Closer to a cure for eczema

Scientists have found that a strain of yeast implicated in inflammatory skin conditions, including eczema, can be killed by certain peptides and could potentially provide a new treatment for these debilitating skin conditions. This research is published in the Society for Applied Microbiology’s journal, Letters in Applied Microbiology.

20% of children in the UK suffer from atopic eczema and whilst this usually clears up in adolescence, 7% of adults will continue to suffer throughout their lifetime. Furthermore, this type of eczema, characterized by dry, itchy, flaking skin, is increasing in prevalence. Whilst the cause of eczema remains unknown, one known trigger factor is the yeast Malassezia sympodialis.

This strain of yeast is one of the most common skin yeasts in both healthy individuals and those suffering from eczema. The skin barrier is more fragile and often broken in those suffering from such skin conditions, and this allows the yeast to cause infection which then further exacerbates the condition. Scientists at Karolinska Institute in Sweden looked for a way to kill Malassezia sympodialis without harming healthy human cells.

The researchers looked at the effect on the yeast of 21 peptides which had either; cell-penetrating or antimicrobial properties. Cell-penetrating peptides are often investigated as drug delivery vectors and are able to cross the cell membrane, although the exact mechanism for this is unknown. Antimicrobial peptides, on the other hand, are natural antibiotics and kill many different types of microbe including some bacteria, fungi and viruses.

Tina Holm and her colleagues at Stockholm University and Karolinska Institute, added these different peptides types to separate yeast colonies and assessed the toxicity of each peptide type to the yeast. They found that six of the 21 peptides they tested successfully killed the yeast without damaging the membrane of keratinocytes, human skin cells.

Tina commented “Many questions remain to be solved before these peptides can be used in humans. However, the appealing combination of being toxic to the yeast at low concentrations whilst sparing human cells makes them very promising as antifungal agents. We hope that these peptides in the future can be used to ease the symptoms of patients suffering from atopic eczema and significantly increase their quality of life.”

The next step will be to further examine the mechanism(s) used by the peptides to kill yeast cells, in order to develop a potential treatment for eczema and other skin conditions.

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-Health Research on Skin Conditions

Childless women ‘poorer health’

DEAKIN UNIVERSITY

“While the results of our study might not paint a rosy picture, they do not mean that childlessness is a health hazard for women." Image: diego_cervo/iStockphoto Childless women may experience poorer health and wellbeing than the general Australian female population, according to the results of a Deakin University study. Deakin health researchers examined the physical and mental health and wellbeing of 50 childless women during the latter part of their reproductive years and considered their health and wellbeing in comparison to the Australian female adult population, including women with and without children. The findings are published online atBioMed Central. The results indicate that while childless women may experience better physical functioning when compared to the Australian female adult population, they may also experience poorer general health, vitality, social functioning and mental health. “While the results of our study might not paint a rosy picture, they do not mean that childlessness is a health hazard for women,” explained Dr Melissa Graham, a researcher with Deakin’s School of Health and Social Development. “These findings may be a reflection of a number of different factors. “Poorer health among childless women may mean they are less likely to have children, rather than their poor health being a result of their childlessness. “Distinguishing health and wellbeing according to women’s reasons for childlessness is also important however our current study sample was too small to do this.” Dr Graham suggests that the health of childless women may be compromised by the pressures placed on women to become mothers. “Australia is predominantly a society where motherhood is encouraged,” Dr Graham said. “This is despite an increase in the number and proportion of women remaining childless. “Our previous research, along with that by others, with women who did not have children suggested that childlessness is perceived predominantly negatively and this may have consequences for the health of childless women. “If childlessness was reframed as a natural and familiar way of being the apparent negative health consequences of being a childless woman may be addressed. “Childlessness should be accepted as an appropriate outcome of adult life for women and motherhood should not be the only valued position.” The Deakin researchers are now looking to undertake a larger scale study to more fully understand how women come to be childless, their experiences of marginalisation, stigmatisation and social exclusion, and their health and wellbeing. “While motherhood has been the focus of much research, little is known about the health and wellbeing of women who do not have children,” Dr Graham said. “By better understanding childless women’s health and wellbeing we will be better able to ensure that their health needs are being meet both now and into the future.” About the study Most women in the study were in a relationship with 42 per cent married and 32 per cent currently not in a relationship. Almost half the women (46.7 per cent) did not wish to have children and 11.1 per cent identified themselves or their partner as infertile. Women in this study reported poorer general health, vitality, social functioning and mental health when compared to the female population. However, these women also reported better physical functioning than for the female adult population. The researchers also found that there was no difference in these women’s body mass index, fruit consumption or smoking when compared to the female adult population. However, childless women in this study were almost 12 per cent more likely to consume five serves of vegetables per day than the female population. Editor's Note: Original news release can be found here.

