The other two pathways are the parvocellular and koniocellular
Midget cells form the start of the parvocellular system, which processes 'red-green' cone opponent information, whereas the bi-stratified ganglion cells, which form the koniocellular
system, process 'blue-yellow' colour signals.
The retinogeniculostriate visual system consists of three major tracts: the dorsal, ventral, and koniocellular
pathways that conduct electric messages from the retina to the occipital cortex.
In normal non-athletes, BYOC contrast sensitivity is mediated by the koniocellular
pathway that tends to exhibit a low pass curve  while band pass (better contrast sensitivity for middle SFs) is seen when testing with monochromatic gratings.
Effects of retinal ganglion cell loss on magno-, parvo-, koniocellular
pathways in the lateral geniculate nucleus and visual cortex in glaucoma.
The S cone signal is, therefore, differenced with the sum of L and M signal to form the Koniocellular
(K), or blue/yellow pathway, and contributes a small amount to the luminance channel.
The background reduces the sensitivity of the green and red cones, therefore the blue (short-wavelength sensitive) cones and their small, bistratified retinal ganglion cells are isolated (the koniocellular
People with AD may experience loss of blue/violet sensitivity, which may be associated with damage to the koniocellular
cells within the LGN receive their input from bistratified retinal ganglion cells exiting the optic tract, and send their information via the optic radiation to the primary visual cortex.
The signal from the S/(L+M) system passes through the koniocellular
levels of the lateral geniculate nucleus (LGN) (43) and then to the cytochrome oxidase blobs in layers 2 and 3 of the striate cortex.
There is also a third pathway, the koniocellular
pathway, which is comparatively little studied but may turn out to be of considerable importance.