Fig. 7. Summary of ketamine's action on air puff–evoked activity recorded from trigeminal sensory nuclear complex (n = 6) and trigeminothalamic (n = 2) neurons. This graph was constructed as described in  fig. 4,. Overall, air puff–evoked activity was suppressed by 45% 5 min after the onset of drug administration. The time course and magnitude of ketamine's effects on air puff–evoked responses was equivalent that observed for tooth pulp–evoked responses (see  fig. 8 ).  Asterisks indicate statistically significant differences from control (  P < 0.05 on repeated-measures analysis of variance, Dunnett's method).