Based on the reconstruction of almost 20 000 dendritic spines in fixed hippocampal tissue from AD patients by intracellular injections of Lucifer yellow and staining with specific anti‐tau phosphorylated antibodies, it was revealed that the diffuse accumulation of phosphorylated tau in a putative pre‐NFT state did not induce changes in the dendrites of pyramidal neurons, whereas the presence of tau aggregates forming intraneuronal NFTs was associated with progressive loss of dendritic spines and changes in their morphology (Merino‐Serrais et al. The gene discussed is MAPT; the disease is Alzheimer disease.