Emergence of Deletions during Treadmill Locomotion as a Function of Supraspinal and Sensory Inputs

During walking, the body uses a spinal network to control muscle movements. This network is influenced by signals from the brain and the body's senses. When these signals are disrupted, such as after a spinal cord injury, the activity of some muscles can fail, leading to what are called 'deletions'. This study looked at whether these muscle activity failures, or deletions, happen during real walking on a treadmill. The study also wanted to see how the brain and sensory signals affect these failures by comparing cats with intact spinal cords, partial spinal cord injuries, and complete spinal cord injuries. The research found that these muscle activity failures only occurred after spinal cord injury. These failures mainly affected flexor muscles. The occurrence of these failures was also influenced by the speed of the treadmill and the extent of the spinal cord injury.

• 1
  Deletions of flexor muscle activity only occur after spinal cord injury, not in intact animals.
• 2
  These deletions primarily affect flexor muscles and do not disrupt the timing of muscle activity in the affected muscle itself, nor in other muscles on either side of the body.
• 3
  The occurrence of deletions is sensitive to treadmill speed and the severity of the spinal cord lesion, which indicates the importance of sensory and supraspinal inputs in maintaining stable rhythmic motor activity.