494 - 868 IV

Question 1

1. Neurologic examination revealed:
   -miosis, ptosis, hemianhydrosis, left side
   -laryngeal and palatal paralysis, left side
   —facial anesthesia, left side
   -loss of pain and temperature sensation
   from the trunk and extremities, right side
   The lesion site responsible is in the
   (A) caudal medulla, ventral median zone,
   right side
   (B) rostral medulla, lateral zone, left side
   (C) rostral pontine base, left side
   (D) caudal pontine tegmentum, lateral zone,
   right side
   (E) rostral pontine tegmentum, dorsal median
   zone, left side

Answer 1

B. The lesion is a classic Wallenberg’s syndrome (PICA syndrome) of the lateral medullary
zone. Interruption of the descending sympathetic tract produces ipsilateral Horner’s syndrome.
Involvement of the nucleus ambiguus or its exiting intra-axial fibers accounts for lower motor
neuron (LMN) paralysis of the larynx and soft palate. The ipsilateral facial anesthesia is due to
interruption of the spinal trigeminal tract; the contralateral loss of pain and temperature sensa-tion from the trunk and extremities is due to transection of the spinothalamic tracts. The combi-nation of ipsilateral and contralateral sensory loss is called alternating hemianesthesia.
Singultus (hiccup) is frequently seen in this syndrome and is thought to result from irritation of
the reticulophrenic pathway.

Question 2

2. Neurologic examination revealed:
   —severe ptosis, eye “looks down and out,”
   right side
   -fixed dilated pupil, right side
   —spastic hemiparesis, left side
   -lower facial weakness, left side
   The lesion site responsible is in the
   (A) caudal pontine tegmentum, dorsal median
   zone, left side
   (B) rostral pontine tegmentum, dorsal lateral
   zone, right side
   (C) pontine isthmus, dorsal lateral tegmen-tum, left side
   (D) rostral midbrain, medial basis pedunculi,
   right side
   (E) rostral midbrain, medial tegmentum, left
   side

Answer 2

D. This constellation of deficits constitutes Weber’s syndrome, which affects the basis pedun-culi and the exiting intra-axial oculomotor fibers. Severe ptosis (compare mild ptosis of Horner’s
syndrome), the abducted and depressed eyeball, and the internal ophthalmoplegia (fixed dilated
pupil) are third nerve signs. The contralateral hemiparesis results from interruption of the corti-cospinal tracts; lower facial weakness is due to interruption of the corticobulbar tracts. The com-bination of ipsilateral and contralateral motor deficits is called alternating hemiplegia. In cases
of sensory or motor long tract involvement, the involved cranial nerve indicates the rostrocaudal
site of the lesion; the cranial nerve signs are ipsilateral and lateralize the lesion (the trochlear
nerve is the exception).

Question 3

3. Neurologic examination revealed:
   -sixth nerve palsy, right side
   -facial weakness, left side
   -hemiparesis, left side
   -limb and gait dystaxia, right side
   The lesion site responsible is in the
   (A) caudal pontine tegmentum, lateral zone,
   right side
   (B) caudal pontine tegmentum, dorsal median
   zone, left side
   (C) caudal medulla, ventral median zone,
   right side
   (D) rostral pontine tegmentum, lateral zone,
   left side
   (E) caudal pontine base, median zone, right
   side

Answer 3

E. These signs point to the base of the pons (medial inferior pontine syndrome) on the right
side and include involvement of the exiting intra-axial abducent fibers that pass through the
uncrossed corticospinal fibers; this results in an ipsilateral rectus paralysis [lower motor neuron
(LMN) lesion] and contralateral hemiparesis. Contralateral facial weakness results from damage
to the corticobulbar fibers prior to their decussation. Involvement of the transverse pontine fibers
destined for the middle cerebellar peduncle results in cerebellar signs. Again, the involved cra-nial nerve and pyramidal tract indicate where the lesion must be to account for the deficits. An
ipsilateral sixth nerve paralysis and crossed hemiplegia is called the Millard-Gubler syndrome

Question 4

4. Neurologic examination revealed:
   -paralysis of upward and downward gaze
   —absence of convergence
   —absence of pupillary reaction to light
   The lesion site responsible is the
   (A) rostral midbrain tectum
   (B) caudal midbrain tectum
   (C) rostral pontine tegmentum
   (D) caudal pontine tegmentum
   (E) caudal midbrain tegmentum

