**5. Conclusions**

In conclusion, this research characterizes the frequency content of intramuscular EMG signals recorded pre- and post-TSCI in a validated NHP model. The EMG data were collected in a longitudinal nature and were obtained from the left- and right side of the Macaca fasicularis tail muscles engaged in the dynamic/free activity. In the absence of the TSCI, the EMG data demonstrated an asymmetry activation of the two sides; this is consistent with the human phenomenon of limb preference and/or dominance. Perturbation with an experimental lesion resulted in a clear EMG consequence. Of note, the effect of the lesion was different on the left and the right side. Also, there is a preliminary inference that treatment with a combination of TRH, selenium and vitamin E may improve recovery. The results indicate that the *RP* of the decomposed EMG data adds a new dimension to the evaluation of impairment and recovery in this NHP model of experimental TSCI. This analysis might lead to a new assessment index for motor unit activity and progression of recovery from TSCI.

**Author Contributions:** Conceptualization, F.M., H.A.A., S.N., W.A.G., D.L.R., and J.B.S.; Methodology, F.M.; Data Acquisition, K.B., H.S., D.R.S., W.A.G., A.F.H., and S.N.; Writing—original draft preparation, F.M., S.N., H.A.A.; Writing—review and editing, F.M., S.N., H.A.A., N.S., E.S., H.S., K.B., D.R.S., W.A.G., A.F.H., D.L.R., J.B.S.; Project administration, H.S., K.B., W.A.G., A.F.H., S.N.; Funding acquisition, S.N.

**Funding:** This research was funded in part by the Office of The Director, National Institutes of Health, under Award Number P51OD011106 to the Wisconsin National Primate Research Center, University of Wisconsin-Madison. This research was conducted in part at a facility constructed with support from Research Facilities Improvement Program grant numbers RR15459-01 and RR020141-01. The New England Primate Research Center was the recipient of NIH Grant 5P51RR000168. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

**Conflicts of Interest:** The authors declare no conflict of interest.
