Motor Pathways Flashcards

1
Q

What is functional segregation of motor control

A

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

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2
Q

What is hierarchical organisation of motor control

A

High order areas of hierarchy are involved in more complex tasks (programme and decide on movements, coordinate muscle activity)
Lower level areas of hierarchy perform lower level tasks (execution of movement)

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3
Q

What modulates and adjusts commands from the motor cortex

A

Basal ganglia and cerebellum

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4
Q

Describe position of the primary motor cortex

A

Precentral gyrus, anterior to the central sulcus

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5
Q

Function of the primary motor cortex

A

Control fine, discrete, precise voluntary movement

Provides descending signals to execute movement

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6
Q

Type of organisation of the primary motor cortex?

A

Somatotopic

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7
Q

What’re the 2 descending motor pathways

A

LATERAL and ANTERIOR CORTICOSPINAL PATHWAYS

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8
Q

Describe the lateral corticospinal pathway starting from the primary motor motor cortex

A

Primary motor cortex motor neurones send their axons down through subcortical structures known as the internal capsule
Internal capsule becomes the cerebral penduncle
fibres pass through the pons and then reemerges at the pyramids in the medulla where 90-95% of fibres decussate.
the fibres then descend along the lateral corticospinal tract.
- At the appropriate level, the fibres synapse with alpha motor neurones in the ventral horn of the spinal cord
axons of those neurones go out through the ventral root to the spinal nerve and out to the muscle intended

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9
Q

Internal capsule becomes the XX

A

cerebral penduncle

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10
Q

Describe the anterior corticospinal pathway starting from the primary motor motor cortex

A

Primary motor cortex motor neurones send their axons down through subcortical structures known as the internal capsule
Internal capsule becomes the cerebral penduncle
fibres pass through the pons and then reemerges at the pyramids in the medulla
5-10% of fibres here DO NOT decussate and descend to form the anterior corticospinal tract
at the appropriate level the fibres then cross over (decussation is actually IN the spinal cord)- these fibres supply the axial musculature

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11
Q

Anterior corticospinal tract supplies the X muscles

A

axial muscles

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12
Q

What are the CORTICOBULBAR PATHWAYS, example?

A

The primary motor cortex’s projections to the motor nuclei within the brainstem e.g. hypoglossal nucleus

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13
Q

PREMOTOR CORTEX location?

A

Frontal lobe anterior to the primary motor on the lateral side of the head

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14
Q

PREMOTOR CORTEX function? Example of its action?

A

Planning of movements
Regulates externally cued movements
intra- and extra-personal space consideration

Resaching for an apple

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15
Q

SUPPLEMENTARY MOTOR AREA/CORTEX location?

A

Anterior to M1, medial to the premotor cortex (dorsal side of head)

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16
Q

SUPPLEMENTARY MOTOR AREA/CORTEX function?Example of its action?

A

Planning complex movements; programming sequencing of movements
Regulates internally driven movements

e.g. the mechanics of speech
SMA becomes active when thinking about a movement before executing that movement

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17
Q

the 2 ASSOCIATION CORTICES?

A
  • POSTERIOR PARIETAL CORTEX

- PREFRONTAL CORTEX

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18
Q

POSTERIOR PARIETAL CORTEX location?

A

Behind the somatosensory cortex

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19
Q

PREFRONTAL CORTEX location?

A

Anterior side of brain

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20
Q

PREFRONTAL CORTEX location?

A

Involved in selection of appropriate movements for a particular course of action

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21
Q

POSTERIOR PARIETAL CORTEX function?

A

Ensures movements are targeted accurately to objects in external space

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22
Q

Which brain area has this function:

Ensures movements are targeted accurately to objects in external space

A

Ensures movements are targeted accurately to objects in external space

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23
Q

Which brain area has this function:

Involved in selection of appropriate movements for a particular course of action

A

Involved in selection of appropriate movements for a particular course of action

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24
Q

Which brain area has this function:
Planning complex movements; programming sequencing of movements
Regulates internally driven movements

A

SUPPLEMENTARY MOTOR AREA/CORTEX

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25
Q

Which brain area has this function:

Regulates externally cued movements

A

PREMOTOR CORTEX:

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26
Q

Which brain area has this function:
Control fine, discrete, precise voluntary movement
Provides descending signals to execute movement

A

Primary motor cortex

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27
Q

Which brain area has this function:

