Startle/pre-pulse inhibition. The startle and pre-pulse inhibition tests were performed using a Hamilton-Kinder SM100 startle chamber inside a 14 in L × 10.875 in W × 19.5 in H sound-attenuating chamber. Animals were placed in the chamber with a 65 dB background white noise and allowed to habituate. Over an approximately 15 min session, 55 pseudo-random trials were given. A 120 dB white noise burst was used as the acoustic startle stimulus. Pre-pulses were 70, 80 and 85 dB white noise bursts which preceded the startle stimulus by 10 milliseconds. Startle responses to the startle stimulus and to each of the pre-pulse dB levels were measured.
