VII- Upper Motor Neurons Flashcards
premotor cortices
lateral premotor cortex + supplementary motor cortex
planning and sequencing prior to move
parts of dorsolateral
- lateral corticospinal
- rubrospinal
mirror neurons function
in primates and humans
active when performing an action and observing another indiv doing the same thing
-NOT respond when context is unfamiliar
major movements of descending motor
dorsolateral = flexors of extreminites
ventromedial = extensors to proximal muscles and torso
primary motor cortex
@precentral gyrus
execution of contralateral voluntary movement since decussate (small proportion don’t cross)
-precise control and reg muscle contraction force
pyramidal cells in primary motor cortex routes
- most will activate interneurons in spinal intermediate zone > alpha neurons
- some will directly monosynaptic activate alpha neurons
inter hemispheric connection function
to coordinate posture by axial muscles and proximal extremities
-no connections in distal regions for greater independence
betz cells
in primary motor cortex
-small proportion but large axons so fastest signaling
ventromedial tracts
- reticulospinal
- vestibulospinal
corticobulbar tract
control muscles of face, head, neck
corticospinal tract
skilled voluntary movement
-direct pathway either to interneurons or distal extremity alpha neurons
ventral corticospinal tract
axons descend uncrossed and terminate bilaterally
-control axial and proximal muscles for postural control of neck, shoulders, upper limb
rubrospinal tract
for proximal flexor muscles + assist well learned rote movements
-from red nucleus > decussate in midbrain > interneurons for alpha
internal capsule orientation
- face (anterior)
- arm
- trunk
- leg (posterior)
of posterior limb
blood supply to internal capsule
lenticulostriate arteries from middle cerebral
-susceptible to stroke