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Archive for the ‘Cognition’ Category

Talking with Your Hands

By Dr. Richard G. Petty, M.D. | November 16th, 2007

In recent years there has been a small but growing literature that seems to support an idea going back to Roman times: certain specific movements may facilitate learning and a number of positive mental states.

Now, according to research from the University of Chicago that is reported in this month’s issue of Journal of Experimental Psychology: General gesturing can help children to learn new and correct mathematical problem-solving strategies. And the learning sticks: if they are taught new material later, children taught to gesture are more likely to succeed on math problems.

The investigators conducted two studies of 176 children in late third and early fourth grade, all of whom had been making mistakes in solving math problems. The children were randomly assigned the students to three groups:

  1. Told to gesture
  2. Told not to gesture
  3. Not told to do either

In the studies’ baseline phase, students had to solve six age appropriate math problems on a chalkboard and explain to an experimenter how they solved each one. The researchers coded the children’s videotaped efforts, analyzing gestures and utterances that conveyed problem-solving strategies.

Compared with the children who were not told to do anything, those who were told to move their hands when explaining how they had solved a problem were four times as likely to manually express correct new ways to solve problems. They still did not give the right answer, but their gestures revealed an implicit knowledge of mathematical ideas. As one example, if the problem needed for the sides to be equal, children might sweep their palm first under a problem’s left side and then under its right side. So they had implicit knowledge. Their problem was in turning explicit knowledge into correct answers. The second study showed that gesturing prepared them to benefit from subsequent instruction. Children told to gesture solved 1.5 times more problems correctly compared with the children who had been told not to gesture.

The authors conclude,

“Telling children to gesture encourages them to convey previously unexpressed, implicit ideas, which in turn makes them receptive to instruction that leads to learning.”

Gesturing appears to help children to produce new problem-solving strategies, which in turn gets them ready to learn. The authors speculate that gesturing may help kids notice aspects of the math problems that may be more easily grasped through gestural representation

The findings extend previous research that body movement not only helps people to express things they may not be able to verbally articulate, but actually to think better. At the same time, gesturing offers a potentially powerful new way to augment the teaching of math. Strategies for math problems have focused on externalizing working memory, such as writing things down in certain ways. However, children often find it hard to recall and use those strategies. Gesturing may be more accessible, and help break through the roadblock.

This makes sense: we are hardwired to learn motor actions. That was an important skill long before the first person learned the basics of arithmetic. It is quite well known in educational circles that when it comes to learning, “doing” is 2-3 times more efficient than “listening.” But even “doing” is nowhere near as good as questioning, being questioned and then teaching.

(The entire article is available for free download here.)

“He who wishes to teach us a truth should not tell it to us, but simply suggest it with a brief gesture, a gesture which starts an ideal trajectory in the air along which we glide until we find ourselves at the feet of the new.”
–José Ortega y Gasset (Spanish Philosopher, 1883-1956)

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Nutrition, Learning and Memory

By Dr. Richard G. Petty, M.D. | October 9th, 2007

We have talked about the burgeoning data linking food with mood, behavior and cognition.

I have just seen a new study that really adds to our knowledge and contributes information that we can all use.

Scientists in Europe, Australia and Indonesia have published data in the American Journal of Clinical Nutrition suggesting that nutrition can improve verbal learning and memory in schoolchildren.

This study was undertaken by the NEMO study group (Nutrition Enhancement for Mental Optimization) that consists of the Unilever Food and Health Research Institute (Vlaardingen, The Netherlands); CSIRO, Human Nutrition (Adelaide, Australia) and the SEAMEO-TROPMED Regional Center for Community Nutrition, University of Indonesia (Jakarta Pusat, Indonesia).

It was a 12-month study of 780 children in Australia and Indonesia in which the researchers evaluated the effects of adding a specific vitamin and mineral mixture to a daily drink.