New hope for Cystic fibrosis

MARION LOPEZ, SCIENCENETWORK WA

The Lung Institute of WA (LIWA) has recently made a breakthrough in the search for a drug to improve the quality of life of patients with Cystic Fibrosis (CF). A debilitating disease, CF is an inherited defect in a gene called CFTR (or Cystic Fibrosis Transmembrane Conductance Regulator) that codes for a complex protein involved in moving salt (Na and Cl) at cell surfaces. According to LIWA’s Director Professor Phil Thompson, the gene anomaly leads to defective mucus in the airways (stickier) and also in the pancreas affecting digestion of food and sweat glands. “In the lung, this leads to recurrent infections, airway wall damage as well as inflammation, and leads to chronic lung disease resulting in early death,” he says. “The gene has many mutations and this leads to the various names such as G551D and F508del. “Some mutations cause greater severity of abnormality than others.” The new drug treatment (VX-770), whose study results have been published in the New England Journal of Medicine, works by reversing the genetic abnormality in the CF mutation G551D. The results showed a significant and sustained improvement in lung function, a lower rate in pulmonary exacerbations and a reduction in sweat chloride and weight gain. Perth man Ernie Bindel was diagnosed with CF mutation G551D and has been on the trialed drug for over a year. He talks about the positive impact the medication has had on his condition.   "This is the longest period I have remained out of hospital in my life,” he says. “Over all I feel better, cough less and can take part in more physical activities.   "Another positive is that no needles were involved and the orally administered drug was quicker and easier to take than the intravenous injection."   LIWA’s positive results encouraged the search for a drug treatment for F508del, the most common CF mutation which affects about 300 CF patients in WA. LIWA is currently recruiting patients with the mutation to assess the drug VX-809, hoping the results will be similar to those experienced with mutation G551D. Individuals over the age of 18 with CF who are interested in participating in the new trial should contact LIWA at 9346 3198 or admin@liwa.uwa.edu.au for further information. Editor's Note: Original news release can be found here.

Oxygen ‘2.48 billion years old’

GEOFF VIVIAN, SCIENCENETWORK WA

The research group dates the Great Oxidation Event at between 2.48 and 2.32 billion years ago. Image: davidf/iStockphoto Banded ironstone core samples from the Pilbara have aided in dating the first appearance of atmospheric oxygen at 2.48 billion years ago. UWA Associate Professor Mark Barley says the theory—published in the journal Nature by Prof Barley and his colleagues—rested on the reliability of the rock samples they used as evidence. Prof Barley is one of a group of geobiologists that date the Great Oxidation Event, when earth’s atmospheric oxygen formed, at between 2.48 and 2.32 billion years ago. He says the groups’ argument depended on pinpointing the time that chromium—previously bonded in igneous rocks—began to appear in the ocean’s waters. “This was evidence for the most primitive form of aerobic respiring life, aerobic respiring bacteria which oxidise pyrite that released acid that dissolved rocks and soils on land, including chromium, that was then carried to the oceans by the flow of water,” Prof Barley says. “The aerobic respiring chemolitho-autorobic bacteria require coexistence with cyanobacteria producing oxygen to do this.” The advent of breathable oxygen had been previously dated at 2.7 billion years BP—at date Prof Barley said comes from unreliable data. He says rocks of that age are often “overprinted” by data from later metamorphic processes. “The banded iron formations have good representation of the geochemistry in the earth’s early ocean, but also a lot of [the formations] were later altered,” he says. “The later changing of banded iron formations into iron ores happened after the main event of oxidation. Prof Barley says geobiologists are working towards a better database, for more evidence of when the types of bacteria linked to the rise of oxygen were really functioning. “We got a good group of samples from banded iron formations and analysed the chromium isotopes and other elements because that gives the strongest evidence of oxidation,” he says. “If you have a good deep drill hole that’s not close to a big iron ore deposit, you have got the appropriate chemistry record.” Dr Barley says he contributed core samples of banded ironstone that he obtained from the Pilbara. “I added some key samples to gaps in the global database,” he says. Dr Barley says this analysis provided no evidence of dissolved chromium in the oceans older than 2.48 billion years, and therefore no evidence of atmospheric oxygen. Editor's Note: Original news release can be found here.

