Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Brain and Behaviour > The Neural Control of Movement > Flashcards

The Neural Control of Movement Flashcards

You may prefer our related Brainscape-certified flashcards:
The Brain flashcards
1
Q

what is the hierarchical organisation of movement

A
  1. Lower motoneurons (LMN)
  2. Upper motoneurons (UMN)
  3. Cerebellum
  4. Basal ganglia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what are LMNs

A
  • these are alpha motoneurons that constitute the final common pathway of all motor commands
  • they are part of a motor unit
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what do the LMNs innervate

A

Directly innervate skeletal muscles to produce muscle contractions

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

where are the cell bodies of the LMNs

A

Cell bodies in the ventral horn of the spinal cord and exit via ventral roots

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

what are the 4 anatomical points where the LMN injury can occur

A
  1. Ventral horn
  2. Ventral root
  3. The NMJ
  4. Skeletal muscle itself
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what does Lower motor neurone injury arise from

A
  • arises from damage to alpha motoneurons
  • for example diseases that selectively affect alpha motor neurones such as polio or localised lesions near the spinal cord
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what are the characteristics set of symptoms symptoms of LMN injury

A
  1. Muscle atrophy
  2. Hypotonia (reduced muscle tone) – because alpha motor neurons are the only way to stimulate extrafusal muscle fibres, the loss of these neurons causes a decrease in muscle tone
  3. Hyporeflexia (reduced or absent myotactic /stretch reflexes) this is because the alpha motor neuornes that cause muscle contraction are damaged
  4. Flaccid paralysis / muscle weakness
  5. Fasciculations- damaged alpha motor neurons produce spontaneous action potentials  visible twitches of affected muscle(s).
  6. Fibrillations
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are Upper motor neurones

A

All motor system neurons higher in the hierarchy are referred to as UMNs

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

what do UMN do

A

these carry voluntary motor commands to LMNs

  • they directly or indirectly synapse onto the LMNs
  • there are 3 functionally distinct motor tracts
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

where are the cell bodies of the UMNs

A

Cell bodies in the cerebral cortex and brainstem

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

what are the upper motor neurone tracts

A

Corticospinal (lateral & anterior/ventral)

Reticulospinal & Vestibulospinal

Rubrospinal

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

what does the corticospinal tract do

A

precise motor movements

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what do the reticulospinal and vestibulospinal tract do

A

Gross movements

Facilitates flexor movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what does the rubrospinal tract do

A

posture and balance

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

what are the 3 main synaptic inputs into the LMNs

A
  1. UMN of descending tracts (corticospinal, reticulospinal, vestibulospinal, rubrospinal)
  2. interneurons locally
  3. Local sensory nerve fibres (part of reflex arcs)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

where does the corticobulbopsinal tract run

A

From the motor cortex

To the brainstem

Courses through the internal capsule (a bundle of axons from the motor cortex)

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

what are the 2 components of the corticokbulbospinal tract

A
  • corticobulbal fibres

- corticospinal tract

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

where do the corticobulbal fibres decussate

A
  • they decussate at the midbrain
  • synapse onto LMNs destined for the face
  • will synapse onto motor fibres of the CNV
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

where do the corticospinal tract decussate

A

motor fibres destined for the arms & legs continue down and decussate at the lower medulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what do the corticospinal tract form

A
  • lateral corticospinal tract and small anterior corticospinal tract
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what does the lateral corticospinal tract innervate

A

innervate LMNs going to muscles of the limbs (hands & thumbs)

22
Q

what does the anterior corticospinal tract innervate

A

 innervate LMNs going to shoulder and neck muscles (axial muscles)

23
Q

what makes up the extrapyramidal system and where does it originate from

A
  • they originate from the brainstem as the uMN cell body is in the brainstem

Reticulospinal – originates from the reticular formation of pons

Vestibulospinal – originates from the vestibular nuclei in the upper medulla/lower pons

Rubrospinal – originates from the red nucleus in the midbrain

24
Q

what is tension in the muscles due to

A

Tension in muscles due to small amounts of contraction (this produces slight resistance to passive movement)

25
Q

how is Tone maintained

A

Tone is maintained reflexively by stretch & gamma motoneurons, and is adjusted to the needs of posture and movement
- it is also regulated by descending motor pathways

