SAN DIEGO--Doctors who treat patients with posttraumatic stress disorder (PTSD) have long sought a therapy that would erase bad memories, or at least keep them in check. Preliminary research on rats and humans presented here 24 October at the meeting of the Society for Neuroscience suggests that a drug already in wide use for treating high blood pressure might have just that effect. The drug, propranolol, blocks certain receptors for the neurotransmitter norepinephrine and has already shown promise in small clinical trials for PTSD, apparently preventing the formation of traumatic memories. In those studies, emergency room patients given propranolol within a few hours after an accident had fewer symptoms of posttraumatic stress months later. That suggested that propranolol could act as a prophylactic. The new work hints that propranolol might also work on memories that have already formed. Jacek Dêbiec, a neurobiologist at New York University, conditioned rats to fear a tone by pairing it with a mild shock. After training, the rats freeze up in anticipation when they hear the tone. The next day, Dêbiec refreshed the rats' memory, exposing them again to the tone and shock. He then gave half of the animals an injection of propranolol. Two days later, untreated rats still remembered what the tone meant; upon hearing it, they froze about 70% of the time. But rats given propranolol froze only about half as often, indicating a weaker memory for the fearful association between sound and shock. Even when Dêbiec waited 2 months before reactivating the memory and delivering propranolol, the drug had a similar effect, he reported at the meeting and in a paper published in the current issue of Neuroscience. Copyright © 2004 by the American Association for the Advancement of Science.

Keyword: Learning & Memory; Emotions
Link ID: 6316 - Posted: 06.24.2010

EUGENE, Ore. -- A trusted mental map of your surroundings turns out to be slightly misaligned, skewing your orientation. Your ability to control the direction in which you move is similarly compromised, although in a manner opposite the map's offset. Taken together, the errors cancel one another, and you end up exactly where you want to be. Contrary to the proverb, two wrongs do make a right. This exception is the rule when it comes to how our brain processes what our eyes see and where our body moves, according to a discovery by University of Oregon researchers Paul Dassonville and Jagdeep Kaur Bala that will appear in the November issue of the journal PLoS Biology. Their study, funded by the National Science Foundation, challenged a dominant theory of how the brain processes vision. The theory holds that information from the eyes separates into two distinct streams: one to simply represent where we see things in the environment, and another to guide the physical movements of our body within that environment. Both processes have been thought to depend largely on accessing distinct maps of the environment within the brain, representing objects from varying locations in our field of vision by systematically varying activity in corresponding regions of the brain.

Keyword: Vision
Link ID: 6315 - Posted: 10.26.2004

by Rita Suri, M.D., and Lori L. Altshuler, M.D. Lifetime prevalence rates of major depressive disorder (MDD) in women are estimated to be as high as 21% (Kessler et al., 1993; Weissman et al., 1993). The postpartum period in particular represents a time of increased vulnerability for women (Cox et al., 1993; O'Hara et al., 1990), though postpartum disorders are often under-recognized and undertreated. Pregnant women generally receive little education about the possibility of depression after delivery, and because symptoms of depression can overlap with common postpartum symptoms, they may go unrecognized. Women may also feel ashamed of having negative emotions at a time when they "should be joyful" and thus not seek professional help. The DSM-IV defines postpartum depression as a major depressive episode with an onset in the first four weeks following childbirth. Although epidemiologic studies vary in the time frame used to define the postpartum period, ranging from four weeks to six months after delivery, the period of increased risk seems to occur relatively close to delivery. A study by Cox et al. (1993) of 232 postpartum women found that rates of depression were threefold higher in the five weeks after giving birth, but comparable at six months postpartum, when compared to a similarly matched control group of women who had not had a baby within the last 12 months. Wisner et al. (2004a) found that in 51 nondepressed women with a history of postpartum depression, 21 women developed a recurrent postpartum episode when followed for the year after childbirth. Five (24%) of these women experienced depression in the first postpartum month. © 2004 Psychiatric Times. All rights reserved.