Running Free

“The need of the spirit soul is that he wants to get out of the limited sphere of material bondage and fulfill his desire for complete freedom. He wants to get out of the covered walls of the greater universe. He wants to see the free light and the spirit. That complete freedom is achieved when he meets the complete spirit, the Personality of Godhead.” (Shrila Prabhupada, Shrimad Bhagavatam, 1.2.8 Purport) Like a lion chasing after an elephant, the cows    are quickly running after their caretaker, their very life breath, the soul of their fortunes, the keeper of their heart, the beloved child of Mother Yashoda and Nanda Maharaja. Whereas the lion looks to pounce, these cows simply crave association, another glance at the beauty of Shyamasundara   , the enchanting youth with a blackish complexion who holds a flute in His hands and wears a peacock feather in His hair. The cows, deer, butterflies, and every other living resident cannot get enough of this vision. Every time the young child looks at them, their attachment increases even more. What then to speak of when He plays His flute? The sound is so intoxicating that the barriers imposed by the body become too inhibiting, for how could any form ever contain the loving feelings waiting to burst out from the liberated spirit soul? The only proper release for this love is through continuous running on the wonderful field, soaking up the beautiful vision and sweet sounds that belong to Shri Krishna, the most intimate friend of the spirit soul. More than just dogmatic insistence or reliance on rules and regulations of scriptures, the point to spirituality, a discipline that instills a regimen of dedicated activity, is to meet the needs of the soul. Only when one is in ignorance of these needs will they consider the postulates and truths presented by the oldest tradition of spiritual values, the Vedas, to be dogmatic, sectarian, sentimentalist, or mythological. Everything is pieced together perfectly in the Vedic texts to allow the soul to ultimately run free with transcendental love, to let its brightness of knowledge, eternality, and blissfulness shine everywhere. Those who are fortunate enough to follow the prescriptions presented by the authorized followers of the Vedas, those who are liberated from the inhibiting effects of matter, will be able to taste the fruit of their existence. While in the premature assessment the Vedas are taken to be a set of written words, they are actually not different from the person they describe and glorify. The Vedas sing the glories of the Supreme Personality of Godhead. The songs fulfill the same purpose as the many aphorisms, stories of historical events, and poems and descriptions found in the vast literature that follows the original Vedas, a set of information passed down by the Supreme Person Himself. The glorification of God serves to give pleasure both to the hearer and to the worshiping person. This glorification lines up with the qualities of the spirit soul, the essence of identity. Though it’s a difficult concept to grasp, we will continue to live after death. We can take this as fact because our own body has undergone constant change since as far back as we can remember. Do you know that you once survived in the tiniest of spaces within the womb of your mother? You don’t remember this experience, but you understand from the statements of your parents and the direct perception of external events that this definitely happened. How in the world did you survive? You lived in the womb for nine months, and prior to that you had to be somewhere else. From the experience in the womb you also know that just because you don’t remember something doesn’t mean that it didn’t happen. “As the embodied soul continually passes, in this body, from boyhood to youth to old age, the soul similarly passes into another body at death. The self-realized soul is not bewildered by such a change.” (Lord Krishna   , Bhagavad-gita   , 2.13) What happened to that form that survived in the womb? Can we ever get it back? The Vedas shed light on these issues, with the most concise and complete explanation provided by Krishna Himself in the Bhagavad-gita, one of the widest read religious texts in history. The soul is so small that it can survive within even the form of an ant. Basically anything that we consider to be a life form has spirit inside of it. Indeed the absence of spirit, its departure from a particular form, is what causes death. If you leave a particular room, does that mean your existence is finished? To the occupants of the room you may no longer exist, but you know that you’re only travelling somewhere else, with your identity remaining intact. Birth and death are similar travels, where the spirit soul either enters a new dwelling or gives one up in favor of a new one. The truths about the soul are presented in the beginning to the aspiring transcendentalist of the Vedic tradition because they form the knowledgebase from which one can launch into higher topics. What higher topics could there be? Apprised of the travels of the soul, the obvious next question is why there must be birth and death in the first place. Moreover, why are there different