by Dan Ferber Normal mice can walk across a narrow beam without falling, but mice with ALS symptoms take frequent tumbles. Transplanted human neuron-like cells helped ALS mice keep their motor skills longer than untreated mice. Two types of cell transplants hold off muscle atrophy in mouse models of amyotrophic lateral sclerosis (ALS). These results offer hope that cell transplants could one day be used to treat this devastating and incurable disease, two research groups announced here this week. ALS, also known as Lou Gehrig's disease, causes spinal-cord neurons that communicate with muscles to waste away, leading within five years to muscle weakness, then paralysis and death. Despite the efforts of researchers, there's little physicians can do for ALS patients; the only FDA-approved drug, sriluzole, prolongs life just six months. © Elsevier Science Limited 2000

Keyword: ALS-Lou Gehrig's Disease ; Regeneration
Link ID: 1056 - Posted: 11.27.2001

by Apoorva Mandavilli Several different teams today presented seemingly contradictory results on gender-specific differences in the response to stress. What is clear, however, is that much more research is needed to identify gender-specific differences and clarify the role of sex hormones in fostering them. Exposure to testosterone during gestation and development gives males an edge in learning while under stress, scientists from Rutgers University reported today. At the same time, German researchers point to an anti-stress role for the female hormone estradiol, and suggest women are less susceptible than men to acute stress. "Some of the results seem to be contradictory but they're really not," said Bruce McEwen, professor of neuroendocrinology at Rockefeller University, who moderated the session. The results differ because "depending on the particular situation and hormonal response, the response is different." © Elsevier Science Limited 2000

Keyword: Stress; Hormones & Behavior
Link ID: 1055 - Posted: 11.27.2001

by Dan Ferber New brain-imaging studies have pinpointed a brain region that helps us grasp mirror images and use them to direct our movement, according to results presented here Monday. The results shed light on how the brain makes sense of information from the space around us. Several years ago, doctors identified a subtle new brain defect in certain patients after a stroke. Patients with so-called mirror agnosia can see an object such as a ball in a mirror, recognize it, and identify it. But when asked to grab the ball, they reach toward the virtual object in the mirror and bump into the mirror, or try to reach around it, says Andrew Butler of Emory University School of Medicine. © Elsevier Science Limited 2000

Keyword: Vision; Stroke
Link ID: 1054 - Posted: 11.27.2001

by Apoorva Mandavilli The miracle drug L-dopa, which has been prescribed for Parkinson's disease (PD) patients for more than 30 years, may itself be partly responsible for the cognitive deficits associated with PD, three independent teams of researchers reported today. PD patients are also impaired at "habit" learning, which depends on the basal ganglia, the part of the brain that is affected by the disease. In addition to severe motor problems, scientists have identified PD-associated affective and cognitive defects, which can ultimately lead to a type of dementia. The cognitive aspects are very different from those seen in patients with Alzheimer's disease (AD), however. Rutgers University neuroscientist Mark Gluck and his colleagues developed computational models for brain simulation, which distinguish between PD and AD defects. AD patients with hippocampal damage have no trouble with simple associations between cues but have trouble transferring that knowledge to a novel task, for example. In contrast, PD patients are slow to learn, but once they master the associations, can apply their knowledge in novel situations. © Elsevier Science Limited 2000

Keyword: Parkinsons
Link ID: 1053 - Posted: 11.27.2001

by Dan Ferber Mice that can't make a peptide hormone called oxytocin can't recognize other mice by smell, so they keep on sniffing them. We can recognize a friend across a crowded room by sight, but mouse pals have to get close and start sniffing. New research, presented here today at a session on olfactory memory, has revealed a key brain hormone that helps them file these socially important odors in their memory banks. Larry Young of Emory University stumbled into the olfactory field accidentally when he and his colleagues were studying mice to uncover the neural basis for social disabilities seen in autism. It turned out that a line of mice lacking a small peptide hormone called oxytocin were socially at a loss, just like conference-goers who find a long-lost colleague but realize they have forgotten his name. Or worse. "They absolutely failed to recognize any individuals they'd seen before," Young says. © Elsevier Science Limited 2000

Keyword: Chemical Senses (Smell & Taste)
Link ID: 1052 - Posted: 11.27.2001

by Roberta Friedman Studies of the genes and signal molecules that govern how a fly's eye develops are leading scientists to the first hints of how the brain is wired. Fruit fly investigator Larry Zipursky of the University of California, Los Angeles, showed how alternative splicing of a newly characterized signal molecule may provide the required diversity to guide the complex wiring of the adult brain. The new focus of Zipursky's research is DSCAM, a receptor first identified in Downs syndrome (the abbreviation stands for Down's Syndrome cell adhesion molecule). Fruit flies have the molecule too, and it appears to help developing neurons find their way to target connections. New, preliminary information shows that DSCAM is localized in the nerve processes and not in the cell bodies, in areas of the fly brain relating to learning, smell, and sight. "It's highly expressed at times of targeting," Zipursky says. © Elsevier Science Limited 2000

