PRNP and memory impairment: In spite of the large body of evidence that PrPC mediates the aberrant effects of Aβ oligomers, other studies have indicated that it is not a necessary component for the toxicity cascade induced by Aβ oligomers, as Aβ-induced LTP inhibition or memory impairment has also been reported to occur independently of the overexpression or ablation of PrPC in the transgenic mice [19,20,21].