forms? The constitutional position of the soul is what matters. The individual spirit gets placed into different bodies based on desire and work, which operate collectively under karma. The duties prescribed to a particular human being make up their karma, and the reactions that follow are referred to as karma-phala, or the fruits of action. Not all fruits taste the same, nor do they manifest at the same rate. A tomato plant may not grow as quickly as another plant, but this doesn’t mean that the reactions to the work applied during the planting stage don’t arrive. “Krishna had actually entered the cave to deliver King Muchukunda from his austerity, but He did not first appear before him. He arranged that first Kalayavana should come before him. That is the way of the activities of the Supreme Personality of Godhead; He does one thing in such a way that many other purposes are served. He wanted to deliver King Muchukunda, who was sleeping in the cave, and at the same time He wanted to kill Kalayavana, who had attacked Mathura City. By this action He served all purposes.” (Krishna, The Supreme Personality of Godhead   , Vol 1, Ch 50) The Supreme Lord sequences everything together perfectly so that rewards arrive just when they are supposed to. The spirit soul, however, is transcendental to every reaction, for it doesn’t even remain tied to its body forever. If we live in a room for only a short time, we can’t say that anything within it forms the basis of our identity. Since God manages the laws of spirit and matter, every spiritual being is inherently tied to Him. The link to God is a loving one. This loving propensity is the very dharma of the soul, its essential characteristic. The soul’s dharma can never be removed, but it can be masked. The various bodies assumed mask the loving propensity of the soul to one degree or another. It is seen in life that some people are violent haters while others are always peaceful and kind to the people they meet. The loving propensity is responsible for both behaviors. If not for strong attachment, there would be no chance for intense feelings of anger, betrayal, or neglect to result from the interaction with other living beings. Love is the root cause of every emotion. In the various material bodies assumed, the loving propensity cannot be housed properly, due especially to the inhibiting nature of material elements. If we don’t know who we are supposed to love, how will we ever properly project our energy? It’s like having a fire extinguisher that points in every direction except towards the actual fire. The fire extinguisher will still work, i.e. it will still dissipate the ingredients necessary to put out a fire, but if the flow of energy is not directed in the proper area, the output goes to waste. With the living being, the output of energy continues in a perpetual cycle until eventually the proper target is identified. This can take many lifetimes, for even a person who realizes the need for self-realization, which includes understanding the properties of spirit and the need for following a spiritual discipline, is considered fortunate. This should make sense, for how many people do we know who actually make loving God their primary business in life? They may believe in God and follow religious principles, but the primary thought processes within their mind, i.e. their consciousness, will be monopolized by pursuits for material sense gratification. “The individual soul in the body of a baby cannot show the full power and potency of a grown man, but the Supreme Personality of Godhead Krishna, even when lying on the lap of His mother as a baby, could exhibit His full potency and power by killing Putana and other demons who tried to attack Him. Therefore the spiritual potency of the Supreme Personality of Godhead is said to be eka-rasa, or without change.” (Shrila Prabhupada   , Krishna, the Supreme Personality of Godhead, Vol 2, Ch 32) The body can be likened to a holding cell, a container that limits the exercise of ability of the spirit soul. Based on the variety in species, we know that the soul is capable of doing so many things. A soul can fly through the air, live within the water, do complex mathematics, sing beautifully, write wonderful poetry, live within the ground, and even stand erect for thousands of years. Yet none of these abilities extract even a smidgen of the full potential for action that exists within spirit. How do we break free then? Think of being pumped up, extremely enthusiastic for action. Imagine never requiring sleep or being alert even while resting. This is how the liberated souls feel, for they have found the proper target for the loving emotions from within that never exhaust. The ideal beneficiary is Krishna, or God. For the loving emotions to continually flow, it would make sense that Krishna would have to be extremely attractive. If something does not elicit heartfelt emotional responses upon contact, how could service continue? We know how liberated souls behave based on the documented historical evidence presented by Vedic literature. The qualities and activities of countless great souls, or mahajanas, are described in these wonderful works. Though Krishna is the