Characteristics of Mid- to Long-Latency Spinal Somatosensory Evoked Potentials following Spinal Trauma in the Rat

The purpose of this study was to develop and implement a new technique for repeated monitoring of spinal mid- to long-latency somatosensory evoked potentials (SpSEPs) during sciatic nerve stimulation following recovery from spinal cord injury (SCI) in rats. Results of this study showed significant reproducibility of SpSEP components between specimens (analysis of variance [ANOVA], p > 0.05) and recording days (ANOVA, p > 0.700) using this technique. SpSEP amplitudes were significantly reduced (similar to 50% of uninjured amplitude, ANOVA, p < 0.001) following SCI and remained depressed for 10 weeks post-injury. SpSEP amplitude following high-intensity stimuli (> 1mA) correlated with BBB locomotor score (Pearson, R > 0.353, P < 0.001). Characteristics of the mid- to long-latency SpSEPs suggest these components may reflect the integrity of the lateral pain pathway within the spinothalamic tract (STT). The technique and data presented in this study may be useful in future studies aimed at quantifying spinal cord integrity following injury and treatment using the rat model of SCI.