Motor Control 3

Question 1

what are the 3 lobes of the cerebellum

Answer 1

anterior, posterior, flocculonodular

Question 2

which lobe is the vestibulocerebellum part of

Answer 2

flocculonodular

Question 3

what is the function of the flocculonodular lobe

Answer 3

balance and posture

Question 4

what is the name for the middle part of the cerebellum

Answer 4

vermis (worm)

Question 5

what are the principle afferents of the cerebellum

Answer 5

pre and primary motor cortex and somatosensory cortex via
pontine nuclei & middle
peduncle

Reticular nuclei
& Olives via inferior
peduncle

Vestibular nuclei via inferior
peduncle

Dorsal (via inferior peduncle) and ventral (via
superior peduncle) ascending spinal
proprioception

Question 6

what is the function of the flocculonodular lobe

Answer 6

maintains balance and posture

Question 7

what is the function of the spinocerebellum

Answer 7

modulates axial/ antigravity muscles and eye movement

Question 8

whatis the function of the cerebrocerebellum

Answer 8

motor planning and feeds information towards the cerebrum
sequence and coordinate distal muscles esp. during locomotion or
juggling etc.

Question 9

what is the input to the cerebrocerebellum

Answer 9

motor and premotor cortices and somatosensory cortex via multiple pontine nuclei

Question 10

what is the spinocerebellum input

Answer 10

ascending sensory spinal pathways derived principally from proprioceptors to the spinocerebellum

contains a somatotopical map of the body

Question 11

what is the input to the vestibulocerebellum

Answer 11

vestibular nuclei

Question 12

what mnemonic can be used to remember cerebellar output

Answer 12

lat to med

don’t eat greasy food

dentate nucleus
emboliform nucleus
globose nucleus
fastigial nucleus

Question 13

what is the target of the rostral fastigial nucleus

Answer 13

medial descending systems

(trunk and proximal muscles via reticular formation)

motor execution

Question 14

what is the target of the interposed nucleus

Answer 14

lateral descending systems

(distal and extremities via spindles)

motor execution

Question 15

what is the target area of the dentate nucleus

Answer 15

motor and premotor cortices

motor planning function

Question 16

what is the target of the caudal fastigial nucleus

Answer 16

vestibular nuclei, tectum, cranial nerve nuclei

head and eye movements

Question 17

how does the cerebellum modulate motor output

Answer 17

integration of activity in pre motor and motor areas plus spinal motor circuits

and sensory feedback from vestibular system, visual system, ascending proprioceptive information

Question 18

where is modulation by the cerebellum effected

Answer 18

motor cortex and brainstem

Question 19

where does information from the vestibular apparatus go

Answer 19

passed to the flocculonodular lobe, vermal and paravermal areas

Question 20

what is the function of the olivary information

Answer 20

enables calculation of predicted posture in advance of it happening, so feed forward posture allows fast postural changes

Question 21

what is Flocculonodular lobe syndrome

Answer 21

seen in children with medulloblastoma

truncal ataxia, wide based stance and swaying

Question 22

how does proprioceptive information arrive at the spinocerebellum

Answer 22

via spinocerebellar and cuneocerebellar tracts

Question 23

where is motor intention information to the spinocerebellum sent from

Answer 23

motor cortex

Question 24

what movement does the spinocerebellum modulate

Answer 24

truncal and UL and fingers

Question 25

how does the spinocerebellum work

Answer 25

planned and actual motor output are compared and corrective signals are sent via the thalamus to the cerebra and red nucleus and vestibular nuclei

Question 26

what is anterior lobe syndrome

Answer 26

errors with the spinocerebellum overshoot, intention tremous and lack of movement damping

Question 27

how does information arrive at the cerebrocerebellum

Answer 27

cortex via pontine nuclei

Question 28

describe the pathway for output from the cerebrocerebellum concerning the order and timing of movements

Answer 28

routed through the dentate nucleus and back via the thalamus to the cortex

Question 29

what are the functions of the cerebrocerebellum

Answer 29

sequencing and timing of complex movements also to predict the movement of objects or the movement of oneself in relation to objects

Question 30

what is the result of medial cerebellar lesions

Answer 30

medial descending pathways affected unsteady gait; truncal ataxia, problems with balance, posture and eye movement abnormalities (nystagmus)

Question 31

how does information arrive at the cerebrocerebellum

Answer 31

cortex via pontine nuclei

Question 32

why are medial lesions to the vermis bilateral (trunk and proximal muscles)

