Cortical inputs to the CA1 field of the monkey hippocampus originate from the perirhinal and parahippocampal cortex but not from area TE.

We determined the cortical regions that project directly to the CA1 field of the monkey hippocampus by injecting the retrograde tracers Fast blue, Diamidino yellow or WGA-HRP into CA1 and examining the distribution of labeled cells. In the temporal lobe, large numbers of retrogradely labeled cells were observed in the perirhinal and parahippocampal cortices. Only an occasional labeled cell, however, was observed in the unimodal visual area TE. Additional projections to CA1 arose in the dorsal bank of the superior temporal sulcus, in the rostral and retrosplenial portions of the cingulate cortex, in the agranular insular cortex, and in the caudal orbitofrontal cortex.