Reid, RC and Shapley, RM Spatial structure of cone inputs to receptive fields in primate lateral geniculate nucleus. Midget pathways of the primate retina underlie resolution and red green color opponency Copyright: Roorda and Williams made direct measurements of spectral sensitivity of foveal cones in the living human eye by a sophisticated technique of adaptive optics to increase spatial resolution. Serial section electron microscopy and reconstruction of axons and dendrites of midget ganglion cells at the edge of the central area i. Thus the grating cannot be uniquely resolved.
Viewing Golgi stained wholemount primate retinas has been particularly helpful in revealing the differences between the three ganglion cell types that are involved with spatial and color vision:
The midget pathways of the primate retina.
Midget pathways of the primate retina underlie resolution and red green color opponency Copyright: This is accomplished by making the connections as "private" as possible and narrowing them to a one to one relationship in the so-called midget pathways. However, the story may be different in the peripheral retina where the midget ganglion cells have larger dendritic fields. The optical blur of the eye minimizes Moire effects in spatial sampling Fig. The important distinction between two types of midget bipolar cell was not made until an electron microscope study was able to show differences in their synaptic contacts with the cone pedicle Kolb, The lower branching midget ganglion cell with the larger dendritic tree is probably an ON center type Why the OFF center type has a smaller dendritic tree compared with ON center type remains a mystery at present but one implication may be that the midget OFF system acuity is higher than the ON system acuity