Figure 6

Synapse densities in wild type, APP23 and APP48 mice. a: Loss of asymmetric synapses in the frontocentral cortex of 3- and 15-month-old APP23 mice in comparison to wild type mice. 18-month-old APP48 and wild type mice did not differ significantly in the density of asymmetric synapses. At 3 months of age APP48 mice had even more asymmetric synapses than wild type animals. In CA1 there were also slightly less asymmetric synapses in APP23 mice than in wild type controls and APP48 mice. However, these differences were not significant. b: There were no significant differences in the number of symmetric synapses in the frontocentral cortex and in CA1 in 3- and 15-18-month-old animals. c: APP23 and APP48 mice of both age groups exhibited reduced numbers of CA1 neurons compared to wild type mice whereby CA1 neuron loss was most pronounced in APP23 mice. d: The number of neurons in the frontocentral cortex did not vary significantly among 15-18-month-old wild type, APP23, and APP48 mice. Therefore, younger animals were not studied for the number of neurons in the frontocentral cortex. *p < 0.05, **p < 0.01, ***p < 0.001 (Further statistical analysis: Additional file 2). Means and standard errors are depicted. (Some data were previously published in a different context [16, 19]).