Ron If you're asking about Barlow and Hill, they recorded from the retinal ganglion cell in a rabbit's eye. They showed the rabbit a rotating disk with randomly placed spots on it. The portion of the disk that was in the receptive field of that ganglion cell would be moving in a particular direction and they could determine the preferred direction that that cell. When they displayed the disk they found that the rate of responding initially went way up but declined over the course of the one-minute exposure. When the motion was stopped the firing rate immediately fell to zero and only very gradually returned to baseline. The next step was to present the opposite direction of motion to the same cell and this produced no effect: the firing rate stayed at baseline throughout stimulation and neither declined nor rose after the firing stopped. From this they figured that the ganglion cell was paired with a cell that had an opposite preference and their firing rates were compared in order to produce the motion aftereffect. This model could account for actual motion --the ratio of one cell to the other would be high; for stability--the ration of one to the other would be equal; and of the MAE. Paul Schulman Dept of Psychology SUNY Institute of Technology Utica NY 13504
