Figure 2. Pavlovian transreinforcer reversal task and behavioral performance.

(A) After presentation of the CS, subjects predicted which odor they expected based on the presented CS and then identified the odor they received. (B) An example trial sequence illustrating the possible reversals. Reversals could occur throughout the task (after 4–6 presentations of a given CS) without warning, and independently for the two CS. (C) Subjects correctly predicted the upcoming odor well above chance (25%) and learned new associations quickly after a reversal (black arrow). Performance did not differ between reversal types (within vs. between category reversal). (D) Subjects accurately identified the received odor well above chance (25%) regardless of whether a reversal occurred and independent of reversal type. Error bars represent SEM.

Figure 2—figure supplement 1. Response times for odor prediction and odor identification.

Response times for odor prediction (A) and odor identification (B) during the three trials leading up to the reversal, the reversal, and the three trials post-reversal. Error bars represent SEM.

Figure 2—figure supplement 2. Respiratory responses.

(A) Breathing traces for different trial types. (B) Sniff amplitude per trial type (non-reversal, between-category reversal, and within-category reversal). Sniff amplitude differed significantly between trial types (repeated measures ANOVA: Type: F(2, 32)=4.12 p=0.033). Post-hoc t-tests revealed that the effect was driven by significant differences between within-category reversals and non-reversal trials (t(16)=-3.13, p=0.006). No difference was found between within-category and between-category reversals (t(16)=1.80, p=0.091), or between non-reversal trials and between-category reversals (t(16)=-0.63, p=0.535). (C) Sniff latency (time to peak) per trial type. There were no significant differences between trial types (repeated measures ANOVA: Type: F(2, 32)=0.89 p=0.405). Error bars represent SEM.