Figure 1.

Immunohistochemical staining of the glutamatergic presynaptic bouton sites in human midfrontal gyrus tissue using antibodies directed against the glutamatergic presynaptic bouton site-specific marker vesicular glutamate transporter 1. A–D, Stainings are from subjects with no cognitive impairment (A), mild cognitive impairment (B), mild AD (C), or severe AD (D). Note the elevation in terminal number in B, taken from a subject with mild cognitive impairment, and the decreased presynaptic bouton-immunoreactivities in C and D, taken from subjects with mild and severe AD, respectively. E–G, The quantification protocol used to determine glutamatergic presynaptic bouton density in the midfrontal gyrus. Original digital images as shown in E were transformed into a file type that increases the computer's accuracy of detection (F). This transformed file format is then quantified by the computer using precise inclusion and exclusion criteria (as described in Materials and Methods) to accurately detect the elements of interest. G, The quantified image, in which dark blue coloration indicates those elements that were quantified, and light blue coloration indicates elements that failed to meet the required criteria and were hence omitted. Quantified data are then tallied and yielded in number format. Scale bars: D (for A–D), G (for E–G), 10 μm.