MAPT and Alzheimer disease: In order to study the possible relationship between the accumulation of hyperphosphorylated tau in neurons and the structural alterations of the AIS, we performed experiments with triple immunocytochemical staining of neocortical tissue from two sources: from autopsies of AD patients and from autopsy of individuals that were free of any known neurological or psychiatric illness, but with a high neurofibrillary tangles load (cases AB1 and AB6, see Table 1) that were considered controls.