motor control part 1 Flashcards
greater than 1/2 of the primary motor cortex controls what?
hands and speech
what area is anterior to the lateral portions of primary motor cortex below supplemental area?
premotor area
the premotor area projects to?
1 degree motor cortex and basal ganglia
what area is superior to premotor area lying mainly in the longitudinal fissure?
supplemental motor area
what movements do the premotor and supplemental motor areas provide?
attitudinal movements
fixation movements
positional movements of head and eyes
background for finer control of arms/hands
what percentage of the corticospinal tract originates in the primary motor cortex?
30%
what percentage of the corticospinal tract originates in the premotor and supplemental areas?
30%
what percentage of the corticospinal tract originates in the somatic sensory areas?
40%
where does the corticospinal tract descend?
via the posterior limb of the internal capsule (btw caudate and putamen)
what does the corticospinal tract form?
pyramids of the medulla
when corticospinal tract fibers cross midline they form?
lateral corticospinal tract
when corticospinal fibers stay ipsilateral they form?
ventral corticospinal tract
when all tracts are cut and the cord is completely isolated from the brain its called? Low
spinal preparation
flaccidity!
when you have a transection at the mid collicular level mid brainstem its called?
decerebrate preparation
rigidity!
destruction of the cerebral cortex/ high brain stem is called?
decorticate preparation
different type of rigidity- spasticity
which brainstem area that receives stimulation from the vestibular nuclei and transmits excitatory signals to stimulate the axial trunk and extensor muscles that support the body against gravity?
pontine reticular nuclei
which brainstem area that receives strong input from the cortex, red nucleus, and other motor pathways and transmits inhibitory signals to the same antigravity muscles via the medullary (lateral) reticulospinal tract
medullary reticular nuclei
with regard to postural control, if DESCENDING cortical signals are blocked, what is the expected result?
increased extensor tone, flexors repressed- decerebrate rigidity
what is the function of a dynamic signal from pyramidal cells to alpha motor neurons?
initiation of muscle contraction