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. 2009 Dec 16;29(50):15713–15720. doi: 10.1523/JNEUROSCI.2620-09.2009

Figure 1.

Figure 1.

A, Impaired extinction of cued fear. Freezing behavior during the CS+ across R1–R6, E, and RS (standard training). Freezing in Gad65+/+ mice declined from R1 to R6 and remained low during E. Gad65−/− mice displayed pronounced freezing across all sessions with the exception of R6. Very little freezing was observed in unpaired controls of either genotype. Asterisks indicate between-genotype differences. B, Generalization of fear. Freezing behavior during the CS− across R1–R6, E, and RS (standard training). Gad65+/+ mice showed very little freezing to the CS− across all sessions. Gad65−/− mice exhibited high freezing to the CS− early in extinction training (R1, R2) and during the extinction retention test (E). C, Weak training. Freezing behavior during the CS+ across R1–R6, E, and RS. Gad65−/− mice were similar to Gad65+/+ mice at R1 and E. However, extinction learning across R1–R6 remained impaired in Gad65−/− mice. D, Unaffected extinction of contextual fear. Both genotypes showed similar levels of freezing after conditioning (R1), whereas no-shock controls for both genotypes showed no freezing. No differences were seen between genotypes across extinction training. All data are expressed as mean ± SEM. Asterisks indicate between-genotype differences. *p < 0.05, **p < 0.01, ***p < 0.001.