Distinct neural pathways are important for different aspects of language processing, researchers have discovered, studying patients with language impairments caused by neurodegenerative diseases

While it has long been recognized 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 fiber pathways that connect them. "With this new technology, scientists started to realize 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 specialize 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. 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."

Babies and children are whizzes at learning a second language, but that ability begins to fade as early as their first birthdays. Researchers at the University of Washington's Institute for Learning & Brain Sciences are investigating the brain mechanisms that contribute to infants' prowess at learning languages, with the hope that the findings could boost bilingualism in adults, too.

In a new study, the researchers report that the brains of babies raised in bilingual households show a longer period of being flexible to different languages, especially if they hear a lot of language at home. The researchers also show that the relative amount of each language – English and Spanish – babies were exposed to affected their vocabulary as toddlers.

The study, published online Aug. 17 in Journal of Phonetics, is the first to measure brain activity throughout infancy and relate it to language exposure and speaking ability. "The bilingual brain is fascinating because it reflects humans' abilities for flexible thinking – bilingual babies learn that objects and events in the world have two names, and flexibly switch between these labels, giving the brain lots of good exercise," said Patricia Kuhl, co-author of the study and co-director of the UW's Institute for Learning & Brain Sciences.

Kuhl's previous studies show that between 8 and 10 months of age, monolingual babies become increasingly able to distinguish speech sounds of their native language, while at the same time their ability to distinguish sounds from a foreign language declines. For instance, between 8 and 10 months of age babies exposed to English become better at detecting the difference between "r" and "l" sounds, which are prevalent in the English language. This is the same age when Japanese babies, who are not exposed to as many "r" and "l" sounds, decline in their ability to detect them.

"The infant brain tunes itself to the sounds of the language during this sensitive period in development, and we're trying to figure out exactly how that happens," said Kuhl, who's also a UW professor of speech and hearing sciences. "But almost nothing is known about how bilingual babies do this for two languages. Knowing how experience sculpts the brain will tell us something that goes way beyond language development."

In the current study, babies from monolingual (English or Spanish) and bilingual (English and Spanish) households wore caps fitted with electrodes to measure brain activity with an electroencephalogram, or EEG, a device that records the flow of energy in the brain. Babies heard background speech sounds in one language, and then a contrasting sound in the other language occurred occasionally. For example, a sound that is used in both Spanish and English served as the background sound and then a Spanish "da" and an English "ta" each randomly occurred 10 percent of the time as contrasting sounds. If the brain can detect the contrasting sound, there is a signature pattern called the mismatch response that can be detected with the EEG.

Monolingual babies at 6-9 months of age showed the mismatch response for both the Spanish and English contrasting sounds, indicating that they noticed the change in both languages. But at 10-12 months of age, monolingual babies only responded to the English contrasting sound. Bilingual babies showed a different pattern. At 6-9 months, bilinguals did not show the mismatch response, but at 10-12 months they showed the mismatch for both sounds. This suggests that the bilingual brain remains flexible to languages for a longer period of time, possibly because bilingual infants are exposed to a greater variety of speech sounds at home.

This difference in development suggests that the bilingual babies "may have a different timetable for neurally committing to a language" compared with monolingual babies, said Adrian Garcia-Sierra, lead author and a postdoctoral researcher at UW's Institute for Learning & Brain Sciences. "When the brain is exposed to two languages rather than only one, the most adaptive response is to stay open longer before showing the perceptual narrowing that monolingual infants typically show at the end of the first year of life," Garcia-Sierra said.

To see if those brain responses at 10-12 months related to later speaking skills, the researchers followed up with the parents when the babies were about 15 months old to see how many Spanish and English words the children knew. They found that early brain responses to language could predict infants' word learning ability. That is, the size of the bilingual children's vocabulary was associated with the strength of their brain responses in discriminating languages at 10-12 months of age.

Early exposure to language also made a difference: Bilingual babies exposed to more English at home, including from their parents, other relatives and family friends, subsequently produced more words in English. The pattern held true for Spanish. The researchers say the best way for children to learn a second language is through social interactions and daily exposure to the language. "Learning a second language is like learning a sport," said Garcia-Sierra, who is raising his two young children as bilingual. "The more you play the better you get."

What a difference culture makes.

Most of the linguistic functions in humans are controlled by the left cerebral hemisphere. A study of captive chimpanzees at the Yerkes National Primate Research Center (Atlanta, Georgia), reported in the January 2010 issue of Elsevier's Cortex, suggests that this "hemispheric lateralization" for language may have its evolutionary roots in the gestural communication of our common ancestors. A large majority of the chimpanzees in the study showed a significant bias towards right-handed gestures when communicating, which may reflect a similar dominance of the left hemisphere for communication in chimpanzees as that seen for language functions in humans.

