As shown in Figure 5C, IGFI (0.1mg/kg IV) persistently enhanced ex vivo Schaffer collateral LTP 24 hours postdosing as compared with vehicle 15 minutes after the first tetanus [F(1,12) = 17.8, P<.05], 15 minutes after the second tetanus [F(1,12) = 20.8, P<.05], as well as 40 minutes after the third tetanus [F(1,12) = 13.3, P<.05], indicating that IFGI persistently lowered the threshold for induction of LTP, and raised the ceiling magnitude of LTP, for up to 24 hours after administration. Here, IGF1 is linked to tetanus.