The major long-term goal of our research is to develop in rats a behavioral model for the effects of glucose and fructose on memory storage, reconsolidation, and retrieval. Previously we have shown that the dose-response curves for glucose and fructose on initial memory storage and subsequent reconsolidation follow similar cubic trends. The overall aim of the proposed research is to specify the age-dependent characteristics for this behavioral model. In the proposed experiments we use Fisher-344 rats (3-, 12-, and 24-months old) and we focus on understanding the effects of glucose and fructose on the modulation of recently reactivated or retrieved memories. The general behavioral paradigm we employ is a passive-to-active avoidance negative transfer (discrimination reversal) paradigm and an interpolated reactivation or reminder treatment (re-exposure to the experimental room and footshock). In Experiment 1 we characterize the dose-response function for the effects of fructose on memory in rats across the life span and in Experiment 2 we determine the optimal dose of fructose needed for modulating a recently reactivated memory in these same rat age groups. The purpose of Experiment 3 is to extend the results to rats of various ages in our investigation of the effects of repeated reactivation treatments on memory. In Experiment 4 we investigate the effects of glucose administration on passive avoidance memories of various ages (1 to 21 days) and in Experiment 5 on reactivated memories of various ages (1 to 21 days). The results from our experiments will provide the experimental basis for the behavioral model for the effective use of the important memory modulator glucose, or for any similar modulatory agent on reactivated memories. What is more, the results of our experiments are important because glucose can attenuate impairments in memory in human clinical populations.
