Working memory (also known as short term memory) is our ability to keep a small amount of information active in our mind. This is useful for information we need to know on-the-fly, such as a phone number or the few items we need to pick up from the grocery store. We hang on to the information for a brief period of time, just long enough to make a phone call or get through the checkout line, and then we forget it forever.
We receive much of our information through our visual system, but it was unknown how much of this visual information is actively involved in short term memory. Psychologists John T. Serences from the University of California, San Diego, along with Edward F. Ester, Edward K. Vogel and Edward Awh from the University of Oregon wanted to examine which neural systems enable the maintenance of these visual details in short term memory.
We engage in numerous discussions throughout the day, about a variety of topics, from work assignments to the Super Bowl to what we are having for dinner that evening. We effortlessly move from conversation to conversation, probably not thinking twice about our brain's ability to understand everything that is being said to us. How does the brain turn seemingly random sounds and letters into sentences with clear meaning?
In a new report in Current Directions in Psychological Science, a journal of the Association for Psychological Science, psychologist Jos J.A. Van Berkum from the Max Planck Institute in The Netherlands describes recent experiments using brain waves to understand how we are able to make sense of sentences.
In these experiments, Van Berkum and his colleagues examined Event Related Potentials (or ERPs) as people read or heard critical sentences as part of a longer text, or placed in some other type of context. ERPs are changes in brain activity that occur when we hear a certain stimulus, such as a tone or a word. Due to their speed, ERPs are useful for detecting the incredibly fast processes involved in understanding language.
Analysis of the ERPs has consistently indicated just how quickly the brain is able to relate unfolding sentences to earlier ones. For example, Van Berkum and colleagues have shown that listeners only need a fraction of a second to determine that a word is out of place, given what the wider story is about. As soon as listeners hear an unexpected word, their brain generates a specific ERP, the N400 effect (so named because it is a negative deflection peaking around 400 milliseconds). And even more interesting, this ERP will usually occur before the word is even finished being spoken.
Patients' offspring have memory loss
Children of parents with Alzheimer's disease can develop memory problems in their 50s or even younger - much earlier than previously thought - according to a large study released yesterday by researchers at Boston University School of Medicine.
The study subjects, who carried a gene strongly linked to Alzheimer's, performed worse in memory tests, on average, than other middle-aged people who had the same gene but did not have a parent diagnosed with Alzheimer's. The difference in memory between the two groups was equivalent to approximately 15 years of brain aging, researchers found.
"How big an effect we saw was surprising," said Dr. Sudha Seshadri, a BU associate professor of neurology and senior author of the study. "It was like you were comparing two groups, 55-year-olds to 70-year-olds."
Young adults showing signs of suffering a stroke are being misdiagnosed in hospital emergency rooms and women are less likely than men to receive a blood thinning drug that can limit brain damage after a stroke, according to separate studies by Michigan universities.
The studies were presented this week in San Diego at the International Stroke Conference, organized by the American Heart Association and American Stroke Association.
Most testing for the U.S. drug industry's late-stage human trials is now done at sites outside the country, where results often can be obtained cheaper and faster, according to a study.
The study found that 13,521 of 24,206 sites being used in November 2007 for studies sponsored by the 20 largest U.S. drug makers were international, and that the number of countries conducting testing has doubled over the past 10 years. The study was published in Wednesday's New England Journal of Medicine.
The findings add to concerns about the ethical treatment of participants and the integrity of the research data produced in developing countries. Experts also say patients in developing countries may be taken advantage of because they are poorer and less familiar with the research process.
Inflammatory diseases like rheumatoid arthritis cause fatigue because white blood cells -- monocytes -- infiltrate the brain, Canadian researchers said.
Senior author Dr. Mark Swain of the University of Calgary and colleagues found that in mice with inflamed livers monocytes infiltrated the brain. These findings support previous research demonstrating the presence of immune cells in the brain following organ inflammation, challenging the long-held belief that the blood-brain barrier prevents immune cells from accessing the brain.
Premature birth occurs to more than half a million babies in the United States each year, often for reasons not yet understood. The earlier in pregnancy a baby is born, the more health problems it is likely to have. Babies who are born extremely preterm, prior to 28 weeks gestation, are at high risk for breathing problems, brain damage, and digestive problems in the first few days of life, but they are also at risk for a wide range of lifelong health challenges in the form of cerebral palsy, hearing and vision loss, and learning and developmental delays. There is also mounting evidence that babies born more than three months early face a much higher risk of developing autism compared to babies born full-term.
Another study has confirmed the link between abortion and subsequent premature births when a woman is pregnant again. Previous studies have substantiated the link and now new research involving more than one million births show abortion is responsible for elevating pre-term birth risk.
Dr. Manfred Voigt led the new study, published in the German medical magazine Z Geburtshilfe Neonatol late last year.
Social networking sites may be harmful to your health, an expert claims.
Dr. Aric Sigman says Web sites - such as Facebook and Myspace - are meant to easily connect people, strengthening and broadening social networks, but have had an adverse affect because they reduce levels of face-to-face contact.
Evidence suggests that the biological effects of minimal face-to-face social interaction could alter the way genes work, upset immune response, hormone levels, the function of arteries, and influence mental performance, reported the BBC News.
Dr. Sigman warns that this could increase the risk of serious health problems: cancer, strokes, heart disease, and dementia.
Comment: An
opposing viewpoint points out that correlation does not imply causation, and that the increased use of social networks may actually be a positive trend that helps people counteract the effects of their disconnected and busy lifestyles.
Would you like a stroke with your burger? People who live in neighbourhoods with numerous fast food outlets are more likely to suffer a stroke than those in neighbourhoods with fewer such outlets, according to a new study of one Texas city.
This doesn't necessarily mean that their burgers, French fries and fried chicken cause stroke, says Lewis Morgenstern, an epidemiologist at the University of Michigan in Ann Arbor who presented the study at the International Stroke Conference in San Diego, California. Rather, fast food could be an indicator for other factors that lead to poor health, such as lack of exercise or poor air quality.
Morgenstern's team recorded all 1,247 strokes that occurred in Nueces County, Texas between 2000 and mid-2003. The region is home to Corpus Christi, a city home to 280,000 people and 264 fast food restaurants. His team split the city into 64 neighbourhoods with roughly the same population, based on census data.
Comment: An opposing viewpoint points out that correlation does not imply causation, and that the increased use of social networks may actually be a positive trend that helps people counteract the effects of their disconnected and busy lifestyles.