Keyword: Depression; Hormones & Behavior
Link ID: 6314 - Posted: 06.24.2010

by Leo Sher, M.D. Light therapy, in one form or another, has been used as a treatment for a number of conditions since ancient times. Nearly 2,000 years ago, Greco-Roman physicians were treating depression and lethargy with sunlight directed toward the eyes. During his Arctic expeditions in the 1890s, Frederick Cook, M.D., noticing the profound influences of light on the voyagers and Alaskan natives, described a syndrome characterized by depressed mood, fatigue, and loss of energy and sexual desire. In 1946, H. Marx reported the use of bright artificial light to treat four men who had become depressed during an Arctic winter. Contemporary light therapy involves daily scheduled exposure to bright artificial light (Lam et al., 1999b; Partonen, 2001; Rosenthal and Matthews, 1999). The term light therapy is used to differentiate light therapy for psychiatric disorders from phototherapy for other conditions, such as hyperbilirubinemia or psoriasis. Since the first study of light therapy in winter seasonal affective disorder (SAD) (Rosenthal et al., 1984), a syndrome in which depression developed during fall or winter and remitted the following spring or summer for at least two successive years, numerous studies have concluded that bright light therapy is an effective treatment for SAD (Lam et al., 1999b; Magnusson and Boivin, 2003; Oren and Rosenthal, 1992; Partonen, 2001). © 2004 Psychiatric Times. All rights reserved.

Keyword: Depression; Biological Rhythms
Link ID: 6313 - Posted: 06.24.2010

by Richard C. Shelton, M.D. Currently available antidepressant medications are effective for a large segment of the population with depression. However, recent data suggest that a sizable portion of patients with unipolar depression do not experience full therapeutic recovery. For example, Simon et al. (1999) found that only about half of depressed patients treated with antidepressants in a primary care setting achieve recovery over a two-year period. Since lack of full response is common, management strategies need to be established and implemented. Current approaches include: the use of combination antidepressant treatments (e.g., selective serotonin reuptake inhibitor and bupropion [Wellbutrin]), augmentation (e.g., the addition of lithium [Eskalith, Lithobid] or thyroid hormone to an antidepressant), the addition of psychotherapy or electroconvulsive therapy (Shelton, 2003, 1999). However, even with these approaches, a significant minority of patients do not experience a full therapeutic effect. Recently, novel antipsychotics have shown some promise for the management of depressive disorders. From a mechanistic standpoint, the pharmacological properties of at least some of these drugs predict antidepressant properties. Novel antipsychotics act, to varying degrees, on a variety of dopamine, serotonin (5HT), glutamate and other receptors. The antagonism of 5HT2A receptors is common among these drugs, and blockade of this subtype is seen with other antidepressant agents such as mirtazapine (Remeron) and nefazodone (Serzone). Blocking of 5HT2C receptors has also been shown to enhance release of frontal dopamine and norepinephrine, which is thought to be a key antidepressant property (Shelton, 2003; Zhang et al., 2000). © 2004 Psychiatric Times. All rights reserved.

Keyword: Depression
Link ID: 6312 - Posted: 06.24.2010

SAN DIEGO – Students, keep this in mind before that next major exam: Pre-test jitters make it easier to recall memorized facts, but that stress also makes it tough to solve more complex problems. Researchers at Ohio State University gave a battery of simple cognitive tests to 19 first-year medical students one to two days before a regular classroom exam – a period when they would be highly stressed. Students were also given a similar battery of tests a week after the exam, when things were less hectic. While pre-exam stress helped students accurately recall a list of memorized numbers, they did less well on the tests that required them to consider many possibilities in order to come up with a reasonable answer. A week after the exam, the opposite was true. "Other studies have suggested that elevated stress levels can actually improve some aspects of cognition, particularly working memory," said Jessa Alexander, a study co-author and a research assistant in neurology at Ohio State. "The results of the two problem-solving tests we administered suggested a decline in problem solving abilities that required flexible thinking."

