Caltech biologists locate brain’s processing point for acoustic signals essential to human communication Continue reading
If the brain goes hungry, Twinkies look a lot better, a study led by researchers at Yale University and the University of Southern California has found.
Brain imaging scans show that when glucose levels drop, an area of the brain known to regulate emotions and impulses loses the ability to dampen desire for high-calorie food, according to the study published online September 19 in The Journal of Clinical Investigation.
“Our prefrontal cortex is a sucker for glucose,” said Rajita Sinha, the Foundations Fund Professor of Psychiatry, and professor in the Department of Neurobiology and the Yale Child Study Center, one of the senior authors of the research.
The Yale team manipulated glucose levels intravenously and monitored changes in blood sugar levels while subjects were shown pictures of high-calorie food, low-calorie food and non-food as they underwent fMRI scans.
When glucose levels drop, an area of the brain called the hypothalamus senses the change. Other regions Continue reading
TEL-AVIV – A study conducted by Israeli researchers suggests that exposure to light, and possibly photosynthesis, may help disease-causing bacteria to invade fresh produce, making them impervious to washing.
According to background information in a report published in journal Applied and Environmental Microbiology, past studies have already shown that salmonella enterica attaches to the surface of fresh produce, and finds its way below the surface of the skin through pores called stomata, where it can hide from and resist washing and food sanitizers.
In the new study, researchers from the Agricultural Research Organization at the Volcani Center in Israel and Tel-Aviv University examined the role that light and photosynthesis might play on the ability of salmonella bacteria to infiltrate lettuce leaves via stomata.
They exposed sterile iceberg lettuce leaves to bacteria either in the light, in the dark, or in the dark after 30 minutes of exposure to light.
Incubation in the light or pre-exposure to light resulted in aggregation of bacteria around open stomata and invasion into the inner leaf tissue.
Incubation in the dark, on the other hand, resulted in a scattered attachment pattern and very little internalization.
According to the researchers, the increased propensity for internalization in the light may be due to several factors.
First, they say, in the absence of light plants enter a period of dormancy, where stomata are closed and no photosynthesis takes place. In the light, the stomata are open.
Additional findings also suggest that the bacteria are attracted to the open stomata by the nutrients produced during photosynthesis, which are not present in the dark.
“The elucidation of the mechanism by which Salmonella invades intact leaves has important implications for both pre- and postharvest handling of lettuce and probably other leafy vegetables. The capacity to inhibit internalization should limit bacterial colonization to the phylloplane and consequently might enhance the effectiveness of surface sanitizers,” say the researchers.
LONDON – Some social networking sites, like Facebook, could help improve a person’s working memory, according to an expert.
Dr. Tracy Alloway, a psychologist at Stirling University, says that working memory – the ability to recall things over a short period of time – could be the key to success.
She believes that it may be possible to train the brain’s working memory just like an athlete trains muscles, reports the Independent.
Alloway said that some technological inventions, such as Facebook, might actually improve working memory because they require people to hold a lot of information in their heads.
However, other such websites, like spell-checks and Twitter, which requires only small bite-sized phrases, may work against improving working memory.
Instead, these websites could be contributing to some people’s lack of success, she suggested.
Alloway said that she had devised an on-line game that can improve working memory, which may help the young develop working memory skills as well helping to combat memory loss in the elderly.
According to a report by ABC News, the study suggests the brain operates like a dual processor in a computer, with each of the brain’s two sides kicking into action depending on the content or context of the information.
Dr Culum Brown of the Department of Biological Sciences at Macquarie University in Sydney, and colleague Maria Magat, focused their research on several different types of Australian birds, such as gang-gangs, sulfur-crested cockatoos and Australian king parrots.
All of the birds participated in two tests designed to test their cerebral lateralisation, meaning how strongly each bird preferentially processes information using either hemisphere of the brain.
The first task was a simple pebble-seed discrimination test, where the birds had to pick seeds out of a background of similar sized pebbles.
The second task was more demanding.
The researchers attached food to the end of a suspended string that the birds had to manipulate with their beaks and feet in order to get the tasty reward.
Birds with a preference for using either of their eyes or either of their legs did better than birds that used both eyes and both legs equally.
This means that the most successful birds have a very strong cerebral lateralisation, which “is influenced by both genes and experience,” according to Brown.
He and Magat found that the pattern of lateralisation, left or right bias, did not predict success as much as the strength of the particular bias did.
Carrying the findings over to humans, this suggests, in part, that a right-handed person isn’t more successful than a left-handed one, and vice-versa.
But people who always favour a certain hand, foot or eye for certain tasks will likely perform better than those who don’t exhibit obvious preferences.
“Firstly, it means that a given hemisphere can become increasingly specialized at processing certain types of information,” he said.
According to Brown, assigning particular tasks to each side of the brain avoids conflict between the two hemispheres, and allows “multiple sources of information to be processed simultaneously, that is to say, animals can multitask like a dual processor in a computer.”
