Effect of Treadmill Training Protocols on Locomotion Recovery in Spinalized Rats

Abstract

Both treadmill training and epidural stimulation can help to reactivate the central pattern generator (CPG) inthe spinal cord after a spinal cord injury. However, designing an appropriate training approach and astimulation profile is still a controversial issue. Since the spinal afferent signals are the input signals of CPGin the spinal cord, it can be concluded that the number of input afferent signals can affect the quality ofmovement recovery, such a phenomenon is in accordance with Hebbian theory. Therefore, at first in thispaper, through some simulation studies on a model of CPGs, the effective influence of increasing theafferent input weight onactivatingCPGmodel was certified. Then, the performance of twodifferent types oftreadmill training along with epidural stimulation was compared. The numbers of spinal afferents involvedduring each designed training approach were different. Experiments were conducted on two groups ofspinalized rats. Three quantized integer qualitative measures, with 0–2 scales, were envisioned to evaluatethe performance of training protocols. According to the experimental results, the assigned scales to the ratsusing the training approach involving more afferents, the rats have been creeping on a treadmill, was 2. Also,the assigned scales to the rats using the training approach involving less afferents, the rats have beenperforming bipedal locomotion, was 0 or 1. Such experimental results coincide with achieved simulationresults elucidating the effect of increasing the afferent input weights on activating CPG model.