ABSTRACT
Aging-related cognitive decline has enormous, tangible costs to national and family health care. This chapter provides the behavioral evidence characterizing the aging-related decline in performance on hippocampus-dependent tasks in rodent models. It considers the aging-related anatomical, physiological, and biochemical changes that occur in the whole hippocampus, as well as in hippocampal subregions. One possible anatomical substrate for aging-related learning and memory impairment is a compromise in the synaptic connections within the hippocampus. Aging-related spatial learning impairments occur in the absence of marked, widely distributed changes in hippocampal presynaptic markers, although limited changes do occur in specific layers of hippocampal subregions. Microenvironmental changes in the aging brain may be key elements in the functional decline that occurs across the lifespan. Aging-related cognitive impairment is reflected in performance deficits on hippocampal-dependent tasks such as the Morris water maze test of spatial learning and memory.
