Variability in responses of retinal ganglion cells

Changes in the maintained discharge of retinal ganglion cells have been modeled by addition of noise to a rate-setting signal, whereas the responses of cortical cells have been reported to indicate a nonlinear relationship between noise and signal. To determine whether this represents a difference between retinal cells and cortical cells, the variance of light-evoked responses of ganglion cells in the retinas of goldfish was compared with the magnitude of the responses. Variance increased for higher firing rates. These results are discussed in terms of mechanisms by which light-evoked signals might interact with the variability of maintained discharges.