Lecture 12: Cerebellum and Motor Control

Question 1

what is the Similarity with cerebrum and cerebellum

Answer 1

Two hemispheres

Question 2

does the cerebrum or cerebellum have more neurons

Answer 2

cerebellum makes up only 10% of the brain but 4x as many neurons as the cerebrum

Question 3

how does the cerebellum interact with lower motor neurons

Answer 3

Efferents do not project directly to local circuits or LMNs because it doesn’t initiate movement

Question 4

how does the cerebellum interact with upper motor neurons

Answer 4

Operates primarily by modifying the activity of UMNs to make movements more accurate

Question 5

what are the 2 parts of the cerebellum

Answer 5

Cerebellar Cortex

Cerebellar Nuclei

Question 6

are there different layers of the Cerebellar Cortex

Answer 6

yes

Question 7

what are the deep nuclei structures responsible for

Answer 7

Output neurons of the cerebellum

Question 8

how is the cerebellum divided in terms of muscle representation

Answer 8

Axial muscles represented
more centrally

Distal muscles represented more laterally

(sort of somatotopic)

Question 9

what are the 3 Functional Divisions of the Cerebellum

Answer 9

Vestibulocerebellum

Spinocerebellum

Cerebrocerebellum

Question 10

what is the function of the Vestibulocerebellum division

Answer 10

Postural Control

Question 11

what is the function of the Spinocerebellum division

Answer 11

Gross movements of the trunk and limbs

Question 12

what is the function of the Cerebrocerebellum division

Answer 12

Fine motor voluntary movements

Question 13

what are Cerebellar peduncles

Answer 13

Connections between cerebellum and other parts of the CNS

Question 14

what is the closed Cerebro-cerebello-cerebral loop

Answer 14

Output to corticospinal tract double crosses = ipsilateral representation

Question 15

what are the 3 main functions of the cerebellum

Answer 15

Coordination of multi-jointed movement

Postural control

error correction

Question 16

how does the cerebellum perform error correction

Answer 16

Integrates executive commands with sensory feedback

Question 17

how does the cerebrum compare intended and actual movement (4 steps)

Answer 17

initial feedforward blueprint (efference copy)

Cerebellum predict the amount of sensory input

Sensory inputs provide afferent copy/feedback

Cerebellum compares predicted sensory input with actual sensory input to reduce error

Question 18

do cerebellar lesions cause ipselateral or contralateral leisons

Answer 18

ipsilateral

Question 19

what are the 3 signs of a cerebellar lesion

Answer 19

ataxia (incoordination)

poor postural control

difficulty learning highly skilled sequences

Question 20

do we see sensory or strength issues with a cerebellar lesion

Answer 20

no

Question 21

what 3 things do we see with Vestibulocerebellum damage

Answer 21

Spontaneous nystagmus

Postural instability

Truncal ataxia

Question 22

what do we see with Spinocerebellum damage

Answer 22

Damage to vermis
* Truncal ataxia

Damage to paravermis
* Limb ataxia
* Ataxic gait

Question 23

what do we see with Cerebrocerebellar damage

Answer 23

Loss of coordination of fine finger movements

Question 24

what are the 3 types of limb ataxia

Answer 24

intention tremor

dysmetria

dysdiadochokinesia

Question 25

what is intention tremor

Answer 25

Tremor during movement
that increases as you reach target

Question 26

what is Dysmetria

Answer 26

Inability to gauge the distance (overshooting or undershooting)

Question 27

what is Dysdiadochokinesia

Answer 27

Difficulty performing rapid alternating movements

Question 28

what is motor control

Answer 28

The ability to regulate or direct the mechanisms essential to movement

Question 29

Normal motor control relies heavily on which 3 types of information:

Answer 29

visual

somatosensory

vestibular

Question 30

why are Basal Ganglia and Cerebellum heavily involved in motor control

Answer 30

Feedforward and feedback interact to create and adjust movement

Question 31

3 main types of upper extremity impairments of motor control

Answer 31

Perceptual problems

Reach and grasp impairments

Grasp and in-hand manipulation impairments

Question 32

what are perceptual problems with motor control

Answer 32

can be caused by neglect

Difficulty locating target
(visual agnosia)

Difficulty planning and executing reach and grasp

Question 33

what is the Largest contributor to impaired reaching post- stroke

Answer 33

Loss of individuation/development of abnormal synergies

Question 34

what is loss of individuation

Answer 34

Obligatory co-activation of muscles during voluntary motion

stronger in antigravity muscles, usually flexors in upper extremity, extensors in lower extremities

Question 35

what are the 2 potential mechanisms for loss of individuation

Answer 35

Upregulation of extrapyramidal tracts

Cortical reorganization

Question 36

what are 2 Grasp and In-Hand Manipulation Impairments in motor control

Answer 36

Impaired feedforward control and force scaling

increased reliance on feedback

Question 37

If damaged, which of the following structures would MOST affect coordination of movement?

Basal ganglia

Cerebellum

Motor cortex

Premotor cortex

Answer 37

Cerebellum

Question 38

Damage to one side of the cerebellum would result in:

Impaired coordination contralateral to the damage

Impaired strength ipsilateral to the damage

Impaired sensory function ipsilateral to the damage

Impaired coordination ipsilateral to the damage

Answer 38

Impaired coordination ipsilateral to the damage