Figure 4.

Glutamatergic neurons of the CnF contribute more efficiently than those of the PPN to spontaneous locomotor recovery of the ipsilesional hindlimb after SCI

(A) Combination of electromyographic (EMG) recordings with short pulses (10 ms) of photostimulation to probe changes in motor efficacy of glutamatergic CnF or PPN neurons to locomotor recovery after SCI.

(B) Color-coded matrices illustrating the locomotor score of the ipsilesional left hindlimb of mice before and after SCI. No significant difference between CnF and PPN mice (n = 6 CnF and n = 7 PPN mice, Mann-Whitney tests, p = 0.80 at week 1, p = 0.76 at week 4, and p = 0.95 at week 7).

(C) Example of background EMG activities of the ipsilesional flexor (tibialis anterior) and extensor (gastrocnemius lateralis) muscles during treadmill locomotion with a 10-ms pulse photostimulation. The difference in the density of motor spikes evoked post- vs. pre-photostimulation identified whether responses were excitatory, inhibitory, or absent (indicating a failure).

(D–F) Proportion of failure (D), excitatory (E), and inhibitory (F) motor responses evoked in the ipsilesional flexor muscle during the swing phase as a function of the locomotor score of the ipsilesional hindlimb over the course of spontaneous locomotor recovery after SCI. See also Figures S5–S8.