Axonal varicosities in Po labeled by BDA injections in glutamatergic subcortical input structures. Schematic representation of the location of axonal varicosities in Po and adjacent thalamic nuclei, plotted from the anterograde axonal labeling of BDA microiontophoretic injection sites in gracilis nucleus (a), cuneatus nucleus (b), ventrolateral region of principal trigeminal nucleus (PrV-VL; c), the caudalis part of the spinal trigeminal nucleus (SpVC; d), superior colliculus (SC; e), and cervical spinal cord (f). Individual axonal varicosities in Po are represented as red circles, and axonal varicosities outside Po are represented in gray color. Ang: angular thalamic nucleus; LD: laterodorsal nucleus; LP: lateral posterior nucleus; LPM: lateral posterior nucleus, medial part; LPL: lateral posterior nucleus, lateral part; PC: paracentral nucleus; PF: parafascicular nucleus; VL: ventrolateral nucleus; VPM: ventral posteromedial nucleus. AP: bregma level in mm. Scale bar: 250 µm. Additional diagrams in Extended Figure 14-1 illustrate the location of varicosities labeled in Po by BDA deposits in the dorsomedial region of principal trigeminal nucleus, the oralis or interpolaris parts of the spinal trigeminal nucleus or the parabrachial nuclei.