Figure 1. Cortical mapping of curve-biased and corner-biased patches in V4 using a 4× objective lens.

(A) The stimulus set used for initial cortical mapping consisting of bars, corners, and smooth curves. (B) Vascular map. LS: lunate sulcus; IOS: inferior occipital sulcus. The black box indicates the imaging site in each subject. (C) Two-photon fluorescence images of the two monkeys. Scale bar = 400 μm. (D) Left: subtraction map showing curve-selective activation in monkey A, derived by the average response (ΔF/F0) to all curves minus the average response to all other stimuli (corners and bars). Right: subtraction map showing corner-selective activation in monkey A. (E) The equivalent of (D) for monkey B. (F) Left: significant curve patches in monkey A. For each pixel, independent t-tests were performed to compare the responses to all curves against all corners and against all bars. Benjamini-Hochberg procedure was used to compute the pixel FDR (false discovery rate, see Materials and methods). Threshold q = 0.01. The white box indicates the imaging site selected for 16× objective single-cell mapping. Right: significant corner patches in monkey A. (G) The equivalent of (F) for monkey B.

Figure 1—figure supplement 1. Two-photon fluorescence images.

The numbers indicate the average fluorescence of the areas marked by the red boxes (normalized).

Figure 1—figure supplement 2. Pseudo-color orientation map obtained by 4× imaging.

Scale bar = 400 μm. For each pixel, the preferred orientation was derived by the vector summation of its responses (Gaussian smoothed ΔF/F0) to eight orientations. Hues in the map indicate the orientations of the sum vectors (preferred orientation), and lightness indicates the length (orientation selectivity). Orientation is organized in linear bands and pinwheels in V4.

Figure 1—figure supplement 3. Maps of uncorrected p-values (p<0.01), FDR q-values (q < 0.01), and Bonferroni-corrected p-values (p<0.01), before cluster permutation tests.