Assessment of sensory function in neonatal sheep with somatosensory evokedpotentials: methodology and normative data

Fetal sheep are increasingly used as animal models for fetal surgical inter ventions such as repair of myelomeningocele. Since behavioral observations cannot provide objective information about preservation of sensory function , we have developed a technique for reliably recording somatosensory evoked potentials in neonatal sheep. We determined anatomic criteria for placemen t of recording electrodes over the somatosensory cortex using external land marks, and recorded normative data for both ulnar and posterior tibial nerv e stimulation in a series of normal neonatal sheep. The methodology and nor mative data are presented in this report; a companion paper demonstrates th e utilization of this technique in a variety of experimental fetal interven tions.