nucleus accumbens, lit up seconds after a rib-tickler but remained listless after a lacklustre cartoon. © Nature News Service / Macmillan Magazines Ltd 2003

Keyword: Brain imaging; Drug Abuse
Link ID: 4642 - Posted: 06.24.2010

CHICAGO – Malnutrition resulting from anorexia nervosa may cause emphysema, according to research presented today at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA). For the first time, researchers used a new method of assessing computed tomography (CT) scans to analyze the lungs of anorexic patients and found that malnutrition changes the physical structure of the lung. "There is a reduction in the amount of lung tissue in patients with anorexia nervosa," said Harvey O. Coxson, Ph.D., lead author of the study from Vancouver General Hospital (VGH) in Canada. "It is unclear whether these structural changes are permanent," he said, "but if they are, early therapy is important in patients who have anorexia." Dr. Coxson is an assistant professor of radiology at the University of British Columbia and an investigator at the Vancouver Coastal Health Research Institute at VGH and at the James Hogg iCAPTURE Centre for Cardiovascular and Pulmonary Research at St. Paul's Hospital in Vancouver.

Keyword: Anorexia & Bulimia
Link ID: 4641 - Posted: 06.24.2010

Many stress-related mental illnesses, including depression and post-traumatic stress disorder (PTSD), occur at least twice as often in women as in men. While social and cultural factors certainly may contribute to this statistic, potential neurobiological reasons for this discrepancy have been inadequately investigated. Depression and PTSD are characterized by dysfunction of an area of the brain called the prefrontal cortex (PFC), which is known to govern higher cognitive abilities like concentration and short-term memory. These functions have been shown in lab animals to be disrupted after exposure to stress. However, the experiments have largely been done only in male animals, and sex differences in how the PFC responds to stress are unknown. A better understanding of such processes may help to elucidate the reason that women are more susceptible to stress-related disorders, and lead to the development of better anti-depressant treatments. To examine the effects of stress on PFC function, male and female rats were exposed to different levels of mild stress, and then tested on a short-term memory task. The authors found that without stress, males and females performed equally well on the task. Likewise, after exposure to higher levels of stress, both males and females made significant memory errors. However, after exposure to a moderate level of stress, females were impaired, but males were not, suggesting that females were more sensitive to the PFC-impairing effects of stress. When the authors monitored the female rats' estrus cycles, they found that the rats showed this sensitivity only when they were in a high-estrogen phase.

Keyword: Stress; Hormones & Behavior
Link ID: 4640 - Posted: 12.04.2003

The causes and mechanisms of most brain diseases still evade scientists. A causal treatment exists for only few conditions. Therapeutic approaches at present aim predominantly at harm reduction. Harm reducing, brain function protecting measures are addressed with the term "neuroprotection". Neuroprotection is best defined as the effort to maintain / restore the highest possible integrity of cellular interactions in the brain, resulting in an overall undisturbed neural function. Neuroprotection is a novel approach for the treatment of schizophrenia. Over the last decade it has become clear that in addition to disturbed brain development, continuous neurodegenerative processes are involved in the progression of this brain disease. Nevertheless, molecular and cellular mechanisms accounting for the various dysfunctions of schizophrenic psychosis are far from clear. Existing animal models of schizophrenia only reflect certain aspects of the human disease. Therefore, novel concepts to treating schizophrenia should be immediately translated into clinical pilot trials. This is particularly appropriate if the beneficial compounds that are suggested are safe. During early episodes of schizophrenic psychosis, a dramatic worsening of cognitive performance is often observed.

Keyword: Schizophrenia; Hormones & Behavior
Link ID: 4639 - Posted: 12.04.2003

An unusual experiment with monkeys who were switched between mothers shortly after birth has demonstrated the importance of nature over nurture in behavior. Young monkeys reared by a mother other than their own are more likely to exhibit the aggressive or friendly behavior of their birth mothers rather than the behavior of their foster mothers, a University of Chicago researcher has shown for the first time. The discovery of inheritability of social behavior traits among non-human primates has important implications for people as it reinforces other research that suggests that such characteristics as sociability and impulsive aggressiveness among humans may have a genetic basis, said Dario Maestripieri, Associate Professor in Human Development at the University. The work with monkeys may help other researchers understand the biological origins of characteristics that promote socialization among humans, he said.

