Motor Disorders, Subcortical and Cortical (Parkinson’s disease, Huntington’s disease, Tourette’s disease)

Cortical Motor Disorders and classifications of Apraxia (dressing, constructional and limb apraxia)

Not thinking about it

Yesterday I was doing pull ups, handstanding, and some balancing on a canoe with no giving a single thought of how I should execute my muscles to move so they would pull me up above the bar. Or how would my wrists, abs and thighs strengthen and balance me while I pushed my feet toward the sky. Honestly, I somewhat rarely give any thoughts to my muscles when I’m doing a workout. What I think about is more around my egoistic nature: do I have enough strength, do I feel lazy, or how should I motivate myself to keep going that one final press.

That said, I believe our brains must be automatically giving the proper line of executable commands for our muscles to do the right thing. Also I believe, if I would interfere with how my brain does that, I think I would not be able to… walk! To command muscles is that complex.

Konstantin Nikkari performing a hand stand.

In a library, an hour before my mid-town exercising next to a busy road of loud cars, and below green parrot-like birds which were competing with the loudness of cars, I was having an interesting read about motor disorders. The more I read about brain functions, and malfunctions the more I seem to get fascinated about it. On my blog here I like to share something I learned about these disorders. They are common motor disorders of which some of them you might have heard.

This summary of motor disorders is read, learned and to some extent copied from the Cognitive Neuroscience, Banich 2018, book and from a really nice index of a Finnish health library called Terveyskirjasto (

Motor disorders

For normal order and function of a movement we need a sound brain and muscle. They work together communicating back and forth. If either of them, or the line of signal between is broken, then the chain of command is malfunctional and motoric movements have disorders. This is the most simple way of putting this!

Let’s split motor disorders into two categories: Subcortical Motor Disorders (called usually Someone’s diseases) and Cortical Motor Disorders (Apraxias). 

Subcortical Motor Disorders

Deep in midbrain and diencephalon we have the cerebellum, the basal ganglia, and the limbic system. Each of them are important for modulating basic movements. They are below the cerebral cortex and that is why they are called subcortical systems. When a disorder is affected by their malfunction it is a Subcortical Motor Disorder. 

Parkinson’s disease

The second most common neurodegenerative disorder, right after Alzheimer’s disease, is Parkinson’s disease. It occurs because the putamen is not receiving enough of the neurotransmitter dopamine. This disease starts usually at the age of 50-70. It is a slowly progressing movement disorder that is accompanied by tremors, general slowing of movement and muscle stiffness.

Huntington’s disease

A dominantly inherited disease of the central nervous system characterised by compulsive jerking and writhing movements, psychiatric symptoms and general boredom. Huntington’s disease is caused by a rare, 1.6 per million change where a dominant gene has been inherited. And when this happens, the Huntington’s disease does always express itselves. The gene damages the striatum.

Tourette’s disease

Two months ago I was listening to a man’s story about how he had had addiction fights against the online game World of Warcraft and numerous different drugs he used. Throughout the video he was doing sniffs and rapid face expressions which he apologised as his tics explaining he had them throughout his life, also before the addiction. It was my first time to learn about such a thing as tic. Now I can say maybe he is having Tourette’s disease, which is a rare disorder that manifests itself in childhood and is characterised in less severe cases by tics and twitching of the face, limbs and other body regions. If this man would have been also making cries, grunts and curses then he would have a severe version of Tourette’s disease. I will link his video below this post.

Cortical Motor Disorders and classifications of Apraxia

On the surface of the brain we have a cortical region for motor control which we use for planning and guiding skilled movement combined with our sensory inputs. Good example of such difficult task would be playing an accordion, where you fingers press buttons, hands open and closes the instrument for the air flow, your ears hear the sound and your fingertips feel the press… in addition to all that, in some part of your brain- sorry for not knowing which part, is calculating the rhythm, planning how to play the next tune and providing the soul to the music you play. I hope you understand we are talking about a really complex line of commands that goes back and forth from the brain. In such cases if you have been a skilled accordionist and suddenly can no longer perform this set of commands needed to produce a melody, you might have apraxia; brain-based difficulty performing meaningful, previously learned movement sequences. This disorder typically results from left inferior parietal lesions or left frontal lesions. 

Apraxias are called by the area of action the damage affects. I will now introduce three apraxia examples.

If the person is not able to open up a jacket so that the arm can be inserted, bent from the elbow to ease the put on the jacket we would call this a Dressing apraxia, a difficulty to manipulate and orientate with cloths together with limbs. Constructional apraxia is inability to copy an arrangement of buckets set by someone else and manipulate your own set of buckets so that it would resemble the example. Both dressing and Constructional apraxias are examples of a difficulty to correctly manipulate items with regard to the spatial relations.

Third apraxia I find very interesting is Limb apraxia. This is a loss of ability to use your limb to manipulate items such as spoons, scissors and hammers. You would also not be able to use keys to open doors or charge your phone by inserting the USB cable into the port. Limb apraxia also affects a person’s ability to pantomime and gesture, like waving hands for goodbye or salute. In pantomime a person affected by this apraxia would use his body part to present the object he is mimicking. For example, if you were asked to show me how you stir sugar with a spoon in your tea cup you would hold an invisible spoon and stir it inside the cup. Limb apraxia patient would extend his finger and stir that inside a cup.

Figure 4.24 from Cognitive Neuroscience, Banich 2018

I have spent some days learning and writing about motor disorders. You and I are having a really complex system inside of our brain and body to operate our movements. So next time we would go and do the simplest planned tasks such as going to the bathroom to brush our teeths, I think we should appreciate our well operating motor disorder.

Here is a rather long but very interesting video of a man letting us into his struggle against online game World of Warcraft and drug addiction. Unfortunately I don’t know his name so I can not tell much more about him other than he supposedly is now working with some Substance Abuse and Mental Health Services Administration. You might be able to find more info of this man by following the link on this video and entering the YouTube site.


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