In Exp. I 8 rats received a 119-db tone burst at 9000 cps, alone or preceded by an 85-db white-noise burst with a 40-, 160-, or 1000-msec separation. In Exp. II with 7 rats, the tone was given alone or preceded by a light flash at a 20-, 40-, 80-, 160-, 320-, or 640-msec separation. In both experiments the startle response to the tone was partially inhibited by the prestimulus, the magnitude of inhibition decreasing with increased stimulus separation. The similarity of the 2 functions suggests that the inhibitory process responsible for startle diminution is activated by multiple sensory systems and is not a specific auditory refractory process. (PsycINFO Database Record (c) 2006 APA, all rights reserved)