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I am reading William James' "Principles of Psychology". It is clear in his research that he was acutely aware of brain plasticity and the limited capacity for a precise "schema" (ie. static brain map) to represent brain function. Seeing that this text is well over 100 years old and cites much research even older, how is it that I see so much information (primarily in the press and lay neurology texts) that brain plasticity is a new perspective recently discovered by academics and researchers? Without question the earliest modern neuroscientists knew about brain plasticity. It was an undeniable characteristic of their research. (As a side note, it is interesting that creatures with less intelligence have greater plasticity, with the level of intelligence being inversely proportional to plasticity. A fact I've never seen discussed.)

I feel I should mention that I am not a psychologist or neuro-scientist. I have a doctorate in Statistics. I did search academic papers and there are many papers that credit William James with describing plasticity under the heading "habit". So to my original question, why is it that plasticity is just being "discovered?"

An academic paper that clearly sites William James with being the first to introduce plasticity - https://fastertomaster.com/the-brain-that-changes-itself-norman-doidge/

A recent book that erroneously claims plasticity is a new concept - https://fastertomaster.com/the-brain-that-changes-itself-norman-doidge/

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    $\begingroup$ What do those sources mean by "new"? How many years is "new"? $\endgroup$ – Bryan Krause Jul 31 at 15:16
  • $\begingroup$ I'd say this "neuroplasticity" phenomenon is a decade old now. So maybe only relatively new compared to the fact it was literally one of the first discoveries of modern psychology. I have only just read William James, so I would not have been able to make the observation during the height of the topic in pop culture. Although I have noticed many recent articles as well. $\endgroup$ – Hasselhoff Aug 1 at 17:18
  • $\begingroup$ The "new" or "rediscovery" of the neuroplasticity stuff at least dates to the 1970s. Note that in James' time we didn't quite know about neurons yet, so plasticity from a psychology standpoint is not the same as the "new neuroplasticity" - and it also isn't true that anyone ever thought the brain was completely fixed and couldn't learn: that's obvious. The new finding was just how much the brain could change in dramatic rather than incremental ways. AliceD's answer already covers this but it doesn't quite seem like you get it yet. $\endgroup$ – Bryan Krause Aug 1 at 18:00
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Short answer
Neural plasticity is a broad term. While it has long been recognized, the fact that the adult brain is plastic even at the gross structural level has taken a long time to become widely accepted.

Background
There are a few things that play a role here.

  • First and foremost, neural plasticity is a term encompassing many different processes. Neuroplasticity can be observed from microscopic (molecular) changes in individual neurons, to large-scale structural changes, such as cortical remapping in response to injury.
  • Secondly, the small scale changes have long been recognized, the gross structural changes were only discovered much later.
  • Thirdly, neuroplasticity has indeed been long recognized, but it has long been thought that there were critical periods in life (Sylva et al., 1997) where after plasticity was no longer present. In a way, that idea is still recognized, and is the reason why, e.g., congenitally deaf children are receiving cochlear implants in the first months of their lives to allow the plastic brain to develop hearing and speech development during this "critical period" where these developments are accompanied by gross changes in the brain not possible later in life (Snik et al., 1997). Untreated prelingual deafness therefore results in impaired speech understanding and the typical 'deaf speech' when they receive an implant after this critical period. Paul Bach-y-Rita and Michael Merzenich are often credited for their ideas on the plastic adult brain. For instance, Bach-y-Rita recognized that his dad, by then an aged man, was still capable to re-learn many tasks after serious brain injury. He recognized that hence, the adult brain is plastic too (plastic, in terms of gross changes that allow re-allocation of healthy brain tissue to take over the tasks from damaged regions). The idea of the adult brain being able for gross plastic changes has taken a while to become accepted.

References
- Snik et al., Int J Ped Otorhinolayngol (1997); 41(2):121-31
- Sylva et al., Br Med Bull (1997); 53(1): 185-19

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  • $\begingroup$ Interestingly, Merzenich is among those who have had a part in companies that tout this "new brain plasticity" mumbo jumbo that led to the OP's question. $\endgroup$ – Bryan Krause Jul 31 at 21:16
  • $\begingroup$ @BryanKrause - I wasn't aware of that. I always had Merzenich kind of high up in my ideas of brilliant folks. I might be biased, as a colleague of mine has worked with him for a while at his lab, and he was really enthusiastic about the experience. Can you link something to that 'mumbo jumbo' - I'm curious to learn more about that. $\endgroup$ – AliceD Jul 31 at 21:37
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    $\begingroup$ Yeah, his science historically is good and he did his work with Woolsey and Rose at my institution so he gets held up a bit here as well, and he also has some really good scientific descendants. brainhq.com He's defended his company as different from the others, e.g. briefly here: sciencemag.org/news/2014/10/… but at least on the surface it seems to be made of a lot of the same stuff. $\endgroup$ – Bryan Krause Jul 31 at 21:44
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    $\begingroup$ Merzenich did a post-doc in Madison. $\endgroup$ – Bryan Krause Jul 31 at 21:58
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    $\begingroup$ Thank you for this response. I would like to point out that any of the observations of plasticity in "Principles of Psychology" are on adult human brains and animals. Any research done on humans was primarily case studies of traumatic brain injuries. Just in the second chapter all the themes that you mentioned are suggested or explicitly observed (eg. gross structural change.) At the end of the day, the answer might just be that the community has rediscovered something that was lost. It certainly wouldn't be the first case. $\endgroup$ – Hasselhoff Aug 1 at 17:11
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The difference is that these days - it is known that plasticity (mainly) occurs in the synaptic connections, - the biophysical changes that implement the plasticity are known. - this knowledge allows manipulating and blocking of memory formation.

For instance in the 60s is was still thought that memory was stored in DNA.

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Some of the information contained in this post requires additional references. Please edit to add citations to reliable sources that support the assertions made here. Unsourced material may be disputed or deleted.

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    $\begingroup$ Welcome. Can you add sources to your claims? $\endgroup$ – AliceD Aug 2 at 22:47

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