The degu (Octodon degus), a social diurnal caviomorph rodent endemic to Chile, spontaneously develops Alzheimer’s disease (AD)-like cognitive deficits, making it a natural model to study links between aging, sociability, and neurodegeneration. It shows 97.5% homology with human β-amyloid and a high misfolding rate (71.4%), suggesting its prion protein may also misfold in vivo. Ecological factors, such as habitat structure and group composition, are associated with brain anatomical variations and hemispheric asymmetry. To build a hippocampal histological atlas, eight adults (4 from El Salitre and 4 from Rinconada, Chile; balanced by sex) were perfused. Brains were stained with Hematoxylin and Erythrosin and examined by light microscopy. Structures and cellular components were delimited using stereotaxic atlases. Preliminary results show cytoplasmic vacuolization linked to neuronal nuclei in hippocampus, thalamus, hypothalamus, amygdala, and deep cortex, with area-dependent differences in number and distribution. In other wild species and humans, vacuolization associates with prion proteins and cognitive impairment, and to a lesser extent with AD pathology. These findings will be validated through immunohistochemistry and guide the search for homologous markers in Argentine caviomorphs such as the guinea pig (Cavia aperea).