A marvelous body of knowledge, theories, and technical advancements have occurred since the turn of the century when Eric Kandel won the Nobel prize. His life work was fundamental to the discovery of chemical processes that occur and change with short-term and long-term memory in all animals that have a nervous system; and particular in his scientific proof that the brain is not a static and hard-wired machine, incapable of changing – but a constantly adapting system capable of changing itself.

Numerous significant contributors have played a role in this growing body of accelerated understanding during the past two decades since this amazing discovery was officially documented and recognized, especially in consideration of the concomitant rapid technological advancements – particularly in relation to diagnostic imaging. It would be impossible to give comprehensive recognition to each contributor, and no attempt here is made to that end.

NOTEWORTHY CONTRIBUTORS

Exceptionally noteworthy colleagues include Dr. Norman Doidge, and Dr. Frederick Carrick. Interestingly enough, both are from Canada. Dr. Carrick’s contribution to the field of plasticity is considerable and substantial. Dr. Doidge’s contribution to plasticity is immense and far reaching.

Many decades ago, Dr. Carrick began training other practitioners – using the latest research available at the time – on techniques to restore brain function. Since the beginning of his career, he has trained thousands of medical practitioners, been awarded additional graduate diplomas from prestigious schools such as Harvard University, conducted his own breakthrough peer-reviewed scientific research with contributions to numerous noteworthy journals, founded a network of schools that train medical professionals throughout the world, and is a professor at a US News top-ranked school. His most important contributions have included his advancements in recovery of comatose patients, his work on balance and gait, and his unique perspectives and techniques regarding brain function and methodology for recovery.

Dr. Doidge is a psychiatrist who is best known for his book: The Brain the Changes Itself. With over a million copies sold, Dr. Doidge has helped countless people to understand what is possible in restoring the brain to its healthy state. He has received many honors – including literary honors, been featured on numerous video broadcasts, lectured at numerous well-known universities and prestigious organizations, and been featured by the best known news networks. In addition to helping make brain plasticity popular, Dr. Doidge has been involved with the creation of devices used to treat the brain, is a vibrant contributor to the body of scientific research, has devised methods for overcoming serious brain abnormalities, and has compiled an impressive volume of case studies regarding people whose brains have been healed through principles of neuroplasticity.

A PERSONAL INDULGENCE

It’s clear to see why both of these individuals have impacted the world in a positive and immeasurable way. I would now ask that you please forgive the personal indulgence. Both of these professionals are significant to me (Dr. Hogue), because Dr. Carrick was my professor almost two decades ago, and because I have been following and learning from Dr. Doidge for about 15 years.

BASIC PRINCIPLES

At least five components of brain plasticity are important for stroke recovery: NMDA receptor activation, physical exercise, psychological state, neurogenesis, and environment.

NDMA Receptor

The NMDA receptor is important for plasticity because this at least one of the mechanisms that is responsible for actually building the nerve connections. It’s important that we understand something about this receptor so that we can use that knowledge to intentionally build connections in the brain.

Closely connected to the NMDA receptor (and much more widely studied by researchers, because of its direct implications to pharmaceuticals) is the AMPA receptor. The AMPA receptor is what gets activated every time a nerve sends an electrical signal down its axon.

In order to get elicit activation of the NMDA receptor, the AMPA receptor needs to be elicited at a high intensity, frequency, and duration. When this is achieved, it causes a neuron to build a new connection to its target, at the rate of 1mm per day. The amazing thing about plasticity is that after the nerve cell has formed new connections to its targets, the changes are more or less permanent (with some exception)!

The reason it is necessary to get the neurons properly connected to one another is that information happens in real time. It is therefore necessary for the brain to work in conjunction with all of its parts, also in real time. Consider this excerpt from Doidge, 2007:

When we read, the meaning of a word is stored or "mapped" in one sector of the brain; the visual appearance of the letters is stored in another, and its sound in yet another. Each sector is bound together in a network, so that when we encounter the word, we can see it, hear it, and understand it. Neurons from each sector have to be activated at the same time — coactivated — for us to see, hear, and understand at once.

When certain parts of the brain become damaged, it’s not possible for the damaged portions to respond to their environment in real time. This requires the brain to make decisions or to draw conclusions from incomplete or inaccurate information.

Physical Exercise

A strong brain-body connection dictates outcomes in each. The brain contains numerous mappings of nearly every part of the body (somatotopic maps). These maps constitute a direct connection with the brain for movement of each muscle, sensation sin each skin region and in muscles & tendons, visual fields, and sensations of joint position. These are necessary for normal function, as well as in the controlling of the position of each body part in space, and in coordinated form with all other body parts.

It’s fantastic to consider that the brain needs to understand the tone on each muscle, with all the necessary changes that must take place to achieve any desired goal that requires movement of the skeleton. This is done by constantly monitoring the tone on each muscle group (incorrect muscle tone balance will injure the joints), creating precise motor plans, and then executing and monitoring progress. This process if fascinating.

However, things don’t always work correctly. People sometimes bite their tongue, trip on the sidewalk, have difficulty buttoning a shirt, or become unable to resist gravity. These symptoms could be caused by a variety of brain regions that work together, failures in the position-sense chain, or external factors such as extreme fatigue or drugs.

Position sense also involves pressure on joints (most importantly, while standing, the ankles), the multitude of sensation information provided by the inner ears, and information revealed by eye sight. When these systems produce contradictory information, the result can be devastating and sickening. However, with exercise, it’s important for these systems to function well. But, in addition to the fact that exercise is inherently good for the brain (and the heart, lungs, lymphatic system, kidneys, etc…), there are also chemical constituents of exercise important for plasticity – as documented by Ratey, 2013, who further declared:

Working out before school gives these kids a boost in reading ability and in the rest of their subjects… Physical activity sparks biological changes that encourage brain cells to bind to one another. For the brain to learn, these connections must be made. They reflex the brain’s fundamental ability to adapt to challenges.

TO BE CONTINUED

Please watch for the following documents:

Hormesis

Psychological State That Drives Brain Activation

The Brain’s Environment

REFERENCES

Doidge, N. (2007). The brain that changes itself. The Viking Press.

Gabriel, D. A., Kamen, G., & Frost, G. (2006). Neural adaptations to resistive exercise: mechanisms and recommendations for training practices. Sports medicine (Auckland, N.Z.), 36(2), 133–149. https://doi.org/10.2165/00007256-200636020-00004

Kandel, E.R.; Schwartz, J.H.; Jessell, T.M.; et al. (2013). Principles of neural science. 4^th ed. McGraw Hill.

MGH Institute of Health Professions. (2020). Frederick Robert Carrick, DC, PhD, MS-HPEd. Retrieved from https://www.mghihp.edu/frederick-robert-carrick-dc-phd-ms-hped on August 11, 2020.

Ratey, J.J.; Hagerman, E. (2013). Spark: The revolutionary new science of exercise and the brain. Little Brown and Company. New York.

The Nobel Foundation. The Nobel prize in physiology or medicine: 2000. Retrieved from https://www.nobelprize.org/prizes/medicine/2000/kandel/facts/ on August 11, 2020.

Windhorst U. (2007). Muscle proprioceptive feedback and spinal networks. Brain research bulletin, 73(4-6), 155–202. https://doi.org/10.1016/j.brainresbull.2007.03.010

Woolsey, T.A.; Hanaway, J.; Gado, M.H. (2017). The brain atlas. 4^th ed. Wiley