Exam 2 Flashcards
perception = ___ + ___
sensation + prediction based on experience
our visual systems quickly and efficiently represent the world with limited ___ by making use of lots of past ___
limited information ; past experience
what we perceive is a ___ of what comes into our senses, guided (or biased) by what we have seen most often in our lifetime
construction
we have so much experience viewing ___ that our visual systems can sometimes lead us to perceive anything with many face-like features as being a face, at least momentarily
faces
the visual system develops over ___ to become efficient at classifying things commonly around you
childhood
photoreceptors that are sensitive to brightness
rods
photoreceptors that are sensitive to color
cones
the ___ is concentrated with cones
fovea
central fixation of the fovea
0 degrees
rods dominate ___
peripheral vision
pathway to cortex:
- retinal input
- ‘crosses over’ at the chiasm
- left or right visual field is processed in the opposite lateral geniculate nucleus (LGN) of the thalamus and occipital cortex
the ___ is a “first order” thalamic nucleus
lateral geniculate nucleus (LGN)
the right visual field is processed solely in the ___ primary visual cortex (V1), and vice versa
right visual field - left primary visual cortex
left visual field - right primary visual cortex
the lateral geniculate nucleus (LGN) is a component of which part of the brain?
thalamus
the LGN of the thalamus transfers retinal input to ___ in successive stages
V1
when transferring retinal input from the LGN to V1, first, a coarse “gist” of the scene is sent, followed by the fine details over the next ~___ms
~10 ms
slow, detailed (“specific”)
parvo
fast, coarse (“global”)
magno
the primary visual cortex (V1) is located along the ___ fissure
calcarine fissure
the primary visual cortex (V1) receives retinal input according to the ___ of the stimulus in the visual field
location
the ___ half of your visual field is routed to right V1
left
the ___ field areas are routed to the inferior back of V1
upper field areas
the ___ fixation point is routed to posterior V1
central fixation point
___ areas route to anterior V1
peripheral areas
for every degree of the visual field, separate clusters of V1 neurons are sensitive to different ___ (edges, contrast, brightness) of objects in that location
visual features
despite considerable differences in our left and right eye’s visual field, we see ___ image
one unified image
the mystery of binocular vision: each of our eyes sees a different view, yet the image we see is uniform
how is this “convergence” accomplished?
we haven’t figured it out exactly
why do we have two eyes? there is a consistent difference across prey/predator species in ___ vs. ___ processing
peripheral vs. depth processing
___ overlap in visual field (both eyes facing ___) gives a much better account of our distance to the object
wide overlap ; both eyes facing forward
prey eyes vs. predator eyes
prey eyes - stronger peripheral vision
lateral geniculate nucleus (LGN) directs left and right visual input to V1, but keeps track of which eye the retinal input came from in layer ___
layer 4
if we present conflicting information into each eye, our perception switches back and forth between the two
binocular rivalry
according to binocular rivalry, there must be some ___ and ___ between left and right eye input, reflecting ‘higher order’ (late visual cortex and prefrontal cortex) processes that bias our perception toward one stimulus
competition and choice
binocular rivalry task: when presented a happy face, a neutral face, or an unhappy face, people have a slightly greater likelihood of reporting an __ face than a ___ face
emotional face ; neutral face
the visual system converts the light at the retina into the basic properties of visual perception including: (5 components)
- lightness
- color
- depth
- size
- motion
___ qualities can be different from the physical properties of visual stimuli as measured by purely objective methods (ex. was the dress white and gold or blue and black?)
perceived
lightness is a ___ quality, while luminance is a ___ property of an object
perceived quality ; physical property
the ___ of an object is not directly related to the ___ of an object
lightness ; luminance
lightness could be described as a ___ value, dependent upon local ___ and prior ___
calculated value ; local context ; prior experience
our visual systems have not evolved to determine the “___” nature of stimuli, only what we need to manage
“true”
through infancy and early childhood (by ___ and ___) we learn what visual features are “correct” and use this information to interpret future scenes
trial and error
around what age do we learn what visual features are correct?
around age 3 or 4
a global distinction can be made between “___” and “___” visual pathways, although recent data suggests the streams are more mixed
“what” and “where” pathways
two pathways within the primary and extrastriate visual cortex:
where pathway and what pathway
where pathway - ___ stream
dorsal stream
analysis of motion and spatial relations within this pathway
where pathway
what pathway - ___ stream
vental stream
analysis of form and color within this pathway
what pathway
ventral visual cortex: early vs. late stage:
a rough distinction can be made between early visual (“___”) and later visual (“____”) processing regions
(“simple”) and (“complex categorical”)
which part of the brain is utilized during late stage?
inferior temporal (IT) visual cortex
which part of the brain is utilized during early/mid stage?
occipital visual cortex (V1, V2, V3…)
visual cortex - general locations:
this part of the brain is medial inferior temporal
parahippocampal gyrus
visual cortex - general locations:
this part of the brain is lateral inferior temporal
fusiform gyrus
visual cortex - general locations:
this part of the brain is referred to as the “transition area”
lateral occipital
visual cortex - general locations:
this area of the brain is middle temporal
area MT
early/mid stage of visual processing occurs within:
V1, V2, V3, V3a
‘early stage’ :
‘late stage’ :
‘early stage’ : V1, V2, V3
‘late stage’ : everything else
PPA refers to:
parahippocampal “place area”
FFA refers to:
fusiform “face area”
lots of fMRI and invasive data reveals that there are multiple ventral visual regions dedicated to the processing of ___ of things like faces, body parts, words, and others
categories
where is color perceived?
lesion data suggests that color perception depends on regions of ___ visual cortex, a late stage of visual processing
ventral visual cortex
patients with damage in the ventral visual cortex (stroke, tumor) often report a ___ loss of color vision, while other visual abilities remain intact
specific
depth cues
V1 activity at central fixation, representing a small object activates:
only V1 and V2
V1 activity at central fixation and periphery, representing a large object activates:
V1-5
the illusory effect in V1 depends on feedback from ___ brain regions
because fMRI reflects average activity over seconds of time, we can see this ___ effect in V1
later brain regions ; context effect
in the ___ (a type of monkey), the organization and timing of visual processing stages is relatively well known
macaque
visual information is integrated and resolved along the ventral pathway until task-driven decisions can be made in PFC around ~___ ms
~150 ms
the first stage of visual processing in V1 is purely ___ driven (“___”)
stimulus driven ; (“bottom up”)
the first stage of visual processing in V1 occurs up to around ~___ ms after cue onset
~50 ms
