lecture 3

Question 1

what do excitatory neurons/neurontransmitters want to do?

Answer 1

fire

Question 2

what do inhibitory neurons want to do?

Answer 2

modulate firing

Question 3

patterns of activation arise from?

Answer 3

net interactions between both excitatory and inhibitory

Question 4

is activation always stable? if not why?

Answer 4

usually stable - cancel each other out/draw, but can sometimes become unstable

Question 5

if not stable what happens>

Answer 5

result in disinhibition/hyper excitability

Question 6

What is migraine?

Answer 6

when all the canceling out goes wrong

Question 7

how many diff subtypes of migraine? Name them.

Answer 7

3 main:

• Migraine with aura (perceptual aberrations - something u see/smell etc that indicates you that you might have a migraine soon)
• Migraine without aura (just get the pain)
• Aura without migraine (just the anomalous perceptions/occipital migraine)

Question 8

What is aura?

Answer 8

is the term given to many neurological symptoms (including
aberrant perceptions) that can precipitate / occur during the
migraine (or occur on their own).

Question 9

migraine vs headache?

Answer 9

not always the same.

Question 10

what stage of aura/hallucinations are much more common?

Answer 10

simple are much more common than complex.

Question 11

What stage is simple hallucination/aura?

Answer 11

stage 1

Question 12

What stage is complex hallucination/aura?

Answer 12

stage 2

Question 13

example of simple/stage 1/typical aura sensations ?

Answer 13

phosphenes, blobs of light,
scintillations, scotoma, zig-zags, fortification images, geometric
forms, perceptual distortions.

Question 14

What is perceptual distortions?

Answer 14

you see a horizon view of lamppost and one of them is bended.

Question 15

what is symptom of migraine?

Answer 15

• visual discomfort

- visual pain

Question 16

Why do we get migraine?

Answer 16

the result of excessive neural disinhibition

in early visual centres in the brain (V1 / primary visual cortex).

Question 17

what is another term for migraine aura? and why?

Answer 17

the zig zags they meet at right angle so its called fortified hallucination

Question 18

What is Synaesthesia aura?

Answer 18

you hear sounds while seeing sparks of light. a mix-up of Multi-sensory integration/all types of senses mixed together for example smelling colours…

Question 19

What is Metamorphopsia?

Answer 19

visual distortions

Question 20

Who used to use Metamorphopsia?

Answer 20

Microsoft

Question 21

What is Spreading cortical depression?

Answer 21

• neurons become suppressed, but after increased activity

Question 22

how fast does SCD move?

Answer 22

2-5mm/min

Question 23

what is an observation of SCD?

Answer 23

they move according/with sympathy to what you are viewing.

• similarity of the propagation speed of SCD to
  that of the spread of the scotomas in migraine – suggests that
  both may be related to each other in some way (Lashly, 1941)

Question 24

how did they know aura is connected to migraine?

Answer 24

• they manage to map consciousness into brain activity

Question 25

Why is the visual cortex (in particular) in migraine patients particularly susceptible to the initiation of CSD?

Answer 25

- over excitation in excitatory systems in V1 - under-inhibition in inhibitory systems of V1.

Question 26

So is there any evidence that early visual cortex (V1) in migraine patients is under-inhibited?

Answer 26

- VEP (visually evoked potentials). (eeg) - Trans-cranial magnetic stimulation (TMS) of migraine brains. - Brain-imaging (fMRI) - Pattern-glare tasks and visual stress in migraine patients.

Question 27

What is VEP (visually evoked potentials)?

Answer 27

Stronger responses in migraine aura patients. - stronger visual neurons

Question 28

What some evidence suggest about a subsection of migraine population?

Answer 28

Some evidence suggests that a subsection of the migraine population may have less inhibited visual cortices (V1).

Question 29

What is perceptual masking?

Answer 29

- gone before your brain can see because its gone very fast.

Question 30

What does TMS produce?

Answer 30

brief, strong, magnetic | pulse applied to the skull / brain.

Question 31

What can TMS be used for?

Answer 31

to produce ‘virtual lesions’ in the brain and help explore function.

Question 32

if brain is less inhibited in migraine with aura??

Answer 32

- lower phosphene threshold, lower intensity, brain is less inhibited.

Question 33

Aurora et al. (1998) Conclusion:

Answer 33

far easier to induce phosphenes via TMS in migraine patients than in control patients

Question 34

spike in the graph? slide 24

Answer 34

checks presented on the board

Question 35

Where do big fMRI responses occur?

Answer 35

in migraine with aura patients

Question 36

what is visual discomfort?

Answer 36

info from the world can be visually uncomfortable to view and induce visual stress/irritability in the observer.

Question 37

visual discomfort affects what are? and what does the discomfort cause?

Answer 37

high irritable to the visual cortex/eyes visual stress

Question 38

What is visual stress?

Answer 38

Visual Stress is a sensitivity to visual patterns, particularly stripes. In some individuals this condition can cause visual perceptual problems, which interfere with reading.

Question 39

what is visual stress and discomfort associated to?

Answer 39

associated with certain neurological conditions such as: - migraine with aura - headache - photsensitive epilepsy - meares-irlen syndrome

Question 40

What is Meares - irlen Syndrome?

Answer 40

a form of visual stress which leads to difficulties with fine vision tasks such as reading.