Giant bistratified bipolar cells in monkey retina



A bipolar cell type with a dendritic span in the outer plexiform layer (OPL) larger than any other type of monkey retinal bipolar cell and an axon which terminates in two separate strata (Polyak's 7a and 7d) of the inner plexiform layer (IPL) are described from Golgi-impregnations of the rhesus monkey retina. These giant bistratified bipolar cells connect with many cones in the OPL, and although the axon has terminals in both the outer and inner parts of the IPL, Golgi-electron microscopy (EM) demonstrates that the nature of this cell type's dendritic contacts with cones is as wide-cleft basal junctions.