By Jonathan Stone
In the mid-sixties, John Robson and Christina Enroth-Cugell, with out knowing what they have been doing, trigger a digital revolution within the examine of the visible procedure. They have been attempting to follow the equipment of linear structures research (which have been already getting used to explain the optics of the attention and the psychophysical functionality of the human visible procedure) to the houses of retinal ganglion cells within the cat. Their proposal was once to stimulate the retina with styles of stripes and to examine the best way that the signs from the guts and the adverse encompass of the respective box of every ganglion mobilephone (first defined through Stephen Kuffier) have interaction to generate the cell's responses. the various ganglion cells behaved themselves very properly and John and Christina bought into the behavior (they now say) of calling them I (interesting) cells. besides the fact that. to their annoyance, nearly all of neurons they recorded had nasty, nonlinear homes that could not be envisioned at the foundation of straightforward summ4tion of sunshine in the middle and the encompass. those uncoop erative ganglion cells, which Enroth-Cugell and Robson first and foremost referred to as D (dull) cells, produced temporary bursts of impulses whenever the distribution of sunshine falling at the receptive box was once replaced, no matter if the entire mild flux used to be unaltered.
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Extra resources for Parallel Processing in the Visual System: The Classification of Retinal Ganglion Cells and its Impact on the Neurobiology of Vision
1972), led to intensive study of the LGN in terms of Y, X, and (subsequently) W cells (see Chapter 6). Both Fukada (1971) and Cleland et al. (1971) included several other observations on parameters of X and Y cells; Fukada, for example, showed an "adapting" response in X cells but not Y cells, while Cleland et al. (1971) noted that McIlwain's periphery effect is strong in most Y cells, but weak or absent in X cells, and also noted the particular responsiveness of Y cells to fast-moving stimuli.
Spots of light are not natural stimuli for the frog in the way that a fly or worm is.... As the studies performed by four of the five classes are essentially independent of change in illumination, to study luminosity responses cannot contribute further insight into their natural functions and can only inform about what we would consider accidental properties of these cells. " When that true operation has been identified, meaningful quantitative questions can be asked about it, and answered. No suggestion was made, however, as to how the true operation could be reliably identified, except that natural stimuli should be tried in a nonquantitative way.
Enroth-Cugell and Robson's (1966) study, which began the development of the Y/X/W classification, was designed to extend this stream of analysis by measuring yet another parameter, the responses of individual ganglion cells to grating stimuli of threshold and suprathreshold contrast; the classification of ganglion cells into X and Y groups reported there was an unexpected observation shown only several years later to be of fundamental importance. It could be argued that most of the studies of receptive fields just characterized as parametric do not belong in an account of ganglion cell classification since, between the pioneering studies of Hartline (1938, 1940a,b) and of Enroth-Cugell and Robson's 1.