Dissociation of Learned Helplessness and Fear Conditioning in Mice: A Mouse Model of Depression
Fig 5
Helplessness is partly correlated with other behavioral phenotypes, but not with total locomotor activity.
(A) Sucrose preference test was performed immediately after the second LH training (1. sucrose preference) and a second time after LH testing (2. sucrose preference). Top panel: sucrose preference comparing naive mice that did not receive LH training/testing (spotted bar), resilient (white bars), and helpless mice (black bars). Bottom panel: total consumption of water and 1% sucrose solution of the same mice. Data are shown as average ± SEM; *p ≤ 0.05, (1-way ANOVA with Bonferroni post test comparing all data sets); n-values are shown in brackets. (B) Immobility time (top panel) and latency until the first 2 sec of immobility (bottom panel) in the tail suspension test are not dependent on helplessness. Data are shown as average ± SEM; n-values are shown in brackets. (C) In the open field test, learned helplessness does not change general locomotor activity, on the basis of total distance (left panel) and immobility time (second panel from the left). Helpless mice spend slightly more time in the center of the open area (second panel from the right), but latency until the center is entered for the first time is not different among the groups (right panel). Data are shown as average ± SEM; *p ≤ 0.05, (1-way ANOVA with Bonferroni post test comparing all data sets with each other); n-values are shown in brackets. All tests were carried out in PER2::LUC mice.