26
Q

how do you maintain posture

A
  • To maintain posture, muscle tone is constantly finely adjusted (happens unconsciously)
  • Input from higher levels of the nervous system
27
Q

define spasticity

A

Increased muscle tone due to loss of inhibition of gamma () motoneurons

28
Q

define rigidity

A

Increased muscle tone due to loss of inhibition of α motoneurons

29
Q

why does spasticity occur

A
  • The strength of the stretch reflex is controlled by the gamma motoneurons.
  • Normally, gamma motoneurons receive both excitatory & inhibitory input in balance.
    However when there is increased excitation or decreased inhibition of gamma motoneurons this increases the tension of intrafusal muscle fibres which cause the 1a muscle spindle afferent to become more sensitive to muscle stretch. This results in spasticity.
30
Q

what can upper motor neurone be due to

A

due to stroke, tumors, blunt trauma

31
Q

what are the characteristic symptoms of upper motor neurone injury

A 
Spasticity
Hyperreflexia 
Cog wheel rigidity 
Clonus/ clonic reflexes 
Babinski sign
32
Q

what are the regions of the cortex involved in the motor control

A 
A – Prefrontal cortex
B – Frontal eye fields 
C – Premotor cortex & Supplementary cortex 
D – Primary motor cortex
(Broca’s)
33
Q

what makes up the motor cortex

A
  1. posterior parietal cortex
    2, association motor cortex
  2. primary motor cortex
34
Q

what does the posterior parietal cortex do

A

Areas 5&7

Decide to move (READY)

35
Q

what does the association motor cortex do

A

Premotor & supplementary cortex
Area 6 (& 8)
Planning to perform complex tasks or movements (SET)

36
Q

what does the primary motor cortex do

A

Area 4

Activation of descending motor pathways to bring about movement (GO!)

37
Q

what does damage to the association cortex result in

A

apraxia

38
Q

What is apraxia

A

Apraxia is the impairment in motor planning and strategies, and the inability to perform complex learned motor tasks

39
Q

How do you test for Apraxia

A

get patient to arrange a set of blocks to match an example block-structure in front of them. They can move the blocks individually, but cannot come up with a motor plan to arrange them properly.

40
Q

what is a neuromuscular disorder

A

A condition affecting one or more of the following:

  • Muscles
  • Nerves
  • NMJ
  • Motor or sensory nerve cell body
41
Q

what is myasthenia gravis

A
  • this is a chronic and autoimmune condition and a disorder of the NMJ
42
Q

what are the symptoms of NMJ

A

Weakness in skeletal muscles

Fatiguability

Worsens after periods of activity and improves after periods of rest.

Muscles that control eye and eyelid movement, facial expression, chewing, talkingand swallowing are most commonly affected, although muscles that control breathing, neck and limb movements may also be affected.

43
Q

what causes myasthenia gravis

A

In myasthenia gravis, antibodies (immune proteins) block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction, which prevents the muscle from contracting.

44
Q

what is Gower’s Sign

A

indicates weakness of proximal muscles in the lower limbs.
Patient has to use their arms and hands to ‘walk’ up their own body from a squatting position due to lack of hip and thigh muscle strength.

45
Q

what are primary motor muscle disorders

A
  • Gower’s Sign
  • inflammatory myopathies (polymyositis)
  • congenital myopathies,
  • Duchenne muscular dystrophy
46
Q

what are the 3 lobes of the cerebellum

A

anterior, posterior and flocculonodular

47
Q

what are the 3 clinically important function zones of the cerebellum

A

Vestibulocerebellum

Spinocerebellum

Cerebrocerebellum

48
Q

what does the vestibulocerebellum do

A 
Balance & posture
Eye movements (VOR)
49
Q

what does the spinocerebellum do

A

Locomotion

Voluntary movements of arms & legs

50
Q

what does the cerebrocerebellum do

A

skilled motor tasks e.g. speech, hand-eye co-ordination, and cognitive eye movements

51
Q

what is the role of the basal ganglia

A

Initiation and sequencing/maintenance of
voluntary movements

Enables motor program switch

Regulates intensity of slow and stereotyped movements

Inhibits unnecessary movements

  • basically it controls the selection, start and stop posts of motor programs
52
Q

what is the basal ganglia made out of

A
  1. Caudate (head and tail)
  2. Putamen
  3. Globus pallidus (internal and external)
  4. Substantia nigra (pars compacta and pars reticulata)
  5. Subthalamic nucleus

Brain and Behaviour (34 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions