Studies were done in 7-8 month old mice where there is an enormous Ab burden ...not a surprise that there is a deficit in LTP. Must do studies at 7-8 weeks at the time when deposition is first observed in this model. . The most important control is that the PS1L166P mouse (or APPswe mouse) was not analyzed. Malinow and colleagues and others have reported that mice expressing mutant PS1, alone, show decreased LTP. in Shaeffer collaterals. So, are the LTP phenotypes due to huge amyloid burden, expression of mutant PS1 or mutant APP?