[16] This information is also useful for detecting the difference in positions of objects on the retina of each eye, an important tool in binocular depth perception.
[5][14][19] The information sent to the intraparietal sulcus (IPS) of the posterior parietal cortex allows the magnocellular pathway to direct attention and guide saccadic eye movements to follow important moving objects in the visual field.
[16] This ability has led some neuroscientists to hypothesize that the purpose of the magnocellular pathway is not to detect spatial locations, but to guide actions related to the position and motion of objects.
Recordings of S potentials at the axon terminals of RGCs in the LGN suggest that there is high contrast sensitivity in the cells terminating in the magnocellular layer of primates; opposed by low contrast sensitivity in cells found in the parvocellular layer.
[3] Both old and new world primates have been used as model systems for human vision and have subsequently been beneficial in researching parasol cells.
[8] Many retrograde labeling experiments using macaques, for example, have linked parasol and midget retinal ganglion cells with the magnocellular and parvocellular pathways respectively.
[3][8] Research by Dacey (1996) supports this idea where in vitro primate retinal cells were treated with dye fillings.
[3] In other studies, new world monkeys, such as marmosets, have aided in the current understanding of spatial and temporal frequency of the magnocellular layer in the LGN.
[11] Retinal ganglion cells of cats have been studied and compared to those in the visual system of both primates and humans.
Additionally, autoimmune attacks by antineuronal antibodies may prevent adequate parasol ganglion cell development for normal functioning, a theory which would explain why weakened immune systems are frequently present in dyslexic individuals.