Posts tagged science

UCLA researchers now have the first evidence that bacteria ingested in food can affect brain function in humans. In an early proof-of-concept study of healthy women, they found that women who regularly consumed beneficial bacteria known as probiotics through yogurt showed altered brain function, both while in a resting state and in response to an emotion-recognition task.

The study, conducted by scientists with the Gail and Gerald Oppenheimer Family Center for Neurobiology of Stress, part of the UCLA Division of Digestive Diseases, and the Ahmanson–Lovelace Brain Mapping Center at UCLA, appears in the current online edition of the peer-reviewed journal Gastroenterology.

The discovery that changing the bacterial environment, or microbiota, in the gut can affect the brain carries significant implications for future research that could point the way toward dietary or drug interventions to improve brain function, the researchers said.

"Many of us have a container of yogurt in our refrigerator that we may eat for enjoyment, for calcium or because we think it might help our health in other ways," said Dr. Kirsten Tillisch, an associate professor of medicine in the digestive diseases division at UCLA’s David Geffen School of Medicine and lead author of the study. "Our findings indicate that some of the contents of yogurt may actually change the way our brain responds to the environment. When we consider the implications of this work, the old sayings ‘you are what you eat’ and ‘gut feelings’ take on new meaning."

Researchers have known that the brain sends signals to the gut, which is why stress and other emotions can contribute to gastrointestinal symptoms. This study shows what has been suspected but until now had been proved only in animal studies: that signals travel the opposite way as well.

"Time and time again, we hear from patients that they never felt depressed or anxious until they started experiencing problems with their gut," Tillisch said. "Our study shows that the gut–brain connection is a two-way street."

The small study involved 36 women between the ages of 18 and 55. Researchers divided the women into three groups: one group ate a specific yogurt containing a mix of several probiotics — bacteria thought to have a positive effect on the intestines — twice a day for four weeks; another group consumed a dairy product that looked and tasted like the yogurt but contained no probiotics; and a third group ate no product at all.

Functional magnetic resonance imaging (fMRI) scans conducted both before and after the four-week study period looked at the women’s brains in a state of rest and in response to an emotion-recognition task in which they viewed a series of pictures of people with angry or frightened faces and matched them to other faces showing the same emotions. This task, designed to measure the engagement of affective and cognitive brain regions in response to a visual stimulus, was chosen because previous research in animals had linked changes in gut flora to changes in affective behaviors.

The researchers found that, compared with the women who didn’t consume the probiotic yogurt, those who did showed a decrease in activity in both the insula — which processes and integrates internal body sensations, like those from the gut — and the somatosensory cortex during the emotional reactivity task.

Further, in response to the task, these women had a decrease in the engagement of a widespread network in the brain that includes emotion-, cognition- and sensory-related areas. The women in the other two groups showed a stable or increased activity in this network.

During the resting brain scan, the women consuming probiotics showed greater connectivity between a key brainstem region known as the periaqueductal grey and cognition-associated areas of the prefrontal cortex. The women who ate no product at all, on the other hand, showed greater connectivity of the periaqueductal grey to emotion- and sensation-related regions, while the group consuming the non-probiotic dairy product showed results in between.

The researchers were surprised to find that the brain effects could be seen in many areas, including those involved in sensory processing and not merely those associated with emotion, Tillisch said.

The knowledge that signals are sent from the intestine to the brain and that they can be modulated by a dietary change is likely to lead to an expansion of research aimed at finding new strategies to prevent or treat digestive, mental and neurological disorders, said Dr. Emeran Mayer, a professor of medicine (digestive diseases), physiology and psychiatry at the David Geffen School of Medicine at UCLA and the study’s senior author.

"There are studies showing that what we eat can alter the composition and products of the gut flora — in particular, that people with high-vegetable, fiber-based diets have a different composition of their microbiota, or gut environment, than people who eat the more typical Western diet that is high in fat and carbohydrates," Mayer said. "Now we know that this has an effect not only on the metabolism but also affects brain function."

The UCLA researchers are seeking to pinpoint particular chemicals produced by gut bacteria that may be triggering the signals to the brain. They also plan to study whether people with gastrointestinal symptoms such as bloating, abdominal pain and altered bowel movements have improvements in their digestive symptoms which correlate with changes in brain response.

Meanwhile, Mayer notes that other researchers are studying the potential benefits of certain probiotics in yogurts on mood symptoms such as anxiety. He said that other nutritional strategies may also be found to be beneficial.

By demonstrating the brain effects of probiotics, the study also raises the question of whether repeated courses of antibiotics can affect the brain, as some have speculated. Antibiotics are used extensively in neonatal intensive care units and in childhood respiratory tract infections, and such suppression of the normal microbiota may have long-term consequences on brain development.