Answer 4

A. These deficits indicate Parinaud’s syndrome, dorsal midbrain syndrome. This condition fre-quently is the result of a pinealoma, which compresses the superior colliculus and the underlying
accessory oculomotor nuclei that are responsible for upward and downward vertical conjugate
gaze. Patients usually have pupillary disturbances and absence of convergence

Question 5

5. Neurologic examination revealed:
   -bilateral medial rectus paresis on at-tempted lateral gaze
   -monocular horizontal nystagmus in the
   abducting eye
   -unimpaired convergence
   The lesion site responsible is in the
   (A) midpontine tegmentum, dorsomedial
   zones, bilateral
   (B) rostral midbrain tectum
   (C) caudal midbrain tectum
   (D) caudal pontine base
   (E) rostral midbrain, bases pedunculorum

Answer 5

A. This lesion site indicates medial longitudinal fasciculus (MLF) syndrome, internuclear oph-thalmoplegia. The lesion is located in the dorsomedial tegmentum and is found between the
abducent nucleus and the oculomotor nucleus.

Question 6

6. Neurologic examination revealed:
   -ptosis, miosis, and hemianhydrosis, left
   side
   —loss of vibration sensation in the right leg
   —loss of pain and temperature sensation
   from the trunk, extremities, and face,
   right side
   —severe dystaxia and intention tremor, left
   arm
   The lesion site responsible is in the
   (A) rostral midbrain tegmentum, right side
   (B) rostral pontine tegmentum, dorsal medial
   zone, left side
   (C) pontine isthmus, dorsal lateral zone, left
   side
   (D) rostral medulla, lateral zone, left side
   (E) caudal medulla, lateral zone, right side

Answer 6

C. These deficits correspond to a lesion in the dorsolateral zone of the pontine isthmus, lateral
superior pontine syndrome. Interruption of the descending sympathetic pathway to the cil-iospinal center of Budge (T1-T2) results in Horner’s syndrome (always ipsilateral). Involvement
of the lateral aspect (includes the leg fibers) of the medial lemniscus results in a loss of vibration
sensation and other dorsal column modalities. Damage to the trigeminothalamic and spinothala-mic tracts at this level results in contralateral hemianesthesia of the face and body. Infarction of
the superior cerebellar peduncle leads to severe cerebellar dystaxia on the same side.

Question 7

7. Neurologic examination revealed:
   -weakness of the pterygoid and masseter
   muscles, left side
   -corneal reflex absent on left side
   -left facial hemianesthesia
   The lesion site responsible is in the
   (A) midpontine tegmentum, lateral zone, left
   side
   (B) midpontine base, medial zone, left side
   (C) caudal pontine tegmentum, lateral zone,
   left side
   (D) caudal pontine tegmentum, dorsal medial
   zone, left side
   (E) foramen ovale, left side

Answer 7

A. These signs indicate lateral midpontine syndrome. This lesion involves the motor and prin-cipal trigeminal nuclei and the intra-axial root fibers of the trigeminal nerve as it passes through
the base of the pons. AH signs are ipsilateral and refer to CN V. The afferent limb of the corneal
reflex has been interrupted. This syndrome results from occlusion of the trigeminal artery, a
short circumferential branch of the basilar artery.

Question 8

8. Neurologic examination revealed:
   -loss of the stapedial reflex
   -loss of the corneal reflex
   -inability to purse the hps
   —loss of taste sensation on the apex of the
   tongue
   The lesion site responsible is in the
   (A) stylomastoid foramen
   (B) basis pedunculi of the midbrain
   (C) rostral lateral pontine tegmentum
   (D) caudal lateral pontine tegmentum
   (E) rostral medulla

Answer 8

D. These signs constitute lateral inferior pontine syndrome (AICA syndrome). The neurologic
findings are all signs of a lesion involving the facial nerve (CN VII). The facial nerve nucleus and
intra-axial fibers are found in the caudal lateral pontine tegmentum. A lesion of the stylomastoid
foramen would not include the absence of the stapedial reflex or the loss of taste sensation from
the anterior two-thirds of the tongue. The stapedial nerve and the chorda tympani exit the facial
canal proximal to the stylomastoid foramen.

Question 9

9. Paramedian infarction of the base of the
   pons involves which one of the following struc-tures?
   (A) Trapezoid body
   (B) Descending trigeminal tract
   (C) Rubrospinal tract
   (D) Pyramidal tract
   (E) Ventral spinocerebellar tract

Answer 9

D. The base of the pons includes corticospinal (pyramidal), corticobulbar, and corticopontine
tracts, pontine nuclei, and transverse pontine fibers. At caudal levels, intra-axial abducent fibers
of CN VI pass through the lateral pyramidal fascicles.

