Early Alzheimer’s disease (AD) stages (that start even decades before clinical disease onset) are characterized by hippocampal dysfunction induced by amyloid-β oligomers (oAβ). Indeed, we have recently characterized hippocampal-dependent memory encoding and retrieval deficits and synaptic plasticity impairments in a non-transgenic mice model of early AD amyloidosis. Some protein changes underlying those deficits have been previously studied, but the spatial distribution within the hippocampus, and the possible sex dimorphism, has not been investigated before. Since each hippocampal part has clearly distinct functionality and connectivity, we postulated that some protein changes may be unique to each.Hippocampi from adult male and female mice intracerebroventricularly (icv.) injected with oAβ1‑42 or vehicle were studied by an innovative spatial proteomic analysis using matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry, that allows peptide detection with spatial resolution directly on hippocampal tissue sections, followed by protein identification by MS/MS. oAβ1‑42 induced hippocampal-dependent spatial memory and synaptic plasticity impairments were analyzed 1h post-injection as well.More than 200 peptides were detected by hippocampal spatial proteomics, and 34 were significantly up- or down-regulated by treatment or sex. A significant protein-protein interaction (PPI) was observed using STRING database, showing a relationship to long-term potentiation, the functional basis of memory.We show for the first time specific hippocampal changes in the proteome caused by early amyloidosis, giving new insight in valuable potential biomarkers for early diagnosis and therapeutic targets.Acknowledgements: PID2020-115823-GB100, MCIN and SBPLY/21/180501/000150/JCCM. AC held a Margarita Salas Postdoctoral Research Fellow funded by European Union NextGenerationEU/PRTR.