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Mahathi Neurology > 1b Motor Cortical Control > Flashcards

1b Motor Cortical Control Flashcards

1
Q

What is meant by the hierarchical organisation?

A

high order areas of hierarchy are involved in more complex tasks, and lower level areas of hierarchy perform lower level tasks

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2
Q

What do the cerebellum and the basal ganglia do in the motor system of heirarchy?

A

adjust the commands received from the other parts of the motor system

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3
Q

What are the two pyramidal descending tracts?

A

corticospinal
corticobulbar

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4
Q

Why are the pyramidal tracts called pyramidal?

A

because they pass through the pyramids of the medulla

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5
Q

What do the pyramidal descending tracts do?

A

voluntary movement of the body and face muscles

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6
Q

What are the extrapyramidal tracts?

A

descending tracts which do not pass through the pyramids of the medulla

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7
Q

Which descending tracts are responsible for the involuntary movements of balance, posture and locomotion?

A

Extrapyramidal

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8
Q

Where is the primary motor cortex located?

A

Anterior to the central sulcus

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9
Q

What does the primary motor cortex do?

A

Controls fine, discrete and precise voluntary movements

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10
Q

What does the premotor area do?

A

Involved in planning movements, by regulating externally cued movements

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11
Q

what does the supplementary motor area do?

A

Planning complex movements and becomes active prior to voluntary movements

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12
Q

Where does the lateral corticospinal tract decussate?

A

In the medulla - innervates the limb muscles

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13
Q

Where does the anterior corticospinal tract decussate?

A

Spinal cord - innervates the trunk muscles

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14
Q

What is the principal motor tract for voluntary movement of the face and the neck?

A

Corticobulbar

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15
Q

What is the function of the vestibulospinal tract?

A

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

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16
Q

What is the function of the reticulospinal tract?

A

Most primitive descending tract - from medulla and pons
Changes in muscles tone associated with voluntary movement
Postural stability

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17
Q

What is the function of the tectospinal?

A

Orientation of the head and neck during eye movements

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18
Q

What is the function of the rubrospinal tract?

A

Innervate lower motor neurons of flexors of the upper limb

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19
Q

What is paresis?

A

graded weakness of movement

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20
Q

What are the three negative signs of an upper motor neuron lesion?

A

Loss of voluntary movement
Paresis
Paralysis = complete loss of voluntary muscle activity

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21
Q

What is spasticity?

A

Increased muscle tone

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22
Q

What is hyper-reflexia?

A

Exaggerated reflexes

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23
Q

what is clonus?

A

Abnormal oscillatory muscle contraction

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24
Q

What are the positive signs of an upper motor neurone lesion
?

A

Increased abnormal motor function due to loss of inhibitory descending inputs
Spasticity: increased muscle tone
Hyper-reflexia: exaggerated reflexes
Clonus: abnormal oscillatory muscle contraction
Babinski’s sign

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25
Q

what is Apraxia?

A

disorder of skilled movement - patients lose information about how to perform skilled movements

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26
Q

Lesions to which areas can cause apraxia?

A

Frontal lobe and the inferior parietal lobe - premotor cortex, and supplementary motor area

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27
Q

What two diseases are the most common causes of apraxia?

A

Stroke and dementia

28
Q

What is seen in patients with a lower motor neuron lesion?

A

Weakness
Hypotonia
Fibrillations
Fasciculations
Hyporeflexia
Muscle atrophy

29
Q

What is Fasciculations?

A

damaged motor units produce spontaneous action potentials, resulting in a visible twitch

30
Q

What is the difference between fasciculations and fibrillations?

A

Fasciculations = damaged motor units producing twitching,
Fibrillations = individual muscle fibres producing twitching

31
Q

What is motor neurone disease also known as?

A

Amyotrophic Lateral Sclerosis

32
Q

What are the upper motor neuron signs of motor neuron disease?

A

Spasticity (increased tone of limbs and tongue)
Brisk limbs and jaw reflexes
Babinski’s sign
Loss of dexterity
Dysarthria (difficulty speaking)
Dysphagia (difficulty swallowing)

33
Q

What are the lower motor neuron signs of motor neuron disease?

A

Weakness
Muscle wasting
Tongue fasciculations and wasting
Nasal speech
Dysphagia

34
Q

What are the two nucleuses which make up the basal ganglia called?

