Motor Flashcards
1
Q
How does movement start?
A
- Decision made in anterior frontal lobe of cerebral cortex
- Activation of motor planning areas
- Control areas (basal ganglia and cerebellum
- Descending tracts (upper motor neurons)
- Spinal interneurons
- Lower motor neurons
- Skeletal muscles (contraction)
2
Q
What is the motor control hierarchy?
A
- cerebral cortex
- brainstem
- some UMNs go to segmental (interneurons)
- Lower motor neurons
3
Q
What are the sites for upper motor neurons?
A
- Cerebral cortex
2. Brainstem
4
Q
What are the sites for lower motor neurons?
A
- Brain stem
2. spinal cord
5
Q
What are motor control areas?
A
- Basal ganglia
2. Cerebellum
6
Q
What are the three types of motor injuries?
A
- UMN injury
- LMN injury
- Basal ganglia/ cerebellar injury
7
Q
What is the result of a lower motor neuron injury?
A
Inability for the muscle to contract
- flacidity
- loss or decrease of reflex
8
Q
Basal ganglia and cerebellum always connect to ______. A muscle always connects to ______.
A
UMN; LMN
9
Q
Resistance to stretch
A
Tone
10
Q
Where are LMN located?
A
- Ventral horn of spinal cord
2. Brain stem
11
Q
Where do LMN of ventral horn of the spinal cord go to?
A
Body
12
Q
Where do LMN of brain stem go to?
A
head, face, a little bit of the neck
-cranial nerves
13
Q
What do alpha motor neurons innervate? gamma motor?
A
- Go to extrafusal muscle fibers to produce contraction
- Go to Intrafusal muscle fibers to maintain sensitivity to muscle spindes
14
Q
What type of synapse is at the motor neuron? what is the neurotransmitter? What type of receptor?
A
NMJ; ACh; Nicotinic
15
Q
One alpha motor neuron and all of the m fibers it supplies
A
Motor unit
16
Q
Where do medial ventral horns neuron innervate? lateral ventral horns?
A
Proximal extremities; Distal extremities
17
Q
What are the components of a spinal reflex?
A
- Sensory neuron bringing info in
- Interneuron (possible, but can sometimes be exempt)
- Motor neuron to produce reflex
- may just have 1 and 3 depending on the reflex
18
Q
Receptor that responds when a muscle is being lengthened and when its being held in a lengthened position
A
Muscle spindle
19
Q
What determines if a a motor unit is slow twitch or fast twitch?
A
the alpha motor neuron
20
Q
Name the following characteristics that correlates with slow twitch muscles:
- Alpha motor neuron diameter
- M.’s innervated
- Recruitment order
- Speed generation
- Sources of energy
- Fatigue
A
- Smaller
- Postural
- first
- slow
- Aerobic
- Resistant
21
Q
Name the following characteristics that correlates with fast twitch muscles:
- Alpha motor neuron diameter
- M.’s innervated
- Recruitment order
- Speed generation
- Sources of energy
- Fatigue
A
- Larger
- Movement
- Later (we need more force)
- Fast
- Anaerobic
- Sensitive
22
Q
Receptor that responds to Tendon tension by passive stretching or active contraction
A
GTO
23
Q
Sensory receptor that responds to noxious stimuli
A
Cutaneous receptor
24
Q
Muscle spindle reflex:
- Dynamic, deep tendon
- Stimulus = stretchING (lengthening a muscle)
- Response = muscle contraction
A
Phasic stretch reflex
25
Muscle spindle reflex:
- Stimulus – stretch of a muscle (keeping a muscle in a lengthened position)
- Response = increase the likelihood of a m contraction or force of contraction
Tonic stretch reflex
26
Are there inter neurons in the phasic stretch reflex?
No
| - no interneuron needed because it is coming in and going out of same neuron
27
Are there interneurons in the tonic stretch reflex?
Yes
| - Multisynaptic reflex = two or more synapses going out from the sensory neuron
28
Are there interneurons in the GTO reflex?
