Supplementary Figure 2: Short RTs and processing delays.
(a) Each plot shows the cumulative distribution of RTs for a given difficulty (absolute value of ILD) for the three ABLs (RTs merged across rats). The shape of the distribution for the shorter RTs is the same across all conditions. This is presumably due to the fact that sound onset after central-port entry was to some extent predictable (fixation period was drawn from a uniform distribution between 300 and 350 ms) and to the fact that we did not impose a minimum RT. These short, condition-independent RTs are thus the result of anticipation. (b) To detect the earliest time where RTs become condition-dependent, we run a two tailed Kolmogorov-Smirnoff test comparing the RTs for the fastest and slowest conditions (|ILD| = 6 dB and ABL = 60 dB SPL versus (|ILD| = 1.5 dB and ABL = 20 dB SPL) as a function of the maximum RT included in the comparison. This panel shows the p-value of the test. We defined RTmin as the value at which this comparison becomes significant (90 ms, p<0.05). This value is shown as a dashed vertical line in (a) and (c). Since we are interested in the stimulus-dependence of RTs, we excluded from all analyses RTs smaller than RTmin. (c) Same as (a) but comparing the cumulative RTDs across ILDs for each ABL separately. As expected, the distributions start to diverge later for fainter sounds. However, it is obvious that this unspecific intensity-dependent delay cannot account for the changes in the RTD as a function of ABL shown in (a). None of our results changes qualitatively if we define a separate RTmin for each ABL.
