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. 2015 Sep 2;41(1):45–57. doi: 10.1038/npp.2015.224

Figure 1.

Figure 1

SEFL causes anxiety phenotype on the open field test, exaggerated startle to white noise, and a depressive-like phenotype in the forced swim test. (a) Experimental design. We developed a modified version of the open field test that has been validated for anxiety testing (Godsil and Fanselow, 2004; Godsil et al, 2005). The open field test consisted of three phases: (1) 4 min of dark, (2) 4 min of light and (3) 4 min of dark. Locomotion, defined as the number of crossovers, was quantified during the 12-min test. (b) Open field test. Pre-exposure to shock significantly decreased the number of crossovers during phase 1, the first four dark minutes of the open field, p<0.005. There was no effect of pre-exposure to shock on the number of crossovers during phase 2, minutes 5–8. Pre-exposure to shock decreased in the number of crossovers during phase 3, p<0.05. Therefore, previously shocked rats showed reduced exploratory activity than controls when placed in a dark open field. When bright lights turned on at one end, the rats retreated to the dark end and reduced activity similar to controls. However, when the lights went out, unlike controls, they remained in the dark corner and did not increase exploration. The open field test did not affect the context tests in either the stress or conditioning contexts (data not shown). (c) Experimental design for exaggerated startle test. Instead of 1-shock in conditioning context on Day 2, white noise (92 dB, 1 s) was given. (d) Freezing (+SEM) for baseline on Day 2, 5 min post-noise on Day 2, and context test on Day 3. Previously stressed rats showed a pronounced freezing response to a loud noise; this reaction was not seen in unstressed controls, **p<0.01 (mixed-factorial ANOVA). Upon return to the noise context the following day without noise, the stressed rats showed a small but statistically reliable increase in freezing relative to controls, *p<0.05. (e) Experimental design. Training (Day 4) and testing (Day 11) sessions for forced swim test were 5 min. Water temperature was 77 °F, and the apparatus dimensions are 74 cm × 36.5 cm. (f) Time spent immobilized (sec+SEM) on Day 4, and time spent immobilized (sec+SEM) on Day 11. *p<0.05 (one-way ANOVA).