Fig. 5. Method used to analyze the effect of halothane on postsynaptic N -methyl-d-aspartic acid (NMDA)–induced excitation of E neurons (data from neuron shown in fig. 4). The NMDA dose rate that resulted in a 40-Hz net increase in peak neuronal discharge frequency (Fⁿ) at 0 minimum alveolar concentration (MAC) halothane (D^40Hz) was determined by interpolation from the dose–response curve (left panel). D^40Hzwas 3.9 pm/min. At this dose rate, NMDA increased peak Fⁿ at 1 MAC halothane by 39.4 Hz (see right panel for net increases). The 1/2 D^40Hzvalues were determined from the dose–response curves by interpolation.