THE SEEING BRAIN (exam 3)

what forms the optic nerve

axons of retinal ganglion cells bundle together to form the optic nerve

types of bipolar and ganglion cells and receptive fields

on center and off center bipolar and ganglion cells with center-surround receptive fields

what is the lateral geniculate nucleus

a structure in the thalamus that relays and organizes visual information from the retina to the primary visual cortex

parvocellular and magnocellular pathways

parvocellular processes color and fine detail magnocellular processes motion and coarse patterns first separate in the lateral geniculate nucleus

types of cells in v1

simple cells complex cells and hypercomplex end stopped cells

visual processing routes

retina to optic nerve to optic chiasm to optic tract to lateral geniculate nucleus to primary visual cortex v1 to extrastriate visual areas

patterns of blindness from v1 damage

scotomas contralateral visual field loss and cortical blindness

what is blindsight

the ability to respond to visual stimuli without conscious awareness due to damage in v1

processing after v1

information spreads to extrastriate visual areas along the dorsal and ventral visual streams

information in v4

color processing and complex form representation

information in v5

motion perception and movement processing

what is akinetopsia

motion blindness in which a person cannot perceive motion usually caused by damage to v5

stages of marrs model

primal sketch to two point five d sketch to three d model representation

agnosia mapping to marrs model

apperceptive affects early perceptual stages integrative affects combining features associative affects linking perception to meaning

apperceptive agnosia

inability to form stable perceptual representations making it hard to copy or match objects

integrative agnosia

ability to perceive parts of objects but inability to integrate them into a coherent whole

associative agnosia

ability to perceive and copy objects but inability to recognize or assign meaning to them

prosopagnosia

inability to recognize faces despite otherwise normal vision

face processing vs objects

faces are processed more holistically and involve specialized brain regions

bruce and young model

proposes separate processing pathways for facial identity expression and speech related mouth movements

haxby model

core face system including occipital face area fusiform face area and superior temporal sulcus plus extended regions for emotion and person knowledge

why face processing is special

faces require holistic processing and fine discrimination among very similar stimuli

face identification difficulty

faces require within category discrimination because faces are highly similar to one another

holistic face processing theory

faces are perceived as unified wholes rather than as separate independent features

within category discrimination

recognizing faces requires distinguishing among many similar items within the same category

expert object recognition

expertise with specific objects can lead to face like holistic processing strategies

greebles

novel objects used in experiments to study how expertise can create face like processing

collectible item discrimination

objects that must be distinguished from similar items rely on within category discrimination

thatcher effect

distorted facial features are difficult to notice when a face is inverted showing the importance of holistic processing

visual processing and mental imagery

mental imagery activates many of the same visual brain areas used in actual perception