1. After a brain stem stroke, a person experiences vertigo. Which of the listed arteries likely produced this neurological sign?

A. Superior cerebellar
B. Posterior inferior cerebellar
C. Vertebral
D. Posterior spinal

Comment: The posterior spinal artery supplies the dorsolateral medulla, but caudal to the vestibular nuclei. The anterior inferior cerebellar artery supplies more rostral portions of the vestibular complex.

2. The ascending vestibular pathway projects to the _______ nucleus of the thalamus, where __________ information is integrated with vestibular sensory messages for perception.

A. ventral posterior; proprioceptive
B. medial geniculate; auditory
C. medial dorsal; cognitive
D. ventral posterior; visceral sensory

3. The vestibulospinal tracts are part of which of the following descending systems?

A. Lateral
B. Medial
C. Ventral
D. Lateral and medial

Comment: Despite its name, the lateral vestibulospinal tract is a medial pathway.

4. Ocular depression is produced by contraction of which of the following extraocular muscles?

A. Inferior rectus
B. Inferior rectus and medial rectus
C. Inferior rectus and inferior oblique
D. Inferior rectus and superior oblique

5. A person has a lesion that damaged the oculomotor nerve. Which of the following best describes the position of the affected eye in this person?

A. Elevated and adducted
B. Elevated and abducted
C. Depressed and abducted
D. Depressed and adducted

Comment: Eye position after third nerve lesion is considered “down and out.”

6. Palsy of the fourth nerve does not produce _________.

A. horizontal diplopia
B. torsional diplopia
C. a head tilt away from the affected eye to compensate for weakened ocular intorsion
D. vertical diplopia that becomes worse when looking toward the tip of the nose

Comment: The contribution of the superior oblique muscle, which is innervated by the trochlear nucleus, to downward gaze is greater when looking at the nose, hence greater vertical diplopia. Intorsion—the other mechanical action of the superior oblique muscle—is weakened, hence double vision when you tilt your head sideways, termed torsional diplopia. This is often compensated by tilting the head in the other direction. Finally, horizontal diplopia is produced by a palsy involving control of the lateral or medial rectus muscles.

7. Movement of the two eyes during horizontal saccadic eye movements are coordinated by which of the following brain stem regions?

A. The cerebellum
B. The interstitial nucleus of the MLF and the oculomotor nucleus
C. The paramedian pontine reticular formation and the abducens nucleus
D. The superior colliculus and oculomotor nuclei

Comment: The vertical gaze center is the interstitial nucleus of the MLF; the paramedial pontine reticular formation is the horizontal gaze center and acts on the abducens nucleus.

8. What pathway is important for transmitting vestibular information from the vestibular nuclei to the oculomotor nucleus?

A. Medial lemniscus
B. Dorsal longitudinal fasciculus
C. Medial longitudinal fasciculus
D. Solitary tract

9. Horizontal saccades are to smooth pursuit eye movements as

A. the paramedial pontine reticular formation is to the cerebellum.
B. interstitial nucleus of the MLF is to the superior colliculus.
C. vestibular nuclei are to the cerebellum.
D. prepositus nucleus is to the superior colliculus.

10. On looking to the right, a person experiences diplopia. The right eye is normally abducted, but the left eye does not adduct. Vergence is normal. Lesion of which of the following structures likely produces this sign?

A. Right abducens nucleus
B. Left abducens nucleus
C. Right MLF
D. Left MLF

Comment: The left abducens nucleus is spared, or else the left eye would not be abducted. The left medial rectus muscle is not paralyzed because vergence is normal.