Week 5 Pt 2 - Control Of Movement Flashcards
1
Q
What are the roles of cerebellum?
A
- Coordinate movement
- Monitor and make corrective adjustments of activities initiated by other parts of the brain
- Maintain balance and posture
- Modulate eye movement
- Motor learning
2
Q
What does the cerebellum not initiate?
A
Movement
3
Q
What does the deep cerebellar nuclei consist of?
A
Fastigial, interposed and dentate nucleus
4
Q
What does the cerebellar peduncles consist of?
A
3 pairs
Connect cerebellum to other parts of the CNS
5
Q
What are the three major functional divisions?
A
- Vestibulocerebellum
- Spinocerebellum
- Cerebrocerebellum
6
Q
Vestibulocerebellum
A
Flocculonodular lobe
7
Q
Spinocerebellum
A
Vermis and paravermal zone
8
Q
Cerebrocerebellum
A
Lateral zones of the cerebellar hemispheres
9
Q
What is inferior cerebellar peduncle?
A
Axons from the spinal cord
Spinocerebellar and cuneocerebellar tract
Connect Medulla to cerebellum
10
Q
What does the major pathway of the inferior cerebellar peduncle form?
A
Contralateral olivary nuclei
11
Q
What is the middle cerebellar peduncle?
A
Axons of pontine nuclei that carry a copy of messages sent down the corticospinal tract
Connect pons to cerebellum
12
Q
What is superior cerebellar peduncle?
A
Main efferent pathway from the cerebellum
Cafes the axons of the deep cerebellar nuclei
Connect the cerebellum to midbrain
13
Q
What does the fastigial nuclei project to?
A
Vestibular nuclei
14
Q
Where does the dentate nucleus project to?
A
Thalamus then to cortex
15
Q
Where does the interposed nuclei project to?
A
Red nucleus
16
Q
What are the afferents of vestibulocerebellum?
A
Arise from vestibular nucleus
Terminate in flocculonodular lobe
17
Q
What do afferents of vestibulocerebellum conduct?
A
Vestibular signals about head position and movements
18
Q
What are the efferents of vestibulocerebellum?
A
From flocculonodular lobe to fastigial nucleus
Vestibular nuclei —> vestibulospibal Tract
Reticular formation in brainstem —> reticulosponal tract
Motor nuclei innervating extraocular muscles
19
Q
What regulates the tone of the antigravity muscles?
A
Vestibulospinal and reticulospibal tract
20
Q
What does the efferents to cranial nuclei regulate?
A
Movement of the eyeballs during head movements to maintain stable vision
21
Q
What is the afferents for spinocerebellum?
A
Posterior (dorsal) Anterior (ventral) Spinal cerebellar tract Cuneocerebellar tract Proprioception input from muscle spindle, Golgi tendon organ, touch/pressure
22
Q
What is the efferent of spinocerebellum?
A
Cerebellocerebral tract via thalamus
Cerebellorubral tract to red nucleus in midbrain
Reticulospinal and rubrospinal tract
23
Q
What modulates the motor neurons in the spinal cord?
A
Reticulospinal and rubrospinal tract
24
Q
What is the afferents of cerebrocerebellum?
A
Originate in the cerebral cortex via pontine nuclei
25
What does the afferents input of cerebrocerebellum carry?
Motor information: the motor commands from motor areas
| Sensory information: the present postural state of the body from the somatic sensory areas
26
What is the efferent input of the cerebrocerebellum?
From cerebellar cortex to dentate nucleus
Through superior peduncle to terminate in VL nucleus of contralateral nucleus
Motor areas of the cerebral cortex
27
What does the cerebello-dentato-thalamo-cerebral pathway mediate?
The role in adjusting the plan of the motor command before being discharged from cerebral cortical motor areas to LMN
28
What is activated when the equilibrium is disturbed?
Vestibular receptors
29
Where does the vestibular receptors signal to?