Keyword: Learning & Memory; Stress
Link ID: 6311 - Posted: 06.24.2010

Using an animal model system, researchers have advanced our understanding of Fragile X Syndrome by successfully visualizing individual mutant neurons in an otherwise normal brain. They find that brain neurons that fail to express appropriate levels of Fragile X protein are structurally abnormal and make defective connections to other neurons. The work is reported by a team led by Kendal Broadie at Vanderbilt University. Fragile X Syndrome is the most common type of inherited mental retardation. Since the early 1990's, it has been known that the disease results from the loss of a single gene and, for the last several years, that the Fragile X gene product regulates the expression of other proteins. However, the link between this molecular function and the Fragile X brain defect has remained a mystery. Employing a fruit fly model of the disease, the researchers utilized a new technique that allows the generation of single mutant nerve cells that are marked by their expression of a glowing fluorescent protein, making these nerve cells distinctly visible in an otherwise normal brain. In their experiments, the researchers were able to observe mutant nerve cells that either completely lacked the Fragile X protein or overexpressed it, the fluorescent protein label allowing the entire architecture of these neurons to be visualized in the intact brain.

Keyword: Genes & Behavior
Link ID: 6310 - Posted: 10.26.2004

The world’s first brain prosthesis has passed the first stages of live testing. The microchip, designed to model a part of the brain called the hippocampus, has been used successfully to replace a neural circuit in slices of rat brain tissue kept alive in a dish. The prosthesis will soon be ready for testing in animals. The device could ultimately be used to replace damaged brain tissue which may have been destroyed in an accident, during a stroke, or by neurodegenerative conditions such as Alzheimer’s disease. It is the first attempt to replace central brain regions dealing with cognitive functions such as learning or speech. To achieve their result, Theodore Berger and his colleagues at the University of Southern California in Los Angeles, US, had to develop a system that would “read” real neural signals from healthy tissue, process them just as the lost brain tissue should, and pass on the resulting signals to the next brain area. The brain region they are trying to replace is the hippocampus, which is vital for forming memories. The hippocampus has a well-understood three-part circuit. It also has a regular repeating structure, so elements of all three parts of the hippocampal circuit can be kept in a fully functional state, even in small slices in a culture dish. © Copyright Reed Business Information Ltd.

Keyword: Learning & Memory
Link ID: 6309 - Posted: 06.24.2010

SAN DIEGO – Researchers at the OHSU Oregon National Primate Research Center (ONPRC) have identified a key gene that impacts the timing of puberty and can shorten the time span for reproduction. The research was led by Sergio Ojeda, Ph.D., head of the Division of Neuroscience and a senior scientist at ONPRC. The work will be presented at the Society for Neuroscience annual meeting on Oct 24, 2004 by Claudio Mastronardi, the lead author of the report. "Using a mouse model, our lab has determined that the absence in the brain's hypothalamus of a gene called TTF-1 causes a delay in the onset of female puberty," explained Ojeda. "This work is of particular interest to those investigating both the delay and early onset of puberty in young women. While there is no definitive information, recently a number of research papers have been published suggesting that young women are reaching puberty at an earlier age. Other research has suggested that if this is the case, it may be linked to the nation's obesity crisis." Prior to the research to be reported at the Society for Neuroscience meeting, Ojeda's group performed studies with rats showing that the TTF-1 gene is expressed in a discrete cellular subset of the hypothalamus during sexual development. Then, using a genome-wide approach, they determined that expression of the TTF-1 gene increases in the hypothalamus of nonhuman primates at the onset of puberty.

Keyword: Hormones & Behavior; Obesity
Link ID: 6308 - Posted: 06.24.2010

Regular exercise could halt Parkinson's disease, US researchers believe. In a study on rats, exercise prevented degeneration of nerve cells that are normally destroyed by the disease. The University of Pittsburgh researchers are now recruiting patients to see if regular exercise has the same effect in humans. They told a meeting of the Society of Neuroscience how exercise might stimulate key proteins vital for nerve cell survival. In Parkinson's disease, cells in the brain that contain a messenger called dopamine progressively die out. This means messages don't get through in the normal way, which causes the tell-tale signs of the disease such as uncontrollable tremors, slow movements and rigid limbs. There is some disagreement within the Parkinson's research community as to the benefits of intense exercise for people with PD. While none have reported harm caused by physical activity, some studies have shown no statistical positive influence of exercise. Dr Michael Zigmond and colleagues examined the brains of rats that had exercised for seven days before receiving a toxin that is known to induce a disease resembling Parkinson's in rodents. They compared these animals to rats that had not been exercised before receiving the toxin. Exercise appeared to protect the brain against Parkinson's-type damage. Fewer dopamine-containing nerve cells, or neurons, died in the exercised rats compared to the sedentary rats. The researchers believe exercise stimulates the production of proteins that are important for the survival of neurons. (C)BBC

