10: Brain Damage and Neuroplasticity

Question 1

Parkinson’s disease…

Answer 1

A motor disorder in middle- and old-aged people.

Question 2

Common symptoms (3)…

Answer 2

Tremor when inactive (but not sleep), rigidity in muscles, face becomes mask-like.

Question 3

Lewy bodies…

Answer 3

Lumps of protein found in surviving dopamine neurons of the substantia nigra in autopsy patients.

Question 4

Roughly how many gene mutations have been linked to Parkinson’s?

Answer 4

10

Question 5

All found related gene mutations are responsible for interfering with the function of…

Answer 5

Mitochondria, the cell structures which produce the cell’s energy.

Question 6

Deep brain stimulation…

Answer 6

A treatment method. Electrical stimulation is applied to the subthalamic nucleus, which is connected to the basal ganglia.

Question 7

What are the differences between Parkinson’s and Huntington’s disease? (3)

Answer 7

Huntington’s is rarer, has a genetic basis, and is highly correlated with dementia.

Question 8

Huntingtin…

Answer 8

The single dominant gene responsible for the 50% likelihood that you will develop Huntington’s,

Question 9

When do the first symptoms of Huntington’s appear?

Answer 9

Middle-age, around 40 years.

Question 10

Multiple Sclerosis (MS)…

Answer 10

• Autoimmune disorder.
• Attacks myelin of axons in CNS which causes degeneration of said axons. Hardened (hence name ‘sclerosis’) areas of scar tissue develop in CNS.

Question 11

Experimental autoimmune encephalomyelitis…

Answer 11

Animal model of multiple sclerosis involving injecting them with myelin.

Question 12

Common symptoms of MS (3)…

Answer 12

Ataxia (loss of motor coordination), visual disturbances, and numbness.

Question 13

3 genetic implications for MS…

Answer 13

• Higher concordance in MZ twins (25%: weak)
• 3 x higher in females.
• Higher incidence in caucasians.

Question 14

3 environmental implications for MS…

Answer 14

• Higher incidence in colder climates.
• Positive relationship between susceptibility rates and living in a high-incidence region.
• Higher incidence for smokers.

Question 15

What is the most common cause of dementia?

Answer 15

Alzheimer’s disease.

Question 16

3 early symptoms of Alzheimer’s disease…

Answer 16

• Selective memory loss
• Attention deficits
• Personality changes

Question 17

What are the two defining characteristics of Alzheimer’s disease?

Answer 17

• Neurofibrillary tangles - tangles of protein in neural cytoplasm.
• Amyloid plaques - scar tissue of degenerating neurons and the protein, amyloid.

Question 18

3 areas where neurofibrillary tangles and amyloid plaques are prevalent…

Answer 18

• Entorhinal cortex
• Amygdala
• Hippocampus
  These are all involved in memory.

Question 19

What are the chances of onset if a family member has Alzheimer’s?

Answer 19

50%!

Question 20

Why is it difficult to find a cure for Alzheimer’s?

Answer 20

Because it is uncertain as to what the primary symptom is; amyloid plaques or neurofibrillary tangles.

Question 21

What is the main support for the amyloid hypothesis?

Answer 21

That the associated genetic mutations for early onset have an effect on amyloid synthesis.

Question 22

What important chemical did initial treatments for Alzheimer’s focus on?

Answer 22

Acetylcholine, as decline in the levels of this are one of the first symptoms.

Question 23

Immunotherapeutic approach…

Answer 23

Treatment for Alzheimer’s which involves amyloid vaccines to reduce generation of plaques.
Currently has serious side-effects so too dangerous.

Question 24

Kindling model of epilepsy….

Answer 24

• A type of animal model.
• The gradual building and intensification of seizures triggered by regular electrical stimulations to the brain (particularly the amygdala).
• Convulsions also become somatically generalised.

Question 25

Interictal behaviour…

Answer 25

Behaviour that occurs between seizures in epileptic patients.

Question 26

What is a major disadvantage of transgenic mouse models of Alzheimer’s?

Answer 26

A majority of the models do not demonstrate neurofibrillary tangles, a major symptom.
But triple transgenic mouse models do exhibit these.

Question 27

What is MPTP?

Answer 27

• 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine!

- MPTP is a substance that produces cell loss in substantia nigra.

Question 28

What has the MPTP model of parkinson’s disease discovered?

Answer 28

• Deprenyl. Monoamine agonist that blocks MPTP’s effects.

- Useful discovery for treatment, but not aetiology.

Question 29

What is a widely used method to measure controlled neural degeneration?

Answer 29

Cutting the axons of neurons.

Question 30

Anterograde degeneration…

Answer 30

• Type of neural degeneration.
• Degeneration of the distal segment.
• Distal is the segment between cut and synaptic terminals, the part FURTHEST AWAY from cell body.
• Effects occur soon after.

Question 31

Retrograde degeneration…

Answer 31

• Type of neural degeneration.
• Degeneration of the proximal segment.
• Proximal is the segment between cut and cell body - NEARBY.
• Effects occur a while after.

Question 32

Concerning regeneration, how do olfactory ensheathing cells differ from Schwann cells?

Answer 32

• They aid continual growth of axons projecting from regenerated PNS neurons into the CNS.

Question 33

How does transplantation of foetal tissue work?

Answer 33

• It can develop and integrate into host brain, which would get rid of offending symptoms.
• But has side effects months later.

Question 34

How does transplantation of stem cells work?

Answer 34

When injected, the stem cells can develop into replacing neurons or myelin.

Question 35

What does the term ‘multipotent’ for stem cells mean?

Answer 35

That they can develop into many types of mature cells.