Cells of origin of the frontal projections to magnocellular and parvocellular red nucleus and superior colliculus in cynomolgus monkey. An HRP study.

Cells of origin of frontal cortical projections to parvocellular and magnocellular red nucleus (MRN) and superior colliculus were identified by means of retrograde HRP transport. The cells projecting to parvocellular red nucleus (PRN) are mainly located in areas 6 and 4, and are situated in the upper part of layer V, i.e. above the Betz cells, while those projecting to MRN are mainly located posteriorly in area 4, and are situated deep in layer V, i.e. at the level of the Betz cells. The neurons projecting to superior colliculus are located deep in layer V of areas 9, 8 and 6.