Motor 1 Flashcards

1
Q

Motor control is a functional hierarchy, what are its levels, their anatomical components and function?

A

High:

  • Basal Ganglia and association neocortex
  • Goal & movement strategy to achieve the goal

Middle:

  • Motor Cortex & Cerebellum
  • Sequence of muscle contractions to smoothly achieve the goal

Low:

  • Brain stem & Spinal cord
  • Activation of motor neurons and interneurons
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2
Q

How do we divide the motor tracts?

A
Into:
Ventromedial white matter tracts:
- Tectospinal
- Anterior CST
- Vestibulospinal
- Pontine & Medullary Reticulospinal Tracts

Lateral white matter tracts:

  • Rubrospinal
  • Lateral CST
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3
Q

What tracts are contained in the ventromedial white matter and what do they control?

A
  • Vestibulospinal
  • Tectospinal
  • Recticulospinal

They control posture and locomotion, originating in the brainstem

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4
Q

What tracts are within the lateral white matter and what do they control?

A

Corticospinal & Rubrospinal

They control voluntary movements, with inputs from the cortex

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5
Q

Whats the function of the vestibulospinal tract?

A

It takes signals from the vestibular system through the CrNVIII nuclei to the spinal cord to stabilize the head & neck

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6
Q

Whats the function of the tectospinal tract?

A

Maintains eye stability as the body moves

Originating in the Superior Coliculus

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7
Q

Whats the function/origin of the recticulospinal tracts?

A

Split into pontine & medullary origins

They handle reflexive control of posture & balance using trunk & anti-gravity limb muscles

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8
Q

Whats the function of the Corticospinal (CST) tract?

A

Conscious skeletal muscle control originating in the Primary Motor Cortex

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9
Q

Whats the origin of the rubrospinal tract? (RST)

A

Starts in red nucleus of the midbrain

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10
Q

For comparison what tracts does pain and general sensory info travel the spine in?

A

Spinothalamic

  • Ventrolateral White matter
  • Carries 2nd order pain fibres from contralateral body

Dorsal Column
- Carries ipsilateral general sensory info in the dorsal white matter by the dorsal horn

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11
Q

IF you have a lesion of the CST & RST you lose fine motor movements of the upper limbs, what happens if it only affects the cST?

A

You lose the movements as before but after a few months the RST takes over and you regain fine motor control

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12
Q

Explain the distribution of LMN cell bodies in the spinal grey matter?

A

They show somatotopic distribution.

The more medial a limb muscle (or an axial muscle) the more medial its cell body in the grey matter

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13
Q

What areas of the cortex are involved in motor control?

A

The primary motor cortex (Pre-central gyrus or Area 4)

Also Area 6 is rostral (anterioventral, closer to nose) to area 4 and contains:

  • Premotor Area
  • Supplementary Motor Area
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14
Q

What would happen if you damaged Posterior Parietal Cortex (Area 5/7)?

A

Since its responsible for the sensory somatotopic image of the contralateral body you could lose perception of one side of the body (Hemispatial Neglect)

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15
Q

How does the passage of motor control descisions occur in the cerebrum?

A

Prefrontal cortex & Posterior parietal cortex decide on the movement
-> Axons converge on area 6
Where the movement is planned by the pre-motor & supplementary motor areas
-> Then axons travel to Area 4 (Primary motor cortex) where the neurons of the CST/RST are activated

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16
Q

Area 6 neurons fire roughly 1second before we make a movement, when else do they fire?

A

When we think about a movement or watch someone else do it.

Therefore the same motor circuits as plan our movements also allow us to comprehend other peoples movements