Flashcards in Final Deck (199)
Name the 6 parts of the CNS that are involved in complex movements
What kind of arrangement does the primary cortex have
What sections of the primary motor cortex is considered premotor
anterior and lateral portions
Where does the premotor area of the primary motor cortex project to?
Primary order motor cortex and basal ganglia
Does the primary motor cortex stimulate movements or contract single muscles?
What part of the brain does the supplemental motor area lie in?
Mainly in longitudinal fissure
What are the 4 functions of the supplemental motor area
positional movements of head and eyes
background for finer motor control of arms/hands
What are the 3 areas the corticospinal tract originates
Primary motor cortex (30%)
Premotor and supplemental areas (30%)
Somatic sensory areas (40%)
What spinal tract makes up the pyramids and medulla
Where do most corticospinal tract fibers run? Do they all run in same area
They cross midline and form the lateral corticospinal tract
No; some fibers stay ipsilateral and form ventral corticospinal tract
True or false the corticospinal tract lies between the caudate and putamen
If all the spinal tracts were cut and the spinal cord was completely separated from brain what would happen?
Flaccidity or "floppy paralysis"
What would happen if spinal cord was cut at mid collicular level? (Decerebrate preparation)
Extensors would be tonically hyperactive "decerebrate rigidity"
What would happen if there was destruction of the cerebral cortex (Decorticate preparation)
Different type of rigidity - "Decorticate spasticity" - tonic excitation from upper area of the reticular formation no longer under inhibitory cortical influence.
What percentage of intracerebral hemorrhages result in decorticate spasticity?
What is decerebration? What does it result in?
Experimental procedure; transection of midbrain at intercollicular level
Loss of sensation; and motor control is profoundly altered
In decerebration does the brain stem control stay intact? Are cortical descending pathways interrupted?
Yes it stays intact
yes they are interrupted
In decerebration what happens to flexion reflexes? What about stretch reflexes?
Flexion reflexes are suppressed
Stretch reflexes are exaggerated
If a patient showed signs of decerebration what would their prognosis be?
What is "spinal shock"
Initial reaction to cord transection
All cord functions including spinal reflexes are depressed (lack of tonic excitation)
At the onset of clockwise rotation (to the right), what would you expect happens in the VIII cranial nerve on the left side?
Decrease in firing rate
After 20 clockwise (to the right) rotations with the eyes closed on a revolving stool, the subject is abruptly stopped, and the eyes are opened.
What is observed?
Lateral nystagmus with the slow component clockwise
When supine, head tilt is best detected by what?
When standing, head tilt is best detected by what?
True or false, signals from neck proprioceptors typically augment signals from the vestibular apparatus as the head and neck are rotated and have similar effects on limb flexion and extension. What would make this statement the opposite of the answer?
Signals from neck proprioceptors would oppose not augment (assist)
In backward sway, what sequence of contraction of muscles to maintain balance would occur?
Tibialis, then quadriceps, then abdominals
In forward sway, what sequence of contraction of muscles to maintain balance would occur?
Gastrocnemius, then hamstrings, then paraspinals
What would happen to a repetitive simple stretch reflex, if when the muscle contracts it destabilizes posture?
it would be inhibited
What would happen to a repetitive simple stretch reflex, if when the muscle contracts it stabilizes posture?
It would be facilitated