Fig. 1: Presynaptic t-LTD at P13–21 in the hippocampus switches to t-LTP at P35–42.
From: Astrocyte-mediated switch in spike timing-dependent plasticity during hippocampal development
a Left, scheme showing the general experimental set-up: R, recording electrode; S1 and S2, stimulating electrodes; right, pairing protocol utilized (Δt, time between the peak of the spike and EPSP onset). b A post-pre single-spike pairing protocol induces t-LTD at P13–21 (gray triangles, n = 7). This t-LTD is evident during the third week of development but it disappears during the fourth week (red squares, n = 6) and switches to t-LTP during the fifth week (black triangles, n = 13). The EPSP slopes monitored are shown. Traces show the EPSP before (1) and 30 min after (2) pairing. c Summary of the results. **p < 0.01, two-sided Student’s t test. d A post-pre protocol induces t-LTP at P35–42. The EPSP slopes monitored in paired (black triangles, n = 13) and unpaired pathways (white circles, n = 13) are shown. The traces show the EPSP before (1) and 30 min after (2) applying the induction protocol in the paired pathway, only the paired pathway showed t-LTP. e–h t-LTP induced by a post-pre protocol at P35–42 is expressed presynaptically. PPR decreases after t-LTP: sample traces at baseline and 30 min after induction of t-LTP, n = 13, **p < 0.01, two-sided Student’s t test. For detailed PPR values see Supplementary Data 1 e. The number of failures decreases after t-LTP induction f. Sample traces at baseline and 30 min after induction of t-LTP (n = 10, ***p < 0.001, two-sided Student’s t test). g Normalized plot of CV−2 versus mean EPSP slope yields data points mainly above the diagonal after induction of t-LTP (n = 13). h Miniature EPSP (mEPSPs) monitored during the baseline and after t-LTP induction in the presence of TTX (500 nm). Histograms and cumulative graphs show that after t-LTP induction, the frequency of mEPSPs increases, whereas the amplitude of mEPSP remains constant (n = 6). Scale bars: 1 mV, 1 s. *p < 0.05, two-sided Student’s t test. The error bars represent the S.E.M. Source data are provided as a Source Data file.
