Figure 4.

Early expression of Calbindin (Calb1) and Calretinin (Calb2) expression in the MNTB at P8 (A,A’). Calb1 expression increases in the LSO by P46 (B,B’). At 1 year of age, there is minimal Calb1 expression in the LSO and SPN. Calb2-positive fibers form a calyx of Held in the MNTB (C–C””). Within the MNTB, there are larger Calb1-positive cells close to the cochlear nucleus (~229 μm²) compared to much smaller cells closer to the midline (~132 μm²). Our expression shows upregulation of Calb2 in the MNTB (compare P8 with P46) that progressively upregulates with Calb1. Note that fewer MNTB are shown in a single section that likely comes about through lateral distributions. P: postnatal, Bar indicates 100 μm in (A–C,C’), 10 μm in (C”’,C””).