Still with Us after All These Years: Issues of Neuronal Classification Revisited

stages of the pathway, the retina and lateral geniculate nucleus, had the centersurround organization previously described by Kuffler [1953]. Soon, however, descriptions of retinal receptive fields lacking center-surround organization began to appear [Stone and Fabian, 1966; Rodieck, 1967]. Even among ganglion cells that did have center-surround receptive fields, fundamental differences in other response properties were observed [Enroth-Cugell and Robson, 1966], and it was not long before the full extent of the diversity among the ganglion cell population was well documented [Stone and Hoffmann, 1972; Cleland and Levick, 1974a, b; Stone and Fukuda, 1974; Hochstein and Shapley, 1976]. During this same period, additional evidence from Canberra [Cleland et al., 1971; Hoffmann and Stone, 1971; Wilson et al., 1976] suggested that this retinal diversity might underlie some of the diversity observed in cortical receptive fields. If that were the case, it would have required significant revision of the hierarchical scheme proposed by Hubel and Wiesel [1962], and although all of this initial work was done in cats, it quickly became apparent that primate retina and visual pathways were organized in very similar ways [Dreher et al., 1976; De Monasterio, 1978]. So any revision of the This paper was written in 1976, shortly after Jonathan Stone had relocated his lab from the Australian National University (ANU) in Canberra to the University of New South Wales in Sydney. I had joined Jonathan’s lab as a post-doc early in 1975, when he was still in Canberra. At that time, the Physiology Department at ANU was headed by Peter Bishop and included a number of other prominent researchers (Geoff Henry, Bill Levick, Brian Cleland, Austin Hughes), and an ever changing contingent of visiting scholars, post-docs and grad students, all working in vision. So, I had been looking forward to entering an environment filled with lively discussions of the latest ideas and results. Indeed, upon my arrival I found myself in the middle of a spirited competition between Jon’s lab and another group in the department led by Bill Levick that involved competing narratives for the still emerging story of retinal ganglion cell diversity and parallel retino-geniculo-cortical pathways. At the time, there was very widespread interest in these issues because of their implications for models of cortical organization. When Hubel and Wiesel [1962] proposed that simple and complex cells in the visual cortex represented successive stages in a signal processing hierarchy, they assumed that all receptive fields at lower Published online: June 28, 2012