Retina bipolar cell Retina bipolar cell As a part of the retina, bipolar cells exist between photoreceptors (rod cells and cone cells) and ganglion cells. They act, directly or indirectly, to transmit signals from the photoreceptors to the ganglion cells. Bipolar cells are so-named as they have a central body from which two sets of processes arise. They can synapse with either rods or cones (rod/cone mixed input BCs have been found in teleost fish but not mammals), and they also accept synapses from horizontal cells. The bipolar cells then transmit the signals from the photoreceptors or the horizontal cells, and pass it
George Wald methods to extract pigments from the retina. Then, using a spectrophotometer, they were able to measure the light absorbance of the pigments. Since the absorbance of light by retina pigments corresponds to the wavelengths that best activate photoreceptor cells, this experiment showed the wavelengths that the eye could best detect. However, since rod cells make up most of the retina, what Wald and his colleagues were specifically measuring was the absorbance of rhodopsin, the main photopigment in rods. Later, with a technique called microspectrophotometry, he was able to measure the absorbance directly from cells, rather than from an extract of