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Paradigm Example

Look at Brain Plasticity using quotes from Doige & What Have You Changed Your Mind About.

Paradigm Shift: Brain Plasticity

[This will be displayed as a sidebar when I figure out how to display sidebars. Currently it is embedded as a chapter topic but is Sidebar content type.] 

By happenstance, I found an excellent example of scientific paradigm shift in two books unrelated to our subject (or each other for that matter).
 

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The fulcrum of this changing paradigm was the human brain’s malleability, often termed brain plasticity. Brain function was thought to relate to brain structure in the way movement was thought to relate to specific bones and muscles. If you lost a leg you could not generate another leg. It might be possible to use a combination of training and prosthetics to walk but organic damage in a particular location could make some activities flatly impossible.
 
In parallel, if a stroke damaged a particular brain center then the physical brain structures that embodied our ability to do some movements was thought to now be simply gone. We could perhaps work around those limitations but genuine recovery was not in the cards.
 
This paradigm was central to brain research. Before the current imagining tools that display activity in a living brain, the best way to match brain function to brain areas was to see what changed if a specific part of the brain was damaged. Movement in your left leg was directly dependent on an area of your brain the same way it was dependent on your leg muscles.
 
In the first of the two books, the inspiring The Brain that Changes Itself, Norman Doidge chronicles changes to this view.  He does this in many cases by visiting and interviewing import figures in the new paradigm’s origin.
 
First, Paul Bach-y-Rita.
 
In 1958 when Paul was already a professor at Smith-Kettlewell Institute of Visual Sciences, Bach-y-Rita's father, Pedro, suffered a major stroke which caused paralysis to one side of his body and damaged his ability to speak. Paul’s brother George (an architect in fact) created a rehab program that led to Pedro’s full recovery at a time when accepted wisdom considered that impossible and would have sent him to a nursing home.
 
The fact that he had made such a significant recovery indicated that his brain had reorganized itself: brain plasticity.
 
This led Paul to refocus, giving up an academic career in the field of eye movements, and switching to rehabilitation medicine at the Stanford Santa Clara Medical School.
 
Pedro’s  recovery was so complete that he resumed his job as a professor. He died at 72 from a heart attack, while hiking in the mountains of Columbia. On autopsy, portions of his brain stem showed severe damage that had not repaired itself.
 
Paul became instrumental in founding a new research paradigm.
 
As Doidge relates: [Link]
Bach-y-Rita began to think that the localization of "one function, one location" couldn't be right... He praised localization's accomplishments but argued that "A large body of evidence indicates that the brain demonstrates both motor and sensory plasticity." One of his papers was rejected for publication six times by journals, not because the evidence was disputed but because he dared to put the word "plasticity" in the title. After his Nature article came out, his beloved mentor, Ragnar Granit, who had received the Nobel Prize in physiology in 1965 for his work on the retina, and who had arranged for the publication of Bach-y-Rita's medical school thesis, invited him over for tea. Granit asked his wife to leave the room and, after praising Bach-y-Rita's work on the eye muscles, asked him--for his own good--why he was wasting his time…
 
Another pioneer, Michael Merzenich began by researching not visual but auditory systems. Specifically he began charting brain functioning using clusters of micro-electrodes embedded essentially in single neurons to explore the brain ‘maps’ that underlie auditory and other functioning. This allowed him to demonstrate that the connection between function and specific brain cells was fluid over time and was, in fact, continually being remapped. He could also demonstrate the variance between individuals.
 
Again from Doidge [Link]:
 
And yet despite the elegance of his experiment(s), opposition to Merzenich's ideas did not melt away overnight. He laughs when he says it. "Let me tell you what happened when I began to declare that the brain was plastic. I received hostile treatment. I don't know how else to put it. I got people saying things in reviews such as, 'This would be really interesting if it could possibly be true, but it could not be.' It was as if I just made it up."
 
This, of course, fits precisely with Kuhn’s description of how normal science responds at first to the revolutionary. Note also that, particularly in Merzenich’s case, exploring under one paradigm (function is hardwired to specific brain cells) gathered evidence that broke the old model and generated the new (brain ‘hardware’ is more generic and holds an ever changing relation to functionality.)
 
Robert Sapolsky in the second book, What Have You Changed Your Mind About? (edited by John Brockman and a book offshoot of the always interesting www.edge.org), relates the story from a different perspective.
 
First, Sapolsky relates the old paradigm, “Hey, the brain is so fancy and amazing that its elements are irreplaceable, not like some dumb-ass, simplistic liver that’s so totally fungible it can regrow itself. What this fact also reinforced, in passing, was the dogma that the brain is set in stone very early in life--that there's all sorts of things that can't be changed once a certain time window has passed."

Then he recounts the changes from a perspective focused on another component of brain malleability, “Starting in the 1960s, a handful of crackpot scientists cried in the wilderness about how the adult brain does make new neurons. At best, their unorthodoxy was ignored; at worst, they were punished for it. But by the 1990s, it had become clear that they were right. …And the phenomenon is a cornerstone of a new type of neurobiological chauvinism: Part of the very complexity and magnificence of the brain is how it can rebuild itself in response to the world around it."

Finally he relates his reactions, “I’ll admit that this business about new neurons was a tough one for me to assimilate. I wasn’t invested enough in the whole business to be in the crowd indignantly saying, “No, this can't be true!” Instead, I just tried to ignore it: “New neurons? I can't deal with this! Turn the page.” After an embarrassingly long time, enough evidence had piled up that I had to change my mind and decide I needed to deal with it after all. And it’s now one of the things my lab studies." [Link]

 
And, thus, the revolution is normalized.