lecture 7 - failures of recognition- agonosia and prosopagnosia

Question 1

object recognition and what we can solve

Answer 1

-competing issues
-generalisability- have the ability to recognise objects
-specificity - have ability to recognise and distinguish similar items to be different

Question 2

early views of object recognition
Marr model

Answer 2

-solves the visual problem
-has details how we go from the 2d image on the eye to a 3 dimensional representation in the brain
-says we go through a series of steps

-alot of textbooks mention this however this isnt really object recognition it’s more about 3d construction in brain

-the recognition part of the model is the last bit ‘categorisation’

Question 3

when object recognition fails
-patients with issues patient GL

Answer 3

Lissauer (1890) - patient GL
-head injury patient (got blown against a fence in storm)
-when he woke up he had problems in understanding recognising objects
-he would reach inside paintings to get things out
-wasn’t intellectually impaired
-no other peception issues

• Associative agnosia

Question 4

visual object agnosia
-freud
-features
*modality specific
*category specific

Answer 4

• Freud (1891): first used term agnosia

-this is a modality specific condition
-visual object agnosia is specific to vision- they can still recognise objects using other sense (can get object agnosia in other senses)

• can be category specific
  -tends to be they have a problem recognising man made objects or a problem recognising natural objects (or living things)
  -showed video where he says he knows what the object is but he cant name it

Question 5

visual object agnosia
2 subtypes (Lissauer)
-apperceptive agnosia
-associative agnosia

Answer 5

both cant identify objects, but how they can’t is different

apperceptive agnosia
-cant identify objects x
-can describe features
-cant match by appearance x
-cant match by function x
-cant copy drawings x
-can draw from memory

can tell you things about the object etc colour, but cant understand how the individual components of the object fit together

associative agnosia
-cant identify objects x
-can describe features
-can match by appearance
-can’t match by function x
-can copy drawings
-cant draw from memory x

Question 6

apperceptive vs associative agnosia
-performance in task

-match appearance
-match by function

Answer 6

appearance task
-see two images side by side (object in different angles) - have to decide whether it is the same object or not

-in apperceptive agnosia , the patient can’t do this task, they can describe the features but dont understand what the object is

-in associative ,they can can describe features and piece together the features into an object but can’t name it., so can tell you its the same object but can’t tell you what the object is

matching by function
-get a picture, and you need to match it to one of the pictures above with the same function

-people with apperceptive agnosia will pick randomly between the two photos because they cant understand the 3d structure of any objects

-in associative agnosia , they fail this task as well but differently, theyll match the object to the one with the closest 3d structure to the one they get given

Question 7

-apperceptive vs associative agnosia
-copy drawings

Answer 7

apperceptive
-will struggle to copy the drawing
-they understand the components of an object but can’t see how it makes a whole (eg copying ‘X’ they draw two lines but not in thr right arrangement

associative
-can copy drawings,but don’t know what theyre drawinf

Question 8

apperceptive vs associative agnosia
-drawing from memory

Answer 8

apperceptive
-can draw well from memory
-do it be drawing fragments at a time (not a normal way

associative
- can’t draw well from memory

Question 9

what are the damage sites in apperceptive vs associative agnosia

Answer 9

apperceptive
Unilateral right hemisphere
damage. Right inferior parietal lobe

associative
Usually bilateral. Crucial area
thought to be left hemisphere. More ventral than apperceptive damage

Question 10

what is Warrington’s anatomical model

Answer 10

Warrington (1985) proposed 2-stage (anatomical) model based on pathology of agnosia
-object recognition works through steps:
-initial visual processing in occipital lobes
-then info gets passed to right hemisphere ,where perceptual categorisation goes on
-taking the raw featural image and turning it into a 3 dimensional understanding in the brain
-then this is passed on to the left hemisphere , where semantic categorisation happens, linking it to your stored knowledge and being able to name object

• Extended and constrained existing
  theory
• Provides testable predictions

Question 11

Warrington’s anatomical model
-apperceptive vs associative agnosia

Answer 11

apperceptive agnosia
theorised that in apperceptive agnosia, the perceptual categorisation in the right hemisphere is damaged

-by disrupting that flow of information,you cant construct the 3d model but you also cant pass info into the semantic cetegorisation
-but since that bit is intact if you try access it directly through memory yiu can acess it

associative agnosia
the damage is in the semantic area

Question 12

two types of agnosia - continuum?

-evidence it is a continuum rather than 2 different conditions
-evidence there are many types instead

Answer 12

Continuum? With apperceptive as a more severe form than associative?
-suggests there isnt 2 forms its just different severities

• Lesion locations overlap a lot
• Progressive cerebral atrophy - symptoms progressed from associative to apperceptive (De Renzi 1986)
• Other subtypes identified that do not fit typical distinction (e.g., integrative agnosia: Riddoch and
  Humphreys, 1987)

Question 13

prosopagnosia

Answer 13

-can’t recognise faces
-range of severities and symptoms
-people with propagnosia often recognise others by their clothes or hair etc

Question 14

prosopagnosia - where in the brain
-patient data

Answer 14

Damage to right fusiform
gyrus associated with
specific failure of face
recognition
(often called fusiform face area)

• Marotta, Genovese &
  Behrmann (2001)

Question 15

imaging face and object processing

Answer 15

The right fusiform gyrus (aka fusiform face area)
-pictures show difference in where brain is active when looking at objects/ faces

Question 16

behavioural evidence that object and face processing are different
-recognition tasks

Answer 16

-inversion effect
-what happens to recognition abilities when you turn things upside down

-typically when you turn an object upside down it isn’t too hard to tell what it is

-but with faces , it is much more difficult to tell,
-theorised this effect happens because the information we use to recognise faces is different than the info we extract from objects

Question 17

inversion superiority effect in prosopagnosia

Answer 17

-in healthy controls people recognise upright faces better than inverted

-for prosopagnosic patient, they recognise faces better when the face is inverted
(because the bit that’s disrupted is the ability to take out that overall configuration from the face , if you turn it upside down and disrupt that source of info anyway , it releases that problem)

Question 18

is prosopagnosia a separate
condition from agnosia?