Question 10

10. All of the following statements concern-ing the anterior spinal artery are correct
    EXCEPT it
    (A) is a branch of the vertebral artery
    (B) irrigates the medullary pyramid
    (C) irrigates the root fibers of the hypoglos-sal nerve
    (D) irrigates the inferior olivary nucleus
    (E) irrigates the medial lemniscu

Answer 10

D. The anterior (ventral) spinal artery, a branch of the vertebral artery, irrigates the ventral
median zone of the medulla, which includes the pyramid (corticospinal tracts), the medial lem-niscus, and the exiting intra-axial root fibers of the hypoglossal nerve (CN XII). The inferior oli-vary nucleus lies in the paramedian zone of the medulla and is supplied by the short lateral
branches of the vertebral artery.

Question 11

11. All of the following statements concern-ing the posterior inferior cerebellar artery
    (PICA) are correct EXCEPT it
    (A) is a branch of the vertebral artery
    (B) supplies the vestibular nuclei in the
    medulla
    (C) supplies the medial lemniscus in the
    medulla
    (D) supplies the inferior cerebellar peduncle
    (E) supplies the lateral spinothalamic tract

Answer 11

C. The posterior inferior cerebellar artery (PICA), a branch of the vertebral artery, perfuses
the lateral zone of the medulla, which includes the medial and inferior vestibular nuclei, the infe-rior cerebellar peduncle, and the lateral spinothalamic tract.

Question 12

12. All of the following statements concern-ing the anterior inferior cerebellar artery
    (AICA) are correct EXCEPT it
    (A) gives rise, in most cases, to the labyrin-thine artery
    (B) supplies the cochlear nuclei
    (C) supplies the facial nucleus
    (D) supplies the medial longitudinal fascicu-lus (MLF)
    (E) supplies the spinal trigeminal tract and
    nucleus

Answer 12

D. The anterior inferior cerebellar artery (AICA) usually (in 85% of cases) gives rise to the
labyrinthine artery. The AICA supplies the lateral zone of the caudal pontine tegmentum
(including the cochlear nuclei, the facial nucleus, and intra-axial fibers) and the spinal trigeminal
nucleus and tract. The medial longitudinal fasciculus (MLF) is irrigated by paramedian penetrat-ing branches of the basilar artery.

Question 13

13. All of the following statements concern-ing internuclear ophthalmoplegia are correct
    EXCEPT it
    (A) results from a lesion in the dorsal pon-tine tegmentum
    (B) has no affect on convergence
    (C) is frequently seen in multiple sclerosis
    (D) results in monocular horizontal nystag-mus
    (E) results in a lateral rectus palsy on at-tempted lateral conjugate gaze

Answer 13

E. Internuclear ophthalmoplegia results from a lesion of the medial longitudinal fasciculus
(MLF), which extends in the dorsomedial tegmentum from the abducent nucleus of CN VI to the
oculomotor nucleus of CN III. Transection of the MLF results in medial rectus palsy on
attempted lateral gaze and monocular nystagmus in the abducting eye. Convergence is normal.
Bilateral MLF syndrome is a common ocular motor manifestation of multiple sclerosis

Question 14

1. The most common cause of anterior vermis 
syndrome is 
(A) alcohol abuse 
(B) an abscess 
(C) a tumor 
(D) vascular occlusion 
(E) lead intoxication

Answer 14

A. Anterior vermis syndrome is a result of chronic alcohol abuse. Patients present with dys-taxia of the lower limb and trunk. Posterior vermis syndrome involves the flocculonodular lobe;
it is most frequently caused by an ependymoma or a medulloblastoma. Patients have truncal
dystaxia. Hemispheric syndrome usually is the result of a tumor (astrocytoma) or abscess;
patients have arm, leg, trunk, and gait dystaxia.

Question 15

2. The most common cerebellar tumor in chil-dren is 
(A) astrocytoma 
(B) ependymoma 
(C) glioblastoma multiforme 
(D) oligodendrocytoma 
(E) medulloblastoma

Answer 15

A. Astrocytomas (30%) are the most common cerebellar tumors in children; they are fol-lowed by medulloblastomas (20%) and ependymomas (10%).

