title: A comparative study of recording procedures for motor evoked potential signals.
abstract: Motor evoked potential (MEP) signals serve as an objective measure of the functional integrity of motor pathways in the spinal cord. Hence, they provide a reliable assessment of the extent of spinal cord injury (SCI). There are two methods currently being used for serial MEP recordings in rats: a low-frequency and a high-frequency method. In this paper, we compared the two methods and determined the better method for MEP recordings. We also compared the effect of two anesthetic agents - inhalational isoflurane and intraperitoneal ketamine - on the MEP signals. We found that under ketamine anesthesia, low-frequency stimulation led to more consistent results, while high-frequency stimulation required greater stimulation intensity and was prone to unwanted side-effects including excessive head twitches. We further found that isoflurane anesthesia severely depressed the MEP response for both low-frequency and high-frequency stimulation which rendered the resulting signal unusable.
authors: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205 USA. gracee@jhu.edu
authors: Gracee
authors: G
authors: Agrawal
authors: Shrivats
authors: S
authors: Iyer
authors: Angelo H
authors: AH
authors: All
mesh_terms: D000704:Analysis of Variance; D000758:Anesthesia / Q000379:methods; D000777:Anesthetics / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D004567:Electrodes, Implanted; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D005260:Female; D007530:Isoflurane / Q000494:pharmacology; D007649:Ketamine / Q000494:pharmacology; D051381:Rats; D011917:Rats, Inbred Lew; D012886:Skull / Q000033:anatomy & histology; D013119:Spinal Cord Injuries / Q000503:physiopathology*
chemical_list: D000777:Anesthetics; D007649:Ketamine; D007530:Isoflurane