Quantification of presynaptic cytomatrix protein levels by immunocytochemical staining of control (C) and silenced (S) cultures. A, B, Example of whole-cell staining for Bassoon (left image and green in the overlay image in the middle), and synaptophysin (right image and magenta in the overlay in the middle). The white rectangle delineates the region shown in higher magnification in C. C–G, The images show overlays of staining of the protein of interest (in the middle and green in overlay images) with MAP2 (left, in magenta) and with synaptophysin (magenta in the right overlay). Scale bars: B, 20 μm; and C, 5 μm. H, I, Quantification of the number of puncta along a 20 μm segment of dendrite (H) and the intensity of staining (I). Values are averages from two independent experiments and are normalized to control. Bars represent mean values; whiskers, SEM. The statistical significance was assessed using a t test; *p < 0.05, ^#p < 0.0001. J, K, Distribution of immunofluorescence intensities in individual synapses is shown for Bassoon (J) and RIM (K).