Posts Tagged ‘research’

PBS NewsHour presents “Autism Now”

April 26, 2011

The PBS NewsHour just completed a 6-part series about autism. Causes, prevalence, research, funding: it’s all in there.

All six parts, as well as extended interviews with some of the experts are available on the NewsHour Web site, where you can also reserve a DVD of the series.

The impact of sleep on sustained attention

April 18, 2011

This weekend’s NY Times Magazine is all about health – everything from the toxicity of sugar to the question of whether cell phones cause cancer. One article that caught our eye (at least after a cup of morning coffee) asks “How little sleep can you get away with?

David Dinges, the head of the Sleep and Chronobiology Laboratory at the Hospital at the University of Pennsylvania has asked just this question, and the answer is: you should really try to get 8 hours. Dinges’ 2003 study assigned dozens of subjects to three different groups: some slept four hours, others six hours and others, for the lucky control group, eight hours — for two weeks in the lab. The study used a measure called psychomotor vigilance task, or PVT. PVT is a “tedious but simple if you’ve been sleeping well. It measures the sustained attention that is vital for pilots, truck drivers, astronauts. Attention is also key for focusing during long meetings; for reading a paragraph just once, instead of five times; for driving a car. It takes the equivalent of only a two-second lapse for a driver to veer into oncoming traffic.”

The results?

Those who had eight hours of sleep hardly had any attention lapses and no cognitive declines over the 14 days of the study. What was interesting was that those in the four- and six-hour groups had P.V.T. results that declined steadily with almost each passing day. Though the four-hour subjects performed far worse, the six-hour group also consistently fell off-task. By the sixth day, 25 percent of the six-hour group was falling asleep at the computer. And at the end of the study, they were lapsing fives times as much as they did the first day.

The six-hour subjects fared no better — steadily declining over the two weeks — on a test of working memory in which they had to remember numbers and symbols and substitute one for the other. The same was true for an addition-subtraction task that measures speed and accuracy. All told, by the end of two weeks, the six-hour sleepers were as impaired as those who, in another Dinges study, had been sleep-deprived for 24 hours straight — the cognitive equivalent of being legally drunk.

These results are particularly interesting in light of a study recently published in the journal SLEEP that indicated that loss of an hour of sleep per night among children with ADHD had a significant impact on their ability to remain focused and sustain attention From a Science Daily article summarizing the research: “The study suggests that even moderate reductions in sleep duration can affect neurobehavioral functioning, which may have a negative impact on the academic performance of children with ADHD.”

Results of multivariate analyses of variance show that after mean nightly sleep loss of about 55 minutes for six nights, the performance of children with ADHD on a neurobehavioral test deteriorated from the subclinical range to the clinical range of inattention on four of six measures, including omission errors (missed targets) and reaction time. Children with ADHD generally committed more omission errors than controls. Although the performance of children in the control group also deteriorated after mean nightly sleep loss of 34 minutes for six nights, it did not reach a clinical level of inattention on any of the six measures.

Reut Gruber, PhD, assistant professor in the department of psychiatry at McGill University and director of the Attention, Behavior and Sleep Laboratory at Douglas Mental Health University Institute in Montreal, Québec, quoted in the Science Daily article, has advice for parents:

“The reduction in sleep duration in our study was modest and similar to the sleep deprivation that might occur in daily life,” Gruber said. “Thus, even small changes in dinner time, computer time, or staying up to do homework could result in poorer neurobehavioral functioning the following day and affect sustained attention and vigilance, which are essential for optimal academic performance.”

“An important implication of the present study is that investments in programs that aim to decrease sleep deprivation may lead to improvements in neurobehavioral functioning and academic performance,” she said.

I don’t know about you, but we’re going to go take a nap.

The Thirsty Linguist reviews Oliver Sacks’ latest book “The Mind’s Eye”

March 31, 2011

Doctor and author Oliver Sacks is known for bringing neuroscience to the masses. In The Man Who Mistook His Wife for a Hat and Awakenings (which was made into a movie starring Robert DeNiro and Robin Williams), Sacks explores neurological disorders with the writing skills of a novelist.

