Archive for August, 2010

A Most Remarkable Example of Neuroplasticity

August 29, 2010

The topic of neuroplasticity has been discussed on a number of Healthymemory Blog Posts including one specifically titled “Neuroplasticity.” A recent issue of New Scientist contained a report1 of one of the most remarkable examples of neuroplasticity. People who have lost their sight are learning to see with their ears.

This is not the first time that people have reported a kind of seeing through another modality. In 1969 the neuroscientist Bach-y-Rita rigged up a television camera to a dentist’s chair. A 20-by20 array of stimulators that translated images into tactile signals by vibrating against the participant’s back was positioned on the chair. This allowed blind participants to detect the presence of horizontal, vertical and diagonal lines. Skilled users could even associated the vibrations with faces and common objects. Bach-y-Rita continued to develop even more sophisticated devices that translated a camera’s images into electrical pulses delivered by a postage-stamp-sized array sitting on the tongue. After some practice users found that these pulses gave them a sense of depth and openness. They had a feeling that something was out there.

The latest device, named vOICe, uses sound rather than tactile stimulation. Peter Meijer thought of the idea in 1982, but it took until 1991 to build a desktop prototype. The user wears a pair of sunglasses mounted on a webcam that captures the scene in front of her. The image is sent to a computer that converts the picture into a series of sounds called a soundscape. The vOICe software scans across the scene from left to right converting each pixel into a beep. The frequency represents the vertical position of the pixel and the volume represents the brightness of the pixel. The soundscape is played into the user’s ears. Initially the brain’s auditory cortex tries to make sense of the soundscape. However, after ten to fifteen hours of training regions of the visual cortex begin to light up. So the data is being redirected to the part of the brain that interprets visual images. At about the same time that the visual cortex becomes active the users become more adept at understanding the soundscapes and recognizing objects. Of course, this is being done no where near as quickly at normal vision. However, users are able to see the environment and the experience is qualitatively similar to seeing. One user provided this description. “It’s like looking at a black-and-white movie from the 40’s. I can see the tree from top to bottom, and the cracked sidewalk.”

To this point the users have been individuals who once did see, but then lost their vision. So when they make statements that it is like seeing, it is related to past experience. The device is currently being tried by congenitally blind individuals. A key question is whether they can learn to use the device. If they can, this “seeing” will be a new experience for them.

This type of substitution should allow people to adjust to sensory losses. The capacity to recover lost functions is much greater than was formerly believed. This research shows that the ability to learn does not disappear as we grow older.

1Trivedi, B. (2010). Ear today, eye tomorrow. New Scientist, 14 August, 42-45.

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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 Dementia an Inevitable Part of Aging?

August 22, 2010

This blog post is another in the series inspired by the book, The Scientific American Brave New Brain.1 That book presents a table contrasting the way the brain once was regarded, the way it is presently regarded, and some conjectures about what tomorrow might hold. According to Brave New Brain in the past, Alzheimer’s Disease and loss of brain function were regarded as inevitable parts of aging. Although the awareness of the widespread plague of Alzheimer’s Disease is relatively knew, many if not most people regarded the loss of brain function as a normal part of aging. It was thought that just as the body wears out, the brain wears out.

According to Brave New Brain today it is believed that “active brains retain more function than inactive ones, even to some very elderly people.” Even as parts of the brain decline, the neuroplasticity of the brain results in the enlisting of other parts of the brain to compensate for this decline. The Healthymemory Blog post “HAROLD” discussed this compensation. An important part of the current belief is that active brains retain more function than inactive ones. That is, inactive brains do decline as a result of aging. So here the old belief maintains. If you are passive and mentally inactive you can expect to lose brain function. The brain is analogous to the body: use it or lose it.

According to Brave New Brain, in the future Alzheimer’s disease is reversible and curable in many cases. Let us hope that this is also true for other forms of senile dementia. The question is how far into the future will this be the case. Are all of us baby boomers safe. I’m afraid that already some of us baby boomers have succumbed. Will the tale end of the baby boomers be safe? Let’s hope that cures and effective treatments will be developed as soon as possible. Otherwise the effects will be truly devasting.

The good news is that we do have a fighting chance. Active brains retain more function than inactive ones. Although there is no absolute guarantee that an active brain will not succumb Alzheimer’s or some other form of dementia, but the odds of succumbing are decreased by staying mentally acted. Moreover, you have the option of increasing your mental activity. Even if a cure for dementia were found, and let us up that there will be a cure, keeping mentally active and growing cognitively are still worthy goals on their own. They should result in a richer, fuller life.

