Role of cerebellum and basal ganglia in planning and fine control of movement

Question 1

Which 4 types of body orientation are controlled by the cerebellum, which overall allows fine control/coordination of movement?

Answer 1

Movement
Posture
Motor learning
Synergy

Question 2

Define synergy of movement?

Answer 2

Rate/range/force/direction of movement

Question 3

What are the 3 main divisions of the cerebellum?

Answer 3

Vestibulocerebellum

Spinocerebellum

Pontocerebellum

Question 4

What is the other name for the vestibulocerebellum, and which 2 individual cerberllar structures make up the vestibulocerebellum division?

Answer 4

Flocculonodular lobe

Consists of nodule and flocculus

Question 5

Define vestibular input, and how where are vestibular receptors located?

Answer 5

Sensation of any change in position, direction, or movement of the head

Vestibular receptors are located in inner ear

Question 6

What are the 2 effects of the vestibulocerebellum, in terms of controlling movement?

Answer 6

Controls eye movement

Controls balance

Question 7

In the vestiulocerebellum division, which ascending tract is vestibular input transmittted in by first-order sensory neurons from the inner ear vestibular receptors?

Answer 7

Vestibulocerebellar tract

Question 8

In the vestibulocerebellum division, where in the brainstem do most first-order sensory neurons synpase with second-order neurons?

Answer 8

Medial or inferior vestibular nuclei, which are located in the brainstem

Question 9

In the vestibulocerebellum division, how is vestibular input transmitted from the medial/inferior vestibular nuclei in the brainstem to the cerebellar cortex?

Answer 9

Vestibular input continues to ascend from vestibular nuclei, through inferior cerebellar peduncles into cerebellar cortex

Question 10

In the vestibulocerebellum division, do all vestibular inputs ascend to the vestibular nuclei, during transmission to the cerebellar cortex?

Answer 10

No, some first-order neurons ascend directly through inferior cerebellar peduncle to cerebellar cortex

Question 11

Which 2 individual cerebellar structures make up the spinocerebellum?

Answer 11

Vermis (unpaired, middle region of cerebellum that connects both hemispheres)

Intermediate hemispheres

Question 12

Which 2 nuclei (cluster of neurons) are associated with the spinocerebellum?

Answer 12

Interposed nuclei

Fastigial nuclei

Question 13

What are the 2 effects of spinocerebellum division, in terms of controlling movement?

Answer 13

Recieves spinal cord input to:

Control synergy of movement

Convey proprioceptive info (ability to sense movement, action, and locate body parts), touch, pressure

Question 14

What are the 2 ascending tracts to the spinocerebellum division?

Answer 14

Posterior/dorsal spinocerebellar tract

Anterior/ventral spinocerebellar tract

Question 15

Which spinal segmental levels detect spinal cord input that ascends through the posterior/dorsal spinocerebellar tract, and which body regions are supplied by the output?

Answer 15

Segments above L3 level

Trunk, lower limbs

Question 16

Which spinal segmental levels detect spinal cord input that ascends through the anterior/ventral spinocerebellar tract, and which body regions are supplied by the output?

Answer 16

Segments below L3 level to coccygeal

Lower limbs

Question 17

In the spinocerebellar tracts, which 3 structures detect proprioceptive, touch and pressure input?

Answer 17

Muscle spindles

golgi tendon organ

pressure receptors

Question 18

In the spinocerebellar tracts, where in the spinal cord do first-order sensory neurons transmit proprioceptive, touch and pressure input to?

Answer 18

Input carried past dorsal root ganglion, into dorsal horn/posterior grey column

First synaptic site is in the posterior grey column

Question 19

In the spinocerebellar tracts, which specific second-order neurons do first-order sensory neurons synapse with in the posterior grey horn?