The primary motor cortex’s projections to the motor nuclei within the brainstem

A

Corticobulbar pathway

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28
Q

What/where is the:

LOWER MOTOR NEURON (3 places)

A

The α-motor neuron in the spinal cord, in the ventral horn- and its process out to the musculature (also in the brainstem e.g. the axon from the hypoglossal nucleus)

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29
Q

What is:

UPPER MOTOR NEURON

A

The motor neuron in the primary motor cortex- they have corticospinal or corticobulbur fibres projecting to the next neuron

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30
Q

What is:

PYRAMIDAL tract

A

Lateral corticospinal tract, main motor tract

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31
Q

what does the EXTRAPYRAMIDAL tract innervate

A

Basal ganglia and cerebellum

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32
Q

What is:

Paresis

A

Graded weakness of movements

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33
Q

What is:

Paralysis (plegia

A

Complete loss of muscle activity

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34
Q

What is:

Spasticity

A

Increased muscle tone

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35
Q

What is:

Hyper-reflexia

A

Exaggerated reflexes

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36
Q

What is:

Clonus

A

Abnormal oscillatory muscle contraction

37
Q

What is:

Babinski’s sign

A

Extensor reflex when sole of foot stimulated

38
Q

What causes increased abnormal motor function

A

LOSS OF INHIBITORY DESCENDING INPUTS:

39
Q

What is this known as:

Abnormal oscillatory muscle contraction

A

Clonus

40
Q

What is this known as:

Extensor reflex when sole of foot stimulated

A

Babinski’s sign

41
Q

What is apraxia

A

disorder of skilled movement- patients are not paretic but have lost information about how to perform skilled movements

42
Q

What is apraxia caused by (what lobe and what functional area) (2)

A
  • Lesion of inferior parietal lobe, the frontal lobe (premotor cortex, supplementary motor area)
43
Q

Most common causes of apraxia (2)

A

stroke and dementia

44
Q

Signs and symptoms of lower motor neurone lesions? (6)

A
  • Weakness
  • Hypotonia (reduced muscle tone)
  • Hyporeflexia
  • Muscle atrophy
  • Fasciculations Damaged motor units produce spontaneous APs, resulting in visible twitch
  • Fibrillations Spontaneous twitching of individual muscle fibres; recording during needle electromyography examination
45
Q

What is MOTOR NEURON DISEASE (MND)

A

PROGRESSIVE NEURODEGENERATIVE DISORDER OF THE MOTOR SYSTEM

46
Q

Cause of death in motor neurone disease?

A

respiratory muscles fail, this is usually the cause of death

47
Q

What is Amyotrophic Lateral Sclerosis (ALS)

A

Motor neurone disease

48
Q

UPPER MOTOR NEURON SIGNS of MOTOR NEURON DISEASE (MND)?

A
  • Increased muscle tone (spasticity of limbs and tongue)
  • Brisk limbs and jaw reflexes
  • Babinski’s sign
  • Loss of dexterity
  • Dysarthria
  • Dysphagia
49
Q

LOWER MOTOR NEURON SIGNS of MOTOR NEURON DISEASE (MND)?

A
  • Weakness
  • Muscle wasting
  • Tongue fasciculations and wasting
  • Nasal speech
  • Dysphagia
50
Q

What defines pyramidal neurons

A

not a part of the main descending tract

51
Q

Examples of basal ganglia teas? (4+4 extra)

A
  • Caudate nucleus
  • Lentiform nucleus (putamen & external globus pallidus)
  • Subthalamic nucleus (first three are in the basal forebrain, subcortical structures)
  • Subtantia nigra In the midbrain
  • Ventral pallidum, claustrum, nucleus accumbens, nucleus basalis of Meynert (on the periphery of the basal ganglia
52
Q

What is in the lentiform nucleus

A

putamen & external globus pallidus

53
Q

Is the basal ganglia pyramidal or extrapyramidal

A

Extra

54
Q

LOOK AT THE DOC AND NAME THE PLACES OF THE BASAL GANGLIA

A

DO IT

55
Q

LOOK AT THE DOC AND NAME THE PLACES OF THE MOTOR SYSTEMS

A

DO IT

56
Q

BASAL GANGLIA- FUNCTIONS (3)

A
  • Elaborating associated movements (e.g. swinging arms when walking; changing facial expression to match emotions)
  • Moderating and coordinating movement (suppressing unwanted movements)
  • Performing movements in order
57
Q

What does the striatum consist of (and what does one of the parts it consists of consist of)

A

Striatum is the lentiform (putamen and external Globus pallidus) + the caudate

58
Q

Where does interruption of basal ganglia circuity occur to give you Parkinsons?

