Cell phones emit microwave radio-frequency radiation. Fact. Continue reading
Cell phones emit microwave radio-frequency radiation. Fact. Continue reading
A Canadian man who was believed to have been in a vegetative state for more than a decade, has been able to tell scientists that he is not in any pain.
It’s the first time an uncommunicative, severely brain-injured patient has been able to Continue reading
American doctors believe that it is possible to pinpoint the area of the brain that is activated when a person suffers from tinnitus, a chronic ringing of the head or ears that can be as quiet as a whisper or as loud as a jackhammer.
The team at Henry Ford Hospital in Detroit used a special scanner to map the locations in the brain. They hope it will allow more targeted therapies to be developed.
“Until now, we had no way of pinpointing the specific location of tinnitus in the brain,” says study co-author Michael D. Seidman, M.D., F.A.C.S., director of the Division of Otologic/Neurotolgic Surgery in the Department of Otolaryngology-Head and Neck Surgery at Henry Ford Hospital.
This imaging technique, magnetoencephalography (MEG), can determine the site of perception of tinnitus in the brain, which could in turn allow physicians to target the area with electrical or chemical therapies to lessen symptoms.
The findings have been presented Saturday, Oct. 3 at the American Academy of Otolaryngology-Head and Neck Surgery Foundation Annual Meeting and OTO EXPO.
“Since MEG can detect brain activity occurring at each instant in time, we are able to detect brain activity involved in the network or flow of information across the brain over a 10-minute time interval,” explains co-author Susan M. Bowyer, Ph.D. bioscientific senior researcher, Department of Neurology at Henry Ford Hospital.
“Using MEG, we can actually see the areas in the brain that are generating the patient’s tinnitus, which allows us to target it and treat it,” the expert added.
Imaging techniques currently used to study tinnitus in the brain – PET and fMRI – provide a general location but are not successful at determining the specific site in the brain that is generating tinnitus symptoms.
MEG, by comparison, measures the very small magnetic fields generated by intracellular electrical currents in the neurons of the brain. Only 20 sites in the U.S., including Henry Ford, are equipped with a MEG scanner. MEG is presently used at these sites for pre-surgical brain mapping for patients undergoing surgery for brain tumor removal or Epilepsy treatment.
“With PET and fMRI, most of the auditory cortex of the brain lights up with activity during imaging. MEG, however, is a much more sophisticated machine and it can identify a specific tone or topic point, so only a small area in the brain lights up. It’s like having the lights on in only the city of Detroit, compared to having the lights on in the entire state of Michigan,” explains Dr. Seidman, director of the Otolaryngology Research Laboratory and co-director of the Tinnitus Center at Henry Ford.
For the study, Dr. Seidman and his colleagues collected MEG results from 17 patients with tinnitus and 10 patients without tinnitus. MEG data were collected for 10 minutes, and then digitally filtered. Study participants wore ear plugs to eliminate outside sounds, and kept their eyes open and fixated on one point on the ceiling in the room during testing.
With tinnitus patients who have ringing in one ear (unilateral tinnitus), MEG imaging detected the greatest amount of activity in the auditory cortex on the opposite site of the brain from their perceived tinnitus. For patients with ringing in the head or both ears (bilateral tinnitus), MEG imaging revealed activity in both hemispheres of the brain, with greater activity appearing in the opposite side of the brain of the strongest perception of tinnitus.
Patients without tinnitus had multiple small active areas in the brain, but no particular areas were found to be highly coherent during the 10-minute MEG scan.
Ultimately, Dr. Seidman says the study establishes MEG as an effective clinical tool for localizing the probably source of tinnitus in patients’ brains. It also has the potential to assist with the development of future interventional strategies to alleviate tinnitus.
Researchers from the US and Canada have for the first time found evidence that a few glasses of blueberry juice a day improved memory in older adults; the findings come from a small study of 70-year olds showing early signs of memory loss, and the researchers suggest the findings establish a basis for comprehensive human clinical trials to test whether blueberries really deserve their growing reputation as a memory enhancer.