Question 16

3. A tumor that is derived from the external
   granular layer of the cerebellar cortex is
   (A) astrocytoma
   (B) chordoma
   (C) ependymoma
   (D) germinoma
   (E) medulloblastoma

Answer 16

E. Medulloblastomas are derived from the external granular layer of the cerebellar cortex.
Medulloblastomas give rise to posterior vermis syndrome.

Question 17

4. The inferior cerebellar peduncle contains 
all of the following afferent connections 
EXCEPT the 
(A) cuneocerebellar tract 
(B) ventral spinocerebellar tract 
(C) dorsal spinocerebellar tract 
(D) olivocerebellar tract 
(E) trigeminocerebellar fibers

Answer 17

B. The ventral spinocerebellar tract enters the cerebellum via the superior cerebellar
peduncle

Question 18

5. All of the following statements concerning
   the superior cerebellar peduncle are correct
   EXCEPT it
   (A) connects the cerebellum to the midbrain
   (B) is primarily an efferent bundle of fibers
   (C) represents the major output from the
   cerebellum
   (D) contains dentatothalamic fibers
   (E) contains the juxtarestiform body

Answer 18

E. The inferior cerebellar peduncle includes the restiform body and the juxtarestiform body.
The juxtarestiform body contains vestibulocerebellar, cerebellovestibular, and cerebelloreticu-lar fibers.

Question 19

6. All of the following statements concerning
   the vestibulocerebellar pathway are correct
   EXCEPT it
   (A) plays a role in the initiation, planning,
   and timing of voluntary motor activities
   (B) projects via the medial longitudinal
   fasciculus (MLF)
   (C) receives input from the cristae am-pullares
   (D) receives input from the maculae of the
   utricle and saccule
   (E) includes the flocculonodular lobe

Answer 19

A. The vestibulocerebellum (archicerebellum) plays a role in the maintenance of posture
and balance and in the coordination of head and eye movements.

Question 20

7. All of the following statements concerning
   the red nucleus are correct EXCEPT
   (A) it influences the cerebellum via the infe-rior olivary nucleus
   (B) its primary effect is on truncal and proxi-mal muscles
   (C) it receives bilateral input from the motor
   and premotor cortex
   (D) it receives contralateral input from the
   nucleus interpositus
   (E) it receives modest input from the con-tralateral dentate nucleus

Answer 20

B. The red nucleus gives rise to the crossed rubrospinal tract, which has its primary effect
on distal muscle groups. The red nucleus is a way station in the paravermal spinocerebellar
pathway, a system dedicated to distal motor control and ongoing execution of motor acts

Question 21

8. All of the following statements concerning
   the neocerebellar pathway are correct
   EXCEPT
   (A) the neocerebellar pathway influences the
   motor cortex via the ventral anterior
   thalamic nucleus
   (B) the dentatothalamic tract decussates in
   the midbrain
   (C) the corticopontocerebellar tract decus-sates in the base of the pons
   (D) the neocerebellum expresses itself via
   the corticospinal tract
   (E) the dentate nucleus is reciprocally con-nected with the inferior olivary nucleus

Answer 21

A. In the neocerebellar pathway, the dentate nucleus projects to the contralateral ventral
lateral nucleus of the thalamus, which in turn projects to the motor cortex. The motor cortex
gives rise to the crossed corticopontocerebellar tract, which then modifies further cerebellar
output to the neocortex. The motor cortex also gives rise to the corticospinal and corticobulbar
tracts. The neocerebellum thus expresses itself via the corticospinal (pyramidal) and cortico-bulbar (corticonuclear) tracts.

Question 22

9. Signs of cerebellar dysfunction include all 
of the following EXCEPT 
(A) hypotonia 
(B) slurred or scanning speech 
(C) resting static pill-rolling tremor 
(D) dysdiadochokinesia 
(E) decomposition of movement

Answer 22

C. Cerebellar signs include hypotonia, disequilibrium, muscle incoordination (dyssynergia),
and nystagmus. Intention tremor is a variation of dysmetria (inability to correctly meter dis-tances) and is commonly seen in lesions of the cerebellar hemispheres or their central projec-tions. Dysdiadochokinesia is the inability to perform rapid alternating movements.
Decomposition of movement is a breakdown of smooth muscular movement into a number of
component steps. A resting static pill-rolling tremor is seen in Parkinson’s disease.

Question 23

10. All of the following statements concern-ing cerebellar nuclei are correct EXCEPT
    (A) the fastigial nucleus projects to the thal-amus
    (B) the fastigial nucleus projects to the
    brainstem via the superior and inferior
    cerebellar peduncles
    (C) the fastigial nucleus and the emboliform
    nucleus are called the interposed nucleus
    (D) the dentate nucleus produces the bulk of
    the axons found in the superior cerebel-lar peduncle
    (E) Purkinje cells project to all of the cerebel-lar nuclei

Answer 23

C. The emboliform and globose nuclei are called the interposed nucleus. The fastigial
nucleus projects to the vestibular nuclei via the uncinate fasciculus (a component of the supe-rior cerebellar peduncle) and via the juxtarestiform body (a component of the inferior cerebel-lar peduncle). The dentate nucleus, the largest of the cerebellar nuclei, gives rise to the bulk of
the axons in the superior cerebellar peduncle.

Question 24

11. All of the following statements concern-ing the cerebellum are correct EXCEPT it
    (A) contains four pairs of nuclei within its
    medullary body
    (B) contains two pairs of cerebellar pedun-cles
    (C) consists of a midline vermis and two lat-eral hemispheres
    (D) is located infratentorially within the pos-terior fossa
    (E) has a three-layered cortex

Answer 24

B. The cerebellum is attached to the brainstem by three pairs of cerebellar peduncles:
Superior cerebellar peduncles connect to the pons and midbrain; middle cerebellar peduncles
connect to the pons; and inferior cerebellar peduncles attach to the medulla.

Question 25

12. All of the following statements concern-ing the cerebellum are correct EXCEPT it
    (A) projects to the red nucleus
    (B) projects to the vestibular nuclei
    (C) projects to the lateral ventral nucleus of
    the thalamus
    (D) receives input from the superior olivary
    nucleus
    (E) receives the olivocerebellar tract via the
    inferior cerebellar peduncle

Answer 25

D. The superior olivary nucleus is a relay nucleus of the auditory system and does not pro-ject to the cerebellum. The inferior olivary nucleus of the medulla projects to the cerebellum
via the inferior cerebellar peduncle.

Question 26

13. All of the following statements concern-ing the cerebellum are correct EXCEPT it 
(A) is derived from the alar plate 
(B) develops from the rhombic lips 
(C) is part of the metencephalon 
(D) is part of the rhombencephalon 
(E) is part of the brainstem

Answer 26

-E. The cerebellum develops from the rhombic lips of the alar plates. The metencephalon
(afterbrain) consists of the pons and cerebellum; the rhombencephalon (hindbrain) includes the
metencephalon and the myelencephalon (medulla oblongata). The brainstem (truncus cerebri)
includes the midbrain, pons, and medulla oblongata; some authorities also include the dien-cephalon.

Question 27

14. All of the following statements concerning
    the dentate nucleus are correct EXCEPT it
    (A) receives input from climbing and mossy
    fibers
    (B) receives inhibitory input from Purkinje
    cells
    (C) gives rise to the superior cerebellar
    peduncle
    (D) gives rise to the fascia dentata
    (E) projects to the ventral lateral nucleus of
    the thalamus

Answer 27

D. The dentate nucleus is innervated by climbing and mossy fibers and receives inhibitory
input from the Purkinje cells of the cerebellar cortex. It gives rise to most of the fibers in the
superior cerebellar peduncle (i.e., the dentatorubrothalamic tract). The dentate nucleus pro-jects to the ventral lateral and ventral posterolateral nuclei of the thalamus; these thalamic
nuclei project to the motor cortex. The fascia dentata (dentate gyrus) is a structure of the hip-pocampal formation.

Question 28

15. All of the following statements concern-ing Friedreich’s ataxia are correct EXCEPT
    (A) it has the same spinal cord pathology as
    vitamin B
    1 2
    neuropathy
    (B) it is the most common of the hereditary
    ataxias
    (C) it has an autosomal dominant mode of
    inheritance
    (D) plantar reflexes are bilaterally extensor
    (E) it is frequently associated with chronic
    myocarditis

Answer 28

C. Friedreich’s ataxia is transmitted as an autosomal recessive trait. It is the most com-mon of the hereditary ataxias.

Question 29

16. All of the following statements concern-ing cerebello-olivary atrophy are correct
    EXCEPT
    (A) there is a loss of Purkinje cells
    (B) there is a loss of neurons in the inferior
    olivary nuclei
    (C) there is a loss of cells in the substantia
    nigra
    (D) the cell loss in the inferior olivary
    nucleus is due to a primary loss of
    Purkinje cells
    (E) it has an autosomal dominant mode of
    inheritanc

Answer 29

C. With cerebello-olivary atrophy, there is no loss of cells in the substantia nigra. With
olivopontocerebellar atrophy, there is frequently a loss of neurons in the substantia nigra.

Question 30

1. Which of the following thalamic nuclei has 
a motor function? 
(A) Lateral dorsal nucleus 
(B) Mediodorsal nucleus 
(C) Ventral lateral nucleus 
(D) Ventral posterior nucleus 
(E) Lateral posterior nucleus

Answer 30

C. The ventral lateral nucleus receives motor input from the extrapyramidal (striatal) motor
system (globus pallidus and substantia nigra) and from the cerebellum (dentate nucleus).

Question 31

2. Spinothalamic fibers project to which one
   of the following thalamic nuclei?
   (A) Ventral posteromedial (VPM) nucleus
   (B) Pulvinar
   (C) Ventral anterior nucleus
   (D) Ventral posterolateral (VPL) nucleus
   (E) Anterior nucleus

Answer 31

D. Spinothalamic fibers project to the ventral posterolateral (VPL) nucleus, which receives the
medial lemniscus.

Question 32

3. Cerebellar fibers project to which one of 
the following thalamic nuclei? 
(A) Ventral posteromedial (VPM) nucleus 
(B) Lateral dorsal nucleus 
(C) Lateral posterior nucleus 
(D) Ventral lateral nucleus 
(E) Anterior nucleus

Answer 32

D. Cerebellar fibers (dentatocerebellar) project to the ventral lateral and ventral posterolat-eral (VPL) nuclei, which project to the motor cortex (area 4)

Question 33

4. The globus pallidus projects to which one
   set of thalamic nuclei?
   (A) Centromedian, ventral anterior, and ven-tral lateral nuclei
   (B ) Ventral anterior, ventral lateral, and
   anterior nuclei
   (C) Ventral lateral, lateral dorsal, and lat-eral posterior nuclei
   (D) Mediodorsal, ventral posterolateral (VPL),
   and ventral posteromedial (VPM) nuclei
   (E) Centromedian, lateral dorsal, and lateral
   ventral nucle

Answer 33

A. The globus pallidus, a nucleus of the extrapyramidal (striatal) motor system, projects to
three thalamic nuclei: the centromedian, the ventral anterior, and the ventral lateral nuclei of
the thalamus

Question 34

5. The thalamus receives precortical sensory 
input from all of the following modalities 
EXCEPT 
(A) general somatic sense 
(B) gustation 
(C) vision 
(D) audition 
(E) olfaction

Answer 34

E. The thalamus receives precortical input from all sensory systems except the olfactory sys-tem. The olfactory pathway reaches the primary olfactory cortex (prepiriform and periamyg-daloid cortex) without a relay in the thalamus.

Question 35

6. All of the following statements concerning
   the mediodorsal nucleus are correct EXCEPT
   it
   (A) receives input from the amygdaloid
   nucleus
   (B) receives input from the intralaminar
   nuclei
   (C) is part of the limbic system
   (D) is part of the extrapyramidal motor sys-tem
   (E) has reciprocal connections with the pre-frontal cortex

Answer 35

D. The mediodorsal nucleus plays an important role in the expression of affect, emotion, and
behavior. It is a limbic structure. The mediodorsal nucleus is not a part of the extrapyramidal
motor system.

Question 36

7. All of the following statements concerning
   the lateral geniculate body (LGB) are correct
   EXCEPT it
   (A) projects to the lingual gyrus
   (B) projects to the cuneus
   (C) receives input from the retina
   (D) receives input from the lateral lemniscus
   (E) receives its blood supply from the ante-rior choroidal artery

Answer 36

D. The lateral geniculate body (LGB) receives input from the retina and projects to the visual
cortex (lingual gyrus and cuneus). It is irrigated by the anterior choroidal artery and the poste-rior cerebral artery (thalamogeniculate arteries). The lateral lemniscus is an auditory pathway.

Question 37

8. All of the following statements concerning
   the pulvinar are correct EXCEPT
   (A) it is the largest nucleus of the thalamus
   (B) it receives input from the visual associa-tion cortex
   (C) it receives input from the superior col-liculus
   (D) it has reciprocal connections with the
   parietal association cortex
   (E) a lesion results in a contralateral hemi-anopia

Answer 37

E. The pulvinar, the largest nucleus of the thalamus, is a dorsal tier nucleus and has recipro-cal connections with the visual association cortex (areas 18 and 19). The pulvinar is reciprocally 
connected with the parietal association cortex (areas 39 and 40). It also receives input from the 
superior colliculus and the pretectal area. Destruction of the pulvinar does not result in a visual 
field deficit (hemianopia).

Question 38

9. Infarction of the right internal capsule 
could result in all of the folio wing defects 
EXCEPT 
(A) left hypesthesia 
(B) right homonymous hemianopia 
(C) left facial weakness 
(D) tongue deviates to left side 
(E) plantar reflex extensor on left side

Answer 38

B. Infarction of the right internal capsule could result in a left homonymous hemianopia.

Question 39

10. A capsular stroke is most commonly 
caused by occlusion of which of the following 
arteries? 
(A) Anterior cerebral artery 
(B) Recurrent artery of Heubner 
(C) Medial striate arteries 
(D) Posterior communicating artery 
(E) Direct branches of the internal carotid 
artery

Answer 39

C. A capsular stroke is most commonly caused by occlusion of the medial striate branches of
the middle cerebral artery.

Question 40

1. Interruption of the medial longitudinal
   fasciculus (MLF) at pontine levels
   (A) results in miosis and ptosis
   (B) results in paralysis of upward gaze on
   command
   (C) results in paralysis of lateral gaze on
   command
   (D) abolishes convergence
   (E) abolishes accommodation

Answer 40

C. Interruption of the pontine medial longitudinal fasciculus (MLF) results in a medial rec-tus palsy on attempted conjugate lateral gaze. Convergence remains intact. This syndrome,
called internuclear ophthalmoplegia or MLF syndrome, is commonly seen in multiple sclerosis.

Question 41

2. All of the following statements concerning
   the optic chiasm are correct EXCEPT
   (A) its primary blood supply is from the ante-rior cerebral and internal carotid arteries
   (B) it lies dorsal to the diaphragma sellae
   (C) the midsagittal section results in binasal
   hemianopia
   (D) it contains uncrossed fibers from the tem-poral hemiretinae
   (E) it contains pupillary fibers en route to
   the pretectum

Answer 41

C. The midsagittal section of the optic chiasm transects fibers from the nasal hemiretinae,
resulting in a bitemporal hemianopia.

Question 42

3. All of the following statements concerning
   the lateral geniculate body (LGB) are correct
   EXCEPT
   (A) it is a thalamic nucleus
   (B) it receives input from the contralateral
   visual field
   (C) it is irrigated by the posterior cerebral
   artery and the anterior choroidal artery
   (D) destruction results in bitemporal hemi-anopia
   (E) it projects to the lingual gyrus and the
   cuneu

Answer 42

D. Destruction of the optic tract, the lateral geniculate body (LGB), or the geniculocalcarine
tract all result in the same visual field defect, a contralateral homonymous hemianopia.

Question 43

4. All of the following statements concerning
   the visual cortex are correct EXCEPT
   (A) it corresponds to area 17
   (B) it is located on the banks of the calcarine
   sulcus
   (C) destruction of the upper bank of the cal-carine sulcus results in a lower ipsilat-eral homonymous quadrantanopia
   (D) cortical lesions are characterized by mac-ular sparing
   (E) it is irrigated by a branch of the posterior
   cerebral artery

Answer 43

C. Destruction of the upper bank of the calcarine sulcus interrupts lateral geniculate body
(LGB) fibers, which represent the upper ipsilateral retinal quadrants. The field defect is called
a lower contralateral homonymous quadrantanopia.

Question 44

5. All of the following statements concerning
   the pupillary light pathway are correct
   EXCEPT
   (A) transection of the optic tract eliminates
   the direct pupillary light response
   (B) transection of the optic nerve would not
   eliminate the consensual pupillary light
   reflex
   (C) destruction of the lateral geniculate body
   (LGB) would not interrupt the pupillary
   light pathway
   (D) the efferent limb of the pupillary light
   reflex is the oculomotor nerve (CN III)
   (E) axons of the retinal ganglion cells medi-ating the pupillary light reflex terminate
   in the pretectal nucleus

Answer 44

A. Transection of the optic tract would not eliminate the direct pupillary response.
Pupillary fibers in the optic tract project to the pretectal nuclei, which discharge to the ipsilat-eral and contralateral Edinger-Westphal nuclei.

