Cross references: Muscle Innervation Motor Neuron Evolution Motor Programs
The PDF cited below is 37 pages long and discusses the motoneurons of 8 different animals. Fast vs. Slow Twitch Muscles Tonic Inhibition Behavioral Disinhibition Somatic Nervous System Amphioxus Amphioxus Motor Nerves Amphioxus Fast-Slow Twitch Dorsal Motor Neurons Ventral Motor Neurons Amphioxus Locomotion Lamprey Lamprey Motor Nerves Lamprey Muscles Lamprey Fast-Slow Twitch Sharks & Rays Shark Muscles Red Nucleus Teleosts Teleost Muscles Amphibians Amphibian Muscles Mammalian Muscles Perinatal Behavior Motor Programs A review of the organization and evolution of
motoneurons http://deepblue.lib.umich.edu/bitstream/handle/2027.42/26658/0000202.pdf?sequence=1 Full length PDF available online for free.
Motor Neuron Evolution Amphioxus Muscles Amphioxus Motor Nerves Lamprey Muscles Lamprey Fast-Slow TwitchTeleost Muscles Amphibian Muscles Mammalian Muscles Somatic Nervous System
The Local Circuit Neurons:
The most explicit reference I've found so far for the preceding blog entry is in: Neuroscience, third edition, page 371
ed. Dale Purves, et al.
Sinauer Associates, Publishers
"The neural circuits responsible for the control
of movement can be divided into four distinct but highly interactive
subsystems, each of which makes a unique contribution to motor control.
The first of these subsystems is the local circuitry within the gray
matter of the spinal cord and the analogous circuitry in the brain
stem. The relevant cells include the lower motor neurons (which send
their axons out of the brainstem and spinal cord to innervate the
skeletal muscles of the head and body, respectively) and the local
circuit neurons (which are the major source of synaptic input to the
lower motor neurons)."
07-15-13 I spent some time "reading about the innervation of motor neurons", not in our subcortical ancestors, but in we humans. Paraphrasing Medial Motor Column , it turns out that the rubrospinal tract, the vestibulospinal tract, the tectospinal tract and the reticulospinal tract influence the output from the Alpha motor neurons , not by providing input to the Alpha motor neurons directly, but by providing input to the very numerous Interneurons which then influence the output from the Alpha motor neurons .
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