Retinotopic scatter of optic tract fibres in the cat.

The retinal fibers in the optic tract (OT) of the cat have a roughly retinotopic arrangement. The retinotopic scatter of OT fibres at the rostral pole of the superior colliculus (SC) and at the lateral margin of the lateral geniculate nucleus (LGN) was investigated using the retrograde transport of horseradish peroxidase. Small lesions and injections were made in the tract and from the distribution of labelled ganglion cells in the retina the retinotopic precision was measured. At an eccentricity of 30 degrees along the horizontal meridian the vertical scatter was 20-30 degrees. This is similar to the precision of the map in the SC. However a comparison with the retinotopic map of the LGN shows the precision there to be much better.