Showing posts with label Begley. Show all posts
Showing posts with label Begley. Show all posts

Wednesday, December 12, 2007

History of Neuroplasticity

Matthias, I agree. And thanks for introducing Dean Kamen. Seems pretty clear his work designing arm prostheses that can "feel", will make the wider PT/OT rehab role lots easier. :)

You highlighted him as a good example of someone who is not afraid of "learning" and gave some of the important characteristics of that:
"creativity, an ability for lateral thinking, the ability to make connections between seemingly unrelated fields (of science) - and disrespect for authority."


I agree although I would translate "disrespect for authority" into "an ability to recognize and bypass conventional dogma or "groupthink" in favor of considered scientific reflection of all possibilities."

On the topic of neuroplasticity, Sharon Begley, in her book Train Your Mind, Change Your Brain, recounts how difficult it is for dogma to be overturned in favor of counter-information. She traces the history of the scientific study of neuroplasticity starting with William James, who said, in 1890: "organic matter, especially nervous tissue, seems endowed with a very extraordinary degree of plasticity", meaning, according to Begley, "a structure weak enough to yield to an influence". No one picked up on this at the time. Ramón y Cajal was in the forefront of neuroscience, and had dazzling, substantive, convincing and irrefutable research work to offer up. His opinion on fixedness, immutability, unchangingness in the nervous system was pretty much conflated with his actual research for the next century.

In the 1940's, Donald Hebb at McGill came up with
"When an axon of cell A is near enough to excite cell B and repeatedly or persistently takes part in firing it, some growth process or metabolic change takes place in one or both cells such that A's efficiency, as one of the cells firing B, is increased"

..which became known as Hebbian learning, and gave rise to the quip, "Neurons that fire together wire together."

Along came researchers like Fred Gage (a shirttail relative, apparently, of the famous Phineas, according to Begley), who runs a lab at the Salk Institute in La Jolla, California.

Starting in the 1960's, other researchers, like Joseph Altman at MIT, Michael Kaplan at Boston U., and Fernando Nottebohm who studied birds that produce new songs continually throughout their lives, William Greenough, showed evidence that went against dogma, but weren't able to budge it. Elizabeth Gould showed in the 1990's that primates demonstrated neurogenesis. Slowly, the dogma finally started to dissolve.

Then researchers tried to figure out how to show neuroplasticity exists in the human brain - they wanted to know not just if the human brain could rewire itself, but also if it could grow new cells. It was hard to deal with all the ethical dilemmas involved, but they finally got permission to look at brains of a group of people who were terminally ill, at autopsy. Specifically, Peter Eriksson and Fred Gage worked together to determine that new neurons are born constantly, even in the brains of old and sick humans. You can read more about how the dogma was made to melt down in this history module.

Suffice it to say, human neuroplasticity is a fact of life, and cannot be pushed back into the shadows. From a physiotherapist point of view, this is good news! It shows that our work, i.e., helping people, helping patients in pain, bolstering them and supporting their efforts to improve, now has irrefutable science to back it. Now we can show people studies (should we have to) to prove they can recover from even the most debilitating injury, but even more so we can turn around and challenge various dogmas that still exist right in our own profession, dogmas about pain and how best to help relieve it, help move the profession from one that is still mesmerized by structure into one that smoothly understands and supports function.

Tuesday, December 11, 2007

Neuroplasticity

Matthias, maybe we could start with neuroplasticity. One of the best sites online on this topic is On the Brain.com. The brain seems to be, basically, a big learning machine. One learns, slowly, to take control of its plasticity. The frontal lobes of humans are not fully formed until into the third decade of life.

What does neuroplasticity have to do with Pain?
You could say pain can happen if/when neuroplasticity gets out of control. Pain is noted as being a "dark side" of neuroplasticity. But, if the brain can learn its way into pain, it can learn its way back out.

I recently watched a PBS program (and took a few notes) on the topic of neuroplasticity in general and aging in particular - how to keep one's brain young, and how to help it if it became damaged. It featured Dr. Merzenich from the site mentioned higher up. According to the program, four fundamentals had to be in place for gaining control, "harnessing" this ordinary activity the brain does all the time anyway:

1. The focus, the inner attention, has to be on the process of learning the action, not the desired action itself.

2. The heart has to be in good shape. Cardiovascular capacity needs to be there. The brain needs lots of oxygen when it's in learning mode. Deep breathing can help.

3. Training must be incremental, and just a little bit taxing. (Does this not sound just like any form of "exercise"?) The brain will build itself best on a sense of consistent accomplishment.

4. The desired goal needs to be interesting.



The program listed seven tenets of neuroplasticity.

1. Change can occur only when the brain is in the mood: alert, on the ball, ready for action.

2. Change strengthens connections between neurons engaged at the same time. The brain builds on its successes.

3. "Neurons that fire together wire together" (-Donald Hebb, psychologist from McGill Uni. Montreal) This helps the brain get better at its predictive capacity. Associations can be made more easily.

4. Initial changes are just temporary. While the brain can learn through impact (a powerful experience), usually it learns through lots of repetition.

5. Brain plasticity is a two-way street; it can change itself in positive or in negative directions. E.g., chronic pain, bad habits

6. Memory is crucial for learning. Where you put your attention is important. Practicing something while distracted won't help the brain change.

7. Motivation is a key factor. The program told the story of Paul Bach-y-Rita's father, who sustained a huge stroke. Eventually he learned to get around, crawling at first - his motivation was that he hated being dependent. He gradually recovered most of his function! Later, after an autopsy, Paul Bach-y-Rita was able to see his own father's brain, could see how enormous the damage had been, and marveled at the recovered function his father had gained.


Also featured on this program was Sharon Begley, who has written a book called Train your Mind, Change your Brain, which I am currently reading. It reads like an historical novel, a huge wedge of perspective back through time into all the scientific background leading up to current research on neuroplasticity, some of the best neuroscience news in the last twenty years. In a nutshell: if your brain has "learned" pain, it can "unlearn" pain.

Matthias, I think each one of these points could probably grow into a whole post series, but I'll just leave it here for now. If you think this is a good jump off point, feel free to expand.

P.S. (Dec. 15):
Here are a couple of Dr. Ginger Campbell's podcasts on neuroplasticity:
Brain Science Podcast #10: Neuroplasticity- how our brains change throughout our lives - (discusses the Sharon Begley book, Train Your Mind, Change Your Brain)

Brain Science Podcast #26: More on Plasticity-an interview with Dr. Norman Doidge (Doidge has written a book on neuroplasticity called The Brain that Changes Itself.)