Horizontal projections of area 17 in Cebus monkeys: metric features, and modular and laminar distribution

ABSTRACT

Metric features and modular and laminar distribution of intrinsic projections of area 17 were studied in Cebus apella. Anterogradely and retrogradely labeled cell appendages were obtained using both saturated pellets and iontophoretic injections of biocytin into the operculum. Laminar and modular distributions of the labeled processes were analyzed using Nissl counterstaining, and/or cytochrome oxidase and/or NADPH-diaphorase histochemistry. We distinguished three labeled cell types pyramidal, star pyramidal and stellate cells located in supragranular cortical layers (principally in layers IIIa, IIIb alpha, IIIb beta and IIIc). Three distinct axon terminal morphologies were found i.e., Ia, Ib and II located in granular and supragranular layers. Both complete and partial segregation of group I axon terminals relative to the limits of the blobs of V 1 were found. The results are compatible with recente evidence of incomplete segreagation of visual information flow in V 1 of Old and New World primates.