New research on the neural system of language

Neuroscientists have long known that particular areas of the brain are responsible for the comprehension and production of language. But new research points to the criticality of pathways between these areas for various components of language.

From a Science Daily article summarizing the research:

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.

MRI image shows Brocca's (yellow) and Wernicke's (purple) regions, connected by critical neural pathways. (Image credit: Stephen Wilson, Science Daily)

University of Arizona Professor of Speech and Hearing Stephen Wilson was one of the lead researchers:

If you have damage to the lower pathway, you have damage to the lexicon and semantics. 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.

Professor Wilson collaborated on the research with colleagues from the University of California at San Francisco and the Scientific Institute and University Hospital San Raffaele in Milan, Italy. The research was published in the journal Neuron.

It’s About Time…

Auditory processing describes what happens when the brain recognizes and interprets sounds. Humans hear when energy that we recognize as sound travels through the ear and is changed into electrical information that can be interpreted by the brain. For many students, something is adversely affecting the processing or interpretation of this information. As a result, these students often do not recognize subtle differences between sounds in words, even though the sounds themselves are loud and clear. For example: “Tell me how a chair and a couch are alike” may sound to a child struggling with auditory processing like “Tell me how a hair and a cow are alike.”

These kinds of problems are more likely to occur when the child is in a noisy environment or is listening to complex information.

The Temporal Dynamics of Learning Center (TDLC) at the University of California is one of six Science of Learning Centers funded by the National Science Foundation. Its purpose is “to understand how the element of time and timing is critical for learning, and to apply this understanding to improve educational practice.”

What is the role of timing in learning? From the TDLC Web site:

When you learn new facts, interact with colleagues and teachers, experiment with new gadgets, or engage in countless other learning activities, timing plays a role in the functioning of your neurons, in the communication between and within sensory systems, and in the interactions between different regions of your brain. The success or failure of attempts to communicate using gestures, expressions and verbal language also depend on timing.

In short, timing is critical for learning at every level, from learning the precise temporal patterns of speech sounds, to learning appropriate sequences of movements, to optimal training and instructional schedules for learning, to interpreting the streams of social signals that reinforce learning in the classroom.

Learning depends on the fine-scale structure of the timing between stimuli, response, and reward. The brain is exquisitely sensitive to the temporal structure of sensory experience:

• at the millisecond time scale in the auditory system;
• at the second time scale in reinforcement learning;
• at the minute time scale for action-perception adaptation; and
• at the day-to-week time scale for consolidation and maturation.

Each level of learning has its own temporal dynamics, and its own timing constraints that affect learning. These levels are not independent, but instead, timing constraints at one level affect learning at another level in a nested way. For example, the dynamics at the cellular level, which is often on the order of milliseconds, implement learning on the whole-brain and behavioral level on much longer time scales, including memories that last a lifetime.

The past decade of neuroscience research demonstrates that the intrinsic temporal dynamics of processes within the brain also reinforce and constrain learning. For example, we have discovered that slow learners tend to have slow “shutter speeds” in terms of how their brains take in and process information. For some poor readers, the underlying problem is the their inability to perceive fast acoustic changes in speech sounds (phonemes) that must be accurately perceived in order to learn letter-sound correspondence rules for reading.

Fortunately, says the TDLC Web site, “Neuroscience-based training regimes that improve this temporal processing ability improve both spoken and written language learning in struggling readers.”

One such training program is the Fast ForWord program, which can be an effective intervention for children with struggling with processing rates because it goes right to the cause of the problem, strengthening the gray matter in the area of the brain responsible for processing auditory information. With Fast ForWord, children are first exposed to sounds that are modified to enhance the minute acoustic differences between similar speech sounds. As children demonstrate proficiency and build new neural pathways, the program automatically reduces the level of modification, until eventually students are challenged to process normal speech sounds.