Keyword: Parkinsons
Link ID: 6307 - Posted: 10.25.2004

By MARC SANTORA The disease's fatal grip on the brain seems to come out of nowhere, afflicting an otherwise healthy person and turning him into an incoherent muddle. In Ulster County in upstate New York, that was how death came to at least two people in the last year. The rare brain malady called Creutzfeldt-Jakob disease caused the death of one resident in November 2003 and of a second this fall. About one in a million people worldwide die from the mysterious disease each year, and there is no medical explanation for why the disease afflicts humans in its most common form. There has been a recent buzz in Ulster County about the strange illness, but only within the small circles of the victims' families. Then the community discovered that a 60-year-old woman had died in August from an illness that seemed similar to Creutzfeldt-Jakob disease. The woman's family did not allow an autopsy, so it cannot be determined if she had the disease. But after comparing notes, people found out that another person in nearby Dutchess County died of the disease this year. There have been other unusual deaths, including that of another woman in Ulster County, Colleen Staccio, 46, who died in August from a condition her doctors initially said was Creutzfeldt-Jakob disease but whose autopsy showed otherwise, and that of Richard Tobey, 59, who died of the disease two weeks ago. Copyright 2004 The New York Times Company

Keyword: Prions
Link ID: 6306 - Posted: 10.25.2004

By Norman M. Weinberger Music surrounds us–and we wouldn't have it any other way. An exhilarating orchestral crescendo can bring tears to our eyes and send shivers down our spines. Background swells add emotive punch to movies and TV shows. Organists at ballgames bring us together, cheering, to our feet. Parents croon soothingly to infants. And our fondness has deep roots: we have been making music since the dawn of culture. More than 30,000 years ago early humans were already playing bone flutes, percussive instruments and jaw harps--and all known societies throughout the world have had music. Indeed, our appreciation appears to be innate. Infants as young as two months will turn toward consonant, or pleasant, sounds and away from dissonant ones. And when a symphony's denouement gives delicious chills, the same kinds of pleasure centers of the brain light up as they do when eating chocolate, having sex or taking cocaine. Therein lies an intriguing biological mystery: Why is music--universally beloved and uniquely powerful in its ability to wring emotions--so pervasive and important to us? Could its emergence have enhanced human survival somehow, such as by aiding courtship, as Geoffrey F. Miller of the University of New Mexico has proposed? Or did it originally help us by promoting social cohesion in groups that had grown too large for grooming, as suggested by Robin M. Dunbar of the University of Liverpool? On the other hand, to use the words of Harvard University's Steven Pinker, is music just "auditory cheesecake"--a happy accident of evolution that happens to tickle the brain's fancy? © 1996-2004 Scientific American, Inc.

Keyword: Hearing
Link ID: 6305 - Posted: 06.24.2010

Washington -- Researchers at the Boston Veterans Affairs Health Care System – Brockton Division, Harvard Medical School, and the University of Massachusetts-Boston are using new imaging technology to gather valuable information about the brains of people with schizophrenia. This new variety of magnetic resonance imaging (MRI) is called diffusion tensor imaging (DTI). Using DTI on patients with schizophrenia, neuropsychologists have related smaller sizes in two distinct webs of brain fibers to two distinct types of cognitive malfunction. The findings appear in the October issue of Neuropsychology, which is published by the American Psychological Association (APA). Diffusion tensor imaging (DTI) uses a regular MRI machine to analyze the movement of water molecules in and around the fibers that connect different parts of the brain. Neuroscientists use DTI to track indicators of brain "connectivity" – factors such as the number, thickness, density and arrangement of axons (the hair-like extensions of neurons, which send messages to other neurons) and thickness of the insulating/conducting fatty myelin sheath in which they are embedded. If weaker structural integrity reduces connectivity, lead author Paul Nestor, PhD, says it may mean that, "different brain areas do not communicate as well – with less synchrony or harmony, akin to an orchestra or band playing out of synch."

