Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

NEUROLOGY AND NEUROSCIENCE 2 > MOTOR CORTICAL CONTROL > Flashcards

MOTOR CORTICAL CONTROL Flashcards

(59 cards)

Start Studying
1
Q

What us the hierarchical organisation of motor control

A

High order areas of hierarchy are involved in more complex tasks (programme and decide on movements, coordination)

Lower level areas of hierarchy perform lower level tasks (execution of movement)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How is the motor system organised?

A

By functional segregation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Name the descending pyramidal tracts

A

Corticospinal
Corticobulbar

Voluntary movements of body and face

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Name the extra pyramidal tracts

A

Vestibulospinal
Tectospinal
Reticulospinal
Rubrospinal

Involuntary movements for balance, posture and locomotion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the decussation of the corticospinal tract

A

85-90% decussate to the lateral corticospinal tract

10-15% remain on same side via anterior corticospinal tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does the lateral corticospinal and anterior corticospinal tract innervate?

A

Lateral - limb muscles

Anterior - trunk muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does the corticobulbar tract do?

A

Principal motor pathway for voluntary movements of the face and neck

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does the vestibulospinal tract do?

A

Stabilises head during body movements or as head moves
Coordinate head movements with eye movements
Mediate postural adjustments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does the reticulospinal tract do?

A

Changes in muscle tone associated with voluntary movement
Postural stability

Descends from medulla and pons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What does the tectospinal tract do? And where does it descend from?

A

Orientation of head and neck during eye movements

Descends from superior colliculus of midbrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the rubrospinal tract do?

A

In humans mainly taken over by corticospinal tract
Innervates lower motor neurons in flexors of upper limb

Descends from red nucleus of midbrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does an upper motor neuron lesion cause?

A

Negative signs:

  • Loss of voluntary motor function
  • Paresis (graded weakness of movements)
  • Paralysis
Positive signs:
- Increased abnormal motor function due to loss of 
  inhibitory descending inputs
- Spasticity (increased muscle tone)
- Hyper-reflexia
- Clonus
- Babinski's sign
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is apraxia and what could cause it?

A

Disorder of skilled movement. Not paretic but patients have lost info on how to perform skilled movements

Lesions/diseases of:

  • inferior parietal lobe
  • frontal lobe (premotor cortex/supplementary motor area)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the most common diseases causing apraxia?

A

Stroke and dementia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does a lower motor neuron lesion cause?

A 
Weakness
Hypotonia
Hyporeflexia
Muscle atrophy
Fasciculations
Fibrillations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are fasciculations?

A

Damaged motor units which produce spontaneous APs resulting in a visible twitches

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are fibrillations?

A

Spontaneous twitching of individual muscle fibres recorded during needle electromyography examination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is motor neuron disease (MND)?

A

Spectrum of progressive neurodegenerative disorder affecting upper and lower motor neurones

AKA amyotrophic lateral sclerosis (ALS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the upper motor neuron symptoms of MND?

A 
Spasticity
Brisk limbs and jaw reflexes
Babinski's sign
Loss of dexterity
Dysarthria
Dysphagia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the lower motor neuron symptoms of MND

A 
Weakness
Muscle wasting
Tonge fasciculations and wasting
Nasal speech
Dysphagia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

List the nuclei in the basal ganglia

A

Caudate nucleus
Putamen (caudate and putamen together called striatum)
Lentiform nucleus
Nucleus accumbens
Subthalamic nuclei
Substantia nigra
Ventral pallidum, claustrum, nucleus basalis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the function of the caudate nucleus?

A

Decision to move

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Which nuclei are responsible for elaborating associated movements e.g. swinging arms when walking, changing facial expression to match emotion

A

Lentiform nucleus (putamen + external globus pallidus)

Nucleus accumbens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the function of the substantia nigra?

Study These Flashcards
A

Moderating and coordinating movement (suppressing unwanted movement)

