Figure 5. Each set of three columns indicates the mean neuronal responses of the first, second, and third stimulus application at 0.9 and 1.1 MAC (mean +/− SD). Therefore, the 0.9 MAC data are from those animals in which responses were determined first at 0.9 MAC, and the 1.1 MAC data are from those animals in which responses were determined first at 1.1 MAC. At 0.9 MAC, there was a trend for the response to increase, but this was not statistically significant. There were no statistically significant changes in the responses over successive stimuli at 1.1 MAC. The second sets of responses at 0.9 and 1.1 MAC were numerically higher than the first set, but the differences were not statistically significant (data not reported).