Answer 18

If object and face processing are separate cognitive processes then we should be able to find dissociations between them in patients

-should be able to find patients with prosopagnosia and not agnosia and vice versa

• Easier to find cases of prosopagnosia without agnosia than agnosia without prosopagnosia

Question 19

prosopagnosia without
agnosia
WJ

Answer 19

WJ (51 yo male, 3+ previous
strokes)
* Became a farmer and bought
sheep after stroke (to use as therapy)
* Became good at recognising
sheep (even more than other sheep farmers) (but wasn’t good at recognising faces)

this was used as am argument that even though he had profound issues in recognising human faces, other categories of stimuli seem to be intact
-this also argues there’s something very different for human recognition in the brain

Question 20

prosopagnosia without
agnosia
RM

Answer 20

RM (male, b. 1932, aneurism
in 1989)

• Lost ability to recognise faces,
  preserved ability to recognise
  cars
• Test for cars: 210 image of
  cars. Report make, model and
  year (+/-2 yrs)
• RM: 172 correct
• 6 controls - best = 128

Question 21

agnosia without prosopagnosia

Answer 21

MH (72 yo female, general cortical
atrophy, no focal lesion)
-cant recognise objects, but can mostly recognise faces
* Naming line drawings
* MH score 7.15
* 20 controls score 14.14

• Face naming (celeb photos)
• MH 75% correct
• controls 84%
• MH within 1 SD of controls

Question 22

agnosia, prosopagnosia, double dissociation

Answer 22

MX (male, farmer)
* Lost ability to recognise faces,
places and livestock
* Face recognition recovered
(after 6 mo) but object agnosia didn’t

• Recognising his cows (object)
• MH score 2 of 15 (bad , was very affected
• co-workers (2): 10 and 14

compared

Mr W (54 yo male, farmer, right
parietoccipital lesion + bilateral occipital
lesions)

• Poor face recognition (see table)
• Fine at recognising own cows - but this is anecdotal evidence in the original paper (NO ACTUAL DATA for this)

Question 23

faces vs objects: distinct
impairments? distinct processes?

Answer 23

-this info would all argue there is a distinction

Evidence traditionally argued to favour distinction
* is it always the right fusiform gyrus as key for face processing
and recognition?
* Is this fair?

Question 24

Sites of damage in prosopagnosia:
not always right fusiform gyrus

Answer 24

Not always right fusiform gyrus

• Prosopagnosia with intact right
  fusiform gyrus (patient DF -
  Steeves et al., 2006)
• Left hemisphere (patient DN -
  Mattson, Levin & Grafman,
  2000)
• Bilateral (De Renzi and Di
  Pellegrino, 1998)
• WJ - bilateral occipital lesions,
  left parietal and temporal lesions

Question 25

Right fusiform gyrus and
non-face stimuli

Answer 25

-if the right fusiform gyrus was really only about recognising human faces , then it shouldn’t show activity for other forms of stimuli

right fusiform gyrus activity for cartoon faces
and cat faces (Tong et al., 2000)

Question 26

Congenital prosopagnosia
-also evidence that the conditions are separate

Answer 26

Problems with face
recognition from birth

• Show activation in right (and left) fusiform gyrus very like control participants (unlike aquired prosop patient)
• But fail to recognise faces

Question 27

faces vs objects: a fair
distinction?

Answer 27

it is a hard task
maybe we aren’t comparing like to like
* faces all very familiar - require fine within -class discrimination

• vast experience with faces
• expertise as the distinction between face and object recognition?

Question 28

dog inversion - expertise

Answer 28

toom category of peopel who have real expertise in a non face category

For dog breeders, decisions about the breed of a dog may be similar to
face recognition:

• fine within-class discriminations

-expertise with stimuli

-so argued that recognising faces isnt really about faces but about expertise

Question 29

testing expertise theory
greeble inversion

Answer 29

-created novel stimuli - a little creature like things, gave them names and charetersitics and theb looked at how people recognised it

used inversion effect
-at first when people didn’t know what these things were there they didnt have much difference at whether they were looking at the greebles the right or wrong way up

-then people were trained to become experts at recognising the greebles , and at the end this they started showing the inversion effect

Experts with Greebles show
inversion effect (but less so than
for faces

Question 30

expertise and inversion
-how many studies actually show this?

Answer 30

-the only two that show it are the dog and greebles one

Question 31

neural evidence - greeble

Answer 31

-is the fusifrom ‘face area’ really just for faces - this argues its the centre for expertise not faces

-greeble novices show no activity in right fusifrom gyrus

-greeble experts show right fusifrom gyrus activity

Question 32

idea of - expertise in the right fusiform gyrus

Answer 32

right fusiform gyrus as a ‘flexible fusiform area’ for fine within-class discrimination? (Tarr & Gauthier,
2000)

• BUT for an argument AGAINST expertise see
  McKone, Kanwisher & Duchaine (2007)

Question 33

expertise acquisition despite prosopagnosia

Answer 33

-if the right fusiform gyrus is a centre for acquiring expertise , and thats whats being disrupted in individuals with prosopagnosia
-then people who have damage to the right fusifrom gyrus , shouldn’t be able to become experts to recognising anything new
but this isnt true