Figure 7. Up-ramps are behaviourally more salient than down-ramps.

(a) Sketch of the head-fixed sound-reward association task. (b) Histograms of lick rates normalized to the baseline rate during the first and seventh days of training to the up- (right) and down-ramps (left). Average across all mice (n=6 per group). (c) Ratio of the post- and pre-stimulus lick rates over training days for the up- (blue) and down-ramps (orange) (mean±s.e.m.), showing increased sound-locked licking for up-ramps, Friedman test, P=3.7 × 10⁻¹⁰, n=6 per group). (d) Schematic of the distractor avoidance learning task. Freely moving mice first learn to lick at a spout after an S+ sound to get a reward, then an S− sound is added and mice learn to stop licking after this sound. (e) Typical average infrared beam break signal (5 V=beam broken, 0 V=beam intact) with respect to S+ and S− sound onsets for a mouse on the first, second and fifth training days. (f) Examples of global performance learning curves (mean of S+ and S− performance) for the Go/NoGo distractor avoidance task. (g) Learning phase duration when either the down- (left) or the up-ramp (right) is the S− stimulus (mean±s.e.m., n=12 per group, P=0.0046, Kolmogorov–Smirnov test). The learning phase duration if defined as the time necessary to go from 20 to 80% of maximum performance above chance level (that is, >50% correct) and is measured on the sigmoid fitted to the learning curve.