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 LGN itself maintains the separation of magnocellular, parvocellular and koniocellular signals while also keeping contralateral and ipsilateral fibres in separate layers.
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.
Slow intrinsic rhythm in the koniocellular visual pathway.
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.