Fig. 1.

Instrumental training for tone detection task. (A) Operant chamber used for training rats in tone detection task. Devices include a nose poke, food pellet dispenser, and speaker. The chronological sequence of the instrumental detection task for a 5-kHz 50-dB tone is shown. (B) For rats in the 14-d group, d′ results vs. number of training days. Thin lines plot results from individual animals, whereas the thick line shows the group average. ANOVA shows a significant effect of training day on d′ (P < 0.005), and post hoc testing finds that days 1 and 2 are significantly lower than all days, with d′ greater than or equal to that on day 4.