Perception 2 - Visual Agnosia

Question 1

dorsal pathways

Answer 1

leading from V1 to the parietal lobe that is important for representing ’where’ things are

Question 2

Ventral Pathway

Answer 2

leading from V1 to the temporal lobe that is important for representing ‘what‘ objects are. Ventral system includes visual association areas

Question 3

damage to visual association areas

Answer 3

A person can ‘see’ – perceive colours, movements, understand that there is a meaningful object in front of him
BUT – fail to know or perceive WHAT (or who) that object is

Question 4

Prosopagnosia

Answer 4

Prosopagnosia is agnosia for faces
Sometimes called ‘face blindness’
Can be caused by brain damage to FFA or some people have milder version from birth

Question 5

agnosia

Answer 5

‘failure to know’
Impairment of visual perception due to brain damage, which is not attributable to sensory impairment or gross intellectual impairment

Question 6

division of visual agnosia

Answer 6

Lissauer (1890) distinguished:
Apperceptive Visual Agnosia
Associative Visual Agnosia

Question 7

Apperceptive Visual Agnosia

Answer 7

Patients do not gather elements together to make a ‘whole’
Vision groups elements together (individual lines, colours etc…) to interpret shapes and objects – this ability is lost

Question 8

Associative Visual Agnosia

Answer 8

Patients can ‘perceive’ the object – but can’t name it; they no longer associate it with the correct name
Recognition by touch and verbal description good

Question 9

Visual agnosia - famous case- HJA

Answer 9

Patient HJA (Humphreys and Riddoch, 1987)
This patient has elements of both ‘apperceptive’ and ‘associative’ agnosias
Unable to integrate – in order to make sense of it
Can copy (in 6 hours!) but not name