fMRI

Question 1

Spin Echo Imaging

Answer 1

fMRIs use a type of T2 weighted imaging where the brain is imaged in 3s

Question 2

Heeger and Ress (2002)

Answer 2

fMRIs work because oxy and deoxyhaemoglobin have different magnetic properties so can be separated in images (more O2 means more magnetic)

Question 3

BOLD

Answer 3

blood oxygenation level dependent signal - standard form of slight dip then positive overshoot (overshoot is what we measure)

Question 4

Siero et al (2014)

Answer 4

BOLD is a indirect measure of neuronal activity, but shows strong correlations

Question 5

Temporal Resoltion

Answer 5

BOLD reflects the post-synaptic resetting of neurons as they need oxygen to move ions against their conc. gradients so there is a time lag of 3-5s

Question 6

Spatial Resolution

Answer 6

limited because imaging in 3s but can be overcome by overlaying onto structural image, limited because of oversupply of 02 means oxygenated blood covers more brain regions than are actually active

Question 7

Walter et al (2007)

Answer 7

fMRIs show that under high cognitive load depressed individuals have overactive dorsolateral prefrontal areas linked to compensating for diminished executive function

Question 8

Matthews et al (2006)

Answer 8

fMRIs can be used in pre-surgical mapping so show which areas to avoid in order to maintain function, but doesn’t account for upstream activity

Question 9

Davitakos et al (2005)

Answer 9

multivariate pattern analysis can be used to differentiate the brain activity when lying or telling the truth with 89% accuracy (when training on 21Ps, testing on 1Ps)

Question 10

Field et al (2007)

Answer 10

brain regions active during specific driving tasks: steering errors are left superior parietal lobe, future path info is superior parietal cortex

Question 11

Smith et al (2015)

Answer 11

fMRIs on stroke patients to see how they respond to hazards whilst driving