Figure 2.

Illustration of the main events (a), response categories and outcome (b) of the SAT as used in rats and illustration of performance data from SAT and dSAT sessions (c-h; base task performance: black lines, squares; distractor condition: orange lines, triangles; data from Wistar rats; the presence of the distractor in blocks 2 and 3 is indicated by the oranges block on the abscissa). The performance in signal and non-signal trials is collapsed into one measure of performance, the SAT/dSAT scores (Figure 2h). SAT/dSAT scores are calculated for each signal duration (e.g., 500, 50, 25 ms; SAT/dSAT_500,50,25) on the basis of the relative number of hits (h) and false alarms (f), in accordance with this formula: (SAT/dSAT=[(h-f)/2(h+f)-(h+f)²]) and then averaged over all signal durations, yielding a single overall score (Figure 2h). The formula is a variation of the non-parametric calculation of signal sensitivity (SI; Frey & Colliver, 1973). SI is based on the probabilities for hits and false alarms. In contrast, the calculation of SAT/dSAT scores is based on the relative number of hits and false alarms, thereby removing the confounding effects of omissions from this performance measure. SAT/dSAT scores range from -1 to +1. Values of 0 indicate randomized lever section, +1 indicates perfect response accuracy in signal and non-signal trials, and -1 indicates complete inaccuracy. The scores shown in Figure 2h are averaged over all signal durations and depicted by block to visualize the contrast between SAT and dSAT scores.