The Healthymemory Blog is devoted to promoting healthy mental activity. It has three themes. One is the provision of knowledge about how memory works and how it fails to work. And it offers remedies for these failures. The blog posts are found in the Memory: Theory and Data category. Another theme is the use of mnemonic techniques. These posts are found, appropriately enough, under the category of mnemonic techniques. These techniques not only provide a means of improving memory, but also provide exercise that keeps the brain active. It is recommended to start at the beginning, bottom of this category as techniques become more difficult as you advance upwards. The third theme is Transactive Memory. Blog posts under this category provide suggestions for using technology and other people not only to maintain cognitive health, but also to foster and extend cognitive growth well into old age.

1Horstman, J. (2010). San FranciscoJossey-Bass.

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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.

Epigenetics

August 18, 2010

This blog post is another in the series inspired by the book, The Scientific American Brave New Brain.1 That book presents a table contrasting the way the brain once was regarded, the way it is presently regarded, and some conjectures about what tomorrow might hold. According to Brave New Brain, we once thought that environment determines mental potential and that today we think that genes determine mental potential. Here I must take strong exception to Brave New Brain. There were some philosophical arguments that the mind began as a blank plate, tabula rasa, and that experience was written on that plate. The father of behaviorism, John Watson, argued that he could take an infant and raise it to be anything, a butcher, a baker, a candlestick maker, a physician, a lawyer, another psychologist. For him the environment determined everything and that if the proper environments were provided a child could become anything.

Even before Mendel discovered genes, there was the notion of blood and royalty. Certain people were regarded as inherently superior to others. When genes were discovered, some thought that there might be a scientific basis for this superiority, and that genetics could account for individual differences. According to Brave New Brain, that is the current belief. This is certainly not the case. Early in the twentieth century intelligence tests were developed. Arguments as to know much intelligence is attributable to genetics and how much intelligence is attributable to the environment raged. Charges of racism entered these arguments and charges and evidence that IQ tests were culturally biased raged. It should be noted that there are statistical techniques and research designs (controlled identical twins studies, for example) that allow estimates of what percentage of intelligence is genetically determined and what percentage is due to the environment. But these are statistical abstractions. Nature (genetics) and nurture (environment) are inextricably intertwined; they never appear in isolation.

The recent birth of the study of epigenetics has highlighted the interaction between the environment and genetics. The genome cannot be considered alone. Another layer of information stored with the genome is called the epigenome. It is a chemical switch that determines which genes are activated and which genes remain dormant. It does not alter the genetic code, but affects the specific expression of genes. It shuts down or revs up the production of proteins that affect mental states.

Today we know the role of epigenetics. The question for the future is how well can we develop our understanding of epigenetics and whether we can use it to enhance brain function. Research using mice provides reasons for optimism. One study involved mice that were born with genetic disorder resembling mental retardation. They were given a drug that activated epigenetic activity three hours before a training session. They exhibited no learning problems. So perhaps someday mental retardation might be remedied via epigenitic manipulation.

Drugs are not necessarily required for epigenitic manipulation. Researchers at MIT restored mouse memories by enriching the rodents environment. Not only were memories restored but evidence of epigenetic activity was found. Research on the benefits of enriching environments was done years ago, but that was before anyone had ever heard of an epigenome.

1Horstman, J. (2010). San Francisco” Jossey-Bass.

The Accuracy and Malleability of Memory

August 15, 2010

This blog post is another in the series inspired by the book, The Scientific American Brave New Brain.1 That book presents a table contrasting the way the brain once was regarded, the way it is presently regarded, and some conjectures about what tomorrow might hold. According to Brave New Brain, we once thought that memory is accurate and unchanging. This statement is itself inaccurate and oversimplistic. Gestalt psychologists believed that memory was governed by autocthonous forces which moved memories to a good form, basically improving on them. The British psychologist Sir Frederic Charles Bartlettt conducted research on the memory of prose stories and how they were altered during recall. The research was reported in his book, Remembering (1932). I don’t believe that anyone ever held that memory was entirely accurate and unchanging. Forgetting and errors in recall could not be ignored. In the popular culture there was a belief that memory was like a video tape of your life. I do not believe that memory researchers held to this view. The brain surgeon Wilder Penfield, during the course of brain surgery, would electrically stimulate a part of the brain and the patient would start recalling an event that presumably happened, say a birthday party, in vivid detail. This made its way into the popular culture. This belief also led to a belief in truth serums or in hypnotic trances that presumably would allow the accurate read out of this videotape. All of this has been thoroughly debunked, but you will still find it in movies and novels. It is nonsense.

According to Brave New Brain, today the belief is that memory is changeable and that events are “recollected” in a new context and slightly changed. I would revise this statement to read …that memory is more changeable and that events are “recollected” in a new context and changed, sometimes quite markedly. Current research has shown that memory is quite malleable, and that events can be implanted and believed that never occurred2. Eyewitness testimony has been shown to be quite fallible. Many have been falsely imprisoned and sent to death row to the mistaken confidence placed on eyewitness testimony by the courts and juries3.

