Data from: Operation of spinal sensorimotor circuits controlling phase durations during tied-belt and split-belt locomotion after a lateral thoracic hemisection

Locomotion is controlled by spinal circuits that interact with supraspinal
drives and sensory feedback from the limbs. These sensorimotor
interactions are disrupted following spinal cord injury. The thoracic
lateral hemisection represents an experimental model of an incomplete
spinal cord injury, where connections between the brain and spinal cord
are abolished on one side of the cord. To investigate the effects of such
an injury on the operation of the spinal locomotor network, we used our
computational model of cat locomotion recently published in eLife (Rybak
et al., 2024) to investigate and predict changes in cycle and phase
durations following a thoracic lateral hemisection during treadmill
locomotion in tied-belt (equal left-right speeds) and split-belt (unequal
left-right speeds) conditions. In our simulations, the “hemisection” was
always applied to the right side. Based on our model, we hypothesized that
following hemisection, the contralesional (“intact”, left) side of the
spinal network  is mostly controlled by supraspinal drives,
whereas the ipsilesional (“hemisected”, right) side is mostly controlled
by somatosensory feedback. We then compared the simulated results with
those obtained during experiments in adult cats before and after a
mid-thoracic lateral hemisection on the right side in the same locomotor
conditions. Our experimental results confirmed many effects of hemisection
on cat locomotion predicted by our simulations. We show that having the
ipsilesional hindlimb step on the slow belt, but not the fast belt, during
split-belt locomotion substantially reduces the effects of lateral
hemisection. The model provides explanations for changes in temporal
characteristics of hindlimb locomotion following hemisection based on
altered interactions between spinal circuits, supraspinal drives, and
somatosensory feedback.