Figure 1. M- and F-wave amplitudes (mV) after equilibration at several sequential mixtures of nitrous oxide and isoflurane in study 1. Baseline is 1.0% isoflurane; nitrous oxide concentrations are added to baseline. Steps 3 and 4 are recorded at 15-and 30-m intervals, respectively, after nitrous oxide (but not isoflurane) was discontinued. Data are plotted as mean+/-SD. *significant change.