NEW YORK – New evidence suggests that daily nasal irrigation may increase the risk of sinus infections.
Nasal irrigation with warm saline has been promoted as way to cleanse the sinuses and help prevent infections. However, using this therapy too often may not be beneficial.
The latest study, presented at the American College of Allergy, Asthma, & Immunology (ACAAI) annual meeting, included 68 adults who used nasal irrigation frequently for one year and then stopped therapy for one year. The patients were compared to 24 control patients who did not discontinue nasal irrigation.
The researchers found that number of sinus infections decreased by 62.5 percent after the participants stopped using nasal irrigation. Additionally, after stopping nasal irrigation, they were 50 percent less likely to develop sinus infections than those who continued with daily therapy.
Mucus in the nose contains important immune system molecules that help the body fight against infections. Because nasal irrigation eliminates this mucus, the authors suspect that it may lead to an increased risk of infection.
CAIRO – Rich Egyptians living 3,500 years ago may have been walking around with the same clogged arteries that modern Americans now battle, according to a presentation Monday at the American Heart Association’s annual meeting.
A group of scientists said that, on a whim, they performed a computerized tomography (CT) scan on a collection of 22 mummies housed at the Egyptian National Museum of Antiquities in Cairo to see if they too suffered from the plaque build-up in arteries that lead to coronary artery disease.
“We didn’t believe it was going to be so intense,” said
The plaque was, of course, long gone. The mummies lived between 1981 B.C. and 364 A.D., and only 16 of the mummies had heart tissue left. However, doctors could see evidence of advanced atherosclerosis (plaque build-up that causes hardening of the arteries) by looking for calcium deposits in a CT scan used to diagnose people today.
Using gene therapy, the boffins successfully treated a pair of squirrel monkeys that could not differentiate between red and green.
The development could bring new treatments for a variety of different diseases that are triggered by faulty cone cells at the back of the eye. The problem can lead to diseases such as macular degeneration, which often causes complete blindness.
The research, which was led by
“Beyond that, we hope this technology will be useful in correcting lots of different vision disorders.”
NEW YORK – A new study hints that good oral care – regular brushing and flossing and trips to the dentist — may help aging adults keep their thinking skills intact.
In a study, researchers found that adults aged 60 and older with the highest versus the lowest levels of the gum disease-causing pathogen Porphyromonas gingivalis were three times more likely to have trouble recalling a three-word sequence after a period of time.
The findings, reported in the Journal of Neurology, Neurosurgery, and Psychiatry this month, are based on more than 2300 men and women who were tested for periodontitis and completed numerous thinking skills tests as part of the National Health and Nutrition Examination Survey III conducted between 1991 and 1994.
Overall 5.7 percent of the adults had trouble completing certain memory tasks and 6.5 percent failed reverse subtraction tests. Participants with the highest (greater than 119 units) versus the lowest (57 units or lower) pathogen levels were most likely to do poorly in these tests.
Research has already established a strong association between poor oral health and heart disease, stroke and diabetes, as well as Alzheimer’s disease. Gum disease could influence brain function through several mechanisms, the researchers note; for example, gum disease can cause inflammation throughout the body, a risk factor for loss of mental function.
In a related commentary,
SOURCE: Journal of Neurology, Neurosurgery, and Psychiatry, November 2009
LONDON – Scientists in the University of Leicester’s Department of Genetics have for the first time revealed that the male and female do truly communicate -at least at the fundamental genetic level.
The research counters scientific theory that the X and Y chromosomes – that define the sexes – do not communicate at all.
In the study,
“Recently it was shown that the Y chromosome can talk to itself – swapping bits of DNA from one region to another, and potentially giving it a way to fix mutations that might affect male fertility. In this new research we’ve now shown that it actually maintains a genetic conversation with the X chromosome, potentially giving it a way to fix other kinds of mutations, too. So, maybe it’s not quite the dysfunctional loner we have always imagined it to be,” said
It is the Y chromosome in men that determines maleness by triggering development of testes rather than ovaries in the early embryo.
“These days the X and Y are a very odd couple, but long ago, before mammals evolved, they were an ordinary pair of identical chromosomes, exchanging DNA in a companionable way through the process of genetic recombination. However, once the Y chromosome took on the job of determining maleness, they stopped talking to each other. The X remained much the same, but the Y set out on a path of degeneration that saw it lose many of its genes and shrink to about one third the size of the X. Some scientists have predicted that it will eventually vanish altogether,” said Jobling.
“These new findings from the Department of Genetics of the University of Leicester now challenge this interpretation of the Y chromosome’s fate,” he added.
The researchers discovered that the conversation between the X and Y chromosome goes both ways, and it is also clear that mutations arising on a decaying Y chromosome can perhaps be passed to the X – the Y chromosome’s revenge.
In future, the researchers will assess how widespread X-Y exchanges have been during evolution, and what the likely functional effects might be.
The study has been published in the American Journal of Human Genetics.
