Thioflavin S staining was performed to determine the amyloid nature of the plaques and aggregates observed in the transgenic mouse brains. Thioflavin S (SIGMA, practical grade) was applied as a 1% wt./vol. solution in distilled water for 5 min at room temperature with no light. Slides were examined within 24 h post-staining, and photomicrographs were taken using an Olympus BX51 microscope and Microsuite FIVE software.