Keyword: Genes & Behavior; Aggression
Link ID: 4638 - Posted: 12.04.2003

(Bethesda, MD) – With the holidays come the traditions of sharing meals, desserts and treats with family, friends and co-workers. But the need to reduce the amount of food we consume daily – during the holiday season and throughout the year -- has acquired a greater sense of urgency in the wake of America’s obesity epidemic. As scientists look for ways to help us battle the bulge, a new study suggests that our own hormonal makeup may offer promising clues. A team of researchers has tested the hypothesis that gastric distension in humans can enhance the effect of cholecystokin (CCK) on the reduction of food intake. The researchers conclude that CCK's suppression of food intake is enhanced when the stomach is distended. CCK is a hormone released when digested fats and proteins are present, and reduces food intake. CCK stimulates enzyme secretion in the pancreas. The process eventually leads to inhibiting gastric emptying of the stomach’s foods, thereby causing gastric distension. It has been suggested that increased gastric distension, induced by slowing of gastric emptying, may be the method by which CCK reduces food intake.

Keyword: Obesity
Link ID: 4637 - Posted: 06.24.2010

Not to add to your stress level, but accumulating research indicates that continuous or intense stress may sometimes negatively influence the brain and its function. Studies find evidence that severe stress may sometimes alter brain cells, brain structure and brain function. As a consequence memory problems and the development of some mental diseases, including depression, may erupt. On the positive side, research also suggests that methods under investigation may be able to help ward off or even possibly reverse some of the stress effects. Tuesday it was tornadoes. Saturday, SARS. Today, terrorism. Increasingly worrisome headlines make the effort to understand how stress affects the brain take on a new level of importance. When we experience a stressful situation, our stress system activates a slew of biological mechanisms that boost our strength and energy, among other functions, to help us cope. Accumulating research, however, indicates that perpetual or intense stress sometimes may harm the brain and its function. These insights are leading to: Copyright © 2003 Society for Neuroscience

Keyword: Stress; Hormones & Behavior
Link ID: 4636 - Posted: 06.24.2010

CHICAGO – Sights and sounds cross paths abnormally in the minds of dyslexic readers, according to the first functional magnetic resonance imaging (fMRI) study of multisensory processing in people with the disorder. "Dyslexic readers appear to process auditory and visual sensory cues differently than do normal readers, and these differences may be the cause of their difficulty in reading," said the study's lead author, Jonathan H. Burdette, M.D., assistant professor of neuroradiology and associate in the department of bioengineering at Wake Forest University in Winston-Salem, N.C. Dr. Burdette presented his research today at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA). Dyslexia is a learning disability characterized by difficulty with word recognition. Up to 8 percent of American elementary school children may have the reading disorder, according to the National Institute of Mental Health. While the underlying neurological basis for dyslexia is still unclear, previous studies have shown that people with dyslexia cannot distinguish the sounds in spoken words. However, reading is a complex mental task, requiring a series of interactions among areas of the brain that control auditory, visual, language and memory processing.

Keyword: Dyslexia
Link ID: 4635 - Posted: 06.24.2010

CHICAGO – For the first time, researchers have used functional magnetic resonance imaging (fMRI) to investigate infant brain activity in response to speech and have found that, almost from birth, the brain's left hemisphere plays the leading role in processing most language functions. These preliminary findings, presented today at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA), challenge the previously held belief that left-hemisphere dominance isn't fully developed until puberty. "Language lateralization seems to be established almost from birth," said Shantanu Sinha, Ph.D., associate professor of radiology at the David Geffen School of Medicine at University of California Los Angeles, where the study is ongoing. Lateralization is the localization of a function, such as speech, to the right or left side of the brain. "To the best of our knowledge, this is the first time fMRI has been used to study infants," Dr. Sinha said. "Using fMRI, we can noninvasively study the neuronal response of newborns to stimulation of different kinds, without any ionizing radiation or pharmaceutical injections."

Keyword: Language; Laterality
Link ID: 4634 - Posted: 06.24.2010

ATLANTA – Researchers led by Jason Jaworski, PhD, and Michael Kuhar, PhD, both at the Yerkes National Primate Research Center at Emory University, have shown that CART peptide, a chemical that occurs naturally in both the rodent and human brain, reduces some effects of cocaine when additional amounts are administered to the region of the brain that is associated with reward and addiction. These findings, which were presented on November 8 at the Society for Neuroscience meeting in New Orleans, appear in the December issue of the Journal of Pharmacology and Experimental Therapeutics and suggest CART peptide receptors in the brain could be targets for developing medications to treat cocaine abuse. For their study, Dr. Jaworski, a post-doctoral fellow, and Dr. Kuhar, chief of the Neuroscience Division at Yerkes and a Georgia Research Alliance Eminent Scholar, infused CART peptide into the nucleus accumbens (NA) of rodents to determine how it affects the increase of body movement, or locomotor activity, that is widely seen as one effect of psychostimulant drugs. The researchers observed that the cocaine-induced movement was reduced after the rodents received CART peptide. "This is the first study to demonstrate CART peptides in the nucleus accumbens hinder the effects of cocaine," said Dr. Jaworski. "Our findings open a door to develop potential treatment options for cocaine addiction."

