Brains from young (5 wph) and old (39 wph) were homogenized and clarified lysates separated by size-exclusion chromatography (SEC). For each age group, two pools of brains were processed separately. For each experiment (4 in total), 39 fractions were collected along the chromatogram, digested into peptides and analysed by Data Independent Acquisition (DIA) quantitative mass spectrometry. 