Marquez A, Guernsey LS, Frizzi KE, et al. - Researchers sought to evaluate how tau contributes to peripheral and central neurodegeneration using transgenic mice overexpressing human non-mutated tau (htau mice). At 3 and 6 months of age, indices of peripheral small and large fiber neuropathy and learning and memory performances have been evaluated. Peripheral neuropathy at 6 months of age is linked to overexpression of human tau. The research also offers evidence that, in memory deficits, non-mutated tau hyperphosphorylation plays a critical role. Furthermore, htau mice had decreased stromal corneal nerve length with preservation of sub-basal corneal nerves, consistent with a somatofugal degeneration. Prior to any cognitive deficits and peripheral neuropathy, corneal nerve degeneration took place. In patients with frontotemporal dementia (FTD), but not Alzheimer disease (AD), stromal corneal nerve loss was noted. In order to detect early neurodegeneration and distinguish FTD from AD, corneal confocal microscopy may be used.