week 8

Motor System and Movement Control

I’ve always been fascinated with Stephen Hawking. Not because everyone else was (especially in the nerdy school lunch talks), but because I had a personal connection. My dad had always encouraged me on my fascination for the stars and the movement of planets. I had read the books ‘A Brief History of Time’ and ‘The Universe in a Nutshell’ in my early teens and spun my childhood imagination to the galaxies and science-fiction. But most importantly I had a godfather, Jorma Louko, who studied under Stephen Hawking at the University of Cambridge and went on to the University of Nottingham to do research in the interplay of gravity and the quantum. Even with these great role models I somehow never managed myself into pure mathematics. Just didn’t have the aptitude for it, instead choosing to roam around in the warm fuzzy arts and engineering field.

Now you might be asking what has this got to do with week 8 and the human motor system, and movement control. Well yes, the first paragraph almost nothing, except with Stephen Hawking everything… he had a rare early-onset slow-progressing form of motor neurone disease (also known as amyotrophic lateral sclerosis, “ALS“, or Lou Gehrig’s disease), that gradually paralysed him over the decades. This disease was also referenced in our chapter readings Box 13.1 “ALS: Glutamate, Genes, and Gehrig” depicting it as a “particularly cruel disease that was first described in 1869 by the French neurologist Jean-Martin Charcot” that show as muscle weakness and atrophy and progresses to movement loose and eventually to death by failure of the respiratory muscles. The disease has no effect on sensations, intellect, or cognitive function making the victim watch their own bodies deteriorate with no way of affecting it. ALS degeneration affects large alpha motor neurons leaving other neurons in the CNS intact. The causes of the disease are unknown, but it is believed to have something to do with excitotoxicity (“overstimulation by the excitatory neurotransmitter glutamate and closely related amino acids can cause the death of otherwise normal neurons” – Chapter 6). Interestingly only 10% of ALS cases are inherited the rest seem to be caused by environmental causes, such as, cycad nuts, which contain an excitotoxic amino acid. Looking at inherited ALS recent research has identified mutations of about 16 genes. And there is still so much to be understood and treatments are still in the distant future, with “neuronal stem cells to replace lost neurons and glia, and genetics-based strategies to suppress the effects of mutations”.

A science-fiction leap forward would be if technology could replace our bodies as in the cult movies chappie, Robocop, ghost in the shell, etc. This would allow for ALS patients to move from their broken bodies into completely new ones. A far in the future possibility, but interesting to speculate since we already have working concepts coming out in cybernetics. An example is MIT designer Hugh Herr who builds “prosthetic knees, legs and ankles that fuse biomechanics with microprocessors to restore (and perhaps enhance) normal gait, balance and speed”. He’s captivating ted talk can be viewed here.