Posts Tagged ‘The Brain’

What Are the Consequences of Having Only Half a Brain?

December 28, 2015

We actually have the answer to this question as the result of the unfortunate circumstance in which a young girl found herself (this can be found in Eagleman’s “The Brain”).  As a result of the damaging consequences from a disease she was suffering, it was necessary to remove an entire half of her brain.   And what were the consequences from this surgery,  She is weak on one side of her body, but otherwise she’s essentially indistinguishable from other children.  She has no problems understanding language, music, math, and stories.  She’s good in school and participates in sports.

When I was a graduate student I remember reading a study about a man who has a result of hydrocephalus had only 10% of the volume of a normal cortex.  Nevertheless, he not only was able to lead a normal life, but earned an bachelor’s degree in mathematics.  Should anyone no a reference for this study, please comment.  It was in the early 1970s and in the journal Science, I believe.

Then there is the research described in the books by Doidge (enter Doidge in this blog’s search block).  Neuroplasticity as reflected in the brain’s ability to heal itself is truly phenomenal.  There are frequent mentions of individuals whose autopsies indicated that they had the defining neurofibril tangles and amyloid plaque that defines Alzheimer’s, yet never exhibited any symptoms or cognitive deficits of the disease.  This finding has been accounted for by saying that these individuals had a cognitive reserve that overcame these potential debilitating characteristics.  So the recommendation of the healthy memory blog is to undertake a lifestyle that not only prevents Alzheimer’s, but also leads to a more satisfying life.

It seems that most of the research on Alzheimer’s is aimed at detecting the plaque or tangles early, identify relevant genes, sor in slowing the growth of these features.  I would appreciate some work that attempts to capitalize on the brain’s neuroplasticity.

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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.

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Brain, Mind, Memory

November 22, 2015

These are three terms that are sometimes used interchangeably, but each has distinctive meanings.  The term brain certainly has the most prestige,  Someone who is known as a researcher of the brain has more prestige that someone who is known for studying the mind or memory.  The study of the brain, neuroscience, is regarded as hard science, whereas the study of either the mind or memory is regarded as soft science.

The adult brain weighs about three pounds, has the consistency of firm jelly, and has a wrinkled performance (deep valleys carving a puffy landscape).  There are an average of 86 billion neurons in the adult male brain.  These neurons are connected by about fifty trillion synapses.  Research is underway to map the brain.  The complete mapping of the brain would be an enormous achievement for anatomy.  But apart from anatomy, what would it tell us?  If we had a detailed understanding of how the brain worked, we would have important information, but we would not understand what the brain does.

The primary accomplishment of the brain is that it provides the physiological substrate of the mind.  We are aware of the conscious component of the mind, consciousness.  But most of the mind lies below the level of consciousness.   It is constantly working, even when we are asleep, although we remain unaware of what it is doing.  It is the mind that is of primary interest.  David Eagleman titled his book, “The Brain:  The Story of You.”  Eagleman is an neuroscientist and can title the book how he likes.  I am a psychologist and I would prefer “The Mind:  The Story of You.”  Of course, the brain is important as it constitutes the physiological substrate for the mind.

I believe that memory is thought of by most people as a place where information is stored.  Usually the complaint is that their memory is poor because they forget things.  Memory is central to the mind and to cognitive processing.  Remember that in the visual system there are ten times as many neural pathways going down from the brain as their are pathways proceeding up from the eyes.  Memory is involved in the processing of all incoming information.  This provides for the rapid processing of information, but it also leaves us vulnerable to our many biases and preconceptions.

Memory is involved in more than retrieval of information from the past.  It is a device for time travel where possible futures, dangers, and opportunities can be imagined.  Perception is never immediate.  Incoming data is first stored in a very short term store (hundreds of milliseconds in the iconic storage of visual memory), then a selective portion of this information is processed into working memory where it becomes consciousness.  Whether the information is stored so that it can be remembered is largely a function of how much and how effectively attention has been applied to the information.  Once stored, there is a distinction between memory that is available in memory, and information that is accessible in memory.  Information that is accessible is readily recalled.  Information that cannot be recalled is likely available in memory but cannot be accessed at a particular time.  The healthy memory blog post “The Myth of Cognitive Decline”  explains that the slowness of recall and the apparent loss of memory is primarily due to the enormous amount of information stored in the elderly brain.  There is much more to search through than in younger brains, so it is often slower and can appear to be faulty.  However, often when you fail to recall an item, your non-conscious memory continues to search for it, and it might pop into your consciousness a day later or even more.

