Why Variability Facilitates Spinal Learning

This study investigates how variability in movement affects spinal cord learning in rats with spinal cord injuries. The rats were trained to step on a treadmill using two different robotic assistance methods: one with a fixed trajectory and another with assist-as-needed (AAN). The AAN method, which allowed for more natural variations in the stepping motion, resulted in better coordination between the flexor and extensor muscles compared to the fixed trajectory method. This suggests that some level of variability is crucial for effective spinal learning. The findings imply that rehabilitation strategies should incorporate variability to optimize the recovery of locomotor function after spinal cord injuries. By allowing for natural variations, the spinal cord can better relearn and adapt its neural control mechanisms.

• 1
  The assist-as-needed (AAN) training paradigm resulted in more normal flexor-extensor activation patterns compared to the fixed-trajectory paradigm in spinal cord transected rats.
• 2
  The fixed-trajectory paradigm led to a higher amount of coactivation between antagonistic muscles (soleus and TA) compared to the AAN paradigm.
• 3
  Robotic corrections during the swing phase were approximately threefold greater in the fixed-trajectory group compared to the AAN groups.