Yes
- Increased contraction results in inhibition of the contraction to reduce risk of muscle injury
- Also thought to play a role in motor recruitment to prevent using the same motor neurons every time a contraction happens, reducing risk of fatigue
29
Withdrawal reflexes; Respond to nociceptive input
Cutaneous reflexes
30
Where are UMNs located? where do they project to?
- Cerebral Cortex and Brainstem
| - LMN in brainstem and spinal cord
31
Pathway to spinal cord:
- Synapse in medial ventral horn
- Muscles for proximal m’s (axial and proximal joint m's)
Medial activating systems
32
Pathway to spinal cord:
| Synapse in lateral ventral horn; Muscles for distal extemities
Lateral activating systems
33
Pathway to spinal cord:
| Synapse throughout ventral horn; Control level of activity
Non-specific activating systems
34
What are the 5 medial systems tracts?
1. Ventral (medial) corticospinal
2. Medial vestibulospinal
3. Lateral vestibulospina
4. Medial reticulospinal
5. Tectospinal
35
Involved in trunk axial, and girdle movements; More involved with medial systems; Some role in planning movements
Premotor cortex
36
Involved in sequential movements (i.e., throwing a ball); Bimanual movements (movements on both sides of the body), coordinating movements on both sides (i.e., holding something with one hand while manipulating something with the other hand)
Supplementary motor cortex
37
What neurotransmitter is used in the raphespinal tract? cerulospinal tract?
Serotonin; NE
38
Control upper motor neuron system; adjust activity in descending motor tracts
DO NOT have direct connections with lower motor neurons
Basal ganglia and cerebellum
39
Where are the basal ganglia located?
1. Cerebrum - caudate, putamen, globus pallidus (internus, externus)
2. Diencephalon - sub thalamic nucleus
3. Midbrain - substantial nigra (pars compact, pars reticulata)
40
What basal ganglia are input areas?
1. Caudate (psychological factors)
| 2. Putamen
41
What basal ganglia are processing areas?
1. Globus pallidus externus
| 2. Subthalamic nucleus
42
What basal ganglia are output areas?
1. Globus pallidus internus
| 2. Pars reticulata
43
What basal ganglia is responsible for making dopamine and is a regulatory region?
Pars compacta
44
What basal ganglia is referred to as "striatum"
Caudate and putamen
45
What basal ganglia is referred to as the lenticular nucleus?
GPi, GPe, and putamen
46
What BG pathway facilitates the lateral pathways and inhibits medial pathways?
Direct pathway
47
What BG pathway facilitates medial pathways and inhibits lateral pathways?
Indirect pathways
48
The direct pathway receives input information in the _____. It processes information in the _____. It then goes to output nuclei located in the ____, then to the _____. The information either goes to the ______ to [excite/inhibit] the lateral systems OR goes to the ____ to [excite/inhibit] the medial systems.
Putamen; GPe; GPi; substantia niagra reticulata; motor thalamus; excite; pedunculopontine nucleus; inhibit
49
The indirect pathway receives input information in the _____. It processes information in the _____ and the ______. It's output nuclei are located in the ____ or the _____. The information either goes to the motor thalamus to [excite/inhibit] the lateral systems OR goes to the pedunculopontine nucleus to [excite/inhibit] the medial systems.
Putamen; GPe, subthalamic nucleus; GPi, substantia niagra reticulata; inhibit; excite
50
Dopamine increase moves things in the brain towards the [direct/ indirect] pathway or facilitates the [medial/ lateral] systems
direct; lateral
51
What are the functions of the basal ganglia?
1. Sequencing movements
2. Regulating muscle tone and force
3. Selecting synergies (direct pathway) and inhibiting synergies (indirect pathway)
4. Motor learning
52
What is a hypokinetic BG disorder? what are the hyperkinetic BG disorders?
