Because AMD, glaucoma and Alzheimer's disease (AD) are chronic diseases that progress over decades, by the time they are diagnosed the underlying Aβ toxicity is already manifest. An important question is therefore if such ongoing toxicity can be reversed. We addressed this question by measuring long term potentiation (LTP) in hippocampal slices as an electrophysiological model of learning / memory in AD. GAL-101 was able to rapidly and completely restore LTP in hippocampal slices that had previously been impaired by Aβ.