25
Which parts of the basal ganglia circuitry are affected in Parkinson's disease, Huntington's disease and Ballism?
Parkinson's disease - between striatum and substantia nigra (rostral) Huntington's disease - striatum leading to globus pallidus Ballism - subthalamic nucleus
26
What is Parkinson's disease?
Degeneration of the dopaminergic neurons that originate in the substantia nigra and project to the striatum
27
List the symptoms of Parkinson's disease
Bradykinesia - slowness of small movements Hypomimic face - expressionless, mask-less Akinesia - difficulty in the initiation of movements because cannot initiate movements internally Rigidity - muscle tone increase causing resistance to joints Tremor at rest - 4-7 Hz starting in one hand with time spreading to other parts of body "pill rolling tremor"
28
What is pathology of Huntington's disease?
Genetic degeneration of the GABAergic neurons in the striatum, caudate and then putamen
29
Describe the genetic mutation which causes Huntington's disease
Chromosome 4 Autosomal dominant CAG repeat
30
What are the symptoms of Huntington's disease?
Choreic movements - jerky movements of hands and face affected first then legs and rest of body Speech impairment Dysphagia Unsteady gait Cognitive decline and dementia in later stages
31
What is ballism?
Sudden uncontrolled flinging of the extremities | Usually caused by stroke affecting subthalamic nucleus with symptoms occuring on contralateral side
32
What is the function of the cerebellum?
Coordinator and predictor of movement Takes signals on their way down and compares it with sensory signals from receptors on their way up to coordinate movements and make them fluid
33
Name the 3 parts of the cerebellum and point them out on a diagram
Vestibulocerebellum Spinocerebellum Cerebrocerebellum
34
What is the function of the vestibulocerebellum?
Regulation of gait, posture and equilibrium | Coordination of head movements with eye movements
35
What is the function of the spinocerebellum?
Coordination of speech Adjustment of muscle tone Coordination of limb movements
36
What is the function of the cerebrocerebellum?
Coordination of skilled movements Cognitive function, attention, processing of language Emotion control
37
What does damage e.g. tumour in vestibulocerebellum cause?
Syndrome similar to vesitbular disease: | - gait, ataxia and tendency to fall
38
What does damage (e.g. chronic alcoholism causing degeneration and atrophy) in spinocerebellum cause?
Affects mainly legs causing abnormal gait and wide-based stance
39
What does damage to cerebrocerebellum cause?
Damage affects mainly arms/skilled coordinated movements (tremor) and speech
40
List the main signs of cerebellar dysfunction
``` Ataxia Dysmetria Intention tremor Dysdiadockokinesia Scanning speech ```
41
What is the difference between extrafusal and intrafusal muscles
Extrafusal - muscle fibres have contractile elements in them Intrafusal - muscle fibres which contain the sensory organs which respond to stretch and tension. Responsible for conveying the sensory info about the status of a muscle
42
What is an alpha motor neuron?
The lower motor neurons of the brainstem and spinal cord which innervate the extrafusal muscle fibres of the skeletal muscles.
43
Which part of the spinal cord do alpha motor neurons occupy?
Ventral horn
44
What is a motor neuron pool?
All the alpha motor neurons that innervate a single muscle
45
What are the two mechanisms in which the brain regulates the amount of force that a muscle produces?
Recruitment - Smaller units recruited and derecruited first allowing fine control Rate coding - The more a motor unit fires the greater the force produced. Slow units fire at a lower frequency.
46
What causes muscle fibre type IIB - IIA change?
Training e.g. gym
47
What causes type I to II?
Severe deconditioning: - Spinal cord injury - Astronauts due to microgravity
48
What happens to motor units in ageing?
Loss of type I and II | Preferential loss of type II thus greater proportion of I
49
What are descending (supraspinal) control of reflexes
Higher centres of CNS exert inhibitory control on stretch reflex Reflexes can be influenced by specific motions which remove the descending inhibition from the brain causing the reflex to become larger
50
What is the Jendrassik manoeuvre?
Clenching teeth, making a fist, pulling against locked fingers causes the patellar tendon reflex to be larger
51
What is decerebration?
Surgery to separate cortex from lower brain stem and spinal cord regions Shows that excitatory control (inhibition) comes from higher centres of CNS. Without the higher centres only lower centres left causing rigidity and spasticity giving over-active and tonic stretch reflex
52
List the 5 types neurons which control reflexes
``` Activating alpha motor neurons Activating inhibitory interneurons Activating propriospinal neurons Activating gamma motor neurons Activating terminals of afferent fibres ```
53
What are activating propriospinal neurons
Interneurons which go up and down to activate nearby muscles to help with movement
54
What are gamma motor neurons
Alter the sensory organs that are housed in intrafusal muscles. Allows the muscle to remain sensitive to stretch when muscle at different lengths
55
What is clonus?
Form of hyper-reflexia - involuntary and rhythmic muscle contractions
56
What is Babinski's sign?
When sole of foot stimulated with blunt instrument the big toe curls upwards when it normally curls downwards Associated with upper corticospinal tract neuron lesion
57
Why does Babinski's sign not work in infants?
Their big toe will curl upwards due to an undeveloped corticospinal tract
58
Why does hyper-reflexia occur?
Loss of descending inhibition | Upper motor neuron lesion
59
Why does hypo-reflexia occur?
Lower motor neuron diseases as efferent limb of reflex not functioning

NEUROLOGY AND NEUROSCIENCE 2 (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions