Pathways

Question 1

Pathways

Answer 1

There are MANY complex motor pathways. Two major ones are…

Cortico-Spinal (“Pyramidal”) Tracts

Ventro-Medial Tracts

• These pathways are primarily Ipsi-lateral, (though some collaterals crossover in Brain Stem)
• Primarily controls posture, movement of neck, shoulders & trunk, esp in co-ord with sensory activity
  (e. g. head/eye movement) & gross body movement (walking) – Note all involve both sides at once

Question 2

Cortico-Spinal (“Pyramidal”) Tracts

Answer 2

mainly to Contra-Lateral Periphery, crossover at Pyramids of Medulla

• Large Pyramid Cells
• Fast, myelinated tracts,

Question 3

Large Pyramid Cells

Answer 3

from Motor Cortex, synapse in Spinal Cord (onto Inter-Neurons or Motor Neurons)

• Some synapse first at Red Nucleus (e.g. integrate w/Vestibular & Cerebellar info) then most to Cord

Question 4

Red Nucleus

Answer 4

(e.g. integrate w/Vestibular & Cerebellar info)

Question 5

Fast, myelinated tracts,

Answer 5

esp. for precise control of peripheral movements (e.g. hands, fingers, limbs, + face)

Question 6

Ventro-Medial Tracts

Answer 6

Mainly for Bi-Lateral Midline control

• Multiple sub-paths,
• Many make multiple connections in Tectum, Vestibular Nucleus, Reticular Formation, then to Cord

Question 7

Bi-Lateral Midline control

Answer 7

(both sides of central body & co-ord’d limbs)

Question 8

Multiple sub-paths

Answer 8

originating from sub-cortex, most synapse in Spinal Cord, esp on Inter-Neurons

—Many make multiple connections in Tectum, Vestibular Nucleus, Reticular Formation, then to Cord