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. Author manuscript; available in PMC: 2008 Apr 30.
Published in final edited form as: Neurobiol Learn Mem. 2007 Feb 5;87(4):522–535. doi: 10.1016/j.nlm.2006.12.009

Figure 9.

Figure 9

Susceptibility to induction of LTD correlates with the behavioral measures of memory for the spatial version of the water escape task in aged animals. (A) The LFS induced changes in the slope of the synaptic response relative to the baseline (% of Baseline) was positively correlated with memory measured during the Day 2 probe trial (Discrimination index), such that aged animals exhibiting lower memory scores were associated with a reduction in the population EPSP slope following LFS. (B) Lower number of platform crossings was associated with a reduction in the EPSP slope following LFS in aged animals. The figure shows a scatter plot of the synaptic responses ranked according to the changes in the slope relative to the baseline (% of Baseline) following LFS, with the largest decrease in the synaptic response plotted at the bottom of the rankings. The platform crossings are ranked with more crossings on the right. A Spearman rank correlation indicated a relationship with p = 0.004. (C&D) The ranked scores for the Day 2 discrimination index and Day 2 platform crossings were averaged in order to identify the ten animals with the highest memory scores and ten animals with the lowest memory scores. The time courses of synaptic responses for pathways receiving LFS stimulation (filled symbols) and control pathways (open symbols) are plotted for the aged animals exhibiting the (C) lowest (n = 11 slices) and (D) highest memory scores (n = 13 slices). Each individual response was computed as a percent of the mean baseline response (dashed line) collected during the 10 min just prior to LFS stimulation (horizontal line). The SEMs are provided for every fifth sweep.