Form follows function: morphology as a map of mechanisms in neurodegenerative disease pathology

Across neurodegenerative diseases, the shape and spatial organization of pathology carry rich mechanistic information. Vacuoles, spongiosis, oligodendroglial coiled bodies, dendritic dystrophic neurites, amyloid plaque compactness, and phase-separated droplets each reflect distinct cellular identities, subcellular compartments, trafficking pathways, and biophysical material states. Here, I synthesize morphological signatures across neurodegenerative diseases to propose a framework that links morphology to mechanism. Morphology is neither incidental nor merely descriptive. Rather, it is a readout of the basic mechanisms that govern self-assembly of proteins into aggregates, the cell's attempts at proteostasis (clearance, sequestration, and transport), and the failure that ensues.