Visual Perception Flashcards
The Eye
- Cones
- Rods
- Retinal Ganglion
- retina-geniculate-striate
CONES
- color and detail
- located in the fovea
- require a lot of light to function
*provide basis for colour vision
RODS
- vision in dim light
- located in the periphery
- muito mais do que cones
- nao distingue cores
Retinal Ganglion cells
recieve imput from cones and rods
retina geniculate striate
transmits information through the lateral geniculate nuclei (LGN) to the brain
Receptive field
regiao da retina na qual o estimulo visual influencia a firing rate dos neuronios
INHIBITORY - diminui firing rate
EXITATORY - aumenta ganglion firing rate
ON center ganglion cell
aumenta a taxa de firing qdo tem luz no seu centro e diminui qdo q a luz esta direcionada nas bordas
se ficar “meio a meio” nao tem resposta do neuronio
OFF center ganglion cell
diminui o firing rate qdo tem luz no centro e aumenta qdo tem luz nas bordas
se ficar meio a meio, nao tem resposta do neuronio
Lateral Inhinition
Lateral inhibition, melhora os visual edges. Qdo a luz afeta a RGC do meio de maneira mais forte e antes que as q estao do seu lado se ativem, elas sao inibidas pelo sinal da do meio.
From the eye to the Brain
- sinais que vao para o left vistual cortex vem do left side das duas retinas
- sinais que vao para o right side of the visual cortex vem do right side das duas retinas
Lateral Geniculate Nucleus (LGN)
- recieves imputs from the retina and projects to the primary visual cortex
- Magnocelular layer- form, movement, depth, brightness
- Parvocelular layer- colour and fine details
- topographical mapping
Striate Cortex
- V1 and V2 - early stages of visual processing.responsive to colour and form
- V3 and V3a - form in motion (but not colour)
- V4- colour and line orientation
- V5 - visual motion
Two visual pathways
P Pathway - ventral pathway - WHAT- form and colour processing (object regonition)
M Pathway - dorsal pathway - HOW - motion processing
there are extensive interaction between the two pathways
