W5L1 - fMRI Research 1

Question 1

Recap of W4: What and why do we see with fMRI scans. How is it analysed

Answer 1

Local activity in scans because signal quality is better due to oxygenated blood

Statistical Parametric Mapping:
General Linear Model is usually fitted to brain activity at each voxel

Question 2

Recap of W4: BOLD Signal. What does it tell us

Answer 2

• BOLD measured while participants engage in a cognitive task
• Repeated measurement of brain activity is required for the whole brain because signal noisy
• Differences in BOLD signal tell us something about whether a brain regions ‘is engaged’ in the task

Question 3

Localising cognitive functions: Kanwisher et al. (1997) and the Fusiform Face Area (FFA). What was it contrasted with. How are the findings

Answer 3

Faces > Objects
Faces > Scrambled Faces
Faces > Houses
Faces > Hands
Activation in FFA

Great example for a well controlled experiment. Reliable in most participants and replicable.

Question 4

Other modules found other than FFA

Answer 4

Parahippocampal Place Area (PPA): Houses & Places

Extrastriate Body Part Area (EBA): Body

Question 5

1st Argument against Modulaity. Gauthier & Tarr (1997)

Answer 5

After greeble expertise, FFA responded to greebles. FFA reflecting expertise.

Question 6

2nd Argument against Modulaity. Malach et al. (2002)

Answer 6

Visual system not by specific object categories; but by where in objects are usually encountered (Cortical topography/eccentricity)

Coding driven by resolution needs:

(1) High Resolution = Centre = Faces = FFA
(2) Peripheral Resolution = House/Place = PPA (that’s where places/houses usually are encountered in our visual field )

Question 7

Modularity, Expertise and Eccentricity

Answer 7

Evidence for all 3 - true to some extent.

fMRI signal might therefore reflect a mixture of all three coding schemes