Keyword: Schizophrenia; Brain imaging
Link ID: 6304 - Posted: 06.24.2010

SAN DIEGO-- A repetitive drop in blood oxygen levels in newborn rats, similar to that caused by apnea (brief pauses in breathing) in some human infants, is followed by a long-lasting reduction in the release of the brain neurotransmitter dopamine, according to an Emory University research study. Because dopamine promotes attention, learning, memory and a variety of higher cognitive functions, the researchers believe repetitive apnea during neonatal development may be one factor leading to the development of attention deficit hyperactivity disorder (ADHD). This research will be reported at the Society for Neuroscience annual meeting in San Diego on October 24 by Glenda Keating, PhD, and Michael Decker, PhD, of the Department of Neurology at Emory University's School of Medicine. The research was funded by the National Heart Lung and Blood Institute and conducted by the Program in Sleep Medicine and the Department of Neurology at Emory University. Apnea of prematurity occurs in up to 85 percent of all prematurely born human infants, and obstructive sleep apnea occurs in 3 to 27 percent of all children. Data from previous studies suggests that diminished release of brain dopamine may be responsible for behaviors such as impulsiveness and distractibility, reduced self control, and impaired learning, which are hallmark traits associated with ADHD. Previous studies in Dr. Decker's laboratory at Emory have shown that newborn rats who experience repetitive drops in blood oxygen levels go on to develop behavioral traits similar to those seen in humans with ADHD. This is the first time, however, that researchers have linked repetitive reductions in blood oxygen levels during a period of critical brain development to long-lasting deficiencies in release of dopamine specifically within the striatum, which is one of the brain regions important in modulating behavior, learning and memory.

Keyword: ADHD
Link ID: 6303 - Posted: 10.25.2004

The weird and wonderful duck-billed platypus just got even more weird and more wonderful. Platypuses are famous for laying eggs yet producing milk, having a bird-like bill and a skeleton with reptilian features. Now it turns out that the mammal has an equally eye-catching way of deciding its sex, according to a study by Frank Grützner and Jenny Graves at the Australian National University in Canberra, and colleagues. In most mammals, including humans, sex is decided by the X and Y chromosomes: two Xs create a female, while XY creates a male. In birds, the system is similar: ZW makes for a female, while ZZ makes for a male. But in platypuses, XXXXXXXXXX creates a female, while XYXYXYXYXY creates a male. In other words, rather than a single chromosome pair, platypuses have ten-chromosome chains that determine their sex. The researchers worked out the make-up of platypus sex chromosomes by using fluorescent markers to stain chromosomes in platypus cells before examining them under a microscope. The researchers also found that when sperm is produced by male platypuses, the chromosomes in the chain are precisely distributed to form XXXXX-bearing sperm and YYYYY-bearing sperm. When an XXXXX-bearing sperm fertilises an egg it produces a female platypus. YYYYY-bearing sperm would produce a male. © Copyright Reed Business Information Ltd.

Keyword: Sexual Behavior; Evolution
Link ID: 6302 - Posted: 06.24.2010

St. Louis, -- Severe calorie restriction prevents certain aging-related changes in the brain, including the accumulation of free radicals and impairments in coordination and strength, according to a mouse study at Washington University School of Medicine in St. Louis. However, the dietary changes did not seem to prevent mice from developing some cognitive deficits associated with age, such as declines in memory. The study will be presented at 3 p.m. PT on Sunday, Oct. 24 at Neuroscience 2004, the Society for Neuroscience's 34th Annual Meeting in San Diego. "Our findings help us understand the processes underlying both normal aging and calorie restriction benefits," says principal investigator Laura L. Dugan, M.D., associate professor of neurology, of medicine and of anatomy and neurobiology. "If some aspects of aging are influenced by free radical damage, we may be able to prevent or reverse these impairments." Though numerous studies have shown severe calorie restriction helps animals live longer and resist some effects of aging, scientists still do not know why. One theory suggests a restrictive diet decreases the effect of free radical damage.