Answer 19

First-order neurons synapse with second-order neurons of Clark’s nucleus

Clark’s nucleus/Column of Clarke: Column of interneurons found within rex lamina (7), which have nuclei ranging from C8-L3 levels

Question 20

Where do the axons of the second-order neurons from Clarke’s nucleus travel to from the posterior grey column before starting to ascend, in the 2 spinocerebellar tracts?

Answer 20

Posterior/dorsal tract: Axons enter lateral white column and move ipsilaterally (affects same side of body) towards posterior region

Anterior/ventral tract: Axons move contralaterally (to opposite side of body) across midline of spinal cord to lateral white column, which is on opposite side from where neurons entered spinal cord

Question 21

Does the axon of the second-order neuron from Clarke’s nucleus ascend ipsilaterally or contralaterally to the side where the input entered the spinal cord, in the posterior spinocerebellar tract?

Answer 21

Second-order neuron ascends ipsilaterally (still on same side of body)

Question 22

Does the axon of the second-order neuron from Clarke’s nucleus ascend ipsilaterally or contralaterally to the side where the input entered the spinal cord, in the anterior spinocerebellar tract?

Answer 22

Second-order neuron ascends contralaterally

Question 23

In the anterior spinocerebellar tract, which cerebellar peduncle does the axon of the second-order neuron enter to reach the ipsilateral side of the cerebellum (same side that first-order neurons entered spinal cord)?

Answer 23

Enters superior cerebellar peduncle to enter cerebellum

Crosses midline again to reach other side of cerebellum (which is on same side that first-order neurons entered spinal cord)

Question 24

In the posterior spinocerebellar tract, which cerebellar peduncle does the axon of the second-order neuron enter to reach the ipsilateral side of the cerebellum (same side that first-order neurons entered spinal cord)?

Answer 24

Enters inferior cerebellar peduncle

Question 25

Overall, do both of the spinocerebellar tracts supply the ipsilateral cerebellar cortex (on same side that first-order neurons entered spinal cord)?

Answer 25

Yes

Question 26

In the spinocerebellar tracts, where does the second-order neuron of Clarke's nucleus synapse, after ascending to the cerebellar cortex?

Answer 26

Synapses with third-order neurons of cerebellar cortex

Question 27

Which cerebellar structure makes up the pontocerebellum/ cerebrocerebellum division, and what type of nuclei is found in this division?

Answer 27

Lateral hemispheres Dentate nuclei (cluster of neurons with serrated/dentated edge)

Question 28

Where does the pontocerebellum/ cerebrocerebellum receive sensory input from, and what is its effect on movement?

Answer 28

Cerebral cortex Controls planning/initiation of movement of extremities

Question 29

In the pontocerebellar tract, where do first-order neurons from the cerebral cortex synapse with second-order neurons?

Answer 29

Synapse with second-order neurons in the pontine nuclei

Question 30

In the pontocerebellar tract, how do axons of second-order neurons in the pontine nuclei reach the contralateral cerebellar cortex?

Answer 30

Axons of pontine nuclei ascend through middle cerebral peduncle to supply contralateral cerebellar cortex

Question 31

Define cerebellar peduncle?

Answer 31

Structure connecting brainstem and cerebrum to cerebellum Superior, middle, inferior

Question 32

Define cerebellar cortex?

Answer 32

Continuous 3-layered sheet of neurons that is the outer layer of the cerebellum, that receives input from rest of body and brain regions to be integrated by the cerebellum, which sends output to rest of brain

Question 33

Where is the basal ganglia located, and what are its 4 primary associations with movement?

Answer 33

Basal ganglia: Group of subcortical nuclei located deep in core of each cerebral hemisphere Motor control and learning, executive function, behaviours, emotions

Question 34

How does the indirect pathway of the basal ganglia inhibit undesired movement?

Answer 34

Causes inhibition of VL nucleus of the thalamus so that excitatory projections aren’t sent to the motor cortex

Question 35

How does the direct pathway of the basal ganglia promote desired movement?

Answer 35

Excitatory pathway of desired movement, as is causes inhibition of inhibitory region within thalamus, which causes disinhibition