(A) A schematic representation of the macaque brain showing the imaging region (green circle) and sulci locations. lu, lunate sulcus; st, superior temporal sulcus; and io, inferior occipital sulcus. (B) In vivo image of the blood vessel pattern in the 16 mm diameter imaging region in Case 1, which included parts of V1, V2, and V4. The exposed V4 region was between the st and lu sulci. A, anterior; M, medial. (C) An illustration of the full-screen stimulus pattern used for ISOI imaging. Circle diameter: 2.5°. Drifting speed: 4°/s. (D–L) Functional maps (SVM maps) from Case 1. The icons shown at the top represent the stimulus conditions being compared. In the ISOI maps, dark and white regions were preferentially activated by the stimulus icons shown on the left and right, respectively. For the maps shown in G, H, J, and K, data from different stimulus orientations were pooled for lines, curves, and angles. Other maps were obtained with the exact stimuli as shown on the maps. (D) The circle vs. triangle map shows clear patches in V4 (dark regions preferred circles and white regions preferred triangles), which were absent in V1 and V2. The dotted line represents the border between V1 and V2. (E) The orientation preference map shows the 45° (dark) and 135° (white) orientation domains in V2 and V4. The lack of orientation domains in V1 could have been resulted from the low SF of the stimulus gratings (0.25 c/degrees). (F) The color preference map shows the color domains in V1, V2, and V4. (G) The circle vs. straight line map shows a preference pattern similar to that in the circle vs. triangle map (D). (H) The curve vs. straight line map shows patterns similar to those in D and G. The curve was a half-circle. (I) The curve-orientation map shows smaller and weaker patches preferring different curve orientations. (J) The triangle vs. straight line map shows weaker and larger patches than those in the circle vs. straight line map in G. The dark domains preferred triangles over lines and occupied the same regions as the white patches in D. (K) The angle vs. straight line map shows a very weak pattern similar to that in J. (L) There was no clear pattern in the angle-orientation map.