It is more accurate to say that the mind recreates rather than recall memories.  Memories are not exact copies of prior experiences.  Moreover the act of recall improves the likelihood that the memory will be accessible in the future.  This is why when studying it is important to try to recall information rather than simply reviewing.  Testing provides the basis for improving memory.

So we cannot underestimate the importance of memory, and the healthy memory blog is devoted to keeping memories healthy.

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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 Single Shifting Mega-Organism

November 19, 2015

A single shifting mega-organism is how Dr. Eagleman describes our species in “The Brain.”  He does this because we are a social species, and an enormous amount of brain circuitry has to do with other brains.  Consequently  we have a new field of research, social neuroscience.  I would add that our shifting mega-organism includes not only the living, but also the dead.  Through the artifacts of technology, we can can learn from those who have passed away.  Information resident in technology and in our fellow human beings comes under the general rubric of transactive memory.

Throughout our lives, our brain circuitry decodes the emotions of others based on extremely subtle facial cues.  Research has shown that people viewing a photo of a smile or a frown, produced short periods of electrical activity  that indicated that their own facial muscles were moving, effectively mirroring the smile or frown that they were viewing.

There is a pain matrix in the brain where pain is processed.  The precipitating event activates different areas of the brain operating in concert to produce the feeling of pain.  When you watch someone in pain, the parts of your pain involved in the emotional experience of pain are also activated.  This provides the basis for empathy.  You literally feel the other person’s pain.  We are able to step out of our shoes and into the shoes of another, neurally speaking.  Empathy is an important skill.  Having a better grasp of what someone is feeling gives a better prediction about what they’ll do next.  This is true of social pain as well as physical pain.  Social pain activates the same brain regions as physical paint.

If empathy worked all the time, then we would be a much more functional species.  Unfortunately  this single shifting mega-organism  exhibits warfare between and sometimes among different parts.  Outgroups are identified for violence even when those outgroups are defenseless and pose no threat.  This violence has occurred throughout recorded history and likely before history was recorded.  Starting in 1915 more than a million Armenians were killed by the Ottoman Turks (accurately portrayed in the movie “The Cut”).  The Japanese invaded China and killed hundreds of thousands of unarmed civilians in 1937.  Then there was the infamous German killing of many millions of Jews in the holocaust during World War 2.  In 1994 the Hutus in Rwanda killed 800,000 Tutsis, many with machetes.  Between 1992 and 1995 during the Yugoslavian War over 100,000 Muslims were slaughtered in violent acts known as “ethnic cleansing.”  In Srebrenica over the course of ten days, 8,000 Bosnian Muslims were shot and killed after the United Nations commanders expelled them from the compound in which they had sought safety.  Women were raped, men were executed, and even children were killed.  Today we regularly see atrocities committed by ISIS.

Itzhak Fried, a neurosurgeon, has called these atrocities examples of Syndrome E (E for Evil).  Syndrome E is characterized by a diminished emotional reactivity, which allows repetitive acts of violence.  It includes hyperarousal, which is a feeling of elation in doing these acts.  There is group contagion.  Everyone is doing it, and it catches and spreads.   Compartmentalization exists in which one can care about his own family yet perform violence on someone else’s family.   This suggests that this is not a brain-wide change, but instead involves areas involved in emotion and empathy.  So a perpetrators choices are run by the parts of the brain that underlie logic, memory, and reasoning, but not the networks that involve emotional consideration of what it is like to be someone else.  According to Fried, this equates to moral disengagement.  People are no longer using the emotional systems that under normal circumstances steer their social decision making.

So, now we have a name and an explanation.  What is needed is a means of prevention or a cure!

© Douglas Griffith and healthymemory.wordpress.com, 2015. 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.