Figure 1. Contextual and auditory cued fear conditioning tests in euthyroid and adult-onset hypothyroid rats.

(A) Schematic representation of the experimental design. Shadowed areas indicate periods of animal manipulations. (B) Conditioning session for auditory and contextual cues. No differences were found in neither pre-shock nor post-shock periods. (C) Contextual fear test sessions 1 day, 1 week and 3 weeks after conditioning. H rats showed higher freezing levels than E rats, which reach statistical differences 1 day and 3 weeks after conditioning. (D) Auditory cued fear testing 2 days, 1 week and 3 weeks after the conditioning session. H rats showed higher freezing levels during the tone period than their E counterparts at every test session after conditioning. Plot bars show means ± SEM. *, p<0.05; **, p<0.01; NS, no significant. n = 8 per group.