People voluntarily pick what information they store in short-term memory. Now, using functional magnetic resonance imaging (fMRI), researchers can see just what information people are holding in memory based only on patterns of activity in the brain.

Psychologists from the University of Oregon and the University of California, San Diego, reported their findings in the February issue of Psychological Science. By analyzing blood-flow activity, they were able to identify the specific color or orientation of an object that was intentionally stored by the observer.

The experiments, in which subjects viewed a stimulus for one second and held a specific aspect of the object in mind after the stimulus disappeared, were conducted in the UO's Robert and Beverly Lewis Center for Neuroimaging. In 10-second delays after each exposure, researchers recorded brain activity during memory selection and storage processing in the visual cortex, a brain region that they hypothesized would support the maintenance of visual details in short-term memory.

"Another interesting thing was that if subjects were remembering orientation, then that pattern of activity during the delay period had no information about color, even though they were staring at a colored-oriented stimulus," said Edward Awh, a UO professor of psychology. "Likewise, if they chose to remember color we were able to decode which color they remembered, but orientation information was completely missing."

Researchers used machine-learning algorithms to examine spatial patterns of activation in the early visual cortex that are associated with remembering different stimuli, said John T. Serences, professor of psychology at UC-San Diego. "This algorithm," he said, "can then be used to predict exactly what someone is remembering based on these activation patterns."

Increases in blood flow, as seen with fMRI, are measured in voxels -- small units displayed in a 3-D grid. Different vectors of the grid, corresponding to neurons, respond as subjects view and store their chosen memories. Based on patterns of activity in an individual's visual cortex, located at the rear of the brain, researchers can pinpoint what is being stored and where, Awh said.

The study is similar to one published this month in Nature and led by Vanderbilt University neuroscientist Frank Tong and colleagues, who were able to predict with 80-percent-plus accuracy which patterns individuals held in memory 11 seconds after seeing a stimulus.

"Their paper makes a very similar point to ours," Awh said, "though they did not vary which 'dimension' of the stimulus people chose to remember, and they did not compare the pattern of activity during sensory processing and during memory. They showed that they could look at brain activity to classify which orientation was being stored in memory."

What Awh and colleagues found was that the sensory area of the brain had a pattern of activity that represented only an individual's intentionally stored aspect of the stimulus. This voluntary control in memory selection, Awh said, falls in line with previous research, including that done by Awh and co-author Edward K. Vogel, also of the UO, that there is limited capacity for what can be stored at one time. People choose what is important and relevant to them, Awh said.

"Basically, our study shows that information about the precise feature a person is remembering is represented in the visual cortex," Serences said, "This is important because it demonstrates that people recruit the same neural machinery during memory as they do when they see a stimulus."

Women with higher intake of calcium appear to have a lower risk of cancer overall, and both men and women with high calcium intakes have lower risks of colorectal cancer and other cancers of the digestive system.

Calcium is known to benefit bone health, according to background information in the article. Because of this, the Institute of Medicine recommends 1,200 milligrams of calcium for adults age 50 and older, and the 2005 dietary guidelines for Americans recommend 3 cups per day of low-fat or fat-free dairy products. Studies of dairy products, calcium intake and cancer have revealed different results for different cancer sites.

Yikyung Park, Sc.D., of the National Cancer Institute, Bethesda, Md., and colleagues analyzed data from 293,907 men and 198,903 women who participated in the National Institutes of Health-AARP Diet and Health Study. Participants took a food frequency questionnaire when they enrolled in the study between 1995 and 1996, reporting how much and how often they consumed dairy and a wide variety of other foods and whether they took supplements. Their records were then linked with state cancer registries to identify new cases of cancer through 2003.

Over an average of 7 years of follow-up, 36,965 cancer cases were identified in men and 16,605 in women. Calcium intake was not associated with total cancer in men but was in women-the risk decreased in women with intake of up to 1,300 milligrams per day, after which no further risk reduction was observed.

