Wikipedia Extrapyramidal Revision

Cross references:  Extrapyramidal System   

I originally considered the extrapyramidal system while trying to determine whether human fast and slow twitch muscles are innervated by nerves with separate, discrete origins as is the case with  Amphioxus Muscles .  I got side-tracked by the Wikipedia article which claimed that "... the extrapyramidal system appears to have emerged relatively recently  ...".  Since my understanding of human behavior includes the view that the extrapyramidal system is an integral part of our ancient subcortical brains, I felt that I needed to resolve its relative age before going on with the fast-twitch vs. slow-twitch issue.    


08-22-13   

This is an important day in my life.  I've managed to edit a Wikipedia page: 
    Extrapyramidal system - Wikipedia, the free encyclopedia     
   
http://en.wikipedia.org/wiki/Extrapyramidal_system
This is significant for two reasons: 
    1.  It moves our understanding of ourselves one step forward. 
    2.  References [1] and [2] are links to two of my webpages.  Hopefully this will drive traffic to them and I'll become rich and famous. 


This is the Wikipedia entry before I edited it.  I have indicated where the section I revised began and ended.  Note that the footnotes no longer lead to the original references.  They point to the new references.   

Extrapyramidal system (Wiki) 
    "In human anatomy , the extrapyramidal system is a neural network that is part of the motor system that causes involuntary reflexes and movement, and modulation of movement (i.e. coordination). The system is called "extrapyramidal" to distinguish it from the tracts of the motor cortex that reach their targets by traveling through the " pyramids " of the medulla . The pyramidal pathways ( corticospinal and some corticobulbar tracts) may directly innervate motor neurons of the spinal cord or brainstem ( anterior (ventral) horn cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers around the modulation and regulation (indirect control) of anterior (ventral) horn cells.

Extrapyramidal tracts are chiefly found in the reticular formation of the pons and medulla, and target neurons in the spinal cord involved in reflexes, locomotion, complex movements, and postural control. These tracts are in turn modulated by various parts of the central nervous system, including the nigrostriatal pathway , the basal ganglia , the cerebellum , the vestibular nuclei , and different sensory areas of the cerebral cortex . All of these regulatory components can be considered part of the extrapyramidal system, in that they modulate motor activity without directly innervating motor neurons.   

The section I revised began here:   

Evolutionary, the extrapyramidal system appears to have emerged relatively recently and is most developed in species such as primates which require fine motor control. [1] For example, if the animal is to contract one digit independently from another, first the pyramidal system sends a signal for all digits on the specified hand to contract and only afterwards does the extrapyramidal tract send an addendum signal which causes all but one digit to ignore the initial pyramidal signal, hence causing only one digit to contract. Such an organization, although indirect, reflects an evolutionary tendency to add new layers of refinement rather than risk drastically altering vital basic systems. 

The section I revised ended here:   

The extrapyramidal tracts include parts of the following: [2]
My comment:   
           
    The original reference, " [1] " led to: 
Robert Sapolsky (April 30, 2010). Limbic System (Human Behavioral Biology). Stanford University.
  which is a YouTube video of a lecture given to a class at Stanford University. 
    14. Limbic System - YouTube 
    http://www.youtube.com/watch?v=CAOnSbDSaOw    
The segment quoted in Extrapyramidal System   begins at 38+ minutes.  Dr. Sapolsky is lecturing very loosely to a group of students who seem to be just beginning their study of neuroanatomy, and he provides no references for his statements.  His statement that "Evolutionary, the extrapyramidal system appears to have emerged relatively recently ..." is silly.  The vestibulospinal tract , the tectospinal tract and the reticulospinal tract are present in pre-cortical animals, and all are part of the  Extrapyramidal System .

    Since the statement "Evolutionary, the extrapyramidal system appears to have emerged relatively recently ..."  is clearly untrue, and I sent a revision to Wikipedia. 


This is the Wikipedia entry after I edited it.   

Extrapyramidal system (Wiki) 
    "In human anatomy , the extrapyramidal system is a neural network that is part of the motor system that causes involuntary reflexes and movement, and modulation of movement (i.e. coordination). The system is called "extrapyramidal" to distinguish it from the tracts of the motor cortex that reach their targets by traveling through the " pyramids " of the medulla . The pyramidal pathways ( corticospinal and some corticobulbar tracts) may directly innervate motor neurons of the spinal cord or brainstem ( anterior (ventral) horn cells or certain cranial nerve nuclei), whereas the extrapyramidal system centers around the modulation and regulation (indirect control) of anterior (ventral) horn cells.

Extrapyramidal tracts are chiefly found in the reticular formation of the pons and medulla, and target neurons in the spinal cord involved in reflexes, locomotion, complex movements, and postural control. These tracts are in turn modulated by various parts of the central nervous system, including the nigrostriatal pathway , the basal ganglia , the cerebellum , the vestibular nuclei , and different sensory areas of the cerebral cortex . All of these regulatory components can be considered part of the extrapyramidal system, in that they modulate motor activity without directly innervating motor neurons.   

My revision begins here:   

The extrapyramidal system is very old and three of the four tracts of the human extrapyramidal system are clearly present in salamanders.[1][2]

My revision ends here:   

The extrapyramidal tracts include parts of the following:[3]

References

  1. ^ "Brain of the Tiger Salamander" <https://sites.google.com/site/brainofthetigersalamander/>
  2. ^ "Extrapyramidal System - Children of the Amphioxus" https://sites.google.com/site/childrenoftheamphioxus/table-of-contents/extrapyramidal-system
  3. ^ http://www.amazon.com/BRS-Physiology-Board-Review-Series/dp/0781798760/













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