Figure 6. Increased Incidence of Heteronymous Connections Following Transmission Blockade.

(A) Percentage of motor neurons contacted by TA sensory afferents in p21 WT and p18 Pv^TeNT mice (WT: data as in Figure 1C. Pv^TeNT: n = 3-5 mice). Difference in percentage of EDL motor neurons receiving TA input is significant at p = 0.003 (Student’s t-test).

(B) Percentage of motor neurons contacted by TA sensory afferents in p7 WT and Pv^TeNTmice (WT: data as in Figure 1E. Pv^TeNT: 3-4 mice). Difference in EDL motor neurons receiving TA input is significant at p = 0.008 (Student’s t-test).

(C) Density of TA sensory input to TA motor neurons in p7 wild-type and Pv^TeNTmice. Each point represents one motor neuron (WT: n = 11 MNs, as in Figure 1F. Pv^TeNT: n = 14 MNs). Red lines indicate mean ± SEM for motor neurons receiving TA input.

(D) Density of TA sensory input to EDL motor neurons in p7 wild-type and Pv^TeNT mice (WT: n = 19 MNs, as in Figure 1F. Pv^TeNT: n = 20 MNs). For EDL motor neurons contacted by TA sensory afferents, the density of contacts increases ~2-fold (p = 0.05; Student’s t-test).

(E) In the absence of neurotransmission, sensory afferents contact a greater proportion of heteronymous motor neurons and initially contact each heteronymous neuron with increased density.

All data reported as mean ± SEM. For related data, see also Figure S6.