Updated project metadata. We have used HiRIEF (High Resolution Isoelectric Focusing) LC-MS proteomics (Branca et al., 2014, PMID: 24240322) with isobaric tags (TMT10plex) to compare 32 post-mortem human brains in the prefrontal cortex (Brodmann areas 24 and 40) of prospectively followed patients with Alzheimer`s disease (AD), Parkinson`s disease with dementia (PDD), dementia with Lewy bodies (DLB) and older adults without dementia. LCMS raw files deposited here refer to samples from BA24 and BA40. For BA09 raw files, refer to the older dataset PXD006122. Proteomics database search files for all three Brodmann areas (BA09, BA24 and BA40) are posted here.