Descending Pathways Flashcards
Where does the anterior corticospinal tract cross?
spinal cord
- to terminate in the anterior gray column of the spinal cord segments in the cervical and upper thoracic regions
From the cortex, the descending fibers converge in the _______ and then pass through the _______ limb of the internal capsule.
corona radiata
posterior limb of IC
At the posterior limb, CST fibers that are closest to the genu are concerned with which portions of the body?
Cervical
At the posterior limb, CST fibers that are located more posteriorly are concerned with which portions of the body?
lower limbs
Part of the midbrain where the CST passes?
Basis pedunculi
At the pons, the CST is broken into many bundles by:
transverse pontocerebellar fibers
In the medulla, the bundles of CST are group together in which portion or aspect of the medulla?
lower anterior border
The fibers of the corticonuclear tract ARISE from neurons in the
primary motor cortex
secondary motor cortex
frontal eye field
Fibers of the frontal eye field are located in which gyrus?
middle frontal gyrus
Fibers from the frontal eye fields influence eye movements indirectly by synapsing on cells in the:
superior colliculi
pretectal nuclei
accessory optic nuclei of the midbrain
Fibers from the frontal eye fields project directly, or by way of another relay in the ___________, to the nuclei of the oculomotor, trochlear, and abducens nerves
pontine reticular formation
Fibers from the facial region of areas 4 and 6 terminate on internuncial neurons adjacent to the motor neurons that innervate the _____________ muscles, either of somatic or branchiomeric origin.
non-extraocular striated skeletal muscles
The part of the hypoglossal nucleus that supplies the __________ muscle receives corticonuclear fibers only from the opposite cerebral hemisphere
genioglossus
Which reticulospinal tract descends bilaterally?
Lateral (medullary) RST
Which reticulospinal tract descends ipsilaterally?
Medial (pontine) RST
RST from which part of the brainstem descend through the anterior white column?
Pons
Which tract facilitates the activity of the flexor muscles?
Rubrospinal tract
Where is red nucleus situated?
Situated in the tegmentum of the midbrain at the level of the superior colliculus
The spinal lemniscus is located in which part of the midbrain?
tegmentum
This tract is believed to be an important indirect pathway by which the cerebral cortex and the cerebellum can influence alpha and gamma motor neuron activity
Rubrospinal tract
The nuclei situated in the pons and medulla oblongata beneath the floor of the fourth ventricle
Vestibular nuclei
The vestibular nuclei is beneath which ventricle?
Fourth ventricle
Axons of the Deiter’s nucleus descend in which part of the spinal cord?
Anterior column
Nucleus involved in movements of the head required for maintaining equilibrium
Medial Vestibular nucleus of Schwalbe
