Cerebellum

Question 1

Describe the functions of the three functional divisions of the cerebellum.

Cerebrocerebellum

Answer 1

Pontine nuclei

Functions in coordination of voluntary movements, planning of movements, and timing

Question 2

Describe the functions of the three functional divisions of the cerebellum.

Spinocerebellum

Answer 2

Vermis and paravermal region
Somatosensory info
Functions to control ongoing movement via the brainstem descending tracts

Question 3

Describe the functions of the three functional divisions of the cerebellum.

Vestibulocerebellum

Answer 3

Flocculonodular lobe
Receives info directly from vestibular receptors
Functions to influence eye movements and postural muscles of head and body

Question 4

Define cerebellar ataxia.

Answer 4

Sudden, uncoordinated muscle movement due to disease or injury to the cerebellum

Question 5

Evaluate the clinical findings of midline ataxia.

Answer 5

Vestibulocerebellum or spinocerebellum lesion
Truncal instability
Titubation
Gait ataxia: wide base, irregular steps
Lateral veering if only 1 side is affected

Question 6

5Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Dorsal spinocerebellar tract

Answer 6

Conveys unconscious, precise proprioceptive info from the lower ½ of the body and lower extremities to the cerebellum
Originates in nucleus dorsalis, courses through ipsilateral inferior cerebellar peduncle, and terminates in anterior vermis of cerebellum

Question 7

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Direct Arcuate Fibers (Cuneocerebellar fibers)

Answer 7

Unconscious, precise proprioceptive info to upper ½ of body

Accessory cuneate nucleus –> vermis

Question 8

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Trigeminocerebellar tract

Answer 8

Unconscious sensory tract to face

General proprioceptive and exteroceptive info from the head

Question 9

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Arcuocerebellar fibers

Answer 9

Form cerebro-cerebellar feedback loop

Originate in arcuate nuclei –> contralateral cerebellar hemisphere via external arcuate fibers

Question 10

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Reticulocerebellar fibers

Answer 10

Reticulocerebellar fibers
General sensory modalities to the cerebellum
Lateral reticular nuclei –> cerebellar hemispheres (bilaterally)

Question 11

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Inferior cerebellar peduncle (DDT Always Ruins Olives)

Olivocerebellar fibers

Answer 11

Inferior olivary nucleus (as afferent fibers) –> contralateral cerebellar hemisphere (as climbing fibers)

Question 12

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Middle cerebellar peduncle

Pontocerebellar fibers

Answer 12

Originate in pontine nuclei
Project to cerebellar cortex and dentate nucleus
Form feedback loop between the motor cortex and cerebellum

Question 13

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Middle cerebellar peduncle

Corticopontine fibers

Answer 13

Terminate in ipsilateral pontine nuclei, which project to the cortex of the contralateral cerebellar hemisphere

Question 14

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Superior cerebellar peduncle

Ventral spinocerebellar tract (VSCT)

Answer 14

General proprioceptive info from lumbosacral levels to cerebellum
 Neurons in dorsal horn and intermediate gray –> decussates in AWC –> ascends in lateral funiculus –> passes through superior cerebellar peduncle —> terminates in anterior vermis

Question 15

Describe the organization of fibers entering or leaving the cerebellar peduncles.

Superior cerebellar peduncle

Trigeminocerebellar tract

Answer 15

Arises from main sensory nucleus of V and projects to anterior vermis of cerebellum via superior cerebellar peduncle

Unconscious, precise tactile and proprioceptive info from the head to the cerebellum

Question 16

Describe the flow of information into and out of the cerebellum (afferents, deep nuclei,
efferents.)

