The relationship between tetanus intensity and the magnitude of hippocampal long-term potentiation in vivo

► An intense tetanus causes a depression of hippocampal fEPSPs at low test intensities. ► An intense tetanus yields less LTP than a moderate tetanus at higher test intensities. ► Local changes at the stimulation site are likely to underlie these effects. ► In vivo, tetanus currents >500 μA should be avoided; 250-500 μA is probably optimal.