Fig. 2.

(A) Plot of the vector length sensitivity of cells from data by Croner and Kaplan (1995). Each data point in the vector length plot (dots) represents a cell whose receptive field is modeled with the DoG parameters reported by Croner and Kaplan (1995). Vector length sensitivity (unitless) is monotonically increasing proportional to frequency. The x-coordinate of the vector length plot is in units of log mean spatial frequency (cyc/deg) for each cell (see text for definition). (B) Plot of the response magnitude for ganglion cells to a distribution with a spatial frequency power spectrum that falls as 1/f². This 1/f² “input” represents a typical natural scene. Sensitivity is given by vector length (A). Responses show a generally flat shape across spatial frequency. Dotted line in (A) represents a slope of 1 on the log-log plot.