Axons in Po labeled by BDA injections in glutamatergic subcortical structures. Microphotographs showing location of BDA deposits in the cuneatus (Cu; a) and gracilis (Gr; c) nuclei, ventrolateral part of principal trigeminal nucleus (PrV-VL; e), or pars caudalis of the spinal trigeminal nucleus (SpVC; g). Cytochrome oxidase counterstain. Confocal images of double immunofluorescence labeling within the contralateral Po of vGLUT2 terminals (green) and BDA axons (magenta) from Cu (b), Gr (d), PrV-VL (f), and SpVC (h). Insets are represented as white squares. High-magnification detail is shown for each case. Arrowhead indicates BDA axonal varicosities immunopositive for vGLUT2. AP: bregma level in mm. Scale bars: 250 µm (a, c, e, g), 100 µm (b, d, f, h), and 25 µm (b1, d1, f1, h1). Similar images from BDA injection cases involving the dorsomedial region of principal trigeminal nucleus, the oralis or interpolaris parts of the spinal trigeminal nucleus, the parabrachial nuclei, the superior colliculus, or the cervical spinal cord are provided as Extended Figure 13-1.