Author/Editor		Deletis, Vedran; Rodi, Zoran; Amassian, Vahe E
Title		Neurophysiological mechanisms underlying motor evoked potentials in anesthetized humans. Part 2. Relationship between epidurally and muscle recorded MEPs in man
Type		članek
Source		Clin Neurophysiol
Vol. and No.		Letnik 112
Publication year		2001
Volume		str. 445-52
Language		eng
Abstract		Objective and methods: Direct (D) and transynaptic, (i.e. indirect) (I) corticospinal tract (CT) discharges were simultaneously recorded epidurally with muscle motor evoked potentials (MEPs) in patients under different levels of anesthesia. The effects of the one, two or more equal electrical stimuli, applied transcranially or directly to the motor cortex, were studied at different interstimulus intervals (ISIs) to determine the optimal conditions for eliciting I and MEP responses. Results and conclusion: At anesthetic levels permiting large D and I responses to single stimuli, optimal D and I wave facilitation and MEPs occurred with two stimuli at ISIs greater than 4 ms (e.g. at 5.9 and 8 ms). When single electrical stimuli elicit only a D response, optimal MEP responses are determined by the number of stimuli and the recovery of CT fibers excitability (e.g. at an ISI of 4 ms).
Descriptors		SPINAL CORD NEOPLASMS ANESTHESIA PROPOFOL FENTANYL EVOKED POTENTIALS, MOTOR LAMINECTOMY EPIDURAL SPACE PYRAMIDAL TRACTS