Amyloid fibril protein aggregates are the hallmark of many neurodegenerative diseases like Alzheimer's, but the relationship between their molecular structures and resulting cytotoxicity is still unclear.  We are developing Raman Chemical Imaging techniques to assess how the structure of different fibril polymorphs influences their ability to grow and spread from one region of the brain to another. The ultimate goal of this is to establish structure-toxicity relationships of pathophysiologically relevant fibril polymorphs and gain molecular insights into the variation of clinical phenotypes observed in Alzheimer's Disease.