title: Deterioration in learning and memory of inferential tasks for evaluation of transitivity and symmetry in aged SAMP8 mice.
abstract: This study examined age-dependent deficits in the learning and memory of inferential tasks, using an established senescence-accelerated mouse model in age-related brain dysfunction (SAMP8) and its genetically related inbred strain (SAMR1). The mice learned two sets of nonspatial odor-odor pairs by association learning successively (i.e., A-->B, X-->Y, then B-->C, Y-->Z). They were tested in transitive inference (i.e., A-->C, X-->Z) and symmetrical inference (i.e., C-->B, Z-->Y). In the probe test of A-->C, X-->Z transitive inference, 1-month-old SAMP8 and control SAMR1 at the same age significantly chose the alternative based on transitive inference, but 4- and 7-month-old SAMP8 performed at a random chance level, in comparison with unambiguous inference by control SAMR1 at the same ages. During the test of C-->B, Z-->Y symmetrical inference, SAMP8 at 1 month of age made errors as frequently as control SAMR1 at the same age, but SAMP8 at 4 and 7 months of age made more errors than SAMR1 at the same ages. At 4 and 7 months of age, SAMP8 made more errors than 1-month-old SAMP8. Control SAMR1 did not show such an age-related deficient. These results indicate that SAMP8 mice have age-related learning and memory deficits in the ability to perform inferential tasks. Age-related hippocampal dysfunction is suggested to be the cause of these age-related deficits in old SAMP8 mice during the performance of inferential tasks mediated by declarative memory.
authors.affiliation: Field of Regeneration Control, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan. ota@frontier.kyoto-u.ac.jp
authors.forename: Akira
authors.initials: A
authors.lastname: Ohta
authors.forename: Ichiro
authors.initials: I
authors.lastname: Akiguchi
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Seriu
authors.forename: Katsunori
authors.initials: K
authors.lastname: Ohnishi
authors.forename: Hideo
authors.initials: H
authors.lastname: Yagi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Higuchi
authors.forename: Masanori
authors.initials: M
authors.lastname: Hosokawa
mesh_terms: D000375:Aging / Q000235:genetics*; D000818:Animals; D004193:Discrimination Learning / Q000502:physiology; D006624:Hippocampus / Q000378:metabolism / Q000503:physiopathology; D007859:Learning Disabilities / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008569:Memory Disorders / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D051379:Mice; D008815:Mice, Inbred Strains; D012903:Smell / Q000502:physiology