pontocerebellum and damage

Question 1

Role of the pontocerebellum

Answer 1

governance of voluntary movement and motor learning

Question 2

pontocerebellum does not receive what?

Answer 2

projections from peripheral receptors

Question 3

Afferent projections to the pontocerebellum originate from where?

Answer 3

in the motor and association corticies of the cerebrum via cortico-pontocerebellar projections

Question 4

Where do cortico-pontocerebellar projections descend from?

Answer 4

motor association cortex likely supplementary and premotor cortex

Question 5

what do cortico-pontocerebellar projections descend through? end on?

Answer 5

internal capsule and medial third of cerebral peduncle to end on neurons of pontine nuclei

Question 6

pontine nuclei axons decussate to enter the cerebellum through what structure?

Answer 6

contralateral middle cerebellar peduncle

Question 7

pontine nuclei rise to the cortex as what type of fibers?

Answer 7

mossy fibers

Question 8

where do mossy fibers end?

Answer 8

on granule cells of the lateral cerebellar cortex

Question 9

where do mossy fiber collaterals end?

Answer 9

on neurons in the dentate nucleus

Question 10

what type of information does cortico-pontocerebellar pathways carry?

Answer 10

information that the cerebellum uses for movement initiation and execution

Question 11

lesions of the corticopontine pathway or pontine nuclei result in what deficits?

Answer 11

contralateral deficits in the arm and leg coordination

Question 12

lesion of the cerebellar peduncle results in what deficits?

Answer 12

ipsilateral deficits in the arm and leg coordination

Question 13

Where does pontocerebellum cortex project to first?

Answer 13

dentate nuclei

Question 14

after the dentate nuclei, where do pontocerebellum cortex project? via what?

Answer 14

via the superior cerebellar peduncle to:
contralateral red nucleus
contralateral VL thalamus

Question 15

Where do dentate projections to the red nucleus end?

Answer 15

on parvocellular neurons which project to the inferior olivary nucleus which then project back into the cerebellum providing regulatory feedback to the cerebellum

Question 16

After dentate projections go to the contralateral VL thalamus, they then project to what? produces?

Answer 16

motor and premotor cortex which produces direct and indirect actions on UMN via corticospinal pathways and corticobulbar pathways

Question 17

Function of the pontocerebellum is in what?

Answer 17

movement initiation

Question 18

when the dentate nucleus was damaged, what functions were lost?

Answer 18

voluntary execution of movement was delayed

Question 19

the known delay of execution of movement after damage to the dentate nucleus suggests what?

Answer 19

that these projections are essential for the initial activation of corticospinal neurons at the beginning of a movement

Question 20

What does damage to the pontocerebellum produce?

Answer 20

a delay of excitatory output from the motor cortex resulting in a corresponding delay in muscle contraction

Question 21

What is lost besides activation of both agonist and antagonist muscle with damage to pontocerebellum?

Answer 21

reciprocal pattern of activation in agonists and antagonists that accompanies many movements

Question 22

What role does the pontocerebellum play in muscle activation?

Answer 22

timing

Question 23

pontocerebellum also influences contraction how?

Answer 23

influences the duration of the muscle contraction

Question 24

damage to the cerebellar cortex alone results in permanent motor damage, true or false?

Answer 24

false.

damage to the cortex rarely results in permanent damage

Question 25

damage to the cortex of the cerebellum AND nuclei or to nuclei alone results in what?

Answer 25

a wide range of motor problems

Question 26

unilateral lesions of the cerebellum result in _______ deficits.

Answer 26

ipsilateral

Question 27

right dentate and interposed nuclei influence what?

Answer 27

the LEFT motor cortex and red nucleus

Question 28

the left motor cortex and red nucleus project to what side of the spinal cord?

Answer 28

right (therefore lesions produce ipsilateral deficits)

Question 29

What do lesions of the lateral cerebellum result in?

Answer 29

deterioration of coordinated movement referred to as movement decomposition or dyssynergia

Question 30

the deficit of dyssynergia consists of what?

Answer 30

the breakdown of movement into its individual component parts

Question 31

dyssynergia s/s?

Answer 31

hypotonia (decrease in muscle tone and in DTRs)

ataxia (uncoordinated limb movement)

Question 32

ataxia with cerebellar damage includes specific symptoms of?

Answer 32

unsteady gait
tendency to lean or fall to the side of the lesion
dysarthria
ocular motor coordination defects
dysmetria- past pointing when pointing at stationary or moving objects

Question 33

What type of tremor is associated with cerebellar damage?

Answer 33

intention tremor

Question 34

what is an awkward performance of rapid alternating movements associated with cerebellar damage?

Answer 34

dysdiadochokinesia

also manifested by inability to perform repeated rhythmic movements

Question 35

What is sensory cerebellar ataxia?

Answer 35

• disruption of proprioceptive afferents
• worsening coordination of movement when eyes are shut
• positive Romberg sign
• problems walking in the dark

Question 36

What is motor cerebellar ataxia?

Answer 36

damage to the cerebellum itself

ataxia symptoms exist with or without vision