Contextual fear conditioning and extinction in FMR1−/− mice and WT littermates.

<p>(A) Acquisition of contextual fear conditioning. Mice were placed in a context for 3 min and received a foot shock every 60 sec for 5 times. Mice significantly increase freezing responses when compared to baseline (BL) measures before US presentation **<i>p</i><0.01; ***<i>p</i><0.001 <i>vs.</i> baseline (pairwise comparison test). (B) Extinction training. Mice underwent 3 extinction sessions with and interval of 30 min on day 2. *<i>p</i><0.05; **<i>p</i><0.01; ***p<0.001 (genotype effect). (C) Retention test. Freezing behavior was measured on day 3 and day 8 to evaluate long-term extinction memory *p<0.05; **p<0.01 (genotype effect). Data are expressed as mean ±s.e.m.