MAPT and Alzheimer disease: While it was previously hypothesized that tau fibrils were the leading cause of toxicity in tauopathy models, recent research has proposed that tau oligomers, an intermediate in the formation of tangles, are the actual cause of toxicity in these cases.[48] A study of a model of tauopathy with Drosophila melanogaster found neurodegeneration without the characteristic NFTs.[49] Thus, inhibiting the aggregation of tau is crucial for reducing toxicity and neurodegeneration in AD.