According to Brave New Brain tomorrow, “Memory is manipulated. You can keep the memories you want and erase the ones you don’t.” I would argue that today many of us already do this. We tend to remember and believe that we did better than we actually did and that we are more liked that we actually are. Presumably Brave New Brain is referring to futuristic manipulations using chemicals, electrical, or magnetic stimulation that would allow such manipulations. Such interventions could be quite helpful for those suffering from frightening memories, depression or low self esteem, but they could be dangerous to the majority of us. Memories, sometimes painful, of what we’ve done wrong or who we might have offended are critical to learning and making necessary adjustments to our thoughts and .behavior. Someone choosing to eliminate all negative or painful memories would be well on the way to becoming a world class jerk, at best, or a sociopath, at worst.

1Horstman, J. (2010). San Francisco” Jossey-Bass.

2Loftus, E. (1997). Creating False Memories. Scientific American., 277, pp. 70-75.

3Loftus, E. (1979). Eyewitness Memory. Cambridge, MA: Harvard University Press

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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.

Stroke: Then, Now, and Tomorrow

August 11, 2010

This blog post is another in the series inspired by the book, The Scientific American Brave New Brain.1 That book presents a table contrasting the way the brain once was regarded, the way it is presently regarded and some conjectures about what tomorrow might hold. Formerly stroke damage was regarded as mostly irreversible. It was believed that if improvement was not seen after several months, it would never be seen. Unfortunately, this prognosis was dictated by the then current view of the brain, that brain cells cannot be replaced when they die and that the brain is hardwired and cannot be changed. The debunking of these views was covered in the preceding blog posts, “Neurogenesis,” and “Neuroplasticity.”

Given our current understanding of the brain regarding both neurogenesis and neuroplasticity, the potential recovery of stroke victims has become optimistic. Research and clinical results have confirmed this optimism. Now treatments are undertaken that would never have been considered under the previous views of the brain. Moreover, treatments are undertaken for much longer periods as it has been shown that stroke victims can regain functions even years after a stroke with ongoing therapy. A previous Healthymemory Blog post, “Transactive Memory: An Aid to Short and Long Term Memory and to Stroke Recovery,” expounds, as the title indicates, on how transactive memory can aid in stroke recovery.

According to Brave New Brain, the future will bring new technologies to prevent damage, renew damaged areas, and replace neurons. One particularly interesting project discussed in the book is the development of an artificial hippocampus. One cannot overemphasize the important role the hippocampus (actually there are two hippocampi, one in each hemisphere of the brain) plays. Perhaps important role is in the long term storage of memories. If the hippocampus does not function properly, new memories are no longer formed (enter “hippocampus” into the search box to find more Healthymemory Blog Posts discussing the hippocampus.).

One should not underestimate the difficulties this project needs to address. First of all, it needs either to identify information to be stored in long term memory or to have this information pre-identified. Storing everything in long term memory would be overwhelming and stultifying. Then you would need to learn how to code the information for memory storage. Finally, you would need to know where to send this information. It is likely that it would need to be sent to many places in the brain. Moreover, the where to send requirement would probably be determined or influenced by the kind of information to be stored. An effective artificial hippocampus probably remains something to be developed in the distant future, if it is ever developed. Nevertheless, it is an important structure, one that certainly warrants investigation. What is learned, even given the ultimate failure of the project, could be quite valuable in our understanding of how human memory works.

1Horstman, J. (2010). San Francisco” Jossey-Bass.

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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.

Brain, Mind, and Body

August 7, 2010

This blog post is another in the series inspired by the book, The Scientific American Brave New Brain.1 That book presents a table contrasting the way the brain once was regarded, the way it is presently regarded and some conjectures about what tomorrow might hold. This blog also draws upon a recent book published by National Geographic,2 which will be reviewed in a subsequent post.

According to The Scientific American Brave New Brain, brain, mind, and body are separate. Now this was true quite some time ago. According to the National Geographic book, the ancient Egyptians thought the brain to be worthless, thinking that the heart contained the soul and the mind. Although there seemed to be some dispute regarding this among the ancient Greeks, Hippocrates wrote that “The eyes and ears and tongue and hands and feet do whatsoever the brain determines. It is the brain that is the messenger to the understanding [and] the brain that interprets the understanding.” So it was fairly long ago that it was believed that the brain and the body were linked.