When their brains are processing speech sounds at peak efficiency, students can better  recognize and discriminate the rapidly changing sounds that are important for discriminating phonemes (the smallest units of speech that distinguish one word from another). As a result, they will more easily:

• Attend and respond to directions and class discussions
• Remember questions, directions, and information
• Learn to read and become a better reader

Creativity in Young Learners

Two blogs we follow have recently tackled the topic of creativity in young learners, each from a slightly different perspective:

A recent post at Sharpbrains.com features an excerpt from John Medina’s book Brain Rules for Baby that looks at the link between creativity and a certain kind of risk-taking. Medina describes “functional impulsivity”, the presence of which makes you more creative:

What ever their gender, creative entrepreneurs have functional impulsivity instincts in spades. They score atmospherically high on tests that measure risk­ taking, and they have a strong ability to cope with ambiguity. When their brains are caught in the act of being creative, the medial and orbital sectors of the pre­frontal cortex, regions just behind the eyes, light up like crazy on an fMRI. More “managerial types” (that’s actually what researchers call them) don’t have these scores—or these neural activities.

Medina is careful to differentiate functional impulsivity from, say, putting life and limb at risk on a dare, which tends to be associated not with creativity but with substance abuse.

At Scientific Learning’s Science of Learning blog, the topic of creativity is focused on the books of Edward de Bono, who proposes methods for teaching students to think creatively and “create context from nothingness.”

In one example, he describes how a teacher shows his students a photo of people dressed in street clothes wading through water at a beach. The teacher then asks the students to come up with interpretations as to what is going on in the picture. The teacher has de-emphasized the context; the crux of the activity is to develop the context using their imaginations.

In this situation, de Bono says that students might respond by saying that the picture shows a group of people caught by the tide, or a group crossing a flooded river, or people wading out to a ferry boat which cannot come to shore, or people coming ashore from a wrecked boat.

The fact that the photo is actually of a group of people protesting at a beach is completely irrelevant. The author stresses that the right answer is not important; generating as many interpretations as possible is. The teacher has created a safe, controlled environment and activity where students are encouraged to think outside the box and exercise creative habits of mind, free from qualitative judgment. He even goes on to suggest that if a student comes up with a particularly unfeasible interpretation, the teacher should not judge, but continue to question the student until the context for the interpretation becomes clear, encouraging cultivation of the student’s creative skill.

Medina’s books on the neuroscience of development differentiate between the “seeds”, which is what a child is born with, and the “soil” which is what parents and others can do to nurture that raw material. These two posts, taken together, indicate that when it comes to creativity, both play a role.

Moonwalking with Einstein

Last weekend’s NY Times Magazine featured an excerpt from journalist Joshua Foer’s new book Moonwalking with Einstein: The Art and Science of Remembering Everything. It’s the fascinating story of his quest to become the memory champion of the United States (add that to the list of things we didn’t know anything about).

As we’ve previously posted, there’s an important distinction between memory and memorization. Nonetheless, memorization techniques can give us clues about memory, particularly from an evolutionary standpoint. For example, Foer highlights a study that showed that expert memorizers have neither anatomically distinguishable brains nor above average levels of cognitive abilities. But what they do share is a higher level of activation in the area of the brain responsible for visual and spatial memory. Experts attribute this to the fact that our ancestors relied on visual spatial memory for survival (where’s the food? where are the predators?).

Foer’s journey to the title is interesting, at least in part because he really set out just to learn about memorization and ended up a champion. The Times article links to two resources for memorizing numbers and names. For more on Foer, check out this story by NPR’s All Things Considered.

TED Talk on the Linguistic Genius of Babies

In this great 10-minute lecture, Patricia Kuhl, co-director of the Institute for Brain and Learning Sciences at the University of Washington, shares her findings about how babies learn one language over another — by listening to the humans around them and “taking statistics” on the sounds they need to know.

Experiments and brain imaging show how 6-month-old babies use sophisticated reasoning to understand their world. Dr. Kuhl’s work has played a major role in demonstrating how early exposure to language alters the brain. It has implications for critical periods in development, for bilingual education and reading readiness, for developmental disabilities involving language, and for research on computer understanding of speech.

Synaptic Exuberance!

Babies are born with all the brain cells they need. But it’s the connections between these cells that are important. During a period of what scientists call “synaptic exuberance”, babies literally develop as many as ten to twenty thousand connections per second.

Robert Krulwich, host of NPR’s so-called “Sciency Blog“, examines synaptic exuberance, as demonstrated by 9-month old Charles-Edward Vachon in a creative time-capture video:

More interesting, perhaps, than this rapid development of neural connections early in life is that, as Krulwich says, we overdo it. As we approach our teenage years, our brains start to prune these connections, focusing on quality over quantity based on our early life experiences. The brain, Krulwich quotes Dr. Harry Chugani, “allows for a fine-tuning of neuronal circuits, based on early exposure and environmental nurturing, that makes the neuronal architecture of each person unique.”

