Fig. 3.

HSL^−/− mice show memory impairment while exploratory and anxiety-like behaviors are preserved. A: Schematic representation of the Barnes maze with holes numbered 1 to 10 from the target hole (T) and divided in four quadrants. B: Learning to find the target hole over the 8 acquisition days was not affected by genotype. C: Training in acquisition day 1 was followed after habituation to the maze and allowed to identify increased latency and walked distance until entering the target hole, an increased number of errors (nontarget hole searches) in HSL^−/− versus wild-type mice. D: Compared with controls, HSL^−/− mice utilized more often a random than serial hole search during the 8-day training period. E: Relative to controls, HSL^−/− mice searched less holes in the target quadrant, took longer time to reach the target hole for the first time, and spent overall less time in the target quadrant during the probe session. Dashed line at 25% represents random exploration (chance). F: Fraction of successful spontaneous alternations (consecutive entries in the three arms) in the Y-maze was lower in HSL^−/− mice than controls, while showing similar number of entries in the maze arms. Dashed line at 0.5 represents random arm entries. G: Genotype had no effect on open-field exploration, with similar number of quadrant crossings, rearing events (vertical explorations), walked distance in the arena, and time spent in the arena center. H: Elevated plus maze test showed no effect of genotype on either time spent and number of entries in closed and open arms or total distance walked in the maze. Data are represented as mean ± SEM in line graphs of n = 10–11 and as individual data points and mean ± SD in bar graphs. Symbols over data points indicate significant differences between control and HSL^−/− mice (∗P < 0.05 and ∗∗P < 0.01) based on Student's t-tests or Fisher’s least significant difference post hoc comparison test following the presence of significant effects of genotype in ANOVA tests.