Direction preference maps calculated by vector summation were not changed with moving speed of random-dot stimuli.

<p>(A) Image of the cortical vasculature. The green and orange polygons indicate regions of areas 17 and 18 selected for analysis, respectively. A, Anterior; L, lateral. Scale bar: 1 mm. (B) Direction preference maps calculated by vector summation acquired using sine-wave grating stimuli in areas 17 and 18. Hues in the color maps indicate direction preferences. (C) Differential direction maps activated by four different pairs of directions of moving sine-wave gratings and random dots with different speeds. (D–E) Direction preference maps calculated by vector summation acquired using random-dot stimuli with different speeds in areas 17 (D) and 18 (E). Angular differences between direction preference maps of sine-wave grating and of random-dot stimuli with different speeds are shown in the histograms. Computed from the angular-difference histograms of 5°/s, 30°/s, and 60°/s,the percentages of pixels with angular difference between −60° and 60° amount to 73%, 78%, and 75% in area 17 (D) and 78%, 82%, and 80% in area 18 (E), respectively.