Graphs showing abundance (A) and intensity (B) of substance P-immunolabeling in striatal terminals in GPi and SN, and ENK-immunolabeling in striatal terminals in GPe of 1 month-, 4 month-, and 12 month-old wildtype and heterozygous Q140 Huntington’s knock-in mice, presented in all cases as a percent of WT mice (±SEM). Note that abundance and labeling intensity for these three fiber types does not differ significantly between Q140 and WT at any of the three ages examined, by a parametric t-test.