A–C: Fiber and terminal labeling in the contralateral OS following injections of BDA into medial NA, lateral NA, and mid-NL, respectively. D: Brown (CTB) labeling in LLV and LLDp and black (BDA) labeling in LLDa, following injections of CTB and BDA in the contralateral NA and NL of the same case, respectively. Black label was produced with heavy metal (CoCl2) intensification of the DAB reaction product, while brown label was produced without such intensification (see Materials and Methods in Krützfeldt et al., 2010). Scale bars = 200 μm for A–C; 125 μm for D.