APOE and amyloidosis: In line with our ST findings, they highlight APOE- and amyloid-associated decreases in a number of PCs, a class of phospholipid linked to memory decline.70 Although a handful of PCs were highest in the E4 5XFAD brain, the majority of PCs were present in lower concentrations relative to the other groups, consistent with findings from the postmortem human brain.67 Regional segregation of lipid concentrations revealed that for most PCs, APOE-dependent changes in lipid concentrations were more striking in the isocortex, hippocampus, and fiber tracts relative to other brain regions.