A

from substantia nigra to striatum

59
Q

Where does interruption of basal ganglia circuity occur to give you Huntingtons?

A

Between striatum and globus pallidus internal

60
Q

Where does interruption of basal ganglia circuity occur to give you Ballism?

A

Subthalamic nucleus

61
Q

Symptoms of Parkinsons? (5)

A
  • Stooped posture
  • Broad gate
  • Shuffling movement
  • Lewy body pathology seen
  • Cognitive decline in people who live for a long time with it
62
Q

Neuropathology of Parkinsons?

A

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

63
Q

What is different in a brain examined of Parkinsons disease?

A

Locus classicus - dark line (due to neuromelanin)

64
Q

What causes the locus classicus

A

dark line (due to neuromelanin)

65
Q

Where is the locus classicus

A

Midbrain

66
Q

Lost circuitry from the substantia nigra up to the striatum (specifically the caudate nucleus and putamen) will result in …

A

Parkinsons

67
Q

Specifically which areas of the striatum are involved in Parkinson’s

A

Caudate nucleus and putamen

68
Q

Signs and symptoms of Parkinsons?

A
BRADYKINESIA
HYPOMIMIC FACE
AKINESIA
RIGIDITY
TREMOR AT REST
69
Q

What is akinesia

A

Difficulty in the initiation of movements because cannot initiate movements internally

70
Q

What is HYPOMIMIC FACE

A

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

71
Q

What is BRADYKINESIA

A

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

72
Q

3 main pathways to the cerebellum:

A

Inferior cerebellar peduncle
Middle cerebellar peduncle
Superior cerebellar peduncle

73
Q

What is the function of the:
Inferior cerebellar peduncle

And what tract?

A

input from the spinal cord Spino-cerebellar tract

74
Q

What is the function of the:

Middle cerebellar peduncle

A

Transverse pathway that connects the 2 halves of the cerebellum

75
Q

What is the function of the:

Superior cerebellar peduncle

A

Main output pathway of the cerebellum going up to the basal ganglia, thalamus etc

76
Q

What is the layered structure of the cerebellum known as and what are the layers? (3)

A
  • Trilaminar structure(Pial surface outside) Molecular layer, piriform layer, granular layer
77
Q

All output of the cerebellum is from X cells via deep nuclei

A

Purkinje cells

78
Q

What nucleus in the medulla projects to the Purkinje cells and via what fibres

A
  • Inferior olivary nucleus projects to Purkinje cells via climbing fibres
79
Q

2 sources of input to the cerebellum and what fibres are from each and what cells do they protect to?

A
  • Inferior olivary nucleus projects to Purkinje cells via climbing fibres
  • All other input to granule cells via mossy fibres and then onwards via parallel fibres
80
Q

3 divisions of the cerebellum?

A

VESTIBULOCEREBELLUM
SPINOCEREBELLUM
CEREBROCEREBELLUM

81
Q

What division of the cerebellum is in the transverse section

A

VESTIBULOCEREBELLUM

82
Q

What division of the cerebellum is in the sagittal medial section

A

SPINOCEREBELLUM

83
Q

What division of the cerebellum is in the sagittal lateral section

A

CEREBROCEREBELLUM

84
Q

What does this do:

VESTIBULOCEREBELLUM

A

Regulation of gait, posture and equilibrium & coordination of head movements and eye movements

85
Q

What does this do:

SPINOCEREBELLUM

A

Coordination of speech, adjustment of muscle tone and coordination of limb movements

86
Q

What does this do:

CEREBROCEREBELLUM

A

Coordination of skilled movements (playing piano), cognitive function, attention, processing of language and emotional control

87
Q

What is the cause and problems of VESTIBULOCEREBELLAR syndrome

A

Tumour that causes syndrome similar to vestibular disease leading to gait ataxia, and tendency to fall

88
Q

What is the cause and problems of CEREBROCEREBELLAR syndrome

A

Damage that affects mainly arms/skilled coordinated movements (tremor) and speech

89
Q

What is the cause and problems of SPINOCEREBELLAR syndrome

A

Damage (degeneration and atrophy associated with alcoholism) that affects mainly legs and causes abnormal gait and wide stance