A team of researchers, supervised by Prof. William D. Hopkins of Agnes Scott College (Decatur, Georgia), studied hand-use in 70 captive chimpanzees over a period of 10 months, recording a variety of communicative gestures specific to chimpanzees. These included 'arm threat', 'extend arm' or 'hand-slap' gestures produced in different social contexts, such as attention-getting interactions, shared excitation, threat, aggression, greeting, reconciliation or invitations for grooming or for play. The gestures were directed at the human observers, as well as toward other chimpanzees.

"The degree of predominance of the right hand for gestures is one of the most pronounced we have ever found in chimpanzees in comparison to other non-communicative manual actions. We already found such manual biases in this species for pointing gestures exclusively directed to humans. These additional data clearly showed that right-handedness for gestures is not specifically associated to interactions with humans, but generalizes to intraspecific communication", notes Prof. Hopkins.

The French co-authors, Dr. Adrien Meguerditchian and Prof. Jacques Vauclair, from the Aix-Marseille University (Aix-en-Provence, France), also point out that "this finding provides additional support to the idea that speech evolved initially from a gestural communicative system in our ancestors. Moreover, gestural communication in apes shares some key features with human language, such as intentionality, referential properties and flexibility of learning and use".

Many of us learn a foreign language when we are young, but in some cases, exposure to that language is brief and we never get to hear or practice it subsequently. Our subjective impression is often that the neglected language completely fades away from our memory. But does "use it or lose it" apply to foreign languages? Although it may seem we have absolutely no memory of the neglected language, new research suggests this "forgotten" language may be more deeply engraved in our minds than we realize.

Psychologists Jeffrey Bowers, Sven L. Mattys, and Suzanne Gage from the University of Bristol recruited volunteers who were native English speakers but who had learned either Hindi or Zulu as children when living abroad. The researchers focused on Hindi and Zulu because these languages contain certain phonemes that are difficult for native English speakers to recognize. A phoneme is the smallest sound in a language—a group of phonemes forms a word.

The scientists asked the volunteers to complete a background vocabulary test to see if they remembered any words from the neglected language. They then trained the participants to distinguish between pairs of phonemes that started Hindi or Zulu words.

As it turned out, even though the volunteers showed no memory of the second language in the vocabulary test, they were able to quickly relearn and correctly identify phonemes that were spoken in the neglected language.

These findings, which appeared in a recent issue of Psychological Science, a journal of the Association for Psychological Science, suggest that exposing young children to foreign languages, even if they do not continue to speak them, can have a lasting impact on speech perception. The authors conclude, "Even if the language is forgotten (or feels this way) after many years of disuse, leftover traces of the early exposure can manifest themselves as an improved ability to relearn the language."

Scientific American -- Science Talk
(6 February 2008)

In this episode, University of California, Berkeley, linguist Alice Gaby talks about the relationships among language, culture, cognition and perception.

9 December 2007 — You study the menu at a restaurant and decide to order the steak rather than the salmon. But when the waiter tells you about the lobster special, you decide lobster trumps steak. Without reconsidering the salmon, you place your order—all because of a trait called “transitivity.”

“Transitivity is the hallmark of rational economic choice,” says Camillo Padoa-Schioppa, a postdoctoral researcher in HMS Professor of Neurobiology John Assad’s lab. According to transitivity, if you prefer A to B and B to C, then you ought to prefer A to C. Or, if you prefer lobster to steak, and steak to salmon, then you will prefer lobster to salmon.

Padoa-Schioppa is lead author on a paper that suggests this trait might be encoded at the level of individual neurons. The study, which appears online Dec. 9 in Nature Neuroscience, shows that some neurons in a part of the brain called the orbitofrontal cortex encode economic value in a “menu invariant” way. That is, the neurons respond the same to steak regardless if it’s offered against salmon or lobster.

“People make choices by assigning values to different options. If the values are menu invariant preferences will be transitive. The activity of these neurons does not vary with the menu options, suggesting that these neurons could be responsible for transitivity,” Padoa-Schioppa explains.

“This study provides a key insight into the biology of our frontal lobes and the neural circuits that underlie decision-making,” Assad adds. “Despite the maxim, we in fact can compare apples to oranges, and we do it all the time. Camillo’s research sheds light on how we make these types of choices.”

Frontal lobe damage has been linked to “choice deficits” such as eating disorders, compulsive gambling and abnormal social behavior. For example, in the first documented case of brain injury impacting behavior, the infamous railroad construction foreman Phineas Gage became unsociable after a tamping iron passed through his skull in 1848, damaging his frontal lobes. This area of the brain has also been implicated in drug abuse.

Labs are just beginning to probe normal decision-making at the level of individual neurons, venturing into a new field called neuroeconomics. Such research might eventually help to explain choice deficits associated with frontal lobe functions.

The new study builds on an April 2006 Nature paper in which Padoa-Schioppa and Assad identified neurons that encode the value macaque monkeys assign to juice they choose independent of its type, providing a common currency of comparison for the brain.

In that study, the scientists found that although monkeys generally prefer grape juice to apple juice, sometimes they choose the latter, if it is offered in large amounts. When presented with 3 units of apple juice and 1 unit of grape juice, for example, a monkey might take the grape juice only 50 percent of the time. This indicates that the value of the grape juice is 3 times that of the apple juice. A particular group of neurons in the orbitofrontal cortex fire at roughly the same rate, regardless of the monkey’s decision because the animal values both choices equally. These neurons also fire at the same rate if the monkey chooses 6 units of apple juice or 2 units of grape juice. Thus, these neurons encode the value the monkey receives in each trial.

Now, by adding a third juice to the mix, the team has tested whether these neurons reflect transitivity. The three juices were offered to a monkey in pairs dozens of times over the course of a session, the quantity of each juice varying from trial to trial.

In general, monkeys preferred 1 unit of juice A to 1 unit of juice B, 1B to 1C, and 1A to 1C. During each session, Padoa-Schioppa recorded the activity of a handful of neurons in the orbitofrontal cortex, and he discovered their firing rate did not depend on whether B was offered against A or against C, indicating that these neurons respond in a menu invariant way.

“The stability of these neurons could help to explain why we make decisions that are consistent over the short term,” Padoa-Schioppa says. “In our study, the neural circuit was not influenced by the short-term behavioral context.”

Padoa-Schioppa is now examining the possibility that value-encoding neurons may adapt to different value scales over longer periods of time.

Why does putting our feelings into words - talking with a therapist or friend, writing in a journal - help us to feel better? A new brain imaging study by UCLA psychologists reveals why verbalizing our feelings makes our sadness, anger and pain less intense. [complete press release from UC News Wire]

BOSTON, MA — The editors of the American Heritage® dictionaries have compiled a list of 100 words they recommend every high school graduate should know.

"The words we suggest," says senior editor Steven Kleinedler, "are not meant to be exhaustive but are a benchmark against which graduates and their parents can measure themselves. If you are able to use these words correctly, you are likely to have a superior command of the language."

The following is the entire list of 100 words:

abjure abrogate abstemious acumen antebellum auspicious belie bellicose bowdlerize chicanery chromosome churlish circumlocution circumnavigate deciduous deleterious diffident enervate enfranchise epiphany equinox euro evanescent expurgate facetious fatuous feckless fiduciary filibuster gamete gauche gerrymander hegemony hemoglobin

homogeneous hubris hypotenuse impeach incognito incontrovertible inculcate infrastructure interpolate irony jejune kinetic kowtow laissez faire lexicon loquacious lugubrious metamorphosis mitosis moiety nanotechnology nihilism nomenclature nonsectarian notarize obsequious oligarchy omnipotent orthography oxidize parabola paradigm parameter

pecuniary photosynthesis plagiarize plasma polymer precipitous quasar quotidian recapitulate reciprocal reparation respiration sanguine soliloquy subjugate suffragist supercilious tautology taxonomy tectonic tempestuous thermodynamics totalitarian unctuous usurp vacuous vehement vortex winnow wrought xenophobe yeoman ziggurat

Houghton Mifflin Press Release

When's the last time you were happy to hear the phrases "some assembly required" or "your call is important to us?" And for that matter, what exactly is an economic adjustment, a broad abstraction or sound science?

According to Dr. Paul Wasserman, professor emeritus and founding dean of the College of Information Studies at the University of Maryland, these deceptive phrases are good examples of what can be called doublespeak, weasel words, or even gobbledygook.

Wasserman says we are bombarded with examples of doublespeak ranging from the politically correct to the downright annoying from corporations, the media and politicians.

He has parlayed his interest in gobbledygook into a new book co-authored with Don Hausrath, who also has ties to the university as a former adjunct faculty member at the College of Information Studies. Wasserman and Hausrath have translated over 1,200 examples of doublespeak in Weasel Words: The Dictionary of American Doublespeak,(Capital Books) scheduled for release in November (2005).

University of Maryland News
19 October 2005