Figure 1

Anterograde labeling in the olfactory tubercle following tracer injections into the dentate gyrus. Photomicrographs taken by transmitted and polarized light showing anterograde projections to the olfactory tubercle (D, E, F, H, I, J; arrows point to labeling) and/or the anterior hippocampal continuation (D, G) following tracer injections into the dentate gyrus in Et01-21B (A, D), Et98-49W (B, E, F), Et01-36B (C, G) and Et00-11B (H – J). The molecular layer of Tu was labeled in all cases (D-H, ipsilateral side; I and J, contralateral side) but Et01-36B (G) where the tracer injection scarcely involved the DtHi (note the low labeling density of the mossy fiber projection to CA3 in C [arrow head] as compared to A). The Acb (D, E) was not labeled following tracer injections into Dt unlike the cases injected with tracer into CA1 / Sbi. All BDA cases also clearly labeled the HCt (D, G) due to the retrograde-anterograde collateral transport of the tracer within the entorhino-hippocampal system described previously [28]. Open arrow heads in E, F and I, J respectively point to similar location. Scale bars in B (also applying to A and C) and G (also applying to D) 0.5 mm; in E and J = 0.4 mm, in H = 0.3 mm; in F and I = 0.2 mm.