Skip to main content
. 2011 Jul 27;6(7):e22600. doi: 10.1371/journal.pone.0022600

Figure 2. Freezing behavior and theta synchronization in naive 5-HTT mice at different stages of fear extinction.

Figure 2

A) Freezing behavior during the first CS+ across R1-R6 and E in all three genotypes. Freezing in all the three genotypes declined from R1-R6, indicating the standard extinction of fear memory. Twenty four hours later, when all the three genotypes were tested for fear extinction recall, 5-HTT−/− mice showed significant impaired extinction recall (E), represented by significantly higher levels of freezing compared to 5-HTT+/− and 5-HTT+/+ mice (p<0.001). B) Stimulus-related theta correlation in 5-HTT mice at different stages of fear extinction. Averaged cross-correlation during the presentation of the first CS+ between LA and IL of mPFC during extinction (R1-R6) and extinction recall (E) in 5-HTT naive mice is shown. When compared with 5-HTT+/+, 5-HTT−/− mice showed significantly increased cross-correlation during extinction training (note significant at R4 and R6; p<0.05). In 5-HTT−/− mice, the correlation values remained high across the extinction training and being significantly higher than for 5-HTT+/+ mice during E. C) Freezing-related averaged cross-correlation during the first CS+ between LA and IL of mPFC during extinction training (R1-R6) and extinction recall (E) in 5-HTT naive mice. Note, that the 5-HTT−/− mice showed significantly increased cross-correlation during extinction recall (p<0.05, compared to 5-HTT+/− and 5-HTT+/+− mice). Values are mean ± SEM; *p<0.05, #p<0.001.