There is no clear connection between the in-vivo and in-vitro experiments. You did the culture experiment to understand the molecular basis of the EE effect, and you exposed the culture to high Mg, which is likely to suppress network activity, but to allow better effect of chemical LTP. You did not use wt to examine the effect of cLTP, and in fact, the wt cells were not affected by high Mg, unlike previous citations. Also, in the in-vivo experiments, spine length goes down in both wt and KO cells. The difference is that the spine density is already higher in the KO cells, why is this considered 'abnormal', perhaps this is a rebound to an effect of the KO produced elsewhere in the brain? Also, there are images of PSD95 in the wt, but no quantification, and no quantification of vGlut.