Figure 5
Multifactorial behavioral assessment in SCI rodents. (a) Bipedal stepping on treadmill (speed: 10 cm/s) induced by 40 Hz sub-threshold (~0.55 V) and threshold (0.8 V) EES, in SCI rat 3 weeks after T8 transection. MfBA was performed based on several outputs: open field trajectory, force vectors, kinematic, EMG response with muscles antagonist’s correlation, and fMEP with analysis of individual motor evoked responses performed during stepping facilitated with different stimulation intensities. Grey area on EMG indicates the interval taken for fMEP analysis. Dash-line rectangle on fMEP highlights monosynaptic and polysynaptic components of fMEP. Scale: EMG, 1 s and 2.5 mV. fMEP, time: 5 ms and amplitude: 0.5 mV, and fMEP-AVG, amplitude: 0.1 mV. On fMEP analysis, the lowest line corresponds to the earliest time point. (b) Principal component (PC) analysis was applied on the measured variables (n = 34) across all tested modalities (for details see Sup. Table 3). The steps (n = 20) collected during sub-threshold and threshold level stimulation are represented in the new three-dimensional (3D) space created by the three first PCs (explained variance, 98%). Average distance travelled (c), forward force (d), toe height (e), EMG amplitude (f), and fMEP peak counts in TA and MG muscles (g), during sub-threshold and threshold 40 Hz stimulation presented. (*p < 0.05, **p < 0.01 and ***p < 0.001, one-way ANOVA, n = 10 steps in each condition. Data represents mean ± standard deviation).
