Figure 2.

Responses of three example color-selective neurons recorded in the AITC. A, Responses of a neuron (Cell 1) to 15 stimuli in the bright set (left) and 15 stimuli in the dark set (middle). The response to each color is shown by rasters and PSTHs. The stimulus presentation period is indicated by a thick horizontal line below each histogram. The number at the bottom left of each histogram indicates the color ID that corresponds to the number of each color in Fig. 1B. Inset, The response magnitude to each color stimulus is represented by the diameter of a circle and is plotted at the position that corresponds to the chromaticity coordinate of that color (bubble plot). Open and solid circles indicate response increases and decreases, respectively. Contour lines in the bubble plots indicate 75%, 50%, 25%, and 0% of the maximum response, respectively. In the right panel, the scatter plot shows the relationship between the responses to the bright set (horizontal axis) and to the dark set (vertical axis). Each circle corresponds to one color. The correlation coefficient and the p-value between responses to the bright and dark sets are shown at the upper left of the plot. B, C, Responses of two other example neurons (B, Cell 2; C, Cell 3) to the bright and dark sets, and the relationship between the responses to the two sets (scatter plots). B, Bright set; D, dark set. Sparseness indices for the bright and dark sets were, respectively, 0.83 and 0.82 for Cell 1; 0.47 and 0.36 for Cell 2; and 0.63 and 0.67 for Cell 3.