Involvement of hippocampal synaptic plasticity in age-related memory decline

This article examines the functional significance of Ca2+-dependent synapti c plasticity in relation to compromised memory function during aging, Resea rch characterizing an age-related decline in memory for tasks that require proper hippocampal function is summarized, It is concluded that aged animal s possess the mechanisms necessary for memory formation, and memory deficit s, including rapid forgetting, result from more subtle changes in memory pr ocesses for memory storage or maintenance. A review of experimental studies concerning changes in hippocampal neural plasticity over the course of agi ng indicates that, during aging, there is a shift in mechanisms that regula te the thresholds for synaptic modification, including Ca2+ channel functio n and subsequent Ca2+-dependent processes. The results, combined with theor etical considerations concerning synaptic modification thresholds, provide the basis for a model of age-related changes in hippocampal synaptic functi on. The model is employed as a foundation for interpretation of studies exa mining therapeutic intervention in age-related memory decline. The possible role of altered synaptic plasticity thresholds in learning and memory defi cits suggests that treatments that modify synaptic plasticity may prove fru itful for the development of early therapeutic interventions in age-related neurodegenerative diseases. (C) 1999 Elsevier Science B.V, All rights rese rved.