Fig. 5. Summary of thiopental's action on the spontaneous firing rate of (A ) dorsal spinocerebellar tract (DSCT) neurons (n = 11) and (B ) spinoreticular tract (SRT) neurons (n = 6) concurrently with the induction of slow, spindle-like wave events in the electroencephalogram waveform and firing rate of neck motoneurons. Time relative to zero is indicated in minutes. Each point on each graph represents the group mean (± SD) activity (spikes per second for DSCT, SRT, and nuchal electromyogram [motoneuron] activity and events per second for slow waves in the electroencephalogram waveform induced by thiopental). Thiopental exerted depressant actions on DSCT and SRT neurons. Motoneuron activity was also depressed to a greater extent than DSCT or SRT neuron activity. The duration of slow, spindle-like events in the electroencephalogram waveform was transient when compared with the drug's depressant action on sensory tract and motoneuron activity. *Statistically significant differences from control (P < 0.05, repeated-measures analysis of variance and Dunnett test). EEG = electroencephalogram; EMG = electromyogram.