fountainhead of all spiritual manifestations and loving Him is the constitutional position of the soul, this doesn’t mean that all liberated souls behave the same way. Rather, there are multifarious outlets for the loving propensity found within spirit. Some worship God by chanting    His names, “Hare Krishna Hare Krishna, Krishna Krishna, Hare Hare, Hare Rama Hare Rama, Rama Rama, Hare Hare   ”. Others follow their prescribed duties and keep the Lord’s vision within their minds. Some take up direct service to Him, acting like menial servants who are entirely invested in the outcome of events so that their beloved Lord will be pleased. Some act as Krishna’s friend, while others love Him very intimately. Some derive pleasure through contact with His soft skin, while others delight in just hearing about Him. This last method is the best way to unlock the dormant love for God that everyone has resting inside of them. The hearing process dissipates the nescience surrounding the pure soul and leads to further interaction with the Supreme Lord. Even those who have personally offered service to God delight in hearing about Him. If the Vedic literature available to them is not cutting it, if it doesn’t have enough information to satisfy them, these souls will write their own poems and songs, filling the mind with thoughts about Krishna; thereby fostering Krishna consciousness, which is the very definition of liberation   . Devotional service   , or bhakti-yoga, is like playing on an open field, where there are no walls to stop the soul wanting to run to Krishna’s side. This analogy works both figuratively and literally. During Krishna’s time on earth some five thousand years ago, His closest friends would play with Him on the fields ofVrindavana   . In this pristine environment, the cows and other animals were well protected. The cowherd boys had fun daily, for they were in Krishna’s company. Even the women and caretakers derived pleasure from doing their routine work, for they had Krishna by their side. Many thousands of years prior to that, a group of extra hyper monkeys got to run free in the forests and travel to distant lands to offer service to God in His avatara    as a warrior prince named Rama. These Vanaras got to scour the earth to look for Rama’s wife Sita. They built a bridge made of stones to Lanka where Sita was being held captive. They had the chance to use uprooted trees and rocks as weapons in a violent war against the Rakshasas of Lanka, who were headed by Ravana, the evil king who had tried to take Sita away for himself. The Vanaras were in the bodies of lowly monkeys, but their service was offered nonetheless. It was performed without motivation and without interruption. This means that even after Ravana was defeated, the Vanara devotees   , of whom Hanuman    was chief, continued to love God. Though the Lord eventually went back to the spiritual world of Vaikuntha, the same devotees continued to derive great pleasure just by hearing about Rama and His glories. The chance to hear about God is the very purpose of the Ramayana   , the poem authored by Maharishi Valmiki    which describes Rama’s life and pastimes. Every living entity has a choice. Either continue the process of elimination, whereby one engagement after another is indulged in until the right target for the soul’s loving propensity is hopefully found, or take to bhakti-yoga right away. The flaw with the former option is that forgetfulness creeps in. This means that some engagement that we previously renounced due to boredom will be repeated later on once the past experiences are forgotten. It’s like chewing a stick of gum, spitting it out once the taste is gone, doing something else for a while, and then going back and picking up the same chewed gum. With bhakti-yoga, the effects are not the same. Rather, the more one chants Krishna’s names and hears about His pastimes, the more attached they become to the process; the enjoyment they derive from thinking about God increases. The levels of transcendental ecstasy rise to the point that the liberated soul will settle for nothing less than serving their beloved throughout the day, not worrying about the limits imposed by material nature. The meeting with the Supreme Lord is destined to take place once this state of full Krishna consciousness is attained, for in the spiritual world there are no barriers. Matter, time and space do exist in Krishna’s realm, but their negative influence is absent; hence they are practically unrecognizable. The liberated spirit soul runs to where Krishna is, and once they find Him, they never let Him go. Should He run away again, they continue to follow, thus allowing their inexhaustible reservoir of love to continually pour out, keeping the soul in perpetual ecstasy. In Closing: The bonds of material nature constrict, The loving nature of spirit they restrict. Take one engagement after another, To find a state of bliss like no other. That can only be found in Krishna’s company, Connect with Him through ways that are many. Chant His names or glories do you sing, Or offerings of prasadam to Him bring. Whatever the method follow it with faith, Let your soul free and arrive at heaven’s gate.

