Lecture 11: Central Control of Movement Flashcards
1
Q
What structures make up the forebrain
A
Cerebrum, thalamus and hypothalamus
2
Q
What is the major relay center of the brain, master controller
A
Thalamus and hypothalamus
3
Q
What structure in the CNS links the brain stem and cerebrum with ascending and descending fibers. Contains visual and auditory relay circuits
A
Midbrain
4
Q
What structure in the CNS is derived from neural tube during development
A
Pons and cerebellum
5
Q
What structure in the CNS contains fiber tracts and relays between cerebellum and cerebrum
A
Pons
6
Q
What is the suprasegmental structure in the brain stem
A
Cerebellum
7
Q
What structure in the CNS contains fiber tracts that relay circuits that control breathing, HR, and visceral function
A
Medulla oblongata
8
Q
Describe the flow of information through the brain
A
- Information flows from sensory neurons to
- Primary sensory cortex to
- Sensory association cortex to
- Multimodal association cortices to
- Premotor cortex to
- Primary motor cortex
9
Q
What does the multimodal association cortices do
A
Gives meaning to information, stores information in memory, decision making areas
10
Q
The multimodal association cortices relays decisions to ___
A
Premotor cortex
11
Q
What cortex results in movement and action
A
Primary motor cortex
12
Q
What are three other important brain circuits send information to the cortex
A
- Basal nuclei and cerebellum
- Limbic system
- Reticular activating network
13
Q
What is the function of the parietal lobe
A
Auditory processing
14
Q
What is the function of the occipital lobe
A
Visual processing
15
Q
What is the function of the temporal lobe
A
Auditory processing and memory
16
Q
What is the function of the motor cortex
A
Motor processing, decision making, mood
17
Q
What are the three regions of the motor cortex
A
- Premotor
- Supplementary motor
- Primary motor
18
Q
Neurons in the ____ and ___ motor areas are linked to primary motor cortex
A
Premotor and supplementary motor
19
Q
What is the motor homunculus
A
Map of body on the cortex, meaning nearby neurons have similar function
20
Q
UMN and LMN connect cortex to ____
A
Target muscles
21
Q
UMN start in motor cortex and reach LMN via the ___ or ___ tracts
A
Corticospinal or corticobulbar
22
Q
What pathway has UMN terminate in the brain stem
A
Corticobulbar pathway
23
Q
What pathway has UMN terminate in the spinal cord
A
Corticospinal pathway
24
Q
CN I- name and function
A
Olfactory- smell
25
CN II- name and function
Optic- vision
26
CN III name and function
Oculomotor- eyeball and eyelid movement, pupil contradiction, focus of the lens
27
CN IV- name and function
Trochlear- eyeball movement and proprioception
28
CN V name and function
Trigeminal- chewing, somatic sensations of the face and mouth
29
CN VI name and function
Abducens-eyeball movement and proprioception
30
CN VII name and function
Facial- facial expression, secretion of saliva and tears, taste from front of tongue
31
CN VIII name and function
Vestibulocochlear- hearing and equilibrium
32
CN IX name and function
Glossopharyngeal- swallowing and secretion of saliva. Taste from back of tongue, somatic sensation in mouth
33
CN X name and function
Vagus efferent output for skeletal muscles of pharynx and larynx. PNS smooth muscles and glands of abdominal cavity. Cardiac regulation. Afferent input from thoracic and abdominal organs, blood pressure monitoring
34
CN XI name and function
Accessory- efferent output for skeletal muscles of the pharynx, larynx, neck and shoulder
35
CN XII name and function
Hypoglossal- tongue movement
36
Describe the corticobulbar tract
1. UMN arise from lateral primary motor cortex
2. Synapse on LMN in brain stem
3. LMN run through cranial nerves and determine motor control of head and neck
37
Which cranial nerves are LMN
III- VII, XI- XIII
38
Which cranial nerves are tested in pupillary light reflex
II and III
39
Which of the two, CN II or CN III is efferent
CN II- afferent
CN III= efferent
40
Where do UMN decussate in the corticospinal tract
Caudal end of medulla
41
90% of UMN in corticospinal tract do what
Decussate- Cross the midline to enter the spinal cord on opposite side
42
10% of UMN in corticospinal tract do what
Continue down spinal cord without crossing
43
LMN are ___motorneurons that innervate skeletal muscles
Alpha-motor neurons
44
LMN from the lateral part of the ventral horn innervate ___
Muscles of distal limbs
45
LMN from the medial part of the ventral horn innervate ___
Axial muscles and muscles of the proximal limbs
46
Where are neurons in the extrapryamidal system located
Neurons are located in the nuclei of the brain stem:
1. Red nucleus
2. Reticular formation
3. Vestibular nucleus
4. Tectum
47
Damage to the extrapyramidal tracts is associated with ___ and ___ pathology
Hypertonic and hypotonic pathology
48
What is decerebrate rigidity
Condition of increased muscle tone and stretch reflexes, particularly the extensor muscles resulting in extensor hypertonia
*absence of flexor muscle activity
49
What is opsithotonus
Spasm of muscles causing backward arching of head and neck
50
What extrapyramidal dysfunction occurs is the decerebrate rigidity (commonly a result of HBC)
Damage to red nucleus—>rubrospinal tract
51
What extrapyramidal neurons receive information from motor cortices
Red and reticular
52
What extrapyramidal neurons receive information from sensory organs in head
Superior and vestibular nuclei
53
The red nucleus receives input from….
