Spatial Memory Loss of Normal Aging: Animal Models and Neural Mechanisms

Normal aging is associated with mild, but significant changes in learning and memory. One brain structure that has been well-studied with regard to memory deficits that occur in advanced age is the hippocampus. The hippocampus plays an important role in memory in mammals, and is required in many species for accurate navigation and way-finding. Age-related hippocampal changes that may contribute to observed age-related spatial learning deficits are reviewed. Although cell numbers are well-preserved in the hippocampus during aging, there are specific changes that occur in connectivity and plasticity mechanisms in the hippocampus that have been correlated with spatial memory decline in rodents. These neural changes lead to alterations in hippocampal network dynamics that result in failures of information retrieval, and the behavioral appearance of older animals having a greater tendency to become lost. Understanding age-related changes in brain structure and function may ultimately lead to the development of methods that can attenuate memory loss and improve life quality of older individuals.