Neurological disorder

Question 1

Define excitotoxicity.

Answer 1

Neurons can be become over-excited which leads to damage.

Question 2

Do neurons self-replicate?

Answer 2

No: loss of neurons is a problem.

Question 3

Define an a) intrinsic and b) extrinsic disorder?

Answer 3

a) Caused by genetics

b) Caused by external factors

Question 4

Seizures are always caused by intrinsic factors. True or false?

Answer 4

False: they can be caused by a combination of the two.

Question 5

If new neurons are born, where is this from?

Answer 5

Neural stem cells in the hippocampus or olfactory bulb.

Question 6

Disruption of energy supply to a neuron can cause cell death. True or false?

Answer 6

True.

Question 7

Neural circuits are refined over many years of usage. Why is it so damaging to lost this?

Answer 7

It cannot be exactly replicated.

Question 8

Neurological disorders fall into 2 categories, a) extrinsic or b) intrinsic. Give examples of each?

Answer 8

a) Tumours, traumatic brain injury, infection (e.g. BSE), stroke
b) developmental abnormalities (Down’s), degeneration (Alzheimer’s)

Question 9

Define a seizure.

Answer 9

‘Overly synchronous brain activity’

Question 10

Seizures occur in which life stages?

Answer 10

Childhood or possibly old age: the times when most brain changes occur

Question 11

What percentage of epileptic disorders have genetic causes?

Answer 11

30%

Question 12

What percentage of epileptic disorders have acquired causes, e.g. head traumas etc.?

Answer 12

25%

Question 13

Seizure disorders can be split into 2 categories. What are they?

Answer 13

1. Generalised: no apparent local onset

2. Partial: begin from a focal point

Question 14

What are the 3 types of generalised seizure and what do they do?

Answer 14

1. Tonic-clonic: affects the whole brain. Largely associated with epilepsy.
2. Absence: lapses of awareness often characterised by staring. Often go undetected.
3. Atonic: a sudden loss of muscle tone causing temporary paralysis

Question 15

What is another name for a) tonic-clonic and b) absence seizures?

Answer 15

a) Grand mal

b) Petit mal

Question 16

Partial seizures are often characterised by a series of movements. Why?

Answer 16

Begins from a localised point, but as the seizure spreads along the primary motor cortex you can detect this progression in the person’s movements. Also it spreads to other cortices like the sensory, psychic and autonomic regions which you can see as the person may begin to lose vision, become emotional and begin to sweat or salivate.

Question 17

The progression of partial seizures reflects cortical maps. True or false?

Answer 17

True.

Question 18

Genetic defects that cause seizures often affect what?

Answer 18

Ion channels, thus altering the excitability of neurons.

Question 19

What is photosensitive epilepsy?

Answer 19

Seizures triggered by flashing lights.

Question 20

In which age bracket is photosensitive epilepsy most common?

Answer 20

Children and teenagers.

Question 21

Spatial patterns can also trigger photosensitive epilepsy. True or false?

Answer 21

True.

Question 22

What is the difference between dementia and Alzheimer’s?

Answer 22

Dementia is an impairment of thinking and memory. Alzheimer’s is a further progression of basic dementia whereby language and cognition is also impaired.

People with dementia struggle but can function. People with Alzheimer’s deteriorate until they cannot.

Question 23

What is the difference between dementia and Alzheimer’s?

Answer 23

Dementia is an impairment of thinking and memory. Alzheimer’s is a further progression of basic dementia whereby language and cognition is impaired by degeneration of neurons.

People with dementia struggle but can function. People with Alzheimer’s deteriorate until they cannot.

Question 24

What is vascular dementia?

Answer 24

Dementia brought on by a series of small strokes or changes to the brain’s blood supply.

Question 25

What is fronto-temporal dementia?

Answer 25

Dementia that affects language, semantic memory.

Question 26

What is Pick's disease?

Answer 26

A disorder affecting personaliy, orientation and behaviour. More common in women.

Question 27

What is Creutzfeldt-Jakob disease?

Answer 27

Rapid deterioration of mental function coupled with involuntary movements.

Question 28

What is Huntingdon's disease?

Answer 28

Characterised by involuntary movements. Genetic disease but onset is during later life.

Question 29

What is Parkinson's?

