Receptoral and Neural Aliasing.

This project saw some unexpected successes, and some even more unexpected failures. Chief among the latter was our total failure to replicate Williams observations of receptoral aliasing, either in the fovea or the parafovea. Despite much communication between us and Williams, no explanation of this discrepancy has been found. We present substantial evidence below to eliminate the possibility of technical failure in our experiments. Unable to study aliasing directly, we pursued a very different approach to the problems of retinal geometry and aliasing we studied methods to directly map the parafoveal visual field into its constituent summation areas presumably receptive fields. Although we have not fully solved the very difficult problem of eye-movements, several successful studies were performed, notably 1 the development of a precise new method for measuring fixation accuracy using afterimages, and 2 studies of spatial summation for isoluminant spots in the parafovea. In addition, a computer model was designed that produces sample ganglion cell lattices and models the process of chromatic identification. Finally, we diverged considerably from the original focus of the project to design what we believe to be the most powerful stimulus display for visula research currently available. This is now a commercial product, showing both scientific and financial success.