Finally, as the complexity of the gut flora and its effect on the brain is better understood, researchers may find ways to manipulate the intestinal contents to treat chronic pain conditions or other brain related diseases, including, potentially, Parkinson’s disease, Alzheimer’s disease and autism.

Answers will be easier to come by in the near future as the declining cost of profiling a person’s microbiota renders such tests more routine, Mayer said.

(Source: newsroom.ucla.edu)

Support the BRAIN Initiative, but don’t overlook the neurogenomic diagnostics that are already driving breakthroughs in brain and rare neurological disorders.

On April 2^nd, 2013, President Obama proposed a forward-thinking, $100 million research program designed to unlock the mysteries of the human brain. The BRAIN (Brain Research through Advancing Innovative Neurotechnologies) Initiative seeks to identify how brain cells and neural circuits interact in order to inform the development of future treatments for brain disorders, including Alzheimer’s disease, epilepsy, and traumatic brain injury.

This Initiative could favorably contribute to medical practice years from now. It should not, however, overshadow the potential of neurogenomic advances to improve the diagnosis, treatment and management of neurological disorders right now.

Most of my career has focused on neurogenomics. During the Human Genome Project era, I managed a clinical neurogenomics program at the National Institutes of Health to further understanding the genetic underpinnings of neurological disorders to help diagnose, treat, cure, and even prevent disease. Today, I oversee the development of neurodiagnostics for the neurology business of Quest Diagnostics, with an emphasis on rare neurological disorders, autism, and dementias.

Over the years, I’ve come to identify certain obstacles that prevent the translation of neurogenomic science into effective clinical management. These obstacles are surmountable, but they require a fundamental shift in how care is delivered to patients with neurological disorders.

Our current healthcare system groups healthcare professionals into two categories: generalists, such as primary care physicians and internists, and specialists, including neurologists. We assume that the former have the knowledge to reliably refer patients, when appropriate, to the latter. This may have been a fair assumption in the past, but in the age of genomic medicine, is it still valid?

In the case of neurogenomic disorders, such as genetic forms of epilepsy, neuromuscular disorders, dementia, and developmental disabilities overlapping clinical signs and symptoms often present a diagnostic challenge for neurologists, and even more so for generalists. A dearth of clinical information available on rare disorders, and the infrequency with which primary care physicians come in contact with effected patients, makes diagnosis even more difficult.

Dravet syndrome, for example, is a rare and catastrophic form of infantile epilepsy that is associated with a high incidence of developmental delays and even SUDEP (sudden unexplained death in epilepsy). Dravet is caused by a genetic defect in the SCN1A gene-affecting sodium channel. While not curable, the condition can be managed if diagnosed—but only if treating physicians are aware of the disorder, treatment options, and the detrimental effects of certain anticonvulsants.

Through advances in laboratory diagnostics, physicians are increasingly equipped to pinpoint the molecular causes of these diseases—some of which are amenable to treatment. But too often, the only clinicians who know about the tests and treatment options are specialists.

We must work more closely with medical societies and advocacy groups to educate primary care professionals and even patients in the value of, and tools for, diagnosing and treating neurological disorders.

Neurogenomic research is revealing that some rare disorders share similar molecular markers and mechanisms. By categorizing these rare disorders into clinical areas, we potentially reduce an otherwise lengthy diagnostic process for the patient and advance the development of new treatment options. Greater investment in new diagnostics that pinpoint molecular markers for disease will help remove the mystery that clouds the diagnosis of many disorders.

Too few clinicians, including neurologists, can keep on top of the rapid evolution of genomic science and diagnostics. As a result, patients are often referred from physician to physician, and administered test after test, in a protracted process to diagnose and treat. This wastes healthcare dollars. More importantly, it creates terrible anxiety and frustration for patients.

To alleviate this problem, medical societies need to do more to cultivate sub-specialists in neurogenomics—clinicians who have deep specialized expertise in specific neurological diseases, particularly rare disorders. With such experience, these experts can more efficiently and reliably diagnose the patient’s disorder.

While the BRAIN Initiative may yield clinically valuable insights in the future, scientists and physicians can do a great deal now with current technologies to translate genomic knowledge into effective diagnosis, management and, in some cases, treatment. With greater genomics education and collaboration, we can help improve the quality of life for patients with neurological disorders—and that, ultimately, is the most meaningful measurement of success.

(Source: the-scientist.com)

New array measures vibrations across the skin, may help engineers design optimal, wearable tactile displays.

