what is the role of the visual system?
to extract useful features from light signals to help guide animal behavior to optimize their survival and reproductive opportunities.
useful features - color, depth, motion, size
retina
back layer of the eyes containing a variety of cells and glia
made up of photoreceptors, RGCs, bipolar cells, horizontal cells, and amacrine cells
photoreceptors
cells that detect photons and convert them into electrical signals
types: rods and cones
input layer of neurons
rods
photoreceptors responsible for dim light vision
highly sensitive
one can detect a single photon of light
dispersed more around the eye
cones
photoreceptors responsible for color vision
three types: S (detects blue light), M (detects green light), and L (detects red light)
located in the fovea (center of the retina)
retinal ganglion cells (RGCs)
transmit information from the eye to the brain
allow for the establishment of receptive fields
