Figure 6.

Decreased object recognition memory in aged DAL mice. ALDH2 deficiency impaired memory for object recognition. A, Training for visible object recognition. During 10 min of training, two objects (a and b) were presented to a mouse. C57BL/6 mice, which were used as a control (CTL), and all DAL mice had equal preferences for two objects, a and b. Filled bars, Aged mice; open bars, young mice (see Materials and Methods). The numbers on the bars indicate the number of animals examined. B, Testing for novel object recognition. During 5 min of testing, one of the conditioned objects was replaced by a novel object (c). Young mice and aged CTL mice, but not aged DAL mice, showed recognition memory 1 d after a training session. ^#p < 0.05, ^##p < 0.01 versus index in a training session; *p < 0.05, **p < 0.01.