Vestibulocerebellum to initiate immediate corrective signals
30
Where are the corrective signals sent to?
1. The vestibular nuclei and reticular formation
| 2. The superior colliculus
31
What does the vestibular nuclei and reticular formation do?
Adjust the tone and contractility of the axial and proximal limb muscles
Help maintain equilibrium during change in head position
32
What do superior colliculus do?
Coordinate eye movements with head movements during acceleration
Maintain clear vision
Keep equilibrium during head movements
33
What is the principal region for the postural adjustment?
Vermis
34
Where does the vermis receive sensory information from?
Muscles
Joint proprioceptors
On position of body
35
What does vermis output control?
Vestibulospinal and reticulospinal tract
36
Define coordination of voluntary movements
Ones ability to proceed smoothly and precisely from one movement to the next in proper succession
37
What does the spinocerebellum receive when the motor cortex send commands to spinal cord for a voluntary movement?
Efference copy of the intended motor command through cortico-ponto-cerebellar pathway
38
What happens as the movement proceeds?
The spinocerebellum receives proprioceptive signals about actual motor performance via spinocerebellar tract
39
What does the intermediate zone of the spinocerebellum act as?
Comparator that compares the motor intentions of higher centres with actual performance of muscles
40
What occurs when there is any error in performance or deviation from originial plan?
The intermediate zone and interposed nucleus send corrective signals back to the motor cortex and the red nucleus to correct muscle actions
41
What is the predictive and camping mechanism?
The cerebellum receives information regarding the velocity and direction of the intended movement
42
What does the cerebellum predict?
How far that part of the body will move in a given time
Uses this information to determine the precise time to damp the movement
Sends it’s decision to the motor cortex to stop ongoing movement exactly at the intended position
43
Planning the sequence of movements
The cerebrocerebellum uses information provided from motor cortex and basal ganglia to achieve the goal of the movement
The plan of the movement sequence is transmitted from cerebrocerebellum to motor cortex
Used to adjust the final motor command before it is discharged to LMN
44
Timing of Movements
Cerebrocerebellum provides perfect timing of voluntary movements
Computes the appropriate timing for onset and termination of contraction of each of muscles
45
Define motor learning
A set of internal processes associated with practice or experience leading to relatively permanent changes in the capability for skilled behaviour
46
What is the early stage in motor learning?
When a person first performs a complex motor act the degree of cerebellar adjustment of the onset and termination of the successive muscle contractions involved in movement is almost always inaccurate
Cerebellar neuronal circuit learn to make more accurate movement next time
47
What is intermediate stage in motor learning?
After motor act has been repeated many times (motor training), the successive steps of motor act become gradually more precise
48
What is late stage in motor learning?
Once the cerebellum has perfectly learned its role in different patterns of movement, it establishes a specific “stored programme” for each of the learned movements
49
What is specific signs of cerebellar damage?
1. Ataxia
2. Dysmetria
3. Nystagmus
4. Dysarthria
5. Infection tremor
6. Dysdiadochokinesia
50
What is ataxia?
Lack of voluntary coordination of muscle movements
51
What is dysmetria?
A lack of coordination of movement typified by the undershoot or overshoot of intended position with hand, arm and leg
52
What is Nystagmus?
Flicking eye movements
53
What is dysarthria?
Slurred speech
54
What is Dysdiadochokinesia?
Inaccuracies in rapidly repeated movements
55
What is cerebellum particularly susceptible to?
Effects of alcohol
56
What are central pattern generators?
Microcircuits
Neuronal networks that contain the necessary information to coordinate a specific motor pattern such as breathing, walking and chewing
57
What can CPG be activated by?
Will
| Triggered by sensory stimuli as in a protective reflex or swallowing
58
What is walking produced by?
CPGs in the spinal cord
59
What is chewing movements controlled by?
