Spatial learning and memory in aging C57BL/6 mice

We evaluated spatial behaviors as a function of age in C57BL/6 mice (4, 16, and 24 months). Simple exploration was measured in an open field, spatial memory was assessed with spontaneous alternation in a Y maze, and spatial learning and memory were measured using a 16 well hole-board with water rewards. The results indicate significant age-related decreases in exploration, significantly less alternation in the Y maze for the two older age groups, and significant age-related impairments in reference and working memory with the hole-board task. Deficits in the hole-board were not due to a lack of exploration, or time to complete the task. A factor analysis indicated that the behavioral measures factor differently with each other as a function of age, and a step-wise regression of the behavioral measures with age indicated that each task uniquely and independently revealed age-related impairments. In conclusion, the three tasks reported here can form a battery of tests to examine changes in spatially mediated behaviors and in the molecular/physiological mechanisms within the limbic system of the aging brain.