Chapter 15

Question 1

1. A 30-year-old woman complains of unsteadi-
   ness while standing or walking. She tends to
   deviate to the right. Neurologic examination
   reveals the following signs: dysmetria on the
   right, dysdiadochokinesia, and a nystagmus
   that is more marked when she looks to the
   right side. The lesion is most likely found in the
   (A) cerebellar hemisphere, left side
   (B) cerebellar hemisphere, right side
   (C) medial medulla, left side
   (D) medial medulla, right side
   (E) globus pallidus, left side

Answer 1

l-B. Dysmetria, dysdiachokinesia, intention tremor, and nystagmus are classic cerebellar signs.
In the finger-to-nose test, the patient past-points on the side of the lesion. The medial medulla
has no cerebellar pathways. In contrast, the lateral medulla has cerebellar pathways; lesions re-
sult in cerebellar ataxia and could be misdiagnosed as a cerebellar hemispheric lesion. The
globus pallidus, a basal ganglion, is atrophied in Huntington disease and in Wilson disease, and
it is damaged bilaterally by carbon monoxide intoxication.

Question 2

2. Purkinje cells of the cerebellum project in-
   hibitory axons to which of the following nuclei?
   (A) Fastigial nucleus
   (B) Superior olivary nucleus
   (C) Inferior olivary nucleus
   (D) Arcuate nucleus
   (E) Ventral lateral nucleus

Answer 2

2-A. Purkinje cells project inhibitory axons to all cerebellar nuclei: fastigial, globose, embo-
liform, and dentate. In addition, they project to all vestibular nuclei: lateral, superior, medial,
and inferior. The superior olivary nucleus is an auditory relay nucleus, and the inferior olivary
nucleus is a cerebellar relay nucleus. The arcuate nucleus is an ectopic pontine nucleus that lies
next to the pyramidal tract; its function is unknown. The ventral lateral thalamic nucleus re-
ceives input from the dentate nucleus.

Question 3

3.	The most common cause of the anterior ver-
mis syndrome is
(A)	alcohol abuse
(B)	an abscess
(C)	a tumor
(D)	vascular occlusion
(E)	lead intoxication

Answer 3

3-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 dys-
taxia. Hemispheric syndrome usually is the result of a tumor (astrocytoma) or abscess; patients
have arm, leg, trunk, and gait dystaxia.

Question 4

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

Answer 4

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

Question 5

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

Answer 5

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

Question 6

6.	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 6

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

Question 7

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

Answer 7

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

Question 8

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

Answer 8

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

Question 9

9. 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 9

9-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 path-
way, a system dedicated to distal motor control and ongoing execution of motor acts.

Question 10

10. All of the following statements concerning
    the neocerebellar pathway are correct EXCEPT
    (A) the neocerebellar pathway influences the
    motor cortex via the ventral anterior thal-
    amic nucleus
    (B) the dentatothalamic tract decussates in
    the midbrain
    (C) the corticopontocerebellar tract decussates
    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 10

10-A. In the neocerebellar pathway, the dentate nucleus projects to the contralateral ventral lat-
eral 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, as well as to the corticospinal and corticobulbar tracts. The neocerebellum thus
expresses itself via the corticospinal (pyramidal) and corticobulbar (corticonuclear) tracts.

Question 11

11.	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 11

11-C. Cerebellar signs include hypotonia, disequilibrium, muscle incoordination (dyssynergia),
and nystagmus. Intention tremor is a variation of dysmetria (inability to estimate distances cor-
rectly) and is commonly seen in lesions of the cerebellar hemispheres or their central projections.
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 disease.

Question 12

12. All of the following statements concerning
    cerebellar nuclei are correct EXCEPT
    (A) the fastigial nucleus projects to the thala-
    mus
    (B) the fastigial nucleus projects to the brain-
    stem via the superior and inferior cere-
    bellar 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 cerebellar
    peduncle
    (E) Purkinje cells project to all of the cerebellar
    nuclei

Answer 12

12-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 superior cere-
bellar peduncle) and via the juxtarestiform body (a component of the inferior cerebellar peduncle). The dentate nucleus, the largest of the cerebellar nuclei, gives rise to the bulk of the axons
in the superior cerebellar peduncle.

Question 13

13. All of the following statements concerning
    the cerebellum are correct EXCEPT
    (A) it contains four pairs of nuclei within its
    medullary body
    (B) it contains two pairs of cerebellar peduncles
    (C) it consists of a midline vermis and two
    lateral hemispheres
    (D) it is located infratentorially within the
    posterior fossa
    (E) it has a three-layered cortex

Answer 13

13-B. The cerebellum is attached to the brainstem by three pairs of cerebellar peduncles: Su-
perior cerebellar peduncles connect to the pons and midbrain; middle cerebellar peduncles con-
nect to the pons; and inferior cerebellar peduncles attach to the medulla.

Question 14

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

Answer 14

14-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 15

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

Answer 15

15-E. The cerebellum develops from the rhombic lips of the alar plates. The metencephalon (af-
terbrain) consists of the pons and cerebellum, and the rhombencephalon (hindbrain) includes the
metencephalon and the myelencephalon (medulla oblongata). The brainstem (truncus cerebri) in-
cludes the midbrain, pons, and medulla oblongata; some authorities also include the diencephalon.

Question 16

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

Answer 16

16-D. The dentate nucleus is innervated by climbing and mossy fibers and receives inhibitory in-
put from the Purkinje cells of the cerebellar cortex. It gives rise to most of the fibers in the supe-
rior cerebellar peduncle (i.e., the dentatorubrothalamic tract). The dentate nucleus projects 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 hippocampal formation.

Question 17

17. All of the following statements concerning
    Friedreich ataxia are correct EXCEPT
    (A) it has the same spinal cord pathology as
    vitamin B12 neuropathy
    (B) it is the most common of the hereditary
    ataxias
    (C) it has an autosomal dominant mode of in-
    heritance
    (D) plantar reflexes are bilaterally extensor
    (E) it is frequently associated with chronic
    myocarditis

Answer 17

17-C. Friedreich ataxia is transmitted as an autosomal recessive trait. It is the most common
of the hereditary ataxias.

Question 18

18. All of the following statements concerning
    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 ni-
    gra
    (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 in-
    heritance

Answer 18

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