Our friend, the Thirsty Linguist, reviews Sacks’ latest book, The Mind’s Eye, which explores the human experience of vision:

As in some of his previous books, Sacks presents case histories of individuals suffering from neurological injury or disease, and uses these histories as a means to probe the capacities of the mind. Lilian Kallir, for example, is a pianist who loses the ability to read, even though the rest of her vision remains intact and, puzzingly, she can still write. Sacks follows Lilian’s story over a period of three years, describing the coping strategies she develops, such as color-coding items in her home, as well as the new talents that arise unexpectedly with her condition, such as the ability to re-arrange musical pieces in her mind without consulting a score. Howard Engel, featured in another case history, is a writer who also loses the ability to read, but he approaches his situation differently: he rejects audiobooks, refuses to give up the world of text, and painstakingly learns his ABCs all over again.

Lilian’s and Howard’s cases both suggest that the brain has a specific location dedicated to reading. But it is not at all obvious why this should be so. Unlike spoken language, which evolved over hundreds of thousands of years, written language is a relatively recent cultural invention that offered no survival advantage to humans in primitive societies. Plasticity offers a potential answer to this conundrum: we can and do use structures in the brain for purposes very different from those for which they evolved. Sacks casts a wide net to gather evidence for this idea. He describes case histories of nineteenth century neurologists, who treated patients with symptoms similar to Lilian’s and Howard’s. He cites evolutionary thinkers from Charles Darwin and Alfred Russel Wallace to Stephen Jay Gould and Elisabeth Vrba, tracing the history of the notion of “exaptation,” a biological adaptation which gets put to a new use. He presents key results from imaging studies which demonstrate that different areas of the brain are active during reading versus listening. And he summarizes a computational study of over 100 writing systems which shows that, despite their diversity, these systems share basic visual signatures which resemble those found in natural settings.

The Mind’s Eye thus offers narrative science writing of the most satisfying kind. We delight in pedagogical moments because Sacks weaves them seamlessly into the case histories. We get drawn into the topics of evolution, brain imaging, and computation because we want to follow people like Lilian and Howard. “Make characters the matter of your narrative,” advises James Shreeve in A Field Guide for Science Writers, “and let the science spill from their relations.” Sacks does precisely that.

If Sacks’ work intrigues you, you might also be interested in:

It’s About Time…

March 29, 2011

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

Competing Memories

March 25, 2011

Does something like this ever happen to you?  From Yale psychologist Brice Kuhl, quoted in a NY Times article about memory:

“I park in a garage every day at work, and I park in a different space every day, depending on availability. And I very often walk to where I parked the day before. It’s not that I totally forgot where I parked, it’s just that I still remember yesterday’s spot.”

When the brain is cluttered with similar items (say a new password replacing an expired one, or a new phone number), we have difficulty recalling just one. Kuhl’s research (published in the Proceedings of the National Academy of Sciences) indicates that this difficulty is reflected in “more ambiguous” neural activation when engaged in competitive remembering as compared to “more robust” activation for non-competitive memories.

TED Talk: Dr. Michael Merzenich on Rewiring the Brain

March 23, 2011

Dr. Michael Merzenich is a pioneer in brain plasticity research. In this TED Talk, recorded in 2004, Dr. Merzenich describes impairments to the brain’s processing ability, and how we can train the brain back to normal processing:

We now have a large body of literature that demonstrates that the fundamental problem that occurs in the majority of children that have early language impairments, and that are going to struggle to learn to read, is that their language processor is created in a defective form. And the reason that it rises in a defective form is because early in the baby’s brain’s life the machine process is noisy. It’s that simple. It’s a signal to noise problem. Okay? And there are a lot of things that contribute to that. There are numerous inherited faults that could make the machine process noisier.

