Color perception Flashcards
Lateral Geniculate Nucleus layers
Magnocellular and parvocellular
LGN: Magnocellular layer
The inner two layers, transmit info necessary for perception of form, movement, depth, and small differences in brightness
LGN: parvocellular layer
Outer four layers, transmit info necessary for perception of color and fine details
Primary visual cortex
combines info from ganglion cells, allows for detection of features larger than visual field, modularly divided, like feature detectors. Individual features and characteristics
Extrastriate cortex
combines info from the modules to form perception and entire visual field; orientation, movement, spatial frequency, retinal disparity, and color. Puts the information together
Two pathways of the extrastriate cortex
dorsal and ventral stream
Dorsal stream
where pathway, recognizes movement, guides navigation
Ventral stream
what pathway, recognizes objects and colors, size, shape, color, texture
Trichromatic theory
the eyes contain 3 cones that are sensitive to a spec. hue or color. Absorption pathways are determined by the different wavelengths. (Short-blue) (medium-green), (long-red)
Protanopia
red and green hues are confused. Red cones filled with green opsin and leads to difficulty seeing red
deuteranopia
red and green hues are confused. Green cones are filled with red opsin and leads to difficulty seeing red.
Tritanopia
lacks blue cones, normal red green vision
Opponent-processing theory
color perception occurs after the light is received by cones and then transmitted to ganglion cells. Color is represented as opponents (red vs green and yellow vs blue)
Perception of form
starts with neurons in the striate that are sensitive to orientation and spatial frequency, then sends info to the V2 region which is relayed to the subregions of the visual associate cortex that make up the ventral system.
Visual Agnosia
damage to the extrastriate. Inability to perceive or identify a stimulus although the details can be perceived