Parkinson's disease;
1. Huntington's disease
2. Dystonias
3. Choreoathetotic CP
4. Hemiballismus
53
Most common BG disorder; Unknown cause; for onset of disease; Neurodegenerative disease with unknown cause of dopamine production decrease
Parkinson's disease
54
What is the result of PD's dopamine production decrease? (etiology and symptoms)
- dopanuergic neurons dying due to low dopamine; getting down to 15 - 20% of these neurons result in symptoms of parkinson disease; results in Increase in activity of indirect pathways - Facilitates medial systems
Sx:
1. Akinesia – difficulty initiating movements
2. Bradykinesia - slow movements
3. Tend to have a tremor at rest (“pill rolling” tremor)
55
Someone loses dopanuergic neurons and devolops symptoms of parkinson’s disease but you DO know what the cause (event or drug); i.e., Muhammad Ali had disease due to getting hit in the head, Synthetic opiate drug, and Drugs used to treat Schizophrenia
Parkinsonism and parkinsonian syndrome
56
Basal ganglia and cerebral cortex damage involved; Increase in involuntary movements; Pts also develop dementia
Huntington's Disease
57
Genetic movement disorder; Dysfunction in basal ganglia; Usually non-progressive; Involuntary sustained muscle contractions; Twisting or repetitive motions or abnormal posture
Dystonia
58
What are the most common types of dystonias?
Focal dystonias
| - affects just one part of the body, often limited to a particular activity
59
What is the focal dystonia where deteriation in handwriting due to involuntary muscle contractions in upper limb? What is the focal dystonia where the 4th and 5th fingers flex involuntarily?
Writer's cramp; musician's cramp
60
Damage to BG structures that results in rapid involuntary movements and slow writing movements
Choreoathetotic CP
- Chorea = "dance"; rapid movements
- Athetotic = slow writhing
61
Damage to sub thalamic nuclear that results in ballistic movements (Proximal part of the extremity moves and the rest of the extremity goes along with it) on the contralateral side
Hemiballismus
62
Where is the cerebellum located and what are its functions?
```
- posterior to the braistem (pons and medulla)
Functions:
1. Balance
2. Coordination
3. Eye movement
```
63
Where are the deep cerebellar nuclei located? what is its function?
embedded in the white matter (FYI gray matter is outer and white matter arbor vita is deep to it)
- output region
64
What are the gyri/sulci of the cerebellum referred to as?
folia (means leaf)
65
Where are the interneurons of the Cb located? where are Purkinje cell bodies located?
outer and inner layers of the Cb; middle layer
66
Where do Purkinje cells project to?
1. deep cerebellar nuclei
| 2. vestibular nuclei (in brainstem)
67
What lobe of the Cb is its own part?
Flocculonodular (lateral parts are flocculus and middle is nocullus)
- anterior and posterior lobes are together as one, contains the vermal, paravermal, and lateral regions
68
Where does afferent (input) information from the SC and brainstem enter the Cb?
Inferior cerebellar peduncles
| - connect btwn Cb and medulla
69
Where does afferent (input) information from the pons enter the Cb?
Middle Cb peduncles
- largest of the peduncles
- The pathway is motor cortex to the base of the pons. These axons synapse on neurons in the base of the pons. These neurons send their axons which cross the midline of the pons and enter the Cb through the middle cerebellar peduncle
- AKA corticalpontine fiber, travel with corticospinal pathways
70
Where does efferent information (output) exit the Cb and where does it go to?
Superior Cb peduncles
| - connects with red nucleus in the midbrain
71
What part of the Cb controls fine movement? what is the name of the tract?
Lateral hemispheres
| - cerebrocerebellum (controls distal parts of the extremities, like hands, therefore fine movement)
72
What are the functions of the cerebrocerebellar tract?
1. Control of distal limb movements
2. Planning of movements, particularly learned, skilled movements
3. Coordination of movements
4. Ability to judge time intervals and produce accurate rhythms
73
What region of the body does the vermal region of the Cb control? Paravermal?
- Trunk
| - Limbs
74
Where does the vermal region of the Cb get input from?
1. Spinal cord from trunk
2. Vestibular nuclei
3. Auditory and vestibular information through brainstem nuclei
75
Where does info from the vermal region go to?
1. Vestibular and Reticular N (Balanance, coordination, extension)
2. Motor Cortex
76
What are the vermal region of the Cb functions?
1. Postural adjustment of trunk
| 2. Stereotyped movements – modulation of basic walking patterns generated in the SC
77
Where does input to the paravermal come from? where does its output go? what is its function?