The study was the work of Dr Robert Krikorian, Associate Professor of Clinical Psychiatry at the University of Cincinnati Academic Health Center in Cincinnati, Ohio and colleagues, and a report about it appears in the 4 January ASAP issue of the American Chemical Society’s bi-weekly Journal of Agricultural and Food Chemistry.
The authors wrote there is an urgent need to develop preventive approaches to dementia which is on the rise as our population ages and there is no effective therapy for it.
Blueberries contain polyphenols, comprising mostly anthocyanins, which are known to have antioxidant and anti-inflammatory effects, combating oxidative stress, which contributes to some neurodegenerative and cardiovascular diseases.
A paper in a February 2008 issue of the Journal of Agricultural and Food Chemistry, that presented the findings of the 2007 International Berry Health Benefits Symposium, suggested that these compounds have beneficial effects on cancer, aging, neurological diseases, inflammation, diabetes and bacterial infections.
The authors also wrote that animal studies have found they contribute to increased neuron-to-neuron communication, improved use of glucose in the brain, and are involved in memory function.
It would be reasonable to expect, therefore, that such compounds might delay neurodegeneration in humans, hence the motive for this work.
For the study, Krikorian and colleagues recruited 9 people in their 70s showing early signs of memory changes, got them to complete memory and cognition tests, then asked them them to drink two to two and a half cups of commercially available blueberry juice a day.
12 weeks later, the volunteers underwent the same memory and cognition tests. When they compared the before and after results, the researchers found the volunteers who had drunk blueberry juice had improved paired associate learning (p = 0.009) and word list (p = 0.04) recall. The results also showed a trend toward reduced depressive symptoms (p = 0.08) and lower glucose levels (p = 0.10), said the researchers.
These results were then compared with the results of another trial of the same design involving a demographically matched group of people in their 70s who also had early signs of memory changes, but this time they were given a placebo that they thought was blueberry juice.
The researchers said that the improved performance of the blueberry group over the placebo group on the paired associated memory test was similar to the difference in the before and after results observed in the blueberry group in the earlier trial.
They concluded that:
“The findings of this preliminary study suggest that moderate-term blueberry supplementation can confer neurocognitive benefit and establish a basis for more comprehensive human trials to study preventive potential and neuronal mechanisms.”
“These preliminary memory findings are encouraging and suggest that consistent supplementation with blueberries may offer an approach to forestall or mitigate neurodegeneration,” they wrote.
Source: American Chemical Society.
Training and experience can affect how a person’s brain is organized, says a US study that compared 20 music conductors and 20 people with no music training.
All the participants were between the ages of 28 and 40. The conductors had an average of more than 10 years experience as a band or orchestra director in middle or high school.
The researchers used functional magnetic resonance imaging (fMRI) to monitor the participants’ brain activity while they performed a difficult hearing task that involved listening for two tones. They had to keep their eyes opened while doing the task.
Experience and brain functioning
Initially, both the conductors and non-musicians showed reduced activity in the brain’s visual processing area and increased activity in the auditory part of the brain. But as the task became harder, only the non-musicians tuned out more of their visual sense. This suggests that the conductors’ music training and experience altered the way their brains work, the researchers said.
“Because the task was equally difficult for everybody, the difference observed between conductors and non-musicians must be related to a change in how they deal with irrelevant sensory information and not just their ability to do the task,” lead author W. David Hairston, a postdoctoral fellow in radiology at the Advanced Neuroscience Imaging Research Laboratory at Wake Forest University Baptist Medical Centre in Winston-Salem, N.C., said in a prepared statement.
“In general, based on the non-musicians, we suggest that the brain actively increases how much information from other senses gets filtered out or ignored when you have to concentrate really hard on one sense,” Hairston said.
He noted that conductors routinely must differentiate between subtle differences in sounds and often have to do this while reading scores and watching/communicating with their musicians. This leads to an ability to focus on a difficult auditory task without having to increase suppression of visual information.