The study population consisted of 396 well-nourished children in Australia and 384 poorly nourished children in Indonesia. In each country, the children were randomly allocated to one of four groups, receiving a drink with either:

  1. A mixture of micronutrients (iron, zinc, folate and vitamins A, B-6, B-12 and C)
  2. Fish oil (DHA and EPA)
  3. Both the micronutrient mixture and the fish oil
  4. Nothing added, i.e. placebo


In Australia, children who received the daily drink with the added vitamin and mineral mixture performed significantly better on tests of mental performance tests than children in a control group who received the drink but without added nutrients. In Indonesia a similar trend was observed, but this time only in the girls.

After twelve months, children in Australia who received the drink with the nutrient mix showed higher blood levels of these micronutrients, which means that their bodies were taking up the nutrients. In addition, they performed significantly better on tests measuring their learning and memory capabilities compared to children in the other groups. A similar trend was observed in Indonesia, but only in the girls. The addition of fish oil to the fortified drink did not conclusively show any additional effects on cognition.

This study adds to the mounting evidence that nutrition plays an important role in cognitive development in children, even in children who are enjoying a “normal” diet. Deficiencies in iron and iodine have been linked to impaired cognitive development in young children for over a century and there is now emerging evidence that deficiencies in zinc, folate and vitamin B12 may each compromise mental development in children. More recently, fish oils (EPA, DHA) have also been linked to child cognitive development.

Most previous studies have focused on deficiencies in single nutrients in young age groups, despite the well-known observation that the brain continues to grow and develop during childhood, adolescence and early adulthood. Little is known about the role of nutrition on mental development after the age of 2. In addition very other few studies have looked at the effect of offering a mix of nutrients. Until this study, there were very few randomized controlled intervention studies assessing the impact of a multiple-micronutrient intervention on cognitive function in schoolchildren.

The investigators recommend further research to investigate the exact role of DHA and EPA in healthy school-aged children. Another research focus is the further optimization of cognitive development tests with respect to their validity and sensitivity across cultures. The scientists suggest that the smaller effects of the vitamins and minerals in Indonesia could be a result of a lower sensitivity of the cognitive tests in that country.

This research raises many interesting points:

  • Is it possible that the healthy Australian diet is actually nothing of the sort?
  • Is it possible that if the diet is adequate, that “super-nutrition” can help a child to exceed his or her potential?
  • Are there key ages when nutrition can help, or is the effect maintained across the age range?
  • Does nutritional supplementation have a long-term impact on a child?
  • Have we even found the optimal mixture for child cognitive development? Might higher amounts of any nutrients – particularly fish oils – produce better effects, or might they be toxic, as we saw in the case of vitamin A supplementation?
  • Are we using the correct cognitive development tests to pick up changes in different cultures? As an example, could the smaller effects of the vitamins and minerals in Indonesia be a result of a lower sensitivity of the cognitive tests in that country? Or is it that the children are also missing out on some other trace nutrients?


Many questions, but the take home message is this: careful nutritional supplementation may have considerable benefits to a child, even one growing up in an affluent culture.

“Learning is a weightless treasure you always carry easily.”
–Chinese Proverb

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Protecting Yourself Against Alzheimer’s Disease

By Dr. Richard G. Petty, M.D. | October 1st, 2007

I have a keen interest in healthy aging, and we have talked before about some of the strategies that can help protect you against developing cognitive decline.

New research now shows for the first time that, of all lifelong activities, only a high level of mental or cognitive activity protects against the devastating memory loss of Alzheimer’s disease. High levels of social or physical activity are not enough.

Researchers from the Byrd Alzheimer’s Institute bred mice that are genetically predisposed to developing the pathological changes of Alzheimer’s diseases in their brains.

They then kept the mice in one of four housing environments — high social activity, high physical activity, high cognitive activity, or a single housing control environment and watched them from young adulthood through old age.

