Figure 1. Effects of pentobarbital (75 [micro sign]M) on spontaneous action potential firing of a neocortical neuron. (A) Extracellularly monitored firing patterns before (Control), 12 min after the onset of pentobarbital application (Pentobarbital), and 25 min after removing the anesthetic (Wash). The traces on the left show typical records about 15 s in duration. On this time scale, it is difficult to resolve single action potentials. The bursts indicated by the arrow are shown on an extended time scale (right). At this resolution, the effect of the anesthetic is evident. (B) Interspike interval histograms derived from the firing patterns recorded before (upper trace), during (middle trace) and after (lower trace) pentobarbital application. The data are plotted on a log-log scale. (C) The time course of the intraburst discharge rates were calculated from averaged bursts in the absence and presence of pentobarbital. Results are given as mean values +/- SE.