The study results “show how the brain filters information from different senses is very flexible and adaptive and changes with the demands of the task at hand. Additionally, how this operates can change with highly specialized training and experience,” Hairston said.
Even though the study participants ate whatever they wanted on their non-fasting days, they lost an average of 5.6 kilograms (about 12 pounds) after eight weeks,
What’s more, their total and “bad” LDL cholesterol levels dropped, and their blood pressure fell.
“People lost anywhere from about 7 pounds to about 30 pounds and that was in a very short amount of time,” Varady said. And, she added, the program was pretty easy for the study participants to follow.
People typically try to lose weight by cutting their calorie intake every day, Varady and her team note in the American Journal of Clinical Nutrition. A much rarer approach, they add, is to have people alternate “feed days” with “fast days.” Studies in normal and overweight people have shown that this strategy can indeed help people lose weight and improve their cholesterol levels.
To test alternate-day fasting in obese adults, Varady and her colleagues had 12 obese women and 4 obese men begin by eating normally for a two-week control period. Then, for eight weeks, they ate just 25 percent of the calories they needed to maintain their weight, between noon and 2 p.m., every other day.
For the first four weeks, the researchers provided study participants with their fasting day meal, while for the next four, study participants met with a dietitian every week and prepared the meal themselves.
Study participants lost about 0.7 kilograms (1.5 pounds) every week. At the end of the eight-week diet, their total cholesterol had dropped by 21 percent, on average, while their LDL cholesterol had dropped 25 percent. Moreover, their systolic blood pressure (the upper number in a blood pressure reading) had fallen by an average of five points.
While Varady and her team had thought people might overeat on their non-fasting day in order to compensate, this turned out not to be true; people typically ate between 100 percent or 125 percent of their calorie needs on their all-you-can eat days.
“I think it’s probably because their stomachs kind of shrunk,” she said.
The next step, the researcher said, will be to figure out if people can maintain the on-off approach for a longer period of time, to continue to lose weight or to maintain a healthy weight.
Anyone who wants to give the diet a try, she added, should meet with their doctor or a dietitian first.
SOURCE: American Journal of Clinical Nutrition, November 2009.
How Some People Maintain Weight Loss, Others Don’t
The researchers showed that when individuals who had kept the weight off for several years were shown pictures of food, they were more likely to engage the areas of the brain associated with behavioral control and visual attention, as compared to obese and normal weight participants.
The findings of the study suggest that successful weight loss maintainers may learn to respond differently to food cues.
“Our findings shed some light on the biological factors that may contribute to weight loss maintenance. They also provide an intriguing complement to previous behavioral studies that suggest people who have maintained a long-term weight loss monitor their food intake closely and exhibit restraint in their food choices,” said lead author
Long-term weight loss maintenance continues to be a major problem in obesity treatment.
Participants in behavioral weight loss programs lose an average of 8 to 10 percent of their weight during the first six months of treatment, and will maintain approximately two-thirds of their weight loss after one year.
However, despite intensive efforts, weight regain appears to continue for the next several years, with most patients returning to their baseline weight after five years.
The researchers used functional magnetic resource imaging (fMRI) to study the brain activity of three groups- 18 individuals of normal weight, 16 obese individuals (defined as a body mass index of at least 30), and 17 participants who have lost at least 30 lbs and have successfully maintained that weight loss for a minimum of three years.
When the participants were shown pictures of food items after a four-hour fast, it was found that those in the successful weight loss maintenance group responded differently to these pictures compared to the other groups.
Specifically, researchers observed strong signals in the left superior frontal region and right middle temporal region of the brain – a pattern consistent with greater inhibitory control in response to food images and greater visual attention to food cues.
“It is possible that these brain responses may lead to preventive or corrective behaviors – particularly greater regulation of eating – that promote long-term weight control. However, future research is needed to determine whether these responses are inherent within an individual or if they can be changed,” said McCaffery.
The study has been published in the American Journal of Clinical Nutrition.