Fig. 8. Comparison of recovery from ketamine-related suppression of tooth pulp– and air puff–evoked responses recorded from trigeminal sensory nuclear complex (TSNC) neurons. The difference in evoked activity (Δ Activity) was calculated by subtracting the control response obtained after normal saline administration from responses at the indicated time points after the administration of ketamine.  Closed symbols indicate statistically significant differences from control (  P < 0.05 on repeated-measures analysis of variance, Dunnett's method). There was no difference in the time course of ketamine-related suppression if threshold responses of stimulus intensity–dependent (  circles ) or stimulus intensity–independent (  squares ) TSNC neurons were compared with air puff–evoked responses (  diamonds ) of TSNC neurons. However, suprathreshold responses in stimulus intensity–dependent (  hexagons ) remained significantly suppressed for 30 min.