Movement Control

Question 1

What 5 elements aid in postural stability
How do they do this
What can happen to these elements when you don’t use them?

Answer 1

POSTURAL CONTROL VIA REFLEXES

• ay coactivation
  
  • changes sensitivity of spindles by changing proportional contractions

Postural sway
-dynamic spindle control

Vestibular
-input from vestibular apparatus => vestibular nuclei => SC => reflex ext, flexor innervation

Visual
-eye => LGN => sup coll =(TST)=> SC

Pressure
-skin pressure receptors, especially in feet

These reflexes can be reset

Question 2

What is tabes dorsalis

What are the consequences of this

Answer 2

Loss of pressure receptors in the feet

-close eyes => fall

Question 3

What 3 elements must you have before you even start thinking about moving
-where do you get feedback from

Answer 3

TONE => POSTURE => BALANCE

• visual
• vestibular
• proprioception

Question 4

What is the 1st step in movement
What part of the brain is needed
What is the blood supply

What happens if this region is damaged
-how can it be damaged

Answer 4

Prefrontal cortex
-idea and motivation
ACA

Vulnerable to head injury => lose motivation to move

Question 5

What is the 2nd step in movement
What 2 brain parts coordinate this
What is the blood supply

What happens if these regions are damaged

Answer 5

Premotor cortex

• planning
• apraxia, dyspraxia

Supplementary motor cortex

• programming
• akinesia, bradykinesia, hypokinesia

MCA, ACA

Question 6

What brain region supplies sensory info to the premotor and supplementary motor areas
What is the blood supply

What happens if this region is damaged

Answer 6

Post parietal

• analysis of sensory info from visuals
• apraxia, dyspraxia

MCA

Question 7

What brain region is involved in both the retrieval of motor memory and error corrects during movement
What is the blood supply

What happens if this region is damaged

Answer 7

Cerebellum

• motor memory, balance
• coordinates motor commands and proprioceptive feedback and corrects errors

Dysmetria (faulty error correction)
Ataxia (errors in mv)
Asynergia (faulty coordination)
Intentional tremor (Parkinsons)

MS (affects myelinated neurones

SC
AIC
PIC

Question 8

What brain region is involved in the programming of movement
-what specifically does it affect
-how does it do this
What is the blood supply

What happens if this region is damaged

Answer 8

Basal ganglia

• amplitude and frequency of contractions programmed via many nuclei
• direct and indirect pathway

Parkinsons

• chorea, athetosis
• resting tremor
• akinesia/bradykinesia/hypokinesia

MCA, ACA, AchA

Question 9

What brain region carries out the movement after planning and programming

• how does it do this
• describe the route of the fibres and the respective blood supplies

Answer 9

Primary motor cortex (CST)
-MCA, ACA

Internal capsule

• post limb (peripheral) MCA + AchA
• genu (face) MCA

SC
-AH => peripheral nerve => NMJ

Question 10

Where do we receive sensory feedback from to stop the movement
-how?

Answer 10

Visual
Vestibular
Peripheral
-spindles, GTO
-joint
-cutaneous pressure

Question 11

What can happen when the motor cortex, CST is damaged

Answer 11

Flaccid paralysis (damage in cortex?)

• acute => contralateral paralysis
• chronic => motor cortex reorganization and extrapyramidal dominance

Spastic paralysis (damage in UMN)

• withdrawal reflex dominant
  
  • increased a motor activity => increased stretch reflex