Question 45

6. All of the following statements concerning
   the superior colliculus are correct EXCEPT
   (A) it is the tectum of the midbrain
   (B) it receives input from the retina and
   visual cortex
   (C) it plays a role in head and eye movements
   (D) it is irrigated by the posterior communi-cating artery
   (E) a unilateral lesion results in contralat-eral neglect of visual stimuli

Answer 45

D. The superior colliculus is irrigated by the long circumflex branches of the posterior cere-bral arteries (quadrigeminal arteries).

Question 46

7. All of the following statements concerning
   the retina are correct EXCEPT
   (A) it is derived from the optic vesicle of the
   diencephalon
   (B) it is sensitive to wavelengths from 400
   nm to 700 nm
   (C) retinal ganglion cells project directly to
   the visual cortex
   (D) retinal ganglion cells project directly to
   the hypothalamus
   (E) retinal ganglion cells project directly to
   the midbrain

Answer 46

C. Retinal ganglion cells project to the lateral geniculate body (LGB), which projects to the
primary visual cortex. Retinal ganglion cells project directly to the suprachiasmatic nucleus of
the hypothalamus and to the pretectal nuclei and superior colliculus of the midbrain. The
retina is derived from the optic vesicle of the diencephalon.

Question 47

8. All of the following statements concerning
   the optic disk are correct EXCEPT it
   (A) is found nasal to the fovea centralis
   (B) is the blind spot
   (C) contains the retinal vessels
   (D) contains myelinated axons from the gan-glion cell layer
   (E) contains neither rods nor cones

Answer 47

D. The optic disk, the optic papilla, is found nasal (medial) to the fovea centralis. It contains
no rods or cones and thus represents a blind spot in the retina. The retinal vessels emerge
from the optic disk. Myelinated axons usually are not found in the retina; when they are pres-ent, they may produce a central scotoma. Myelination of the optic nerve extends from the
external part of the lamina cribrosa to the lateral geniculate body (LGB).

Question 48

9. All of the following statements concerning
   the fovea centralis are correct EXCEPT it
   (A) plays a role in photopic vision
   (B) lies within the macula lutea
   (C) contains only cones
   (D) is the optic papilla
   (E) is the site of highest visual acuity

Answer 48

D. The fovea centralis lies within the macula lutea and represents the locus of highest
visual acuity. The fovea contains only cones, thus subserving color or day (photopic) vision. The
fovea centralis lies temporal (lateral) to the optic disk. The optic disk is the optic papilla.

Question 49

10. All of the following statements concern-ing the ganglion cells of the retina are correct
    EXCEPT they
    (A) give rise to the optic nerve
    (B) receive direct input from the rods and
    cones
    (C) are derived from the diencephalon
    (D) project to the lateral geniculate body
    (LGB)
    (E) project directly to the hypothalamus

Answer 49

B. The ganglion cells of the retina give rise to the optic nerve and project to the lateral
geniculate body (LGB), the hypothalamus, the pretectal nucleus, and the superior colliculus.
Input from the rods and cones is conducted to the ganglion cells via the bipolar cells. The
retina is derived from the optic vesicle of the diencephalon. The hypothalamic projection is to
the suprachiasmatic nucleus, a circadian pacemaker.

Question 50

11. All of the following statements concern-ing the optic nerve are correct EXCEPT
    (A) it is a myelinated tract of the central ner-vous system (CNS)
    (B) it is a true peripheral nerve
    (C) it is invested by leptomeninges
    (D) it is incapable of regeneration
    (E) its cells of origin are found in the gan-glion cell layer of the retina

Answer 50

-B. The optic nerve is a myelinated tract of the central nervous system (CNS) that is
invested by the leptomeninges and the dura mater. Its cells of origin are found in the ganglion
cell layer of the retina. It is incapable of regeneration.

Question 51

12. All of the following statements concern-ing the subcortical center for lateral gaze are
    correct EXCEPT it
    (A) receives input from the contralateral
    frontal lobe
    (B) projects to the contralateral medial longi-tudinal fasciculus (MLF)
    (C) is found in the pons
    (D) is found in the midbrain
    (E) is found within a cranial nerve nucleus

Answer 51

D. The subcortical center for lateral gaze is found in the abducent nucleus of the pons,
receives input from the contralateral frontal eye field (area 8), and projects to the contralateral
medial longitudinal fasciculus (MLF). Destruction of the abducent nucleus results in an ipsi-lateral lateral rectus paralysis and a contralateral medial rectus palsy on attempted lateral
gaze. The subcortical center for vertical conjugate gaze is located in the midbrain at the level of
the posterior commissure.