No abstract

Noise was evaluated as an aversive stimulus in the C57BLJ6J mouse, using a simple escape/avoidance procedure in which mice could terminate noise by entering and remaining in a designated safe area (corner or side) of a square apparatus. Exposed to pulsed noise of 87.5-90 dB, mice spent 45%-50% of total corner time in the safe corner or approximately 80% of total time in the safe side. Acquisition was significantly faster with moderate intensities of pulsed noise (87.5-90 dB) than it was with high-intensity pulsed noise (100 dB). In comparisons of continuous as opposed to pulsed noise, acquisition was significantly faster with continuous (87.5-dB) noise than it was with pulsed noise, and continuous noise was shown in a choice procedure to be more aversive. Continuous noise caused significant, though not severe, suppression of activity, but pulsed noise caused virtually none. Thus, pulsed noise is a mildly aversive stimulus for C57BLJ6J mice and may have promise for the study of stress-induced behaviors in freely moving animals, but continuous noise is clearly more effective for rapid short-term conditioning.