Spontaneous and miniature excitatory synaptic transmission in CA1 neurons of 6-month-old adult APP/PS1 mice. Whole cell patch clamp recordings (voltage clamp) of synaptic currents from CA1 neurons in acute hippocampal slices. APP/PS1 mice specified by red symbols, WT littermate mice represented by black symbols. (A,B) spontaneous (s) and miniature (m) EPSCs in acute hippocampal slices from WT littermate and APP/PS1 mice, respectively. (C) APP/PS1 mice showed significantly higher mean sEPSC amplitudes (p = 0.008). Moreover, APP/PS1 mice showed significantly different cumulative sEPSC amplitude distribution (p < 0.0001). (D) CA1 neurons from APP/PS1 animals displayed comparable mean sEPSC frequencies as WT littermate animals (p = 0.11). However, APP/PS1 and WT mice expressed significantly different distribution of sEPSC inter-event intervals (IEIs; p = 0.005). (E) CA1 neurons from both WT littermate and APP/PS1 mice showed similar mean mEPSC amplitudes (p = 0.28), but significantly different cumulative mEPSC amplitude distributions (p < 0.0001). (F) CA1 neurons from APP/PS1 animals displayed similar mean mEPSC frequencies (p = 0.25) and mEPSC IEI distribution as WT littermates (p = 0.52). Digits in the bars show the number of recorded neurons per condition, at least from three different animals per group. Data shown as mean ± SEM. *: p < 0.05, statistical analyses were performed with two-tailed Student’s t-test (parametric data) and Mann–Whitney U-test (non-parametric data). Cumulative frequency distributions were analyzed with Kolmogorov–Smirnov test.