Synapse density measurements distant from plaques. (A) Synapse densities were quantified in floating sections stained with antibodies against DLG4 and synapsin. The regions analysed were cortical layers 2/3, hippocampal field CA1, stratum oriens (CA1 Or) and stratum radiatum (CA1 Rad) and the dentate gyrus molecular layer (DG LMol) in areas at least 50 µm distant from the closest fibrillar plaque. (B) DLG4 stained cortex of a wild-type mouse. Scale bar = 10 µm. (C) Automatically detected synaptic punctae in the square region highlighted in B. Scale bar = 5 µm. (D) DLG4 stained cortex of a Tg2576 mouse treated with control antibodies (IgG2a). Scale bar = 10 µm. (E) Automatically detected synaptic punctae in the square region highlighted in D. Scale bar = 5 µm. (F) Quantification of DLG4-positive punctae in the respective brain regions. (G) Quantification of synapsin-positive punctae in the respective brain regions. (H) Quantification of DLG4-positive punctae in the cortex and CA1 stratum radiatum of animals treated with control (IgG2a) antibodies, with conformation-unspecific (6G1) or oligomer-specific (A-887755) antibodies. Synapse densities were normalized to values in control animals treated with the same antibody. (F–H) n = 4 (wild-type) to 6 (Tg2576). (F) *P < 0.05; **P < 0.01 (t-test). (H) **P < 0.01, one-sample t-test.

Wt = wild-type; n.s. = not significant. PSD-95 is now known as DLG4.