PT9111 - LECTURE 15

Question 1

Corticopontocerebellar Pathway

Answer 1

Cerebellum receives input from cortex via the pons (what movement is intended eg. motor plan)

Question 2

Spinocerebellar Pathway

Answer 2

Cerebellum receives position sense input from peripheries of the body (what movement happened)

Question 3

Cerebellothalamocortical Pathway Function

Answer 3

Cerebellum sends out sensory feedback to cortex to correct movement

Question 4

Describe the pathway (anatomical structures) involved in the corticopontocerebllar pathway and their order

Answer 4

Cerebral cortex -> pons -> middle cerebellar peduncle -> purkinje fibers -> deep cerebellar nuclei

Question 5

What 2 outputs do the deep cerebellar nuclei drive

Answer 5

1. Fastigial Output
2. Interposed and Dentate output

Question 6

Fastigial Output

Answer 6

Head, trunk, proximal limb movements; posture, gait and eye movements

Question 7

Interposed and Dentate Output

Answer 7

More distal limb movements ipsilaterally, multi-joint limb movements

Question 8

Describe the spinocerebellar pathway

Answer 8

1. Muscle spindles and/or golgi tendon organs from periphery relay non-conscious proprioception (1st order neuron cell body in dorsal ganglion)
2. 2nd order neuron decussates in peduncle of midbrain and goes to cerebellum (no third order neuron)

Question 9

What are the 4 spinocerebellar pathways and indicate if they are upper/lower extremity and crossed/uncrossed

Answer 9

Lower:
1. Dorsal Spinocerebellar (uncrossed)
2. Ventral Spinocerebellar (crossed)

Upper:
1. Cuneocerebellar (uncrossed)
2. Rostral Spinocerebellar (uncrossed)

Question 10

Describe the pathway of the dorsal spinocerebellar (lower extremity)

Answer 10

1. GTO’s and muscle spindles (1st order neuron) in legs go to spinal cord and terminate in dorsal horn
2. 2nd order neuron originates on ipsilateral dorsal horn and travels up dorsal spinocerebellar tract to medulla and enters the cerebellum via the inferior peduncle

Question 11

Describe the pathway of the ventral spinocerebellar tract (lower extremity)

Answer 11

1. GTO’s to ipsilateral dorsal horn (1st order)
2. 2nd order originates in ipsilateral dorsal horn and decussates and travels to the medulla and the pons via ventral spinocerebellar tract
3. Decussates again in the pons and enters cerebellum via superior peduncle

Question 12

Describe the pathway of the cuneocerebellar tract (upper extremity)

Answer 12

1. Travels from muscle spindles and GTO’s to dorsal horn and ipsilateral to medulla (1st order)
2. 2nd order originates in medulla (accessory cuneate nucleus) and enters ipsilateral cerebellum via inferior peduncle

Question 13

Describe the pathway of the rostral spinocerebellar (upper extremity)

Answer 13

1. GTO’s to ipsilateral dorsal horn (1st order)
2. 2nd order originates in ipsilateral dorsal horn and travels to medulla ipsilaterally and enters cerebellum via inferior peduncle

Question 14

Describe the cerebellothalamocortical pathway

Answer 14

1. Cerebellar Cortex (pukrinje cell)
2. Deep cerebellar nuclei (denate in image)
3. Travels to contralateral thalamus via superior peduncle
4. Then to motor and premotor cortices

Question 15

What does cerebellar lesions impact

Answer 15

Motor learning, ability to produce selective and coordinated movements that include speech, language, and working memory

Question 16

T or F: A lesion to the right side of the cerebellum affects the right side of the body

Answer 16

T

Question 17

Ataxia

Answer 17

Presence of abnormal, uncoordinated movement

Question 18

Dyssynergia

Answer 18

Movement decomposition

Question 19

Dysdiadochokinesia

Answer 19

Difficulty with rapid alternating movements

Question 20

Dysmetria

Answer 20

Undershoots reach to target (hypometria or overshoots (hypermetria)

Question 21

Nystagmus

Answer 21

Involuntary rhythmic eye movements

Question 22

Saccadic Dysmetria

Answer 22

Eye movement under or overshoots target

Question 23

Asthenia

Answer 23

Sense of generalized weakness/heaviness

Question 24

What is an intention tremor

Answer 24

Oscillatory, involuntary muscle contractions during voluntary movement (eg. reaching for a cup)

Question 25

T or F: Cerebellar lesions cause resting tremor

Answer 25

F, they do not

Question 26

Compare normal vs abnormal resting tremor

Answer 26

Normal resting tremor is caused by stress, anxiety, hunger, caffeine and is in the 8-12 Hz rang

Abnormal is caused by Parkinson’s disease and is measured at 3-5Hz

Question 27

Name 3 recovery strategies for cerebellar lesions

Answer 27

1. Aerobic exercise
2. Break movement down (task analysis) and force slow movement to correct movement patterns
3. Start with simple tasks that maximize stability and reduce degrees of freedom of movement (encourage purkinje cell synapsis)

Question 28

What are 3 compensatory strategies for cerebellar lesion treatment

Answer 28

1. Planning and pacing activity (frequent breaks)
2. Visual cues (mirror)
3. Gait aids