Expanded photomicrographs of terminal fields in the NST, validation of P2X2 ⁺ as a proxy for CT and GSP labels, animal, and gustatory structural indices, and dLGN measurements. (A and B) Horizontal sections in the four dorsal–ventral zones of the IX (green), CT (red), GSP (blue), and the merged image (MERGE) terminal fields in representative sections of P15 and adult control mice and in adult control and adult E3–E12 diet mice (A) and in representative sections adult control and adult E3–E12 diet mice (B). Refer to the color guide in the lower portion of A for overlap color shown in the merged images in A and B. Scale bars = 200 µm. R, rostral; L, lateral. The photomicrographs for the dorsal zones in Fig. S1, A and B are duplicated from Fig. 1, C and H, respectively. (C) Myelin-stained images of horizontal sections in an adult control mouse through the four dorsal–ventral zones of the NST. The NST is outlined in black, and arrows point to the solitary tract. 4V, fourth ventricle; Sp5, spinal trigeminal nucleus, DCN, dorsal cochlear nucleus; VCN, ventral cochlear nucleus; icp, inferior cerebellar peduncle; 12, hypoglossal nucleus. Scale bar = 1 mm. (D) Coronal sections of the brainstem showing terminal fields of the IX, CT, GSP, and the merged image in a P15 and adult control and adult E3–E12 diet mice. The lowest panel shows a low-power transmitted image of the right hemifield of the brainstem in a coronal section that contains terminal field labels in an adult control mouse. 4V, fourth ventricle; MVe, medial vestibular nucleus; SpVe, spinal vestibular nucleus; Sp5I, spinal trigeminal nucleus, interpolar; Sp5, spinal trigeminal nucleus; ICP, inferior cerebellar peduncle; AMB, nucleus ambiguous; and py, pyramidal tract. The NST is outlined by the dark lines, with the subdivisions labeled as M, medial; RC, rostral central; L, lateral; and V, ventral. Scale bar = 500 µm. Three animals/group were examined for gustatory terminal fields in coronal sections. (E) Photomicrographs of GSP and CT terminal fields and P2X2⁺ labeling in an adult control mouse. The MERGE image shows all fields together. Scale bar = 200 µm and the color wheel in the panel of the CT shows the overlapping colors. (F) The percent of overlap the P2X2⁺ labeled field has with the GSP and/or the CT terminal fields from the most dorsal to ventral consecutive sections in which there is CT or GSP terminal field labels. The vertical lines denote the range of sections used for calculating the volumes of the P2X2⁺ label as the proxy. Seven adult control mice were used to examine the overlaps of terminal fields with P2X2⁺ labeling. (G) Photomicrographs of the horizontal section containing P2X2⁺ labels in a P1 control and E3–E12 mouse. The white outline denotes the borders of the NST. The orientation is as shown in A and B. Scale bar = 50 µm. (H) Mean (± SEM) body weight of male and female controls and E3–E12 diet mice for the first 30 d postnatal. n for P5, P10, P15, P20, P25, and P30 controls and E3–E12 diet mice are 9, 10; 20, 16; 20, 20; 20, 16; 19, 16; and 17, 15, respectively. (I) Number of ganglion cells in the geniculate ganglion when the CT (n = 15, controls; n = 7, E3–E12 diet) or GSP (n = 8, controls; n = 7, E3–E12 diet) was labeled, or in the petrosal ganglion when the IX (n = 6, controls; n = 9, E3–E12 diet) was labeled. (J) The volume of the right hemifield of the NST in P20 controls (n = 5) and P20 E3–E12 (n = 5) mice. (K) Left: Quantification of R-distributions (R = log₁₀ [inputs from ipsilateral/inputs from contralateral eye]; Torborg and Feller, 2004) in controls (top left) and E3–E12 diet mice (bottom left). The right two panels show the variance distributions of the R values for controls (top right) and E3–E12 diet mice (bottom right). (L) Heatmaps of putative CT synapses in the rostral NST in adult controls (left) and E3–E12 diet mice (right). The densities within each of the 10 × 10 grids (21.5 × 21.5 μm) represent the average density of CT labels in close apposition to PSD95 labels within each group. The density for each grid is normalized to the grid with the highest density found across all animals. The grid with the highest density is shown as red and occurs in approximately the center of the adult E3–E12 diet heatmap. R, rostral; L, lateral. One observation/animal was obtained and analyzed for data shown in F and H–J.