This digital poster session explores how advanced neuroimaging can characterize the brain’s microenvironment and its relationship to cognition, aging, and neurological disease. Presentations span functional connectivity, diffusion microstructure, myelin and iron imaging, blood–brain barrier permeability, and emerging measures of glymphatic and perivascular transport. Studies include both human and animal models across conditions such as Alzheimer’s disease, multiple sclerosis, Parkinson’s disease, sleep disorders, vascular cognitive impairment, and systemic disease. Collectively, the session highlights how quantitative imaging biomarkers can reveal mechanisms of brain clearance, tissue integrity, and network disruption underlying cognitive dysfunction.