Keyword: Development of the Brain
Link ID: 1051 - Posted: 11.27.2001

by Roberta Friedman Research presented here is beginning to reveal the molecular signals that guide the assembly of the brain, and that perhaps can be tapped into for making repairs. The glial cells that most neuroscientists have regarded as merely support cells in fact take an active role in building a brain. A primitive type of glial cell serves as the stem cells that actually generate the brain's neurons. Even in adults, these glial cells can form new neurons, scientists are finding. Evidence presented in a symposium supports the idea that the radial glial cells are actually the stem cells that give rise to neurons, and are not just directing their migration passively. Magdalena Götz and colleagues at the Max-Plank Institute of Neurobiology find that a transcription factor, Pax6, is used in the radial glial cells that are forming neurons. © Elsevier Science Limited 2000

Keyword: Glia; Neurogenesis
Link ID: 1050 - Posted: 06.24.2010

by Dan Ferber In the depths of the brain, hundreds of genes direct the workings of billions of neurons, which in turn direct the circuits that make us who we are. While some of those genes have been uncovered, hundreds remain unknown. By dissecting neurons and screening for active genes, new research is starting to reveal how dendrites, the signal-receiving end of neurons, go awry to cause diseases such as Fragile X mental retardation. All brain cells collect signals via the branched extensions called dendrites and pass them on via an axon. But beyond the dozens of types of neurons, the detailed patterns of dendrites are as diverse as the trees in a forest. What's more, dendrite malfunction appears to underlie an array of brain disease or injury, including schizophrenia, autism, traumatic brain injury, and fragile X mental retardation. For example, neurons from the hippocampus of mice with fragile X syndrome have more projections called dendritic spines, and the spines are longer and more immature, says James Eberwine of the University of Pennsylvania. © Elsevier Science Limited 2000

Keyword: Development of the Brain; Genes & Behavior
Link ID: 1049 - Posted: 11.27.2001

by Dan Ferber When subjects lie, the anterior cingulate cortex (top center, yellow) gets to work in the brains of almost all subjects. The images represent the brain seen from the top as if it had been sliced horizontally. Researchers have pinpointed a brain region that goes to work when we tell lies, and several other regions that help us read other people's intentions, according to work presented here today. In each case, the brain science validates a doctrine early philosophers and theorists posited about how we think. Polygraph tests measure physiological signs of anxiety, but they're notoriously unreliable, because liars can be calm and truthtellers can be anxious. To get to the root of lying behavior, Daniel Langleben's team at the University of Pennsylvania used a brain-imaging technique called event-related functional magnetic resonance imaging (fMRI) to find out which regions of the brain became metabolically active when a person lies. © Elsevier Science Limited 2000

Keyword: Stress
Link ID: 1048 - Posted: 11.27.2001

by Apoorva Mandavilli Neural stem cells (NSCs) can alleviate neural degeneration by instructing host cells to regenerate, rather than by maturing into neurons themselves, Harvard neurologist Evan Snyder said today. In mice with Purkinje cell (PC) degeneration, Snyder reports, NSCs may be reconstituting the PC layer either by protecting host cells or by stimulating a more vigorous regenerative response. "We think this may be the donor cells secreting things that change the host," Snyder said. "And this may apply not just to NSCs but to many other types [of stem cells]." In fact, he suggests, the new model may explain some functional results now observed in other stem cell experiments. Snyder and his colleagues transplanted donor NSCs into the cerebella of nervous (nr), Purkinje-cell-deficient (pcd), and lurcher (lc) mice with rapid degeneration of PCs. Transplanted NSCs dispersed broadly, but only a minority of them matured into neurons and glial cells, the researchers say. © Elsevier Science Limited 2000

Keyword: Stem Cells
Link ID: 1047 - Posted: 11.27.2001

by Roberta Friedman Nobel laureate Paul Greengard, addressing a packed hall at this meeting of some 28,000 neuroscientists, detailed the inner cascade of signals within a nerve cell that converges on one tiny protein. Greengard is convinced that drug companies can cash in on what we know about this key signal molecule, dubbed DARPP-32. By intelligently targeting new drugs to interfere at various points in the web of inner messages converging on DARPP-32, new therapeutics could act simply by changing the balance that determines whether DARPP-32 is sporting a phosphate molecule, or not. DARPP-32, a 32-kiloDalton-weight molecule first discovered to respond to the neurotransmitter dopamine, is the end result of some thirty years of work by Greengard (who received the 2000 Nobel Prize in physiology and medicine) and others. Seeking to understand how the arrival of a transmitter molecule such as dopamine across the synapse alters brain cell chemistry, researchers have found that all of the signals generated inside the recipient cell funnel through this one molecule. © Elsevier Science Limited 2000