Playing music alters the processing of multiple sensory stimuli in the brain

 

 

A segment of the audiovisual speech (left) and music (right) stimulus. © HweeLing Lee/MPI for Biological Cybernetics

(Medical Xpress) -- Over the years pianists develop a particularly acute sense of the temporal correlation between the movements of the piano keys and the sound of the notes played. However, they are no better than non-musicians at assessing the synchronicity of lip movements and speech.

This was discovered by researchers from the Max Planck Institute for Biological Cybernetics in a comparative study on the simultaneous brain processing of stimuli from different senses by musicians and non-musicians. The researchers also used functional magnetic resonance imaging in their study to map the areas of the brain active during this process. According to their findings, in pianists, the perception of asynchronous music and hand movements triggers increased error signals in a circuit involving the cerebellum, premotor and associative areas of the brain, which is refined by piano practicing. The study shows that our sensorimotor experience influences the way in which the brain temporally links signals from different senses during perception.

In a world full of stimuli which affect all senses, the human brain constantly has to link the impressions we perceive in a way that makes sense. We learn through experience, for example, that the synchronous events that arise in a busy bar setting, such as the lip movements of a particular person and the sound of a certain voice, belong together. HweeLing Lee and research group leader Uta Noppeney from the Max Planck Institute for Biological Cybernetics in Tübingen study how the brain integrates stimuli from several senses and how the circuits in the brain change as a result of learning. In their latest study, they examined how well 18 amateur pianists were able to perceive the temporal coincidence between finger movements on the piano keys and a piece of piano music and between lip movements and spoken sentences as compared with 19 non-musicians. “For this study, we availed of the fact that the pianists specifically train in an activity, in which several sensory stimuli, that is visual and auditory information, movement and the striking of the piano keys, have to be connected,” explains Uta Noppeney.

During the experiment, the finger or mouth movements were advanced or delayed in relation to the sounds heard at intervals of up to 360 milliseconds. The study participants were requested to specify when asked whether the events were synchronous or asynchronous. Using the same film and sound material and the same participants, the experiments were then repeated using functional magnetic resonance imaging (fMRI). In this case, the subjects remained passive and the machine recorded the areas of the brain that became active during the automatic perception of the synchronous and asynchronous signals.

The experiments revealed that the pianists were significantly more accurate than the non-musicians in assessing whether the finger movements on the piano and the sounds heard coincided temporally or not. “The window for the temporal integration of the stimuli in the pianists is clearly narrower than in non-musicians,” says HweeLing Lee. However, the same differences were not observed in the experiments involving spoken sentences and lip movements – both groups recorded similar performances here. In principle, asynchronicity in language and music activates the same areas in the brain. However, the fMRI scans showed that, in the experiment with the pianists, asynchronous music triggered a stronger signal in a circuit involving the left cerebellum, a premotor and associative region in the cerebral cortex than in the non-musicians.

“The processing of stimuli in the brains of the pianists points to a context-specific mechanism: as a result of their piano practice, a forward model involving the cerebellum and premotor cerebral cortex is programmed in the circuit which enables the individual to make far more precise predictions about the correct temporal sequence of the visual and auditory signals,” explains Uta Noppeney. “An asynchronous stimulus triggers prediction error signal.” The researchers see this as an important indication of how the brain can generally react in a flexible way to sensorimotor experience. Whether pianists would perform equally well in the assessment of violin music and whether more intensive music playing would influence language processing in the brain remain open questions. “For the next stage in the study of the processing of multiple sensory stimuli in the brain, we will have to train the participants in a specific way so that we can investigate the effects in greater detail,” says Uta Noppeney.

More information: HweeLing Lee, Uta Noppeney, Long-term music training tunes how the brain temporally binds signals from multiple senses,PNAS, doi: 10.1073/pnas.1115267108

 

Provided by Max-Planck-Gesellschaft

"Playing music alters the processing of multiple sensory stimuli in the brain." November 24th, 2011. http://medicalxpress.com/news/2011-11-music-multiple-sensory-stimuli-brain.html

 

Posted by
Robert Karl Stonjek

How the brain strings words into sentences

Using magnetic resonance imaging of the brain, researchers can visualise the two main language processing regions, Broca's (yellow) and Wernicke's (purple) regions. (Image: Stephen Wilson)

(Medical Xpress) -- Researchers have discovered that Distinct neural pathways are important for different aspects of language processing, studying patients with language impairments caused by neurodegenerative diseases.

While it has long been recognised that certain areas in the brain's left hemisphere enable us to understand and produce language, scientists are still figuring out exactly how those areas divvy up the highly complex processes necessary to comprehend and produce language.

Advances in brain imaging made within the last 10 years have revealed that highly complex cognitive tasks such as language processing rely not only on particular regions of the cerebral cortex but also on the white matter fibre pathways that connect them.

