Localising cognitive functions fMRI: L9

Question 1

we can use fMRI to study what about the human visual system?

Answer 1

study the transformation of visual content as it becomes available to higher-level visual areas in the cortex

Question 2

Kanwisher investigated?

• presented participants with?
• compared?

Answer 2

how faces are represented in the brain
- images of faces & contrasted BOLD signals to when participants saw objects

(faces>objects)

Question 3

Kanwisher

-results

Answer 3

• a region in the fusiform gyrus responding more strongly to faces than to objects

Question 4

what did Kanwisher do to rule out that this was simply due to using objects as a control category?

Answer 4

different control category was used: scrambled faces

faces>scrambled faces

Question 5

Findings of faces > scrambled faces

Answer 5

same as initial findings, the same brain area was strongly activated for faces

Question 6

Kanwisher 3rd condition (houses)

- results

Answer 6

faces > houses
- region in fusiform gyrus showed stronger activation for faces

-> maybe this region processes body parts in general? = no, faces >hands same result

Question 7

what was this brain region named due to these results?

Answer 7

fusiform face area (FFA) bc they believed it was the brain’s “module” for face processing

Question 8

other modules have been discovered in the visual brain (4)

Answer 8

1. FFA
2. parahippocampal place area - PPA (houses and places)
3. extrastriate body part area -EBA
4. some regions specialised for letters/tools/animals

Question 9

the Kanwisher study was a …?

Answer 9

well controlled experiment

Question 10

arguments against kanwisher experiment (2)

Answer 10

• the brain can’t be made up of modules (it would run out of space)
• maybe it only looks like this region is specialised on faces

Question 11

Gauthier study

• asked participants to?
• what did participants learn?

Answer 11

• distinguish between different types of greebles (faceless figures)
• family structures of the greebles and became experts in identifying them

Question 12

what happened when

1. participants weren’t experts
2. when experts
   - > what does this mean about the FFA?

Answer 12

1. FFA responded more strongly to faces
2. FFA also responded highly to greebles
   - > activation in FFA might reflect expertise

Question 13

Malach argued?

Answer 13

the visual system might not be organised by specific categories but by WHERE in our visual field objects are usually encountered

Question 14

organisation in ventral visual cortex might follow what?

Answer 14

cortical topography i.e. eccentricity mapping

Question 15

what did Malach argue?

• faces (FFA)
• places/houses (PPA)

Answer 15

• coding is driven by resolution needs
• FFA = high resolution
• faces are encountered in the centre of our vision therefore we need a high resolution to recognise them
• PPA is used for processing the periphery as this is where houses are typically encountered in our visual field

Question 16

which coding system is correct?

Answer 16

• evidence for all 3, all might be true to some extent

- the fMRI signal might reflect a mixture of all three coding schemes