Visual Perception (4) Flashcards
__________ - determines how far away objects are by making a clicking sound
Echolocation - determines how far away objects are by making a clicking sound
recall daniel kish from video in class
when did he become blind
Completely blind (retinoblastoma), has never seen anything in his life
recall daniel kish from video in class
He used a different _______ to gather information for his _______ ______
He used a different stimulus to gather information for his visual perception
Experiment: Blind Echolocation and FMRI
when did they lose their vision
Participant EB
Participant LB
Participant EB - lost their visions early on
Participant LB - at 14 years old
Experiment: Blind Echolocation and FMRI
how did exprimentors reconcile the fact that P’s cannot echolocate in FMRI machine
recorded P’s echolocating, and then played it back to them
Experiment: Blind Echolocation and FMRI
differentiate between participant EB and LB’s experiences
why were they different
Participant EB’s: almost the same as a sighted individual - activation in primary visual cortex
Participant LB - less activation in the primary visual cortex, still some in PVC
Why? Less neuroplasticity when they went blind
Experiment: Blind Echolocation and FMRI
Suggests that the brain is ________ , but not in the same way for everyone
specialized
explain “brain as a computer” metaphore
The brain is seen as the hardware, cognitive operations as the software
Describes the relationships between brain functions and structure
explain “hydraulic metaphor”
Descartes model of the brain where neural functions are governed by tubes carrying “spirit” or bodily fluids
the hydraulic metaphore lead to conceptual metaphors used today
give 3 examples
We think of information “flowing”, in the same way fluid does
The “stream of consciousness”
“waves of anxiety”
“deep thinking”
ideas that “come to the surface”
and memories that come “flooding back” when you encounter an old friend
Visual perception can be divided into an early phase and a later phase
define them
Early Phase - shapes and objects are extracted from the visual scene
Later phase - the shapes and objects are recognized
flow of information from the outside world to the internal mental world is known as???
sensation and perception
S&P has to do with
_______ stimulus - anything outside your body
_______ stimulus - the activation on the sensors
Distal stimulus - anything outside your body
Proximal stimulus - the activation on the sensors
distal and proxmial stimulus occurs via ______ _______
sense receptors
(eyes, skin, ears)
define low level vision
Initial processing of basic visual features through bottom-up processing automatically
define high level vision
The interpretation and recognition of complex visual features
through top-down processing
requires the complex parts of the brain like the prefrontal cortex
General Steps of Visual processing:
______ _____ enters
_______ are detected
_______ sketch is created
_____ sketch created
______ sketch created
Objects are recognized
Light energy enters
Features are detected
Primal sketch is created
2.5D Sketch created
3D sketch created
Objects are recognized
the primal sketch is the incorportation of ______ and ______
incorporation of edges and lines
________ occurs at he lowest level of bottom up processing
decompostion
define decompostion
breaking down complex visual information
As the input moves through the visual system gets ________ every time
condensed
Light enters the cornea, passes through eye and strikes _______ in the back of the eyes
retina
the retina contained the ______ and the _____ _____
fovea and the optic nerve
what is the function of the fovea
focuses things
focal point of retina when you look around
most sensitive, high quality part of the eye
what is the function of the optic nerve
Holds all of the fibres that connect sensors to other sensors
connects back to your primary visual cortex
_________ of _________ in retina contains receptors that react to light energy and charge it into electro-chemical energy
Network of Photoreceptors in retina
Millions of ______ are located near the outer edges of the retina
rods
differentiate between the purposes of rods and cones
rods detect dim light
cones deal with colour vision and acuity
______ have less sensitivity more resolution
______ have high sensitivity, low resolution
cones - Less sensitive more resolution
rods high sensitivity, low resolution
______ doesnt know wich of the 20 cells gave it information
this creates low ______
rods
acuity
______ - Connected to the next layer of bipolar cells at a ratio of 3:1
______ - Connected to the next layer, which are bipolar cells at the ratio 20:1
cones - Connected to the next layer of bipolar cells at a ratio of 3:1
rods - Connected to the next layer, which are bipolar cells at the ratio 20:1
Different cones are sensitive to different colours (wavelengths): name them
short
medium
long
short (blue)
medium (green light)
long (red light)
_____ are sensitive to light between blue and green
rods
explain intake direction of your left and right visual feilds
Left visual field info enters into right hand side of your cortex, and the same with the other side
______ _______ - visual field (the things you are perceiving)
_______ ______ - sensory information in the eye, from the distal stimulus
Distal stimulus - visual field (the things you are perceiving)
Proximal stimulus - sensory information in the eye, from the distal stimulus
where are left and right visual feilds consolidated
consolidated in the left and right geniculate nucleus (RGN and LGN)
At each step of the visual pathway, cells have receptive fields
what are receptive feilds and give an example
the pattern of light energy that the cell responds best to
On-centre and off-centre cells