When the researchers tested the mice in a battery of memory tasks in old age, only the mice given a lifelong high level of cognitive activity were protected against memory impairment. In fact, these “high cognitive activity” mice performed as well as normal mice that do not develop Alzheimer’s disease. However the Alzheimer’s mice raised in one of the other three environments performed poorly in multiple memory tasks.

Not only was memory protected in Alzheimer’s mice by a high level of cognitive activity, but also brain levels of the abnormal protein beta-amyloid were substantially reduced. This protein, thought to be key for Alzheimer’s development, remained at soaring levels in the brains of Alzheimer’s mice raised in social or physical activity environments. Moreover, the researchers found that only the Alzheimer’s mice raised with high cognitive activity had an increase in connections between brain cells. Alzheimer’s mice raised in one of the other three housing environments had much fewer connections between their brain cells.

The new study is published in the Neurobiology of Learning and Memory Journal.

The lead researcher is Gary Arendash, and he had this to say:

“Our results call into question the earlier human studies suggesting social or physical activity provides protection against Alzheimer’s. Alzheimer’s begins in the brain several decades before any symptoms´ show up. That means adults in their forties and fifties need to make lifestyle choices now to decrease their risk of getting Alzheimer’s disease later.”


This is all correct, but there is still an important question: can we really extrapolate from mice to humans? Mice are social creatures, but not to the same extent as humans beings. The lion’s share of the human brain is dedicated to social activities, so you would expect that social activities will be particularly important in the maintenance of the human brain.

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Rhythms in the Brain

By Dr. Richard G. Petty, M.D. | July 28th, 2007

It is often a bit frustrating to read articles about the brain in which the writer says things like: “research has shown that the insula does this…” or “the amygdala does that…”

This idea that it is possible to reduce brain functions to regions of the brain is not correct. Some years ago I used the term “Neo-phrenology,” to describe this fallacy, though I am sure that I was not the first. (Phrenology was the old and discredited theory that you tell things about people by examining the bumps on their heads.)

So why is it a fallacy? The idea that certain functions can be “localized” to a bit of the brain is called “naïve localizationism.” The vast majority of the psychological functions of the brain are performed by distributed networks, not a single lump of tissue. One of the remarkable things about the human brain is that it can recruit new circuits as they are need. If we do not have enough brainpower to solve a problem, other systems are taken off line so that they do not distract and may be able to help. You have probably had the experience of working on something so intensely that you lose track of time, and fail to hear things going on around you.

Yes, there are regions that have jobs to do. For instance the auditory cortex is responsible for processing sound. But after that initial processing the rest of the brain becomes involved in deciding what to do with the information. The key to understanding the brain is how different regions of the brain communicate. As I recently mentioned in a different context, there are good reasons for believing that a number of problems, from the schizophrenias to the attention deficit disorders, may all be a result of poor communication between different regions of the brain.

Part of the problem is working out how regions communicate has been technical: we have not had the computers or hardware to do the measurements. But that is beginning to change.

Earl Miller, a professor of neuroscience at Massachusetts Institute of Technology’s Picower Institute for Learning and Memory, recently said that today’s faster computers and more advanced electronics might provide scientists with the tools they need to unlock the brain’s mysteries.

“Multiple electrode recording techniques, offer a whole new level of brain interactions that can’t be seen using the [current] piecemeal approach.”

Two studies published recently in th journal Science support this idea.

In the first Thilo Womelsdorf and a group of neuroscientists at the F. C. Donders Center for Cognitive Neuroimaging at Radboud University Nijmegen in the Netherlands, looked at the electrical activities of groups of neurons in the brains of cats and monkeys wile they were engaged in an array of different tasks. They found that two groups of neurons could only communicate efficiently with each other when their rhythms are coordinated, or synchronized. If the rhythms are not coordinated, then one group sends information while the other is not ready to take it on and vice versa.

The researchers found that when the rhythms of electrical activity are synchronized between neurons in distinct brain areas, memories are made and tasks are completed more efficiently.

