Eeek! I'm a divergent fuser.
Here is a super-realistic rendition of complex cell binocular RF!
Binocular Receptive Field of Complex Cells
The first stage of information processing for stereoscopic depth perception is thought to be the primary visual cortex, where information from the two eyes is thoroughly combined. For these neurons, there are receptive fields for each eye. The conjunction of these fields defines a binocular receptive field in the three-dimensional visual space (X, Y, Z), where Z is the distance from the viewer. The figure above depicts a binocular receptive field for a type of neuron (complex cell) in the cat's primary visual cortex, rendered as a stereogram. The horizontal axis in the center of the cube (Z axis) indicates the viewing direction of the subject. The subject's location is in the lower right and it is fixating the center of the cube. The green disk-shaped contour indicates the region of 3-D space where a target of appropriate orientation excites the neuron. The two regions shown in red depict the suppresive regions in which a target causes a reduction of response. Note that the neuron is much more sensitive to position change along the depth dimension (Z axis) than to translations along the plane of the central disk (X-Y plane).
You might notice that the (X, Y, Z) receptive field shown above lacks a description of the time dimension, which we have emphasized that we must consider. For complex cells in the striate cortex, there is not much additional information gained from the time dimension. The (X, Y, Z) and the T dimensions are separable. If we were to show the time dimension by animation of the above stereogram, you will simply see the appearance of the (X, Y, Z) RF which then disappears over a period of about 300 msec (with a peak occuring typically at 60-80 msec). The shape of the (X, Y, Z) RF does not change over the time course of the response for all complex we have examined (N=44). We also do not see any inversion of the phase unlike typical simple cell's space-time RFs. That is, the time dimension of the binocular RF is monophasic for all complex cells we have recorded.
See our paper Ohzawa et al. J. Neurophysiol. 77: 2879-2909 1997 (Figs. 10, 11 and 15), for details.
3-D visualization software NXplotNd courtesy of Dr.
Steve Ludtke, http://alumni.caltech.edu/~stevel/.
Images are rendered using Pixar's PhotoRealistic RenderMan from RIB files generated by NXplotNd.
Copyright 1997, Izumi Ohzawa, All rights reserved.