NMDA receptor-independent LTP is not affected by apoE isoform. A) Long term potentiation induced by 2 trains of 200 Hz stimulation (arrow). Application of 100 μM APV for 5 minutes before and 20 minutes after 200 Hz stimulation. Expressed as slope of fEPSP, standardized to the first 20 minutes of recording. B) Average potentiation of last 20 minutes of recording. C57BL/6J = WT, green diamond, n = 5; apoE-deficient = E0, black circle n = 8; apoE2 TR = E2, blue square, n = 8; apoE3 TR = E3, purple inverted triangle, n = 7; apoE4 TR = E4, red triangle, n = 6. Data expressed as mean ± SEM.