Every sound the child hears uncorrected is muffled. It’s degraded. The child’s native language is such a case is not English. It’s not Japanese. It’s muffled English. It’s degraded Japanese. It’s crap. And the brain specializes for it. It creates a representation of language crap. And then the child is stuck with it.

Now the crap doesn’t just happen in the ear. It can also happen in the brain. The brain itself can be noisy. It’s commonly noisy. There are many inherited faults that can make it noisier. And the native language for a child with such a brain is degraded. It’s not English. It’s noisy English. And that results in defective representations of sounds of words, not normal, a different strategy, by a machine that has different space constants. And you can look in the brain of such a child and record those time constants. They are about an order of magnitude longer, about 11 times longer in duration on average, than in a normal child. Space constants are about three times greater. Such a child will have memory and cognitive deficits in this domain. Of course they will. Because as a receiver of language, they are receiving it and representing it. And in information it’s representing crap. And they are going to have poor reading skills. Because reading is dependent upon the translation of word sounds into this orthographic or visual representational form. If you don’t have a brain representation of word sounds that translation makes no sense. And you are going to have corresponding abnormal neurology.

The point is is that you can train the brain out of this. A way to think about this is you can actually re-refine the processing capacity of the machinery by changing it. Changing it in detail. It takes about 30 hours on the average. And we’ve accomplished that in about 430,000 kids today. Actually about 15,000 children are being trained as we speak. And actually when you look at the impacts, the impacts are substantial.

Think of a classroom of children in the language arts. Think of the children on the slow side of the class. We have the potential to move most of those children to the middle or to the right side. In addition to accurate language training it also fixes memory and cognition speech fluency and speech production, And an important language dependent skill is enabled by this training — that is to say reading. And to a large extent it fixes the brain. You can look down in the brain of a child. in a variety of tasks that scientists have at Stanford, and MIT, and UCSF, and UCLA, and a number of other institutions. And children operating in various language behaviors, or in various reading behaviors, you see for the most extent, for most children, their neuronal responses, complexly abnormal before you start, are normalized by the training.

There’s some stuff about monkeys in the middle that went a little over our heads, but the talk is worth the 20 minute investment.

Brain Foods

March 10, 2011

Family Education Network breaks down the top brain foods, which can improve your mood, thinking, and mental skills.

Some aren’t surprising (and won’t come as very welcome news to children): broccoli is a great source of vitamin K, which enhances cognitive function. And pinach improves learning capacity and motor skills while slowing down age-related brain function.

But there are a few pleasant surprises for those who don’t get too excited about eating their vegetables:

  • Eggs contain choline, which boosts the memory center of the brain.
  • Yogurt improves alertness and contains tyrosin, an amino acid that produces dopamine (a neurotransmitter).
  • Walnuts contain vitamins E and B6, which are good for the nervous system, and fatty acids that help brain function.

And of course, the kicker: dark chocolate. It contains antioxidants and flavonoids that are great for the brain.

The full slide show is on the Family Education Network Web site. You might also be interested in these posts on our blog about brain-based eating:

Moonwalking with Einstein

February 28, 2011

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

February 17, 2011

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.

Blueberries on the brain

February 9, 2011

The January 2011 issue of Scientific American Mind picks up some research we have been following about flavonoids, which research shows may improve memory, learning and general cognitive function:

Emerging research suggests that compounds in blueberries known as flavonoids may improve memory, learning and general cognitive function, including reasoning skills, decision making, verbal comprehension and numerical ability. In addition, studies comparing dietary habits with cognitive function in adults hint that consuming flavonoids may help slow the decline in mental facility that is often seen with aging and might even provide protection against disorders such as Alzheimer’s and Parkinson’s.

We have previously posted about the impact of flavonoids (which also occur in chocolate) on math skills. In the article we cited, study authors indicated flavonoids worked by increasing blood flow to the brain. This more recent article indicates that researchers believe flavonoids impact cognition by interacting with proteins that are integral to brain-cell structure and function.

Either way, we like the idea of good-tasting foods being good for the brain!


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