Morphological correlates of physiologically identified Y-, X-, and W-cells in cat retina

J Neurophysiol. 1984 Dec;52(6):999-1013. doi: 10.1152/jn.1984.52.6.999.

Abstract

The action spike activities of single ganglion cells were recorded from the nasal retina of the intact eye of anesthetized and immobilized cats. Each ganglion cell was identified as a Y-, X-, or W-cell on the basis of its axonal conduction velocity, its receptive-field properties, and the level of maintained activity. Of about 100 ganglion cells physiologically identified and penetrated with horseradish peroxidase (HRP)-containing glass microelectrodes, 21 cells were subsequently identified in flat-mount preparations of the retinas and processed for detection of HRP. Of a total of nine Y-cells recovered, four had been penetrated at the soma and five at the axon. All had the morphology of the alpha-cell of Boycott and Wässle. Eight X-cells recovered. All had been penetrated at the soma and showed beta-cell morphology. Four W-cells were penetrated at the soma and recovered. Two off-tonic W-cells had small somas (15-16 micron in diam) and sparse dendritic fields, resembling gamma-cells of Boycott and Wässle. They are also similar to "G4" and "G18" of Kolb et al.'s classification. One on-tonic W-cell had somewhat larger soma (18 micron) with a relatively densely branched dendritic field. This corresponds to delta-cell of Boycott and Wässle or to "G15" of Kolb et al. One on-off phasic W-cell had a medium-sized soma (25.3 micron) with a fanlike dendritic expansion characteristic of the "unilateral horizontal broad range cell" of Shkolnik-Yarros or of "G22" of Kolb et al. Alternatively, all these W-cells can be called medium-sized gamma-cells. Among all three classes of ganglion cells, a positive correlation was found between the diameter of the receptive-field center and the dendritic field. Assuming that in the cat retina 1 degree of visual angle = 230 micron, dendritic fields of Y-cells seemed larger than their physiologically determined receptive-field centers. By contrast, the reverse relation was found between these two dimensions in X-cells. Axon diameters ranged from 4.0 to 5.6 micron (mean, 4.5 micron) in Y-cells and from 1.9 to 2.7 micron (mean, 2.2 micron) in X-cells. Three W-cells showed axon diameters of 0.6, 1.1, and 1.8 micron. The axon diameter distributions made from axons labeled by massive injections of HRP into the optic nerve fiber layer showed a pattern of distribution similar to that obtained from physiologically identified Y-, X-, and W-cell axons.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / physiology
  • Axons / ultrastructure
  • Cats
  • Dendrites / ultrastructure
  • Evoked Potentials, Visual
  • Neural Conduction
  • Photic Stimulation
  • Reaction Time / physiology
  • Retina / ultrastructure*
  • Retinal Ganglion Cells / classification
  • Retinal Ganglion Cells / physiology
  • Retinal Ganglion Cells / ultrastructure*