In the near future, a buzz in your belt or a pulse from your jacket may give you instructions on how to navigate your surroundings.

Think of it as tactile Morse code: vibrations from a wearable, GPS-linked device that tell you to turn right or left, or stop, depending on the pattern of pulses you feel. Such a device could free drivers from having to look at maps, and could also serve as a tactile guide for the visually and hearing impaired.

Lynette Jones, a senior research scientist in MIT’s Department of Mechanical Engineering, designs wearable tactile displays. Through her work, she’s observed that the skin is a sensitive — though largely untapped — medium for communication.

“If you compare the skin to the retina, you have about the same number of sensory receptors, you just have them over almost two square meters of space, unlike the eye where it’s all concentrated in an extremely small area,” Jones says. “The skin is generally as useful as a very acute area. It’s just that you need to disperse the information that you’re presenting.”

Knowing just how to disperse tactile information across the skin is tricky. For instance, people may be much more sensitive to stimuli on areas like the hand, as opposed to the forearm, and may respond best to certain patterns of vibrations. Such information on skin responsiveness could help designers determine the best configuration of motors in a display, given where on the skin a device would be worn.

Now Jones has built an array that precisely tracks a motor’s vibrations through skin in three dimensions. The array consists of eight miniature accelerometers and a single pancake motor — a type of vibrating motor used in cellphones. She used the array to measure motor vibrations in three locations: the palm of the hand, the forearm and the thigh. From her studies with eight healthy participants, Jones found that a motor’s mechanical vibrations through skin drop off quickly in all three locations, within 8 millimeters from where the vibrations originated.

Jones also gauged participants’ perception of vibrations, fitting them with a 3-by-3 array of pancake motors in these three locations on the body. While skin generally stopped vibrating 8 millimeters from the source, most people continued to perceive the vibrations as far away as 24 millimeters.

When participants were asked to identify specific locations of motors within the array, they were much more sensitive on the palm than on the forearm or thigh. But in all three locations, people were better at picking out vibrations in the four corners of the array, versus the inner motors, leading Jones to posit that perhaps people use the edges of their limbs to localize vibrations and other stimuli.

“For a lot of sensory modalities, you have to work out what it is people can process, as one of the dictates for how you design,” says Jones, whose results will appear in the journal IEEE Transactions on Haptics. “There’s no point in making things much more compact, which may be a desirable feature from an engineering point of view, but from a human-use point of view, doesn’t make a difference.”

Mapping good vibrations

In addition to measuring skin’s sensitivity to vibrations, Jones and co-author Katherine Sofia ’12 found that skin has a strong effect on motor vibrations. The researchers compared a pancake motor’s frequency of vibrations when mounted on a rigid structure or on more compliant skin. They found that in general, skin reduced a motor’s vibrations by 28 percent, with the forearm and thigh having a slightly stronger dampening effect than the palm of the hand.

The skin’s damping of motor vibrations is significant, Jones says, if engineers plan to build tactile displays that incorporate different frequencies of vibrations. For instance, the difference between two motors — one slightly faster than the other — may be indistinguishable in certain parts of the skin. Likewise, two motors spaced a certain distance apart may be differentiable in one area but not another.

“Should I have eight motors, or is four enough that 90 percent of the time, I’ll know that when this one’s on, it’s this one and not that one?” Jones says. “We’re answering those sorts of questions in the context of what information you want to present using a device.”

Roberta Klatzky, a professor of psychology at Carnegie Mellon University, says that measurements taken by Jones’ arrays can be used to set up displays in which the location of a stimulus — for example, a pattern to convey a letter — is important.

“A major challenge is to enable people to tell the difference between patterns applied to the skin as, for example, blind people do when reading Braille,” says Klatzky, who specializes in the study of spatial cognition. “Lynette’s work sets up a methodology and potential guidelines for effective pattern displays.”

Creating a buzz

Jones sees promising applications for wearable tactile displays. In addition to helping drivers navigate, she says tactile stimuli may direct firefighters through burning buildings, or emergency workers through disaster sites. In more mundane scenarios, she says tactile displays may help joggers traverse an unfamiliar city, taking directions from a buzzing wristband, instead of having to look at a smartphone. 

Using data from their mechanical and perceptual experiments, Jones’ group is designing arrays that can be worn across the back and around the wrist, and is investigating various ways to present vibrations. For example, a row of vibrations activated sequentially from left to right may tell a driver to turn right; a single motor that buzzes with increasing frequency may be a warning to slow down.

“There’s a lot of things you can do with these displays that are fairly intuitive in terms of how people respond,” Jones says, “which is important because no one’s going to spend hours and hours in any application, learning what a signal means.”

