The choice of the intervention we are going to apply is based on two `` proof of concept '' studies in humans ( Proc Natl Acad Sci USA @:@ -@ , @ ; Ann N Y Acad Sci @:@ -@ , @ ; Frontiers Syst Neurosci @:@ , @ ; PloS One @ ( @ ) : e@ , @ ) and on a recent animal study ( Front Syst Neurosci @:@ , @ ) .