Archive for February, 2011

Consciousness and the Grandmother Cell

February 27, 2011

The notion of a grandmother cell is that there are specific neurons that represent a specific concept of object, such as your grandmother. Initially this concept was not generally accepted. The primary criticism was that too many cells would be needed to identify each individual face because each orientation, expression, and lighting on the face would be different. Moreover, the appearance of the face would change over time.

However, recent research summarized in a Scientific American Mind article1, not only resurrects the notion of the grandmother cell, but also relates it to the phenomenon of consciousness. This research involves placing electrodes in the brain to measure electrical activity. This procedure is so invasive that it is only justified for medical diagnosis and treatment. Neurons in the medial temporal lobe are the source of many epileptic seizures. This region includes the hippocampus and turns visual and other sensory percepts into memories. Although most neurons respond to categories of objects, a few of the neurons were much more discriminating. One hippocampal neuron responded only to photos of Jennifer Aniston, and not to pictures of other actresses. Moreover, the cell responded to seven different pictures of Jennifer Aniston. They also found cells that responded to images of Mother Theresa, to cute little animals, and to the Pythagorean theorem.

Further research, by a highly creative and painstaking research team, developed a technique for making concepts visible. They took a volunteer patient and recorded from a neuron that responded to images of the actor Josh Brolin (who was in her favorite movie) and to another neuron that fired in response to the scene of Marilyn Monroe standing on a subway grill. The patient looked at a monitor where these two images were superimposed. The activity of the two cells controlled the extent to which she saw Brolin or Monroe in the hybrid image. When the patient focused her thoughts on Brolin, the neuron associated with Brolin fired more strongly. Similarly when the patient focused her thoughts on Monroe, the neuron associated with Monroe fired more strongly. Feedback was arranged such that the more one cell fired relative to the other, the more visible that image became as the competing image faded. The image on the screen kept changing until only Brolin or only Monroe remained on the screen. The patient loved it and felt that she was controlling what she saw, which she was.

We know that we can control what we are thinking about and that corresponding neurons and neural circuits respond. But this is, as far as I know, the first demonstration of this phenomenon. By using and controlling the appropriate memory circuits we are able to build and maintain our minds.

1Koch, C. (2011). Being John Malkovich. Scientific American Mind, March/April, 18-19. 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Is Daydreaming Bad for You?

February 23, 2011

Your answer to this might be “yes” should you have heard some estimates that we use only 10% of our brains (See Healthymemory Blog Post, “How Much of Our Brain Do We Really Use”). If you have read that post  you should know that our brains our chugging away 24 hours a day, even when we are sleeping. Daydreaming has connotations of wasting time. A recent article1 puts the benefits and risks of daydreaming in perspective. Estimates are that, on average, we spend about 30% of our waking day daydreaming. Moreover, a neural network for daydreaming has been identified. It consists of three main regions: the medial prefrontal cortex, the posterior cingulate cortex, and the parietal cortex. The medial prefrontal cortex helps us imagine both ourselves and the thoughts and feelings of others. The posterior cingulate cortex brings up our personal memories. The parietal cortex has connections to the hippocampus, that key memory structure that is responsible for our personal episodic memories (our personal histories). This network is key to our sense of self.

Daydreaming can be bad. Indeed uncontrolled daydreaming can become pathological and require clinical interventions. On the other hand, daydreaming can be quite beneficial. Letting our minds run freely can be enjoyable and enlightening. When you can’t solve a problem, letting your mind run freely can sometimes stumble upon a solution. Even if it doesn’t lead to a solution, it can relax and refresh your mind. Daydreaming can also foster creativity. Creative people are sometimes characterized as dreamers. It has been noted that people who regularly catch themselves daydreaming and who notice when they’re doing it, seem to be most creative. Daydreaming can also be beneficial when you are bored or are in an uncomfortable situation, as it provides a means of escape.

Daydreaming can also be harmful when you dwell on unpleasant thoughts. Although it is good to learn from negative experiences, leave it at that (See the Healthymemory Blog Post, “Buddha’s Brain”). Like most activities, daydreaming is best done in moderation. Meditation is the exact opposite of daydreaming. In most types of meditation you focus your attention on a concept or process (see the Healthymemory Blog Posts “Costly Gadgets or Software Are Not Required for Healthy Memory,” “Continuing to Be Positive After Thanksgiving,” “Intensive Meditation Training Increases the Ability to Sustain Attention,” and “The Relaxation Response.”

Just as with your body, your mind needs a healthy balance of activities.

1Glausiusz, J. (2011). Living in a Dream World. Scientific American Mind, March/April, 24-31. 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Learning on the Web (and Elsewhere as Well)

February 20, 2011

Most surfing done on the web is superficial. Consequently, little learning takes place.1 Readers of the Healthymemory Blog will already know that effective learning requires the spending of attention. Most of the time people scan text on websites instead of reading it closely. This is the appropriate technique if someone is just trying to find something of interest or relevance. However, if someone just scans the web, little learning will take place. Moreover, bad habits can be developed if someone is constantly enticed by “hot” topics or keeps moving from one url to another without slowing down to think about and process something of interest.

Nielsen (see the first footnote) reports the results of a paper by Karpicke and Blunt that was published in Science. They measured the amount of information people could remember a week after reading a scientific text. So these people were not reading online, rather they were reading a conventional text book. The experiment involved two groups of students. One group simply read the text. The other group completed an elaborate test after reading the text. The students who had completed the elaborate test after reading remembered 145% more content after a week than students who simply read the text and did not do anything else. It is interesting to note that the people who took the test actually thought that they had learned 15% less than people who had read the text but did not take the test. The reason the test-takers thought they had learned less was that the test-taking exposed the gaps in their knowledge, though undermining their confidence, whereas the group that had not taken the test remained ignorant of their ignorance.

The test-taking condition employed here was a retrieval practice test. This involves

  1.  Reading the Text
  2. Recalling as much of the information as they could on a free-recall test.
  3. Reading the text again.
  4. Completing another free-recall test.

There was another group that simply read the text four times. Although these people remembered more than the people who read the text only once, the recall of the group doing the retrieval practice test was 64% better than the group that just read the text four times. So replacing 2 rereads with 2 tests substantially boosted people’s week-later performance. It is reasonable to think that the retrieval practice group in step 3 was aware of any information they had missed during their recall efforts in step 2. The reread only group remained ignorant of these gaps in their knowledge.

Of course, much more effort is involved in the retrieval practice test. One is constantly confronted with the problem of how much attention should be paid to an item of information. Does it need to be stored in memory so that in can be easily recalled, that is, accessible in personal memory. Or does one only need to take note of it and make a note, bookmark, or tag it. This is what the Healthymemory Blog terms accessible transactive memory. This is information that you cannot recall, but can easily find. Oftentimes, we know that the information is someplace, but cannot remember where. In this case, we say it is in available transactive memory, in that we know it is there, but cannot readily access it, In these cases we need to look for it or search for it.

It should be noted that it can be advantageous to take a test on a topic before you read or study the material. Previous Healthymemory Blog Posts on the work by Roediger demonstrate provide evidence for the benefits of this practice (“To Get It Right, Get It Wrong First”, and “The Benefits of Testing”).

1Nielsen, J. (2011). Test-Taking Enhances Learning. Http://www,useit.com/alertbox/learning-recall.html 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Jeopardy, Watson, and Transactive Memory

February 17, 2011

The recent competition between expert human contestants and the IBM computer, Watson, raises some interesting questions. These questions relate to transactive memory. Transactive memory refers to information that is not stored in one’s personal memory, but resides in another human’s memory or in some technological artifact, such as the internet or a library. So consider the answers presented on Jeopardy to which the contestant, human or Watson, needs to find the appropriate question to ask. In the case of the Jeopardy competition, either the individual memories of the participating humans had to find the correct question, or a technological artifact, Watson, had to find the correct question.

Normally, when someone needs to find a piece of information, they can either ask someone, or look it up in a reference, or search for it with a computer. In either case they are relying on transactive memory. If they know that the information exists someplace, that is termed available transactive memory. If they know where to find or whom to ask, then that is termed accessible transactive memory.

Given the ready availability of technology, one question is whether humans need to commit any information to personal biological memory if they can simply look it up or search for it. Of course, if no human commits any information to personal biological memory, asking other humans will not be an option. I would argue that the answer to this question is “no” for a couple of reasons.

Given the philosophy of the Healthymemory Blog, a healthy memory requires mental exercise, and committing information to memory is a good means of providing this exercise. This is true if mnemonic techniques are employed. Mnemonic techniques employ both hemispheres of the brain, and require imagination, creativity, and recoding. Now some Jeopardy contestants might employ mnemonic techniques some of the time, but I doubt that they are a major activity. Jeopardy contestants read widely. For material to be remembered, it needs to be meaningful. So much knowledge on a wide variety of topics has been linked together in their brains’ memory circuits. This activity also makes for a healthy memory. Moreover, most of the topics employed on Jeopardy are not trivia. Most represent substantive learning. However, even the learning of trivia can be healthy to the brain, as it does exercise the brain and build memory circuits. Although one might argue that the time could be better spent, if the activity is enjoyable that should be justification enough.

