Figure 5.

Action potentials are sufficient to rescue early-LTP from decay. (A) TBS (20–40 pulses in 100-Hz bursts) induces early-LTP, which decays to baseline levels by 3 h (n = 14). (B) Antidromic stimulation (3 × 2 theta-burst) rescues early-LTP from decay (n = 5). Induction was not significantly different between early-LTP and early-LTP rescues. (C) Example of rescue experiment. Traces (Inset) are the averages of 10 individual sweeps at the indicated times during the baseline period and at 7.5 h; scale bars represent 0.2 mV and 5 mS. (D) In two cases, 3 mM kynurenic acid was present during the stimulation to block activation of synapses from axon collaterals. One example experiment is shown. EPSP, excitatory postsynaptic potential