Hyperphosphorylated tau in Alzheimer's disease disseminates along pathways predicted by the Structural Model for Cortico-cortical Connections.

In Alzheimer´s disease (AD), hyperphosphorylated tau spreads along the cerebral cortex in a stereotypical pattern that parallels cognitive deterioration. Tau seems to spread transsynaptically along cortico-cotical pathways that, according to synaptic tract-tracing studies in nonhuman primates, have specific laminar patterns related to the cortical type of the connected areas. This relation is described in the Structural Model.

Comparison of the predictive power of two models of cortico-cortical connections in primates: the distance rule model and the structural model.

Synaptic tract-tracing studies in macaques have provided a wealth of data about cortico-cortical connections that have been used to identify regularities and propose models and theories to explain cortical connectivity. The two most relevant of these models are the distance rule model (DRM) and the structural model (SM). They relate the strength and laminar pattern of cortico-cortical connections to two different factors: Euclidean distance (according to the DRM) and cortical type distance (according to the SM).