Morphologies of rabbit retinal ganglion cells with complex receptive fields

Abstract

Ganglion cells that had complex receptive field properties, namely, On-Off and On direction-selective cells, orientation-selective cells, local edge detectors, and uniformity detectors (suppressed by contrast cells) were recorded in an isolated superfused rabbit eyecup preparation. Cells were first classified by their characteristic extracellular responses to manually controlled stimuli similar to those which have been used in previous in vivo studies. Ganglion cells were then impaled, confirmed in identity by intracellular recording, and iontophoretically injected with horseradish peroxidase for staining. Twenty-two ganglion cells, which included members of all the major classes mentioned above, were recovered from the visual streak or near periphery. All recovered cells were drawn in camera lucida from flat-mounted retinas and entered into a computer as two-dimensional stick figures; nearly all were three-dimensionally reconstructed to determine the level and manner of dendritic ramification in the inner plexiform layer (IPL). The location of ganglion cell dendrites in sublaminar regions of the IPL was found to be consistent with the hypothesis of a division of the IPL into excitatory On (proximal) and Off (distal) sublaminae, with some qualifications for particular classes. Each of the complex receptive field ganglion cell classes exhibited a distinctive three-dimensional dendritic arborization pattern uniquely associated with that physiological class.