Representation of the distribution of synapses according to their postsynaptic targets in the stratum pyramidale (str pyr) and radiatum (str rad) of CA1 in control and Alzheimer’s disease cases. (A, C, E and G) Percentages of axospinous (both on the head and the neck of dendritic spines) and axodendritic (both spiny and aspiny) asymmetric synapses (green) and symmetric synapses (red). The numbers of each synaptic type are shown in brackets. (B, D, F and H) Pie charts to illustrate the proportion of asymmetric and symmetric synapses according to their location as axospinous synapses (i.e. on the head or neck of the spine) or axodendritic synapses (i.e. spiny or aspiny shafts). Alzheimer = Alzheimer’s disease; Asym = asymmetric synapses; Sym = symmetric synapses.