Age-dependent disruption in hippocampal theta oscillation in amyloid- overproducing transgenic mice

Transgenic mice are used to model increased brain amyloid(A ) and amyloid plaque formation reflecting Alzheimer’s disease athology. In our study hippocampal network oscillations, population spikes, and long-term potentiation (LTP) were recorded in APPswe/ S1dE9 (APP/PS1) and presenilin1 (PS1) transgenic and wild type mice at 2, 4, and 8 months of age under urethane anesthesia. ippocampal theta oscillations elicited by brainstem stimulation were similar in wild type and PS1 mice at all age groups. In contrast, PP/PS1 mice showed an age-dependent decrease in hippocampal activity, characterized by a significant decline in elicited theta power and requency at 4 and 8 months. Magnitudes of population spikes and long-term potentiation in the dentate gyrus were similar across groups t both 4 and 8 months. In APP/PS1 mice, soluble and insoluble A , and hippocampal and cortical plaque load increased with age, and the isruption in hippocampal theta oscillation showed a significant correlation with plaque load. Our study shows that, using in vivo lectrophysiological methods, early A -related functional deficits can be robustly detected in the brainstem-hippocampus multisynaptic etwork. 2012 Elsevier Inc. All rights reserved.