Figure 5. Synaptic states are discriminated by RSE.

A–B, representative RSE after depotentiation (A) and dedepression (B). A, depotentiation was induced by LFS (900 pulses at 1 Hz) applied 5 min after tetanus (100 pulses at 100 Hz). Only fEPSP₁ was returned to the baseline level, but later fEPSPs were kept augmented after depotentiation. The right panels merged raw traces with pseudocolour images of STP ratios (for details, see Fig. 3 legend). B, weak tetanus (50 pulses at 100 Hz) 5 min after low-frequency stimulation was given to induce dedepression. Again, only fEPSP₁ was returned to baseline. C, artificially normalized LTP preserves the level of RSE. Potentiated synaptic responses (grey) were adjusted to pretetanus baseline by reducing the intensity of test stimulation. Even though fEPSP₁ returned to the pretetanus level, synapses preserve the level of RSE. n = 8 slices. D, summary of RSE induced by various types of long-term plasticity.