animals. In addition, intracerebral injections of anti-Aβ antibodies into the hippocampus of 3xTg-AD mice not only reduced Aβ accumulation but also resulted in clearance of early-stage tau pathology, although later-stage lesions were resistant.65 These studies thus show that modulating Aβ affects tau pathology and suggest that tau pathology may be downstream of Aβ generation; this notion has also been supported by recent studies showing that behavioral deficits in APP FAD mutant mice are reduced when endogenous tau is removed by breeding the APP transgene onto a tau-null background.66
