Fig. 2. Example of data analysis for a V1 neuron. (A) Response to a full-field grating. (B) Vector map showing directional preference within the receptive field. (C) Response to individual patches at circled positions in B. (D) Response to two simultaneous patches. The direction of patch 1 is on the x axis, that of patch 2 on the y axis. (E,F) Computed as shown in Fig. 1B, responses to the patch at position 1 when preceded by the patch at position 1 (E) or 2 (F). (H–K) (H,I) were obtained from E and F after subtracting the average column, (J,K) after further subtracting the average row (see Materials and methods). (G) Slices across H along the positions indicated by coloured lines in H (black in G corresponds to the white rectangle in H). Arrows in G point to the direction of the y axis in H along which the slice was taken. Intensity in D–F,H,I shows firing rate plotted to the same scale where white is 88 Hz and black is –24 Hz (with respect to spontaneous firing of 43 Hz, indicated by dotted line in A). J and K plot Z scores (coloured for |Z|>2, blue for negative and red for positive). Smooth contours show interpolated surfaces with colour saturation and line thickness reflecting modulation intensity. Values are means ±1 s.e.m.; for N values, see Materials and methods.