Fig. 3.

DiI (1,1′, di-octadecyl-3,3,3′,3′,-tetramethylindocarbocyanine perchlorate) labeling of spinal projections of afferents in control and mutant mice at postnatal day (P) 0–P1. A: Extent of the central projections of sensory axons from dorsal spinal roots (DRs) into the spinal cord at different lumbar (L2–L5) segmental levels in Er81^−/− mice. B: Spinal projections of afferents at the L4 level in wild-type (WT), Er81^−/−, myoNT3;Er81^−/−, and myoNT3 mice. Arrows in each panel indicate the normal location of Ia afferents in WT mice, although these projections are largely absent in Er81^−/− mice. Locations of α-motoneurons (MNs) are indicated with asterisks. Some MNs are also DiI (1,1′-dioctadecyl-3,3,3′,3′,-tetramethylindocarbocyanine perchlorate) -labeled in several panels. Note that more afferent projections are present at the L5 than L2 level in Er81^−/− mice and that the density of the projections is higher in myoNT3;Er81^−/− than in Er81^−/− mice. dh, dorsal horn.