Figure 1. Alterations in behavioral output in ApoD-KO and HApoD-Tg mice.
(A) Open field test on locomotor exploratory behavior in ApoD-KO mice. Both horizontal (number of squares visited) and vertical (number of rearings) activities are decreased in the ApoD-KO mice, while an anxiety-related behavior (exploration of the center of the 1 m2 arena) is not altered. N= 12 mice/genotype (6th backcross generation onto C57BL/6 background). Unpaired two-sided Student’s t-test, *p < 0.05, **p < 0.01.
(B) Open field test in HApoD-Tg mice. Vertical activity increase in HApoD-Tg mice (left panel), while horizontal activity differences are not significant (right panel). A smaller arena was used in this case, and the anxiety parameter was not measured. WT: N = 16; HApoD-Tg: N = 13 (11th backcross generation onto C57BL/6 background). Unpaired two-sided Student’s t-test, *p < 0.05.
(C) Motor learning abilities were tested as the increment of the Rotarod test score over a 2 hours interval, and is represented normalized to the score of the first test. ApoD-KO mice show a lower learning ability under normal conditions. N= 14 mice/genotype (11th backcross generation onto C57BL/6 background). Sign non-parametric test, *p < 0.05.
(D) Barnes maze test on spatial learning. ApoD-KO mice fail to increase their rate of success in finding a safe escape hole, while wild type mice learn and remember using distal spatial clues. Mice were tested daily for 70 days. Results from each five consecutive daily sessions were combined in blocks. N= 6 mice/genotype (5th backcross generation onto C57BL/6 background). ANOVA test, p < 0.0001.
(A–D) Data are represented as mean ± SD.