Motor control (Lect 10)

Question 1

Parkinsons disease

Answer 1

degeneration of dopamine neurons in basal ganglia, in substantia nigra

Question 2

PD symptoms

Answer 2

+ symptoms: that shouldn’t be there
Tumor, rigidity, involuntary movements

• negative symptoms: that should be there but are not
  akinesia, posture, action initiation, locomotion, speech

Question 3

Drug treatments for PD

Answer 3

L-Dopa (3 or 4 times a day for the rest of the life)
Dopamine agonist
Deep brain stimulation ( sub thalamic nucleus, can be turned on whenever)

Question 4

Study on patients over time with L-Dopa use

Answer 4

Marsden et al (1977)
- 15% never get any positive effect
- 85% respond positively but
1/3 actually continue to do so
1/3 have slowly declining effects
1/3 will be back to or worse than before they started treatment.

Question 5

Study on Dopamine agonist

Answer 5

Rascol et al (2000)

• reduce amount of L-Dopa intake and supplement it with dopamine agonist
• should prolong effectiveness of L-Dopa

Question 6

Tourettes Syndrome

Answer 6

DSM-5: 2 or more motor ticks and 1 or more vocal ticks. vocal ticks can be inarticulate or articulate

• also dopaminergic problems, but too high levels of dopamine
• DA blockers provide symptomatic relief
• worse under stress and should not be tried to suppress or else it would be worse

Question 7

Basal Ganglia motor roles

Answer 7

BG: is the gatekeeper for actions (Mink, 1996)
- PD: inability to remove inhibition of motor plans that are not required
inability to fully suppress unwanted motor plans (tremors)
-TS: inability to suppress unwanted motor plans (ticks)

Question 8

Cerebellar Ataxia

Answer 8

damage to cerebellum: ataxia
- initiation and termination problems
- jerky and inaccurate movements
- damage to medial: stance and gait, initiation
Intermediate: limb movement control
Lateral: adjusting movements, timing

Question 9

Apraxia and the two main types

Answer 9

Problems with skilled motor movements

• typically damage to left parietal lobe
• Ideomotor: problems with willful movement
• Ideational: Failure of sequencing tasks (like making a cup of tea)

Question 10

Phantom limbs

Answer 10

• experience of sensation in amputated limb
• can occur for any body part or internal tissue
• experience is usually pain, can be movement too

Question 11

Phantom Limb explanation

Answer 11

Stimulation of face area creates feelings of phantom hand

• bizarre feeling of being touched (when eyes closed)
• cortical remapping of brain tissue: face info activates are that has been taken over what used to be arm area
• penfields map: hand area is right next to face area

Question 12

relieving phantom pain

Answer 12

• mirror box technique by Ramachandran
• importance of visual feedback
• makes it look like phantom limb is actually there

Question 13

Patient IW

Answer 13

• shows the importance of feedback
• lost all sense of touch or feeling, no proprioception below neck
• result: rest of life in bed or wheel chair
• only possible feedback is via vision
• patient has learned to use vision as feedback to help produce movement.