Answer 16

Fastigial and medial portion of the globose
Send efferent fibers into vestibular system
Via direct and indirect fastigiobulbar fibers

Lateral globose, emboliform, and denticulate nuclei
Project through superior cerebellar peduncle
Decussate in the upper pons and lower midbrain
Ascending limb of superior cerebellar peduncle
Dentato-rubro-thalamic fibers
Dentato-thalamic fibers

Descending limb of superior cerebellar peduncle
ION and lateral reticular nucleus

Question 17

Nystagmus

Answer 17

Lesions of vestibulocerebellum may result in this
Eyes make repetitive, uncontrolled movements
Can result in reduced vision and depth perception and can affect balance and coordination

Question 18

Dysdiadochokinesia

Answer 18

Inability to perform rapidly altering movements such as pronation and supination

Question 19

Dysmetria

Answer 19

Literally “missing the mark” during such tests as touching the fingertip to the nose with the eyes closed

Question 20

Action tremor

Answer 20

Characteristic of lesions involving the superior cerebellar peduncle or dentate nucleus
Present during voluntary movements such as reaching for a pencil on a table and absent during rest
As pt reaches for object, the tremor progressively worsens

Question 21

Dysarthria

Answer 21

Motor speech disorder where muscles used to produce speech are damaged, paralyzed, or weakened
Person can’t control their tongue, larynx, vocal cords, and surrounding muscles
Speech is often jerky, staccato, breathy, irregular, imprecise, or monotonous

Question 22

Decomposition of movement

Answer 22

Movements tend to be performed one joint at a time and take on a “robotic” appearance

Question 23

Determine the best test(s) to perform to examine the function of the vestibulocerebellum

Answer 23

o Romberg test
o Examine gait for ataxia
o Make patient walk in tandem, on their heels, and on their toes
o Examine for nystagmus – fast phase toward side of cerebellar lesion
o Controls balance and ocular reflexes

Question 24

Determine the best test(s) to perform to examine the function of the Spinocerebellum

Answer 24

o Romberg test
o Examine gait for ataxia
o Pronator drift
Tapping pts arms down
Effected pt may overcorrect as they will lack proper proprioception
o Controls body movements by allowing for error correction; also receives proprioceptive info

Question 25

Determine the best test(s) to perform to examine the function of the Cerebrocerebellum

Answer 25

o Formed by lateral hemispheres
o Involved in planning movements and motor learning
o Regulates coordination of muscle activation and is important in visually guided movements
o Test function with finger-to-nose, finger-to-finger; rapid alternating movements

Question 26

What signs and symptoms would you see with a Lesion to flocculonodular lobe or midline structures like nodulus and fastigial nucleus

Answer 26

o Unsteady, lurching gait (truncal ataxia)
o Tendency to fall
o Unable to walk in tandem
o Tremor of the ataxial body or head (titubation)
o Nystagmus with possible head tilt to one side

Question 27

What signs and symptoms would you see with a Lesion of cerebellar hemisphere

Answer 27

o Motor deficits on the ipsilateral side of the body

 Due to mediation primarily through corticospinal and rubrospinal pathways

Question 28

What signs and symptoms would you see with Atrophy of anterior lobe of cerebellum, neocerebellum, and dentate nucleus

Answer 28

Severe ataxia of lower extremities and trunk

Can be seen in conjunction with Korsakoff’s syndrome

Question 29

What signs and symptoms would you see with a Unilateral cerebellar lesion

Answer 29

o Ipsilateral deficits seen

Question 30

What signs and symptoms would you see with a Lesion of lateral cerebellum

Answer 30

o Deterioration of coordination of movement (decomposition of movement)
o Hypotonia
o Ataxia
o Dysmetria
o Active tremor
o Failure of heel-to-shin test
o Dysdiadochokinesia
o Rebound phenomena, dysarthria, ocular motor dysfunction
Nystagmus with fast portion toward the side of the lesion

Question 31

What signs and symptoms would you see with a Lesion distal to decussation of superior cerebellar peduncle

Answer 31

Deficits on the side opposite the lesion

Question 32

What signs and symptoms would you see with a Midline lesion

Answer 32

Bilateral deficits restricted to axial or truncal parts of the body