TABLE 3.
Species
|
||||
---|---|---|---|---|
Macaque | Cat | |||
Reference2 | 1 | 2 | 3, 4 | 3 |
Type | DB3 | Cb2 | CBa1* | CBa4 |
Cone synapses | Mostly basal | Basal | ? | ? |
Axon stratification | Narrow | Narrow | Narrow | Narrow |
Axon depth in IPL | s.l. a | s.l. a | s.l. a | s.l. a |
Postsynaptic GC types | Parasol | α, β | α, β | ? |
Input from AII ACs | Yes | Yes | Yes | Few |
Output to AII ACs | Yes | Yes | Yes | Yes |
Gap junctions with other BCs | Yes | Yes | ? | ? |
Output to ACs (%) | 61 | 48 | 50 | 60 |
Postsynaptic ACs that feed back (%) | 47 | 17 | 5 | 56 |
Feedback as percent of total input (%) | 25 | 12 | 7 | 59 |
Comparisons between macaque DB3 bipolar cells and cat bipolar cells with similar morphology. One of the two CBa1 cells of McGuire et al. (1984) had narrowly stratified axons in the IPL; only its synapses are shown here. The percentage data from Kolb (1979) were obtained by counting synapses made by the smooth, flat cone bipolar axon reconstructed in her Fig. 16. The percentage of output to amacrine cells reflects the proportion of postsynaptic elements that are amacrine cells. The percentage of postsynaptic amacrine cells that give feedback is the proportion of postsynaptic amacrine cells that make synapses onto the same bipolar cells that provide their inputs. The feedback as a percentage of total input is the proportion of amacrine cell synapses onto the bipolar cells that are feedback synapses.
1, Boycott and Wässle, 1991; Hopkins and Boycott, 1997. 2, Kolb, 1979; Kolb et al., 1981. 3, McGuire et al., 1984 (*cell 14). 4, Pourcho and Goebel, 1987. DB, diffuse bipolar; Cb, cone bipolar; IPL, inner plexiform layer; s.l., sublamina; GC, ganglion cell; AC, amacrine cell; BC, bipolar cell.