Lecture 11

Question 1

List the basic functions of the cerebellum

Answer 1

Compares actual movements with intended movements, aids cortex in planning next sequential movement, functions with spinal cord to enhance stretch reflex, with brain stem to make postural movements, and with cerebral cortex to provide accessory motor functions

Question 2

What are the 3 lobes of the cerebellum (anterior to posterior)?

Answer 2

Anterior lobe, posterior lobe, and flocculonodular lobe (associated with vestibular system)

Question 3

Which lobe is evolutionarily the oldest?

Answer 3

Flocculonodular lobe

Question 4

What are the folia?

Answer 4

Transversely arranged narrow gyri

Question 5

What and where is the vermis? With what functions is it associated?

Answer 5

It is the location for control functions for muscle movements of the axial body, neck, shoulders, and hips; located in the middle of the brain, separating the 2 hemispheres

Question 6

What are the general functions of the intermediate and lateral zones?

Answer 6

Intermediate Zones: Concerned with controlling muscle contractions in the distal portions of the upper an lower limbs, esp. the hands, feet, fingers, and toes

Lateral Zones: Associated with cerebral cortex with planning of sequential motor movements

Question 7

List the 4 pairs of deep cerebellar nuclei and relate lesions to their normal function

Answer 7

Dentate, emboliform, and globose nuclei: lesions in these nuclei lead to extreme ataxia

Fastigial nuclei: lesions in this nucleus lead to trunk ataxia

Question 8

List the cells that make up the cerebellar cortex and describe their circuitry

Answer 8

Granular Cells: Axons form parallel fibers in cortex (+)

Golgi Cells: Project from parallel fibers to granular cell bodies (-)

Basket Cells: Project from parallel fibers to purkinje axon hillock (-)

Stellate Cells: Project from parallel fibers to purkinje dendrites (-)

Purkinje Cells: Project to intracerebellar nuclei (-)

Question 9

Describe the functional unit of the cerebellum

Answer 9

Each functional unit is centered on a purkinje cell and a corresponding deep nuclear cell; 30 million of these in cerebellar cortex; output from a functional unit is from a deep nuclear cell

Question 10

What are pendular movements? How does the cerebellum affect pendular movements?

Answer 10

Movements that swing back and forth; all pendular movements have a tendency to overshoot, but appropriate learned subconscious signals from intact cerebellum can stop movement precisely at the intended point

Question 11

What are ballistic movements?

Answer 11

Dystonia (state of abnormal muscle tone resulting in muscular spasms and abnormal posture)

Question 12

How does removal of the cerebellum affect movements of the body?

Answer 12

Movements are slow to develop, force developed is weak, and movements are slow to turn off

Question 13

List the composition and functions of the vestibulocerebellum

Answer 13

Consists of flocculonodular lobes and vermis; functions in control of balance and eye movements and sends output primarily to vestibular system

Question 14

List the composition and functions of the spinocerebellum

Answer 14

Consists mostly of vermis and intermediate zones; functions in synergy (control of rate, force, range, and direction of movement)

Question 15

List the composition and functions of the cerebrocerebellum

Answer 15

Consists of lateral parts of hemispheres; mostly associated with premotor cortex and the primary association somatosensory areas of the cerebral cortex; also involved in coordination of skilled movement and speech

Question 16

What is dysmetria?

Answer 16

Inability to judge distance and when to stop

Question 17

What is ataxia?

Answer 17

Uncoordinated movement

Question 18

What is adiadochokinesia?

Answer 18

Inability to perform rapid alternating movements

Question 19

What is an intention tremor?

Answer 19

Movement tremors

Question 20

What is a cerebellar lesion gait?

Answer 20

Staggering, wide based walking

Question 21

What is cerebellar hypoplasia?

Answer 21

Weak muscles

Question 22

What is ataxic dysarthria?

Answer 22

Slurred speech

Question 23

What is nystagmus?

Answer 23

Abnormal eye movements

Question 24

Which afferent tracts to the cerebellum form the mossy fibers and which tracts form the climbing fibers?

Answer 24

Mossy Fibers: Corticopontocerebellar, vestibulocerebellar, reticulocerebellar, and spinocerebellar

Climbing Fibers: Olivocerebellar

Question 25

List the efferent tracts from the cerebellum

Answer 25

Cerebelloreticular, cerebellothalamocortical, cerebellorubral, and cerebellovestibular

Question 26

What are the layers of the cerebellar cortex from innermost to outermost?

Answer 26

Granular layer, purkinje cell layer, and molecular layer

Question 27

What is vestibulocerebellar syndrome?

Answer 27

Progressive genetic disease of the flocculonodular lobe; starts with abnormal eye movement including nystagmus; vertigo and tinnitus, ataxia; eventually fine motor skills are lost