Roles of tau and Aβ oligomers in AD. The tau-dependent pathway is associated to hyperphorylation and aggregation of tau-proteins inducing alterations of neuronal transportations and finally, neuronal death. The Aβ peptide-dependent pathway is associated to Aβ peptide production and toxic oligomer formation which alter synaptic functions. In a final step, Aβ peptide oligomers aggregate into amyloid plaques from oligomers which contribute to glial reaction and neuronal death.