```
input = SC (limbs)
Output = motor cortex and red nucleus
Fxn = corrects movements if there are errors
```
78
What is the tract that goes through the flocculonodular lobe of the Cb?
Vestibulocerebellum
79
Where does input to the flocculonodular lobe come from? where does its output go to? What is its function?
```
input = vestibular apparatus and vestibular nuclei
output = vestibular nuclei
fxn = Maintenance of equilibrium (balance) [vestibulospinal tract]; Control of eye movements
```
80
When injury occurs to the cerebellum, are the symptoms ipsi- or contralateral to the injury? what is the typical response?
- ipsilateral to injury (Injuries directly to Cb can cause problems but Also due to input or output fibers [pathways, peduncles])
- hypotonia; usually transient and tone returns to normal levels over time
81
If a person has truncal ataxia, where is the injury? limb and gait ataxia? Hand ataxia?
Truncal = vermal or vestibulocerebellar lesions (difficulty sitting or standing) or can be due to paravermal lesion
Limb and gait = paravermal lesion
hand = lateral hemisphere lesion
82
Injury that results in dysequilibrian, truncal ataxia, and abnormal eye movements
Vestibulocerebellum injury
83
Injury that results in dysarthria (speech impairment due to motor problems) and truncal ataxia
spinocerebellar lesion in vermal region
84
injury that results in gait ataxia (wide base gait; pt not able to walk in straight line; different step lengths)
- can be the result of nutritional deficiencies that damage the anterior lobe of the Cb due to poor diets seen in alcoholism
spinocerebellar lesion in paravermal region
85
What are the symptoms of limb ataxia?
1. Dysdiadochokinesia - inability to perform rapidly alternating movements
2. Dysmetria - inability to move the correct distance or location; Will not hit a target
3. Action tremor (intention tremor) - tremor during a movement
4. Difficulties with time intervals - difficulties maintaining a regular rhythm
86
What is seen in injuries to the cerebrocerebellum?
dysarthria and hand ataxia (lateral activating system)
87
Where are the UMN for the lateral corticospinal tract?
- Primary motor cortex
- secondary motor cortex (motor planning areas: premotor, supplementary)
- primary somatosensory cortex
88
Where are the UMN for the corticobulbar tract?
- Primary motor cortex
- secondary motor cortex (motor planning areas: premotor, supplementary)
- primary somatosensory cortex
Same for lat corticospinal for face, lats, and SCM
89
Where are the UMN for rubrospinal tract?
Red nucleus in mid brain
90
Where are the UMN for lat reticulospinal tract?
reticular formation in brainstem
91
Where are the UMN for tectospinal tract?
Superior colliculus in midbrain
92
Where are the UMN for medial reticulospinal tract?
reticular formation in the brainstem
93
Where are the UMN for medial vestibulospinal tract?
vestibular nuclei in brainstem
94
Where are the UMN for lateral vestibulospinal tract?
Vestibular nuclei in brainstem
95
Where are the UMN for medial corticospinal tract?
Cerebral cortex
96
What does lateral corticospinal tract control?
Fine movement, voluntary movement, and fractionation of movement in the distal extremities
97
What does corticobulbar tract control?
voluntary movement in the face, lats, and SCM
98
What does rubrospinal tract control?
facilitates flexion in upper extremities only
99
What does lateral reticulospinal tract control?
Flexion in all extremities
100
What does tectospinal tract control?
Goes to cervical and thoracic cord and orients head and eyes toward stimulus (visual map of the world)
101
Where does the medial reticulospinal tract control?
Extensor muscles to keep you upright
102
What does the medial vestibulospinal tract control?
Keeps the eyes stable (moving your head up and down while reading a paper)
103
What does the lateral vestibulospinal tract control?
input detects how the head is moving and tract controls body extensors to keep us upright for correct balance and posture
i.e., if you are falling, input saying head is rapidly going to the ground, Tract responds by extending body, arms, etc. to keep head from smashing into the ground
104
What does the medial corticospinal tract control?
extension of axial and girdle muscles
