Changes in burst parameters after MK801 injection. For neurons that had an increase in firing rate after MK801 injection, there was a dose-dependent decrease in the percentage of spikes in bursts, mean number of bursts per min, and mean number of spikes per burst. However, for neurons in the 0.01 mg/kg MK801 group, there was a significant increase in the mean number of bursts per min and mean intraburst frequency. Asterisks indicate significant difference compared to saline by ANOVA with the Bonferroni post hoc test (P < 0.05).