(A) Representative image of a typical young WT cortico-hippocampal slice (350 µm) from co-culture (14 DIV) stained with DAPI (gray) to visualize nuclei (left). Dentate gyrus (DG), cornus ammonis 1 (CA1) and cortical (CTX) regions are indicated. An example of the co-culture dish is shown on the right. Co-culture includes 2 young WT (*, young co-culture) and 2 old APPPS1 (+, old co-culture) brain slices. 