Keyword: Alzheimers; Obesity
Link ID: 6301 - Posted: 10.25.2004

By Jennifer Viegas, Discovery News A University of Florida scientist has created a living "brain" of cultured rat cells that now controls an F-22 fighter jet flight simulator. Scientists say the research could lead to tiny, brain-controlled prosthetic devices and unmanned airplanes flown by living computers. And if scientists can decipher the ground rules of how such neural networks function, the research also may result in novel computing systems that could tackle dangerous search-and-rescue jobs and perform bomb damage assessment without endangering humans. Additionally, the interaction of the cells within the lab-assembled brain also may allow scientists to better understand how the human brain works. The data may one day enable researchers to determine causes and possible non-invasive cures for neural disorders, such as epilepsy. For the recent project, Thomas DeMarse, a University of Florida professor of biomedical engineering, placed an electrode grid at the bottom of a glass dish and then covered the grid with rat neurons. The cells initially resembled individual grains of sand in liquid, but they soon extended microscopic lines toward each other, gradually forming a neural network — a brain — that DeMarse says is a "living computational device." Copyright © 2004 Discovery Communications Inc.

Keyword: Robotics
Link ID: 6300 - Posted: 06.24.2010

COLUMBUS, Ohio – Inebriated bees could give researchers better insight into alcohol's effects on human behavior, a new study suggests. "Alcohol affects bees and humans in similar ways – it impairs motor functioning along with learning and memory processing," said Julie Mustard, a study co-author and a postdoctoral researcher in entomology at Ohio State University. Researchers gave honey bees various levels of ethanol, the intoxicating agent in liquor, and monitored the ensuing behavioral effects of the drink – specifically how much time the bees spent flying, walking, standing still, grooming and flat on their backs, so drunk they couldn't stand up. The researchers also measured the level of ethanol in the bees' hemolymph – the circulatory fluid of insects that's akin to blood. Not surprisingly, increasing ethanol consumption meant bees spent less time flying, walking and grooming, and more time upside down. The appearance of inebriation occured sooner for bees that were given a larger dose of ethanol. Also, blood ethanol levels increased with time and the amount of ethanol consumed.

Keyword: Drug Abuse
Link ID: 6299 - Posted: 06.24.2010

Treating children with anti-psychotic drugs may increase the risk of a condition which leads to diabetes and heart disease, research suggests. A team from Johns Hopkins University looked at 'atypical' antipsychotics, used to treat behavioural problems such as manic depression and schizophrenia. They found their use may trigger insulin resistance. The research was presented to a meeting of the American Academy of Child and Adolescent Psychiatry. Considerable weight gain is a common side effect of atypical antipsychotic medications - and is also one of the many factors that can contribute to insulin resistance. All six children on moderate or high doses of one of these drugs, and three of five children on low doses, had evidence of insulin resistance. This is a condition in which the body cannot properly use the insulin it produces. Lead researcher Dr Mark Riddle said: "The insulin resistance seen in these children was greater than what would be expected from weight gain alone, suggesting there is a factor distinct from excess weight that directly induces insulin resistance." (C)BBC

Keyword: Schizophrenia; Development of the Brain
Link ID: 6298 - Posted: 10.23.2004

New Haven, Conn.--Estrogen treatment had less beneficial effect on memory in female mice that raced on running wheels and played with other toys than in mice raised in non-stimulating environments, according to a Yale study published this month. "We saw no beneficial effect of estrogen in the animals in cognitively and physically stimulating environments (also known as enriched environments)," said Karyn Frick, assistant professor of psychology and principal investigator on the study. "This fits in nicely with human data and might help to explain why studies of hormone replacement therapy (HRT) do not show beneficial effects for all women. Most studies of HRT use very well-educated women. These results might spur researchers to include a broader population with a greater variation in education and socioeconomic status." All of the mice lived in standard housing conditions that contained other mice and no toys. However, enriched mice spent three hours each day in larger cages with running wheels, tubes, and other mouse toys. The toys were varied from day to day. At 10 weeks of age, the ovaries of the mice were removed to simulate the long-term estrogen losses seen in menopause. At six months of age, the mice were then treated with estrogen or a control substance and were tested in tasks measuring spatial memory and memory for objects.

Keyword: Hormones & Behavior; Learning & Memory
Link ID: 6297 - Posted: 10.23.2004