pseudo-random order. Pulse and prepulse tone duration was 80 and 40 ms, respectively. The prepulse-pulse delay was 100 ms. Inter-trial-intervals were randomly selected to occur within a 10 to 15 s range. Percent PPI was calculated with the following formula: 100-[(mean startle amplitude for prepulse-pulse trials/mean startle amplitude for pulse-alone trials) × 100]. As no interaction between prepulse levels and treatment were found in the statistical analysis, % PPI values were collapsed across prepulse intensity to represent average % PPI.