EXETER, UK – Encouraging elderly to talk about old times can actually improve their memory and limit effects of dementia, finds a new study.
The research team led by
During the study, the researchers recruited 73 people – aged between 70 and 90 and some with dementia – and split them into three groups.
The first group was made to sit around once a week in sets of five and reminisce about the old days such as childhood, weddings and family holidays, as well objects that could spark memories such as old-fashioned ink pots and hats.
After six weeks, the standard cognitive tests showed that the memory had improved by 12 per cent. Those suffering dementia saw an improvement of about eight per cent.
In contrast, the two other groups – one that was encouraged to play skittles – and another that was encouraged to have one on one chats showed very little improvement in their brain power.
“The people we were talking to were more than happy to bring up the war. It emerged as a very important part of their lives. As well as it improving their memory some people found it incredibly enjoyable,” the Telegraph quoted
“It doesn’t actually reverse dementia but it seems to make the most of their residual abilities,” she added.
“If you had a drug that could do that you would that you would make a lot of money. The drug in this case is the social group,” he said.
DENVER – Scientists from University of Colorado have revealed that inhaling measles vaccine can be more effective in combating the disease that causes 197,000 deaths each year globally.
While a liquid vaccine using a hypodermic needle is presently the only way to prevent the disease, they are often difficult to store, costly to transport and may be prone to contamination when shipped to developing countries.
The study led by
In order to produce the inhalant, the weakened measles virus must be mixed with high-pressure carbon dioxide to produce microscopic bubbles and droplets, which are then gently dried to produce an inhalable powder.
The powder is then puffed into a small inhaler-like device and administered.
The aerosol vaccine was shown effective in test animals, and human trials are expected to begin next year in India, where more than half of the world’s measles cases occur.
Aridis Pharmaceuticals have been working to develop a room temperature stable measles formulation that can be easily inhaled using cost-effective dry-powder inhalers in collaboration with the non-profit foundation PATH.
“There is a need for technologies that could stabilize the measles vaccine, as this would facilitate mass vaccination in developing world countries where transport, storage, administration costs and other complexities have limited vaccine coverage by 70 percent,” said Dr Satoshi Ohtake, from Aridis and the study’s principal investigator.
Ohtake’s study used a combination of mild spray drying process conditions and unique stabilizers to produce stable dry powders with excellent preservation of vaccine activity.
The potency of the dried vaccine was then tested while being stored at different Temperatures over several week-long periods.
The results found that the dry-powdered aerosol was stable for at least eight weeks at 37 degrees Celsius.
“This new method could potentially offer safer, more affordable and effective treatments to patients that need them the most,” Ohtake added.
ISTANBUL – The Turkish man crowned as the world’s tallest man suffers from a pituitary tumor which has resulted in his gigantic height.
Sultan Kosen stands eight-foot-one-inch tall and was unveiled as the tallest man in the world by the Guinness World Records. Kosen’s height is a result of a tumor in his pituitary gland, which has led to an over production of growth hormones, reports the National Geographic News.
The condition called pituitary gigantism has also led his feet to grow to almost 15 inches, while his hands are larger than 10 inches. It was only after the tumor was removed last year, that Kosen stopped growing.
The 27-year old is forced to use crutches as his height has weakened his knee joints.
The now-famous Kosen wants to travel around the world and meet a woman who would like to marry him.
LONDON – Scientists at the University College London have found that the hippocampus in the brain is responsible for our ability to organise the world into separate concepts.
Forming a concept involves selecting the important characteristics of our experiences and categorising them.
The degree to do this effectively is a defining characteristic of human intelligence.
However, not much is known about how conceptual knowledge is created and used in the brain.
Thus, to identify the brain regions responsible,
Conceptual rules based on the positions and combinations of the patterns governed whether the resulting outcome would be rain or sun, but the volunteers were not told this.
Instead, they rewarded correct predictions with cash prizes, encouraging the volunteers to deduce these conceptual rules.
In an initial learning phase, the different possible combinations were repeatedly shown to the participants, so that they could make their predictions by simply memorising previous outcomes and could also begin to realise that rules based on the positions and combinations of the patterns governed whether the result would be rain or sun.
In a second phase, the volunteers were provided with less information to encourage them to apply the rules they had identified, which made the researchers to separate those volunteers who had formed the concept in the learning phase from those who hadn’t.
During both experiments fMRI scanning was used to identify areas of brain activity.
It was found that in the first phase, they could tell if a volunteer would go on to apply concepts in the second phase by the degree of activity in their hippocampus, which is known to be responsible for learning and memory.
In the second phase, activity centred on the ventromedial prefrontal cortex (vMPFC), important in decision-making, was active.
The team concluded that the hippocampus creates and stores concepts, and passes this information onto the vMPFC where it is put to use during the making of decisions.
People with amnesia are also known to have problems forming concepts, so Kumaran is expecting his findings to lead to the development of improved teaching methods and other tools for the treatment of amnesiacs.
The study has been published in the journal Neuron.