Observing the Brain

Question 1

5 methods to observe the brain

Answer 1

• Lesion deficit model
• CT scans (computerised tomography)
• PET scans (positron emission tomography)
• fMRI (functional magnetic resonance imaging)
• EEG (electroencephalography)

Question 2

what is the lesion deficit model

Answer 2

• Oldest method
• Brain damage linked to brain behaviour change
• Phineas Gage (1848) railroad incident

Question 3

strengths of the lesion deficit model

Answer 3

o Direct
o Real and natural data
o Pre and posy behaviour measurement (HM)

Question 4

weaknesses of the lesion deficit model

Answer 4

o Variability (between patients and injuries)
o Temporal challenges (brain improvement differs)
o Ethics

Question 5

what are CT scans

Answer 5

series of x-rays

Question 6

strengths of CT scans

Answer 6

o Quick (good for acute trauma)
o High resolution - Great visualisation of bone and blood
o 3D reconstruction (combine images)

Question 7

weaknesses of CT

Answer 7

o Uses ionising radiation which is harmful
o Not great for soft tissue (the brain!)
o Snapshot

Question 8

What are PET scans

Answer 8

• Monitoring radioactive (radiolabelled) tracer
• E.g. glucose in AD, Pittsburgh compound B (binds fibrillar beta-amyloid)

Question 9

PET scans and AD

Answer 9

• Monitoring radioactive (radiolabelled) tracer - glucose in AD, Pittsburgh compound B (binds fibrillar beta-amyloid)

Question 10

strengths of PET

Answer 10

o Very specific depending on tracer
o Measures absolute (exact) levels of activity
o Combine with CT

Question 11

weaknesses of PET

Answer 11

o Uses ionising radiation
o Expensive (including the tracer itself)
o Modest spatial resolution
o Snapshot

Question 12

what is fMRI

Answer 12

• BOLD (blood-oxygen-level dependent) signal
• Different levels of oxygenated haemoglobin
• Voxel measurement (3D pixel)

Question 13

how many neurons and glia in 3mm voxel?

Answer 13

2 million neurons and 2 million glia

Question 14

how many neurons and glia in 1mm voxel?

Answer 14

72000 neurons and 72000 glia

Question 15

strengths of fMRI

Answer 15

o Functional, in real-time
o Good spatial resolution
o No radiation

Question 16

weaknesses of fMRI

Answer 16

o Poor temporal resolution
o Subject is restricted
o Aversive environment

Question 17

what is EEG

Answer 17

• Electrical activity measured in the cerebral cortex (synchronous activity of cortical neurons)
• Groups of neurons firing together (not really AP)
• Characteristic ‘waves’ (oscillations; temporal rather than spatial)

Question 18

strengths of EEG

Answer 18

o Good temporal resolution
o Non-invasive
o Cheap

Question 19

weaknesses of EEG

Answer 19

o Poor spatial resolution
o Only measures activity on the brain surface
o Artefacts

Question 20

waves in EEG from most to least alert

Answer 20

gamma
beta
alpha
theta
delta

Question 21

gamma waves

Answer 21

30-100Hz
insight, learning, problem solving

Question 22

beta waves

Answer 22

12-30Hz
active thinking, alertness, scrolling

Question 23

alpha waves

Answer 23

8-12Hz
relaxation
meditation

Question 24

theta waves

Answer 24

4-8Hz
daydreaming, intuition, creative thinking

Question 25

delta waves

Answer 25

0.5-4Hz deep sleep, recovery, unconsciousness

Question 26

what wave is this: 0.5-4Hz deep sleep, recovery, unconsciousness

Answer 26

delta

Question 27

what wave is this: 4-8Hz daydreaming, intuition, creative thinking

Answer 27

theta

Question 28

what wave is this; 8-12Hz relaxation meditation

Answer 28

alpha

Question 29

what wave is this: 12-30Hz active thinking, alertness, scrolling

Answer 29

beta

Question 30

what wave is this: 30-100Hz insight, learning, problem solving

Answer 30

gamma