Test Description: occurs when a loud 120 decibel (dB) startle-inducing tone is preceded by
a softer (prepulse) tone. The PPI paradigm consists of six different trial types
(70 dB background noise, 120 dB alone, 74dB + 120 dB - pp4, 78 dB + 120 dB - pp8,
82 dB + 120 dB - pp12, and 90 dB+ 120 dB - pp20) each repeated in pseudorandom order
six times for a total of 36 trials. The max response to the stimulus (V max) is
averaged for each trial type. The percent that the prepulse inhibits the animal's
response to the startle stimulus is calculated and graphed. Animals with a 120 dB
average value equal to or below 100 are excluded from analysis.