FIGURE 2

FIGURE 2

First studies describing orientation-selective ganglion cells in vertebrate retinae. (A) Discovery of horizontally tuned OSGCs in the pigeon retina by Maturana and Frenk (1963). In A (right side), the firing of a pigeon OSGC in response to a horizontal bar moving downward (D) or upward (U) is represented. As shown in B, C and D, the same cell does not respond to a vertically oriented bar moving leftward or rightward (B), nor to a horizontal bar presented over the receptive field surround (C), or to a small spot moving over the receptive field center (D). Image taken from Maturana and Frenk (1963) with permission. (B) Characterization of OSGCs in the rabbit retina by Levick (1967). Spiking responses of an OSGC to light or dark bars with different orientations moving across the receptive field center. The mapping of the receptive field center is also represented at the center of the schematic. The ‘+’ symbol indicates responses to a stationary spot at light ON; ‘–’, at light OFF; ‘ ± ’, at both light ON and OFF; ‘o’, no response detected. The traces show the spiking responses elicited by the bars (upper trace; number of spikes is reported after each response) and the output of a photomultiplier focused on the receptive field (lower trace; an upward deflection indicates light increase). Note that only horizontally oriented bars elicited responses. A, Anterior; S, superior. Image taken from Levick (1967) with permission.