Visual Perception Flashcards
photoreceptors
specialized neural cells that respond directly to the incoming light
rods
- Colourblind
- Sensitive to very low levels of light
cones
- Colour
- Need brighter light
- 3 types sensitive to different wavelengths (combination of activation = colour seen)
- Fines detail (acuity)
acuity
Ability to see fine detail
fovea
very centre of the retina
bipolar cells
- On retina
- Stimulated by rods and cones
ganglion cells
- On retina
- Stimulated by bipolar cells
- converge to form the optic nerve
lateral geniculate nucleus (LGN)
- a way station in the thalamus
- receives information from the optic nerve
- sends information to the occipital lobe
single-cell recording
a procedure through which investigators can record, moment by moment, the pattern of electrical changes within a single neuron
centre-surround cells
Firing rate:
1. goes up if hits centre
2. goes down if it hits the outer areas
3. stays much the same if it hits half-half
edge detector cells
- Different ones prefer different orientations but fire to some degree for all
- Help us see the edges
binding problem
how to put the pieces back together after parallel processing
2 solutions to the binding problem
- Visual maps (spatial position)
- Neural synchrony (firing synchrony)
form perception
perception goes beyond the information you see
simplicity
when things appear similar to each other, we group them together and tend to think they have the same function.
proximity
when things are close together, we group them together
distance cues
features that indicate the position of an object
binocular disparity
the difference between what each eye sees - one distance cue
