The layout of these maps are quite similar to that of Figure 4. However now the activity of one cell in the middle layer is plotted as a function of the location and speed of a motion stimulus in the input layer. One could imagine that an electrode was placed in one of the cells of the middle layer while the experimentalist moved a bar about along the horizontal meridian with different locations and speeds. The activity of the cell is then plotted as a function of position and space. The activity of two different cells in the middle layer.
Activity is plotted as a contour map as a function of horizontal position and speed.
These middle layer receptive field maps were interesting because they appear to be quite simple and symmetrical. Complementary cells were also found. The above results suggest that neurons involved in extracting structure from motion may have relatively simple receptive fields in the spatial velocity domain. These receptive fields might be thought of as breaking the image down into component parts. Correct recombination of these second order cells could then be used to detect the presence of a three-dimensional structure.