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MOTOR SYSTEMS
I. TRUE or FALSE. Circle the T or F as appropriate.
T F 1. Clarke's column (the dorsal nucleus of Clarke) receives input from primary
cutaneous, joint and muscle afferents and projects to the cerebellum.
T F 2. Painful pinching of a cat's right hindpaw produces reflex extension of its left
hindpaw.
T F 3. Alpha motorneurons lying nearest the midline of the spinal cord innervate
muscles of the distal extremities.
T F 4. The ventral spinocerebellar tract conveys signals from spinal interneurons to
the cerebellum.
T F 5. When the Ia spindle afferents in a muscle are stimulated by stretch, these
afferents inhibit the antagonist muscle through direct, monosynaptic
inhibitory contacts onto alpha motorneurons.
T F 6. The interposed nucleus of the right cerebellum (i.e., interpositus or globose +
emboliform nuclei) helps to coordinate movements on the right side of the
body by way of the left red nucleus.
T F 7. The anterior (or ventral) corticospinal tract decussates in the medulla and
influences mainly muscles of the distal extremities.
T F 8. The deep cerebellar nucleus most closely linked to the vestibular system is the
dentate nucleus.
T F 9. The axons of cells in the pontine gray convey signals from the neocortex to the
ipsilateral cerebellum through the superior cerebellar peduncle.
T F 10. The subthalamic nucleus is a component of the olfactory system.
T F 11. Hemisection (i.e., transection of one half) of the spinal cord produces
ipsilateral loss of thermal sensation and contralateral spasticity and loss of
position sense.
T F 12. A lesion that impairs a patient's ability to speak is certain to lie above the level
of the brainstem.
T F 13. Dopaminergic innervation of the caudate nucleus comes primarily from the
raphe nuclei.
T F 14. The mediodorsal nucleus of the thalamus projects mainly to the parietal
cortex.
T F 15. The parallel fibers in the molecular layer of the cerebellar cortex are the axons
of cerebellar granule cells.
T F 16. The left cerebral cortex is functionally related primarily to the right cerebellar
hemisphere.
T F 17. The external segment of the globus pallidus projects to ventral posterior
nucleus of the thalamus.
T F 18. The stretch (myotatic) reflex helps the motor system compensate for variable
loads.
T F 19. Increasing activity in the gamma motorneurons (while keeping joint position
constant) can be expected to decrease the firing rate in muscle spindle
afferents.
T F 20. The ventral spinocerebellar tract conveys primarily information about the
status of spinal interneurons to the cerebellum.
T F 21. The vermis is part of the spinocerebellum.
MULTIPLE CHOICE. Circle every correct answer. There may be more than one correct
answer per question.
1. Fibers in the lateral funiculus of the spinal cord include those of the
a.
b.
c.
d.
e.
lateral vestibulospinal tract
dorsal spinocerebellar tract
lateral corticospinal tract
rubrospinal tract
anterior corticospinal tract
2. The myotatic reflex (the stretch or "knee-jerk" reflex)
a. is triggered by mechanical stretch of the Ib fibers of the Golgi Tendon Organ
b. involves monosynaptic connections between primary spindle afferents and
alpha motor neurons
c. is part of a neural control system for managing variable muscle loads
d. results in the contraction of the muscle antagonistic to the one stretched
e. is not apparent in people with longstanding lesions of the long descending motor
pathways (from cortex and brainstem to spinal cord)
3. Axons contributing to descending spinal tracts which influence axial muscles more
than distal ones arise from
a.
b.
c.
d.
e.
Purkinje cells of the cerebellar hemisphere
the red nucleus
the brainstem reticular formation
the internal segment of the globus pallidus
the lateral vestibular nucleus (Deiter's)
4. Purkinje cells of the cerebellar cortex
a.
b.
c.
d.
e.
use GABA as their transmitter
project primarily to the deep cerebellar nuclei
receive inputs from parallel fibers in the molecular layer of the cerebellar cortex
receive climbing fiber inputs from the inferior olive
receive inputs from large numbers of cerebellar granule cells
5. The cerebellar hemisphere is functionally connected
a.
b.
c.
d.
more to the cerebral cortex on the same side than to that on the opposite side
more to the dentate nucleus than to the fastigial nucleus
more to the vestibular nuclei than to the pontine gray
more directly to the primary motor cortex than to the prefrontal association
cortex
e. more to the spinal cord on the same side than to that on the opposite side
6. The thalamic nuclei that are the primary relay of signals from the basal ganglia to the
cortex
a. receive their main basal-ganglia input from the caudate and putamen
b. receive their main basal-ganglia input from the subthalamic nucleus and
external segment of the globus pallidus
c. receive their main basal-ganglia input from the internal segment of the globus
pallidus and pars reticulata of the substantia nigra
d. receive their main basal-ganglia input from the ventral tegmental area and pars
compacta of the substantia nigra
e. project most heavily to the parts of the frontal lobe anterior to the primary motor
and premotor cortex
7. Which of the following are "input nuclei" of the basal ganglia (that is, they are the
main targets within the basal ganglia of inputs from structures outside the basal
ganglia)?
a.
b.
c.
d.
e.
external segment of the globus pallidus
internal segment of the globus pallidus
VA-VL nuclei of the thalamus
putamen
nucleus accumbens (ventral striatum)
8. The cerebellum
a. influences the primary motor cortex by virtue of a projection to the VA-VL
nuclei of the thalamus
b. receives proprioceptive information from the spinocerebellar tracts
c. is a critical element in the neural mechanism of conscious proprioception
d. receives climbing fiber projections from the pontine gray
e. can influence limb musculature by virtue of its projections to the red nucleus
9. The "ventromedial brainstem pathways" of Kuypers and Lawrence
a.
b.
c.
d.
e.
include the rubrospinal tract
include the reticulospinal tract
include the medial vestibulospinal tract
are involved in the control of distal limb musculature
course primarily in the dorsal funiculus of the spinal white matter
MOTOR SYSTEMS
I. True or False
1.
2.
3.
4.
5.
6.
7.
T
T
F
T
F
T
F
II. Multiple Choice
8.
9.
10.
11.
12.
13.
14.
F
F
F
F
F
F
F
15.
16.
17.
18.
19.
20.
21.
T
T
F
T
F
T
T
1.
2.
3.
4.
5.
b,c,d
b,c
c,e
a,b,c,d,e
b,d,e
6. c,e
7. d,e
8. a,b,e
9. b,c