The other study, by scientists at the University of Melbourne in Australia, also revealed communication between the cerebral cortex and the deep medial temporal region.

They flashed two images at a group of macaque monkeys for less than a second. The monkeys had to decide whether the spatial orientation of a stack of bars in two images were the same or different. While the animals worked, researchers monitored the electrical fields in the posterior parietal cortex, which is one part of the system involved in directing spatial attention. At the same time they looked at the medial temporal area, a region deep in the midbrain that handles movement perception. The researchers had hypothesized that these two areas need to communicate with one another to enable reasoning.

The researchers observed activity first in the parietal cortex, followed by synchronous action there and in the medial temporal area. The delay illustrates “a top-down” feedback from the cortex, which then signals the lower area.

One of the authors, Trichur Vidyasagar, said,

“The parietal neurons seem to code for what is salient or relevant in the world and allocate attentional resources accordingly. The medial temporal neurons are sensory ones that process the visual signals, but due to the influence of the parietal cortex the activity across the medial temporal area is varied.”


The studies were accompanied by an editorial in which Robert Knight, a cognitive neuroscientist at the University of California, Berkeley, praised the findings - and their potential significance.

This research is important for two reasons:
First it confirms that the key to understanding the brain is the interaction of networks.

Second, there are a number of periodic disorders, such as depression, seasonal affective disorder, mania and even some rare types of episodic psychosis that are episodic and are not associated with any clearly defined neuroanatomical disruption. It may well be that some of the periodic symptoms are caused by intermittent network dysfunction, as a result of disturbed oscillatory dynamics.

“In all things there is a law of cycles.”
–Publius Cornelius Tacitus (Roman Historian, Writer, Orator and Public Official, A.D.56-c.120)

“Human beings, vegetables or cosmic dust, we all dance to the same mysterious tune, intoned in the distance by an invisible player.”
–Albert Einstein (German-born American Physicist and, in 1921, Winner of the Nobel Prize in Physics, 1879-1955)

“It has been said that a complete understanding of the Law of Cycles would bring man to a high degree of initiation. This Law of Periodicity underlies all the processes of nature and its study would lead a man out of the world of objective effects into that of subjective causes.”
–Alice A. Bailey (English Writer, Spiritual Teacher and Founder of the Arcane School, 1880-1949)

“At the heart of each of us, whatever our imperfections, there exists a silent pulse of perfect rhythm, a complex of wave forms and resonances, which is absolutely individual and unique, and yet connects us to everything in the universe. The act of getting in touch with this pulse can transform our personal experience and in some way alter the world around us.”
–George Leonard (American Aikidoist and Writer, 1923-)

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Sleep Deprivation

By Dr. Richard G. Petty, M.D. | June 16th, 2007

When I was a young doctor we used to work absurdly long hours: for more than three years I worked every other night and every other weekend. It was not uncommon to be on your feet for three at a time. It is a wonder that we didn’t die or make more mistakes.

We know that sleep deprivation is not healthy, but we are only now beginning to find out just how damaging it can be. One of the biggest problems is that sleep deprivation interferes with the normal functioning of the immune system.

I saw an interesting paper (NR619) at the 2007 Annual Meeting of the American Psychiatric Association in San Diego last month.

A team from Korea took sixteen healthy volunteers and made them stay awake for 48 hours. They found that even this relatively short period of sleep deprivation produced some impressive effects on the body and the mind:

  • Thyroid hormone levels rose
  • The speed and accuracy of reaction times fell
  • Blood glucose and protein levels rose, and there were disturbances in several liver function tests
  • White blood counts increased
  • There was a slight fall in immunoglobulin levels


We already know that insufficient sleep is associated with insulin resistance and weight gain, and it is likely that these are mediated by a rise in inflammatory mediators in the blood.

It is remarkable how quickly the effects occur.

And how pleased I am that young doctors no longer have to tolerate those incredibly long shifts.

Some things have changed for the better!

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