Motor Systems (Book 2, Ch 9)
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Final output to muscles is via the spinal motor neurons (the final common
pathway)
Motor neurons receive inputs ('instructions') from many sources, e.g.
Segmental inputs (reflexes)
Descending pathways:
-
Corticospinal (pyramidal) tracts - originate in motor cortex (Area
4). Serve voluntary movements, especially of distal muscles (e,g, fingers).
-
Brainstem ("Extrapyramidal") systems
Function: to provide coordination, and postural support (especially
axial muscles) for other movements.
Numerous pathways, arising from:
-
Tectum (Tectospinal tract)
-
Reticular formation (reticulospinal tract)
-
Vestibular nuclei (vestibulospinal tract)
-
Red nucleus (rubrospinal tract)
Basal ganglia: linked to planning and initiation of movements: complex
feedback control circuits with motor and premotor cortices.
Cerebellum: coordination of movements, especially learned movements;
balance.
Check out the general organisation of the nervous
system.
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