(A) Series of adjacent 100-μm–thick coronal sections of an E18.5 mouse brain used as a model for BDA axon tracing and injection site reconstruction. Sections numbered from 1 to 34 (rostral to caudal) were counterstained with DRAQ5, revealing the cytoarchitecture of distinct regions outlined in (B). (B) Segmentation of distinct regions used for reconstructions as shown in Figure 1. Red indicates cortex; yellow, corticostriatal boundary; green, DTh; blue, ganglionic eminence (VTel); and pink, hippocampus. (2.41 MB TIF)