the different sensory cells in the eye **
- photoreceptors (rods and cones)
- bipolar cells
- ganglion cells
the steps in information transfer from visual sensory cells to the visual cortex
sensory receptors in retina (photoreceptors, bipolar cells, ganglion cells) —-> sensory thalamus (LGN) —-> primary sensory cortex V1 (simple and complex cells) —–> sensory association cortex (dorsal, ventral stream, face recognition)
photoreceptors **
- rods (retina) and cones (periphery)
- turn photons into electrical signals
receptive fields **
- the particular region of sensory space in which a stimulus will modify the firing of that neuron
- receptive fields get bigger as process becomes more complex
what receptive fields for visual information in V1 encode **
- simple cells: sensitive to the orientation of light only
- complex cells: sensitive to both orientation and motion of light
how retinas create color receptive fields **
- through cones
- red, blue, green
**receptive field is illuminated with the color shown = firing increases
- *receptive filed is illuminated with the complementary color = firing decreases
- red light: stimulates red cone
- green light: green cone
- yellow light: red & green, but not blue
- blue light: blue cone & inhibitor of yellow-blue ganglion cell
bipolar cells *
neurons that receive messages from the visual receptors
-located closer to the center of the eye, send messages to the ganglion cells
ganglion cells **
aggregates across bipolar cells and transmits info to the brain
magnocellular cells
- layers 1 and 2
- contain info from rods
- non color sensing
- 4C(Alpha)
parvocellular cells
- layers 3-6
- contain from from cones
- color sensing
- 4C(Beta)
koniocellular cells
- in between layers
- contain info from blue-sensitive cones
- color sensing
- inputs to 2 and 3 layers
