Neurodegenerative diseases are among the most expensive, disruptive, and least well treated of human maladies, arguably because they are not well understood. Array tomography (AT) is a method for tissue imaging with resolution in all three dimensions sufficient to resolve individual synapses and provide quantitative characterization of multiple molecular constituents. AT imaging data enable description of neural networks in the context of the three-?dimensional tissue architecture. We beleve such data will enable researchers to begin to comprehend the proper function of neural circuits and, importantly, to begin to understand how it is that the various neurodegenerative processes present and progress. AT is, however, complex and expensive, and has been used in relatively few studies following the first publication in 2007 by Micheva and Smith. Aratome is currently providing AT services to the research community. The present application proposes proof-?of-?concept studies that a novel ligand development approach can be used to make ligands for AT that are superior to primary antibodies, in that 1) they can be bacterially expressed, which would make the reagents relatively inexpensive and of uniform quality; and 2) they are very small (45 amino acis) so that they will likely have greater access to target binding motifs, which is a major problem with the resin-?embedded tissue used for AT. Assuming we obtain proof-?of- concept under the present Phase 1 proposal, we would develop a catalog of reagents in Phase 2, which would be made generally available, and which would be integrated into a fully automated AT system, analogous to a NextGen Sequencer, that we are developing using separate funding.