UNASSIGNED: In brains of @entity1 with @entity195 ( @entity195 ), Ab peptides accumulate in parenchyma and, almost invariably, also in the vascular walls. Although @entity1423 is, by definition, present in @entity195 , its impact is only incompletely understood. It occurs in a stereotypical spatiotemporal distribution within neuronal networks in the course of the disease. This suggests a role for synaptic connections in propagating Ab pathology, and possibly of axonal transport in an antero- or retrograde way-although, there is also evidence for passive, extracellular diffusion. Striking, in @entity195 , is the conjunction of tau and Ab pathology. Tau pathology in the cell body of neurons precedes Ab deposition in their synaptic endings in several circuits such as the entorhino-dentate, cortico-striatal or subiculo-mammillary connections. However, genetic evidence suggests that Ab accumulation is the first step in @entity195 pathogenesis. To model the complexity and consequences of @entity1423 in vivo, various transgenic (tg) rodents have been generated. In rodents tg for the @entity1 Ab precursor protein, focal injections of preformed Ab aggregates can induce Ab deposits in the vicinity of the injection site, and over time in more distant regions of the brain. This suggests that Ab shares with a-synuclein, tau and other proteins the property to misfold and aggregate homotypic molecules. We propose to group those proteins under the term "propagons". Propagons may lack the infectivity of prions. We review findings from neuropathological examinations of @entity1 brains in different stages of @entity195 and from studies in rodent models of @entity1423 and discuss putative mechanisms underlying the initiation and spread of Ab pathology.

Propagation of A   pathology: hypotheses, discoveries, and yet unresolved questions from experimental and XXXX brain studies.

@entity1 :: ('9606', 'Species') :: ['human', 'patients'] @entity1423 :: ('MESH:D001791', 'Disease') :: ['Ab aggregation'] @entity195 :: ('MESH:D000544', 'Disease') :: ['AD', "Alzheimer's disease"]
@entity1 :: (9606,Species) :: ['human']
