Early and late LTP is enhanced in L-IFD mice. A, A single HFS train [arrow; five pulses (200 Hz, 100 ms) at a rate of 1/s] evoked LTP that lasts for up to 2 h in L-IFD mice (gray), but not in AL mice (black). B, Summary of the changes in fEPSP slope (mean ± SEM) at different times after a single HFS train. Representative fEPSP recordings, collected at the same time, from AL and L-IFD mice are also shown. C, Three HFS trains (arrows) induced indistinguishable LTP (lasting >2 h) in AL and L-IFD mice. D, Summary of changes in fEPSP slope (mean ± SEM) at different times after three HFS trains. Representative fEPSP recordings, collected at the same time, in AL and L-IFD mice are also shown (n = 6 for each group). +Statistical significance of AL and L-IFD mice in the same session; *statistical significance of the different session with respect to baseline recording in the same group. *p ≤ 0.05; **p ≤ 0.01; +++,***p ≤ 0.001.