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. Author manuscript; available in PMC: 2023 Aug 1.
Published in final edited form as: Nat Neurosci. 2022 Jul 28;25(8):1071–1081. doi: 10.1038/s41593-022-01126-1

Extended Data Fig. 4. Latent inhibition: Dopamine responses to non-pre-exposed and pre-exposed stimuli do not differ in the absence of latent inhibition and converge following extensive experience.

Extended Data Fig. 4

(a) Dopamine responses did not differ between the CS+ and pre-exposed CS+ for the animals that did not show latent inhibition. (b) The peak heights (two-sided Nested ANOVA, F(1, 21)= 0.61 p=0.4449, n=30 presentations; n=5 mice), (c) the time to return to baseline (two-sided Nested ANOVA, F(1, 21)= 0.30 p=0.5888, n=30 presentations; n=5 mice), and (d) tau were not different between the CS+ and pre-exposed CS+ (two-sided Nested ANOVA, F(1, 21)= 0.60 p=0.4467, n=30 presentations; n=5 mice). (e) In the mice that showed latent inhibition, the behavioral and dopamine differences disappeared. (f) Freezing responses to the pre-exposed CS+, non-pre-exposed CS+ (CS+), and non-pre-exposed CS− (CS−) were measured on session 2 of a two session fear conditioning paradigm (RM ANOVA pre-exposure main effect, F(1.466,5.863)= 19.99, p=0.0032), the difference between the CS+ and pre-exposed CS+ disappeared on the second conditioning session (Tukey post-hoc, p=0.9979). Both the CS+ (Tukey post-hoc, p=0.0034) and the pre-exposed CS+ (Tukey post-hoc, p=0.0037) yielded a stronger freezing response compared to the CS−. (g) Averaged dopamine responses to the CS+ and pre-exposed CS+ during session 2 over all trials. (h) Dopamine responses did not differ between the CS+ and pre-exposed CS+ (Nested ANOVA, F(1, 54)= 0.42 p=0.8901, n=30 presentations; n=5 mice). (i) The time to return to baseline was not different (Nested ANOVA, F(1, 54)= 0.07 p=0.7864, n=30 presentations; n=5 mice). (j) Tau is another measure of dopamine clearance and is defined by the time in seconds for the signal to return to 2/3 of peak height. Tau was not different between the CS+ and pre-exposed CS+ (unpaired t-test, t58=0.27, p=0.78, n=30 presentations; n=5 mice). In the absence of the latent inhibition effect, dopamine response to the pre-exposed and novel CS+ do not differ. Data represented as mean ± S.E.M. ** p<0.01, ns = not significant.