perception and action Flashcards
what are the two visual streams
dorsal and ventral
define the dorsal stream
v1 > v2 > v4 > mid temp. cortex > posterior paretial/superior temporal
control of movement and motion processing
define the ventral stream
v1 > v2 > v4 > inferior temp, angular gyrus and limbic system
object recognition, language processing, memory and emotion
what does v1 mean
primary visual cortex
ventral known as
what pathway
dorsal known as
where pathway :(dorsal fin UP )
what disorders is the ventral stream related to
visual agnosia
prosopagnosia
achromatopsia
what disorders is the dorsal stream related to
motion blindness
define visual agnosia
impairment to ventral streams = cant identify objects
fail to visually recognise
not due to memory or visual loss
damage to occipital lateral cortex correlate with recognition problems
explain patient DF visual agnosia
cant recognise or report orientation
hand able to orient correctly
can direct action (dorsal) but not recognise how (ventral)
explain patient GS visual agnosia
cant name obects but can describe from memory and identify using other senses
requires additional contextual info to aid identificaition
describe achromatopsia
damage to HV4 located in V1 causes colour blindness
not due to cone loss or imbalance
what area is linked to face processing
superior temporal sulcus
what evidence supports that the STS is involved in face processing
gross et al 1969
specific neurons respond only to faces
perrett et al 1994
response to faces in this area at least x2 and up to 10x greater than to other 3d objects
define prosopagnosia
the inability to recognise faces, often due to stroke or brain injury
supports that right fusiform face area involved primarily in face processing
