Analysis of spinal cord evoked potential and locomotor function during acute spinal cord compression in cats

The aim of this study was to investigate whether or not conductive spinal cord evoked potentials and spinal cord function change correspondingly with each other. The relationship between conductive spinal cord evoked potentials and locomotor function during acute spinal cord compression in animals was investigated. In decerebrate cats, controlled locomotion can be induced by electrical stimuli in the mesencephalic locomotor region. Conductive spinal cord evoked potentials were recorded at the L3 level of the spinal cord and stimuli were given at the T4 segment. The locomotor function was evaluated through electromyograms of the hind limbs. By compressing the spinal cord at L1, both the conductive spinal cord evoked potentials and the locomotor function gradually decreased. When the first negative potential amplitude of conductive spinal cord evoked potentials was decreased to half the level found in normal cats, locomotor function was injured irreversibly. These results showed that changes in the conductive spinal cord evoked potentials were related to changes in locomotor function. The 50% level of the first negative potential amplitude was considered to be the critical level at which irreversible spinal cord paralysis occurred in the cats.