Apparently, it was not until Descartes came along that the mind was addressed. His famous cogito ergo sum, I think therefore I am, made the mind central. External reality was not known directly but rather was interpreted in the mind. Good science, as well as successful negotiations with and in the environment are dependent upon our internal reality being in some correspondence with external reality. There still is some question as to what is meant by mind. Is it consciousness? What role does it play. Some might contend that consciousness is epiphenomenal, that it is like a movie playing in our head for our own entertainment. They would argue that the brain determines our decisions and behavior and that consciousness has no role. This is a rather extreme view that will be addressed in later posts. Brave New Brain contends that the current belief that brain, mind and body are intertwined and inseparable. That, indeed, is the current consensus.

Brave New Brain offers the conjecture that tomorrow brain, mind, and body are enhanced by machines and computers. Here a little thought might give rise to the question, “are not our brains and bodies already enhanced by machines and computers?” There are already seemingly countless machines aiding our bodies, and computers aiding our minds seem to be omnipresent. I believe that Brave New Brain is offering the conjecture of sci-fi type interventions of machines and computers along the lines of Kurzweil’s singularity.3 Kurzweil believes that in the near future technology will advance to the point where silicon chips will replace neurons, that we shall transcend biology and become effectively immortal. Kurzweil himself has change his lifestyle and diet to extend his life to the point where technology will be ready to take over before he dies.

It should be noted that an enormous leap is involved here. We have the conscious experience of our own senses and minds. And we can look at electronic recordings of our minds and senses and view brain images of our mind and senses. Nevertheless, we have no understanding of how this occurs other than to say our consciousness is an emergent phenomenon. Whether consciousness will emerge from silicon is a very large question indeed.

1Horstman, J. (2010). San Francisco” Jossey-Bass.

2Sweeney, M.S. (2010). Brain The Complete Mind: How It Develops, How It Works, and How to Keep It Sharp.

3Kurzweil, R. (2006). The Singularity is Near: When Humans Transcend Biology.

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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.

Neuroplasticity

August 1, 2010

This blog post was inspired by the book, The Scientific American Brave New Brain.1 When I was a graduate student I learned that the brain was hardwired like a machine or a computer (which were much less common in those days). This was dogma that was not challenged. It was widely accepted and affected the way that people who suffered strokes or other brain traumas were treated. The belief was that once the damage was done, little more could be done than to teach the victim how to deal with the remaining functionality that was left. Recent research has refuted this dogma and the term neuroplasticity has become the norm. The brain is remarkably plastic or flexible. And if one part of the brain is damaged, another part of the brain can frequently take over that function. An earlier Healthymemory blog post, “Transactive Memory: An Aid to Short and Long Term Memory and to Stroke Recovery” addressed some issues regarding stroke, and subsequent posts will address it further.

Brave New Brain states that the current consensus is that “your brain is changing every second in response to the environment and mind.” The Healthymemory Blog strongly concurs. Brave New Brain also states that tomorrow you change and mold your brain as you want and need. Now here the Healthymemory Blog would argue that already today you can change and mold your brain as you want and need. Indeed, if the brain is changing every second in response to the environment and your mind, you can change and mold your brain by selecting the environment in which it operates and the manner in which your mind wakes. Presumably Brave New Brain is implying that the future will bring technology, for example chemicals or electronic means of stimulating the brain, that will facilitate your changing and molding your brain as you want and need. The prospects of this happening will be discussed in future posts, but you need to realize that today you can change and mold your brain as you want and need. True there are limitations. You might want to change your brain so that you can invent means of travel that exceed the speed of light. Nevertheless, your brain holds enormous potential that you should not overlook.

This admonition certainly applies to young people. However, it also applies to older people, including we Baby Boomers. We are not done learning. Our goal should be not only to ward off cognitive decline and dementia, but to continue to learn, create, and grow cognitively. We can change and mold our brains by choosing how we apply them. There are vast resources available in what the Healthymemory Blog terms transactive memory. Transactive memory refers to all the information that is external to your own biological brain. Included here is the information stored in the biological brains of other humans, and all the information stored in the libraries of the world, and, of course, the internet. There are three types of transactive memory. Accessible transactive memory is information that you know exists and can readily access. Available transactive memory is information that you know exists but that you cannot readily access. This is information that needs to be searched for and sought. Then there is potential transactive memory, which is all the information you have not yet discovered. You should note that the Healthymemory has a whole category of posts on transactive memory.

You should also note that there is another category of Healthymemory Blog posts on Mnemonic Techniques. Mnemonic techniques are specific strategies for learning difficult material, especially information that lacks or is deficient in inherent meaning. It is also believe that these techniques can serve as healthy mental exercises. The “Human Memory: Theory and Data” category includes posts such as this current one. As the title suggests it addresses human memory and also includes posts on common cognitive errors and how they can be avoided.

1Horstman, J. (2010). San Francisco” Jossey-Bass. 

© Douglas Griffith and healthymemory.wordpress.com, 2010. 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.