PHGY 209 Lecture Notes - Lecture 6: Thalamus, Presbycusis, Ganglion Cell
20 Nov 2017
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Document Summary
Starting from the end of the last lecture. Temporary blindness occur in the system because photos break the bond between the opsin and the chromophores and it takes time for the opsin to be putted back with their chromophores. From dark to light = time to saturate all the rods so they do not disturb the work of the cones. The output of the retina are the ganglion cells. There is a 10 to 1 convergence between photoreceptors and ganglion cells. Remember that there is a circuitry between the photoreceptors and the ganglion cells. This circuitry does some processing, such as computing the contrast of the image that the retina receive. The information the retina sends to the brain, is not how many photons hit it, it is the contrast, or the difference in the luminance from one part of the image to the other. Retinal ganglion cells have a center surround receptive fields.
