This thesis reports on two applications of the STED (stimulated emission depletion) principle investigating alterations on the protein and lipid level. One hallmark of age-related neurodegenerative diseases is the abnormal post-translationally hyperphosphorylation of proteins. Here, the interplay of two main post-translational modifications of neurofilaments was investigated. The organization pattern of these modifications that were not resolvable by conventional light microscopy could finally be displayed with the about 10-times higher resolution of STED microscopy. Furthermore this...