(28) NEUROPLASTICITY & MY PD

RECAP In Post 27, I shared some ideas around my freezing and subsequent use of trigger words to initiate internal cueing to assist faltering movement. Many of us with Parkinson's Disease (PD) are reliant on such a strategy to attempt to kickstart dormant motor learning in order to make our limbs move. One example of re-initiating motor learning is overcoming my difficulty - as a PD person - of moving from a seated to a standing position, as illustrated below.

In Post 27, I also focussed on strategies for the re-execution of movement. What is interesting is that while this cueing strategy is supported by the combined effort of a body's muscular, skeletal and nervous systems, I've ignored the fact that the brain has an unfathomable capacity to adapt under extreme circumstances. Let's briefly explore neuroplasticity and my PD.

 

PD: I'm the dope with depleted dopamine

I have PD. I have been told this condition exists because of dwindling levels of dopamine, a complex chemical in my brain. This 'dwindling' has probably occurred over an extended period of time. If that's so, then it could have been triggered by a traumatic brain injury when I was a child (1956) and other specific traumas I can pinpoint during my adult life (1999, 2007, 2012).

From what I've read, dopamine is manufactured in my brain and functions as a neurotransmitter to send messages across my nervous system to deal mostly with movement. For a brief, scientific explanation of dopamine, see the 2 minute video. Besides being a chemical messenger, dopamine is a hormone: it plays a role in mediating rewards in my brain, both as the "excitatory" hormone responsible for my feel-good times, as well as the "inhibitory" type. But it also plays a role in regulating chronic pain, amongst a host of other functions. So, dopamine is no dope!    

What I've learnt about my PD since I retired end-2017 is that, firstly, I have a movement disorder that plays havoc with my muscle confidence. This disorder, coupled with my tremors, instills the constant belief that I need to rest. As a result, I rest more than is required leaving my muscles over-rested and underused. So, I am unable to do simple tasks, although my muscular, skeletal and nervous systems are functional. 

Secondly, being over-rested means my muscle memory converts to muscle-forgetory (see Posts 6, 15 & 16)  making me believe I am incapable of moving "normally". This appears to be a powerful function of my brain, namely, to adjust the body's functions to suit what is the strongest. When my right side started weakening due to the impact of PD my left-hand automatically took over (see Post 8 regarding dexterity) and dominated certain right-hand functions. 

And thirdly, because my nervous system controls my sense of temperature, as a parkinsed person, I am now more sensitive to temperature shifts, both hot and cold. In Post 9 I referred to "trevers" i.e., tremors + shivers, when it gets cold. 

So if my muscular, skeletal and nervous systems are okay, then what is the problem? Probably the decreasing amount of dopamine in my Substantia Nigra (see 2 minute video). Some of this is speculation on my part, so in keeping with my speculative stance I will look at the positives such as my shifting dexterity and cueing to re-initiate my motor learning. Besides the three systems just mentioned, dear reader, let's not forget the brain and its plasticity. 

What is neuroplasticity?

There was a time when scientists believed that the creation of new neurons (i.e. neurogenesis) stopped shortly after birth but that has been proved to be incorrect. The notion of neuroplasticity - also called brain plasticity - is based on evidence first recorded by a Polish neurophysiologist, Jerzy Konorsky, in 1948. He wondered if it was possible to alter existing neural connections in the brain through conditioning (naturally, Skinner and Pavlov were also in this think tank). Later it emerged that new experiences linked to change could influence the brain to reorganise most neural pathways and even generate new ones throughout one's life. Neuroplasticity is a combination of the essence of the nervous system (i.e. neurons) and the brain's capacity to be remoulded (i.e. plasticity) in the face of an individual's challenges. 

One example of 'remoulding' is the ability of a musician such as Ray Charles to excel at tasks generally achievable by a sighted person. He was not born blind and his musical ability as a singer and pianist was superior to that of many of his sighted contemporaries. It could be said that he was able "to perform non-visual tasks better than those with sight". I had the privilege of attending one of his live performances in the nineties and his musical performance together with his piano stool antics made it unforgettable! 