Keyword: Drug Abuse
Link ID: 4633 - Posted: 06.24.2010

Buck Institute researcher says findings may aid Alzheimer's fight David Perlman, Chronicle Science Editor Scientists seeking to restore brain function in patients with Alzheimer's disease have discovered that as the disorder slowly destroys the brain cells of the victims, new cells form that may provide a novel strategy for therapy. "This work is a long shot, but following up on long shots is what you have to do to make progress," said Dr. David A. Greenberg, a neurologist at the Buck Institute for Age Research in Novato. Greenberg is the senior researcher on a team of seven scientists who are publishing a report on their new Alzheimer's work in the current online issue of the Proceedings of the National Academy of Sciences. He is the first to concede that their findings have already raised more challenging questions than answers. ©2003 San Francisco Chronicle

Keyword: Alzheimers; Neurogenesis
Link ID: 4632 - Posted: 06.24.2010

Scientists claim to have found evidence that exercise may be physically addictive to some people. A study of mice found that when the exercise was denied to certain animals, brain scans revealed activity in areas normally linked to drug withdrawal. University of Wisconsin researchers suggested that the same might be true in "extreme" individuals who tended to exercise more heavily. Many experts believe that "exercise addiction" is not a physical condition. However, there is plenty of anecdotal evidence from frequent exercisers who report feelings of craving when they miss their regular exercise session. The study, published in the journal Behavioral Neuroscience, used a special breed of mice which, if given a running wheel to use, tend to use it for longer periods than ordinary mice. (C) BBC

Keyword: Drug Abuse; Muscles
Link ID: 4631 - Posted: 12.02.2003

There are new concerns about college students hitting the bottle instead of the books. As this ScienCentral News video reports, researchers say the problem could be bigger than previous studies indicated because the drinks are getting bigger. To most people, one beer is twelve ounces. But ask a college student to pour you a beer and you may get much more than you bargained for. "There's been an increase in a sort of heavy binge type drinking [among adolescents]," says Aaron White, assistant research professor of psychiatry at Duke University Medical Center and a research psychologist at the Durham Veterans Administration Medical Center. White says this may be partly due to the size of the drinks the students are pouring. © ScienCentral, 2000-2003.

Keyword: Drug Abuse
Link ID: 4630 - Posted: 06.24.2010

By MARY DUENWALD Sir Walter Scott was an author, not an evolutionary theorist. He wrote his poems and historical novels 40 years before Charles Darwin described the process of evolution — and well over a century before scientists began in earnest to apply principles of natural selection to the study of human nature. Yet Scott, a 19th-century writer, apparently shared with modern evolutionary scientists the general notion that men tend to follow two basic mating strategies. The new research is part of the fledgling field of Darwinian literary studies, in which scholars try to draw connections between literature and evolutionary science. Copyright 2003 The New York Times Company

Keyword: Sexual Behavior; Evolution
Link ID: 4629 - Posted: 06.24.2010

By DONALD G. McNEIL Jr. In September, the journal Science issued a startling retraction. A primate study it published in 2002, with heavy publicity, warned that the amount of the drug Ecstasy that a typical user consumes in a single night might cause permanent brain damage. It turned out that the $1.3 million study, led by Dr. George A. Ricaurte of Johns Hopkins University, had not used Ecstasy at all. His 10 squirrel monkeys and baboons had instead been injected with overdoses of methamphetamine, and two of them had died. The labels on two vials he bought in 2000, he said, were somehow switched. Copyright 2003 The New York Times Company

Keyword: Drug Abuse
Link ID: 4628 - Posted: 12.02.2003

CHICAGO – Using diffusion tensor imaging (DTI) to look into the brains of children with schizophrenia, researchers have discovered abnormalities in the white matter of the frontal lobe that disrupt the transmission of signals regulating behavior, according to a study presented today at the 89th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA). "Until now there's been no sophisticated method of finding abnormalities in the white matter of the brain," said the study's lead author Manzar Ashtari, Ph.D., associate professor of radiology and psychiatry at North Shore-Long Island Jewish Health System and Albert Einstein College of Medicine in New York. "Conventional magnetic resonance (MR) imaging is limited in its ability to reveal brain myelination, but DTI enables us to measure the myelination process." Myelin is the covering of nerve bundles that protects neurons and increases their transmission efficiency. The accumulation of myelin around these neurons is called myelination. In the human developmental process, myelination correlates with maturing patterns of behavior. In patients with schizophrenia, the cells that carry out the process of myelination are defective.

Keyword: Schizophrenia
Link ID: 4627 - Posted: 06.24.2010