Fig. 1: FusΔNLS/+ mice display increased nocturnal spontaneous locomotor activity and cognitive defects.
a, b Line graphs represent mice home cage activity–actimetry over three consecutive days at 4 months (a) and 10 months (b) of Fus+/+ (black) and FusΔNLS/+ (orange) male mice N = 11 for Fus+/+ and N = 10 for FusΔNLS/+ mice at 4 months and N = 15 for Fus+/+ and N = 14 for FusΔNLS/+ mice at 10 months. Repeated measures Two-way ANOVA followed by Sidak for multiple comparisons, with time and genotype as variables. P = 0.0027 at 4 months and p = 0.038 at 10 months for genotype effect. Data are presented as mean ± SEM values of activity score per hour. c Schematic illustration of the Morris water maze (MWM) experimental strategy (paradigm). Mice were subjected to a five-day training period and tested for spatial memory retention in a probe trial (60 seconds) 18 days after the last acquisition. The probe trial was then followed by two extinction tests, performed at 2 h intervals. d, e Line graphs represent latency (in seconds) (d) and total distance swam (in meters) (e) to find the hidden platform during acquisition of 10-months-old Fus+/+ (black) and FusΔNLS/+ (orange) male mice. Both genotypes improved similarly their performance between day 1 and 5. N = 10 for Fus+/+ and N = 11 for FusΔNLS/+ mice. Data are presented as mean ± SEM values of four trials per day of training. A two-way repeated measure analysis of variance (ANOVA) (genotype * days) was conducted to determine the effect of genotype on learning over time. No significant effect of genotype is observed. f Bar graphs represent the time spent in the target quadrant (Target) and the average of the time spent in the other three quadrants (Others) during probe trial. Dashed line indicates chance level (15 seconds per quadrant; i.e., 25%). N = 10 for Fus+/+ and N = 11 for FusΔNLS/+ mice. Data are presented as mean ± SEM. Both genotypes were significantly above random but FusΔNLS/+ mice performed significantly worse than Fus+/+ littermates ($, p < 0.01, One sample t-test was used to compare to a chance level, Target quadrant: p = 0.0008 for Fus+/+ and p = 0.006 for FusΔNLS/+). Genotype comparison was made using One-way ANOVA; F(1,19) = 6.33, p = 0.0208. g, h Bar graphs represent the time spent in quadrants (Target vs Others) during the first (g) and the second (h) extinction test ($, p < 0.05 vs chance levels). One-way ANOVA for genotype effect (F(1,19) = 0.56, p = 0.46) (g), (F(1,19) = 0.27, p = 0.6) (h) and One sample t-test was used to compare to a chance level, (Target quadrant: p = 0.025 for Fus+/+ and p = 0.22 for FusΔNLS/+) (g), (Target quadrant: p = 0.08 for Fus+/+ and p = 0.09 for FusΔNLS/+) (h). N = 10 for Fus+/+ and N = 11 for FusΔNLS/+ mice, with same mice as panel f. Data are presented as mean ± SEM. Source data are provided as a Source Data file.