A

Lentiform nucelus and caudate nucleus

35
Q

What makes up the lentiform nucleus?

A

The putamen and globus pallidus

36
Q

What is the function of the basal ganglia?

A

Making the decision to move
Elaborating associated movements
Moderating and coordinating movements
Performing movements in order

37
Q

What is parkinsons disease/

A

Degeneration of the dopaminergic neurons that originate in the substantia nigra and project to the striatum

38
Q

What are the five associated symptoms of Parkinsons?

A

Bradykinesia
Hypomimic face
Akinesia
Rigidity
Tremor at rest

39
Q

What is bradykinesia?

A

slowness of (small) movements (doing up buttons, handling a knife)

40
Q

What is hypomimic face?

A

face - expressionless, mask-like (absence of movements that normally animate the face)

41
Q

What is Akinesia?

A

difficulty in the initiation of movements because cannot initiate movements internally

42
Q

What is rigidity?

A

muscle tone increase, causing resistance to externally imposed joint movements

43
Q

What is a pill rolling tremor?

A

When the patients hands tremor as if they were polling a pill between two fingers, which with time can spread to other parts of the body

44
Q

What is Huntington’s disease?

A

Degeneration of GABAergic neurons in the striatum, caudate and then putamen

45
Q

What causes Huntingtons disease?

A

CAG repeat on chromosome 4

46
Q

What are some symptoms of Huntington’s disease?

A

Choreic movements
Rapid jerky movements - hands and face affect
Speech impairement
Difficulty swallowing
Unsteady gait
Cognitive decline and dementia

47
Q

What is the most common cause of Ballism?

A

Stroke which affects the subthalamic nucleus

48
Q

What is Ballism?

A

Contralateral, uncontrolled flinging of the extremities

49
Q

What separates the cerebellum from the cerebrum?

A

The tentorium cerebelli

50
Q

What is the function of the vestibulocerebellum?

A

Regulation of gait, posture and equilibrium
Coordination of head movements with eye movements

51
Q

What does damage to the vestibulocerebellum cause?

A

gait ataxia and tendency to fall (even when patient sitting and eyes open)

52
Q

What is the function of the spinocerebellum?

A

Coordination of speech
Adjustment of muscle tone
Coordination of limb movements

53
Q

What can cause degeneration and atrophy of the spinocerebellum?

A

chronic alcoholism

54
Q

What does damage to the spinocerebellum cause?

A

Abnormal gait and stance (wide based)

55
Q

What is the function of the cerebrocerebellum?

A

Coordination of skilled movements, cognitive function, attention and processing of language

56
Q

What does damage to the cerebrocerebellum result in?

A

Affects arms (coordinated movments) and speech

57
Q

What is Ataxia?

A

General impairments in movement coordination and accuracy. Disturbances of posture or gait: wide-based, staggering (“drunken”) gait

58
Q

What is dysmetria?

A

Inappropriate force and distance for target-directed movements (knocking over a cup rather than grabbing it)

59
Q

What is Dysdiadochokinesia?

A

Inability to perform rapidly alternating movements (rapidly pronating and supinating hands and forearms)

60
Q

What is scanning speech?

A

Staccato speech, due to impaired coordination of speech muscles

61
Q

What are the main signs of cerebellar dysfunction?

A

Ataxia
Dysmetria
Intention remor
Scanning Speech
Dysdiadochokinesia

62
Q

What causes a fasciculation?

A

When the muscle fibres of a motor unit lose their nerve supply - they become denervated

Axons of the remaining motor unit grow and reach out to the denervated muscle fibres - reinnervation takes place

Therefore the resulting motor unit is larger and prone to ectopic generation of electrical stimuli in the distal axons which cause muscle contraction = fasciculation

63
Q

What is the striatum?

A

Caudate + putamen

64
Q

What is the lentiform nucleus?

A

Putamen + external globus pallidus

65
Q

What is the result of a stroke affecting the subthalamic nucleus?

A

Ballism

66
Q

Where does the lateral corticospinal tract decussate?

A

In the medulla

67
Q

What is meant by functional segregation?

A

Motor system organised in a number of different areas that control different aspects of movement

Mahathi Neurology (22 decks)

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