Chugani, Chief of the division of Pediatric Neurology at Children’s Hospital of Michigan and professor of pediatrics, neurology, and radiology at Wayne State University in Detroit, has extensively studied the developing brain. His article, Fine Tuning the Baby Brain, which appears on the Dana Foundation Web site, digs deeper into questions of why the baby brain consumes twice as much energy as an adult brain, and how the brain continues to remodel itself throughout life. Definitely worth a read.

The effect of mood on insight

We’re suckers for a scientific study that involves watching a Robin Williams standup routine…

Consider the task of listening to a conversation in a noisy room or concentrating on a particularly challenging puzzle. Research shows that these tasks are typically associated with activation of the anterior cingulate cortex in the brain. Cells in this area are active when we narrow our attention to concentrate on a difficult task.

But what about insight – that ability to quickly “see” the solution to a puzzle or problem (think “AHA!”), rather than solve it by brute force? Insight requires a widening of associations, rather than a narrowing. For insight to occur, the brain must be open to looser associations and connections. We must, as the scientists would say, be in a “diffuse attentional state.”

So how do we get there? The New York Times summarizes research that indicates mood is a significant factor, and that humor (here’s where the Robin Williams part comes in) is important:

In a just completed study, researchers at Northwestern University found that people were more likely to solve word puzzles with sudden insight when they were amused, having just seen a short comedy routine.

“What we think is happening,” said Mark Beeman, a neuroscientist who conducted the study with Karuna Subramaniam, a graduate student, “is that the humor, this positive mood, is lowering the brain’s threshold for detecting weaker or more remote connections” to solve puzzles.

So next time you’re stuck on a problem, should you just remember the funny joke you heard last week?

The findings fit with dozens of experiments linking positive moods to better creative problem-solving. “The implication is that positive mood engages this broad, diffuse attentional state that is both perceptual and visual,” said Dr. Anderson. “You’re not only thinking more broadly, you’re literally seeing more. The two systems are working in parallel.”

The Times Web site has a pretty cool interactive experiment that you can use to test the effect of mood on your own insight. Check it out here.

The Beautiful Mind

From the NY Times:

It is only fitting that the story of the brain should be a visual one, for the visuals had the ancients fooled for millenniums. The brain was so ugly that they assumed the mind must lie elsewhere. Now those same skeletal silhouettes glow plump and brightly colored, courtesy of a variety of inserted genes encoding fluorescent molecules. A glossy new art book, Portraits of the Mind: Visualizing the Brain from Antiquity to the 21st Century, hopes to draw the general reader into neuroscience with the sheer beauty of its images.

The Times has a great review of the book. And check out these fantastic photo excerpts.

 

 

Your Brain on Metaphors

We’re suckers for an article tagged “philosophy” and “neuroscience.”

In the NY Times, Robert Sapolsky explores the fact that while the neuron of a common housefly is remarkably similar to that of a human, we benefit from having a lot more neurons (about 100 million for every one the fly has). And, as Sapolsky says, this quantity yields quality, enabling us to carry out complex tasks like the digit manipulation required to trill on a piano, or make the decision to study hard to get good grades and eventually a good job. Gophers, Sapolsky points out, don’t do that.

Sapolsky, though, is taken with a different human-only trait:

Symbols, metaphors, analogies, parables, synecdoche, figures of speech: we understand them. We understand that a captain wants more than just hands when he orders all of them on deck. We understand that Kafka’s “Metamorphosis” isn’t really about a cockroach. If we are of a certain theological ilk, we see bread and wine intertwined with body and blood. We grasp that the right piece of cloth can represent a nation and its values, and that setting fire to such a flag is a highly charged act. We can learn that a certain combination of sounds put together by Tchaikovsky represents Napoleon getting his butt kicked just outside Moscow. And that the name “Napoleon,” in this case, represents thousands and thousands of soldiers dying cold and hungry, far from home.

And we even understand that June isn’t literally busting out all over. It would seem that doing this would be hard enough to cause a brainstorm. So where did this facility with symbolism come from? It strikes me that the human brain has evolved a necessary shortcut for doing so, and with some major implications.

We won’t get into the neurochemical analysis that Sapolsky does, but if you’re a fan of the brain, his article is a great read.

 

Music on the brain

The relationship between music and language (and to a degree, overall academic performance) has been explored extensively in the research. We’ve previously posted on the topic (and have also posted on why it’s so hard to shake a song that’s stuck in your head, which isn’t really as academically important, but is interesting…).

Most parents are familiar with the so-called Mozart Effect, wherein exposure to music (or more specifically, classical music) (or even more specifically music written by Mozart) (or if  you really want to get down to brass tacks, the first movement “allegro con spirito” of the Mozart Sonata KV 448 for Two Pianos in D Major) can improve academic performance. The idea was born out of a 1993 study published in Nature that reported that individuals who listened to the Mozart Sonata scored significantly higher on standard ized tests of abstract/spatial reasoning ability than those who were instructed to relax or those who just sat there in silence.

Listening to music we like does make us feel good, which, in turn, increases focus and attention, which improves performance on many tests of mental sharpness. According to an article in the Racine Journal Times, some studies have shown “improvement in the kind of mental skills we use in doing complex math problems, interpreting driving directions and pondering how to fit a large bookcase in the trunk of a small car.”

But the idea that simply listening to music will have a profound and lasting effect on academic performance has generally been dismissed. (For a thorough analysis of the shortcomings of the initial research, check out this post at the Sharp Brains blog). Instead, researchers (including, says the Journal Times, those who conducted the original “Mozart Effect” study) have shifted to focus on the cognitive effect of learning to make music. Says the Journal Times: “If you want music to sharpen your senses, boost your ability to focus and perhaps even improve your memory, the latest word from science is you’ll need more than hype and a loaded iPod. You gotta get in there and play. Or sing, bang or pluck.”

Learning to make music engages and demands coordination among many brain regions, including those that process sights, sounds, emotions and memories, says Dr. Gottfried Schlaug, a Harvard University neurologist.

Years ago, Schlaug found a glaring and suggestive difference between the brains of 30 professional musicians and 30 non-musician adults of matched age and gender.

In the musicians, the bundle of connective fibers that carry messages between the brain’s right and left hemispheres – a structure called the corpus callosum – was larger and denser on average than that of their non-musical peers. The brawnier bridge was particularly notable toward the rear of the brain, at the crossing that links areas responsible for sensory perception and voluntary movement.

It suggested not only that musicians might be able to more nimbly react to incoming information but also that their brains might be more resilient and adaptable, allowing right and left hemispheres, which specialize in separate functions, to work better together.

Schlaug and colleagues also found that the musicians who had begun their musical training before the age of 7 showed the most pronounced differences – suggesting an early start might rewire the brain most dramatically.

Over at the New Science of Learning Blog, Dr. William Jenkins (one of the neuroscientists behind the Fast ForWord programs), highlights a recent article, Music Training for the Development of Auditory Skills by Nina Kraus and Bharath Chandrasekaran, that examines three specific areas of brain function where music training positively affects function:

• Transfer of cognitive skills: Music has been shown to affect how the brain processes pitch, timing and timbre. Along with describing music, these are also key elements of speech and language—that are positively affected by musical training.
• Fine tuning of auditory skills: “Musicians, compared with non-musicians, more effectively represent the most meaningful, information-bearing elements in sounds — for example, the segment of a baby’s cry that signals emotional meaning, the upper note of a musical chord or the portion of the Mandarin Chinese pitch contour that corresponds to a note along the diatonic musical scale.” While music does not appear to affect visual memory or attention, research shows that it does affect auditory verbal memory and auditory attention.
• Better recognition of “regularities”: The human brain is wired to filter regular predictable patterns out from the noise surrounding us (e.g., we can pick out a friend’s voice in a room filled with many other sounds and voices.) Musical training enhances this cognitive ability.

Based on this information, Kraus and Chandresekaran argue “that active engagement with music promotes an adaptive auditory system that is crucial for the development of listening skills. An adaptive auditory system that continuously regulates its activity based on contextual demands is crucial for processing information during everyday listening tasks.”

So while the idea of a Mozart Effect, by which we can improve academic performance simply by exposing children to music, seems feeble at best, there are significant cognitive benefits to musical training, particularly in the area of language and processing abilities.