Another set of experiments in transgenic animal models of neurodegenerative diseases also identified the “spread” of gene expression properties in neighboring neurons [7]: in these models, the accumulation of Tau in neurons expressing a transgene resulted in tau aggregates developing in adjacent neurons lacking the transgene but receiving projections from transgene-expressing neurons, possibly through a trans-synaptic prion-like mechanism [7]. This evidence concerns the gene MAPT and neurodegenerative disease.