Answer 32

the medial motor system innervation is bilateral

Question 33

what is the effect of lateral cerebellar lesions

Answer 33

affect control of distal muscles, motor planning (areas of the cerebellum that control muscles of extremities) results in limb ataxia

Question 34

what is the effect of lesions of the cerebrocerebellum

Answer 34

delay in initiation of movement | decomposition of multijoint movements (loss of complex motor skills)

Question 35

why do unilateral cerebellar lesions give ipsilateral effects

Answer 35

output from the cerebellum is contralateral to the motor centres which then cross back at the pyramids (double cross)

Question 36

why are medial lesions to the vermis bilateral (trunk and proximal muscles)

Answer 36

the medial motor system innervation is bilateral

Question 37

what is the effect of lateral cerebellar lesions

Answer 37

affect control of distal muscles, motor planning (areas of the cerebellum that control muscles of extremities) results in limb ataxia

Question 38

what is the effect of lesions of the cerebrocerebellum

Answer 38

delay in initiation of movement | decomposition of multijoint movements (loss of complex motor skills)

Question 39

what is the effect of lesions in the vermis (spinocerebellum)

Answer 39

axial and trunk muscles affected so makes balance unsteady- wide stance slowed and slurred speech

Question 40

what is the effect of lesions of the intermediate lobe (spinocerebellum)

Answer 40

distal muscles affected and limb ataxia and action tremour

Question 41

what are the five subcortical structures of the basal ganglia

Answer 41

``` caudate nucleus (includes nucleus accumbens) putamen globus pallidus subthalamic nucleus substantia nigra ```

Question 42

what is the neostriatum made up of

Answer 42

caudate nuclues and putamen

Question 43

what is the function of the basal ganglia

Answer 43

refinement and initiation of motor output and the emotial and reward aspects of motor output (limbic loop) behavioural and learning influence can initiate movement

Question 44

what can basal ganglia lesions cause

Answer 44

problems 'getting going'

Question 45

what is the collective name for the putamen and the cordate nucleus

Answer 45

neostriatum

Question 46

describe the accelerator direct pathway | in which the medial GP acts as a brake to movement

Answer 46

cerebral cortex excites the neostriatum with glutamate neostriatum inhibits the GP medial lobe with GABA the medial lobe usually inhibits the thalamus Increased activity at the thalamus results in increased cerebral stimulation and so, increased movement

Question 47

describe the Indirect pathway ‘The brake’: In which the medial G. Pallidus also acts like a brake

Answer 47

1. Cerebral cortex excites the neostriatum with glutamate 2. Neostriatum inhibits the Globus Pallidus lateral lobe with GABA 3. The lateral lobe normally inhibits the subthalamic nucleus (GABA) but as it is inhibited, the subthalamic nucleus activity rises 4. The subthalamic nucleus then increases its normal excitation of the medial lobe of the Globus Pallidus which increases its activity 5. Increased activity at medial lobe (brake to movement) results in increased inhibition of the thalamus and so a reduction in cerebral stimulation . 6. This in turn results in reduced movement

Question 48

what are the two parts of the substantia nigra

Answer 48

pars reticularis | pars compacta

Question 49

what is parkinsons disease

Answer 49

progressive degeneration of the dopaminergic neurones of the substantia nigra loss of dopamine leads to hypokinesia

Question 50

how does parkinsons disease cause hypokinesia

Answer 50

a decrease in the direct pathway activity an increase in the indirect pathway activity

Question 51

what are the characteristics of parkinsons disease

Answer 51

``` bradykinesia difficulty initiating movement (akinesia) increased muscle tone tremour of the hands and jaw at rest cognitive impairement ```

Question 52

what are the features of huntingtons disease

Answer 52

heritable mutation resuting in malformed protein loss of encephalinergic and GABAergic neurons in the neostriatum (caudate nucleus) leading to a decrease in the activity of the indirect pathway

Question 53

what are the characteristics of huntingtons disease

Answer 53

wildly flailing limbs and contorted posture reduced ability to saccade (movement of the eye between two fixed points) abnormal emotional responses reduced cognitive ability

Question 54

when does Huntingtons normally occur

Answer 54

50s | life expectancy is 15 years after diagnosis

Question 55

how is tourettes related to the basal ganglia

Answer 55

believed to be a hyperkinetic disease of the basal ganglia