Plasticity of Corticospinal Neural Control after Locomotor Training in Human Spinal Cord Injury

Figure 2

TA MEP modulation during stepping before and after locomotor training in SCI. The tibialis anterior (TA) motor evoked potential (MEP) amplitude before (dashed line) and after (solid line) 60 body weight-supported treadmill training (BWSTT) sessions is indicated as a function of the step cycle during body weight-supported (BWS) assisted stepping for one patient with American Spinal Injury Association (ASIA) Impairment Scale (AIS) D (49 yo female, 5 years after injury, T5–7). The TA MEP was evoked randomly every 3 to 4 steps at 1.3 times TA MEP threshold while stepping at 0.5 m/s with 50% BWS before training and at 0.89 m/s with 20% BWS after training. MEP threshold was established with subject standing at equivalent levels of BWS utilized during stepping. The step cycle was divided into 16 equal time windows or bins. Stance phase duration is identified by the grey region. Bin 1 corresponds to heel strike. Bins 8, 9, and 16 correspond approximately to stance-to-swing transition, swing phase initiation, and swing-to-stance transition, respectively.