Fig. 3.

a Spatial learning performance in the Morris water maze during the acquisition phase of adult male mice exposed to 2 h/day, 5 h/day, and 7 h/day for 12 weeks when compared with the control group (P < 0.038 and P < 0.001, respectively). b Memory retention during the probe trial of adult male mice exposed to Control, 2 h/day, 5 h/day, and 7 h/day for 12 weeks when compared with the control group. *P < 0.05, **P < 0.01. Data are shown as mean 10 SEM