Nevertheless, given the wide availability of technology, there is a serious educational question here. Historically, most learning has been assessed by determining how much material has been memorized via true false, multiple choice, fill in the blank, or essay questions. Is this still the best way to assess learning? Rather than assessing what knowledge has been memorized, might it be better to assess how well a student can use this knowledge. In this case, there might be no need for closed book tests, and students might be given access not only to their own notes, but also to the internet. Exam questions would require them to solve problems given access to all these resources. Of course, giving citations for the sources of material should be a requirement.

I don’t know the answer to this question. The stage of education and the type of material are relevant considerations. But testing does need to be reconsidered given the new technology.

When we encounter new information we are confronted with several questions. One is whether the information has any interest or relevance. If the answer is yes, then the question is how much attention needs to be paid to it. Does it need to be committed to personal biological memory? Or do I simply need to know how to access or whom to ask, when this information is needed? 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Buddha’s Brain

February 13, 2011

Buddha’s Brain: the practical neuroscience of happiness, love, and wisdom1 is not a book proselytizing Buddhism. Its authors are Rick Hanson, Ph.D., and Richard Mendius, MD, who are a neuropsychologist and a neurologist, respectively. They address the intersection of three disciplines: Psychology, Neuroscience, and Contemplative Practice. In doing so, they avail us of wisdom from the East, wisdom that is not addressed by the West, in general, and by the Western educational system, in particular. Buddha’s Brain provides readers with a great deal of potential for cognitive growth and personal fulfillment.

Here are some basic facts from Buddha’s Brain. The brain consists of about 1.1 trillion cells, 100 billion of which are neurons. The average neuron receives about 5,000 connections, synapses, from other neurons. Chemicals called neurotransmitters carry signals across these synapses. A typical neuron fires from 5 to 50 times a second. The number possible neurons firing or not firing is about 10 to the millionth power (1 followed by a million zeroes). Now the number of atoms in the universe is estimated to be about 10 to the eightieth power. Conscious mental events, which represent a small percentage of brain activity, are based on temporary coalitions of synapses that form and disperse. Although the brain is only about 2 percent of the body’s weight, it consumes from 20 to 25 percent of the bodies oxygen and glucose. The brain is constantly working and uses about the same amount of energy whether you are sleeping or thinking hard. The brain interacts with the rest of your body and is shaped by the mind as well. Your mind is made by your brain, body, and natural culture as well as by the mind itself.

Buddha’s Brain covers the structures of the brain and neurotransmitters and explanations of what does what and how the different structures interact. More importantly, Buddha’s Brain explains how you can affect these structures and processes and mold your own brain and behavior. Readers of the Healthymemory Blog should know the importance of attention and selective attention to effective memory. Buddha’s Brain covers how to control and expand attention as well as how to control your emotions to lead to, as the title promises, happiness, love, and wisdom. People who are deeply into contemplative practices are able to control heart rate and blood pressure.

One prediction that I have read, and which I believe, is that within twenty years meditative practices will have become as frequent as aerobic exercising is today.

Some future blog posts will be based on excerpts from Buddha’s Brain, but they cannot do justice to the entire book. I strongly recommend its reading.

1Hanson, R., & Mendius, R. (2009). Oakland, CA: New Harbinger Publications, Inc. 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Google vs. Facebook Revisited

February 9, 2011

A number of blog posts back I expressed disappointment that Facebook had replaced Google in terms of usage. The stated grounds for my disappointment was that Facebook consisted primarily of superficial postings. True, they are enjoyable and fun, but little is learned and there is little cognitive growth. Although it is true that there are trivial searches on Google, a Google search is more likely for some useful point of knowledge. So, according to my line of reasoning, Google users were more likely to benefit from cognitive growth than were Facebook users.

In retrospect, I think that I might have been a bit unfair with my Facebook criticism, even though I did admit that many professional organizations are on Facebook. This blog post falls into the category of transactive memory. Now if you search for transactive memory on the Wikipedia (or you can search for it on Facebook that will link you to the Wikipedia) you will find that it is memory shared among a group. Actually the Healthymemory Blog is waging a rather lonely vigil by including the other meaning of transactive memory, namely, information that is found in all forms of technology (the internet, but also in conventional libraries). Although I do think that Google provides a more ready entry to transactive memory in the sense of technology, Facebook provides an entry to transactive memory in terms of memories shared with people.