"In both men and women, dairy food and calcium intakes were inversely associated with cancers of the digestive system," the authors write. The one-fifth of men who consumed the most calcium through food and supplements (about 1,530 milligrams per day) had a 16 percent lower risk of these types of cancer than the one-fifth who consumed the least (526 milligrams per day). For women, those in the top one-fifth of calcium consumption (1,881 milligrams per day) had a 23 percent lower risk than those in the bottom one-fifth (494 milligrams per day). The decreased risk was particularly pronounced for colorectal cancer. Calcium and dairy food intake was not associated with prostate cancer, breast cancer or cancer in any other anatomical system besides the digestive system.

"Dairy food, which is relatively high in potentially anticarcinogenic nutrients such as calcium, vitamin D and conjugated linoleic acid, has been postulated to protect against the development of colorectal and breast cancer," the authors write. Calcium has been shown to reduce abnormal growth and induce normal turnover among cells in the gastrointestinal tract and breast. In addition, it binds to bile and fatty acids, potentially reducing damage to the mucous membrane in the large intestine.

A new study involving iPods and teenagers by the University of Colorado at Boulder and Children's Hospital Boston indicates teenagers who receive pressure from their peers or others to turn down the volume of their iPods instead turn them up higher.

The study also showed that teen boys listen louder than teen girls, and teens who express the most concern about the risk for and severity of hearing loss from iPods actually play their music at higher levels than their peers, said CU-Boulder audiologist and doctoral candidate Cory Portnuff, who headed up the study. Such behaviors put teens at an increased risk of music-induced hearing loss, he said.

The results of the study, conducted by Portnuff and Associate Professor Kathryn Arehart of CU-Boulder's speech, language and hearing sciences department and Brian Fligor, director of diagnostic audiology at Children's Hospital Boston, were presented at the annual Hearing Conservation Conference held in Atlanta last week. Children's Hospital Boston is the teaching hospital of Harvard Medical School.

Other findings from the study indicated teens play their music louder than young adults, and teens may inaccurately perceive how loud they are playing their music. The good news, said Portnuff, is that teens in the study who understand the benefits of listening at a lower volume have less of a risk for hearing loss.

"We really don't a have good explanation for why teens concerned about the hearing loss risk actually play their music louder than others," he said. "But we do know that teens who knew what the benefits were of listening at lower levels had less hearing loss risk, which is why we believe targeted education is the key."

Portnuff said the new study indicated a relatively small percentage of teens -- somewhere between 7 and 24 percent -- listen to their iPods and MP3 players at risky levels. "We don't seem to be at an epidemic level for hearing loss from music players," Portnuff said.

The new findings regarding the sound volumes selected by music-playing teens today are similar to findings 20 years ago when Walkman audio cassette players first came onto the market, Portnuff said. "One of the concerns we have today is that while Walkmans back then operated on AA batteries that usually began to run down after several hours, teenagers today can listen to their iPods for up to 20 hours without recharging them."

A 2006 study by Portnuff and Fligor indicated a typical person can safely listen to an iPod for 4.6 hours per day at 70 percent volume using stock earphones. But listening to music at full volume for more than five minutes a day using stock earphones increased the risk of hearing loss in a typical person, according to the study.

The 2006 study also concluded that individuals can safely listen to iPods for 90 minutes a day with stock earphones if the volume is at 80 percent of maximum levels without greatly increasing the risk of hearing loss, he said.

Loud music can potentially damage delicate hair cells in the inner ear that convert mechanical vibrations, or sound, to electrical signals that the brain interprets as sound, said Portnuff. "Over time, the hair cells can become permanently damaged and no longer work, producing hearing loss."

Dr. Gino Fallone and his team of medical physicists at the Cross Cancer Institute in Edmonton are the first in the world to successfully take a magnetic resonance (MR) image at the same time radiation therapy is being delivered.

This discovery has the potential to increase the likelihood of tumour control by an estimated 20 to 40 per cent. The discovery also makes radiation therapy more accessible for cancers difficult to treat with radiation because of organ movement, such as liver, stomach and pancreatic cancers.

Fallone, the director of medical physics at the Cross Cancer Institute and professor of oncology at the University of Alberta says: "We were told by some that it couldn't be done." Mutual interferences (magnetic and radio frequency fields) make the linear accelerator (linac) and the MR systems "allergic" to each other, an obstacle previously thought to be insurmountable.

"However, we've now proved our design principle and can proceed to developing a larger (whole body system) prototype and eventually to clinical trials," says Fallone.

