Figure 1.

Optical imaging and analysis of orientation preference maps in the ferret visual cortex. (A) Image of the exposed region of the visual cortex in ferret 22 (see Fig. 2), showing typical appearance of the cortical surface (dotted line indicates the region analyzed in B and C). (B) Orientation preference map of the cortical regions responding best to different stimulus orientations (bar shows the orientation color code; bar length = 3 mm). (C) Histogram of the region of interest (see dotted line in A), showing the number of pixels (i.e., the area of cortex) that responded best to each orientation. Note the peaks near the vertical and horizontal meridians, which indicate that more cortex responded best to contours in the cardinal axes compared with those at oblique angles.