Fig. 13

A cross-sectioned 90 µm thick brain slice is collected on a 400-mesh hexagonal grid (a), and the two cut edges of the slice are enlarged in (b). Perfusion-fixed brain slices labeled with shank 3 (c), homer 1/2/3 (d), and homer 1 (e), three different antibodies against these PSD scaffold proteins [21, 30]. Labeling density decreases from the cut edges of the slices on left toward the deeper tissue of the slices on right (c–e). The penetration gradient is similar between c and d where two antibodies were used on slices from two different mice. However, depth of penetration for the third antibody (e) appeared to be shallower, even though the slice was from the same animal as in (d). Many PSDs were unlabeled (open arrows in e) beyond 2 µm deep from the cut edge. The two bars on bottom of d were each 1 µm long and marked the depth from the cut edge of the slice