I should also note that cognitive growth does not require delving into deep academic topics. For purposes of a healthy memory, information about sports and movies can form new memory circuits and reinvigorate old memory circuits in the brain. So the important point is to be cognitively active. In this respect Facebook can be quite helpful. It can serve as a resource for sharing information and collaborating with fellow human beings.

Personally, I provide a poor example. The Healthymemory Blog does have a Facebook posting, but I have done nothing with it, so it is rather sparse. I am interested in any experiences readers of this blog might have had in using Facebook in learning about topics of interest and in sharing information regarding those topics of interest. Please leave your comments. 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

A Day in the Life of Mr. and Mrs. Healthymemory

February 6, 2011

Mr. and Mrs. Healthymemory are a retired couple who are interested in memory health and stay mentally active. The following is a summary of a typical day in their lives.

They sleep in as they are careful to be sure that they get enough sleep. During breakfast the share the morning paper and discuss topics of mutual interest. They include flavonoids in their breakfast as they do with all their meals (See the Healthymemory Blog Post “Flavonoids for a Healthy Memory”). They discuss their plans for the day both to assure that they are efficient (they are not making unnecessary trips or taking routes that are time consuming) and mutually supportive (their plans fit well together). They commit both their plans to prospective memory so that each know where the other will be at what times. They use mnemonic techniques to commit their plans for the day to memory. They don’t feel a need to use technical transactive memory (to write the plans down or enter them into a Personal Digital Assistant) because they are confident that they will remember and that nothing catastrophic will result in the event that either forgets something.

Mrs. Healthymemory prepares to leave to go to the supermarket. Again she chooses not to write down a shopping list, but rather uses a mnemonic technique to commit the list to memory. Mr. Healthymemory goes to the computer to work on a history of their families. Currently, he is using geneological websites to see how far back he can trace their family histories.

Later in the morning, they take a walk before lunch, recognizing that physical health is important to a healthy memory. During lunch they converse about topics of mutual interest.

In the afternoon they meet with their separate friends. Mrs. Healthymemory meets with her book discussion group. Her group not only discusses the book, but also does research online regarding the author, critiques of the book, and about the context in which the book takes place. So in addition to reading the book, each member spends time doing research online and preparing presentations to the group.

Mr. Healthymemory is in a sports trivia group. Currently they are researching the history of baseball. Most of this research is done online. This research involves numbers in addition to names. They are especially interested in how such statistics as batting averages, home runs, complete games pitched and earned run average have changed over time and have animated discussions regarding possible reasons for these changes.

During dinner they discuss their respective days. Each makes an effort to understand some of the interests of the other in the interests of fostering mutual transactive memories. This is beneficial both to their respective memories and their relationship. They also discuss strategy for the bridge games they have planned with another couple for the evening. They have developed a fairly sophisticated bidding strategy using mnemonic techniques. Later that evening, they find that they are tired and ready for a good night’s sleep. 

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.

Walking and a Healthy Memory

February 2, 2011

The Health Day Newsletter contained an article1 summarizing a news release from the November 29, 2010 meeting of the Radiological Society of North America. The research suggests that walking about five miles a week may help slow the progression of cognitive illness among seniors already suffering from mild forms of cognitive impairment or Alzheimer’s Disease. The research also indicated that walking just six miles a week can help prevent the onset of disease.

Two appealing features leap out at me from this news. First is the cost. Walking costs nothing (unless you choose walking shoes or consider the minimal wear placed on shoes). Secondly, this is a reasonable regimen. Six miles is not excessively demanding, particularly when you consider that it can be spread out over an entire week.

3-D MRI scans were done to measure brain volume. After accounting for age, gender, body-fat composition, head size, and education, it was found that the more the individual engaged in physical activity, the larger the brain volume. Greater brain volume is a sign of a lower degree of brain cell death as well as general brain health. Cognitive tests were also administered and these also indicated improved cognitive performance in healthy individuals and lower losses in cognitive performance for those who already had begun to decline cognitively.

Physical activity improves blood flow to the brain, changes neurotransmitters, and improves cardiac function. It also lessens the risk of obesity, improves insulin resistance and lowers the risk of diabetes, and lowers blood pressure, All of these things are risk factors for Alzheimer’s disease.

Clearly the Healthymemory Blog endorses physical activity in addition to the mental activities advocated in this blog. These include mnemonic techniques and transactive memory. Transactive memory entails cognitive growth via technology and our fellow human beings.

1Regular Walking May Slow Decline of Alzheimer;s, http://consumer;healthday.com/Article.asp?AID=646656

© Douglas Griffith and healthymemory.wordpress.com, 2011. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Douglas Griffith and healthymemory.wordpress.com with appropriate and specific direction to the original content.