(B) Quantitative analysis of core-only plaques in old APPPS1 slices cultured alone (white bars) or in co-culture (gray bars) at 7 and 14 DIV reveals an increased number of core-only plaques upon co-culturing of old APPPS1 brain slices together with young WT slices. The values are expressed as percentages of core-only plaques from the total number of amyloid plaques. The values represent mean ± SEM from 3 independent experiments, each experiment including 3 independent slice culture dishes (***P < 0.001). 