L1.3 Supraspinal

Question 1

What is the function of the brainstem?

Answer 1

• Sends out different intensity signals (changes from walk → gallop)
  
  • Change of gait

Question 2

What is the function of the Basal Ganglia?

Answer 2

• 1) Selection of complex motor movement
• 2) Evaluates success of actions (skills → become better)
• 3) Initiate movement

*Many signals are inhibitory*

Question 3

What are the Basal Ganglia disorders?

Answer 3

• (Hyperkinesia - ↑abnormal muscle activities)
• Parkinsons: Pedestal turning, No postural readjustment (difficulty initiation of movement), high tremor
  
  • Lacks substantia nigra (part of basal ganglia – black substance in midbrain)
• Chorea: Interrupted gait, arms out to maintain balance
• Huntington disease: unwanted movements occurring → alters gait
  
  • brain undergoes neuro degeneration

Question 4

What is the function of the Cerebellum?

Answer 4

*has the same pattern of neurons connected*

• 1) Coordinate timing & sequence of muscle actions & movements
• 2) Maintain muscle tone
• 3) Motor learning
• 4) Planning sequences for complex movements

Question 5

What is the Cerebellum disorder?

Answer 5

• (Ataxia) – Unable to follow a task, problem with coordination
  
  • Gait = wide stance → keep CoG
    
    • Cannot put one foot in front of the other

Question 6

What is the function of the Cortical (cerebral region)?

Answer 6

*lots of input from parietal parts*

• 1) Voluntary initiation of gait
• 2) Selection of gait as part of goal directed motor behaviour
• 3) Integration of complex goal → adjustment to environmental conditions (walking over obstacles)

Question 7

What are the cerebral disorders?

Answer 7

• Weakness in one leg – extensor stronger than flexors → could hyperextend, but can’t bend leg → becomes stiff.
  
  • Circumducting gait
• Strokes: Damaged side of leg completely stiff, wrist/elbows/fingers flexed and stiff
  
  • Hemiparietic gait

Question 8

What happens when brain control over the spinal cord is compromised?

Answer 8

• Spinal locomotor circuits cannot be initiated
• Motor neurons lose inputs (many inhibitory) → motor neurons exhibit hyperexcitatbility → ↑muscle tone above normal levels
• Spinal lesions → after a while → spinal reflex circuits oversensitiesd & also ↑muscle tone above normal levels