(Source: web.mit.edu)

Dr Cristina Dye, a lecturer in child language development, found that two to three- year-olds are using grammar far sooner than expected.

She studied fifty French speaking youngsters aged between 23 and 37 months, capturing tens of thousands of their utterances.

Dr Dye, who carried out the research while at Cornell University in the United States, found that the children were using ‘little words’ which form the skeleton of sentences such as a, an, can, is, an, far sooner than previously thought.

Dr Dye and her team used advanced recording technology including highly sensitive microphones placed close to the children, to capture the precise sounds the children voiced. They spent years painstakingly analysing every minute sound made by the toddlers and the context in which it was produced.

They found a clear, yet previously undetected, pattern of sounds and puffs of air, which consistently replaced grammatical words in many of the children’s utterances.

Dr Dye said: “Many of the toddlers we studied made a small sound, a soft breath, or a pause, at exactly the place that a grammatical word would normally be uttered.” 

“The fact that this sound was always produced in the correct place in the sentence leads us to believe that young children are knowledgeable of grammatical words. They are far more sophisticated in their grammatical competence than we ever understood.

“Despite the fact the toddlers we studied were acquiring French, our findings are expected to extend to other languages. I believe we should give toddlers more credit – they’re much more amazing than we realised.”

For decades the prevailing view among developmental specialists has been that children’s early word combinations are devoid of grammatical words. On this view, children then undergo a ‘tadpole to frog’ transformation where due to an unknown mechanism, they start to develop grammar in their speech. Dye’s results now challenge the old view.

Dr Dye said: “The research sheds light on a really important part of a child’s development. Language is one of the things that makes us human and understanding how we acquire it shows just how amazing children are.

“There are also implications for understanding language delay in children. When children don’t learn to speak normally it  can lead to serious issues later in life. For example, those who have it are more likely to suffer from mental illness or be unemployed later in life. If we can understand what is ‘normal’ as early as possible then we can intervene sooner to help those children.”

The research was originally published in the Journal of Linguistics.

(Source: ncl.ac.uk)

Researchers at the MedUni Vienna have proved in a so far unique multicenter study that clinical functional magnetic resonance tomography (fMRI), in the area in which the MedUni Vienna has a leading role internationally, is a safe method in brain surgery. With the aid of fMRI imaging can pinpoint to the millimetre where critical nerve fibres (e.g. vital for speech or hand function) lie and which have to be avoided – in operations on brain tumours for example.

"With the assistance of functional magnetic resonance tomography we are, if you like, drawing a red line for the surgeon so he knows where not to make an incision so as to avoid damage," says Roland Beisteiner from the University Department of Neurology at the MedUni Vienna. The neurologist and president of the Austrian Society for fMRI was playing a part in the development of fMRI as early as 1992, initiating its development in Austria. Since then this method has been developed and implemented at the University Department of Neurology and the High Field MRI Center of Excellence.

Now Beisteiner’s team have been able for the first time to demonstrate in a current paper in the top journal “Radiology" that functional magnetic resonance tomography provides diagnostic certainty in operations on the brain – no matter what the equipment is (whether a 7Tesla magnetic resonance tomograph as in Vienna or even only a 1.5Tesla), no matter in which location and also irrespective of who is operating it. The Medical Universities in Innsbruck and Salzburg, the Heinrich Heine University of Düsseldorf and the Stiftungsklinikum Koblenz (Koblenz Hospital Foundation) also took part in the study.

The “Imaging and Cognition Biology” Research Cluster of the MedUni and Vienna University

Likewise, with the help of functional magnetic resonance tomography, the teams of Beisteiner and Tecumseh Fitch (Faculty of Life Sciences of the University of Vienna) are investigating in a joint research cluster belonging to the MedUni Vienna and the University of Vienna whether the structural and syntactic processing of music takes place in similar areas of the brain as does the processing of speech. Says Beisteiner: “It is never exactly the same area of the brain; however, brain activities can overlap when talking or playing an instrument.”

The main focus of the research cluster is to determine precisely the common areas of the brain involved and to develop new treatments by activating them. These could perhaps then be used on people suffering from aphasia, which is a loss of language as the result of brain damage mostly to the left half of the brain.

According to Beisteiner there have been some astonishing results: “People, who could no longer speak because of their aphasia, have been able to sing the words they have learned to the matching tune.” From this one can conclude that it would seem to make sense to also practise music skills during speech therapy.

The “Imaging and Cognition Biology” research cluster is one of six joint clusters at the MedUni Vienna with the University of Vienna, which were set up in 2011. Further information: http://forschungscluster.meduniwien.ac.at/.

(Source: meduniwien.ac.at)