Comparison of two measures of learning performance, learning speed (LS) and final discrimination performance (final DP).

<p>LS is identified as the first day with significant performance, i.e. with a significant difference of CS+ and CS– induced hurdle jumps (fourfold table χ2-test, note that a smaller value reflects faster learning), final DP is a measure of how well the animals finally learn to discriminate the stimuli and is defined as the median of the differences between CR+ and CR- across the last 8 training sessions of each individual animal (cf. Methods). Given are median values and quartiles for animals that were trained to discriminate periodicities of 20 Hz vs. 40 Hz (blue data points) or 160 Hz vs. 320 Hz (red data points). Between-group comparisons for LS and final DP were carried out using Bonferroni-corrected Mann-Whitney U-statistics, p-level:.*p<0.05, ***p<0.001.