The projection from the lateral geniculate nucleus to the prestriate cortex of the macaque monkey

By injecting the enzyme horseradish peroxidase into the prestriate cortex of the macaque monkey and examining the lateral geniculate nucleus (l. g. n.) for retrograde label, the presence of a direct projection from the l. g. n. to prestriate visual cortex (Brodmann’s areas 18 and 19) was confirmed. Labelled cells occurred in all layers of the l. g. n., distributed in a roughly columnar fashion. The large scatter in cell distribution indicated a lower retinotopic precision for this projection than for the one to area 17. Labelled cells are of a medium to large size and, in each section, a few were located near the laminar border or in interlaminar zones. The functional significance of this projection is discussed.