Shuttlebox avoidance by rats using white noise intensities from 90-120 db SPL as the UCS

Hooded rats in 4 groups (10 M, 10 F each) were given shuttlebox avoidance training, 25 trials a day for 6 consecutive days, using a compound light-click warning signal and white noise as an aversive unconditioned stimulus at either 90, 100, 110, or 120 db SPL. Avoidance performance was an inverted U-shaped function of noise level. Females were significantly more active than males at each noise level, but although females performed more avoidance responses than males at each level, this sex difference was not significant. Avoidance response latencies were relatively invariant across training sessions for each group, as were escape responses latencies for the 100- and 110-db groups. Escape response latencies for the 90- and 120-db groups increased across training sessions. Shuttlebox performance as a function of increasing white noise UCS level is, in most respects, similar to performance obtained with increasing shock intensities.