BPK 306 Lecture Notes - Lecture 28: Trichromacy, White Spot, Retina Horizontal Cell
5 Dec 2017
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Like rhodopsin in rods (for peripheral, black and white, and low light vision) Opsins in cones initiate sensory transduction, except there are multiple opsins sensitive to different wavelengths. Differences in spectral sensitivity of cone opsins are due to differences in amino acid sequence. At the bipolar (and ganglion) cell level: cells get excited best by one colour opsin, and inhibited by others, this is called opponent process because 2 colours are fighting against each other. 2: opponent process involves lateral inhibition and interneurons (horizontal cells, white spot = neither red or green, retinal ganglion cells express opponent process receptive fields, ex. red vs. green, center-surround receptive fields are mediated by interneurons. 3: on-center/off-surround with light shone onto the center. If light shone onto surround then -> lateral inhibition = less gc firing. Can also have center-surround cells respond to different colours: ex.