Motor cortex and cerebellum
54
rubrospinal tract neurons provide excitation to LMN that control ___muscles in neck and proximal limbs, but inhibit ____muscles in limbs
Excite flexors, inhibit extensors
55
Is the rubrospinal activation voluntary or involuntary
Involuntary
56
Damage to the rubrospinal tract causes extensor ___
Extensor hypertonian(can’t provide inhibition to extensors and can’t activate flexors so get excessive extension of limbs)
57
Is the reticulospinal tract voluntary or involuntary
Involuntary extensor and flexor control
58
What is the pontine reticulospinal tract
Neurons excite alpha and gamma neurons to extensor muscles
59
What is the medullar reticulospinal tract
Neurons inhibit pontine tract, therefore inhibit extensor muscles
60
The reticulospinal tract allows for balance in descending influences onto ___ and ___ muscles and ___co-activation
Balance extensor and flexors
Alpha-gamma co-activation
61
Lesions to the reticulospinal tract will decrease ___ control
Postural
62
Injury to excitatory fibers of the reticular formation can result in ___
Hypotonia (flaccidity)
63
Injury to inhibitory fibers of the reticular formation can result in ___
Hypertonia (spasticity)
64
Where does the vestibular nucleus receive information from
Vestibular apparatus of the inner ear and cerebellum
65
The vestibulospinal tract controls __
Body position and balance
66
Damage to the vestibulospinal tract causes ___
Hypotonia
67
The tectospinal tract (superior/rostral colliculus) receive input about ___
Visual, auditory and somatosensory inputs about environmental stimuli
68
The tectospinal tract is involved in reflex orientation of ____ and ___ towards environmental stimuli
Head and eyes
69
The tectospinal tract controls the ___ and ___ musculature of the head
Axial and proximal
70
Damage to the tectospinal tract results in
Inability to orient head towards and fix gaze on an object
71
Do UMN in pyramidal tract transfer voluntary or involuntary motor action
Voluntary
72
Which tract exert control on LMN to increase fine control
Extrapyramidal tracts
73
Damage to ___ can cause inability to move, inappropriate movements (hyperreflexia), increased muscle tone and possible muscle atrophy
UMN
74
Damage to __ can cause inappropriate or absence of movement, hyporreflexia, flaccid muscles, paraplegia, muscle atrophy and reduced muscle tone
LMN
75
In feline diabetic neuropathy are LMN or UMN affected
LMN
76
LMN neuropathy occurs in feline diabetics because….
Axons die due to lack of delivery of metabolites
*longest axons most susceptible
77
What is muscle tone
Refers to resting level of tension in the muscle
78
Appropriate muscle tone allows muscle to…
Respond to nerve commands, maintaining posture and activity
79
Muscle tone is a result of resting level of discharge of ___motor neurons
Alpha
80
What is the major regulator of alpha motor neurons in maintaining muscle tone
Afferent muscle spindles
81
What is the role of alpha-gamma co-activation in muscle tone
Gamma efferent system regulates the resting level of activity in spindle afferents and establishes baseline level of alpha motor neuron activity in absence of muscle stretch
82
Reduced muscle tone is a result of damage to
Alpha-motor neuron (LMN)
83
Increased muscle tone is a result of damage to
UMN, lesion disturbs balance of supraspinal inhibitory and excitatory producing state of net disinhibition
84
Decerebrate rigidity is a result of trauma/lesion to where
Head trauma, specifically lesion to midbrain
85
In relation to other structures in the brain where is the damage located in decerebrate rigidity (above and below what structures)
Above the pons, medulla and vestibular nuclei, below the red nucleus
86
Where do pyramidal tracts descend from
Spinal cord or brain stem (corticospinal and corticobulbar)
87
__% of corticospinal tracts decussate in medulla and __% cross in the spinal cord
90%, 10%
88
What is the function of the lateral pyramidal tract
Fine movement
89
What is the function of the ventral pyramidal tract
Postural movement
90
Where do the extrapyramidal tracts originate
Brain stem nuclei
91
All of the extrapyramidal tracts cross to the Contralateral side except ___
Vestibulospinal
92
What are the functions of the vestibulospinal tract
Body posture, involuntary movements, modulation
93
What are the reflexes like in damage to UMN
Hyperreflexia
94
What is the atrophy like in patients with UMN damage
Late and mild
95
What is the tone like in patients with UMN damange
Weakness, spasticity, increased tone, loss of fine voluntary movement
96
Where is the location of UMN syndrome
Brain, C1-C5, T3-L3
97
What are the reflexes like in LMN syndrome
Hyporreflexia
98
What is the atrophy like in LMN syndrome
Rapid and severe
99
What is the tone like in patient with LMN syndrome
Weakness, paralysis, decreased tone, fasciculations, and fibrillations
100
Where is the location of LMN syndrome
C6-T2, L4-S3