Brainstem circuits that generate alternating activity between jaw-opener and closer muscles
60
Eye movements
saccadic eye movements
61
What does spinal cord contain?
CPGs for locomotion and protective reflexes
62
What does brainstem contain?
CPGs for breathing, chewing, swallowing and saccadic eye movements
63
What does hypothalamus in the forebrain Contain?
Centres that regulate eating and drinking
64
What can rhythmic patterns be intervened by?
supraspinal commands
65
Where is inspiratory centre located?
Nucleus tractus solitarius
66
What does inspiratory centre emit?
Repetitive burst of inspiratory action potentials
67
How is the basic rhythm of respiration generated?
Mainly by neurons in the DRG
68
Where is ventral respiratory group located?
Nucleus ambiguus rostrally
| Nucleus retroambiguus caudally
69
What does the VRG Contain?
Both inspiratory and expiratory neurons
70
What is the neurons of VRG during normal quiet respiration?
Totally inactive
71
What is VRG responsible for?
Motor control of inspiratory and expiratory muscles during exercise
72
Where is apneustic centre situated?
Lower pons
73
What is the function of Apneustic centre?
Increases depth of inspiration by acting directly on the inspiratory centre
74
What is apneusis?
Abnormal pattern of breathing
| Characterised by deep, gasping inspiration with a pause at full inspiration followed by a brief, insufficient release
75
Where is the pneumotaxic centre situated in?
Upper pons
| Formed by nucleus parabrachialis
76
What is the function of pneumotaxic centre?
Antagonises the apneustic centre
Cyclically inhibits inhalation
The centre limits the burst of action potential in the phrenic nerve
Decreases the tidal volume and regulate the respiratory rate
77
What does an absence of pneumotaxic centre result in?
Increase in depth of respiration
| Decrease in respiratory rate
78
What are motor pools?
The cell bodies of motor neurons arranged in groups in spinal cord and brain stem
79
What does each motor pool activate?
One muscle
80
Where do motor neurons that activate muscles in limbs, torso or neck have their cell bodies in?
Region of spinal cord grey matter - ventral horn
81
What are muscles in the neck and arms activated by?
Motor neurons in cervical spinal cord
82
What are muscles in the chest, legs and pelvic region activated by?
Thoracic, lumbar and sacral spinal cord
83
What is the small bundle of axons called that each motor neuron axon exits the spinal cord?
Ventral root
84
What does the ventral root and dorsal root join to form?
Segmental nerve
85
Where do motor neurons that activate muscles in the head have their cell bodies have their cell bodies in?
Brainstem
| Brainstem: midbrain, pons and Medulla
86
What are motor neurons and the set of muscle fibres it contacts called?
Motor unit
87
What are examples of descending spinal input from brainstem cell groups called?
reticular formation
Vestibular nuclei
The red nucleus
superior colliculus
88
What are the spinal inputs referred to as?
```
Reticulospinal
Vestibulospinal
Rubrospinal
Tectospinal
Corticospinal
```
89
What influences automatic, axial, postural and locomotor movements?
Reticulospinal
Vestibulospinal
Tectospinal
90
What influences voluntary, distal and fine movement control?
Rubrospinal
| Corticospinal axons
91
Where does reticulospinal axon from pons generally project to?
Same side of the spinal cord
92
Where does the reticulospinal axons from Medulla project to?
Both sides of the spinal cord
93
Where are Basal Ganglia and cerebellum locates in?
Basal forebrain
| Hindbrain
94
What is the role of vestibular nucleu?
Mediate vestibuloocular reflex
Head rotation in one direction causes equal and opposition eye rotation
Maintain stable head and body posture during standing and locomotion
95
What is the role of Red nucleus?
Midbrain
| Voluntary control of fingers, hands and arms
96
What is the role of superior colliculus?
Integrate visual, auditory and somatosensory input
Initiate eye and head movement
Command centre for saccade control
97
What is the role of cerebellum?
Found in hindbrain
