Fig. 1

Tg2576 MCs exhibit increased excitatory and decreased inhibitory synaptic activity. (A) 1. An illustration of the location of the hippocampus (left) and a cross-section through the hippocampus showing the DG (center). On the right is a micrograph of the DG illustrating a MC that was recorded with a biocytin-filled electrode (blue). 2, 3. The timeline of the slice preparation and recordings of spontaneous synaptic activity and intrinsic properties from MCs (2, current cl 3, voltage clamp). (B) (1) Representative traces of sEPSPs from WT (black) and Tg2576 mice (red). (2) Quantification of sEPSP frequency showed that mean sEPSP frequency was significantly greater in Tg2576 mice but not mean amplitude. (3) Frequency distributions of sEPSP amplitudes were different in the genotypes. Red and black arrows point to the maximums. (4) The cumulative distributions revealed significant differences between WT and Tg2576 MCs. C. (1) Representative traces of AMPA-sEPSCs. (2) There were no significant differences in mean frequency or amplitude. (3) Frequency distributions showed genotype differences with more small events in Tg2576 mice, and more large events in WT mice (compare arrows pointing to the maximums). (4) The cumulative distributions were significantly different in WT and Tg2576 mice, consistent with the frequency distributions. D. (1) Representative traces of sIPSCs. (2) There was a significant reduction in mean sIPSC frequency and amplitude in Tg2576 mice. (3) Frequency distributions of events show significant differences. (4) The cumulative distributions revealed significant differences between WT and Tg2576 MCs. For this and all other figures, data are represented as mean ± SEM. *p < 0.05. Details of statistical comparisons are in the text and supplemental tables.