visual systems (e2) Flashcards
(40 cards)
each type of receptor is specialized…
on a specific type of energy
vision
light —> electromagnetic energy
audition
pressure changes in the air
touch
pressure changes in skin
smell and taste
chemicals
transduction
energy is changed into electrical signals for the brain to read
- occurs in receptors
- retina in the eye
retina
neural tissue that receives light
fovea
small area specialized for active, detailed vision
periphery
has better sensitivity to dim light
the retina has two types of receptor cells
rods - in periphery
cones - mostly in fovea
geniculostriate pathway
pattern, color, and motion recognition
visual-form agnosia: inability to recognize objects
what areas is the geniculostrate pathway in?
lateral geniculate nucleus, striate cortex
tectopulvinar pathway
tectum: mibrain, superior colliculus, thalamus pulvinar nucleus, parietal lobe
what areas is the tectopulvinar pathway in?
superior colliculus, pulvinar
spatial location of objects…
unconscious
pathways
groups of neurons that send and receive messages
visual ataxia
inability to recognize where objects are located
easier perceived when object is moving
V1 (primary visual or striate cortex) and V2
functionally heterogenous areas
most specific functions of areas in
occipital lobe
V4
important for color vision
damage results in loss of color cognition
V5 (middle temporal, MT)
important to perceive objects in motion
damage allows people to see objects at rest, but when they begin to move, object vanishes
all visionary info transferred to output area…
frontal lobe
2 pathways
what (ventral)
where (dorsal)
what pathway
ventral
lower
towards temporal cortex
prosopagnosia
agnosia