Vision Flashcards by Melissa Head

What are the 2 visual receptor cells in the retina?

cone cells
rod cells

How well did you know this?

Not at all

Perfectly

Where is the retina?

at the back of the eye

How well did you know this?

Not at all

Perfectly

Where do impulses from the retina leave the eye via?

the optic nerve

How well did you know this?

Not at all

Perfectly

What are cone cells?

sensitive to colour and detail perception

How well did you know this?

Not at all

Perfectly

Where are cone cells located?

in the fovea (central part of retina)

How well did you know this?

Not at all

Perfectly

What are rod cells?

used for dim light
sensitive to light levels

How well did you know this?

Not at all

Perfectly

Where are rod cells located?

in the periphery (edges of visual field and retina)

How well did you know this?

Not at all

Perfectly

What cell receives input from cones and rods?

retinal ganglion cells

How well did you know this?

Not at all

Perfectly

Is central retina cone dominated or rod dominated?

cone dominated

How well did you know this?

Not at all

Perfectly

Is peripheral retina cone dominated or rod dominated?

rod dominated

How well did you know this?

Not at all

Perfectly

What is the process of reception?

the absorption of physical energy (light) when it hits the retina

How well did you know this?

Not at all

Perfectly

What is the process of transduction?

the absorption of light which is then converted into electrochemical patterns in neurons (electrical signals) that reach the brain

How well did you know this?

Not at all

Perfectly

Which hemisphere does information from the left visual field go to?

right hemisphere

How well did you know this?

Not at all

Perfectly

Which hemisphere does information from the right visual field go to?

left hemisphere

How well did you know this?

Not at all

Perfectly

What is the retina-geniculate-striate system?

where information goes from the retina to the lateral geniculate nuclear (LGN) to then the striate cortex

How well did you know this?

Not at all

Perfectly

What is the primary visual cortex?

striate cortex

How well did you know this?

Not at all

Perfectly

What are the 2 parallel paths from retina to visual cortex?

parvocellular
magnocellular

How well did you know this?

Not at all

Perfectly

What is the parvocellular path?

sensitive to colour and fine detail
most input comes from cones

How well did you know this?

Not at all

Perfectly

What is the magnocellular path?

sensitive to motion
most input comes from rods

How well did you know this?

Not at all

Perfectly

Mather (2009): Visual cortical areas

box sizes reflect sizes of each brain region
arrows show proportion of fibres in each pathway
vertical positions of boxes indicate response latencies of cells

How well did you know this?

Not at all

Perfectly

What does Zeki’s functional specialisation theory discuss (1993, 2016)?

areas of the visual cortex in brain
assumed colour, motion, form are processed in anatomically separate areas

How well did you know this?

Not at all

Perfectly

Zeki: areas of visual cortex

V1 and V2
V3 and V3A
V4
V5 (MT in humans)
LOC
OFA
FFA

How well did you know this?

Not at all

Perfectly

What is V1 and V2?

basic / early stage of visual processing

How well did you know this?

Not at all

Perfectly

What is V3 and V3A?

respond to form perception (especially of moving stimuli)

What is V4?

colour and shape perception

What is V5?

motion perception referred to as MT in humans

What is LOC?

object perception

What is OFA and FFA?

face perception

What is a strength and weakness of Zeki's theory?

ambitious and influential more complex than assumed as V1 is connected to at least 50 other areas binding problem still remains unsolved

What is Milner and Goodale's perception-action model (1977)?

believe there is 2 visual pathways ventral stream and dorsal stream

What is the ventral stream?

the "what" system vision for perception (controls perception)

What is the dorsal stream?

the "where" pathway Vision for action (controls action)

What are 4 differences between ventral and dorsal system?

ventral = allocentric, conscious, extension of parvocellular pathway, temporal lobes dorsal = egocentric, unconscious, extension of magnocellular pathway, parietal lobes

What does allocentric mean?

object centred

What does egocentric mean?

body centred

Visual illusions: Muller-Iyer Illusion

vertical lines actually being the same length

Muller-Iyer illusion findings (Bruno et al, 2008)

when pointing as a response to which line is longer (use vision for action) illusion size was 5.5% when verbalising a response (vision for perception) illusion size was 22.4% illusion requires ventral over dorsal

Ebbinghaus illusion

where both centre circles are same size but on on top looks larger than on at bottom due to circles surrounding it being smaller illusion greater with ventral (vision for perception) system

What stream is needed for grasping objects?

both the ventral stream (vision for perception) as well as dorsal stream (vision for action)

What are the strengths and limitations of Milner and Goodale's theory?

influential approach findings with visual illusions are variable But there are 2 dorsal systems (dorso-dorsal and ventro-dorsal)

What does hue mean?

the colour itself

What does saturation mean?

influenced by amount of white present determine if it's vivid or pale

What is the dual process theory? (Mather, 2009)

states there are 3 cone classes: red = long wavelength light green = medium blue = short provide input to 3 channels: - red-green - blue-yellow - light-dark

What does colour constancy mean?

perceived colour remains the same despite changes in wavelength in light source objects have intrinsic colour

What does chromatic adaptation mean?

refers to when sensitivity to illuminant (light source) of any given colour decreases over time

What is retinex theory? (Land, 1986)

observers compare light reflected from a surface against that reflected from opposite surfaces

What are some evaluation software colour constancy?

large individual differences are still poorly understood research focuses on artificial visual environments

What cues are used in depth perception?

monocular cues (using only one eye)

What are 3 examples of monocular cues?

texture gradient interposition motion parallax

What is interposition?

where nearer objects hide part of a more distant one

What is motion parallax?

movement in one part of retinal image objects that are closer appear to move faster than objecters further away

What enhances depth perception?

stereopsis allows us to see the environment 3-dimensionally very powerful at short distances only

What is amblyopia?

"lazy eye" have impaired stereoscopic depth perception

How is information from different cues combined?

- additivity (info from all cues combined) - selection (info from single cue is used others ignored) - weighting of cues (on more reliable ones)

What does size constancy mean?

object is still perceived as having the same size when presented at different viewpoints

What is the size distance invariance hypothesis?

perceived size is proportional (equivalent) to retinal size and perceived distance infer distance from depth cues

What is blindsight?

ability to respond to visual stimuli without conscious visual experience or awareness

What is type 1 blindsight?

no conscious experience

What is type 2 blindsight?

some residual awareness