"With this new technology, scientists started to realise that in the language network, there are a lot more connecting pathways than we originally thought," said Stephen Wilson, who recently joined the University of Arizona's Department of Speech, language and Hearing Sciences as an assistant professor. "They are likely to have different functions because the brain is not just a homogeneous conglomerate of cells, but there hasn't been a lot of evidence as to what kind of information is carried on the different pathways."

Working in collaboration with his colleagues at the UA, the Department of Neurology at the University of California, San Francisco and the Scientific Institute and University Hospital San Raffaele in Milan, Italy, Wilson discovered that not only are the connecting pathways important for language processing, but they specialise in different tasks.

Two brain areas called Broca's region and Wernicke's region serve as the main computing hubs underlying language processing, with dense bundles of nerve fibers linking the two, much like fiber optic cables connecting computer servers. But while it was known that Broca's and Wernicke's region are connected by upper and a lower white matter pathways, most research had focused on the nerve cells clustered inside the two language-processing regions themselves.

Working with patients suffering from language impairments because of a variety of neurodegenerative diseases, Wilsons' team used brain imaging and language tests to disentangle the roles played by the two pathways. Their findings are published in a recent issue of the scientific journal Neuron.

"If you have damage to the lower pathway, you have damage to the lexicon and semantics," Wilson said. "You forget the name of things, you forget the meaning of words. But surprisingly, you're extremely good at constructing sentences."

Assistant professor Stephen Wilson studies how the brain processes language by combining brain imaging with performance-based language tests. (Photo: D. Stolte/UANews)

"With damage to the upper pathway, the opposite is true; patients name things quite well, they know the words, they can understand them, they can remember them, but when it comes to figuring out the meaning of a complex sentence, they are going to fail."

The study marks the first time it has been shown that upper and lower tracts play distinct functional roles in language processing, the authors write. Only the upper pathway plays a critical role in syntactic processing.

Wilson collected the data while he was a postdoctoral fellow working with patients with neurodegenerative diseases of varying severity, recruited through the Memory and Aging Center at UCSF. The study included 15 men and 12 women around the age of 66.

Unlike many other studies investigating acquired language disorders, which are called aphasias and usually caused by damage to the brain, Wilson's team had a unique opportunity to study patients with very specific and variable degrees of brain damage.

"Most aphasias are caused by strokes, and most of the strokes that affect language regions probably would affect both pathways," Wilson said. "In contrast, the patients with progressive aphasias who we worked with had very rare and very specific neurodegenerative diseases that selectively target different brain regions, allowing us to tease apart the contributions of the two pathways."

To find out which of the two nerve fiber bundles does what in language processing, the team combined magnetic resonance brain imaging technology to visualize damaged areas and language assessment tasks testing the participants' ability to comprehend and produce sentences.

"We would give the study participants a brief scenario and ask them to complete it with what comes naturally," Wilson said. "For example, if I said to you, ‘A man was walking along the railway tracks. He didn't hear the train coming. What happened to the man?' Usually, you would say, ‘He was hit by the train,' or something along those lines."

"But a patient with damage to the upper pathway might say something like 'train, man, hit.' We found that the lower pathway has a completely different function, which is in the meaning of single words."

To test for comprehension of the meaning of a sentence, the researchers presented the patient with a sentence like, "The girl who is pushing the boy is green," and then ask which of the two pictures depicted that scenario accurately.

"One picture would show a green girl pushing a boy, and the other would show a girl pushing a green boy," Wilson said. "The colors will be the same, the agents will be the same, and the action is the same. The only difference is, which actor does the color apply to?"

"Those who have only lower pathway damage do really well on this, which shows that damage to that pathway doesn't interfere with your ability to use the little function words or the functional endings on words to figure out the relationships between the words in a sentence."

Wilson said that most previous studies linking neurodegeneration of specific regions with cognitive deficits have focused on damage to gray matter, rather than the white matter that connects regions to one another.

"Our study shows that the deficits in the ability to process sentences are above and beyond anything that could be explained by gray matter loss alone," Wilson added. "It is the first study to show that damage to one major pathway more than then other major pathway is associated with a specific deficit in one aspect of language."

More information: http://www.cell.co … 11%2900835-X

 

Provided by University of Arizona

"How the brain strings words into sentences." November 24th, 2011. http://medicalxpress.com/news/2011-11-brain-words-sentences.html

 

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Robert Karl Stonjek