Taken together, these results show for the first time that the cleavage at the N-terminal tau with the release of diagnostic 20–22 kDa toxic neuropeptide (i.e.,NH2htau) is not only restricted to the retina and associated ocular structures of 6-month-old Tg2576 AD mice [12], but is also extended to their primary visual cortex (V1 area), in agreement with studies reporting that the accumulation of other pathogenic misfolded and/or hyperphosphorylated tau species is detectable along the entire visual system both in different preclinical AD animal models and AD subjects [7,79,80,81,82,83]. Here, MAPT is linked to Alzheimer disease.