Dr. Fallone and his team are the first to develop and build a prototype linac-MR hybrid (head system) that has successfully taken MR images of objects while linac radiation is being delivered. The prototype gives the ability to guide the curative radiation to the tumour at the same time the image is being taken.

Current state-of-the-art equipment allows for a CT snapshot moments before delivering the radiation. Fallone says it is like relying on blurry snapshot that does not capture soft tissue well. The linac-MR prototype provides clear video images, including soft tissue, and allows one to guide radiation in real time to the tumour.

The prototype will also minimize the need to radiate a margin of healthy tissue, currently required to ensure the entire tumour has been treated and will allow for a higher dose of radiation.

A vast study on over 20,000 people in China demonstrates the significant role of so-called indoor air pollution, particularly smoke from coal or wood fires in kitchens. Its results are published today in the online edition of the ERJ, the scientific publication of the European Respiratory Society (ERS).

COPD (Chronic Obstructive Pulmonary Disease), which includes chronic bronchitis and emphysema, represents a major global public health problem. While this severe respiratory condition is known to be caused mainly by smoking, which is very widespread in China, it is far from rare among non-smokers. Indeed, as shown by this study in the European Respiratory Journal (ERJ), over a third of Chinese COPD patients (38.6%) have never touched a cigarette!

The prevalence of COPD among non-smokers varies widely from one country to another: from only about 6% in Mexico City, it rises to 9% in the USA and nearly 16% in Santiago de Chile. This range points clearly to important differences in lifestyle, behaviour and exposure to various toxic substances.

It was precisely in order to identify COPD risk factors among non-smokers in China that Pixin Ran (University Hospital of Guangzhou, Guangdong, China) decided to undertake, with his team, a vast study on the basis of a known cohort of Chinese COPD sufferers. The cohort (known as CESCOPD), established between 2002 and 2004, was recruited in seven Chinese provinces with a total population of over 230 million people in rural and urban areas.

From 20,245 subjects aged over 40, interviewed and examined by spirometry, the team analysed the data of 12,471 non-smokers and 1,024 smokers with COPD. The selected volunteers completed a detailed questionnaire on their smoking habits, personal and familial antecedents of respiratory disease, and the presence of respiratory symptoms, especially chronic cough. They were also questioned about their lifestyle, especially exposure to smoke from solid fuels (mainly wood and coal, but also grass and dung) used for heating and cooking. The COPD diagnosis was duly established using spirometry with bronchodilation tests.

Kitchen smoke a major suspect

The groundbreaking results published in the ERJ will shed new light on the characteristics of COPD in China. Pixin Ran shows, firstly, that a third of COPD cases (38.6%) are unconnected with tobacco, and 5.2% of affected non-smokers have COPD. Importantly, though, the respiratory disease was found to have a very different profile among the non-smokers. By adjusting all of the variables, Pixin Ran and his team are able to conclude that exposure to various types of smoke in the home (coal, biomass etcŠ), is a leading cause of COPD in non-smokers. Passive smoking naturally plays a part, but on a comparable level to inadequate ventilation of the kitchen.

The Chinese study shows that almost half of the non-smokers (44.6%) had been exposed, for at least one year, to smoke from the burning of biomass for cooking, and 73.2% had been exposed to smoke from coal used for heating or cooking. Poor kitchen ventilation was an aggravating factor in four out of ten cases. This is a matter of no small importance: the researchers found that not only women are harmed by cooking smoke. Men, who had been exposed to it, also pay a heavy price. Furthermore, the authors of the ERJ article report that nearly four-fifths of the Chinese non-smokers (78.2%) had lived with tobacco fumes. While it is already common knowledge that children of smoking parents are more likely to suffer from respiratory disease when they reach adulthood, the problem seems particularly acute in China, where nearly 40% of adults smoke, a much higher proportion than in many European countries.

Prevention is possible

This original Chinese study also reveals other important factors. Pixin Ran and his colleagues emphasise, for example, that COPD is commoner among older men and those with lower educational attainment, or with family or personal antecedents of respiratory disease. A low body mass index (BMI) is also statistically associated with COPD. However, occupational exposure to fumes or dust was not identified as an independent risk factor among non-smokers. The relative significance of the different parameters also varied slightly according to the stage of development of the respiratory condition.