Another example is the phenomenon of phantom limbs where an amputated limb still appears to exist in the mind of the amputee. This supports speculation that every person's brain contains the equivalent of a detailed diagram of all bodily functions and accompanying support systems to sustain the idea of neuroplasticity. Below is an illustration of brain plasticity. 

How experience changes brain plasticity

Regarding the principle of plasticity, it is possible that my advanced internal cueing leans towards functional plasticity. According to Psychology Today plasticity makes it "possible to change dysfunctional patterns of thinking and behaving and to develop new mindsets, new memories, new skills, and new abilities". 

A brief deviation: my advanced cueing for dressing, walking and climbing stairs would be similar to creating a learning strategy called a mnemonic. This allows one to remember a series of words or names in a specific order. For instance, when trying to remember the colours of the rainbow in order, I remember this mnemonic: Richard Of York Goes Battling In Vain. Each first letter is the first letter of word representing a colour, namely red, orange, yellow, green, blue, indigo, violet. The silly sentence about Richard is a primary trigger that takes me to the source, the actual colours. 

This seemingly long process is, in my experience, how successful remembering can occur. So, my shift from saying "toe-toe" to counting from 1-6 when climbing six stairs is my way of creating a sense of continuity (from a green light to amber - see Post 27) in my stilted movement. Maybe, the fact that it works is my brain telling me it has accepted an amended cue and indicating that a form of learning has taken place. Hmm...evidence of plasticity?   

This perspective of neuroplasticity is an enlightening one for me as a parkinsed person. I have scratched the surface of this phenomenon to provide food for thought, dear reader. There is also recent research on exercising and neuroplasticity that I have included below to further whet your appetite. 

Neuroplasticity and exercise: more food for thought...

Research published in 2019 found that the impact of aerobic exercise resulted in positive change in the brain plasticity of subjects with PD (see EXPANd trial article no. 2 in Resources below). The article focuses on two groups, (1) a HiBalance and (2) a HiCommunication group. Their broad focus area was on exercise as a form of non-medical intervention for those with PD, particularly in the light of the unpredictable nature of current pharmaceutical "remedies". 

Another strand of research also published in 2019 is on healthy subjects without PD and the impact of extreme aerobic exercise on their brain plasticity (see "Exercise-Induced Neuroplasticity..." article no. 1 below). It focuses on exercising among healthy individuals and indicates that "fit individuals show greater neuroplasticity induction than unfit individuals". 

Happy Holidays, dear reader, and thank you for visiting this blog. Till we connect in 2022.

Resources

Neuroscience: click on desired link & when site opens scroll down for short video.

1. Know your brain: Substantia Nigra
2. 2 minute video: Dopamine
3. 2 minute video: Parkinson's Disease
4. 2 minute video: Huntington's Disease
5. 2 minute video: Caffeine (vs adenosine)  
6. 2 minute video: Reward system

 Articles

1. This journal article focuses on the effect of exercise on healthy individuals without PD. If you're bored, then only read the Abstract (at the beginning) and the Limitations and Conclusion paragraphs (at the end). "Exercise-induced neuroplasticity: a Mechanistic Model and Prospects for Promoting Plasticity." by El-Sayes et.al. (2019). Available as a PDF.
2. This journal article focuses on individuals with PD: "The EXPANd trial: effects of exercise and exploring neuroplastic changes in people with Parkinson's disease: a study protocol for a double- blinded randomized controlled trial. By Franzén, et.al." (2019). Available as a PDF. 
3. How our brain adapts to impairment: "Loss of Sight and Enhanced Hearing: a Neural Picture." 
4. A blog site for PD people like me: "Fighting Parkinson's Drug Free."
5. A useful easy read on brain plasticity in a South African publication "Psychology Today."  
6. What is neuroplasticity? Positive Psychology
7. This chapter: Neuroplasticity after traumatic Brain Injury by Su, Veeravagu & Grant, focuses on traumatic brain injury and neuroplasticity. If you're bored then just read the introductory paragraphs, the section on Neuroplasticity and the Conclusion.