Answer 29

A progressive disorder of the CNS that causes involuntary movement and tremors.

Question 30

Pick's, Creutzfeldt-Jakob, Huntingdon's and Parkinson's sufferers all show signs of dementia. True or false?

Answer 30

True.

Question 31

Alzheimer's disease is a progressive disease that inevitably causes death. True or false?

Answer 31

True: on average there is an 8 year window between diagnosis and death.

Question 32

The Mini Mental State Exam is sometimes used to indicate levels of impairment. Why is it not an accurate diagnostic tool?

Answer 32

Intelligent people may still score well with severe impairment, and stupid people may score badly despite not impairment.

Question 33

Give 4 characteristic physical changes to the brain that occur in Alzheimer's.

Answer 33

1. Enlargement of the ventricles 2. Thinning of the cortex 3. Shrinkage of the hippocampus 4. Plaques and tangles

Question 34

Plaques are formed from amylase. In healthy people what is supposed to happen?

Answer 34

In healthy neurons secretase and gamma-secretase cut amylase precursor to release beneficial components for neuron metabolism.

Question 35

Plaques are formed from amylase. What happens in Alzheimer's sufferers?

Answer 35

Beta-secretase and gamma-secretase cut amylase precursor to give shorter than normal fragments. These are called beta-amyloids, and build up to form toxic plaques tat impair neuronal function.

Question 36

What are tangles made from and how are they formed?

Answer 36

Tau protein: in healthy people tau protein stabilises microtubules. In Alzheimer's tau protein falls apart. Microtubules are destroyed. The build up forms tangles INSIDE the neurons, disrupting internal transport and leading to cell death.

Question 37

In relation to neurons, where are a) plaques and b) tangles found?

Answer 37

a) Outside/between cells | b) Within cells

Question 38

Describe the general progression of Alzheimer's disease.

Answer 38

Episodic memory begins, along with disorientation. Simple tasks become impossible. They become unable to speak, control their bowels, walk or understand what's going on. They become very aggressive or frightened. It's like development in reverse.

Question 39

What are the 4 hypotheses for the cause of Alzheimer's?

Answer 39

1. Cholinergic hypothesis 2. Myelination hypothesis 3. Amyloid cascage hypothesis 4. Metabolism hypothesis

Question 40

Describe the cholinergic hypothesis.

Answer 40

Ach levels are greatly reduced in Alzheimer's sufferers, thus it is thought that reduced Ach leads to reduced signalling which affects learning and memory and may cause plaques and tangles. Drugs that inhibit enzymes that break down Ach have been trialled but there are serious question marks.

Question 41

Describe the myelination hypothesis.

Answer 41

Neurons in humans are myelinated, but this myelin becomes susceptible to damage at around age 50. They are the first neurons to show protein plaques and tangles. This may be why Alzheimer's seems to be a uniquely human disease as we have more myelination that other species.

Question 42

Explain the amyloid cascade hypothesis.

Answer 42

Changes in amyloid metabolism affects the synapses and neuronal functioning (i.e. neurotransmitter release), leading to the build up of plaques and tangles.

Question 43

Explain the metabolism hypothesis.

Answer 43

Metabolic conditions in early life serve as conducive conditions for the formation of plaques and tangles.

Question 44

There is thought to be a genetic component in Alzheimer's. Mutations in which genes cause a) early onset and b) late onset Alzheimer's?

Answer 44

a) Tends to be via familiar inheritance: mutations in the APP (amyloid precursor protein) and PS1/PS2 (presenilin) genes have been noted. b) Inheritance is more complex but APOE (apolipoprotein E) has been implicated

Question 45

Which work by Leinenga and Gotz, 2015 has found potential for new treatments for Alzheimer's?

Answer 45

Plaques and tangles can be physically disrupted with ultrasound.

Question 46

It has been found that immunisation against beta-amyloid can reduce cognitive function significantly. True or false?

Answer 46

True.

Question 47

Describe the cholinergic hypothesis.

Answer 47

Ach levels are greatly reduced in Alzheimer's sufferers, thus it is thought that reduced Ach leads to reduced signalling which affects learning and memory and may cause plaques and tangles. Drugs that inhibit enzymes that break down Ach have been trialled, however it affects motor function in the PNS. Effects cannot be localised.