Keyword: Miscellaneous
Link ID: 1046 - Posted: 11.27.2001

by Apoorva Mandavilli Why do individuals have different emotional responses to the same situation? University of Michigan researchers today report that cortical molecules of the stress system play a critical role in shaping individual differences in emotional reactivity. Specifically, increased expression of the glucocorticoid receptor, previously linked to learning and memory, is associated with increased anxiety, said Huda Akil, co-director of the university's Mental Health Research Institute. Using microarrays, Akil and her colleagues are now trying to identify other genes that are important in emotional response. "The brain is where genes and the environment meet to make us emotionally different," Akil said. Investigating brain circuits therefore has profound implications for understanding emotional behavior, and the causes of vulnerability to depression and anxiety disorders. © Elsevier Science Limited 2000

Keyword: Stress; Genes & Behavior
Link ID: 1045 - Posted: 11.27.2001

by Debra A. Titone Language is so frequently touted as the most ?human? of human capacities that I fear we, as a species, have overlooked that which truly distinguishes us from the rest of the natural world - dream interpretation. Early interpretation focused on the divine and often prophetic quality of dreams, guiding ancient humans to create art, world religions and military campaigns. Following the age of reason, dream interpretation took a back seat to scientific objectivity, and dreams were attributed to such things as indigestion, loud noise and anxiety (but see Freud for a later change of heart). Given this checkered past, it is not surprising that the modern study of dreams and the role of sleep in cognition is controversial. However, as detailed in a recent issue of Science, renewed efforts are enhancing our understanding of the role of dreams in the neural basis of such fundamental cognitive activities as memory consolidation. The dream-based memory consolidation hypothesis involves two main sleep stages, rapid eye movement (REM) and non-REM, which are associated with different patterns of neural activity, dreaming behavior and, when interrupted, deleterious effects on memory. © Elsevier Science Limited 2000

Keyword: Sleep; Learning & Memory
Link ID: 1044 - Posted: 11.27.2001

by Roberta Friedman Modern scans of the living human brain reveal a unique region that registers the inner state of the body. The insula, tucked inside the cortical covering of the brain, generates the uniquely human sense of self. The findings confirm concepts first presented by scholars of the nervous system a hundred years ago, and may give insight into syndromes of chronic pain. In a special lecture, neuroanatomist Arthur Craig of the Barrow Neurological Institute in Phoenix, Arizona, presented classic anatomic tracings, as well as cutting edge PET and fMRI scans, that delineate this insular cortex. An entire set of cerebral connections appears to have evolved in people that uniquely create a sense of self, Craig says. The messages start in the spinal cord, quite routinely. The first clue is found where these spinal inputs arrive at the brain's core, in the thalamus. © Elsevier Science Limited 2000

Keyword: Brain imaging; Attention
Link ID: 1043 - Posted: 11.27.2001

by Apoorva Mandavilli The much-celebrated amyloid vaccine approach in Alzheimer's disease (AD) is unlikely to reverse cognitive deficits in symptomatic patients, University of South Florida (USF) researchers cautioned today. Cognitive performance is indeed restored, if only the researchers wait long enough, countered a second team. The presentations, attended by a veritable who's who in AD research and peppered with questions from rivaling teams, carried on the contentious tradition in the AD community, albeit in an overtly polite manner. In the end, Dale Schenk told BioMedNet News, "the [human] clinical trials will tell." Elan Pharmaceuticals, where Schenk is vice president of discovery research, earlier this year began phase II clinical trials of the vaccine. The USF team has previously shown that APP/PS1 double-transgenic mice vaccinated at 8 months are protected from age-related cognitive impairment, as tested by a radial arm water maze. But at 18 months, immunization did not improve cognitive performance, says David Morgan, director of USF's Alzheimer's Research Laboratory. © Elsevier Science Limited 2000

Keyword: Alzheimers
Link ID: 1042 - Posted: 11.27.2001

by Kirsten C. Sadler Recent studies indicate that during apoptosis engulfing cells do not simply dispose of suicidal cells but actively participate in killing them. Even more striking is the observation that a small percentage of target cells may show some morphological signs of apoptosis but then apparently change their mind and return from the brink of death. Once a cell has received a death signal and makes the molecular decision to commit suicide, the killing is carried out in a stepwise fashion by, in most but not all cases, members of the Bcl-2 family, release of cytochrome c and other factors from the mitochondria and, in all cases, activation of the caspase family of proteases. Caspases dismantle the cell and also activate other proteases to aid in the execution. Once the deed is done, the dead cell's neighbors engulf the cell corpse. Some cells return from the brink of death. © Elsevier Science Limited 2000

Keyword: Apoptosis
Link ID: 1041 - Posted: 11.27.2001

(SAN DIEGO, Calif.) -- A new study coming out of UC Davis Medical Center and the Center for Neuroscience shows how estrogen can protect brain cells against various insults that cause the mental deterioration seen in many ailments, including Alzheimer's disease. The study is among those specifically highlighted at Society for Neuroscience meeting in San Diego on November 14. "We found, for the first time, that the hippocampus, a brain structure involved in memory, which shrinks in Alzheimer's disease patients, was larger in postmenopausal women who were taking estrogen replacement therapy than in either postmenopausal women who were not taking estrogen or a group of elderly men," says William Jagust, of the University of California in Davis. "Our results support the idea that estrogen replacement therapy protects brain cells and reduces the risk of developing Alzheimer's disease in postmenopausal women." In the study the researchers examined the brains of 59 postmenopausal women and 38 elderly men. Some of the subjects had mild memory problems but none met the criteria for a diagnosis of Alzheimer's disease. The brain imaging technique, magnetic resonance imaging (MRI), which provides a three-dimensional picture of the living brain, determined the size of each subject's hippocampus. The hippocampus was larger in the women taking estrogen than in the women not taking estrogen and the men.

Keyword: Hormones & Behavior; Alzheimers
Link ID: 1039 - Posted: 11.26.2001

Newts grow new legs, Hydra new heads. These remarkable creatures may hold clues for researchers developing human cellular therapies. But the connections are only now starting to be made. HELEN PEARSON Take one flatworm, chop into 279 pieces and leave for two weeks. Feed occasionally. The result: 279 perfect new worms. The ability of flatworms, or planarians, to regrow an entire body from a handful of cells seems almost miraculous. Salamanders, starfish, tentacle-waving polyps and zebrafish - many and varied are the organisms that can regenerate new heads, limbs, internal organs or other body parts if the originals are lost or damaged. Unfortunately, people cannot. But over the past few years, researchers studying regenerating creatures have begun to identify the genes, proteins and signalling pathways that underlie these organisms' abilities. This work indicates that the gulf between us and them is not so great. "We have the genes planarians use to regenerate their brain, muscle, their entire head," says Alejandro Sanchez Alvarado of the University of Utah in Salt Lake City. © Nature News Service / Macmillan Magazines Ltd 2001

Keyword: Regeneration
Link ID: 1038 - Posted: 11.26.2001

By Rachel Robertson Why would two Emory professors be showing sexually arousing pictures to subjects? For science, of course. Stephan Hamann and Kim Wallen, along with psychology graduate student Rebecca Herman, are collaborating on a project to study neural responses to visual sexual stimuli. In order to do this, they use Functional Magnetic Resonance Imaging (FMRI), a technique for measuring brain activation using an MRI scanner. This technique capitalizes on the fact that increased neural activity requires increased blood flow; changes in blood flow show up on the FMRI scans. Wallen, professor of psychology, brings to the project his knowledge of the neurobiology of nonhuman primates, especially the mechanisms involved in female sexual behavior. Wallen was interested in how that information can be brought to bear on what is known about humans.

Keyword: Sexual Behavior; Brain imaging
Link ID: 1037 - Posted: 11.26.2001

Learn how genetics could play a role in addiction By Eric Haseltine Over 2000 years ago, the Greek scholar Plutarch said "Drunks beget drunkards." Modern research shows that Plutarch knew what he was talking about. Children of substance abusers are up to 5 times more likely than offspring of "normal" parents to have problems with dependency or addiction sometime in their lives. Individuals prone to drug and alcohol addiction may be born with a paucity of receptors sensitive to the neurotransmitter dopamine in a part of the brain called the nucleus accumbens. Release of dopamine in this nucleus is believed to produce feelings of pleasure in response to normal healthy behaviors such as eating and procreating, but recent research suggests that substance abusers, born with too few dopamine receptors, cannot experience normal pleasures without taking chemicals that stimulate excess dopamine release. © Copyright 2001 The Walt Disney Company.

Keyword: Drug Abuse; Genes & Behavior
Link ID: 1036 - Posted: 06.24.2010