In the mid-sixties, John Robson and Christina Enroth-Cugell, without
realizing what they were doing, set off a virtual revolution in the
study of the visual system. They were trying to apply the methods of
linear systems analysis (which were already being used to describe the
optics of the eye and the psychophysical performance of the human visual
system) to the properties of retinal ganglion cells in the cat. Their
idea was to stimulate the retina with patterns of stripes and to look at
the way that the signals from the center and the antagonistic surround
of the respective field of each ganglion cell (first described by
Stephen Kuffier) interact to generate the cell's responses. Many of the
ganglion cells behaved themselves very nicely and John and Christina got
into the habit (they now say) of calling them I (interesting) cells.
However. to their annoyance, the majority of neurons they recorded had
nasty, nonlinear properties that couldn't be predicted on the basis of
simple summ4tion of light within the center and the surround. These
uncoop- erative ganglion cells, which Enroth-Cugell and Robson at first
called D (dull) cells, produced transient bursts of impulses every time
the distribution of light falling on the receptive field was changed,
even if the total light flux was unaltered.