fMRI

Question 1

What are the advantages of fMRI?

Answer 1

• It allows us to study cognitive and affective processes in the brain
• Non-invasive, low risk
• High spatial resolution

Question 2

What are the disadvantages of fMRI?

Answer 2

• Hostile environment: Loud, narrow space
• Many exclusion criteria (pregnancy)
• Low temporal resolution

Question 3

What happens during the BOLD effect?

Answer 3

• Cerebral blood flow increases
• Cerebral blood volume increases
• Cerebral blood oxygenation increases
• T2* therefore measures the relative ratio of deoxyhaemoglobin concentration.

Question 4

What is the haemodynamic response function (HRF)?

Answer 4

HRF is the predicted BOLD response to an instantaneous neuronal signal.

Question 5

What is the standard fMRI experimental design?

Answer 5

• Participants in a scanner perform a task/ are presented with at least two stimuli.
• At least two conditions (subtraction logic)
• Take functional image of the entire brain every 0.8-2 seconds:
• T2* weighted (relatively low resolution 2-3mm voxel size)
• Approx 30-60 mins of data collection
• Take T1 weighted high res structural image for registration

Question 6

What are the two main designs for fMRI experiments?

Answer 6

• Block design

* Event-related design